scholarly journals Seismic analysis of the zaouiat ait mellal twin tunnels of Agadir motorway (Morocco)

2020 ◽  
Vol 150 ◽  
pp. 03001
Author(s):  
Abdelhay El Omari ◽  
Mimoun Chourak ◽  
Carlos Navvaro Ugena ◽  
Seif-Eddine Cherif ◽  
Mohamed Rougui ◽  
...  
Keyword(s):  
Seismic Analysis ◽  
Free Field ◽  
Bending Moment ◽  
Structural Elements ◽  
Underground Structures ◽  
Maximum Displacement ◽  
The Difference ◽  
The Stability ◽  
The One ◽  
Twin Tunnels

Underground structures, such as tunnels, are vital for ensuring all kinds of transportation; and being buried under the surface makes them exposed to soil dynamics. Added to the moderate seismic activity in Morocco, the stability of tunnels is put to the test. This paper examines the interaction between the ZAM (Zaouit Ait Mellal) twin tunnels between the cities of Marrakesh and Agadir, using the Difference Element Method provided by FLAC 2D software. The acceleration is introduced as the one related to the historic event of El centro 1940 with free-field boundary conditions in the numerical model, with three configurations: tunnel 1 without tunnel 2, tunnel 2 without tunnel 1 and tunnel 1 with tunnel 2. The results of the simulations indicate that the differences values of the maximum displacement, axial force and bending moment on structural elements are very noteworthy from the configuration of the tunnel (single) to the twin tunnels in order to prove the interaction between these latter under seismic loading.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

New Boundaries, New Relationships

2020 ◽  
pp. 79-97
Author(s):  
LaTonya J. Trotter
Keyword(s):  
Registered Nurses ◽  
Nurse Practitioner ◽  
Power Relations ◽  
Medical Work ◽  
Nurses And Physicians ◽  
Signal Changes ◽  
The Difference ◽  
The Stability ◽  
The One ◽  
The Relationship

This chapter evaluates how the presence of the nurse practitioner (NP) does not just signal changes in nursing work; it portends changes in medical work. Although real tensions exist between nurses and physicians, broadly speaking, they have worked collegially alongside one another for well over a century. This collegiality has endured despite significant changes in what both physicians and nurses do for patients. Its endurance, however, has been predicated on the one thing that has not changed: the power relations between the two. It is the difference in authority, and not just the difference in work, that undergirds the stability of the relationship between the two professions. The NP threatens to disrupt that stability. When registered nurses (RNs) become NPs, they are not just learning new skills; they are crossing lines of authority that they had previously learned to treat as constitutive of their profession. The chapter then looks at the voices and experiences of the NPs of Forest Grove Elder Services. Their narrated and actual practices negotiated physician authority in very different ways.

scholarly journals Parametric Study of Pile Response to Side-by-Side Twin Tunneling in Stiff Clay

2020 ◽  
Vol 10 (2) ◽  
pp. 5361-5366
Author(s):  
N. Mangi ◽  
D. K. Bangwar ◽  
H. Karira ◽  
S. Kalhoro ◽  
G. R. Siddiqui
Keyword(s):  
Parametric Study ◽  
Three Dimensional ◽  
Bending Moment ◽  
Small Strain ◽  
Percentage Difference ◽  
Stiff Clay ◽  
The One ◽  
Numerical Parametric Study ◽  
Pile Response ◽  
Twin Tunnels

A three dimensional coupled-consolidation numerical parametric study was carried out in order to gain new insight of single pile response to side-by-side twin tunneling in saturated stiff clay. An advanced hypo plasticity (clay) constitutive model with small-strain stiffness was adopted. The effects of relative to the pile tunnel depths were investigated by simulating the twin tunnels near the pile at various depths of tunnels, namely near the pile shaft, adjacent to the pile toe, and below the pile toe. It was found that the second tunneling in each case resulted in a larger settlement than the one due to the first tunneling with a maximum percentage difference of 175% in the case of twin tunneling near the mid-depth of the shaft. This occurred due to the degradation of clay stiffness around the pile during the first tunneling. Conversely, the first tunneling-induced bending moment was reduced substantially during the second tunneling. The most critical location of twin tunnels relative to the pile was found to be below the pile toe.

scholarly journals The Potential Of Steel Wire As A Binder With Plates To Withstand Loads

Teknik ◽  
2020 ◽  
Vol 41 (3) ◽  
pp. 219-224
Author(s):  
Deardo Samuel Saragih ◽  
Novdin Manoktong Sianturi ◽  
Virgo Erlando Purba ◽  
Dermina Roni Santika Damanik
Keyword(s):  
Steel Wire ◽  
Structural Elements ◽  
Test Medium ◽  
Steel Wires ◽  
Connection System ◽  
Time Stage ◽  
The Difference ◽  
The Stability ◽  
Settlement Analysis ◽  
Strong System

