Variety Of Atmospheric Conditions Research Articles

A novel global MPPT technique to enhance maximum power from PV systems under variable atmospheric conditions

A novel global MPPT technique to enhance maximum power from PV systems under variable atmospheric conditions

Dynamics of Separation of Unmanned Aerial Vehicles from the Magnetic Launcher Cart during Takeoff

Most aircraft launchers exhibit a rapid acceleration of the launching aircraft, often exceeding ten times the acceleration due to gravity. However, only magnetic launchers offer flexible control over the propulsion force of the launcher cart, enabling precise control over the aircraft’s acceleration and speed during its movement on the launcher. Consequently, extensive research is being conducted on magnetic launchers to ensure the repeatability of launch parameters, protect against aircraft overloads, and ensure operator safety. This article describes the process of modeling and analyzing the dynamical properties of a launch cart of an innovative prototype launcher, which employs a passive magnetic suspension with high-temperature superconductors, developed under the GABRIEL project. The developed mathematical model of the magnetic catapult cart was employed to conduct numerical studies of the longitudinal and lateral movement of the cart, as well as the configuration of the UAV–cart system during UAV takeoff under variable atmospheric conditions. An essential aspect of the research involved experimentally determining the magnetic levitation force generated by the superconductors as a function of the gap. The results obtained demonstrate that the analyzed catapult design enables safe UAV takeoff. External factors and potential vibrations resulting from uneven mass distribution in the UAV–cart system are effectively balanced by the magnetic forces arising from the Meissner effect and the flux pinning phenomenon. The primary advantage of the magnetic levitation catapult, in comparison to commercial catapults, lies in its ability to provide a reduced and consistent acceleration throughout the entire takeoff process.

Degradation phenomena of Templo Pintado painted plasters

Weathering processes of Templo Pintado (Painted Temple) caused by environmental and climatic agents have been investigated in this work. The temple is part of the archaeological complex of Pachacamac, situated in a desert area of Western Peru characterized by high relative humidity, temperature, relevant winds, and remarkable solar radiation. These atmospheric conditions result in wet-dry cycles and wind erosion, eventually inducing pulverization, exfoliation, and detachment in plaster and painted surfaces. The seasonal variation of atmospheric conditions was monitored on a daily basis for five years, revealing that the seasonal cycles exhibit great similarity. Experimental results show a linear correlation between loss of material and environmental temperature. In particular, degradation increases with temperature rises. Moreover, high temperatures are combined with stronger winds and drying of materials (wet-dry cycles), which contribute to accelerating degradation kinetics.

On the correlation between thermal imagery and fugitive CH4 emissions from MSW landfills

Landfill gas (LFG) is related to the biochemical processes generating heat and releasing CH4, CO2, and other gases in lower concentrations, which result in environmental impacts and risk of local explosion. Thermal infrared imagery (TIR) is employed to detect CH4 leakage as a risk control approach. However, the challenge for LFG leakage detection using TIR is establishing a relation between the gas flux and the ground temperature. This study evaluates the problem of a heated gas flowing through a porous medium column where the upward surface exchanges heat by radiation and convection to the environment. A heat transfer model that considers the upward LFG flow is proposed, and a sensibility analysis is developed to relate the flux to the ground temperature level in the condition of non-income solar radiation. An explicit equation to predict CH4 fugitive flow as a function of temperature anomalies of the ground was presented for the first time. The results show that the predicted ground surface temperatures are consistent with the literature’s experimental observations. Moreover, the model was complementarily applied to a Brazilian landfill, with in situ TIR measurements in an area with a slightly fractured cover. In this field observation, the predicted CH4 flux was around 9025 g m−2 d−1. Model limitations concerning the soil homogeneity, the transient variation of atmospheric conditions or local pressure, and soil temperature difference in low-flux conditions (related to TIR-cameras accuracy) require further validation. Results could help landfill monitoring in conditions of a high-temperature ground anomaly in dry seasons.

