Local Cosmic string in Lyra geometry     

F. Rahaman  S. Mal 《Astrophysics and Space Science》2006,302(1-4):3-5

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Kinetik der Methanfermentation des Klärschlammes     

Dr. Josef Malý 《Aquatic Sciences - Research Across Boundaries》1968,30(2):397-408

Zusammenfassung In der vorliegenden Arbeit wird die Fermentation der organischen Stoffe des Kl?rschlammes vom kinetischen Standpunkt untersucht. Für die Faulgasproduktion ist die T?tigkeit der Methanbakterien entscheidend. Bei der ?batch?-Fermentation des Kl?rschlammes mit Trockensubstanzgehalt von 5% wurde die maximale Wachstumsrate der Methanbakterien für die folgenden Inkubationstemperaturen bestimmt: für 20°C 0,02 Tage⁻¹, für 30°C 0,09 Tage⁻¹, für 50°C 0,17 Tage⁻. Im semikontinuierlichen Prozess wurde der spezifische Wirkungsgrad als Quotient der aus 1 Liter Faulraum produzierten Faulgasmenge (im ml) zum Inhalt der organischen Stoffe im Rohschlamm (in g/l) ausgedrückt. Die Abh?ngigkeit des spezifischen Wirkungsgrades von der Raumbelastung für Temperaturen von 20°C, 30°C und 50°C wurde graphisch dargestellt. Die Verdünnungsrate, bei der die maximalen Werte des spezifischen Wirkungsgrades erreicht wurden, sind für 20°C 0,12 Tage⁻¹, für 30°C 0,21 Tage⁻¹ und für 50°C 0,28 Tage⁻¹. Entsprechende Werte des spezifischen Wirkungsgrades waren der Reihe nach: 20 ml/g pro Tag, 63 ml/g pro Tag und 100 ml/g pro Tag. Die minimale Generatinsdauer der Methanbakterin betr?gt für 20°C 3,1 Tage, für 30°C und 50°C weniger als 2,5 Tage. Aus dem Vergleich des ein- und zwistufigem Betriebs geht hervor, dass bei einer l?nger als 10 Tage w?hrenden Aufenthaltsdauer der spezifische Wirkungsgrad der beiden Systeme identisch ist, bei kürzerer Aufenthaltsdauer leistet jedoch der einstufige Betrieb mehr.

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Summary The purpose of this study is to estimate the fermentation of the organic matter in sewage sludge from the point of view of kinetics. The activity of methane bacteria seems to be essential for the sludge gas production. In the batch fermentation of sludge containing about 5% of dry solids, the maximal growth rate for methane bacteria at given incubation temperatures was found to be: at 20°C 0,02 days⁻¹, at 30°C 0,09 days⁻¹, and at 50 °C 0,17 days⁻¹. For the semi-continous process, the specific efficiency of the fermentation system was expressed as the relation between the quantity (in ml) of sludge gas produced daily in a one liter digestion area and the volatile solids content in raw sludge (in g/l). The dependence of the specific efficiency upon the volume load at temperatures of 20°C, 30°C, and 50°C was determined graphically. The dilution rate for maximal values of the unit efficiency attained was at 20°C 0,12 days⁻¹, at 30°C 0,21 days⁻¹, and at 50°C 0,28 days⁻¹, corresponding maximal values of specific efficiency were 20 ml/g per day, 63 ml/g per day and 100 ml/g per day. Minimal generation time of methane bacteria is at 20°C 3,1 days, at 30°C and at 50°C less than 2,5 days. Comparison betwen single stage and two-stage operations, with detention periods of more than 10 days, shows that the specific efficiency is very much the same in both systems. However, at shorter detention periods and with the same digestion capacity, the single stage operation is more efficient.

