Wind Loading—Practicing Engineers and the Code

In modern structural codes, the reference value of the snow load on roofs is commonly given as the product of the characteristic value of the ground snow load at the construction site multiplied by the shape coefficient. The shape coefficient is a conversion factor which depends on the roof geometry, its wind exposure, and its thermal properties. In the Eurocodes, the characteristic roof snow load is either defined as the value corresponding to an annual probability of exceedance of 0.02 or as a nominal value. In this paper, an improved methodology to evaluate the roof snow load characterized by a given probability of exceedance (e.g., p=0.02 in one year) is presented based on appropriate probability density functions for ground snow loads and shape coefficients, duly taking into account the influence of the roof’s geometry and its exposure to wind. In that context, the curves for the design values of the shape coefficients are provided as a function of the coefficient of variation (COVg) of the yearly maxima of the snow load on the ground expected at a given site, considering three relevant wind exposure conditions: sheltered or non-exposed, semi-sheltered or normal, and windswept or exposed. The design shape coefficients for flat and pitched roofs, obtained considering roof snow load measurements collected in Europe during the European Snow Load Research Project (ESLRP) and in Norway, are finally compared with the roof snow load provisions given in the relevant existing Eurocode EN1991-1-3:2003 and in the new version being developed (prEN1991-1-3:2020) for the “second generation” of the Eurocodes.

In the history of civil engineering, the structures were usually designed considering only static load factor. Later due to research in the civil engineering field, it was explored that the structures are also acted upon by several other loads which included seismic loads, wind loads, snow loads and many others depending upon the dimensions of the structure, location of the structure, type of the ground profile, etc. Hence this brought in the process of analyzing a structure for different types of loads and designing the structure for the critical load case of which dynamic load is considered as one of the important load for which the structure should be analyzed and designed. The main aim of this research work is to investigate the seismic performance of a multistoried reinforced concrete moment resisting framed building under static and dynamic loading as per Bangladesh National Building Code (BNBC, 2006). Static seismic load has been applied to the structure according to Equivalent static force (ESF) method. On the other hand, response spectrum (RS) method has been performed for the application of dynamic loading. The present study focuses on investigating the variation of storey-displacement and storey drift for each storey, base shear, bending moments and shear forces in columns at different storey level. Finally, a comparative study has been carried out between static and dynamic analysis. Based on computing modeling output data, it has been found that the base shear obtained from RS analysis is less compared to ESF method. Maximum storey-displacement obtained from dynamic RS analysis is about 78% of that of static analysis. At the same time, in case of maximum bending moment in an interior column, the dynamic value is approximately 87% of the static value.

This Study examined Community Development Programmes and Leadership Capacity Building of Community Leaders in Bayelsa State of Nigeria. The study adopted a descriptive survey design. The population of the study comprises the 1,294 Paramount Rulers and Community Development Committee (CDC) Chairmen in the state. The simple random sampling technique was applied to select 200 respondents from each of the senatorial districts that make up Bayelsa State (Bayelsa Central, Bayelsa East and Bayelsa West) to realize a sample size of 600. The instrument used for data collection was a questionnaire. The reliability coefficient index of the instrument was 0.85. Three research questions were posed. They were analyzed using frequencies and weighted mean. The findings revealed amongst others that: cultural education programmes, environment/sanitation education programmes and peace/conflict resolution education programmes build the capacity of Community Leaders on cultural values for peaceful coexistence amongst others. Based on the findings, the Researcher recommended amongst others that: Paramount Rulers and Community Development Committee (CDC) Chairmen should recommend to the state government on adding peace education to the primary and secondary school curriculum as this would bring lasting peace to the various local government areas of Bayelsa State and Nigeria at large.

The paper describes a Coalition Project for the reform of engineering education in the state of Santa Catarina, in the southern part of Brazil. New teaching/learning methodologies are conceived for the academic formation of a professional tuned up to the technological dynamic of his/her time and to the challenges to the engineering profession anticipated for the coming century. The approaches described are the backbone of a project for the restructuring of engineering education, led by the Federal University of Santa Catarina. The project unfolds over three major actions. The first is connected with the election of engineering as a career. A methodology for the search of talents is proposed; it is based upon the Synthesis of Multiple Intelligence and is meant to be taken to high school students as a motivating and probing contact with the challenges of the engineering profession. The second action, that complements the first, involves the early exposure of engineering students to engineering themes and problems during the first part of the course. The study of Mathematics, Physics, Chemistry, etc. shall be coupled to an initiation at engineering problems and methods. This kind of approach and its methodology should facilitate the insertion of the students into the context of engineering problems from the beginning of his/her academic trajectory. Finally, the last action should be developed at the level of the applied courses.

