New Developments for the Description of Oil Leakages by Advective Migration From Submarine Pipelines

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Renan Martins Baptista ◽  
Ricardo Antonio Francisco Machado ◽  
Marintho Bastos Quadri ◽  
Ariovaldo Bolzan ◽  
André Lourenço Nogueira ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Immiscible Displacement ◽  
Preliminary Evaluation ◽  
Leakage Detection ◽  
New Developments ◽  
Gravitational Flow ◽  
The Third ◽  
Alternative Approach ◽  
High Standards ◽  
Good Agreement

The significant growth in offshore operations increases the risk of a pipeline rupture, even considering the high standards of safety involved. Throughout a submarine leakage, four different amounts of oil may be accounted. The first one is the oil volume released until the leakage detection. The second one is the volume leaked throughout mitigation initiatives (e.g., pump shutdown and valve closure). The third parcel is the amount released by gravitational flow. Finally, the fourth and last amount of oil is released due to the water-oil entrainment, generally known as advective migration. Normally, a considerable amount of oil is released in this step. It begins just after the internal pipeline pressure becomes equal to the external one. The present work continues to introduce a mathematical alternative approach, based on the theories of perturbation and unstable immiscible displacement, to accurately estimate the leakage kinetics and the amount of oil released by the advective migration phenomenon. Situations considering different hole sizes and thicknesses were tested experimentally and through simulations. Additional experiments were accomplished using smooth and rough edge surfaces, besides different slopes (using the horizontal plane as reference). Those experiments permitted a preliminary evaluation of the importance of these factors. The results obtained with the model showed good agreement with the experimental data in many situations considered.

New Developments for the Description of Oil Leakages by Advective Migration From Submarine Pipelines

2006 ◽  
Author(s):  
Renan Martins Baptista ◽  
Ricardo Antonio Francisco Machado ◽  
Marintho Bastos Quadri ◽  
Ariovaldi Bolzan ◽  
Andre´ Lourenc¸o Nogueira ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Immiscible Displacement ◽  
Preliminary Evaluation ◽  
Leakage Detection ◽  
New Developments ◽  
Gravitational Flow ◽  
The Third ◽  
Alternative Approach ◽  
High Standards ◽  
Good Agreement

The significant growing in offshore operations increases the risk of a pipeline rupture, even considering the high standards of safety involved. Throughout a submarine leakage, four different amounts of oil may be accounted. The first one is the oil volume released until the leakage detection. The second one is the volume leaked throughout mitigation initiatives (e.g. pump shut-down and valve closure). The third parcel is the amount released by gravitational flow. Finally, the fourth and last amount of oil is released due to the water-oil entrainment, generally known as advective migration. Normally, a considerable amount of oil is released in this step. It begins just after the internal pipeline pressure becomes equal to the external one. The present work continues to introduce a mathematical alternative approach, based on the theories of perturbation and unstable immiscible displacement, to accurately estimate the leakage kinetics and the amount of oil released by the advective migration phenomenon. Situations considering different holes sizes and thickness were tested experimentally and through simulations. Additional experiments were accomplished using smooth and rough edge surfaces, besides different slopes (using the horizontal plane as reference). Those experiments permitted a preliminary evaluation of the importance of these factors. The results obtained with the model showed good agreement with experimental data in many situations considered.

Mathematical Approach to Foresee the Oil Volume Leaked From a Submarine Pipeline in Case of Accident

2004 ◽  
Author(s):  
Renan Martins Baptista ◽  
Ricardo Antonio Francisco Machado ◽  
Marintho Bastos Quadri ◽  
Andre´ Lourenc¸o Nogueira ◽  
Toni Jefferson Lopes
Keyword(s):  
Oil Spills ◽  
Accurate Estimate ◽  
Immiscible Displacement ◽  
Submarine Pipeline ◽  
Continuous Increase ◽  
Oil Leakage ◽  
Oil Exploitation ◽  
Alternative Approach ◽  
High Standards ◽  
Offshore Oil

Even considering the high standards of safety involved, the significant and continuous increase in offshore oil exploitation rise the risks of a pipeline rupture, leading to oil spills. If an oil leakage occur, it is necessary to accurately quantify the volume released to correctly foresee the potential environmental impacts and define actions to soften them and clean up the oil spill. The present article introduces a mathematical alternative approach, based on the theories of perturbation and unstable immiscible displacement, to evaluate the occurrence or not of oil leakages through the advective migration phenomenon and estimate the oil volume released. According to preliminary results, the model shows to be promising in accurate estimate the oil volume leaked from a submarine pipeline in case of accident.

