Journal articles: 'Air masses Mathematical models'

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Gomes, Francileni Pompeu, Osvaldo Resende, Elisabete Piancó de Sousa, Juliana Aparecida Célia, and Kênia Borges de Oliveira. "Application of Mathematical Models and Thermodynamic Properties in the Drying of Jambu Leaves." Agriculture 12, no. 8 (August 18, 2022): 1252. http://dx.doi.org/10.3390/agriculture12081252.

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Jambu is a vegetable originally from the northern region of Brazil, has bioactive properties, being little explored by other regions, due to its high peresivity. And one of the methods to increase the shelf life of plant products is the removal of water. The objective of this work was to evaluate the drying kinetics of jambu leaf mass. Two treatments were carried out: The mass of fresh jambu leaves and the mass of fresh jambu leaves with the addition of drying foam, both submitted in an oven with forced air circulation at temperatures (50, 60 and 70 °C and thickness of 1.0 cm). The proximate composition of the materials was performed before and after drying. Twelve mathematical models were tested on drying kinetics data and thermodynamic properties were calculated. The parameters of the proximate composition for the mass of leaves and foam after drying were: Moisture content of (2 to 7%), ash content of (13 to 17%), protein content of (22 to 30%), lipids of (0.6 to 4%) and total titratable acidity (0.20 to 0.28%) of tartaric acid. The models that best fit the experimental data to describe the drying kinetics of jambu masses were: Wang & Singh. The use of foam mat presented higher values of effective diffusion coefficient and activation energy and lower values of enthalpy and entropy, reducing the drying time.

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Koval, Oleksandr. "SEASON DYNAMICS OF THE TEMPERATURE MODE OF BILOOZERSKYI MASSIVE OF RIVNE NATURAL RESERVE." GEOGRAPHY AND TOURISM, no. 54 (2019): 83–92. http://dx.doi.org/10.17721/2308-135x.2019.54.83-92.

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Purpose. The purpose of the research is to analyze the temperature regime of the Biloozerskyi massive of Rivne Nature Reserve according to the data of the three nearest meteorological stations and to identify its dynamics and patterns. Methods. In the work are used the results of observations of the air temperature of the meteorological stations in Sarny, Lyubeshiv and Manevychi for the period of 2006-2018, which are freely available on the Internet: http://www.pogodaiklimat.ru. Climatological information was analyzed during the research. Mathematical statistics calculations have been applied to determine the decade air temperatures. Techniques for building graphical models (Excel software) for the annual course of air temperature were used. Graphic models set the date of transition of air temperature across thresholds, the length of periods with different temperatures and the length of periods with winter thaw and high summer temperatures. The work is based on statistical, analytical, comparative, graphic and descriptive research methods. Results. The daily, ten-day, monthly, annual, and long-term values of air temperature were analyzed and the date of steady transition of average daily air temperature across thresholds was established. The dynamics of starting and ending dates of different seasons and their duration are investigated. It is established that the duration of different seasons varies and varies significantly over the years. The cold season covers the winter and is characterized by alternation of cold and warm periods: the flow of cold air masses is accompanied by a decrease in air temperature, and the flow of warm air masses is accompanied by short or long thaws. In general, most of the winter is thawed days. The warm season covers spring, summer and autumn. Spring is the least longest and most dynamic period of the year. According to the peculiarities of the development of circulation processes and the rate of change of air temperature, spring and autumn are divided into several periods. The division of the transitional seasons into periods is conditioned by the beginning and the end of the warm period and the periods of vegetation and active vegetation. Summer is the longest period of the year. The summer is characterized by periods with high temperatures, when maximum temperatures are recorded in different grades. Scientific novelty. The research of the temperature regime of the protected area under the conditions of modern climate change is carried out. The dates of beginning and ending of different seasons, their duration and dynamics are established and regularities are formed. The practical significance. The materials of the research can be used for further meteorological research of nature reserves, for the needs of recreation, agrometeorology and in the educational process in the study of regional disciplines.

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Тиняков, Дмитрий Васильевич, and Виктор Иванович Рябков. "МЕТОД ПОПЕРЕДНЬОГО ФОРМУВАННЯ ОСНОВНИХ ПАРАМЕТРІВ ПІД ЧАС ГЛИБОКИХ МОДІФІКАЦІЙНИХ ЗМІН У ЛІТАКАХ ТРАНСПОРТНОЇ КАТЕГОРІЇ." Aerospace technic and technology, no. 7 (November 10, 2018): 62–67. http://dx.doi.org/10.32620/aktt.2018.7.09.

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The method of a preliminary development of main performances during deep variation in variants of a transport category aircraft, that is, when changing a wing area and a powerplant output, has been proposed. The main performance of any aircraft on the stage of its modifying is takeoff mass to, its value depends on structural members’ masses, in which modifications changes are present. The method is based on the com-parative evaluation of take-off mass increments of a basic aircraft and it’s variant. That allows qualitatively and quantitatively to evaluate the specific value of the take-off mass increment of an airplane variant depending on engineering and economical requirements changes. Also, it is obvious that changes in the combination of performances their changes in the process of an aircraft variant creation, move the solution of an existence equation at new point, which corresponds to a new takeoff mass. The analysis of the method was implemented on the example of the regional passenger aircraft variant with two turboprop engines. The method of a preliminary development of main performances of a transport category aircraft subject to deep modification, i.e. when changing a wing area or a powerplant output, is proposed. The mathematical model for the estimation of the takeoff mass increment, depending on requirement groups realized in modifications, is developed by using the models of calculation of required mass (due to change of modification) and available mass (constant for a base variant). Statistical equations for the preliminary estimation of a takeoff mass increment, that create the relationship between the constituent masses and the takeoff mass for a regional aircraft, are used. For middle-range and long-range airplanes an adjustment is needed. The proposed method and the mathematical models allow at a preliminary designing stage of an airplane variant not only typical required quantitative change in structure, but the necessary changes of a wing area and a powerplant output to satisfy the required engineering and economical requirements, which aircraft and air-lines’ markets dictate.

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Mehrotra, Utkarsh, Arthur Brazzle, Michael McKeown, and Douglas C. Hopkins. "Lithium Battery Cell Level Fusing with Aluminum Heavy Wire Bonds." International Symposium on Microelectronics 2020, no. 1 (September 1, 2020): 000009–14. http://dx.doi.org/10.4071/2380-4505-2020.1.000009.

