Determination of nitrogenous gases evolved from soils in closed systems

The Analyst ◽  
1979 ◽  
Vol 104 (1239) ◽  
pp. 538 ◽  
Author(s):  
C. J. Smith ◽  
P. M. Chalk
Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 1021-1028 ◽  
Author(s):  
Eva Maria Wild ◽  
Maja Paunovic ◽  
Gernot Rabeder ◽  
Ilse Steffan ◽  
Peter Steier

Vindija cave in Croatia is famous for the Neanderthal bones found in layer G of its sediment profile. Radiocarbon dating has been performed mainly on this layer due to the great interest in its fossils. In addition to Neanderthal remains, the sediment in layer G contains bones from the cave bear. Cave bear bones are found also in other layers of the sediment profile and offer the possibility of studying the bears' evolutionary mode. Therefore, we tried to determine the time span covered by the entire profile. The U/Th age determination method was applied to cave bear bones from different layers of the profile. For the younger part of the profile, the U/Th ages were compared with the results of the 14C and the amino-acid racemization method. The agreement of the different methods indicates that closed-system behavior can be assumed for the fossil bones from Vindija cave. From this finding it may be deduced that bones from the lower sediment layers are also closed systems and that the U/Th ages of these layers are reliable. This conclusion is corroborated by the stratigraphy of the cave profile.


1995 ◽  
Vol 32 (9-10) ◽  
pp. 323-330
Author(s):  
M. Roš

For all water bodies especially for sea, lakes, and ground waters it is very important that nutrient pollution is the least possible (minimal). From municipal and industrial waste waters where considerable amount of nutrients is expected it is possible to remove nutrients with biological treatment. The first step is usually aerobic activated sludge treatment and the second step is combined anaerobic-anoxic-aerobic step in different combinations. A very effective process for nitrogen removal is anoxic activated sludge system. It is very important that in the first aerobic step complete nitrification is achieved. In our laboratory denitrification kinetics was studied. The objective of this study was determination of denitrification velocity and attendance of different parallel phenomena such as nitrite, disappearance of nitrate and nitrite, sulphide formation, etc. Denitrification process was studied in two systems, in closed system (such as in closed reactors for denitrification) and in open systems (such as in open denitrification tanks). We found out that denitrification rate in closed systems was from about 8 to 52 mg/l.h and was dependent on activated sludge type, sludge concentration, and temperature of the system. In open system (such as in an anoxic aeration tank) the rate of denitrification was lower than in closed system; it was from 4 to 15 mg/l.h dependent on activated sludge type, sludge concentration, and temperature of the system. Experiments were carried out in the range of temperature from 20° to 30°C.


2002 ◽  
Vol 3 (2) ◽  
pp. 83-94 ◽  
Author(s):  
David G. Renter ◽  
Jan M. Sargeant

AbstractEnterohemorrhagicEscherichia coli, particularly the O157(:H7) serogroup, has become a worldwide public health concern. Since cattle feces are often implicated as the source ofE. coliO157 in human infections, considerable resources have been devoted to defining the epidemiology and ecology ofE. coliO157 in cattle environments so that control might begin at the farm level. Diagnostic limitations and the complexity of often interrelated microbial, animal, herd, environmental and production factors have hindered the determination of the epidemiology, ecology and subsequent farm-level control ofE. coliO157. The widespread distribution ofE. coliO157, the transitory nature of fecal shedding, multiple potential environmental sources, lack of species specificity, and age-, feed- and time-related differences in cattle prevalence are documented. However, the significance and/or role of these factors in the epidemiology and ecology ofE. coliO157 is still unclear. Cattle are a major source ofE. coliO157, but it may be simplistic to believe that most herds are relatively closed systems with small percentages of cattle serving as true reservoirs. Practical on-farm control may require explicit definitions of the seemingly complex system(s) and the microbial, animal, herd, environmental and production factors involved in the multiplication, maintenance and transmission ofE. coliO157.


In a previous publication (Horn & Jackson 1972) there was defined a class of open reaction systems, called quasi-thermodynamic mass-action systems, whose statics and dynamics exhibit a regularity similar to that which can be found with closed systems. For instance, it was shown that in quasi-thermodynamic systems all equilibria are asymptotically stable and satisfy conditions of existence and uniqueness relative to certain subsets of the composition space. In this paper quasi-thermodynamic behaviour is related to the properties of a digraph (‘reaction diagram ’) and a set of vectors (‘complexes’) that may be associated with certain open reaction systems. The results presented allow the determination of the qualitative statics and dynamics of a large class of open reaction systems by simple computational procedures.


