scholarly journals Research on the Characteristics of Turnout Flow Based on the Eccentricity Index of Maximum Flow Velocity

2021 ◽  
Author(s):  
W Xi ◽  
W G Lu

On the one hand, the characteristics of the turnout flow in the river are related to the stability of the turnout flow, and on the other hand, it is related to the safety of the flowing buildings near the bend turnout river. To observe the characteristics of the flow field in the chaotic river, the open channel surface layer digital particle image velocity (DPIV) system is used to measure the data in the physical model of the curved turnout river, and the maximum flow eccentricity (MFE) of the channel section is established. The flow pattern of the turnout flow is analyzed. The results show that the MFE index can effectively evaluate the flow pattern of the turnout flow. The MFE of the upper stream section of the curved river changes with the sudden change position of the flow between twice to 3.5 times the water surface width from the center point, and moves upstream with the increase of the flow rate, and moves downstream with the increase of the water level. This characteristic has guiding significance for the adjustment of the flow pattern of the front pool of the building.

2014 ◽  
Vol 07 (01) ◽  
pp. 1450008 ◽  
Author(s):  
J. B. SHUKLA ◽  
ASHISH GOYAL ◽  
P. K. TIWARI ◽  
A. K. MISRA

In this paper, a nonlinear mathematical model is proposed and analyzed to study the role of dissolved oxygen (DO)-dependent bacteria on biodegradation of one or two organic pollutant(s) in a water body. In the case of two organic pollutant(s), it is assumed that the one is fast degrading and the other is slow degrading and both are discharged into the water body from outside with constant rates. The density of bacteria is assumed to follow logistic model and its growth increases due to biodegradation of one or two organic pollutant(s) as well as with the increase in the concentration of DO. The model is analyzed using the stability theory of differential equations and by simulation. The model analysis shows that the concentration(s) of one or both organic pollutant(s) decrease(s) as the density of bacteria increases. It is noted that for very large density of bacteria, the organic pollutant(s) may be removed almost completely from the water body. It is found that simulation analysis confirms the analytical results. The results obtained in this paper are in line with the experimental observations published in literature.


2020 ◽  
pp. 1-36
Author(s):  
Antoine Le Riche

This paper analyzes the impact of trade on the stability properties of trading countries and on stationary welfare. We consider a two-country two-good two-factor overlapping generations model where countries differ in terms of their technology. In the autarky equilibrium and the free-trade equilibrium, indeterminacy relies, under dynamic efficiency, on a capital intensive consumption good and intermediate values of the elasticity of intertemporal substitution in consumption. Opening the borders to trade can be a source of a global destabilizing effect. Indeed, considering a free-trade equilibrium in which one country is an exporter of the consumption good and the other country is an exporter of the investment good, indeterminacy can occur with trade even though the two countries are determinate in autarky. Finally, opening to trade increases the stationary welfare of the country that exports the investment good and deteriorates the one of the other country.


1925 ◽  
Vol 8 (2) ◽  
pp. 183-188 ◽  
Author(s):  
P. A. Levene ◽  
M. H. Pfaltz
Keyword(s):  

1. The tripeptide glycyl-levo-alanyl-glycine in solution of either one or ten equivalents of alkali does not undergo racemization on standing. 2. The dipeptide levo-alanyl-glycine under the conditions given in (1) does not undergo racemization. 3. In ketopiperazines, levo-alanyl-glycine anhydride and in levo-prolyl-glycine anhydride under the influence of dilute alkalies, racemization takes place. 4. Racemization in the present experiments was never complete. The degree of racemization seems to depend, on the one hand, on the stability of the ketopiperazine ring; on the other, on the concentration of the alkali. 5. The significance of these observations will depend on the outcome of the work on a larger number of polypeptides and ketopiperazines. The work is now in progress in this laboratory.