A global MPPT technique for PV systems under partial shading conditions

ABSTRACT Maximum Power Point Tracking (MPPT) algorithms are used to obtain maximum power from PV (Photovoltaic) systems in variable atmospheric conditions. Partial shading conditions (PSCs) have an important effect causing the maximum power points of PV systems to change. In this study, a new hybrid MPPT algorithm was proposed by combining Voltage Scanning (VSC) and Cuckoo Search Algorithm (CSA) methods to obtain maximum power from a PV system running under PSC. To test the proposed method, a 252.6 kW grid-connected PV system with 609 panels, including 7 serial panels and 87 parallel strings, was created in the MATLAB/Simulink environment. This system was tested under 10 different PSCs by using VSC, Particle Swarm Optimization (PSO), CSA, and the proposed MPPT methods. The average tracking efficiency and speed of the proposed method under these conditions were obtained as 99.74% and 0.3s, respectively. Under PSCs, the proposed method achieved the highest tracking efficiency of 99.92%, while the highest tracking speed that it achieved was 0.22s. On the other hand, the superiority of the proposed hybrid MPPT algorithm was clearly demonstrated by comparing it to the VSC, PSO, and CSA methods.

Physical and morphological properties of first-year Antarctic sea ice in the spring marginal ice zone of the Atlantic-Indian sector

AbstractThis study presents the first dataset of physical and textural properties of sea ice collected in the South Atlantic and Indian Ocean sector of the Antarctic marginal ice zone (MIZ). Observations of sea ice from this region in the austral spring 2019, including sea-ice core temperature, salinity, crystal size, texture, oxygen isotopes and stratigraphy, were used in conjunction with a Lagrangian back-tracking algorithm and atmospheric reanalyses. This method relates the reconstructed synoptic conditions to sea-ice growth along the transect. A significant difference was found between the stratigraphy of consolidated pack ice samples collected at the same latitude and spanning over 550 km eastwards. The eastward group was found to have more disturbances in their stratigraphy which is attributed to the highly variable atmospheric and sea-ice conditions together with varying wave penetration through the sea-ice pack, notably during the passage of an intense polar cyclone, while the westward group showed no signs of disturbance or deformation. These results indicate that consolidated Antarctic sea-ice floes of similar thickness and from the same latitude in the MIZ have distinct stratigraphic properties, which will influence their physical and biogeochemical features.

The general formulation of the energy equation and the impact of enthalpy diffusion on multi-component droplet heat and mass transfer

A key aspect of modeling the heat and mass transport of droplets is the description of diffusion transport, and multiple approaches exist to address it. While many contributions focus on the description of the mass transfer, details about the energy formulation to describe the droplet’s heat transfer are seldom developed in the literature. This work demonstrates that a general gas-phase energy formulation can be obtained independently from the species diffusion transport modeling while incorporating multi-species enthalpy diffusion terms with a simple expression. Considering the ideal gas simplification, it is shown that a simple choice of specific heats is sufficient to characterize the inclusion or not of multi-species enthalpy diffusion effects. Furthermore, it is also demonstrated that the final energy expression degenerates in the single-component limit to the same energy formulation as in the model of (Abramzon and Sirignano, Int. J. Heat and Mass Trans, Vol.32(9), pp.1605–1618, 1989), considered as a reference in the literature. Simulations are conducted for droplets of multiple fuel compositions in varied atmospheric conditions to represent spray combustion scenarios and evaluate the impact of incorporating or not the enthalpy diffusion term, and conclude on the need and ease of use of the proposed energy formulation.

Evaluating Spatiotemporal Trends in Infrasound Propagation Using Seismoacoustic Arrivals from Repeating Explosions

ABSTRACT Recent studies have demonstrated the utility of seismic stations for recording acoustic signals from events of interest. Here, we present an analysis of seismoacoustic arrivals originating from weekly controlled munition disposals at the McAlester Army Ammunition Plant (McAAP) in Oklahoma over a period of nine months during 2019. These arrivals were recorded on 121 temporary and permanent seismic stations across Oklahoma and surrounding states. Arrivals were identified by a human analyst team. Because of its consistency and duration, the McAAP dataset provides an opportunity to study the spatial and temporal variability of infrasound propagation because it relates to seasonally variable atmospheric conditions. Recorded arrivals identify an acoustic shadow zone ranging in distance from 50 to 200 km of the source, along with seasonal directional shifts in the stratospheric duct. Acoustic raytracing is used to produce comparisons of predicted and observed arrival dynamics, concluding that current atmospheric specifications do not capture the full complexity of the atmosphere.

