Search results for: horizontal deflection

Authors: Abdulsamee Halahla, Emad Allout

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The purpose of this research is to study the behavior of exterior beam-column joints (BCJs) strengthened with ultra-high performance concrete (UHPC), in terms of the shear strength and maximum displacement using pushover analysis at the tip of the beam. A finite element (F.E) analysis was performed to study three main parameters – the level of the axial load in the column (N), the beam shear reinforcement (Av/s)B, and the effect of using UHPC. The normal concrete at the studied joint region was replaced by UHPC. The model was verified by using experimental results taken from the literature. The results showed that the UHPC contributed to the transference of the plastic hinge from the joint to the beam-column interface. In addition, the strength of the UHPC-strengthened joints was enhanced dramatically from 8% to 38% for the joints subjected to 12.8MPa and zero axial loads, respectively. Moreover, the UHPC contributed in improving the maximum deflection. This improvement amounted to 1% and 176% for the joints subjected to zero and 12.8MPa axial load, respectively.

Keywords: ultra high performance concrete, ductility, reinforced concrete joints, finite element modeling, nonlinear behavior; pushover analysis

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Authors: A. Ja, J. Belabid, A. Cheddadi

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This paper reports the numerical simulation of double diffusive natural convection flows within a horizontal annular filled with a saturated porous medium. The analysis concerns the influence of the different parameters governing the problem, namely, the Rayleigh number Ra, the Lewis number Le and the buoyancy ratio N, on the heat and mass transfer and on the flow structure, in the case of a fixed radius ratio R = 2. The numerical model used for the discretization of the dimensionless equations governing the problem is based on the finite difference method, using the ADI scheme. The study is focused on steady-state solutions in the cooperation situation.

Keywords: natural convection, double-diffusion, porous medium, annular geometry, finite differences

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Authors: Edna T. Bernabe, Joshua Bilolo, Sheila Mae Artillero, Catlicia Joy Caseda, Liezel Once, Donne Ynah Grace Quirante

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Internal communication is significant for an organization to function to its full extent. A strategic communication plan builds an organization’s structure and makes it more systematic. Information is a vital part of communication inside the organization as this lays every possible outcome—be it positive or negative. It is, therefore, imperative to assess the communication structure of a particular organization to secure a better and harmonious communication environment in any organization. Thus, this research was intended to identify the internal communication channels used in Polytechnic University of the Philippines-College of Communication (PUP-COC) as an organization, to identify the flow of information specifically in downward, upward, and horizontal communication, to assess the accuracy, consistency, and timeliness of its internal communication channels; and to come up with a proposed strategic communication plan of information dissemination to improve the existing communication flow in the college. The researchers formulated a framework from Input-Throughout-Output-Feedback-Goal of General System Theory and gathered data to assess the PUP-COC’s internal communication. The communication model links the objectives of the study to know the internal organization of the college. The qualitative approach and case study as the tradition of inquiry were used to gather deeper understanding of the internal organizational communication in PUP-COC, using Interview, as the primary methods for the study. This was supported with a quantitative data which were gathered through survey from the students of the college. The researchers interviewed 17 participants: the College dean, the 4 chairpersons of the college departments, the 11 faculty members and staff, and the acting Student Council president. An interview guide and a standardized questionnaire were formulated as instruments to generate the data. After a thorough analysis of the study, it was found out that two-way communication flow exists in PUP-COC. The type of communication channel the internal stakeholders use varies as to whom a particular person is communicating with. The members of the PUP-COC community also use different types of communication channels depending on the flow of communication being used. Moreover, the most common types of internal communication are the letters and memoranda for downward communication, while letters, text messages, and interpersonal communication are often used in upward communication. Various forms of social media have been found out to be of use in horizontal communication. Accuracy, consistency, and timeliness play a significant role in information dissemination within the college. However, some problems have also been found out in the communication system. The most common problem are the delay in the dissemination of memoranda and letters and the uneven distribution of information and instruction to faculty, staff, and students. This has led the researchers to formulate a strategic communication plan which aims to propose strategies that will solve the communication problems that are being experienced by the internal stakeholders.

