Engineering Design of Rock Slope Reinforcement Based on Non-Linear Joint Strength Model

Optimum dimensioning of bolts or anchors for the reinforcement of slopes in jointed rock masses, requires compatible strength-deformation data, for both the rock joints and the reinforcing elements. Most types of rock joints behave in non- linear fashion and, thus, realistic modelling can have serious implications in the design, both from the economical and the technical standpoints. This paper will present, briefly, the principles of a constitutive model of joint shear behaviour and a method for optimum bolt or anchor design. The implications of non-linear joint behaviour will be demonstrated with numerical examples. Finally, a case study of slope stabilization, in which the method was adopted, will be reported

Impact on audit quality: assessing internal auditors behavior in the banking sector. A theoritical approach and an empirical analysis using evidence from Greece

Σκοπός της έρευνας είναι να μελετήσει και να αναλύσει τους διάφορους παράγοντες που ενδεχομένως επηρεάζουν τη συμπεριφορά των εσωτερικών ελεγκτών και την ποιότητα του ελεγκτικού έργου. Η ανάλυση θα αναδείξει τους παράγοντες που οδηγούν στη δυσλειτουργική συμπεριφορά των ελεγκτών, η οποία κατ' επέκταση οδηγεί στην ανεπιτυχή ολοκλήρωση του ελεγκτικού τους έργου. Η εμπειρική μελέτη αποσκοπεί στην αξιολόγηση της συμπεριφοράς των ελεγκτών σε σχέση με τους παράγοντες που επιβάλλονται από το τμήμα ελέγχου της εταιρείας, όπως η "πίεση των χρονικών προθεσμιών", η "πίεση του χρονικού προϋπολογισμού" και η "διαδικασία αξιολόγησης της απόδοσης". Η μελέτη επιδιώκει επίσης να εξηγήσει τυχόν διαφορές στη συμπεριφορά των ελεγκτών ανάλογα με το ιεραρχικό τους επίπεδο. Για την επίτευξη του σκοπού της μελέτης συλλέχθηκαν δεδομένα από τις απαντήσεις σε ερωτηματολόγιο που δόθηκε σε εσωτερικούς ελεγκτές, όλων των επιπέδων, στον Ελληνικό τραπεζικό τομέα. Τα αποτελέσματα έδειξαν ότι οι εσωτερικοί ελεγκτές είναι ευάλωτοι να επιδείξουν δυσλειτουργική συμπεριφορά όταν τους ζητείται να εργαστούν ταχύτερα προκειμένου να τηρήσουν τις αυστηρές προθεσμίες. Επιπλέον, οι ελεγκτές είναι πιο πιθανό να επιδείξουν δυσλειτουργική συμπεριφορά εάν τους ανατίθεται μεγάλος αριθμός ετήσιων ελεγκτικών έργων. Επιπλέον, οι ελεγκτές ασκούν ελέγχους με βάση τον κίνδυνο, επικεντρώνοντας την προσοχή τους σε περιοχές υψηλού κινδύνου και διενεργώντας ανεπαρκείς ελέγχους σε περιοχές χαμηλού κινδύνου, προκειμένου να ακολουθήσουν τους αυστηρούς χρονικούς περιορισμούς. Επιπρόσθετα, τα αποτελέσματα της μελέτης έδειξαν ότι οι αυστηροί χρονικοί περιορισμοί και η έλλειψη συνεργασίας μεταξύ ελεγκτών και προϊστάμενων είναι παράγοντες που προκαλούν πρόωρη ολοκλήρωση των ελεγκτικών βημάτων και, ως εκ τούτου, δυσλειτουργική συμπεριφορά. Τέλος, τα στοιχεία δείχνουν ότι αποτελεί κοινή πρακτική των ελεγκτών για χάρη της έγκαιρης ολοκλήρωσης των ελεγκτικών έργων, να υποκαταγράφουν τον απαιτούμενο χρόνο δουλεύοντας στον προσωπικό τους χρόνο, σε μια προσπάθεια βελτίωσης της αξιολογήσης της απόδοσής τους.The aim of the research is to study and analyze different factors that are potentially involved in influencing the internal auditors’ behavior and the quality of the audit work. The analysis will highlight the factors that lead to auditors' dysfunctional behavior which by extension leads to the unsuccessful completion of their audit work. The empirical study aims to evaluate the auditors' behavior in relation to factors imposed by the audit department of the company such as “time deadline pressure”, “time budget pressure” and “performance evaluation process”. The study also seeks to explain any differences in auditors' behavior according to their hierarchical level. Data was gathered from responses to a questionnaire that was given to internal auditors, of all levels, in the Greek banking sector in order to achieve the study’s purpose. The results showed that internal auditors are vulnerable to perform dysfunctional behavior when they are inquired to work faster in order to meet the strict time deadlines. Furthermore auditors are more likely to engage in dysfunctional conduct if they are assigned with a big number of annual audit assignments. Moreover, auditors exercise risk- based audits by concentrating on high- risk areas and performing poor inspections in low- risk areas in order to follow the strict time constraints. Additionally the study’s results showed that severe time limitations and the lack of collaboration between auditors and managers are factors causing early signing- off of the audit steps and, as a result, dysfunctional behavior. Finally, outcomes demonstrate that is a common practice for auditors to underreport the chargeable time by working on their personal time, for the sake of timely completion of audit projects in an effort to improve their performance evaluations