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The dynamical evolution of stellar-planetary systems     

A. G. Mal’nev  V. V. Orlov  A. V. Petrova 《Astronomy Reports》2006,50(5):405-410

We have carried out numerical simulations of the dynamical evolution of young stellar-planetary groups using various means to choose the initial conditions, which reflect the various assumptions about the physics of planetary formation: that planets form in circumstellar disks or simultaneously with stars as a result of the fragmentation of molecular clouds. The main classes of stable stellar-planetary systems resulting from the dynamical evolution of groups are identified (the outer planets around binary stars and “star + planet” binary systems), and their main characteristics analyzed. The probabilities of the formation of various types of planetary systems are estimated. A preliminary analysis of the migration of planets under the action of perturbations from stars is performed in the framework of the adopted model. It is shown that this migration can occur both towards and away from the star.  相似文献   

Automatic Tree Identification and Diameter Estimation Using Single Scan Terrestrial Laser Scanner Data in Central Indian Forests     

R. Suraj Reddy  Chandra Shekhar Jha  Krishnan Sundara Rajan 《Journal of the Indian Society of Remote Sensing》2018,46(6):937-943

Forest inventory parameters, primarily tree diameter and height, are required for several management and planning activities. Currently, Terrestrial Laser Scanning (TLS) is a promising technology in automated measurements of tree parameters using dense 3D point clouds. In comparison with conventional manual field inventory methods, TLS systems would supplement field data with detailed and relatively higher degree of accurate measurements and increased measurement frequency. Although, multiple scans from TLS captures more area, they are resource and time consuming to ensure proper co-registration between the scans. On the other hand, Single scans provide a fast and recording of the data but are often affected by occlusions between the trees. The current study evaluates potential of single scan TLS data to (1) develop an automatic method for tree stem identification and diameter estimation (diameter at breast height—DBH) using random sample consensus (RANSAC) based circle fitting algorithm, (2) validate using field based measurements to derive accuracy estimates and (3) assess the influence of distance to scanner on detection and measurement accuracies. Tree detection and diameter measurements were validated for 5 circular plots of 20 m radius using single scans in dry deciduous forests of Betul, Madhya Pradesh. An overall tree detection accuracy of 85 and 70% was observed in the scanner range of 15 and 20 m respectively. The tree detection accuracies decreased with increased distance to the scanner due to the decrease in visible area. Also, estimated stem diameter using TLS was found to be in agreement with the field measured diameter (R² = 0.97). The RMSE of estimated DBH was found to be 3.5 cm (relative RMSE ~20%) over 202 trees detected over 5 plots. Results suggest that single scan approach suffices the cause of accuracy, reducing uncertainty and adds to increased sampling frequency in forest inventory and also implies that TLS has a seemingly high potential in forest management.  相似文献   

Dispersion of love waves in a spherical earth with corrugated surface     

A. K. Mal 《Pure and Applied Geophysics》1962,53(1):25-44

Summary Propagation of Love waves over the spherical surface of a layered earth model has been discussed with special emphasis on the dispersion produced in the layer. The velocity of the waves with large wave-length increases appreciably as compared to the case of plane layer. The analysis has been extended to deduce an expression for the dispersion equation of the waves when the upper layer is of varying thickness. The modifications imparted to the dispersion equation depends on the amplitude only and not the shape of the corrugations provided we neglect small quantities of the second order. The effect is a substantial decrease in the phase velocity and becomes more pronounced if the amplitude of the corrugations increases.  相似文献   

Indicative mean transit time estimation from δ<Superscript>18</Superscript>O values as groundwater vulnerability indicator in karst-fissure aquifers     

P. Malík  J. Švasta  J. Michalko  M. Gregor 《Environmental Earth Sciences》2016,75(12):988

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Evaluating Long-Term Evolution of Radionuclide Migration Conditions from a Repository at the Yenisei Site (Krasnoyarsk Krai)     

B. T. Kochkin  V. I. Mal’kovskii 《Water Resources》2017,44(7):931-939

The article considers the procedure aimed to identify and select the factors, events, and processes that can have an effect on the long-term safety of radioactive waste repository to be constructed at The Yenisei Site (Krasnoyarsk krai). The geological factors to be taken into account in the development of scenarios for safety assessment are determined. Tentative quantitative forecasts of radionuclide migration are made taking into account possible climate evolution and vertical rise of the territory. The sensitivity of radionuclide migration model to variations in these factors is assessed.  相似文献   