Keywords: communication plan, downward communication, internal communication, upward communication

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Authors: Laura Canagueral-Pellice, Antonio Munar-Frau, Adaia Valls-Ontanon, Joao Carames, Federico Hernandez-Alfaro, Jordi Caballe-Serrano

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Objective: Guided bone regeneration (GBR) aims to replace the missing bone with a new structure to achieve long-term stability of rehabilitations. The aim of the present systematic review and meta-analysis is to determine the effect of barrier membranes on histological outcomes after GBR procedures. Moreover, the effect of the grafting material and tissue gain were analyzed. Materials & methods: Two independent reviewers performed an electronic search in Pubmed and Scopus, identifying all eligible publications up to March 2020. Only randomized controlled trials (RCTs) assessing a histological analysis of augmented areas were included. Results: A total of 6 publications were included for the present systematic review. A total of 110 biopsied sites were analysed; 10 corresponded to vertical bone augmentation procedures, whereas 100 analysed horizontal regeneration procedures. A mean tissue gain of 3 ± 1.48mm was obtained for horizontal defects. Histological assessment of new bone formation, residual particle and sub-epithelial connective tissue (SCT) was reported. The four main barrier membranes used were natural collagen membranes, e-PTFE, polylactic resorbable membranes and acellular dermal matrix membranes (AMDG). The analysis demonstrated that resorbable membranes result in higher values of new bone formation and lower values of residual particles and SCT. Xenograft resulted in lower new bone formation compared to allograft; however, no statistically significant differences were observed regarding residual particle and SCT. Overall, regeneration procedures adding autogenous bone, plasma derivate or growth factors achieved in general greater new bone formation and tissue gain. Conclusions: There is limited evidence favoring the effect of a certain type of barrier membrane in GBR. Data needs to be evaluated carefully; however, resorbable membranes are correlated with greater new bone formation values, especially when combined with allograft materials and/or the addition of autogenous bone, platelet reach plasma (PRP) or growth factors in the regeneration area. More studies assessing the histological outcomes of different GBR protocols and procedures testing different biomaterials are needed to maximize the clinical and histological outcomes in bone regeneration science.

Keywords: barrier membrane, graft material, guided bone regeneration, implant surgery, histology

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Authors: N. F. M. Mokhtar, N. Z. A. Hamid

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This paper reports an analytical investigation of the stability and thermal convection in a horizontal anisotropic porous medium in the presence of Coriolis force and magnetic field. The Darcy model is used in the momentum equation and Boussinesq approximation is considered for the density variation of the porous medium. The upper and lower boundaries of the porous medium are assumed to be conducting to temperature perturbation and we used first order Chebyshev polynomial Tau method to solve the resulting eigenvalue problem. Analytical solution is obtained for the case of stationary convection. It is found that the porous layer system becomes unstable when the mechanical anisotropy parameter elevated and increasing the Coriolis force and magnetic field help to stabilize the anisotropy porous medium.

Keywords: anisotropic, Chebyshev tau method, Coriolis force, Magnetic field

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Authors: Seyed Amin Vakili, Sahar Sadat Vakili, Seyed Ehsan Vakili, Nader Abdoli Yazdi

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The main purpose of this paper is to present the Modified Newmark Method as a method of non-linear frame analysis by considering the effect of the axial load (second order analysis). The discussion will be restricted to plane frameworks containing a constant cross-section for each element. In addition, it is assumed that the frames are prevented from out-of-plane deflection. This part of the investigation is performed to generalize the established method for the assemblage structures such as frameworks. As explained, the governing differential equations are non-linear and cannot be formulated easily due to unknown axial load of the struts in the frame. By the assumption of constant axial load, the governing equations are changed to linear ones in most methods. Since the modeling and the solutions of the non-linear form of the governing equations are cumbersome, the linear form of the equations would be used in the established method. However, according to the ability of the method to reconsider the minor omitted parameters in modeling during the solution procedure, the axial load in the elements at each stage of the iteration can be computed and applied in the next stage. Therefore, the ability of the method to present an accurate approach to the solutions of non-linear equations will be demonstrated again in this paper.