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Abstract Aluminum heavy wire bonds interconnects are a potential alternative to laser or resistance welded bus bars due to its ease of manufacturability, long term reliability and low cost for battery banks. They can also be utilized as a fault protection solution in case of a surge current, dead short, etc, and to isolate a bad cell preventing synchronous failure. Typically, the current-carrying capability of a wire is estimated using standard data generated by testing in free air. However, a deviation in the capacity limits can occur due to the proximity of interconnect to larger thermal masses and different heat extraction techniques found in present day lithium battery packs; e.g., fluid channel cooling, encapsulated wires, etc. The cylindrical cell cathode, anode, and the busbar material constitute a large thermal mass to increase the fusing current in wire bonds above conventional levels. To better predict and design the interconnects advanced and system-specific models should be developed. This paper presents a new mathematical approach which includes the effect of convective cooling inside the battery pack to do an early step estimation of the current handling capacity and fusing time of different diameter wires. The paper also presents a finite element model that includes the impact of boundary conditions, wire length and wire diameter on steady-state current handling capacity of 99.99 % Al wire. Both steady-state and transient simulations were performed to estimate fusing times at different time rated conditions. The paper concludes by providing new curve-fit patterns to give future battery pack designers further insight aiding new designs.

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Dudakova, Dina, Vladimir Anokhin, Mikhail Dudakov, and Andrey Ronzhin. "On Theoretical Foundations of Aerolimnology: Study of Fresh Water Bodies and Coastal Territories Using Air Robot Equipment." Informatics and Automation 21, no. 6 (November 24, 2022): 1359–93. http://dx.doi.org/10.15622/ia.21.6.10.

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The integration of the methodological basis of several different sciences in interdisciplinary research is a characteristic feature of new mechanisms for solving modern applied problems. The emerging theoretical foundations of aerolimnology, as a new scientific direction, are considered from the point of view of the contribution of three key sciences to it: limnology, informatics and robotics. Classifications of methods and approaches of limnological research, airborne robotic means, and information technologies that are promising for solving problems in the field of aerolimnology are given. The task of the scientific direction of aerolimnology is formulated as the study of the possibilities and limitations of combined methods of remote sensory measurement, robotic sampling and analytical study of the parameters of freshwater ecosystems to monitor and predict the dynamics of their development. Among the main areas of aerolimnological research, the following are distinguished: the construction of orthophotomaps and photogrammetric spatial models of the bottom topography and individual elements of the bottom landscape and coastal zone of various scales; geological and geophysical mapping of the underwater part of the coastal zone; the study of phytoplankton, in particular, the "bloom" of water caused by cyanobacteria; study of distribution and migration of large representatives of hydrofauna; study of temperature fields and processes of redistribution of water masses. The limitations imposed on the use of unmanned aerial vehicles (UAVs) in sampling and monitoring coastal water areas are discussed, primarily weather-climatic, temporal, spatial, and technical. The advantage of using unmanned aerial vehicles in aerolimnology is justified by an increase in the speed of data acquisition, the possibility of approaching hard-to-reach and territorially remote objects, and a decrease in the influence of the human factor. The scientific novelty of the presented research consists in an attempt to integrate interdisciplinary knowledge when using unmanned aerial vehicles and processing the obtained data based on artificial intelligence technologies in the study of limnological objects and processes. The important role of geoinformation systems is noted and examples of maps of shore typification and geomorphology of Lake Ladoga are given, posted on the website of the Center for the Collective Use of Scientific Equipment "North-Western Center for Monitoring and Forecasting the Development of Territories" of the St. Petersburg Federal Research Center of the Russian Academy of Sciences. The main stages of the methodology for conducting aerolimnological studies using interdisciplinary approaches based on limnology, informatics and robotic tools operating in different environments are considered.

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Yokota, Shuichiro. "Mathematical models of weathering process in jointed rock masses." Journal of the Geological Society of Japan 98, no. 2 (1992): 155–63. http://dx.doi.org/10.5575/geosoc.98.155.

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Gorobtsov, A. S., M. V. Lyashenko, N. S. Sokolov-Dobrev, V. V. Shekhovtsov, P. V. Potapov, E. V. Klementyev, and A. A. Dolotov. "Mathematical model of test bench." Izvestiya MGTU MAMI 10, no. 2 (June 15, 2016): 20–25. http://dx.doi.org/10.17816/2074-0530-66903.

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The description of multifunctional test bench construction to determine the basic operational characteristics of transmissions of automobiles and trucks designed in Volgograd State Technical University is provided. The description of its mathematical model created on the basis of the spatial dynamic schema is given and the results of calculation of test bench mass and inertia parameters are provided. The models of moving masses are the masses of transmission rotating elements, which transmit torque, transmission housing, test bench frame, that consists of two subframes, two hubs, DinaPack loading device, including a hydraulic machine. The values of parts inertia moments and stiffness of its joints are obtained by DASP software package and SolidWorks 3D CAD system. On the first stage to carry out the simulation capabilities at various loading conditions and forecast their results without a long-term field tests, on the basis of the structural scheme of test bench the flat dynamic model was created, which besides the data on composition and communication of the masses, contains data on elastic, inertial and dissipative parameters of its elements. On the next stage the spatial structural test bench scheme was created, on the basis of which in “Universal mechanism” program the spatial dynamic model was made. The dynamic model of test bench includes 31 inertial masses influenced by linear, contact, bipolar and special forces. To check the adequacy of the created model at the initial stage the calculation of fundamental frequencies of its masses in the range from 0 to 10000 Hz was made. The comparison of its values with the results of processing of experimental digital oscillograms of test bench masses oscillations showed sufficient for the solution of engineering problems convergence of results.

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Louie, A. H., and R. C. Pierce. "Mathematical models of human exposure to air pollutants." Mathematical and Computer Modelling 10, no. 1 (1988): 49–64. http://dx.doi.org/10.1016/0895-7177(88)90121-5.

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Purwanto, Burhan Eko, Icha Jusmalisa, Indah Permata Sari, Agus Jatmiko, and Andika Eko Pasetiyo. "Learning Models to Improved Mathematical Communication Skills." Desimal: Jurnal Matematika 3, no. 1 (January 23, 2020): 7–16. http://dx.doi.org/10.24042/djm.v3i1.5650.