Various skin defects resulting from all kinds of acute and chronic injury factors, such as mechanical injuries, burns, chronic ulcer and body tumor resection that is very common. Compared to the traditional methods, the advent of skin tissue engineering provides an ideal and promising way for the repair of these skin defects. In the past decades, several kinds of products have been developed and presented good clinical effects. However, some basic science problems emerged and blocked the traditional process of some tissue-engineered skin products. This paper aims to present the critical problems of skin tissue engineering, offering some thought of the related researchers and readers. Key words: Tissue engineering; Skin; Stem cells; Wound repair; Growth factor; Translational medicine

Special Issue on UHV air insulation: Physical and Engineering Research

Snow induced collapse of hail protection canopies

The Indonesian SNI 7973:2013 standard for wood design specification was an adopted standard from the USA national design specification (NDS) 2012. However, due to the climate differences between USA and Indonesia, the SNI 7973:2013 standard should be further modified in order to meet the climate condition in Indonesia. Format conversion factor (K F ) and reliability normalization factor (K R ) specified in the ASTM D 5457 standard contained the snow load for the duration of load factor. Therefore, the objectives of this study were (1) to replace snow load with occupancy live load to revise K F , (2) to use the revised K F and safety factors for softwood and hardwood to perform the reliability analysis on calculated resistance factors (f c ), (3) calculate the new K R values using the revised f c . The result of FORM reliability analysis showed that there were, on the average, 15 and 26% increases of the calculated K R values, respectively, for softwood and hardwood, over the calculated K R values according to the ASTM D 5457 standard for each given coefficient of variation of material resistance distribution.

Recently, the numerical modelling and simulation for anomalous subdiffusion equation (ASDE), which is a type of fractional partial differential equation( FPDE) and has been found with widely applications in modern engineering and sciences, are attracting more and more attentions. The current dominant numerical method for modelling ASDE is Finite Difference Method (FDM), which is based on a pre-defined grid leading to inherited issues or shortcomings. This paper aims to develop an implicit meshless approach based on the radial basis functions (RBF) for numerical simulation of the non-linear ASDE. The discrete system of equations is obtained by using the meshless shape functions and the strong-forms. The stability and convergence of this meshless approach are then discussed and theoretically proven. Several numerical examples with different problem domains are used to validate and investigate accuracy and efficiency of the newly developed meshless formulation. The results obtained by the meshless formulations are also compared with those obtained by FDM in terms of their accuracy and efficiency. It is concluded that the present meshless formulation is very effective for the modeling and simulation of the ASDE. Therefore, the meshless technique should have good potential in development of a robust simulation tool for problems in engineering and science which are governed by the various types of fractional differential equations.

در جامعه اسلامی برای بستر سازی اندیشه مهندسی اجتماعی خردنگر و مشارکت مدنی، نهادهایی وجود دارد که سابقه هزار و چهار صد ساله دارد. مساجد که مهمترین محل حضور توده های مردم در هر عصری بوده و هستند، با ایجاد زمینه برای فعالیت های جمعی داوطلبانه، می توانند نقش مؤثری در توسعه محله ای داشته باشند. تحقیق حاضر با بررسی فعالیت های چندگانه مساجد در سطح محله در هشت محور کلی (نقش مسجد در غنی سازی اوقات فراغت، ایجاد فضای فرهنگی، ارائه کمک های مالی، برگزاری مراسم و جلسات مذهبی – فرهنگی، افزایش میزان مشارکت ساکنان محله، ارائه کمک های مشاوره ای، اولویت سنجی مسائل، مشکلات و نیازهای محله، ارتقاء امنیت فردی و اجتماعی از طریق افزایش نظارت درونی و بیرونی) وهمچنین بررسی استقبال مردم محله از فعالیت ها، برنامه ها و بستر های فراهم شده توسط مساجد، به تحلیل نقش مسجد به عنوان گسترده ترین شبکه فراگیر اجتماعی و نقش آفرینی آن در توسعه ی محله ای در مشهد مقدس می پردازد. در این تحقیق ازروش توصیفی – تحلیلی سود جسته شده و تکنیک پرسشنامه و مصاحبه، ابزار نیل به اهداف بوده است.به همین منظور، به تکمیل پرسشنامه به حجم نمونه ای برابر با 385 نفر از شهروندان ونظر خواهی از تعدادی از کارشناسان و متخصصان مرتبط با موضوع مبادرت گردیده و جهت تحلیل داده ها از نرم افزار spssاستفاده شده است. به منظور توصیف داده ها از شاخص های میانگین، میانه، انحراف استاندارد ، فراوانی و درصد استفاده شده و در سطح استنباطی برای بررسی روابط ، از آزمون کی دو استفاده شده است. نتایج تحقیق نشان می دهد، مساجد در محورهای مورد بررسی، برنامه های مؤثری در جهت توسعه محله ای دارند. از طرف دیگر ساکنان محله از بسترهای فراهم شده توسط مسجد استفاده کرده و از فعالیت ها و برنامه های مسجد استقبال می کنند. همچنین نتایج حاصل از تحقیق حاکی از آن است که مساجد برای نیل به جایگاه واقعی خود در جهت ارتقاء میزان اثربخشی در توسعه محله ای، نیازمند برنامه ریزی صحیح و مدیریت هماهنگ، از سوی کلیه مراکز و سازمان هایی است که به نوعی با مساجد در ارتباط هستند. در بخش پایانی این تحقیق، پیشنهادات و راهکارهایی در همین ارتباط، ارائه گردیده است.