Keywords: nonlinear, stability, buckling, modified newmark method

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Authors: Khaled Sandjak, Boualem Tiliouine

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Structural analysis of flexible pavements has been and still is currently performed using multi-layer elastic theory. However, for thinly surfaced pavements subjected to low to medium volumes of traffics, the importance of non-linear stress-strain behaviour of unbound granular materials (UGM) requires the use of more sophisticated numerical models for structural design and performance of such pavements. In the present work, nonlinear unbound aggregates constitutive model is implemented within an axisymmetric finite element code developed to simulate the nonlinear behaviour of pavement structures including two local aggregates of different mineralogical nature, typically used in Algerian pavements. The performance of the mechanical model is examined about its capability of representing adequately, under various conditions, the granular material non-linearity in pavement analysis. In addition, deflection data collected by falling weight deflectometer (FWD) are incorporated into the analysis in order to assess the sensitivity of critical pavement design criteria and pavement design life to the constitutive model. Finally, conclusions of engineering significance are formulated.

Keywords: FWD backcalculations, finite element simulations, Nonlinear resilient behaviour, pavement response and performance, RLT test results, unbound granular materials

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Authors: Noureddine Ben Ayed, Abdelkader Soumaya, Saïd Maouche, Ali Kadri, Mongi Gueddiche, Hayet Khayati-Ammar, Ahmed Braham

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The archaeological monument of Utica, located in north-eastern Tunisia, was founded (8th century BC) By the Phoenicians as a port installed on the trade route connecting Phoenicia and the Straits of Gibraltar in the Mediterranean Sea. The flourishment of this city as an important settlement during the Roman period was followed by a sudden abandonment, disuse and progressive oblivion in the first half of the fifth century AD. This decadence can be attributed to the destructive earthquake of 5 July 408 - 410 AD, affecting this historic city as documented in 1906 by the seismologist Fernand De Montessus De Ballore. The magnitude of the Utica earthquake was estimated at 6.8 by the Tunisian National Institute of Meteorology (INM). In order to highlight the damage caused by this earthquake, a field survey was carried out at the Utica ruins to detect and analyse the earthquake archaeological effects (EAEs) using structural geology methods. This approach allowed us to highlight several structural damages, including: (1) folded mortar pavements, (2) cracks affecting the mosaic and walls of a water basin in the "House of the Grand Oecus", (3) displaced columns, (4) block extrusion in masonry walls, (5) undulations in mosaic pavements, (6) tilted walls. The structural analysis of these EAEs and data measurements reveal a seismic cause for all evidence of deformation in the Utica monument. The maximum horizontal strain of the ground (e.g. SHmax) inferred from the building oriented damage in Utica shows a NNW-SSE direction under a compressive tectonic regime. For the seismogenic source of this earthquake, we propose the active E-W to NE-SW trending Utique - Ghar El Melh reverse fault, passing through the Utica Monument and extending towards the Ghar El Melh Lake, as the causative tectonic structure. The active fault trace is well supported by instrumental seismicity, geophysical data (e.g., gravity, seismic profiles) and geomorphological analyses. In summary, we find that the archaeoseismic records detected at Utica are similar to those observed at many other archaeological sites affected by destructive ancient earthquakes around the world. Furthermore, the calculated orientation of the average maximum horizontal stress (SHmax) closely match the state of the actual stress field, as highlighted by some earthquake focal mechanisms in this region.

Keywords: Tunisia, utica, seimogenic fault, archaeological earthquake effects

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Authors: Yuan Zhang

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Along with large population and great demands for urban development, Hong Kong serves as a typical high-density city with multiple altitudes, advanced three-dimensional traffic system, rich city open space, etc. This paper contributes to analyzing its complex urban form and evolution mechanism from three aspects of view, separately as time, space and buildings. Taking both horizontal and vertical dimension into consideration, this paper provides a perspective to explore the fascinating process of growing and space folding in the urban form of high-density city, also as a research reference for related high-density urban design.