Author(s):  
Victor Romero-Rochin

We argue that a very large class of quantum pure states of isolated macroscopic bodies have sharply peaked energy distributions, with their width relative to the average scaling between $\sim N^{-1}$ and $\sim N^{-1/2}$, with $N \gg 1$, the number of atoms conforming the body. Those states are dense superpositions of energy eigenstates within arbitrary finite or infinite energy intervals that decay sufficiently fast. The sharpness of the energy distribution implies that closed systems in those states are {\it microcanonical} in the sense that only energy eigenstates very near to the mean energy contribute to their thermodynamic evolution. Since thermodynamics accurately describes processes of macroscopic bodies and requires that closed systems have constant energy, our claim is that these pure states are typical of macroscopic systems. The main assumption beneath the energy sharpness is that the isolated body can reach thermal equilibrium if left unaltered. We argue that such a self-sharpness of the energy in macroscopic bodies indicates that the First Law of Thermodynamics is statistical in character.


2021 ◽  
pp. 114-119
Author(s):  
А.С. Соболев ◽  
П.А. Ерофеев ◽  
А.А. Яшонков ◽  
А.Л. Фалько ◽  
И.Р. Епифанцев

Своевременность решений характеризуется соотношением динамических характеристик управляемого процесса и расходов времени на принятие решения. Для получения такого соотношения сначала обоснуем утверждение: время принятия решения системой с нелинейной решающей функцией равняется времени принятия решений системой с линейной решающей функцией, если соответствующие алгоритмы имеют одинаковую сложность. При изучении организационных объектов важно выделять класс целенаправленных или целеустремленных систем. В этом классе, в свою очередь, можно выделить системы, в которых цели задаются извне (обычно это имеет место в закрытых системах), и системы, в которых цели формируются внутри системы (что характерно для открытых, самоорганизующихся систем). Целеустремленные системы являются системами с явно выраженными целевыми устремлениями по достижения цели. Как правило это системы управления движущимися морскими объектами: судами и кораблями в условиях информационно-сложных ситуациях и деятельность таких систем нацелена на результат, а результат может быть достигнут если есть обратная связь. Цель исследований: проведение интроспективного анализа и синтеза целеустремленных систем в условиях информационно – сложной ситуации. Методы исследований – интроспективный анализ и синтез целеустремленных систем. При этом подходе возможно решение принципиальных проблем разработки информационной системы (ИС) методом выделения инвариантных блоков, реализация которых позволяет рассматривать структуру ИС как набор однотипных элементов и возможность построения управляемых объектов. Важной особенностью ИС является обеспечение возможности описания метода организации данных и алгоритмов оперирования данными в терминах используемого информационного языка. Целью данной работы является не перечисление или выбор возможных инвариантных блоков, (этот выбор зависит от характера решаемых задач системой и от свойств управляемых объектов), а построение такой модели блоков ИС и их описания на языке, понятном человеку и машине, которая позволяет создать набор алгоритмов и программ, обслуживающих систему, независящих от содержимого блоков конкретных ИС. Timeliness of decisions is characterized by the ratio of the dynamic characteristics of the controlled process and the time spent on making a decision. To obtain such a relation, we first substantiate the statement: the decision time by a system with a nonlinear decision function is equal to the decision time by a system with a linear decision function, if the corresponding algorithms have the same complexity. When studying organizational objects, it is important to distinguish a class of purposeful or purposeful systems. In this class, in turn, it is possible to distinguish systems in which goals are set from the outside (usually this is the case in closed systems), and systems in which goals are formed within the system (which is typical for open, self-organizing systems). Purposeful systems are systems with clearly expressed purposeful aspirations to achieve a goal. As a rule, these are control systems for moving marine objects: ships and ships in information-complex situations and the activity of such systems is aimed at the result, and the result can be achieved if there is feedback. difficult situation. Research methods - introspective analysis and synthesis of purposeful systems. With this approach, it is possible to solve the fundamental problems of developing an information system (IS) by the method of identifying invariant blocks, the implementation of which allows us to consider the IS structure as a set of elements of the same type and the possibility of constructing controlled objects. An important feature of the IS is the ability to describe the method of organizing data and algorithms for operating with data in terms of the information language used. The purpose of this work is not to enumerate or select possible invariant blocks (this choice depends on the nature of the tasks being solved by the system and on the properties of controlled objects), but to build such a model of IS blocks and their description in a language understandable to humans and machines, which allows creating a set of algorithms and programs serving the system that do not depend on the contents of specific IS blocks.


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