Jet ignition prediction in a zero-dimensional pre-chamber engine model

This paper presents a multi-chamber, multi-zone engine model to predict the ignition of a lean main chamber by a pre-chamber. The two chambers are connected by small cylindrical holes: the flame is ignited in the pre-chamber, hot gases propagate through the holes and ignite the main chamber through Turbulent Jet Ignition (TJI). The model original features are: (i) separate balance equations for the pre- and main chambers, (ii) a specific model for temperature and composition evolution in the holes and (iii) a DNS-based model to predict the ignition of the main chamber fresh gases by the burnt gases turbulent jets exiting the holes. Chemical reactions during TJI are the result of two competing mixing processes: (1) the hot jet gases mix with the fresh main chamber to produce heated zones and (2) at the same time, these hot gases cool down. (1) increases combustion and leads to ignition while (2) decreases it and can prevent ignition. The overall outcome (ignition or failure) is too complex to be modelled simply and the present model relies on recent DNSs of TJI which provided a method to predict the occurrence of ignition. Incorporating this DNS information into the engine model allows to predicts whether ignition will occur or not, an information which is not accessible otherwise using simple models. The resulting approach is tested on multiple cases to predict ignition limits for very lean cases, effects of H2 injection into the pre-chamber and optimum size for the holes connecting the two chambers as a function of equivalence ratio.

Genesis of the role of asset in different concepts of balance theories

Introduction. The history of accounting has always been directly dependent on the needs of users of such information. It was they who formed the queries for the financial statements that formed the basis of the management decision-making process. This historical process has contributed to the emergence of various balance theories. The assets of the company were recorded in the balance sheet for several stakeholder groups. It is the understanding of the dialectic of the formation of such requests that determines the process of displaying the assets of the enterprise. purpose. The purpose of the article is to study the genesis of balance theories and to determine the list of factors that influenced the understanding of the essence of the assets of the enterprise. A historical approach to research allows you to identify trends and predict the formation of approaches to balance in the future. Metods. To achieve this goal, scientific methods were used, both at the empirical and theoretical levels of research. The methods of analysis were used to compare the determination of the essence of static and dynamic balance theories in different scientific calculations. The historical method was used to understand the logic behind the development of these theories. Modeling and abstraction techniques have been used to address different situations related to the display of assets in different theoretical constructs of the balance sheet. Results. The article discusses the development of static and dynamic balance theory in the context of the doctrines of different scientists and gives a critical analysis of the trade- offs. The dominant influence of conflicting interests of different groups of users of accounting information on the formation of variants of dynamic and static balances is proved. For the first time, the peculiarities of reflecting assets in general and intangible in particular, within the legal and economic concepts of the theories under study are identified. The risks that compromise approaches to forming the domestic balance are identified and the ways of overcoming them are identified. Discussion. In order to increase the level of objectivity and materiality of the asset information presented in the financial statements, it is necessary to search for trade-offs between legal and economic concepts within separate balance theories. Studies have shown that attempts to synthesize the balance theories themselves and to bring them together into a single accounting document run into claims from users who have different interests. Consideration of issues regarding the priority of forming a balance sheet for the benefit of stakeholders allows to state the necessity of reporting on a specific purpose: solvency, investment attractiveness, etc.

METHODS OF BALANCE SHEET ITEMS EVALUATION AND RECOGNITION IN FINANCIAL ACCOUNTING AND THEIR IMPACT ON LIQUIDITY INDICATORS

Displaying and evaluation methods of the accounting information in the financial reports influence greatly the authenticity, indicator evaluation and making decisions of the economic nature. In the article the evaluation methods of separate balance items, their influence on the indicators of the companies’ liquidity are interpreted, the problems of the balance item classification in the financial reports are updated. The authors believe that when investigating a specific financial indicator (for example, liquidity) it is important to analyse and evaluate both the methodology of data acquisition in accounting and to evaluate the methods of recognition of these elements in financial reports.

The relationship between serum urea levels and dietary nitrogen utilization in young men

1. Results from metabolic balance studies in young adult men were examined for the relationships between the concentration of serum urea (SUN) and the efficiency of dietary nitrogen utilization. A total of 231 separate balance periods were included in the analysis. Net protein utilization (NPU) was used as an index of dietary protein quality.2. Protein intake ranged from 0·27–0·73 g/kg body-weight per d in the various experiments. There was a highly significant negative correlation between NPU and urea levels. The relationship was: NPU = 1·23–0·029 × SUN (mmol/l) (r = −0·89).3. These results are considered in relation to the evaluation of protein quality in adult humans.