Desain Dual Fuel LNG Carrier untuk Suplai Bahan Bakar LNG di Alur Pelayaran Barat Surabaya (APBS)

Kebutuhan masyarakat dunia akan sumber energi terus meningkat dari tahun ke tahun, baik bahan bakar minyak maupun gas. Saat ini bahan bakar minyak sudah banyak digantikan dengan bahan bakar gas seperti LNG dan LPG. Kelebihan dari LNG yaitu memiliki potensi ekonomi yang lebih murah dibandingkan dengan bahan bakar minyak apabila digunakan sebagai bahan bakar penggerak kapal, LNG memenuhi sebagian besar persyaratan emission control area (ECA), teknologi yang digunakan sudah terbukti dan sudah banyak dipakai, dan memiliki fleksibilitas dalam hal bunkering. Meningkatnya jumlah kunjungan kapal di Alur Pelayaran Surabaya Barat akan berbanding lurus dengan polusi yang akan dihasilkan oleh gas buang dari kapal. Oleh karena itu, banyak pemilik kapal mulai berpidah dari mesin diesel ke mesin dual fuel. Untuk mempermudah dalam transfer bahan bakar LNG dari LNG Bunkering Onshore ke kapal yang membutuhkan bahan bakar LNG, maka dari itu dalam tugas akhir ini mengusulkan Desain Dual Fuel LNG Carrier untuk suplai bahan bakar LNG di alur pelayaran barat Surabaya, dengan adanya Kapal LNG Carrierini dapat mempercepat dan meningkatkan fleksibilitas kapal untuk proses pengisian bahan bakar. Payload dari Dual Fuel LNG Carrier ini didapatkan berdasarkan data kunjungan kapal di Pelabuhan Tanjung Perak yang dihitung kebutuhan bahan bakar LNG untuk setiap harinya. Kemudian ditentuakan ukuran tanki LNG yang sesuai untuk mencari ukuran utama kapal, sehingga didapatkan ukuran utama kapal dari layout tangki LNG type C 1500 m^3. Setelah itu dilakukan perhitungan teknis berupa perhitungan berat, trim, freeboard, dan stabilitas. Ukuran utama yang didapatkan adalah Lpp =52 m; B = 14,8 m; H = 6,2 m; T = 3,5 m. Tinggi freeboard minimum sebesar 613,08mm, besarnya tonnase kapal adalah 1539,376 GT, dan kondisi stabilitas Dual Fuel LNG Carrier memenuhi kriteria Intact Stability (IS) Code Reg. III/3.1.Analisis ekonomis yang dilakukan adalah memperhitungkan biaya pembangunan (investasi), biaya operasional, serta estimasi Breakeven Point (BEP). Biaya pembangunan Dual Fuel LNG Carrier ini sebesar Rp.37.837.629.171dan estimasi BEP pada bulan ke-53 dengan estimasi pengambilan keuntungan bersih sebesar Rp 726.737.621,15. Penggunaan bahan bakar dual fuel (LNG dan MDO) lebihhemat 70% dibandingkan dengan menggunakan bahan bakar konvensoinal yaitu MDO. ===================================================================== The need of the world community on energy sources increases from year to year, both oil fuel and gas. Currently, oil fuel has been replaced with many gas fuels such as LNG and LPG. The advantage of LNG is that it has a cheaper economic potential compared to fuel oil when used as a ship propulsion fuel, LNG meets most of the emission control area (ECA) requirements, the technology used has been proven and widely used, and has flexibility in terms of bunkering. The increasing number of ship visits in the West Surabaya shipping line will be directly proportional to the pollution that will be generated by exhaust gasses from the vessel. Referring to these circumstances, many shipowners began to move from diesel engine to dual fuel engine. To facilitate the transfer of LNG fuel from LNG Bunkering Onshore to vessel that requires LNG fuel, therefore in this final project proposes Dual Fuel LNG Carrier Design to supply LNG fuel in West Surabaya shipping line, in the presence of Carrierini LNG Vessel can accelerate and increase the flexibility of ships for refueling. Payload from Dual Fuel LNG Carrier was obtained based on ship visit data at Port of Tanjung Perak which calculated the needs of LNG fuel for every day. Then, it was determined the appropriate size of LNG tank to find the main size of the ship, and it was obtained the main size of the vessel from the layout of LNG tank type C 1500 m3. After that, technical calculation was done in terms of weight, trim, freeboard, and stability. The main size obtained was Lpp = 52 m; B = 14.8 m; H = 6.2 m; T = 3.5 m. The height minimum freeboard was 613.08 mm, the ship's tonnage was 1539,376 GT, and the stability condition of Dual Fuel LNG Carrier meets the criteria of Intact Stability (IS) Code Reg. III / 3.1.Tht economic calculation and analysis such as building cost, operational cost and Break Even Point (BEP) estimation. The building cost is estimated at Rp.37.837.629.171and BEP within 53 months with estimated revenue at Rp 726.737.621,15. The use of dual fuel (LNG and MDO) is more cheaper 70% than using conventional fuel (MDO)