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The problem faced by students in slow learning is in terms of communication. The use of Auditory, Intellectually, Repetition (AIR) and Cooperative Think Pair Share (TPS) types is needed to help students communicate mathematically in expressing mathematical ideas. This study aims to determine whether or not there are differences in mathematical communication skills of students using the Auditory, Intellectually, Repetition (AIR) learning model with students who use Think Pair Share (TPS) Cooperative learning models. This research uses a quantitative approach using the Quasi Experiment method. The research design is in the form of posttest only, non-equivalent group design. Testing data using the T test with Independent Samples T-Test. Based on the results of hypothesis testing obtained p-value> α 0.05. So it was concluded that there were indications of differences between Auditory, Intellectually, Repetition (AIR) learning models with (TPS) Cooperative learning models and superior (AIR) learning models compared to Cooperative learning models of (TPS) Type in influencing students' mathematical communication skills.

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Zadhesh, Jamal, and Abbas Majdi. "MATHEMATICAL DETERMINATION OF ROCK JOINTS MORPHOLOGICAL PROFILE." Rudarsko-geološko-naftni zbornik 37, no. 5 (2022): 117–31. http://dx.doi.org/10.17794/rgn.2022.5.10.

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Determining the geometric or morphology and mechanical properties of joints and geomechanics of intact rock is a vitally important issue in predicting the behaviour of structures built inside or on rock masses. The joint morphology is significant because it affects the strength of the rock mass and controls the stability of the structures related to the rock masses. Until recently, joint morphology was introduced in a simple form which brought about models that are far from the inherent state of a rock joint. The work presented in this research introduces a new model to represent rock joint morphology which is very close to reality. For this research, Sarchawa marble mine joint systems are studied. According to this research, the morphology of each rock joint can be expressed as a mathematical equation. Using the output of this research, we can see a more realistic view of the rock masses. As a result, we can have better designs for structures correlated to rock masses, making the result better and more reliable.

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Ding, Yuting, Yiming Hu, Jianyou Zhang, Fei Lu, and Lin Liu. "Mathematical Models’ Establishment of Hot-Air Drying forSpratelloides gracilis." Journal of Aquatic Food Product Technology 21, no. 4 (July 2012): 380–92. http://dx.doi.org/10.1080/10498850.2011.604901.

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Cooper, W. W., H. Hemphill, Z. Huang, S. Li, V. Lelas, and D. W. Sullivan. "Survey of mathematical programming models in air pollution management." European Journal of Operational Research 96, no. 1 (January 1997): 1–35. http://dx.doi.org/10.1016/s0377-2217(97)86747-1.

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Qin, Yuan, Xu Yatao, and Song Anqi. "Heuristic Research on Mathematical Models of Air Refueling Support." Procedia Environmental Sciences 10 (2011): 117–21. http://dx.doi.org/10.1016/j.proenv.2011.09.021.

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Qin, Yuan, Xu Yatao, and Song Anqi. "Heuristic Research on Mathematical Models of Air Refueling Support." Procedia Environmental Sciences 10 (2011): 748–52. http://dx.doi.org/10.1016/j.proenv.2011.09.121.

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Shon, Z. H., S. Madronich, S. K. Song, F. M. Flocke, D. J. Knapp, R. S. Anderson, R. E. Shetter, C. A. Cantrell, S. R. Hall, and X. Tie. "Characteristics of the NO-NO2-O3 system in different chemical regimes during the MIRAGE-Mex field campaign." Atmospheric Chemistry and Physics 8, no. 23 (December 9, 2008): 7153–64. http://dx.doi.org/10.5194/acp-8-7153-2008.

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Abstract. The NO-NO2 system was analyzed in different chemical regimes/air masses based on observations of reactive nitrogen species and peroxy radicals made during the intensive field campaign MIRAGE-Mex (4 to 29 March 2006). The air masses were categorized into 5 groups based on combinations of macroscopic observations, geographical location, meteorological parameters, models, and observations of trace gases: boundary layer (labeled as "BL"), biomass burning ("BB"), free troposphere (continental, "FTCO" and marine, "FTMA"), and Tula industrial complex ("TIC"). In general, NO2/NO ratios in different air masses are near photostationary state. Analysis of this ratio can be useful for testing current understanding of tropospheric chemistry. The ozone production efficiency (OPE) for the 5 air mass categories ranged from 4.5 (TIC) to 8.5 (FTMA), consistent with photochemical aging of air masses exiting the Mexico City Metropolitan Area.

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Md Ali, Mohd Adli, Mohd Radhwan Abidin, Nik Arsyad Nik Muhamad Affendi, Hafidzul Abdullah, Daaniyal R. Rosman, Nu'man Barud'din, Faiz Kemi, and Farid Hayati. "CLASSIFICATION OF CHEST RADIOGRAPHS USING NOVEL ANOMALOUS SALIENCY MAP AND DEEP CONVOLUTIONAL NEURAL NETWORK." IIUM Engineering Journal 22, no. 2 (July 4, 2021): 234–48. http://dx.doi.org/10.31436/iiumej.v22i2.1752.