Boundary Friction for a Line Contact Model: An Empirical Approach

2015 ◽  
Vol 642 ◽  
pp. 8-12
Author(s):  
William W.F. Chong ◽  
Miguel de La Cruz
Keyword(s):  
Steel Plate ◽  
Friction Model ◽  
Boundary Friction ◽  
Slider Bearing ◽  
Base Oil ◽  
Atomic Force ◽  
Alternative Approach ◽  
Nanoscale Friction ◽  
Friction Measurements ◽  
Good Agreement

The paper introduces an alternative approach to predict boundary friction for rough surfaces at micros-scale through the empirical integration of asperity-like nanoscale friction measurements. The nanoscale friction is measured using an atomic force microscope (AFM) tip sliding on a steel plate, confining the test lubricant, i.e. base oil for the fully formulated SAE grade 10w40. The approach, based on the Greenwood and Tripp’s friction model, is combined with the modified Elrod’s cavitation algorithm in order to predict the friction generated by a slider-bearing test rig. The numerical simulation results, using an improved boundary friction model, showed good agreement with the measured friction data.

scholarly journals Causes of Regionalism. How ASEAN-China FTA Fits the (New) Wave of Regionalism?

2017 ◽  
Vol 17 (1) ◽  
pp. 66-94
Author(s):  
Ivana Miková
Keyword(s):  
Common Mechanism ◽  
Third Wave ◽  
New Wave ◽  
Negative Effects ◽  
Regional Trade ◽  
Multilateral Trade ◽  
The Third ◽  
Alternative Approach ◽  
General Logic ◽  
Balance Mechanism

AbstractThe main aim of this paper is to discuss standard explanations of the causes respective to each wave of economic regionalism and to introduce an alternative approach suggesting the existence of a common mechanism driving all three periods of intensified economic integration. This study argues for the general logic to economic regionalism based on the balance mechanism. Proposed mechanism embraces standard theoretical explanations and places them into a broader context of general encompassing logic common to all three occurrences of economic regionalism. For acquiring empirical evidence of this mechanism, all three waves of regionalism and their causes are analysed as well as on one particular case of the third wave of regionalism - ASEAN-China FTA. Central motivation is the existence of plethora of factors leading to the preference of the regional trade strategies in particular time periods without offering explanation common to all three main occurrences of regionalism. However, this study argues that every instance of economic turmoil leads to protectionist tendencies in the form of economic regionalism followed by the multilateral trade liberalisation mitigating negative effects of protectionist tendencies.

Aplikasi Teori Mahjub terhadap Pembaikan Sebutan Bunyi Bahasa Arab dalam Kalangan Pelajar Sabah - Application of Mahjub Theory in Arabic Pronunciation among Sabahan Students

2017 ◽  
Author(s):  
ISSRAQ BIN RAMLI ◽  
MOHD ZAKI ABD. RAHMAN
Keyword(s):  
Secondary School ◽  
Arabic Language ◽  
Future Research ◽  
Learning And Teaching ◽  
The Third ◽  
Alternative Approach ◽  
Holy Quran ◽  
Post Test ◽  
Arab Students ◽  
The Holy Quran

