Periodicals of Engineering and Natural Sciences (PEN - International University of Sarajevo)
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The behavior of tapered one-way continuous two-span reinforced concrete slabs under repeated load
Get PDFThe scope of this study is to look at the effect of supplying a non-prismatic cross-section on the flexural strength of one-way continuous slabs reinforced concrete (RC) with two spans under repeated load. The research aims to study the ability of non-prismatic slabs to increase flexural stiffness which leads to saving construction costs. For this purpose, experimental investigations were carried out; the work consisted of fabrication and testing six two-span RC slabs with the same volume of concrete. Two of them were prismatic with a constant depth, while all the others were non-prismatic with tapered cross-sections having varying depth. Prismatic slabs were stiffer than non-prismatic slabs in all support settings, according to the findings. It is found that providing a tapered slab with a positive or a negative haunch has an insignificant effect on the bearing capacity for a prismatic slab. On the other hand, the tapered slab led to increase the deflection at service load compared to the prismatic slab
Using metaheuristics to improve the placement of multi-controllers in software-defined networking enabled clouds
Get PDFSDN is a model that separates the control and the data levels in an arrangement to enhance capability to program and configure the network in a more agile and efficient manner. Multiple controller modules have been used in the SDN engineering to empower programmable and adaptable configurations such as improving scalability and reliability. The distance and time calculations and other performance measures have to be considered in solving the Multi-Controller Position Problem (MCPP). This paper investigates the use of metaheuristic algorithms to build an MCPP mathematical model. Both the symmetric Harmony Search (HS) modelling and the Particle Swarm Optimization (PSO) algorithm are considered in this respect. Thus, our hybrid approach is proposed and known as Harmony Search with Particle Swarm Optimization (HSPSO) is applied and we compared the extracted results with the state-of-the-art techniques in the previous literature. Besides the development of the mathematical model, a simulation study has been done considering the relevant parameters including the link distance description and the access time between the SDN entities. The console simulation uses NetBeans with CloudsimSDN procedure files in the SDN-based cloud environment
The determinants of Germany’s outward foreign direct investment (OFDI)
Get PDFThe aim of this study is to investigate the determinants of Germany\u27s OFDI in the last 21 years on the set of top ten Germany’s OFDI destination (United States of America, United Kingdom, China, France, Poland, Mexico, India, Turkey, Spain and Russia (Russian Federation)) by using panel data analysis. The research revealed that Germany’s OFDI are driven by market seeking motives (FDI vertical), and also highlighting the importance of the stable political environment, attractive tax environment, more trade openness, and stable macroeconomic environment of the top ten Germany’s partners for attractiveness of the Germany’s OFDI. It indicates that openness of an economy is statistically significant in attracting FDI
Preserved built heritage assessment as dead or living: An assessment study regarding built heritage safeguarding approaches in Erbil
Get PDFErbil city is recognized by its historical monuments. The citadel which is believed to be one of the oldest continuously inhabited civilized settlements was listed on UNESCO’s permanent World Heritage List (2014). A comprehensive preservation plan for the citadel was approved by the local authorities in 2006. This plan included recommendations for what was later called the Citadel\u27s buffer zones. The buffer zone includes the traditional sectors of Erbil. Enormous efforts were done during the last decade by local authorities, UNESCO, NGOs, and local individuals. This study aims to assess and categorize preservation efforts implemented in these areas. The literature review diagnosed three main approaches for preservation that are followed in various parts of the world. These approaches can be categorized into two main approaches (dead and living heritage approaches). The preservation methods followed in the selected maintained structures within Erbil\u27s traditional sectors were assessed by detecting 40 criteria that represent both approaches. The assessment was conducted through fieldwork in which 222 samples (vernacular and traditional buildings) were included. Statistical analysis depicted that the local authorities\u27 approaches can be regarded as a dead heritage approach, while the recommended approach in the approved plan for the revitalization of Erbil Citadel and other traditional sectors can be regarded as a living heritage preservation approach. The paper recommends the living heritage preservation approach as a rescue from the at-risk status of built heritage structures of traditional sectors in Erbil city
Deformation behavior of flexible pavements by finite element simulation
Get PDFFlexible pavement is usually designed based on certain axle load limits and climatic conditions. The Iraqi code has specified certain load limits per each axle type that should not be exceeded. However, many trucks violate these limits by carrying additional weights to decrease the transportation cost. These overweight trucks cause severe deterioration to the pavement and thus reduce its life. The Iraqi authorities generally charges the violating trucks a penalty based on their weights. This penalty could be very small compared to the damage occurring to the pavement based on these over weights. Also, some trucks may carry huge weights that the pavement may not support, so unloading such trucks could be a suitable solution rather than paying few amounts of money and deteriorating the pavement. The study aims at studying the effect of axle load increase, and the variation in pavement moduli, on the overall pavement life. It also aims to estimate the overweight truck limits that could be penalized or unloaded. The research uses the ABAQUS software conditions to estimate the tensile strains occurring under the asphalt concrete (AC) layer and the compressive strains above the subgrade surface. These computed strains are incorporated in the fatigue cracking and rutting models to estimate the pavement life for different axle weights. Results showed that violating trucks should be unloaded when their weights exceed certain limits
