scholarly journals II.—The Fundamental Problems of Petrogenesis, or the Origin of the Igneous Rocks

1911 ◽  
Vol 8 (6) ◽  
pp. 248-257 ◽  
Author(s):  
Franz Lœwinson-Lessing

The question of the origin of igneous rocks, their diversity and genetic relationships, represents that fundamental problem of petrography which has been for many years the object of inquiry for petrologists as well as for geologists and chemists. Whilst the amount and scope of detailed observation were growing, the methods of experimental investigation improved, and as the eruptive rocks came to be studied from the point of view of physical chemistry, so the petrogenetical horizon became larger and wider. Thus, on the basis of numerous minute and detailed observations were built broad generalizations that gave rise to new problems.

1920 ◽  
Vol 57 (7) ◽  
pp. 290-299
Author(s):  
R. H. Rastall

AT the present time most mining geologists appear to be in general agreement on the principle that primary ore-deposits are derived from igneous magmas. Furthermore, it is now almost universally recognized that the segregation and concentration of the metals and their compounds into payable ore-deposits is but part of a larger and more fundamental problem, namely, the differentiation of the igneous rocks, a problem which has exercised the ingenuity of petrologists for many years past and is still by no means solved. Unfortunately most of the speculations and theories put forward in explanation of these phenomena are in the main founded on facts and inferences derived from the study of the silicates; comparatively few petrologists have taken into account the behaviour of the oxidic and sulphidic compounds of the useful metals, which are commonly regarded in the light of rare and accidental constituents of the magma, rather than as having any particular bearing on the point at issue. The most notable exception to this general statement is Vogt, whose work on slags and ore-deposits is of an epoch-making character from the theoretical point of view, as well as of immense practical importance in smelting and blast-furnace practice. However, within the last few years great attention has been devoted by mining geologists to the subject of the genesis of ore-deposits, mainly because of its bearing on the question of persistence in depth or the replacement at lower levels of one ore by another, such as is known to occur in certain cases. It may be suggested, therefore, that the time has now come when it may be possible to attempt to combine the facts hitherto discovered along different lines of research into a coherent whole.


1886 ◽  
Vol 3 (11) ◽  
pp. 481-489 ◽  
Author(s):  
J. J. H. Teall

If we take a general view of the present position of geological science, we are struck by the fact that, although there is substantial agreement amongst geologists on matters relating to the origin of the rocks usually designated as aqueous and igneous, the greatest diversity of opinion prevails with regard to the circumstances under which the so-called metamorphic rocks have been produced. Every fragment of evidence calculated to throw light on the origin of these rocks, therefore, deserves the most careful consideration. Of recent years special attention has been directed to the effects of mechanical energy in modifying the mineralogical and structural characters of rocks originally formed by aqueous and igneous agencies; and a suspicion has been aroused that it is in this direction that we must look for a solution of many of the problems connected with the origin of the crystalline schists. A visit to the Lizard Peninsula of Cornwall during the present summer has convinced me of the immense importance of this view so far as that district is concerned. That portion of the peninsula which lies south of a line drawn from Porthalla on the east to Polurrian Cove on the west is formed.partly of igneous rocks—such as gabbro, greenstone, serpentine, and granite—and partly of crystalline schists. The igneous rocks, in certain places, become foliated and sohistose and sometimes show a definite banding due to a variation in the relative proportions of the different constituents. In other words they present characters which are usually regarded as distinctive of the crystalline schists. There is, moreover, evidence to show that these characters are mainly the result of a yielding to earth-pressure subsequent to the consolidation of the original rock. At the present moment, having just returned from the district, I am unable to treat the subject from a general point of view with any prospect of success; but it has occurred to me that some details with regard to one of the rocks may not be without interest to members of the Association.


2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Niklas Neupert ◽  
Birger Ober ◽  
Franz Joos

In recent years, overspray fogging has become a powerful means for power augmentation of industrial gas turbines (GT). Most of the studies concerning this topic focus on the problem from a thermodynamic point of view. Only a few studies, however, were undertaken to investigate the droplet behavior in the flow channel of a compressor. In this paper, results of experimental investigation of a water laden flow through a transonic compressor cascade are presented. A finely dispersed spray was used in the measurements (D10 < 10 μm). Results of the droplet behavior are shown in terms of shadowgraphy images and images of the blade surface film pattern. The angle of attack, the incoming velocity, and the water load were varied. The qualitative observations are related to laser Doppler and phase Doppler anemometer (LDA/PDA) data taken in the flow channel and at the outlet of the cascade. The data represent a base for numerical and mean line models of two-phase compressor flow.