It is an undeniable fact that software plays an important role in our lives. We use the software to play our music, to check our e-mail, or even to help us drive our car. Thus, the quality of software directly influences the quality of our lives. However, the traditional Software Engineering paradigm is not able to cope with the increasing demands in quantity and quality of produced software. Thus, a new paradigm of Model Driven Software Engineering (MDSE) is quickly gaining ground. MDSE promises to solve some of the problems of traditional Software Engineering (SE) by raising the level of abstraction. Thus, MDSE proposes the use of models and model transformations, instead of textual program files used in traditional SE, as means of producing software. The models are usually graph-based, and are built by using graphical notations – i.e. the models are represented diagrammatically. The advantages of using graphical models over text files are numerous, for example it is usually easier to deduce the relations between different model elements in their diagrammatic form, thus reducing the possibility of defects during the production of the software. Furthermore, formal model transformations can be used to produce different kinds of artifacts from models in all stages of software production. For example, artifacts that can be used as input for model checkers or simulation tools can be produced. This enables the checking or simulation of software products in the early phases of development, which further reduces the probability of defects in the final software product. However, methods and techniques to support MDSE are still not mature enough. In particular methods and techniques for model configuration management (MCM) are still in development, and no generic MCM system exists. In this thesis, I describe my research which was focused on developing methods and techniques to support generic model configuration management. In particular, during my research, I focused on developing methods and techniques for supporting model evolution and model co-evolution. Described methods and techniques are generic and are suitable for a state-based approach to model configuration management. In order to support the model evolution, I developed methods for the representation, calculation, and visualization of state-based model differences. Unlike in previously published research, where these three aspects of model differences are dealt with in separation, in my research all these three aspects are integrated. Thus, the result of model differences calculation algorithm is in the format which is described by my research on model differences representation. The same representation format of model differences is used as a basis of my approach to differences visualization. It is important to notice that the developed representation format for model differences is metamodel independent, and thus is generic, i.e., it can be used to represent differences between all graph-based models. Model co-evolution is a term that describes the problem of adapting models when their metamodels evolve. My solution to this problem has three steps. In the first step a special metamodel MMfMM is introduced. Unlike in traditional approaches, where metamodels are represented as instances of a metametamodel, in my approach the metamodels are represented by models which are instances of an MMfMM. In the second step, since metamodels are represented by models, previously defined methods and techniques for model evolution are reused to represent and calculate the metamodel differences. In the final step I define an algorithm that uses the calculated metamodel differences to adapt models conforming to the evolved metamodel. In order to validate my approaches to model evolution and model co-evolution, I have developed a tool for comparing models and visualizing resulting differences, and a tool for model co-evolution. Moreover, I have developed a method to compare tools for model comparison, and using this method I have conducted a series of experiments in which I compared the tool I developed to an industrial tool called EMFCompare. The results of these experiments are also presented in the thesis. Furthermore, in order to validate my tool and approach to model co-evolution, I have also specified and conducted several experiments. The results of these experiments are also presented in the thesis.

The development of qualitatively new approaches of training and the creation of an effective education system having a direct impact on the development of engineering science and innovation processes in the and the integration of national research on the world market. To assess the existing problems of improving the quality of training of competent technical staff in the universities of Kazakhstan have been used such methods as empirical research, analysis of engineering and production problems in these sphere . The solution of tasks aimed at improving the training of the modern nation of competent engineers in the technical colleges, whose implementation is possible a deeper theoretical understanding of the national mentality.

Assessing small failure probabilities by AK–SS: An active learning method combining Kriging and Subset Simulation

The optimal controller design framework for PID-based vibration active control systems via non-probabilistic time-dependent reliability measure

The engineering profession in the West African sub-region is not much different from what it is in developed countries all over the world. The relatively under-developed environment has hampered the maximum utilization of the indigenous engineers, The engineering profession in this region has developed from the free-for-all era of the 1960s to a stage in which it is now regally regulated. There is now an accepted code of conduct for all professional engineers. The professional engineering societies ensure that high standards of professional practice and ethics are maintained, and that the engineering profession meets the needs of the West African region. The era when non-registered engineers held posts which discharge and purport to discharge functions which are properly those of registered engineers is rapidly being phased out.