1983 ◽  
Vol 48 (2) ◽  
pp. 364-378 ◽  
Author(s):  
Rolf Voigtländer ◽  
Jaromír Hlavatý ◽  
Jiří Volke ◽  
Viktor Bakos

The last two compounds in a 5-membered series of aromatic dinitro compounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0. In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo[b, e]-1,2-diazepine 5-oxide (IV) and 2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials. Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necessary by the low solubility of II in ethanol, proceeding in an anomalous way. In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of the one nitro group to an amino group while the other nitro group splits off as the anion NO-2 (this later giving an anodic wave). Its formation has been proved by standard addition in polarography and by a qualitative analytical test. The product which results through this electrode process and a follow-up chemical reaction is acridone. This in turn, reduces in the third, most negative 4-electron wave to dihydroacridine. The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH. The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X = O, S or CH2. Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products. The other group comprises the substances with X = CO and NH. Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups. The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X = CH2, O and S. A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X = CO has generally good preconditions for this mechanism.


The present paper contains some further developments of the theory of the moon, which are given at length, in order to save the trouble of the calculator, and to avoid the danger of mistake. The author remarks, that while it seems desirable, on the one hand, to introduce into the science of physical astronomy a greater degree of uniformity, by bringing to perfection a theory of the moon founded on the integration of the equations employed in the planetary theory, it is also no less important, on the other hand, to complete, in the latter, the method hitherto applied solely to the periodic inequalities. Hi­therto those terms in the disturbing function which give rise to the secular inequalities, have been detached, and the stability of the system has been inferred by means of the integration of certain equations, which are linear when the higher powers of the eccentri­cities are neglected and from considerations founded on the varia­tion of the elliptic constants. But the author thinks that the stability of the system may be inferred also from the expressions which result at once from the direct integration of the differential equations. The theory, he states, may be extended, without any analytical difficulty, to any power of the disturbing force, or of the eccentricities, ad­mitting the convergence of the series; nor does it seem to be limited by the circumstance of the planet’s moving in the same direction.


1860 ◽  
Vol 7 (35) ◽  
pp. 1-23 ◽  

The new position in which you have done me the honour this day to place me, entails upon me the duty of passing in review the varied interests and difficult problems of social and medical science, which are necessarily involved in promoting that which is the primary object of this Association, the welfare of the insane. The welfare of the insane! What a world of interests does not this small phrase include; what questions of individual happiness or misery; what questions of the prosperity or ruin of families; what questions of morality and law, of religion and politics; in fine, does it not ‘inferentially include the welfare of the human race. From time when Nebuchadnezzar ate grass, the happiness of the human race has often been at the mercy of the not metaphorical insanity of its rulers; and how often does not madness in lower stations imperil all that is precious. A mad orator on the floor of the house, or in the pulpit, may do comparatively little mischief, for opinion breaks no bones; but madness in a man of action, in an admiral for instance who commits suicide in the heat of an engagement, or an engineer in charge of a railway train; to what fearful disasters may it not give rise? In the world there is nothing great but man, in man there is nothing great but mind, says Hamilton. How vast, how wonderful a subject of study, therefore, is mind, whether in its integrity, or its decadence and ruin, in its health or its disease! Mental physicians, are we pledged to devote ourselves to the contemplation, and, as far as may be, to the full appreciation of this great subject, that we may oppose decay, and relieve disease ? Would it were possible to prevent it! Mental hygiene is, indeed, a subject vast as that of human progress. The highest and lowest stages of human development, those of the savage and the practical philosopher, are, perhaps, almost equally free from this direst scourge of human pride; the one with passions undeveloped, the other with passions under subjection. But the line of progress from one to the other of these termini, is strewn with those who have fallen in their weakness to linger and to die. Madness, the Nemesis of that ill-directed, ill-regulated development that we call civilization, what if it were to increase until the tendencies to mental disease overweighed in the community the conservative powers of health! There have been communities and times in which physical disease has threatened, or actually put an end to a race of men; and there have been communities and times in which folly and passion and delusion have been so widely endemic, that the fabric of society has been torn down, and even its very foundations shaken; and were it not for the resiliency of nature, the benign law of adjustment, by which deviations from law are a check upon further deviation, it is possible to conceive that the tendencies to mental infirmity and disease should increase; that passionate selfishness and insane folly should have continually augmenting power to reproduce themselves until acquired, and hereditary tendencies to madness should overbalance the forces of self-control and sanity, so that an observer, neither cynical nor metaphorical, might justly exclaim upon the “mad world,” and races, like families, become impotent for all except mischief and disaster, until time, the great physician, brought the only cure in extinction. Such speculations as these are not without their use, impossible as their realization may appear; they at least serve to make us value rightly the blessings we enjoy, blessings which from their commonness we are too apt to over look. We have no earthquakes in this country, and we calculate upon the stability of our buildings; we have no dead calms, and that world without motion, whose stagnant putridity has been painted by Byron and Coleridge, is to us a dread but impossible imagining. But the stability of our dwelling-place, and the restless agitation of the elements, although among those simple elementary conditions upon which our being depends, are also conditions which it is most easy to conceive might have been otherwise.