Terdapat banyak modul sebutan berada di pasaran yang memperkenalkan teknik pembelajaran dan pengajaran sebutan al-Quran al-Karim dan bahasa Arab. Ada yang menggunakan kaedah klasik, moden dan ada juga yang menggunakan kedua-dua kaedah secara komprehensif. Namun, amat sedikit kita lihat kaedah yang dapat memperbaiki sebutan dan menumpukan secara khusus teknik kepada pelajar bukan Arab. Sering kali diperkatakan tentang masalah sebutan pelajar Sabah tanpa membuat kajian secara terperinci dan ilmiah. Justeru, kajian ini dibuat untuk melihat masalah sebenar sebutan bunyi bahasa Arab pelajar Sabah dan seterusnya mengaplikasikan teori Mahjub (1993) untuk memperbaiki masalah sebutan bahasa Arab. Kajian ini dilakukan di sebuah sekolah menengah kebangsaan di Kota Kinabalu yang responden kajiannya ialah pelajar sekolah tingkatan empat. Objektif kajian adalah untuk mengenal pasti secara ilmiah permasalahan sebutan dalam kalangan pelajar Sabah dan mengaplikasi kaedah fonetik Mahjub, seterusnya melihat keberkesanan modul Mahjub sebagai instrumen terbaik memperbaiki sebutan pelajar Sabah. Kajian kualitatif ini menggunakan huruf-huruf konsonan yang sukar bagi pelajar asing yang dibuat oleh Mahjub (1993) yang menggunakan modul yang digunakan untuk memperbaiki sebutan Arab pelajar asing. Terdapat tiga langkah utama dalam kajian ini, iaitu rakaman ujian pertama (U1) sebagai sebutan bahasa Arab terkini pelajar Sabah, kemudian langkah kedua melaksanakan PdP berdasarkan PdP Mahjub dan langkah yang ketiga membuat rakaman ujian kedua (U2) untuk melihat keberhasilan teori Mahjub dalam memperbaiki sebutan pelajar Sabah. Hasil Kajian menunjukkan nilai yang sangat signifikan antara U1 dan U2. Daripada sembilan huruf yang diuji itu, konsonan ‘Ayn [ع] paling baik disebut oleh pelajar dan huruf Dad [ض] paling sukar disebut dalam U1. Dalam U2, huruf Ta’ [ط] paling sukar disebut dan huruf Sad [ص] paling mudah disebut. Dalam U1 Fathaṯ paling tinggi skor dengan 68.2 berbanding Sukun yang mempunyai skor paling rendah dengan 33.3. Secara puratanya, dalam U1 pelajar atau responden hanya mendapat purata sekitar 55 skor min bagi Dammaṯ dan Kasraṯ. Namun, pada U2 peningkatan masing-masing Dammaṯ dan Kasraṯ. mendapat skor yang hampir sama, iaitu 77.9 dan 76.9. Data menunjukkan bahawa Sukun paling bermasalah kepada responden dalam sebutan. Begitu juga terdapat perubahan yang signifikan dalam ujian kedudukan Fathaṯ, Dammaṯ dan Kasraṯ dari U1 kepada U2. Kajian menunjukkan bahawa teori Mahjub ini berhasil memperbaiki masalah sebutan dalam kalangan pelajar Sabah dan memberikan satu alternatif untuk diaplikasi dalam PdP pelajar dan membuka ruang kepada penulis lain untuk memanjangkan kajian pada masa akan datang. There are many modules/methods available in the market to introduce the techniques of learning and teaching the Holy Quran and the Arabic language. There are classical and modern methods in teaching the Holy Quran, and some might combine both classical and modern to help students to learn the Holy Quran. But there are only few methods which can really help to improve the pronunciation of Arabic especially among the non-Arab students who learn Arabic as a second language. This pronunciation problem is often discussed by the Arabic teachers but there are lack of proper studies to overcome this problem. Therefore, this study aims to identify specifically the pronunciation problem and to measure if the Maḥjub Theory can be applied to help in overcoming it. This study was conducted in a secondary school in Kota Kinabalu. The respondents were all Form 4 students. This qualitative study used the Maḥjub Module (1993) to rectify consonant letters that are difficult to pronounce by the Sabahan students. This study has undergone three phrases. The first phrase is U1 where the pre-test is carried out to evaluate the current capability of the respondents. The second phrase applied the Maḥjub Method in the PdP. The third phrase is U2 where the post-test was carried out after the Maḥjub Method was applied to the respondents. This study showed significant value between U1 and U2. Nine consonant letters were tested in this study. In U1, ‘Ayn [ع]was the easiest to pronounce and Dad [ض] was the most difficult to pronounce by the respondents. In U2, Ta’ [ط] was the hardest to pronounce and Sad [ص] was the easiet. In U1, Fathaṯ was the highest with 68.2 score as compared to Sukun with 33.3 score. Overall, respondents scored a mean of 55 for Dammaṯ and Kasraṯ in U1. However, in U2, Dammaṯ and Kasraṯ showed very close score as of 77.9 and 76.9. The data also showed that Sukun is the hardest part for the respondents.This study had proved that the Maḥjub Method is enabled to enhance and improve the difficulty in pronunciation among the students in Sabah. Therefore, the Mahjub Method gives educators an alternative approach to apply in their teaching and also other researchers for ideas to carry out future research in this field.

