ABSTRACT Using a high safety factor in construction without precise calculations imposes high costs on the execution project. Using a low safety factor exposes the project to a high risk of failure. Therefore, determining the impact of uncertain parameters greatly aids in designing with the least possible risk. The contribution of each parameter to uncertainty can be identified through sensitivity analysis. This paper considers the impact of the uncertainty of three parameters—elastic modulus, pipe thickness, and pipe diameter—on the buckling of a marine pipeline, as these three parameters significantly influence the geometry of the pipeline. Two analyses, First Order Second Moment (FORM) and Second Order Reliability Order (SORM), are employed for the sensitivity analysis of the pipeline parameters. The First Order Second Moment analysis provides four importance vectors, while the Second Order Reliability Order analysis yields only one importance index. The results indicate that the pipe diameter has a greater impact compared to the other two parameters. The smallest difference is observed between the elastic modulus and pipe thickness, suggesting that these two parameters have a similar level of sensitivity. The reliability index values in FORM and FOSM are distinct yet close to each other, with FOSM yielding a lower value.   INTRODUCTION Submarine pipelines are subjected to various forces of different natures during installation and operation, such as hoop stress, axial force, and so on. The high temperature and pressure gradient between the well and the terminal (platform or refinery) in gas transmission lines generates significant axial force in the pipeline. If the mentioned forces exceed a certain threshold, despite the friction of the seabed and the weight of the submerged pipeline, they can cause large deformations in the pipeline or, in other words, lead to pipeline buckling. The DNV-F-110 standard (DET NORSKE VERITAS) classifies this type of buckling as global buckling, which can be categorized into horizontal and vertical buckling based on the deformation mode (Shabani et al., 2017). Global buckling is a common and likely phenomenon that can occur during the operation of a pipeline. This phenomenon can lead to defects such as failure, bending, and so on in the pipeline (Karampour and Albermani, 2014). As accessible oil fields are depleted, the need for drilling at greater depths has increased, resulting in higher temperatures and pressures due to the transportation of hydrocarbon products. Consequently, the likelihood of global buckling occurring in deep waters has increased. Due to the lower critical temperature for lateral buckling compared to the critical temperature for vertical buckling, non-buried pipelines often face lateral buckling (Karampour et al., 2013). The presence of an initial vertical defect in a non-buried submarine pipeline makes the occurrence of vertical buckling possible. MATERIALS AND METHODS The marine pipeline studied in this research has a diameter of 0.816 meters, a thickness of 0.0242 meters, and a length of 40 meters. The Poisson's ratio of the pipeline is considered to be 0.3, and the thermal expansion coefficient is taken as 1.5 × 10^-6. The residual stress from the installation of the pipeline is not considered in this study due to its insignificance compared to other forces affecting the axial force. Horizontal compressive forces are considered with a high conservative coefficient. RESULTS Three parameters E, t, and D are geometric parameters of the underwater pipeline subjected to buckling. Among the three parameters mentioned, parameters of pipeline thickness and diameter are resistance variables, and elasticity modulus is the load resistance variable. The results show that the pipeline diameter is the most important among the mentioned parameters and the modulus of elasticity is the least important. In the analysis of FORM and FOSM, there are reliability indicators for both of them, which are the basic part of reliability evaluation by the two mentioned analyses. The reliability index values in FORM and FOSM are distinct but close values, which are lower in FOSM. According to Figure (2), the pipeline diameter is the most important variable of the defined limit state function. As it is clear, the smallest difference is between E and t, in other words, these two parameters are close to each other in terms of sensitivity, with the difference that one is a load variable and the other is a resistance variable. Also, this point can be concluded that the values elated to the importance index κ have a big difference with other importance indices and the rest of the importance indices have close values. DISCUSSION AND CONCLUSION Among the three mentioned parameters, the thickness and diameter of the pipeline are variables affecting resistance, while the modulus of elasticity is a variable affecting load resistance. The diameter of the pipeline holds the greatest importance among the mentioned parameters, while the modulus of elasticity is of lesser significance. The reliability index values in FORM and FOSM are distinct yet close to each other, with FOSM yielding a lower value. The approximate equality of the reliability index in the two analyses can be expressed by the difference in the importance vectors in the two analyses, and as the importance of the variables decreases, the difference becomes more pronounced. The values related to the importance index Kappa show a significant difference compared to other importance indices, while the remaining importance indices have values that are close to each other.

This paper establishes the first four Moment expansions to the order o(a-1) of Sta/Ö ta, where S´n =åni=1 Vi i=1 Yi is a simple random walk with E(Yi) = 0, and tα is a stopping time given by ta = inf {n ³1 : n + Sn + zn > a} where Sn = ån i= Xi is another simple random walk with E(Xi) = 0, and { zn, n³1} is a sequence of random variables satisfying certain assumptions. These Moment expansions complement the classical central limit theorem for a random number of i.i.d. random variables when the random number has the form ta, which arises from many sequential statistical procedures. They can be used to correct higher order bias and/or skewness in S´ta/Öta to make asymptotic approximation more accurate for small and moderate sample sizes.