2015 ◽  
Vol 2 (1) ◽  
pp. 145-178
Author(s):  
J. Rombouts ◽  
M. Ghil

Abstract. We formulate and analyze a simple dynamical systems model for climate–vegetation interaction. The planet we consider consists of a large ocean and a land surface on which vegetation can grow. The temperature affects vegetation growth on land and the amount of sea ice on the ocean. Conversely, vegetation and sea ice change the albedo of the planet, which in turn changes its energy balance and hence the temperature evolution. Our highly idealized, conceptual model is governed by two nonlinear, coupled ordinary differential equations, one for global temperature, the other for vegetation cover. The model exhibits either bistability between a vegetated and a desert state or oscillatory behavior. The oscillations arise through a Hopf bifurcation off the vegetated state, when the death rate of vegetation is low enough. These oscillations are anharmonic and exhibit a sawtooth shape that is characteristic of relaxation oscillations, as well as suggestive of the sharp deglaciations of the Quaternary. Our model's behavior can be compared, on the one hand, with the bistability of even simpler, Daisyworld-style climate–vegetation models. On the other hand, it can be integrated into the hierarchy of models trying to simulate and explain oscillatory behavior in the climate system. Rigorous mathematical results are obtained that link the nature of the feedbacks with the nature and the stability of the solutions. The relevance of model results to climate variability on various time scales is discussed.


2018 ◽  
Vol 1 (4) ◽  
pp. 1005-1018
Author(s):  
Teuku Devansyah Putra ◽  
Eldina Fatimah ◽  
Azmeri Azmeri