Desain Dual Fuel LNG Carrier untuk Suplai Bahan Bakar LNG di Alur Pelayaran Barat Surabaya (APBS)

Kebutuhan masyarakat dunia akan sumber energi terus meningkat dari tahun ke tahun, baik bahan bakar minyak maupun gas. Saat ini bahan bakar minyak sudah banyak digantikan dengan bahan bakar gas seperti LNG dan LPG. LNG memenuhi sebagian besar persyaratan emission control area (ECA). Oleh karena itu, banyak pemilik kapal mulai berpidah dari mesin diesel ke mesin dual fuel, maka dari itu dalam penelitian ini mengusulkan Desain Dual Fuel LNG Carrier untuk suplai bahan bakar LNG di alur pelayaran barat Surabaya, dengan adanya Kapal LNG Carrier ini dapat mempercepat dan meningkatkan fleksibilitas kapal untuk proses pengisian bahan bakar. Payload dari Dual Fuel LNG Carrier ini didapatkan berdasarkan data kunjungan kapal di Pelabuhan Tanjung Perak yang dihitung kebutuhan bahan bakar LNG untuk setiap harinya. Kemudian ditentuakan ukuran tanki LNG yang sesuai untuk mencari ukuran utama kapal, sehingga didapatkan ukuran utama kapal dari layout tangki LNG type C 1500 15m3"> . Setelah itu dilakukan perhitungan teknis berupa perhitungan berat, trim, freeboard, dan stabilitas. Ukuran utama yang didapatkan adalah Lpp =52 m; B = 14,8 m; H = 6,2 m; T = 3,5 m. Tinggi freeboard minimum sebesar 613,08 mm, besarnya tonnase kapal adalah 1539,376 GT, dan kondisi stabilitas Dual Fuel LNG Carrier memenuhi kriteria Intact Stability (IS) Code Reg. III/3.1. Analisis ekonomis yang dilakukan adalah memperhitungkan biaya pembangunan (investasi), biaya operasional, serta estimasi Breakeven Point (BEP). Biaya pembangunan Dual Fuel LNG Carrier ini sebesar Rp. 37.837.629.171 dan estimasi BEP pada bulan ke-53 dengan estimasi pengambilan keuntungan bersih sebesar Rp 726.737.621,15. Penggunaan bahan bakar dual fuel (LNG dan MDO) jauh lebih hemat dibandingkan dengan menggunakan bahan bakar konvensoinal yaitu MDO

Critical Reynolds number for nonlinear flow through rough-walled fractures: The role of shear processes