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The rapid advancement in pattern recognition via the deep learning method has made it possible to develop an autonomous medical image classification system. This system has proven robust and accurate in classifying most pathological features found in a medical image, such as airspace opacity, mass, and broken bone. Conventionally, this system takes routine medical images with minimum pre-processing as the model's input; in this research, we investigate if saliency maps can be an alternative model input. Recent research has shown that saliency maps' application increases deep learning model performance in image classification, object localization, and segmentation. However, conventional bottom-up saliency map algorithms regularly failed to localize salient or pathological anomalies in medical images. This failure is because most medical images are homogenous, lacking color, and contrast variant. Therefore, we also introduce the Xenafas algorithm in this paper. The algorithm creates a new kind of anomalous saliency map called the Intensity Probability Mapping and Weighted Intensity Probability Mapping. We tested the proposed saliency maps on five deep learning models based on common convolutional neural network architecture. The result of this experiment showed that using the proposed saliency map over regular radiograph chest images increases the sensitivity of most models in identifying images with air space opacities. Using the Grad-CAM algorithm, we showed how the proposed saliency map shifted the model attention to the relevant region in chest radiograph images. While in the qualitative study, it was found that the proposed saliency map regularly highlights anomalous features, including foreign objects and cardiomegaly. However, it is inconsistent in highlighting masses and nodules. ABSTRAK: Perkembangan pesat sistem pengecaman corak menggunakan kaedah pembelajaran mendalam membolehkan penghasilan sistem klasifikasi gambar perubatan secara automatik. Sistem ini berupaya menilai secara tepat jika terdapat tanda-tanda patologi di dalam gambar perubatan seperti kelegapan ruang udara, jisim dan tulang patah. Kebiasaannya, sistem ini akan mengambil gambar perubatan dengan pra-pemprosesan minimum sebagai input. Kajian ini adalah tentang potensi peta salien dapat dijadikan sebagai model input alternatif. Ini kerana kajian terkini telah menunjukkan penggunaan peta salien dapat meningkatkan prestasi model pembelajaran mendalam dalam pengklasifikasian gambar, pengesanan objek, dan segmentasi gambar. Walau bagaimanapun, sistem konvensional algoritma peta salien jenis bawah-ke-atas kebiasaannya gagal mengesan salien atau anomali patologi dalam gambar-gambar perubatan. Kegagalan ini disebabkan oleh sifat gambar perubatan yang homogen, kurang variasi warna dan kontras. Oleh itu, kajian ini memperkenalkan algoritma Xenafas yang menghasilkan dua jenis pemetaan saliensi anomali iaitu Pemetaan Kebarangkalian Keamatan dan Pemetaan Kebarangkalian Keamatan Pemberat. Kajian dibuat pada peta salien yang dicadangkan iaitu pada lima model pembelajaran mendalam berdasarkan seni bina rangkaian neural konvolusi yang sama. Dapatan kajian menunjukkan dengan menggunakan peta salien atas gambar-gambar radiografi dada tetap membantu kesensitifan kebanyakan model dalam mengidentifikasi gambar-gambar dengan kelegapan ruang udara. Dengan menggunakan algoritma Grad-CAM, peta salien yang dicadangkan ini mampu mengalih fokus model kepada kawasan yang relevan kepada gambar radiografi dada. Sementara itu, kajian kualitatif ini juga menunjukkan algoritma yang dicadangkan mampu memberi ciri anomali, termasuk objek asing dan kardiomegali. Walau bagaimanapun, ianya tidak konsisten dalam menjelaskan berat dan nodul.

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Azouz, Naoufel, Said Chaabani, Jean Lerbet, and Azgal Abichou. "Computation of the Added Masses of an Unconventional Airship." Journal of Applied Mathematics 2012 (2012): 1–19. http://dx.doi.org/10.1155/2012/714627.

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This paper presents a modelling of an unmanned airship. We are studying a quadrotor flying wing. The modelling of this airship includes an aerodynamic study. A special focus is done on the computation of the added masses. Considering that the velocity potential of the air surrounding the airship obeys the Laplace's equation, the added masses matrix will be determined by means of the velocity potential flow theory. Typically, when the shape of the careen is quite different from that of an ellipsoid, designers in preprocessing prefer to avoid complications arising from mathematical analysis of the velocity potential. They use either complete numerical studies, or geometric approximation methods, although these methods can give relatively large differences compared to experimental measurements performed on the airship at the time of its completion. We tried to develop here as far as possible the mathematical analysis of the velocity potential flow of this unconventional shape using certain assumptions. The shape of the careen is assumed to be an elliptic cone. To retrieve the velocity potential shapes, we use the spheroconal coordinates. This leads to the Lamé's equations. The whole system of equations governing the interaction air-structure, including the boundary conditions, is solved in an analytical setting.

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Alvarez, Benjamin Louis, and Jérémy Faupin. "Scattering theory for mathematical models of the weak interaction." Reviews in Mathematical Physics 32, no. 01 (August 8, 2019): 2050002. http://dx.doi.org/10.1142/s0129055x20500026.

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We consider mathematical models of the weak decay of the vector bosons [Formula: see text] into leptons. The free quantum field Hamiltonian is perturbed by an interaction term from the standard model of particle physics. After the introduction of high energy and spatial cut-offs, the total quantum Hamiltonian defines a self-adjoint operator on a tensor product of Fock spaces. We study the scattering theory for such models. First, the masses of the neutrinos are supposed to be positive: for all values of the coupling constant, we prove asymptotic completeness of the wave operators. In a second model, neutrinos are treated as massless particles and we consider a simpler interaction Hamiltonian: for small enough values of the coupling constant, we prove again asymptotic completeness, using singular Mourre’s theory, suitable propagation estimates and the conservation of the difference of some number operators.

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Zadoiannyi, O., and Y. Yevdokymenko. "THEORETICAL ANALYSIS OF MEMBRANE AIR DEHUMIDIFICATION IN AIR CONDITIONING SYSTEMS." Innovative Solution in Modern Science 4, no. 48 (June 30, 2021): 33. http://dx.doi.org/10.26886/2414-634x.4(48)2021.3.

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The paper presents a simulation of the process of removing moisture from the air in air conditioning systems using construction vapor-permeable membranes. The existing classical physical and mathematical models are considered and analyzed. Based on the analysis of classical models, a schematic and corresponding theoretical mathematical model of air dehumidification with a semipermeable building membrane with certain characteristics for possibilities of use in air conditioning systems is developed and presented. The data of calculations of moisture release from air for the developed model are given. As a result of analytical researches the correct data for possible use in air conditioning systems are received. Key words: air conditioning systems, air dehumidification, semipermeable membrane, permeability, membrane air dehumidification, convective flow, diffusion flow, moisture permeability.

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Timmerman, D., F. De Smet, J. De Brabanter, C. Van Holsbeke, K. Jermy, Y. Moreau, T. Bourne, and I. Vergote. "OC118: Mathematical models to evaluate ovarian masses?can they beat an expert operator?" Ultrasound in Obstetrics and Gynecology 22, S1 (2003): 33. http://dx.doi.org/10.1002/uog.329.

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Usubamatov, R., and T. Zhumaev. "Inertial Forces Acting on a Propeller of Aircraft." Open Aerospace Engineering Journal 7, no. 1 (August 29, 2018): 1–13. http://dx.doi.org/10.2174/1874146001807010001.