scholarly journals Basic philosophical texts in Medieval Serbia

Balcanica ◽  
2008 ◽  
pp. 79-102
Author(s):  
Boris Milosavljevic
Keyword(s):  
Fourteenth Century ◽  
Social Event ◽  
Philosophical Text ◽  
Highly Educated ◽  
The Third ◽  
Philosophical Texts ◽  
High Standards ◽  
Theological Debate ◽  
Christian Platonism ◽  
Central Social

Medieval Serbian philosophy took shape mostly through the process of translating Byzantine texts and revising the Slavic translations. Apart from the Aristotelian terminological tradition, introduced via the translation of Damascene?s Dialectic, there also was, under the influence of the Corpus Areopagiticum and ascetic literature, notably of John Climacus? Ladder, another strain of thought originating from Christian Platonism. Damascene?s philosophical chapters, or Dialectic, translated into medieval Serbian in the third quarter of the fourteenth century, not only shows the high standards of translation technique developed in Serbian monastic scriptoria, but testifies to a highly educated readership interested in such a complex theologico-philosophical text with its nuanced terminology. A new theological debate about the impossibility of knowing God led to Gregory Palamas? complex text, The Exposition of the Orthodox Faith. Philosophical texts were frequently copied and much worked on in medieval Serbia, but it is difficult to infer about the actual scope of their influence on the formation and articulation of the worldview of medieval society. As a result of their demanding theoretical complexity, the study of philosophy was restricted to quite narrow monastic, court and urban circles. However, the strongest aspect of the influence of Byzantine thought on medieval society was the liturgy as the central social event of the community. It was through the liturgy that the wording of the translated texts influenced the life of medieval Serbian society.

A Two-Dimensional Potential Flow Model of the Wave Field Generated by a Semisubmerged Body in Heaving Motion

1988 ◽  
Vol 32 (02) ◽  
pp. 83-91
Author(s):  
X. M. Wang ◽  
M. L. Spaulding
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Potential Flow ◽  
Flow Model ◽  
Second Order ◽  
Two Dimensional ◽  
Third Order ◽  
The Third ◽  
Potential Flow Model ◽  
Good Agreement

A two-dimensional potential flow model is formulated to predict the wave field and forces generated by a sere!submerged body in forced heaving motion. The potential flow problem is solved on a boundary fitted coordinate system that deforms in response to the motion of the free surface and the heaving body. The full nonlinear kinematic and dynamic boundary conditions are used at the free surface. The governing equations and associated boundary conditions are solved by a second-order finite-difference technique based on the modified Euler method for the time domain and a successive overrelaxation (SOR) procedure for the spatial domain. A series of sensitivity studies of grid size and resolution, time step, free surface and body grid redistribution schemes, convergence criteria, and free surface body boundary condition specification was performed to investigate the computational characteristics of the model. The model was applied to predict the forces generated by the forced oscillation of a U-shaped cylinder. Numerical model predictions are generally in good agreement with the available second-order theories for the first-order pressure and force coefficients, but clearly show that the third-order terms are larger than the second-order terms when nonlinearity becomes important in the dimensionless frequency range 1≤ Fr≤ 2. The model results are in good agreement with the available experimental data and confirm the importance of the third order terms.