Keywords: evolution mechanism, high-density city, Hong Kong, urban form

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Authors: Kious Mecheri, Hadjadj Abdechafik, Ameur Aissa

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The wear of cutting tool degrades the quality of the product in the manufacturing processes. The online monitoring of the cutting tool wear level is very necessary to prevent the deterioration of the quality of machining. Unfortunately there is not a direct manner to measure the cutting tool wear online. Consequently we must adopt an indirect method where wear will be estimated from the measurement of one or more physical parameters appearing during the machining process such as the cutting force, the vibrations, or the acoustic emission etc. In this work, a neural network system is elaborated in order to estimate the flank wear from the cutting force measurement and the cutting conditions.

Keywords: flank wear, cutting forces, high speed milling, signal processing, neural network

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Authors: Wen-Yuh Jywe, Bor-Jeng Lin, Jing-Chung Shen, Jeng-Dao Lee, Hsueh-Liang Huang, Tung-Hsien Hsieh

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In this study, a simple 2-D measurement system based on optical design was developed to measure the motion errors of the linear guideway. Compared with the transitional methods about the linear guideway for measuring the motion errors, our proposed 2-D optical measurement system can simultaneously measure horizontal and vertical running straightness errors for the linear guideway. The performance of the 2-D optical measurement system is verified by experimental results. The standard deviation of the 2-D optical measurement system is about 0.4 μm in the measurement range of 100 mm. The maximum measuring speed of the proposed automatic measurement instrument is 1 m/sec.

Keywords: 2-D measurement, linear guideway, motion errors, running straightness

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Authors: M. Al-Farttoosi, M. Y. Rafiq, J. Summerscales, C. Williams

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Structures can be subjected to impact loading from various sources like earthquake, tsunami, missiles and explosions. The impact loading can cause different degrees of damage to concrete structures. The demand for strengthening and rehabilitation of damaged structures is increasing. In recent years, Car0bon Fibre Reinforced Polymer (CFRP) matrix composites has gain more attention for strengthening and repairing these structures. To study the impact behaviour of the reinforced concrete (RC) beams strengthened or repaired using CFRP, a heavy impact test machine was designed and manufactured .The machine included a newly designed support system for beams together with various instrumentation. This paper describes the support design configuration of the impact test machine, instrumentation and dynamic analysis of the concrete beams. To evaluate the efficiency of the new impact test machine, experimental impact tests were conducted on simple supported reinforced concrete beam. Different methods were used to determine the impact force and impact response of the RC beams in terms of inertia force, maximum deflection, reaction force and fracture energy. The manufactured impact test machine was successfully used in testing RC beams under impact loading and used successfully to test the reinforced concrete beams strengthened or repaired using CFRP under impact loading.

Keywords: beam, concrete, impact, machine

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Authors: Yeong-cheng Wang, Jin-Yinn Wang, Ming-Shan Lin, Jian-Li Dong

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To universalize the adoption of sustainable energy, the R.O.C. government encourages public buildings to introduce the PV power station on the building roof, whereas most old buildings did not include the considerations of photovoltaic (PV) power facilities in the design phase. Several factors affect the PV electricity output, the temperature is the key one, different PV technologies have different temperature coefficients. Other factors like PV panel azimuth, panel inclination from the horizontal plane, and row to row distance of PV arrays, mix up at the beginning of system design. The goal of this work is to maximize the annual energy output of a roof mount PV system. Tables to simplify the design work are developed; the results can be used for engineering project quote directly.

Keywords: optimal inclination, array azimuth, annual output

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Authors: Mezidi Amar

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In this research work, crack propagation at the interface of a composite beam is considered. The behavior of composite beams (CB) depends upon a law based on relationship between tangential or normal efforts with inelastic propagation. Throughout this study, composite beams are classified like composite beams with partial connection or sandwich beams of three layers. These structural systems are controlled by the same nature of differential equations regarding their behavior in the plane, as well as out-of-plane. Multi-layer elements with partial connection are typically met in the field of timber construction where the elements are assembled by joining. The formalism of the behavior in the plane and out-of-plane of these composite beams is obtained and their results concerning the engineering aspect or simple of interpretation are proposed for the case of composite beams made up of rectangular section and simply supported section. An apparent analytical peculiarity or paradox in the bending behavior of elastic–composite beams with interlayer slip, sandwich beam or other similar problems subjected to boundary moments exists. For a fully composite beam subjected to end moments, the partial composite model will render a non-vanishing uniform value for the normal force in the individual subelement. Obtained results are similar to those for the case of vibrations in the plane as well for the composite beams as for the sandwich beams where eigen-frequencies increase with related rigidity.