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Background:Aerospace vehicles use propellers with the different design that possess gyroscopic properties. Recent investigations in the area of gyroscope theory have demonstrated that the gyroscope properties are based on the action of the centrifugal, common inertial, and Coriolis forces of the distributed mass elements of the spinning rotor, as well as the change in the angular momentum.Objective:The combined action of the interrelated inertial forces on the propellers presents the interests for the design of the blades. The objective of the manuscript is the derivation of mathematical models for the inertial torques acting on the spinning propellers that enable computing the stresses of the blades and increasing their reliability.Method:The inertial torques generated by the masses of the rotating blades acting on the propellers are represented by mathematical models in L. Euler’s form.Results:The inertial torques are generated by the several inertial forces of the propeller’s blades and hub and manifested the fluctuation of the variable resistance and precession torques acting around different axes of the propeller. Derived mathematical models for the inertial torques are new and should be used for the computing forces and stresses acting on the propellers of the aircraft.Conclusion:The mathematical models for the torques acting on the propellers consider the several inertial forces of the rotating masses that manifest their gyroscope properties. Derived mathematical models for inertial torques enable for computing the stresses of the aircraft propellers and clearly demonstrate the physical principles and origin of the acting inertial forces.

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Ott, Wayne R. "Mathematical Models for Predicting Indoor Air Quality from Smoking Activity." Environmental Health Perspectives 107 (May 1999): 375. http://dx.doi.org/10.2307/3434430.

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Ott, W. R. "Mathematical models for predicting indoor air quality from smoking activity." Environmental Health Perspectives 107, suppl 2 (May 1999): 375–81. http://dx.doi.org/10.1289/ehp.99107s2375.

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Mitici, Mihaela, and Henk A. P. Blom. "Mathematical Models for Air Traffic Conflict and Collision Probability Estimation." IEEE Transactions on Intelligent Transportation Systems 20, no. 3 (March 2019): 1052–68. http://dx.doi.org/10.1109/tits.2018.2839344.

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Nicas, Mark. "Using mathematical models to estimate exposure to workplace air contaminants." Chemical Health and Safety 10, no. 1 (January 2003): 14–21. http://dx.doi.org/10.1016/s1074-9098(02)00413-6.

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Zandieh, M., and S. Molla-Alizadeh-Zavardehi. "Synchronizing production and air transportation scheduling using mathematical programming models." Journal of Computational and Applied Mathematics 230, no. 2 (August 2009): 546–58. http://dx.doi.org/10.1016/j.cam.2008.12.022.

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Zhukovskiy, M. E., V. S. Zakharov, and S. V. Podolyako. "Mathematical Models of Ionization of Air Plasma by Electron Flux." Mathematical Models and Computer Simulations 14, no. 6 (November 3, 2022): 984–94. http://dx.doi.org/10.1134/s2070048222060199.

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Usubamatov, Ryspek, and Albina Omorova. "A Mathematical Model for Top Nutation Based on Inertial Forces of Distributed Masses." Mathematical Problems in Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/6132891.

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The main property of gyroscopic devices is maintaining the axis of a spinning rotor, a mathematical model formulated on the principle of the change in the angular momentum. This principle is used for mathematical modeling of the motions of a top at known publications. Nevertheless, practical tests of gyroscopic devices do not correspond to this analytical approach. Recent investigations have demonstrated that the origin of gyroscope properties is more complex than that represented in known publications. The applied torque on a gyroscope produces internal torques of the spinning rotor based on the action of the several inertial forces. These forces are the centrifugal, Coriolis, and common inertial forces as well as the change in the angular momentum generated by the mass elements and center-mass of the spinning rotor. The action of these torques manifests itself in the resistance and precession torques of the gyroscopic devices. These inertial torques act simultaneously and interdependently around two axes and represent the fundamental principles of the gyroscope theory. The new inertial torques enable deriving mathematical models for the motions of well-known top that is the simplest form of gyroscopic devices. The novelty of the work is mathematical models for the motions of the top based on action of eight inertial forces acting around its two axes. The obtained mathematical models for the top nutation and self-stabilization are represented in terms of machine dynamics and vibration analysis. The new analytical approach for motions of the well-balanced top and top with eccentricity of the center-mass definitely responds to the practical results.

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Aguirre-Mendoza, Andres M., Sebastián Oyuela, Héctor G. Espinoza-Román, Oscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, and Duban A. Paternina-Verona. "2D CFD Modeling of Rapid Water Filling with Air Valves Using OpenFOAM." Water 13, no. 21 (November 4, 2021): 3104. http://dx.doi.org/10.3390/w13213104.

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The rapid filling process in pressurized pipelines has been extensively studied using mathematical models. On the other hand, the application of computational fluid dynamics models has emerged during the last decade, which considers the development of CFD models that simulate the filling of pipes with entrapped air, and without air expulsion. Currently, studies of CFD models representing rapid filling in pipes with entrapped air and with air expulsion are scarce in the literature. In this paper, a two-dimensional model is developed using OpenFOAM software to evaluate the hydraulic performance of the rapid filling process in a hydraulic installation with an air valve, considering different air pocket sizes and pressure impulsion by means of a hydro-pneumatic tank. The two-dimensional CFD model captures the pressure evolution in the air pocket very well with respect to experimental and mathematical model results, and produces improved results with respect to existing mathematical models.

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Piotrowski, Jerzy Zbigniew, Anatoliy Stroy, and Marianna Olenets. "MATHEMATICAL MODEL OF THE THERMAL-AIR REGIME OF A VENTILATED ATTIC." Journal of Civil Engineering and Management 21, no. 6 (June 9, 2015): 710–19. http://dx.doi.org/10.3846/13923730.2014.893914.

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This paper presents the developed mathematical models that characterize the thermal-air regime of a ventilated attic in the summer and winter seasons. The relevance of the mathematical models was shown and examples of applying these models to solve some engineering problems were presented. Mathematical models can be used to analyze and evaluate changes in the temperature and heat flux (the radiant and convective component) along the air movement in the attic and to select the materials for the roof and floor, as well as for the calculation of ventilation for different climatic conditions.

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Kazaryan, Ruben, Peraskovya Andreeva, and Natalya Galaeva. "Organization of planning in transport construction." E3S Web of Conferences 157 (2020): 04006. http://dx.doi.org/10.1051/e3sconf/202015704006.