A new technique for monitoring plant transpiration under field conditions using leaf optical dendrometry

Monitoring plant transpiration (Ec) is important for quantifying irrigation amounts and maintaining optimum soil moisture conditions for maximum growth potential. However, real-time quantification of Ec dynamics under field conditions is still challenging due to technical limitations. Here, we present a new approach for monitoring plant water use using continuous measurement of stem water potential dynamics (Ψstem) under non-limiting water conditions. According to Darcy's law, if daytime root to stem hydraulic conductance (Kr-s) remains constant and the contribution of plant capacitance to Ec is minimal or accounted for, then daytime Ec could potentially be continuously inferred from Ψstem dynamics. We investigated the viability of this approach by first quantifying the dynamics of daytime Kr-s and the transient buffering effects of plant capacitance in irrigated plants of two crop species with contrasting physiology and life history: the perennial herbaceous Tanacetum cinerariifolium and the annual monocot Triticum aestivum. Daytime Kr-s dynamics and the effects of plant capacitance were determined by continuously and simultaneously measuring Ψstem with optical dendrometers and Ec with gravimetric method under naturally variable conditions of light, temperature and humidity. Kr-s remained relatively stable throughout the day and the effects of plant capacitance were negligible in both species under field conditions implying that the dynamics of Ec can be inferred from Ψstem. This was clearly supported by the close agreement between measured Ec and that predicted from the optically derived Ψstem. We conclude that optical dendrometry has the potential to continuously monitor both Ec and plant hydration status at high accuracy and temporal resolution under naturally variable atmospheric conditions and optimum water supply. Combining these two aspects of the optically derived Ψstem should create new opportunities to monitor crop water use and maintain plant hydration at optimum levels for maximum productivity in various crops under field conditions.

Maximum power point estimation of MSX-60 poly-crystalline standalone solar PV system

In the recent decades, solar photovoltaic (PV) systems are one of the attractive renewable energy sources among the researchers. The maximum power generated by PV arrays varies with the variation in climatic conditions and exhibits non-linear P–V & I–V characteristics. Solar PV systems require external control to extract maximum power as their conversion efficiency is generally very low. The Maximum Power Point Techniques (MPPT) plays an important role to extract maximum power at every instant of time through an algorithm based automatic control. It automatically adjusts the power interface and extracts maximum possible power from PV array under variable irradiance, shading, and under variable temperature. The evaluation of performance of solar PV systems and MPPT techniques is become essential now days to enhance their performance under real–life variable atmospheric conditions. In additions to this, the performance of Perturb & Observe (P&O), one of the mostly used and robust MPPT techniques is analyzed in this work under continuously variable solar irradiance and temperature. Different patterns of variable solar irradiance are considered along with the real–life variable temperature throughout the day. The simulation has been carried out in MATLAB/Simulink 2020a to analyze the performance of P&O MPPT technique. Various performance parameters viz. Pout_max, Pout_avg, Ppv_max, Ppv_avg, Vout_max, Vout_avg, Vpv_max, Vpv_avg and conversion efficiency η are considered to analyze the performance of MPPT technique.

Performance comparison between proportional–integral and backstepping control of maximum power in photovoltaic system

The major problem with photovoltaic systems is to extract the maximum power with better performance and good efficiency as long as there are large variations in atmospheric conditions. To do this, we made a comparative analysis between two controllers, Proportional-Integrator (PI) and backstepping based on a photovoltaic system made up of two parts, the first is the Photovoltaic (PV) panels which are used to convert solar irradiation to an electric current, the second is a boost converter which is used to provide the maximum power. The Perturb and Observe algorithm is used to generate the reference voltage in order to follow it by the two controllers (PI and backstepping) and therefore generate the maximum power. We are considered some parameters for this comparison such asthe efficiency of the controllersto follow the reference power despite the rapid change in atmospheric conditions as well as the response time of the system and the ripples in the transient phase.