Seismic evaluation and strengthening of reinforced concrete buildings
Get PDFOne of the best ways of achieving sustainability is to prolong the life span of existing structures instead of the “demolish and rebuild” option. Structure rehabilitation reduces construction waste, conserves natural resources, reduces negative environmental consequences, saves time, and saves cost, etc. Two main categories can be noticed in rehabilitation: repairing and strengthening. This study will focus on the strengthening category. The seismic analysis of existing reinforced concrete buildings before and after strengthening their columns is considered in this study. Three strengthening techniques (Ferro-cement jacket, steel jacket and Carbon fiber reinforced polymer jacket) are used to strengthen the reinforced concrete columns. The building is considered to be subjected to El Centro earthquake in two horizontal directions. The main objective is to investigate the optimum number and locations of the columns required to be strengthened so that the strengthened building satisfies the performance level. Four states of the building are considered; the original building and three strengthened buildings. The strengthening of a part of column height (only one meter along the potential plastic hinge) is considered. The results show that all three strengthening techniques are efficient to resist the seismic loads. This study helps engineers to select suitable, feasible and efficient strengthening techniques for structural members in existing buildings
Assessment the performance of water treatment plants in Baghdad governorate using GIS
Get PDFWater is essential to a solid society and feasible growth. Water demand is increasing due to increasing population density, fast urbanization, industrialization, and agriculture. The Tigris River supplies drinking water to nine water treatment plants in Baghdad, therefore monitoring their chemical and physical properties is important. 15 parameters (pH, Tur., TDS, EC, TH, Alk., Ca+2, Mg+2, Fe+2, Cl-, SO4-2, NH3, NO3-, NO2-, PO43) from treated water were measured in 2009 and 2019 and compared their values to Iraqi and WHO findings. The results show The value of turbidity in 2009 at center 8 was 11.2 which is exceeded the allowable limits this is might be absent the coagulation process, as well as the high concentration of the turbidity in the Tigris river at that time, meanwhile the value of alkalinity, was 159.75(mg/l) in 2019 at center 2 . however the remaining results were inside as far as possible
Geometrical profile of cohesive-frictional soil slopes for optimal stability
Get PDFIn this study, finite element method with strength reduction technique is employed to study the stability of slopes with non-straight line profiles comprises three segments. According to this method, the strength parameters are reduced until the slope becomes on the verge of failure. A software called (Optum G2) is used to analyze the geometrical and mechanical parameters. The effect of the geometrical shape of the slope with specific limitations on the factor of safety (FOS) has been investigated to find the corresponding profile configuration that provides maximum stability. The profile (slope face geometry) has been divided into three straight lines (segments) with different lengths. The study involved the soil cohesion (c), angel of internal friction (∅) and the angle of the imaginary straight line linking the slope toe with slope crest (β) called herein slope inclination. The main results showed that using the three segments facing profile can increase the factor of safety (FOS) by up to 15% in comparison with the corresponding slopes of straight-line profile. Design charts has been introduced to be utilized by engineers and practitioners to obtain the geometrical parameters for the optimal profile as well as the expected improvement percentage in factor of safety
Correlation of model quality between predicted proteins and their templates
Get PDFProtein structure prediction is an important process that carries a lot of benefits for various areas of science and industry. Template modeling is the most reliable and most popular method, depending on the solved structures from the Protein Data Bank. An important part of it is template selection, using different methods, which is a challenging task that requires special attention because the proper selection of protein template can lead to a more accurate protein prediction. This study focuses on the relationships between predicted proteins, taken from the Swiss-model repository, and their templates, on a larger scale. Features of predicted proteins are taken into account, including protein length, sequence identity, and sequence coverage. Quality assessment scores are compared and analyzed between the predicted proteins and their templates. Overall, quality assessment scores of predicted proteins show a moderate positive correlation to the sequence identity with the templates. Moreover, based on our data, the level of template quality is noticeably correlated with the predicted protein structuers, because templates with higher quality scores will, on average, also allow for the modeling of predicted proteins with higher quality scores
Effect of aging time on microstructural and mechanical properties of 6061 aluminum alloy
Get PDFAluminum alloy 6061 have moderate strength, good formability, and excellent corrosion resistance, it has a wide use in several engineering sectors. Age hardening is the main feature of this alloy. In this study, some mechanical characteristics of Aluminum 6061 samples aged to different times has been studied. The specimen’s mechanical properties were improved in general; best mechanical properties were achieved after 2 hours of heat treatment at 200oC. Ultimate tensile stress, yield stress, ductility and microhardness variation with aging time are discussed regarding to the microstructural alteration caused by heat treatment. We found that the Mg2Si initiation and growth was a function for aging time, which was the main cause for improvement of the alloy mechanical features