Summary: To date, given the importance of drilling operations in the mining process and its impact on other phases of extraction, a number of studies have been carried out to investigate the influence of predicted bit rate and to determine the parameters influencing it. The estimation of rate of penetration (ROP) is an integral part of the design and planning stages of a mining project. To achieve a reasonable estimation of the ROP in the rock, it is essential to identify the influential factors, measure the effectiveness, and calculate the uncertainty of each set. The factors examined in current study include thrust, rock mass characteristics including rock mass indices, uniaxial compressive strength of intact rock, Schmidt hardness. Conducting a field study and laboratory testing, a database was compiled from the above parameters in Irankuh mine. Among these parameters, Schmidt hardness has the lowest standard deviation and highest reliability index and thrust has the highest standard deviation and lowest reliability index. This result indicated that in the independent parameters, Schmidt hardness has the lowest and thrust has the highest level of uncertainty. The standard deviation and reliability index of experimental models presented for the (ROP) are also at 53.02 and 0.729 percent respectively. So this relationship to predict the (ROP) in the lead and zinc Irankuh mine is confidence. Introduction: In this research, the necessary parameters to predict the drilling speed were selected in order to examine the effect of different geological, geo-mechanical and operational parameters of the drilling machine on ROP and prediction of the performance of the drilling machine. The model was obtained from effective parameters for the penetration rate. In the following, the reliability rate of the obtained model was calculated for the rate of permeability of drilling-bit in Irankouh mine to examine the uncertainty rate. Methodology and Approaches: The first-order Second-Moment method has the calculations that are relatively simple, and only the information needed to calculate it, is information related to the Moments of the input variables, so this method has been used in this research. Results and Conclusions: In this research, there is an uncertainty in registered information due to the environment to conduct the field observations and surveys and laboratory tests. Therefore, there is uncertainty and ambiguity in the developed equation to calculate the penetration rate in the Irankouh mine. So it has been tried to calculate the amount of ambiguity and, in fact, the number of variations that indicates the dispersion around the actual value of the penetration rate, using reliability analysis to FOSM first-order-Second-Moment method.

One of the most damaging natural disasters is an earthquake which random process of its motions has made predicting and preventing its occurrence impossible, but it is possible to reduce the probable damages caused by earthquakes through probabilistic seismic hazard studies. Iran is one the countries that always has been exposed to the damages of this natural phenomenon. The experiments of many countries that are at high risk of earthquakes, has shown that damages can be reduced when seismic hazard analysis is achieved in structural design process. Seismic hazard analysis requires the earthquake data and obviously more accurate data can lead to results with more precision. The magnitude, location and focal depth of the earthquakes are the most basic data that needs to be updated carefully. These parameters have a major role in the estimation of the probabilistic seismic hazard analysis in the different regions. The city of Tehran which is the capital and the most populous city of Iran was chosen as our study area. The current research includes a history of more than 300 earthquakes in the past 117 years, which has been analyzed for Tehran and its suburbs with the aim of conducting a new FOSM (First Order Second Moment) algorithm. In this method, four ground motion relationships with the same weight were also used. Based on given design seismic levels and the Iranian Standard No.2800, the present study had the PGA in two levels. The first level which is, Design Basis Earthquake (DBE) defines the peak horizontal accelerations with 10% probability of exceedance in 50 years that was expected to occur once in approximately 475 years. The Second is Maximum Considered Earthquake (MCE) that defines the peak horizontal accelerations with 2% probability of exceedance in 50 years which was expected to occur once in approximately 2,475 years. According to the FOSM algorithm, the estimated PGA for both levels was 0.30061 g and 0.55666 g, respectively.

Many books have been written to illustrate the position of the new technologies in teaching and learning a foreign or Second language (L2); nonetheless, most of these books have not been successful. The Handbook of Technology and Second Language Teaching and Learning edited by Caral A. Chapell and Shanon Sauro and published by Wiley Blackwell in 2017, provides a comprehensive overview of the various facets of the use of technology in teaching and learning an L2. This book has not been translated into Persian and no critical review has been published for it; accordingly, this study sought to both introduce and critically review this book. The current critical review revealed some advantages including comprehensiveness of the whole book, the expertise of the writers, up-to-dateness, content and format integrity, and the use of valid sources. The main criticisms are the exclusion of some of the very recent technologies, perhaps due to the ever-changing and exponentially volatile nature of the technological improvements and expansions, the introduction of too many technologies at the theoretical level without providing information about their practical use. Generally, the book is an invaluable and academically written source for L2 practitioners, postgraduate students, and researchers.