Computational modeling of a PV-PCM passive cooling system during a day–night cycle at arid and semi-arid climate zones

This work investigates the use of phase change materials (PCMs) as a passive cooling system to increase the electric power generation of photovoltaic panels (PV) by a reduction of the temperature of the panels. This study aims to evaluate different configurations of PV-PCM cooling systems, by changing the phase change material, to achieve a high efficiency in a silicon PV. Each configuration is studied for three day–night cycles under seasonal variable atmospheric conditions. Two Chilean cities with a semi-arid climate and arid climate – Vicuña and Calama, respectively – were selected as the study locations. The development of the PV-PCM improved system is carried out by solving the unsteady thermal energy equation with computational simulations using the finite volume method (FVM). An Enhanced Conduction Model (ECM) was used to include the convective heat transfer in the melted PCM. The ECM was validated against numerical values of a PV-PCM system finding a maximum deviation for the PV frontal temperature of 1.23 °C. The numerical model was validated with experimental and numerical results of a PV-PCM system during a 24-hour cycle with time-varying atmospheric conditions. The results obtained indicate that the use of phase change materials as a cooling system decreases up to 17.5 °C the temperature at the PV, diminishing the losses of efficiency and increasing the generation of electricity. The electrical production in one year increases by 5.8% for Vicuña and 4.5% for Calama when a layer of CaCl2–6H2O with a thickness of 40 mm is used.

Glass-ceramic route to NASICON-type Na Ti2(PO4)3 electrodes for Na-ion batteries

Glass-ceramic processes to prepare NASICON-type Na x Ti 2 (PO 4 ) 3 , which is an anode candidate for sodium-ion batteries, from 30Na 2 O–40TiO 2 –30P 2 O 5 glass have been investigated with varied atmospheric conditions. By annealing in the inert (N 2 ) atmosphere, the glass started crystalizing into NASICON-type NaTi 2 (PO 4 ) 3 with rhombohedral symmetry at ∼600 °C followed by crystallization of other phases to be multiphase mixtures at higher temperatures. In contrast, in the reducing (5% H 2 /Ar) atmosphere, NASICON-type Na 3 Ti 2 (PO 4 ) 3 with triclinic symmetry is crystallized at >∼800 °C. The formation of Na 3 Ti 2 (PO 4 ) 3 is associated with a loss of excess oxygens in the initial glass composition and a reduction of Ti from Ti 4+ to Ti 3+ . The reduction process upon the glass-to-ceramic conversion was traced by in-situ observation during the thermogravimetric analysis. It is also revealed that the electrochemical Na + -storage capabilities of the glass-ceramic electrodes are correlated with the Na-ion occupancy between these two phases, and their phase fractions affect the charge-discharge properties of Na-ion cells. Finer glass-ceramic powders could improve the electrochemical properties and achieve almost 80% of its theoretical capacity.

Determinants of Spatial Variability of Ice Thickness in Lakes in High Mountains of the Temperate Zone—The Case of the Tatra Mountains

Vertical and horizontal variation in the ice cover of mountain lakes in the temperate climate zone has not been thoroughly studied. The study concerned ice phenomena in four lakes located in the Tatra National Park in the Tatra Mountains (the Czarny Staw Gąsienicowy, Czarny Staw pod Rysami, Morskie Oko, and Smreczyński Staw). The research, which was conducted in the 2018/2019 winter season, included an analysis of variability in atmospheric conditions, an analysis of presence of ice phenomena on satellite images, field work (measurements of ice layer and of snow and slush layer thickness were conducted at a total of 151 sites), and statistical analyses. It was determined that negative air temperature was just one factor among those that determined the maximum thickness of the ice forming on lakes in high mountains. It was found that in addition to ambient thermal conditions, a major factor affecting the magnitude of variation in lake ice thickness was the thickness of the snow overlying the ice and its spatial variability. Thicker ice cover tended to form in areas where a thick layer of snow was deposited. The decisive factor that contributed to a significant variation in ice thickness between lakes was the uneven accretion of snow ice from above. The maximum ice thickness values modeled using Stefan’s formula were significantly underestimated (accounting for 38–61% of the ice thickness measured) relative to the highest ice thickness values found empirically at the end of the winter season. Study results fill a gap in our knowledge and methodology related to vertical and horizontal variation in the ice cover of mountain lakes; they also have significant applications, indicating the risk of winter use of water bodies with different ice cover structure, thickness, and extent.