This paper experimentally investigates the role of shear processes on the variation of critical Reynolds number and nonlinear flow through rough-walled rock fractures. A quantitative criterion was developed to quantify the onset of nonlinear flow by comprehensive combination of Forchheimer's law and Reynolds number. At each shear displacement, several high-precision water flow tests were carried out with different hydraulic gradients then the critical Reynolds number was determined based on the developed criterion. The results show that (i) the Forchheimer's law was fitted very well to experimental results of nonlinear fluid flow through rough-walled fractures, (ii) the coefficients of viscous and inertial pressure drops experience 4 and 7 orders of magnitude reduction during shear displacement, respectively, and (iii) the critical Reynolds number varies from 0.001 to 25 and experiences 4 orders of magnitude enlargement by increasing shear displacement from 0 to 20 mm. These findings may prove useful in proper understanding of fluid flow through rock fractures, or inclusions in computational studies of large-scale nonlinear flow in fractured rocks

Measurement of gauge blocks by interferometry

The key comparison EURAMET.L-K1.2011 on gauge blocks was carried out in the framework of a EURAMET project starting in 2012 and ending in 2015. It involved the participation of 24 National Metrology Institutes from Europe and Egypt, respectively. 38 gauge blocks of steel and ceramic with nominal central lengths between 0.5 mm and 500 mm were circulated. The comparison was conducted in two loops with two sets of artifacts. A statistical technique for linking the reference values was applied. As a consequence the reference value of one loop is influenced by the measurements of the other loop although they did not even see the artifacts of the others. This influence comes solely from three "linking laboratories" which measure both sets of artifacts. In total there were 44 results were not fully consistent with the reference values. This represents 10% of the full set of 420 results which is a considerable high number. At least 12 of them are clearly outliers where the participants have been informed by the pilot as soon as possible. The comparison results help to support the calibration and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA

A fully coupled hydro-mechanical model for the modeling of coalbed methane recovery

Most coal seams hold important quantities of methane which is recognized as a valuable energy resource. Coal reservoir is considered not conventional because methane is held adsorbed on the coal surface. Coal is naturally fractured, it is a dual-porosity system made of matrix blocks and cleats (i.e fractures). In general, cleats are initially water saturated with the hydrostatic pressure maintaining the gas adsorbed in the coal matrix. Production of coalbed methane (CBM) first requires the mobilization of water in the cleats to reduce the reservoir pressure. Changes of coal properties during methane production are a critical issue in coalbed methane recovery. Indeed, any change of the cleat network will likely translate into modifications of the reservoir permeability. This work consists in the formulation of a consistent hydro-mechanical model for the CBM production modeling. Due to the particular structure of coal, the model is based on a dual-continuum approach to enrich the macroscale with microscale considerations. Shape factors are employed to take into account the geometry of the matrix blocks in the mass exchange between matrix and fractures. The hydro-mechanical model is fully coupled. For example, it captures the sorption-induced volumetric strain or the dependence of permeability on fracture aperture, which evolves with the stress state. The model is implemented in the finite element code Lagamine and is used for the modeling of one production well. A synthetic reservoir and then a real production case are considered. To date, attention has focused on a series of parametric analyses that can highlight the influence of the production scenario or key parameters related to the reservoir

Evaluation of full scale shear performance of tension anchor foundations: Load displacement curves and failure criteria

One of the biggest challenges faced by the offshore wave and tidal energy industry is the high cost of constructing and installing offshore foundations. Foundations based on post tensioned pile anchors can be effectively proposed to tackle this issue. A series of full-scale direct shear tests were performed on-shore to evaluate the shear resistance of post-tensioned pile anchor foundations designed for securing tidal turbine devices to a rock seabed. We focused, in particular, on the primary shear resistance mechanism of post-tensioned anchors, by applying a vertical force which mobilizes, a frictional force able to resist horizontal thrusts. Different load paths, involving monotonic or cyclic loading, were applied; several configurations for the footing of the foundation were tested. The footing stress-displacement behavior and the stress conditions at sliding failure from a number of different testing configurations were compared and analyzed. A marked consistency with the shear performance of natural rock joints was identified. This allows the behavior of tension pile foundations subjected to substantial horizontal loads to be modelled using relationships developed for rock joints, widely available in the literature. Additionally, the results obtained from different tests were also collated considering the various configurations adopted for the foundation-rock system and the applied load paths, to identify the factors that affect the shear resistance of the foundation.