Road and bridge construction needs to be supported by a strong system, both in terms of material and connections between structural elements. A pile reinforcement connection system with slab support construction on it needs to be considered to work together in carrying the load. Therefore, research is needed to determine how much effect the steel wire has as a binding pile with a plate in resisting uniform loads on it. This research was conducted by testing the model in a laboratory on a test medium that was reinforced with the pile with the slab system. Pile joints are distinguished bound perfectly and unbound. A reduction settlement analysis is performed on the difference in settlement for bound and unbound piles. The results showed that the pile system's performance, which was bound with steel wires on the slab, was better at resisting loads. This is known from the reduction of settlement for bound and unbound piles, which is 11.43% for the time stage and 11.51% for the load stage. The system can work together so that the stability of construction is better maintained and more durable.

scholarly journals Dynamic seismic analysis of bridge using response spectrum and time history method

2021 ◽  
Author(s):  
Marame Brinissat ◽  
Rajmund Kuti ◽  
Zouhir Louhibi
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Bending Moment ◽  
Highway Bridge ◽  
Structural Elements ◽  
Base Shear ◽  
Shear Forces ◽  
Nonlinear Analyses ◽  
Ground Motion Records

Dynamic analysis is very important to better understand the performance of structural elements of a bridge. For this purpose, a seismic analysis of an Algerian highway bridge designed with the new Algerian seismic bridge regulation (RPOA -2008) was carried out using linear and nonlinear analyses. Therefore, response spectrum, time history analyses were performed to evaluate the seismic responses of the designed bridge. The performance of the designed bridge is assessed using 10 ground motion records. The proposed methodology allows an efficient comparison of the seismic response of the bridge in terms of base shear forces, bending moment and displacements. Finally, the paper concludes with a discussion of the specific outcomes.

scholarly journals Assessment of the stability of bat ectoparasite communities using a Principal Component Analysis (PCA) method

2019 ◽  
Vol 8 (1) ◽  
pp. 119-124
Author(s):  
Galina Anatolievna Fadeeva ◽  
Elena Evgenievna Boryakova
Keyword(s):  
Principal Component Analysis ◽  
Principal Component ◽  
Component Analysis ◽  
Parasite Communities ◽  
Parasitic System ◽  
Pca Method ◽  
The Difference ◽  
The Stability ◽  
The One

The paper deals with a research of epiparasite communities in native karst caves in the South of Nizhny Novgorod Region. Six species of bats such as Daubentons water bat, Brandts bat, whiskered bat, pond bat, northern bat and long-eared bat were examined. A Principal Component Analysis was used to identify factors influencing the composition of ectoparasites as well as the number and distribution of mites in mixed colonies of bats. As the cave and its inhabitants can be considered as a microbiotope, it is obvious that there are specific relations between inhabitants in caves. Special habitat conditions indirectly influence the parasitic systems developing there which are characterized by certain stability. Mann-Whitney U-test was used to estimate the difference between samples of animals from different habitats. Methods of nonparametric statistics didnt find significant distinctions by the hosts, years and biotopes, the bat colony and their ectoparasites can be estimated as a single complexly organized system, existing long in space and time. From all possible factorial space four factors have significant effect on systems. The contribution of the first and second factors is equal to 65% of variance (specificity of parasites to hosts and a factor of dominant species presence). In parasite communities of bats interrelations which cause successful existence of all types without the expressed competition are observed. Our results indicate a complex relationship between the parasites in the community on the one hand, and long-term existence of the community on the other hand. Each member of parasitic system has a position in factorial space. In parasite communities of bats we met only one factor-dependent species ( Spinturnix acuminatus, Sp. plecotinus, Leptotrombidium russicum ). Species that show moderate and positive, moderate and negative correlation dependence with several factors are found. For example, Spinturnix myoti , Sp. kolenatii , Macronyssus heteromorphus , etc. Heterogeneity of environmental impact on the parasitic systems which are formed in natural caves provides stability of bat parasite communities in general.

scholarly journals Model Test and Theoretical Analysis of New and Old Embankments Differential Settlement Considering Lateral Deformation

2021 ◽  
Author(s):  
Gao-hang Lv ◽  
Wei Cui ◽  
Shu Jian Wang
Keyword(s):  
Model Test ◽  
Calculation Method ◽  
Lateral Deformation ◽  
Low Degree ◽  
Deformation Law ◽  
Degree Of Consolidation ◽  
The Difference ◽  
The Stability ◽  
The One ◽  
Deformation Coefficient