Comparative study on the thermal performance and economic efficiency of vertical and horizontal ground heat exchangers

The ground-coupled heat pump is a shallow geothermal exploitation method taking soil as the thermal energy source. The ground heat exchanger is an important component of this system, which includes vertical or horizontal configurations. However, to the best of our knowledge, few studies exist involving the comparison of thermal performances and installation costs of two heat exchanger types considering the influence of ground climate, which makes the selection of heat exchanger configuration challenging for a specific field application. Hence, a 3-dimensional numerical model considering the variations of atmospheric conditions and soil water content is constructed in this paper. Based on this model, the thermal performances and economical efficiencies of vertical and horizontal ground heat exchangers are compared. The results indicate that the thermal performance difference between the two heat exchangers is greater in winter than in summer. The thermal performance is hardly influenced by the injection mass flow rate, while it is considerably affected by the length of heat exchanger. The thermal power rises linearly with the increase in heat exchanger length, and the increment of the vertical ground heat exchanger is higher. In addition, when the heat exchanger length is shorter than 40 m, the installation cost and thereby the total cost of the horizontal ground heat exchanger is considerably higher. With regard to both the thermal performance and economic efficiency, a vertical ground heat exchanger is only recommended when installing a single shallow ground heat exchanger. Cited as: Cui, Q., Shi, Y., Zhang, Y., Wu, R., Jiao, Y. Comparative study on the thermal performance and economic efficiency of vertical and horizontal ground heat exchangers. Advances in Geo-Energy Research, 2023, 7(1): 7-19. https://doi.org/10.46690/ager.2023.01.02

Similarity Measure of Images using SIFT and ORB Feature Matching

Abstract: In this study, similarities between images are identified and examined. A collection of images made from an image of the same scene or item taken under varied atmospheric conditions, such as different perspectives or lighting settings, and then altered in myriad ways by the very same starting image. The process of determining picture similarity is comparing visual information to evaluate how similar it is. Based on the input, it finds good matches and presents the proportion percent exceptional matches between the photos. It compares the supplied input to calculate the similarity measure. For decades, picture resemblance has been a fundamental problem in the fields of object recognition.When two photos are compared, Image Similarity generates a result that represents how physically similar they are. The measure of comparison of the two photographs is given a numerical number in this test. The similarity score between two photos ranges from 0 to 1 respectively.We have proposed a solution using SIFT & ORB Feature Matching

The interplay between grape ripening and weather anomalies in Northern Italy – A modelling exercise

Current climate change is increasing inter- and intra-annual variability in atmospheric conditions leading to grapevine phenological shifts as well as altered grape ripening and composition at ripeness.This study aims to i) detect weather anomalies within a long-term time series, ii) model grape ripening revealing altered traits in time to target specific ripeness thresholds for four Vitis vinifera cultivars, and iii) establish empirical relationships between ripening and weather anomalies with forecasting purposes. The Day of the Year (DOY) to reach specific grape ripeness targets was determined from time series of sugar concentrations, total acidity and pH collected from a private company in the period 2009–2021 in North-Eastern Italy. Non-linear regression models were fitted over a time series of ripening parameters on a calendar time basis and assessed for modelling efficiency (EF) and error of prediction (RMSE) in four grapevine cultivars (Merlot, Cabernet-Sauvignon, Glera and Garganega). For each vintage and cultivar, advances or delays in DOY to target specified ripeness thresholds were assessed with respect to the average ripening dynamics. A thirteen years’ long meteorological series monitored at a ground weather station using hourly air temperature and rainfall data was analysed. Climate statistics were obtained and for each time interval (month, bimester) weather anomalies were identified. A linear regression analysis was performed to assess correlations between ripening and weather anomalies. For each cultivar, ripeness advances or delays expressed in the number of days to target the specific ripening threshold were assessed in relation to registered weather anomalies and the specific reference time interval in the vintage. Precipitation of the warmest month and temperature anomalies during late spring (May–June) and during the warmest month (August) we found to be important to understanding the effect of climate change on sugar ripeness. Maximum and minimum temperatures of the May–June bimester and maximum temperatures of the warmest month best correlate with altered total acidity evolution and pH increment during the ripening process. A new modelling framework is presented using historical data that supports management decisions by better understanding past impacts and forecasting for the future.