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Purpose. Development of methods and models of economic efficiency of the integrated use of various modes of transport in the interests of ensuring national security of the state. Methods. System analysis, logical-mathematical modeling, systems theory, economic-visual modeling, research methods of operations, economic and mathematical methods. Results. The paper discusses the need for the application of economic and mathematical models in the design of transport construction (model of “moving the earth masses”, linear programming model, design of the “red line” on the longitudinal profile, dynamic programming model). Conclusion. The difficult stage of the transition of economic and mathematical analysis from the verbal description of the system process to the elemental base of the mathematical apparatus. Most research models of operations are designed for single criteria. Economic and mathematical modeling allows the effect of “private optimization”.

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Koman, M. M. "Using the satellite images for the territory of Ukraine." Ukrainian hydrometeorological journal, no. 26 (December 22, 2020): 24–36. http://dx.doi.org/10.31481/uhmj.26.2020.02.

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The purpose of this article is to identify the wind direction and speed using the images from geostationary satellites and through application of two-dimensional wind vectors, the magnitude and direction of which corresponds to the speed and direction of cloud masses, on a satellite image. The results may be used for making a short-term forecast of dangerous weather events within the territory of Ukraine. To make the technique work, it is necessary to select cloud areas on a satellite image using the threshold method. Then, based on the brightness temperature distribution between two tracking modules (parts of an image based on which two consecutive satellite images are compared), the maximum correlation coefficient for infrared brightness temperature is to be determined. The coefficient corresponds to the movement of cloud masses and sets the beginning and end of the wind direction vector. To determine the optimum application of the technique for the territory of Ukraine, the analysis of accuracy of tracking modules of different sizes was also performed. The analysis revealed that the accuracy of determining the wind vector direction depends on the tracking module size: the larger it is, the more accurate is the direction vector found, but given that the time interval between images is 15 minutes, the optimum algorithm to be used in Ukraine is the one with 5x5 pixel tracking module. The technique performance was also compared with the data of ICON and GFS forecast models. The results of the applied algorithm showed that the direction of air masses was more reliable than the data retrieved from the above-mentioned forecast models, because the algorithm analyzes the real-time movement of air masses while the forecast models assess the formation and movement of air masses in advance (with an interval of several hours up to dozens of hours). Numerical wind speed forecast of ICON and GFS models is more accurate, because the algorithm determines the wind speed based on the movement of cloud masses on satellite images whereas the forecast models consider several factors (pressure fields, development and subsequent evolution of cyclones, anticyclones, geographical characteristics etc.) which makes them more realistic.

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Pushkov, S. G., L. L. Lovitsky, O. Y. Gorshkova, and I. V. Malakhova. "Aerodynamic Errors Mathematical Modeling in Air Data Systems Estimation Technology in Flight Tests Using Satellite Navigation Systems." Mekhatronika, Avtomatizatsiya, Upravlenie 22, no. 5 (May 17, 2021): 272–80. http://dx.doi.org/10.17587/mau.22.272-280.

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Problems of mathematical modeling of onboard air data systems errors are of paramount importance in pitot-static sources errors determination, air data systems evaluation in flight tests. The problems of development, identification and assessment of the mathematical models of errors adequacy acquire main importance in the modern technology of the air parameters true values determination, air data systems evaluation using satellite navigation systems, developed and applied in the practice of flight tests at JSC "FRI n.a. M. M. Gromov". This paper gives a general description of an air data systems estimation technology using satellite navigation systems. The principles of solving problems of aircraft data systems aerodynamic errors mathematical modeling are stated. The structure of mathematical models, factors of the aerodynamic errors, relationship of the solving problems of errors modeling within the framework of technology with a flight experiment plan are shown. Mathematical models parameters identification are based on a complex solving of the problems of a true air data parameters values and aerodynamic errors determination in flight tests. New results of mathematical modeling of errors in tests at high angles of attack in 2018 year of medium-range and short-range aircraft are presented. The results illustrate the technology effectiveness in solving the problems of flight tests at high angles of attack information support, aerodynamic errors modeling, air data systems estimation. The applied modeling methods make it possible to allocate in the mathematical models of pitot-static sources aerodynamic errors even the factors of very weak aerodynamic influence, comparable with the minimum pressure sensors instrumental errors.

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Susanto, Andi. "KEMAMPUAN PEMAHAMAN KONSEP MATEMATIS MODEL RECIPROCAL TEACHING (RT) DAN MODEL AIR AUDITORY INTELLECTUALY REPETITION (AIR)." Math Educa Journal 3, no. 2 (November 11, 2019): 219–30. http://dx.doi.org/10.15548/mej.v3i2.677.

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The purpose of this research was to determine the ability to understand the mathematical concepts of students taught by reciprocal teaching models with an intellectually repetition model in SMP N 6 Kota Solok. This type of research is a quasy experiment with a randomized control group only design. Test instruments the ability to understand mathematical concepts. Based on the test result obtained the average ability to understand the mathematical concepts of students by reciprocal teaching model 81,66 by auditory intellectually repetition model 77,75 and ordinary learning 73,91. Hypothesis testing indicated that the ability to understand the mathematical concepts of students by reciprocal teaching model and the auditory intellectually repetition model were higher than the ordinary learning model. Beside it, it was also concluded that there were difference in the ability to understand mathematical concepts with reciprocal teaching model and auditory intellectually repetition model.

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Kuzyshyn, A. Y., S. A. Kostritsia, Yu H. Sobolevska, and А. V. Batih. "World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages." Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, no. 4(94) (August 17, 2021): 25–42. http://dx.doi.org/10.15802/stp2021/245974.

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Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

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Evans, W. C. "Mathematical models for the dynamic response of continuous particulate air monitors." IEEE Transactions on Nuclear Science 48, no. 2 (April 2001): 202–18. http://dx.doi.org/10.1109/23.915366.

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Ryabova, G. O. "The Geminid meteor shower radiant: a mathematical model." Monthly Notices of the Royal Astronomical Society 507, no. 3 (August 9, 2021): 4481–86. http://dx.doi.org/10.1093/mnras/stab2286.

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ABSTRACT The origin of the Geminid meteoroid stream and its parent body the asteroid (3200) Phaethon is still under discussion. The observed bimodal activity profile of the Geminid shower agrees with a cometary scheme of the stream formation. We show that the radiant areas for meteors of different magnitudes may also be used to provide arguments supporting or undermining the cometary hypothesis. We used semi-analytic and numerical models of the stream. The resulting model radiants for meteors of various magnitudes (masses) have peculiar patterns that might be detected in a real shower.