Keywords: composite beam, behaviour, interface, deflection, propagation

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Authors: T. Karech A. Noui, T. Bouzid

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This article presents a comparative study by numerical analysis of the behavior of reinforcements of clayey soils by flexible columns (stone columns) and rigid columns (piles). The numerical simulation was carried out in 3D for an assembly of foundation, columns and a pile of a bridge. Particular attention has been paid to take into account the installation of the columns. Indeed, in practice, due to the compaction of the column, the soil around it sustains a lateral expansion and the horizontal stresses are increased. This lateral expansion of the column can be simulated numerically. This work represents a comparative study of the interaction between the soil on one side, and the two types of reinforcement on the other side, and their influence on the behavior of the soil and of the pile of a bridge.

Keywords: piles, stone columns, interaction, foundation, settlement, consolidation

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Authors: András Szekrényes

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Delamination is one of the major failure modes in laminated composite structures. Delamination tips are mostly captured by spatial numerical models in order to predict crack growth. This paper presents some mechanical models of delaminated composite shells based on shallow shell theories. The mechanical fields are based on a third-order displacement field in terms of the through-thickness coordinate of the laminated shell. The undelaminated and delaminated parts are captured by separate models and the continuity and boundary conditions are also formulated in a general way providing a large size boundary value problem. The system of differential equations is solved by the state space method for an elliptic delaminated shell having simply supported edges. The comparison of the proposed and a numerical model indicates that the primary indicator of the model is the deflection, the secondary is the widthwise distribution of the energy release rate. The model is promising and suitable to determine accurately the J-integral distribution along the delamination front. Based on the proposed model it is also possible to develop finite elements which are able to replace the computationally expensive spatial models of delaminated structures.

Keywords: J-integral, levy method, third-order shell theory, state space solution

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Authors: Chung-Hao Wu, Tung-Dju Lin, Ming-Chin Ho, Minehiro Nishiyama

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This paper discusses reported fire tests of concrete beams and columns, future fire tests of beam/column frames, and an innovative concept for designing a beam/column furnace. The proposed furnace could be designed to maximize the efficiency of fire test procedures and minimize the cost of furnace construction and fuel consumption. ASTM E119 and ISO 834 standards were drafted based on prescriptive codes and have several weaknesses. The first involves a provision allowing the support regions of a test element to be protected from fire exposure. The second deals with the L/30 deflection end point instead of the structural end point (collapse) in order to protect the hydraulic rams from fire damage. Furthermore, designers commonly use the measured fire endurances of interior columns to assess fire ratings of edge and corner columns of the same building. The validity of such an engineering practice is theoretically unsound. Performance-Based Codes (PBC) require verification tests of structural frames including the beam/column joints to overcome these weaknesses but allow the use of element test data as reference only. In the last 30 years, PBC have gained global popularity because the innovative design and flexibility in achieving an ultimate performance goal.

Keywords: fire resistance, concrete structure, beam/column frame, fire tests

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Authors: S. A. Tabatabaei, S. Aarabi