Assessment of Explosion Safety Status within the Area of an LNG Terminal in a Function of Selected Parameters

This paper examines the issues of designing optimization tasks with the objective of ensuring the safety and continuation of transportation processes. Modelling the processes that are a consequence of a breakdown is a crucial issue enabling an increase of safety at selected stages of transport. This paper elaborates on the matter of modelling hazardous situations resulting from an uncontrolled LNG release due to a crash or damage to a ship’s hull. This paper demonstrates subsequent stages of modelling along with theoretical assumptions and finally it presents the results of simulation calculations for various scenarios of LNG releases. The article shows the complexity of modelling at a time when variable atmospheric conditions occur, which hinder the planning of rescue operations in the event of an uncontrolled LNG release into the atmosphere. It needs to be remembered that making decisions in critical situations and developing proper procedures at a time when people’s lives are at risk or in the face of an environmental pollution incident constitutes one of the most significant components of effective management in transport. Two LNG release scenarios are presented in this article: catastrophic rupture and leak, for which danger zone dimensions were calculated. Simulations were conducted with the use of a tool called Phast ver. 8.23 for LNG. Calculations were made in a function of variable weather conditions and for two values of Pasquill coefficients.

How useful are crowdsourced air temperature observations? An assessment of Netatmo stations and quality control schemes over the United Kingdom

AbstractObservations of the real‐time state of the atmosphere are required in order to initialize numerical weather prediction (NWP) models. As NWP resolution improves, more observations are needed, to better capture regional variations in atmospheric conditions. In particular, surface observations are necessary to reflect conditions experienced on the surface. One proposed opportunity to increase the number of surface observations available for assimilation into NWP is to crowdsource the data from home weather stations. This study investigates the outdoor air temperature measurements made by Netatmo home weather stations, through validation against a calibrated laboratory chamber and by evaluating quality control schemes that are applied to a UK‐wide network of Netatmo stations. In a series of controlled lab experiments, it was found that the Netatmo temperature sensor was accurate to 0.3°C. The response to fluctuations in temperature is lagged, with τ (the time taken for 63% of the change to be measured) calculated as 12.7 min for a near‐instantaneous decrease in temperature. Netatmo temperature observations were compared with Met Office MIDAS hourly weather observations. A warm bias in excess of 1°C was present in the Netatmo temperature observations, which was lessened by the three quality control schemes tested, but still in excess of 0.5°C. Hence, Netatmo temperature measurements have potential to be assimilated in NWP in the United Kingdom, but work is required to find a suitable agreed quality control scheme to filter out anomalous observations in the United Kingdom.

On the Redox-Activity and Health-Effects of Atmospheric Primary and Secondary Aerosol: Phenomenology

The RHAPS (Redox-Activity And Health-Effects Of Atmospheric Primary And Secondary Aerosol) project was launched in 2019 with the major objective of identifying specific properties of the fine atmospheric aerosol from combustion sources that are responsible for toxicological effects and can be used as new metrics for health-related outdoor pollution studies. In this paper, we present the overall methodology of RHAPS and introduce the phenomenology and the first data observed. A comprehensive physico-chemical aerosol characterization has been achieved by means of high-time resolution measurements (e.g., number size distributions, refractory chemical components, elemental composition) and low-time resolution analyses (e.g., oxidative potential, toxicological assays, chemical composition). Preliminary results indicate that, at the real atmospheric conditions observed (i.e., daily PM1 from less than 4 to more than 50 μg m−3), high/low mass concentrations of PM1, as well as black carbon (BC) and water soluble Oxidative Potential (WSOP,) do not necessarily translate into high/low toxicity. Notably, these findings were observed during a variety of atmospheric conditions and aerosol properties and with different toxicological assessments. Findings suggest a higher complexity in the relations observed between atmospheric aerosol and toxicological endpoints that go beyond the currently used PM1 metrics. Finally, we provide an outlook to companion papers where data will be analyzed in more detail, with the focus on source apportionment of PM1 and the role of source emissions on aerosol toxicity, the OP as a predictive variable for PM1 toxicity, and the related role of SOA possessing redox-active capacity, exposure-response relationships for PM1, and air quality models to forecast PM1 toxicity.