Abstract In the embankment widening project, the new embankment will produce large deformation due to the low degree of consolidation, which will affect the stability of the embankment. Obtaining the settlement law of embankment is the premise to ensure the stability of the embankment. In this paper, the deformation law of the new embankment is studied through the embankment model test, and the settlement calculation method of the new embankment is proposed. The model test results show that the new and old embankments have a large settlement difference during the loading process, and the maximum settlement of the new embankment is twice that of the old embankment. The lateral deformation of the new embankment is directly proportional to the vertical deformation, sliding occurs under the ultimate load, and the bearing capacity is lost. Based on the one-dimensional calculation method, the lateral deformation coefficient is introduced, and the two-dimensional embankment settlement formula is obtained. The new embankment is meshed, and the deformation of each node is calculated by the formula, and the difference between the settlement and the model test data is 6.2%, which proves the feasibility and accuracy of the calculation method.

Determining The Minimum Distance Between Centers of Two Parallel Tunnels to Apply The Law of Super Position in Order to Calculate Subsidence by Using The Software FLAC 3D

2015 ◽  
Vol 1 (1) ◽  
pp. 13-20
Author(s):  
Hamid Reza Samadi ◽  
Mohammad Reza Samadi
Keyword(s):  
Minimum Distance ◽  
Surface Subsidence ◽  
Urban Traffic ◽  
Underground Structures ◽  
Rapid Population Growth ◽  
The North ◽  
Flac 3D ◽  
The Law ◽  
3D Software ◽  
Twin Tunnels

Due to the development of cities as well as rapid population growth, urban traffic is increasing nowadays. Hence, to improve traffic flow, underground structures such as metro, especially in metropolises, are inevitable. This paper is a research on the twin tunnels Of Isfahan's metro between Shariaty station and Azadi station from the North towards the South. In this study, simultaneous drilling of subway's twin tunnels is simulated by means of Finite Difference Method (FDM) and FLAC 3D software. Moreover, the lowest distance between two tunnels is determined in a way that the Law of Super Position could be utilized to manually calculate the amount of surface subsidence, resulted by drilling two tunnels, by employing the results of the analysis of single tunnels without using simultaneous examination and simulation. In this paper, this distance is called "effective distance". For this purpose, first, the optimum dimensions of the model is chosen and then, five models with optimum dimensions will be analyzed separately, each of which in three steps. The results of analyses shows that the proportions (L/D) greater than or equal 2.80, the Law of Super Position can be applied for prediction of surface subsidence, caused by twin tunnels' construction

Structure, Stability and Water Adsorption on Ultra-Thin TiO2 Supported on TiN

2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Adsorption ◽  
Chemical Potential ◽  
Energy Gap ◽  
Molecular Water ◽  
Structure Stability ◽  
Ambient Conditions ◽  
Rutile Structure ◽  
The Stability ◽  
The One

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>

The Demand For Money in Pakistan: Reply (Notes and Comments)

1975 ◽  
Vol 14 (3) ◽  
pp. 370-375
Author(s):  
M. A. Akhtar
Keyword(s):  
Interest Rates ◽  
Money Demand ◽  
Strong Support ◽  
Physical Capital ◽  
Careful Examination ◽  
Demand For Money ◽  
Weak Support ◽  
Complementarity Hypothesis ◽  
The Difference ◽  
The One

I am grateful to Abe, Fry, Min, Vongvipanond, and Yu (hereafter re¬ferred to as AFMVY) [1] for obliging me to reconsider my article [2] on the demand for money in Pakistan. Upon careful examination, I find that the AFMVY results are, in parts, misleading and that, on the whole, they add very little to those provided in my study. Nevertheless, the present exercise as well as the one by AFMVY is useful in that it furnishes us with an opportunity to view some of the fundamental problems involved in an empi¬rical analysis of the demand for money function in Pakistan. Based on their elaborate critique, AFMVY reformulate the two hypo¬theses—the substitution hypothesis and the complementarity hypothesis— underlying my study and provide us with some alternative estimates of the demand for money in Pakistan. Briefly their results, like those in my study, indicate that income and interest rates are important in deter¬mining the demand for money. However, unlike my results, they also suggest that the price variable is a highly significant determinant of the money demand function. Furthermore, while I found only a weak support for the complementarity between money demand and physical capital, the results obtained by AFMVY appear to yield a strong support for that rela¬tionship.1 The difference in results is only a natural consequence of alter¬native specifications of the theory and, therefore, I propose to devote most of this reply to the criticisms raised by AFMVY and the resulting reformulation of the two mypotheses.

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