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Predicting the hot mix asphalt (HMA) response and performance is a challenging task because of the subjectivity of HMA under the complex loading and environmental condition. The behavior of HMA is a function of temperature of loading and also shows the time and rate-dependent behavior directly affecting design criteria of mixture. Velocity of load passing make the time and rate. The viscoelasticity illustrates the reaction of HMA under loading and environmental conditions such as temperature and moisture effect. The behavior has direct effect on design criteria such as tensional strain and vertical deflection. In this paper, the computational framework for viscoelasticity and implementation in 3D dimensional HMA model is introduced to use in finite element method. The model was lied under various repeated loading conditions at constant temperature. The response of HMA viscoelastic behavior is investigated in loading condition under speed vehicle and sensitivity of behavior to the range of speed and compared to HMA which is supposed to have elastic behavior as in conventional design methods. The results show the importance of loading time pulse, unloading time and various speeds on design criteria. Also the importance of memory fading of material to storing the strain and stress due to repeated loading was shown. The model was simulated by ABAQUS finite element package

Keywords: viscoelasticity, finite element method, repeated loading, HMA

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Authors: G. A. Florides, E. Theofanous, I. Iosif-Stylianou, P. Christodoulides, S. Kalogirou, V. Messarites, Z. Zomeni, E. Tsiolakis, P. D. Pouloupatis, G. P. Panayiotou

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Ground Coupled Heat Pumps (GCHPs) exploit effectively the heat capacity of the ground, with the use of Ground Heat Exchangers (GHE). Depending on the mode of operation of the GCHPs, GHEs dissipate or absorb heat from the ground. For sizing the GHE the thermal properties of the ground need to be known. This paper gives information about the density, thermal conductivity, specific heat and thermal diffusivity of various lithologies encountered in Cyprus with various relations between these properties being examined through comparison and modeling. The results show that the most important correlation is the one encountered between thermal conductivity and thermal diffusivity with both properties showing similar response to the inlet and outlet flow temperature of vertical and horizontal heat exchangers.

Keywords: ground heat exchangers, ground thermal conductivity, ground thermal diffusivity, ground thermal properties

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Authors: Lina Khashogji

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This study highlights on analysing the educational experience of female Saudi Arabian students in private schools in Islamic studies subjects. Exploring how school environment, teachers’ authority and textbooks could influence the level of individuality. Considering the complex interaction between religious is social and political power in Saudi Arabia. The study draws on phenomenology as a guiding theoretical framework using multi methods. It includes a vertical/horizontal individualism measurement tool “survey” used on 120 students of two age groups (9-12) and (13-15). Semi-structured interviews with eight school teachers, observational notes in the classroom, and textbook analysis. The study links the interactions between the student mind, the teacher, the classroom and the curriculum.

Keywords: education, individualism, identity development, Islamic studies, Saudi Arabia

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Authors: Jamal A. Gledan, Othman A. Azzeidani

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During the last decade, Libya established a new Geodetic Datum called Libyan Geodetic Datum 2006 (LGD 2006) by using GPS, whereas the ground traversing method was used to establish the last Libyan datum which was called the Europe Libyan Datum 79 (ELD79). The current research paper introduces ELD79 to LGD2006 coordinate transformation technique, the accurate comparison of transformation between multiple regression equations and the three-parameters model (Bursa-Wolf). The results had been obtained show that the overall accuracy of stepwise multi regression equations is better than that can be determined by using Bursa-Wolf transformation model.

Keywords: geodetic datum, horizontal control points, traditional similarity transformation model, unconventional transformation techniques

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Authors: O. W. Lawal, L. O. Ahmed, Y. K. Ali

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The unsteady MHD Poiseuille flow of a third grade fluid between two parallel horizontal nonconducting porous plates is studied with heat transfer. The two plates are fixed but maintained at different constant temperature with the Joule and viscous dissipation taken into consideration. The fluid motion is produced by a sudden uniform exponential decaying pressure gradient and external uniform magnetic field that is perpendicular to the plates. The momentum and energy equations governing the flow are solved numerically using Maple program. The effects of magnetic field and third grade fluid parameters on velocity and temperature profile are examined through several graphs.