Automated construction of the boundaries of basin geosystems for the Volga Federal District     

O. P. Ermolaev  K. A. Mal’tsev  M. A. Ivanov 《Geography and Natural Resources》2014,35(3):222-228

Using the Volga (Privolzhskii) Federal District as an example, we offer the solution of such a currently central scientific and methodological problem as automated identification of the boundaries of basin geosystems under different landscape and geomorphological conditions in terms of multiresolution digital elevation models. The main stages of work are described, namely the development of the digital elevation model, its hydrological adjustment, identification of the boundaries of basin geosystems, and validity assessment of results obtained. The technique has been developed for constructing a hydrologically valid digital elevation model with the purpose of identifying the boundaries of basin geosystems.  相似文献   

Eddy covariance based methane flux in Sundarbans mangroves,India   总被引：1，自引：0，他引：1  

Chandra Shekhar Jha  Suraj Reddy Rodda  Kiran Chand Thumaty  A K Raha  V K Dadhwal 《Journal of Earth System Science》2014,123(5):1089-1096

We report the initial results of the methane flux measured using eddy covariance method during summer months from the world’s largest mangrove ecosystem, Sundarbans of India. Mangrove ecosystems are known sources for methane (CH₄) having very high global warming potential. In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans (India). The tower is equipped with eddy covariance flux tower instruments to continuously measure methane fluxes besides the mass and energy fluxes. This paper presents the preliminary results of methane flux variations during summer months (i.e., April and May 2012) in Sundarbans mangrove ecosystem. The mean concentrations of CH₄ emission over the study period was 1682 ± 956 ppb. The measured CH₄ fluxes computed from eddy covariance technique showed that the study area acts as a net source for CH₄ with daily mean flux of 150.22 ± 248.87 mg m^?2 day^?1. The methane emission as well as its flux showed very high variability diurnally. Though the environmental conditions controlling methane emission is not yet fully understood, an attempt has been made in the present study to analyse the relationships of methane efflux with tidal activity. This present study is part of Indian Space Research Organisation–Geosphere Biosphere Program (ISRO–GBP) initiative under ‘National Carbon Project’.  相似文献   

Evaluating factors responsible for contrasting signature of wasteland development in northern and southern Ganga Plains (Bihar State,India) with focus on waterlogging     

Suraj Kumar Singh  A. C. Pandey  V. S. Rathore  M. S. Nathawat 《Arabian Journal of Geosciences》2014,7(10):4175-4190

The present study provides assessment of wasteland development in Bihar State based on satellite data. Wasteland covers 6.90 % (6,501 km²) of the state area and exhibits dominance of waterlogged areas in North Bihar (25.28 %) and scrubland (26.61 %) in South Bihar. The waterlogged areas in the state are dominantly associated with northern Bihar plains (94 %) with minor development (6 %) in southern Bihar plains. Such unequal distribution of waterlogged land areas in northern and southern Bihar plains is largely governed by high cumulative discharge generated in the large catchment area in Himalayan mountain ranges in the upland areas of northern Bihar plains in contrast to low cumulative discharge generated within small catchments in the Chota Nagpur Plateau in the southern Bihar plains. It is evaluated that the relief and groundwater level define the primary controlling factors, whereas rainfall, watershed area, and upland/plain ratio exert secondary control. Lower relief areas with high rainfall exhibit high soil moisture thereby inducing conditions of waterlogging. The study signifies the potential of satellite image-based evaluation of waterlogging through the use of Digital Elevation Model, Tropical Rainfall Measuring Mission-based rainfall measurement, and temporal waterlogging assessment together with other terrain parameters for conceptual understanding of waterlogging in northern Bihar plains.  相似文献