2021 ◽  
Vol 298 (5 Part 1) ◽  
pp. 57-62
Author(s):  
Illia Morhachov ◽  

The relevance and urgent need for the formation of complementary pension provision for the population in Ukraine has been determined. The complementary pension provision of the citizens of the country is considered as not at all implying the complete destruction of the existing solidarity pension system, but only the formation of additional mechanisms that make the pension provision of citizens generally successful even in the existing conditions. Such a mechanism can be a set of investment funds (joint investment institutions) in the country, which will add to the existing solidarity pension system elements of capital accumulation through the activation of investment processes. The purpose of the work was to determine the fundamental problems and prospects of Ukrainian investment funds (joint investment institutions) from the point of view of complementary pension provision for citizens in Ukraine. The purpose of the work was to determine the fundamental problems and prospects of Ukrainian investment funds (joint investment institutions) from the point of view of complementary pension provision for citizens in Ukraine. The article defines that the prerequisite for effective complementary provision is the optimal balance structure, which is similar to such better analogues as the Berkshire Hathaway and the Vanguard S & P 500 ETF. It is specified that the formation of a balance sheet structure in accordance with the best foreign analogues contradicts the current regulatory framework in the country, which is a fundamental problem in the formation of complementary pension provision on the basis of joint investment institutions. It is determined that the majority of investment funds existing in Ukraine in the form of joint investment institutions (ISI) under the current legislation are not able to provide a complementary pension for citizens of the country at a sufficient level of efficiency due to the impossibility of forming an optimal asset structure. The fundamental problem of ISI in the country is the legislative restrictions on the formation of the optimal structure of their balance. The optimal balance sheet structure of the investment fund, in particular assets (dominated by shares of the world’s leading companies) and liabilities (dominated by equity and raised funds by issuing bonds) is the basis for the effectiveness of complementary pension provision.


2020 ◽  
Vol Vol. 36 (No. 2) ◽  
pp. 71-77
Author(s):  
Katarina Haviernikova ◽  
Janka Betakova

Small and medium-sized enterprises (SMEs) in developed countries represent an important part of their economic environment. They belong to accelerators of economic development in regions and countries. One of the specifications of SMEs is that they allow people to learn to use their own entrepreneurial skills. Thus, the success of SMEs depends on the skills of the person who is responsible for business management in the enterprise. Without skilled and competent managers no activity will be performed effectively. The development and changes in the economic environment, in which SMEs operate, cause the various reversals connected with uncertainty and the resulting risks. A competent person (owner/manager) in SME will need to anticipate these risks and develop appropriate mitigation and strategies for them. The owner/manager of SME should consider the fact, that there could be deviations in the realization process against the planned goal. This deviation presents the risk and the representative of SME should know, how it is possible to manage this risk. It means to reduce its negative impact. The lack of knowledge is a fundamental problem in the failure of most initiatives in the SMEs and the lack of experience can become a major risk to business survival. The goal of owners/managers in SMEs should be to reduce the possible errors and risks in that way that the SME gets into a situation in which it can anticipate changes, and it is able to respond to them and exploit them to their advantage. Each SME is unique and the risk may occur differently in comparison with other SMEs. Risk management and mitigation of risk are important to ensure the security of the company and its continuous development. The risk management in SMEs is perceived as a means of the improvement of SMEs’ success in their activities, due to the fact, that in most cases the unpredictable situations represent a serious loss-making exposure for the SMEs business sector which leads to the loss. For those SMEs whose capital base is insufficient, they can have catastrophic consequences in the case of realized activities, and they can lead to financial losses and subsequently to possible bankruptcy. For this reason, risk management is a prerequisite for minimization of the negative effects of unexpected situations. Still, a lot of SMEs rarely carry out process-related activities risk management. It is affected by limited resources (financial, human), which SMEs have, and which process risk management. There is a wide range of studies focused on risk management in SMEs, but only several of them are focused currently on the responsibility for risk management. This paper contributes to the dissemination of knowledge about the responsibility for risk management in SMEs and provides wider analysis in ways of responsibility for it. To reach the main of the paper, questionnaire surveys among 1018 Slovak SMEs were conducted. We compared the responsibility for risk management in SMEs between two groups of SMEs – technological and tourism from the point of view of sized category, and regional of SMEs. For the evaluation of differences and dependencies among three groups of respondents’ answers, according to their size category, economic branch in which they operate, and regional location, the Chi-square test was used. The associations among respondents’ answers were evaluated through Cramer’s V. The results showed the differences in responsibility for risk management among Slovak SMEs. The results of this study may provide implications for subsequent research focused on responsibility for risk management in the wider context.


1953 ◽  
Vol S6-III (1-3) ◽  
pp. 153-173 ◽  
Author(s):  
Pierre Lapadu-Hargues

Abstract In a majority of cases, amphibolites derived from sedimentary rocks can be distinguished from those derived from dioritic or gabbroic igneous rocks on the basis of average chemical composition. From the purely chemical point of view, it is possible to consider that eclogites result from metamorphism of certain types of heteromorphic gabbros such as the ariegites,and ultimately give rise to amphibolitic rocks. Chemical analyses are included.


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