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Durcansky, Peter. "COMPARISON OF MATHEMATICAL MODELS FOR HEAT EXCHANGERS OF UNCONVENTIONAL CHP UNITS." Acta Polytechnica 55, no. 4 (August 31, 2015): 223. http://dx.doi.org/10.14311/ap.2015.55.0223.

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An unconventional CHP unit with a hot air engine is designed as the primary energy source with fuel in the form of biomass. The heat source is a furnace designed for combustion of biomass, whether in the form of wood logs or pellets. The transport of energy generated by the biomass combustion to the working medium of a hot-air engine is ensured by a special heat exchanger connected to this resource. The correct operation of the hot-air engine is largely dependent on an appropriate design of the exchanger. The paper deals with the calculation of the heat exchanger for the applications mentioned, using criterion equations, and based on CFD simulations.

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Cai, Jin, Xiangwei Kong, and Mingzhu Yu. "Mathematical Modeling of Sintering Air Leakage through Holes." Energies 15, no. 12 (June 8, 2022): 4224. http://dx.doi.org/10.3390/en15124224.

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The air leakage in sintering machines affects the technological and economic indexes of the sintering process. It is of great significance to monitor and estimate the key areas. Mathematical models of sintering air leakage through holes in the steady-state process are given based on the fluid mechanics to predict the flow rate and effect on the key area. It was found that the hole model is the application of constant orifice outflow in the computation of sintering air leakage. The counter-flow bed model is suitable for predicting the flow rate through a complete break in sintering wind boxes. Furthermore, This paper proposes a new hole–bed generalized model to cover all the possible hole diameters for further high-precision application. The model connects the leakage hole diameter with the sintering process for the first time and establishes their coupling relationship. The pressure state in the sintering system depends on the ratio of the leakage hole area to the sintering bed area. The proposed fast estimation models are a step forward in developing more precise and powerful calculation tools to foresee the effects and consequences of sintering air leakage. It has a good prospect for reducing and replacing complex manual measurement and bringing some insight into the state of the art that could be improved in the future.

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Shodiev, J., and M. Azimov. "Mathematical modeling of truck movement in rough road conditions of agricultural area." IOP Conference Series: Earth and Environmental Science 1076, no. 1 (August 1, 2022): 012003. http://dx.doi.org/10.1088/1755-1315/1076/1/012003.

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Abstract The article presents the methods of modeling the horizontal and vertical movement of a small truck Labo. Using the Lagrange equation of the second type, mathematical models of the movement of a small truck Labo on uneven roads developed. The mathematical models developed by the Runge-Kutta-number method solved and the values of the horizontal and vertical oscillations, speeds of movement and the forces acting and acting on each wheel of the automobile found. On the given masses, the parameters of the automobile’s leaf springs and the depreciation part are determined.

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Li, Jiu Ru, Shu Ling Jia, Yan Wang, Xiang Peng Kong, and Ming Tao Xu. "Performance Evaluation of the Upside Air-Supply Bottom-Side Air-Return Air Distribution Mode." Advanced Materials Research 468-471 (February 2012): 2513–16. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.2513.

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It took the air-conditioned room as a object of study, and established indoor air flow three-dimensional physical and mathematical models on the basis of the two-equation turbulence model and wall-function. By the numerical simulation of two different forms of upside air-supply bottom-side air-return air distribution modes, indoor air temperature field, velocity field and molecular trace field were obtained, whereby we evaluated the ventilation characteristics of the two kinds of air distribution modes.

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42

Vaes, Evelien, Ranjit Manchanda, Rina Nir, Dror Nir, Harry Bleiberg, Philippe Autier, Usha Menon, and Annie Robert. "Mathematical Models to Discriminate Between Benign and Malignant Adnexal Masses: Potential Diagnostic Improvement Using Ovarian HistoScanning." International Journal of Gynecologic Cancer 21, no. 1 (2011): 35–43. http://dx.doi.org/10.1097/igc.0b013e3182000528.

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Purpose:Accurate preoperative clinical assessment of adnexal masses can optimize outcomes by ensuring appropriate and timely surgery. This article addresses whether a new technology, ovarian HistoScanning, has an additional diagnostic value in mathematical models developed for the differential diagnosis of adnexal masses.Patients and Methods:Transvaginal sonography-based morphological variables were obtained through blinded analysis of archived images in 199 women enrolled in a prospective study to assess the performance of ovarian HistoScanning. Logistic regression (LR) and neural network (NN) models including these variables and clinical and patient data along with the HistoScanning score (HSS) (range, 0-125; based on mathematical algorithms) were developed in a learning set (60% patients). The remaining 40% patients (evaluation set) were used to assess model performance.Results:Of all morphological and clinical variables tested, serum CA-125, presence of a solid component, and HSS were most significant and used to develop the LR model. The NN model included all variables. The novel variable, HSS, offered significant improvement in the LR and NN models' performance. The LR and NN models in an independent evaluation set were found to have area under the receiver operating characteristic curve = 0.97 (95% confidence interval [CI], 94-99) and 0.93 (95% CI, 88-98), sensitivities = 83% (95% CI, 71%-91%) and 80% (95% CI, 67%-89%), and specificities = 98% (95% CI, 89%-99%) and 86% (95% CI, 72%-95%), respectively. In addition, these models showed an improved performance when compared with 3 other existing models (allP< 0.05).Conclusions:This initial report shows a clear benefit of including ovarian HistoScanning into mathematical models used for discriminating benign from malignant ovarian masses. These models may be specifically helpful to the less experienced examiner. Future research should assess performance of these models in prospective clinical trials in different populations.

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Fudholi, Ahmad, Muhammad Zohri, Ivan Taslim, Fitrotun Aliyah, and Arthur Gani Koto. "Heat transfer and efficiency of dual channel PVT air collector: a review." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 4 (December 1, 2019): 2037. http://dx.doi.org/10.11591/ijpeds.v10.i4.pp2037-2045.

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Solar energy is free, renewable and environment friendly and has been widely used in electricity generation and thermal energy through photovoltaic thermal (PVT) system. A PVT collector is a combination of a PV panel and a thermal collector in a single unit to simultaneously generate electricity and thermal energy. In this review, mathematical models for dual channel PVT air collectors is presented. This review presents various research and development, as well as heat transfer and thermal modelling of dual channel PVT air collectors. Moreover, various mathematical models that evaluate the performances base on energy and exergy analysis of dual channel PVT air collectors are presented. Energy balance is the basic concept in developing the mathematical models. Generally, steady-state one-dimensional linear first-order differential equations were reported for solution of mathematical model. Energy and exergy efficiencies of dual channel PVT air collectors were 22.5%–67% and 3.9%-58%, respectively.