Keywords: exponential decaying pressure gradient, MHD flow, Poiseuille flow, third grade fluid

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Authors: Mengqi Zhu, Chang Nyung Kim

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This study numerically investigates three-dimensional liquid-metal (LM) magnetohydrodynamic (MHD) flows in a misaligned duct under a uniform magnetic field. The duct consists of two misaligned horizontal channels (one is inflow channel, the other is outflow channel) and one central vertical channel. Computational fluid dynamics simulations are performed to predict the behavior of the MHD flows, using commercial code CFX. In the current study, a case with Hartmann number 1000 is considered. The electromagnetic features of LM MHD flows are elucidated to examine the interdependency of the flow velocity, current density, electric potential, pressure drop and Lorentz force. The results show that pressure decreases linearly along the main flow direction.

Keywords: CFX, liquid-metal magnetohydrodynamic flows, misaligned duct, pressure drop

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Authors: Debjit Ray

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Horizontal gene transfer (HGT) and recombination leads to the emergence of bacterial antibiotic resistance and pathogenic traits. HGT events can be identified by comparing a large number of fully sequenced genomes across a species or genus, define the phylogenetic range of HGT, and find potential sources of new resistance genes. In-depth comparative phylogenomics can also identify subtle genome or plasmid structural changes or mutations associated with phenotypic changes. Comparative phylogenomics requires that accurately sequenced, complete and properly annotated genomes of the organism. Assembling closed genomes requires additional mate-pair reads or “long read” sequencing data to accompany short-read paired-end data. To bring down the cost and time required of producing assembled genomes and annotating genome features that inform drug resistance and pathogenicity, we are analyzing the performance for genome assembly of data from the Illumina NextSeq, which has faster throughput than the Illumina HiSeq (~1-2 days versus ~1 week), and shorter reads (150bp paired-end versus 300bp paired end) but higher capacity (150-400M reads per run versus ~5-15M) compared to the Illumina MiSeq. Bioinformatics improvements are also needed to make rapid, routine production of complete genomes a reality. Modern assemblers such as SPAdes 3.6.0 running on a standard Linux blade are capable in a few hours of converting mixes of reads from different library preps into high-quality assemblies with only a few gaps. Remaining breaks in scaffolds are generally due to repeats (e.g., rRNA genes) are addressed by our software for gap closure techniques, that avoid custom PCR or targeted sequencing. Our goal is to improve the understanding of emergence of pathogenesis using sequencing, comparative genomics, and machine learning analysis of ~1000 pathogen genomes. Machine learning algorithms will be used to digest the diverse features (change in virulence genes, recombination, horizontal gene transfer, patient diagnostics). Temporal data and evolutionary models can thus determine whether the origin of a particular isolate is likely to have been from the environment (could it have evolved from previous isolates). It can be useful for comparing differences in virulence along or across the tree. More intriguing, it can test whether there is a direction to virulence strength. This would open new avenues in the prediction of uncharacterized clinical bugs and multidrug resistance evolution and pathogen emergence.

Keywords: genomics, pathogens, genome assembly, superbugs

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Authors: M. A. Sadeghian, J. Yang, Q. F. Liu

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Steel extended end plate bolted connections are recommended to be widely utilized in special moment-resisting frame subjected to monotonic loading. Improper design of steel beam to column connection can lead to the collapse and fatality of structures. Therefore comprehensive research studies of beam to column connection design should be carried out. Also the performance and effect of corrugated on the strength of beam column end plate connection up to failure under monotonic loading in horizontal direction is presented in this paper. The non-linear elastic–plastic behavior has been considered through a finite element analysis using the multi-purpose software package LUSAS. The effect of vertically and horizontally types of corrugated web was also investigated.

Keywords: corrugated beam, monotonic loading, finite element analysis, end plate connection

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Authors: M. A. Ahmed, Sidra A. Shaikh, M. W. Akhtar

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Global and Diffuse Solar radiation on horizontal surface over two cities of Sindh, namely Jacobabad and Rohri were carried out using sunshine hour data of the area to assess the feasibility of solar energy utilization in Sindh province. The result obtained shows a high variation in direct and diffuse component of solar radiation in summer and winter months (80% direct and 20% diffuse). The contribution of diffuse solar radiation is low even in monsoon months i.e. July and August. The appearance of cloud is rare even in monsoon months. The estimated value indicates that this part of Sindh has higher solar potential and solar panels can be used for power generation. The solar energy can be utilized throughout the year in this part of Sindh, Pakistan.

