Modelling of radar backscattering from low-salinity ice with ice ridges

Abstract

Radar backscattering from a snow-free ice surface characterized by an exponential correlation function is studied for conditions typical in the Baltic Sea. The C-band backscattering coefficient from first-year ice is normally found to be characterized primarily by the air-ice surface roughness. However, if the salinity and temperature are low, as in the Baltic Sea, both volume scattering and ice-water surface scattering might contribute. Even more important than scattering from the level ice is scattering from the ice ridges, and a simple approach is taken to characterize the properties of ice ridges and the corresponding scattering.     

PRINCIPLES OF ECONOMIC GROWTH

The economic system is viewed as a complex system of actors that interact by competition and coalition. Its evolution is described by morphodynamics, a general theory based on the thermodynamics of physical systems. The economic system then is represented as exchanging services and monetary signs with its environment, namely people. These exchanges are ruled by principles analogous to the principles of thermodynamics. Thus, reversible exchanges found a theory of money supply, wages and prices, whereas irreversible exchanges account for monetary profits, inflation and the long term growth of the economy.     

An evaluation of ultralight aircraft capability for remote sensing applications in West Africa

Abstract

An ultralight aircraft was used to make concurrent, near continuous measurements and to acquire spectral responses in several wavelengths over various ground features: water bodies (river and irrigation channels), geomorphological features (sand banks, levees, iron crust), aquatic vegetation (rice and spontaneous aquatic vegetation) and stubbles (millet and sorghum). The experiment was performed in Mali, along the Niger river. The airborne instrumentation made it possible to collect simultaneously spectral responses in the MSS and SPOT bands, flying height by laser rangefinder and colour video tapes of the area over-flown. Five profiles, several kilometres long, were obtained at heights above the ground varying from 20 to 75 m. Along each profile spectral data and flying height were scanned every 0-1 s and recorded on the audio channel of a videotape, after multiplexing and analogue-to-digital conversion. The preliminary data analysis suggest a very high potential for ultralight aircraft in remote sensing applications.     

Biomass and Patulin Production by Byssochlamys nivea in Apple Juice as Affected by Sorbate, Benzoate, SO2 and Temperature

The effects of potassium sorbate, sodium benzoate, SO₂ and incubation temperature on biomass and patulin production by Byssochlamys nivea in apple juice were determined. Growth at 21, 30 and 37°C over a 25-day incubation period was significantly retarded by 75 ppm SO₂, 150 ppm potassium sorbate and 500 ppm sodium benzoate. Biomass accumulated to approximately 500 mg/100 ml in control samples of apple juice. Patulin was produced in the highest concentrations at 21°C after 20 days incubation. After reaching a maximum concentration at 30 and 37°C, a rapid decline in patulin content was observed. Patulin production was also observed at 12°C. On the basis of concentration, SO₂ had the most significant effect on the rate of biomass and patulin production by B. nivea followed by potassium sorbate and sodium benzoate, respectively.     

Evaluation of morphological representative sample sizes for nanolayered polymer blends

The size of representative microstructural samples obtained from atomic force microscopy is addressed in this paper. The case of an archetypal one‐dimensional nanolayered polymer blend is considered. Image analysis is performed on micrographs obtained through atomic force microscopy, yielding statistical data concerning morphological properties of the material. The variability in terms of microstructural morphology is due to the thermomechanical processing route. The statistical data is used in order to estimate sample size representativity, based on an asymptotic relationship relating the inherent point variance of the indicator function of one material phase to the statistical, size‐dependent, ensemble variance of the same function. From the study of nanolayered material systems, the statistical approach was found to be an effective mean for discriminating and characterizing multiple scales of heterogeneity.     

EXTENDING THE CONCEPT OF INTERVAL

The relative variation in length found among the intervals between occurrences of characters in written text provides extremely valuable clues as to the identity of those characters. It is possible to obtain still more identity information by extending the definition of ‘interval’ so that intervals of various kinds can be distinguished. In addition, it is possible to make use of ‘complex’ or ‘multi-dimensional’ intervals by giving simultaneous consideration to a number of adjacent ‘simple’ intervals.     

On the foundation for variable radix computing systems

Most modern computers with very few exceptions operate on the binary number system, This paper suggests a new generation of computer systems capable of performing computations in many number systems. At the present, a modern computer handles numbers other than binary through encoding prior to performing the arithmetic operations. The converting processes of encoding and decoding are both wasteful and time consuming. The proposed system is able to carry out computations in a given radix without conversions. In order to operate on a specific number system a radix control can be preset to the desired value, the computer is then converted instantly to be of that radix. In general, a number system is formed basically from counting with proper carry or carries to be generated when a desired radix is reached. High speed pulse counting with a controllable and variable carry producing mechanism is thus the most direct and efficient approach for the implementation of a variable radix computer system. In essence, a high speed electronic variable radix computer is a counterpart of a mechanical calculator which would consist of essentially wheels with number of teeth variable. This paper attempts to lay the basic and the most essential foundation necessary for such a versatile system. Similar to the conventional systems, the addition of numhers in an arbitrary radix can be performed by the use of a variable radix adder ; and the subtraction by the addition of the (R -l)'s complement, where R is the radix. Multiplication can be carried out by repeated additions and the division by the cyclic subtractions. The chosen number representation will be presented in the paper first and then the formuli, which are given either in simple expressions or in the compact series forms, for the basic arithmetic operations. In addition, numerical examples in various radices are given for the readers to ponder and enjoy.     

A universal building block for all pulse computing systems

Proposed in this paper is a universal building block for the implementation of all computing systems including various types of calculators, high speed largo size computers and generalized computing systems (Yii 1974). The word ‘ universal ’implies that the unique basic building blocks can be shared by both the arithmetic unit and the memory for a given system and utilized as the basic building blocks for the implementation of any conceivable computing system. It is essentially an electronic counterpart of a hypothetical mechanical gear with the number of teeth variable. From the circuit point of view, it is conceivable of being either a variable pulse train generator or a variable scalar with memory. The use of the magnetic core as a memory core is no longer restricted to be a bistable element. It is enabled to memorize a digit of an arbitrary radix by introducing a brand new circuit technique of partial switchings with alterable current biases. The interconnections between the basic blocks can be made either directly or by way of the conventional binary logic elements. Consequently, any existing computing systems, however complex, can be duplicated with the additional feature of being able to vary the radix.     

Effect of temperature and time on solvothermal synthesis of tetragonal BaTiO<Subscript>3</Subscript>

Tetragonal BaTiO₃ nanoparticles are synthesized via solvothermal route in an ethanol water mixture. Ba(OH)₂·8H₂O is used as Ba precursor and TiO₂ (P25 Degussa ∼25 nm, 30% anatase, 70% rutile) is used as Ti precursor in the Ba : Ti molar ratio 2 : 1. Effect of temperature and time study on solvothermal synthesis of BaTiO₃ revealed that a moderate reaction temperature i.e. 185°C and longer reaction time favour tetragonal phase stabilization. Dissolution–precipitation appears to be the transformation mechanism for the crystallization of BaTiO₃ from particulate TiO₂ precursor.