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Karimov, Dastonback. "Reducing Air Flow Effect on High-Speed Train Current Collector with the Help of Aerodynamic Cowl." Proceedings of Petersburg Transport University 19, no. 4 (December 20, 2022): 793–99. http://dx.doi.org/10.20295/1815-588x-2022-4-793-799.

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Purpose: Investigation of aerodynamic effect on high-speed train pantograph using CFD-analysis method in FlowSimulation environment of SolidWorks software given uneven distribution of air high-speed mass flows in atop-car part of a rolling stock. Methods: Theoretical research was based on the application of the theory of constructive relations and continuum methods. Mathematical modeling was performed on a PC applying software products which use the means of computational fluid dynamics. Results: Refined digital model of a current collector has been developed which takes into account interaction nature in “current collector — contact wire” system under aerodynamic drag conditions. Practical significance: Device for the deflection of air masses when flowing around a current collector (a spoiler) is proposed that makes it possible to get rid of negative effects of: aerodynamic drag, filling-in construction pockets with snow masses and lever system icing consequences.

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Rodríguez, M. Marcela, Rodolfo H. Mascheroni, and Armando Quintero-Ramos. "Mathematical Modeling of Hot-Air Drying of Osmo-dehydrated Nectarines." International Journal of Food Engineering 11, no. 4 (August 1, 2015): 533–45. http://dx.doi.org/10.1515/ijfe-2014-0329.

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Abstract The influence of osmotic pretreatment on nectarines with solutions of glucose syrup and sorbitol and subsequent dehydration at different temperatures (60 °C, 70 °C, or 80 °C) was evaluated. The kinetics of moisture loss during drying was obtained and mathematical models were adjusted to estimate the kinetic parameters. Effective diffusion coefficients were calculated using Fick’s second law. All drying kinetics exhibited only a falling-rate period during hot-air drying owing to moisture loss in the osmotic pretreatment. Moisture loss was favoured by the use of sorbitol, whereas the diffusivity of water increased when glucose was used as an osmotic agent. Logarithmic and Midilli et al. models best described the changes in moisture over time, whereas Fick’s second law estimated water diffusion coefficient values between 4.96×10−9 and 2.43×10−8 m2 s−1. These models may be employed to predict the optimum conditions for osmo-dehydrating nectarines under hot-air drying at the industrial level.

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Matsumoto, Y., and M. J. Griffin. "Mathematical models for the apparent masses of standing subjects exposed to vertical whole-body vibration." Journal of Sound and Vibration 260, no. 3 (February 2003): 431–51. http://dx.doi.org/10.1016/s0022-460x(02)00941-0.

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Timmerman, Dirk. "The use of mathematical models to evaluate pelvic masses; can they beat an expert operator?" Best Practice & Research Clinical Obstetrics & Gynaecology 18, no. 1 (February 2004): 91–104. http://dx.doi.org/10.1016/j.bpobgyn.2003.09.009.

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Timmerman, D., A. C. Testa, T. Bourne, E. Ferrazzi, C. Van Holsbeke, and L. Valentin. "OC16.01: The pros and cons of using mathematical models to predict malignancy in ovarian masses." Ultrasound in Obstetrics and Gynecology 26, no. 4 (September 2005): 334–35. http://dx.doi.org/10.1002/uog.2088.

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Liu, Zhenjie, and Haitao Miao. "Update constraints on neutrino mass and mass hierarchy in light of dark energy models." International Journal of Modern Physics D 29, no. 13 (September 7, 2020): 2050088. http://dx.doi.org/10.1142/s0218271820500881.

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Combining cosmic microwave (CMB) background data from Planck satellite data, Baryon Acoustic Oscillations (BAO) measurements and Type Ia supernovae (SNe Ia) data, we obtain the bounds on total neutrino masses [Formula: see text] with the approximation of degenerate neutrino masses and for three dark energy models: the cosmological constant ([Formula: see text]CDM) model, a phenomenological emergent dark energy (PEDE) model and a model-independent quintessential parametrization (HBK). The bounds on the sum of neutrino masses [Formula: see text] depend on the dark energy (DE) models. In the HBK model, we confirm the conclusion from some previous work that the quintessence prior of DE tends to tighten the cosmological constraint on [Formula: see text]. On the other hand, the PEDE model leads to larger [Formula: see text] and a nonzero lower bound. Besides, we also explore the correlation between three different neutrino hierarchies and DE models.

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Dupuy, R., P. Laj, and K. Sellegri. "Cn to ccn relationships and cloud microphysical properties in different air masses at a free tropospheric site." Atmospheric Chemistry and Physics Discussions 6, no. 1 (February 1, 2006): 879–98. http://dx.doi.org/10.5194/acpd-6-879-2006.

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Abstract. The fraction of aerosol particles activated to droplets (CCN) is often derived from semi-empirical relationships that commonly tend to overestimate droplet number concentration leading to major uncertainties in global climate models. One of the difficulties in relating aerosol concentration to cloud microphysics and cloud albedo lies in the necessity of working at a constant liquid water path (LWP), which is very difficult to control. In this study we observed the relationships between aerosol number concentration (NCN), cloud droplet concentration (Nd) and effective radius (Reff), at the Puy de Dôme (France). A total of 20 cloud events were sampled representing a period of more than 250 h of cloud sampling. Samples are classified first according to air mass origins (Modified Marine, Continental and Polluted) and then according to their liquid water content (Thin, Medium and Thick clouds). The CCN fraction of aerosols appears to vary significantly according to the air mass origin. It is maximum for Continental air masses and minimum for Polluted air masses. Surprisingly, the CCN fraction of Modified Marine air masses fraction is lower than the continental air mass and from expected from previous studies. The limited number of activated particles in Modified Marine air masses is most likely the result of the presence of hydrophobic organic compounds. The limited activation effect leads to a 0.5 to 1 μm increase in Reff with respect to an ideal Marine case. This is significant and implies that the dReff/dNCN of low-continental clouds is higher than expected.

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Journal articles on the topic 'Air masses Mathematical models'

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