A Preliminary Evaluation of the iPad as a Tool for Learning and Teaching

2013 ◽  
pp. 154-168
Author(s):  
Sue Gregory ◽  
Tony Brown ◽  
Mitchell Parkes
Keyword(s):  
Distance Education ◽  
Pilot Study ◽  
Social Networking ◽  
Large Distance ◽  
Point Of View ◽  
Preliminary Evaluation ◽  
Laptop Computers ◽  
Learning And Teaching ◽  
The Third ◽  
Education Study

In May 2010, the release of the iPad in Australia brought a whole new dimension to learning. This chapter presents the preliminary findings of a pilot study conducted at a large distance education university designed to explore the use of the iPad as a tool for learning from three perspectives. The first is the use of the iPad from a lecturer’s point of view, outlining how it can be used to enhance the task of teaching in distance education. The second is from a student’s point of view, exploring how the iPad can assist in distance education study. The third examines the iPad from an insider perspective, reviewing the variety of apps available including those for social networking. The overall impression is that the iPad has great potential as a tool for learning but it will not necessarily reduce the need for desktop or laptop computers.

Modelling of an alternating oxidation ditch system

1999 ◽  
Vol 39 (4) ◽  
pp. 169-176 ◽  
Author(s):  
A. Stamou ◽  
A. Katsiri ◽  
I. Mantziaras ◽  
K. Boshnakov ◽  
B. Koumanova ◽  
...  
Keyword(s):  
Pilot Plant ◽  
High Speed ◽  
Dispersion Coefficient ◽  
Carbon Oxidation ◽  
Correction Factors ◽  
Oxidation Ditch ◽  
The Third ◽  
Basic Equations ◽  
Short Presentation ◽  
Good Agreement

This paper presents a mathematical model for an alternating oxidation ditch system, performing carbon oxidation-nitrification, denitrification and settling. The model consists of 1-dimensional mass balance (convection-dispersion) equations, based on the IAWPRC activated sludge model No 1. The data used for the calibration and the application of the model, are collected from a pilot plant. The present work consists of 3 parts. In the first part a brief description of the pilot plant is made. The second part deals with a short presentation of the basic equations and the boundary conditions of the model. The calibration and application of the model with the corresponding conclusions are contained in the third part. In the calibration, the values of the dispersion coefficient, E, and the correction factors α and β of the equation of the aeration equipment (rotors) have been determined equal to E=170000 m2 day−1, β=0.85 and α=0.3 and 0.825, for the operation of the rotors in the low and high speed, respectively. The application of the model shows that predicted effluent concentration values are in a very good agreement with experiments.

Knowledge Management and Lifelong Learning in Archival Heritage

2011 ◽  
pp. 116-131
Author(s):  
Triantafillia Kourtoumi
Keyword(s):  
Knowledge Management ◽  
Knowledge Sharing ◽  
Lifelong Learning ◽  
Social Benefits ◽  
Potential Contribution ◽  
Technology Research ◽  
Digital Collections ◽  
New Developments ◽  
The Third ◽  
Educational Perspective

Archives have a key role to play in underpinning learning in its broadest sense, both as a formal activity within an institution and informally within the community. This is becoming especially important in an increasingly KM-based environment. This chapter provides an overview of technologies that can be applied to archival knowledge management. Furthermore, it assesses their actual or potential contribution to the basic processes of knowledge sharing within archival organizations, with a focus on lifelong learning. The scope of the first section (the screens) is to identify new developments that seem to be significant and to relate them to technology research in the archival field. The second section (the frames) discusses the concepts supporting digital collections by integrating collections of digitized archival resources to create new services and infrastructures. The third section (the agendas) analyses-from the educational perspective of lifelong learning-important social benefits, both quantitatively and qualitatively, of developing new infrastructures for accessing and using archival resources.

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