Abstract: Pango Fly Over is located in the coordinate of 50 32' 07.32" LU (North Latitude) and 950 20' 52.90” BT (East Longitude) on Pango Village, Ulee Kareng Sub District, Banda Aceh. This bridge was built across Krueng Aceh River and the pillars were built in the river so that it narrows the river cross section and affecting the increasing of flow velocity. From the research location observation, it is found that the bridge pillars cause the more narrowing of the river cross section and there is the damage of the riverbank around the river bend located in the downstream of the pillars. If there is no further follow up, it will erode the national road. This research aims to find out flow pattern without and with the pillars, and to know the flow pattern behavior in the river bend. This research uses Surface Water Modeling System (SMS Version 11.2) Program. The length of the river reviewed is ± 500 meters. The flow discharge used in this research is the flood discharge which the period is Q – 100 and the value is 627.74 m³/second (passing the Pango Fly Over). From the result of the flow patter simulations, it is obtained that the maximum flow velocity without the pillars found in the middle location of V3 reviewed point on the distance 45 m from the riverbank is 0.45 m/sec and maximum flow velocity with the pillars found in the middle location of V3 reviewed point on the distance 33 m from the riverbank is 0.35/sec. In the outer bend of the flow pattern simulation result without pillars, it is obtained that the maximum velocity found in V6 reviewd location on the distance 50 m is 0.83 m/sec in the left side of the flow.Meanwhile in the downstream of the bend, the maximum velocity wit the bridge pillars found in V6 reviewd location on the distance 50 m is 0.95 m/det in the left side of the flow. In the bridge pillars downstream location, there is the river bend required the riverbank reinforcement and the riverbed reinforcement in order to avoid the erosion in the riverbank, because it will endanger the public facilities. Abstrak: Jembatan fly over Pango berada pada koordinat  50 32' 07.32" LU dan 950 20' 52.90” BT terletak di desa Pango Kecamatan Ulee Kareng kota Banda Aceh. Jembatan ini di bangun melintang Sungai Krueng Aceh dan pilar jembatan dibangun pada sungai sehingga terjadi penyempitan penampang sungai yang menyebabkan kecepatan aliran bertambah, Dari tinjauan lokasi penelitian pilar jembatan semakin mengalami penyempitan penampang sungai dan terjadi kerusakan tebing di sekitar belokan sungai yang berada di hilir jembatan. Bila tidak segera di tindak lanjuti akan berdampak tergerusnya jalan nasional. Penelitian ini bertujuan untuk mengetahui pola aliran tanpa adanya pilar dengan adanya pilar serta untuk mengetahui perilaku pola aliran yang terjadi pada belokan sungai. Penelitian ini menggunakan program Surfacewater Modeling System (SMS. Versi 11.2). Panjang sungai yang di tinjau ± 500 meter. Debit aliran yang digunakan pada penelitian ini mengunakan debit banjir periode ulang Q-100 tahunan yaitu 627,74 m³/detik (yang melewati jembatan fly over Pango). Dari hasil simulasi pola aliran didapatkan besaran kecepatan aliran tanpa pilar pada lokasi tengah aliran pada titik tinjauan V3 dengan jarak 45 m dari tanggul sungai kecepatan maksimumnya 0,45 m/det dan besaran kecepatan aliran dengan adanya pilar jembatan pada lokasi tengah pilar pada titik tinjauan V3 dengan jarak 33 m dari tanggul sungai kecepatan maksimumnya 0,35 m/det. Pada belokan luar dari hasil simulasi kecepatan aliran tanpa pilar besaran kecepatan maksimum pada titik tinjau V6 dengan jarak 50 m yaitu 0,83 m/det pada kiri aliran. Sedangkan di hilir belokan pada titik tinjau V6 dengan jarak 50 m dengan adanya pilar jembatan besaran kecepatan maksimum yaitu 0,95 m/det kiri aliran. Pada hilir pilar jembatan terdapat belokan sungai yang memerlukan perkuatan tebing dan perkuatan dasar agar tidak terjadi erosi di tebing sungai, sebab hal ini dapat membahayakan terhadap fasilitas umum.


Author(s):  
N. A. Ablyatipova ◽  
E. A. Ashurova

For the Russian reality, the stability and stability of the execution of transactions and obligations in the context of frequent and unpredictable changes in the external environment is becoming an increasingly important component of economic and legal relations. Modern civil legislation, on the one hand, guarantees the stability of existing legal relations, on the other, allows for the modification and termination of contracts both at the mutual desire of the parties, and in connection with the will of the other party, if it is granted such a right. The third option is a way to change or terminate the contract in court. However, at present, there are many subjective and objective circumstances that are not provided for by the parties when concluding the contract, which make it difficult or even impossible to continue performing obligations under it while maintaining the conditions that were originally laid down in it. Not always resolving of such situations envisaged by the legislator, but because there are situations when the parties relations are further complicated by the inability to quickly and effectively solve the current conflict, especially if parties are business entities and any delay can lead to significant financial costs not only of the parties of legal relations, but also third parties whose rights are directly or indirectly affected.


Author(s):  
Mary Elise Sarotte

This chapter addresses why November 1989 became the moment that the models for the future were launched. By the night of November 9, five developments had permanently altered the Cold War and produced a causal chain that resulted in the unintentional opening of the Berlin Wall. The nature of this causal chain suggests that theorists of power and theorists of ideas need to pay attention to each other to understand what happened. On the one hand, some developments were based on old-fashioned realist calculations. On the other hand, some developments were ones of attitude rather than capability, of ideas rather than material abilities. In the course of 1989, half of Europe had come to the conclusion that it need not continue to live under nondemocratic regimes in the interest of maintaining the stability of the whole.


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