Keywords: solar potential over Sindh, global and diffuse solar radiation, radiation over two cities of Sindh, environmental engineering

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Authors: Fereshteh Akbari, Farrokh Jalali Mosalam, Ali Hedayatifar, Amirreza Aminjavaheri

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The soil nailing is an effective method to stabilize slopes and retaining structures. Consequently, the lateral and vertical displacement of retaining walls are important criteria to evaluate the safety risks of adjacent structures. This paper is devoted to the optimization problems of retaining walls based on ABAQOUS Software. The various parameters such as nail length, orientation, arrangement, horizontal spacing, and bond skin friction, on lateral and vertical displacement of retaining walls are investigated. In order to ensure accuracy, the mobilized shear stress acting around the perimeter of the nail-soil interface is also modeled in ABAQOUS software. The observed trend of results is compared to the previous researches.

Keywords: retaining walls, soil nailing, ABAQOUS software, lateral displacement, vertical displacement

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Authors: Aymen H. Khalil, Ashraf M. Heniegal, Bassam A. Abdelsalam

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There are many problems related to cantilever slabs such as the time-dependent deformation, corrosion problems of steel reinforcement, and lack of experimental studies on the strength of strengthened cantilever slabs. This paper presents an investigation to evaluate the behavior of reinforced concrete cantilever slabs after strengthening with different techniques. Six medium scale specimens, divided into three groups, were tested along with a control slab. The first group consists of two specimens which were repaired and strengthened using reinforced concrete jacket above with and without shear connector bars, whereas the second group contained two slabs which were strengthened using two strips of two layers of glass fiber reinforced polymer (GFRP) covering 60% and 90% from the cantilever length. The last group involves two specimens strengthened with two steel plates. In one specimen, the steel plates were glued to the surface using epoxy resin. The second specimen, the steel plates were affixed to the concrete surface using expansion bolts. The loading was conducted in two phases. Firstly, the samples were subjected to 40% of the ultimate load of the control slab. Secondly, the specimens reloaded after being strengthened up to failure. The load-deflection, steel strain, concrete strain, failure mode, toughness, and ductility index are discussed in this paper.

Keywords: repair, strengthened, GFRP layers, reloaded, jacketing, cantilever slabs

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Authors: Babagana Abubakar, Alhaji Kuya

Abstract:

Although the field of Space weather science is a young field among the space sciences, but yet history has it that activities related to this science began since the year 1859 when the great solar storm happened which resulted in the disruptions of telegraphs operations around the World at that particular time subsequently making it possible for the scientist Richard Carrington to be able to connect the Solar flare observed a day earlier before the great storm and the great deflection of the Earth’s Magnetic field (geometric storm) simultaneous with the telegraph disruption. However years later as at today with the advent of and the coming into existence of the Explorer 1, the Luna 1 and the establishments of the United States International Space Weather Program, International Geophysical Year (IGY) as well as the International Center for Space Weather Sciences and Education (ICSWSE) have made us understand the Space weather better and enable us well define the field of Space weather science. Despite the successes recorded in the development of Space sciences as a whole over the last century and the coming onboard of specialized bodies/programs on space weather like the International Space Weather Program and the ICSWSE, the majority of Africans including institutions, research organizations and even some governments are still ignorant about the existence of theSpace weather science,because apart from some very few countries like South Africa, Nigeria and Egypt among some few others the majority of the African nations and their academic institutions have no knowledge or idea about the existence of this field of Space science (Space weather).

Keywords: Africa, space, weather, education, science

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Authors: Abdul Qader Melhem, Hacene Badache

Abstract:

This paper deals with the theoretical and experimental study of shear connection via simple steel reinforcement shear connectors, which are steel reinforcing bars bent into L-shapes, instead of commonly used headed studs. This suggested L-shape connectors are readily available construction material in steel reinforcement. The composite section, therefore, consists of steel inverted T-section being embedded within a lightly reinforced concrete flange at the top slab as a unit. It should be noted that the cross section of these composite models involves steel inverted T-beam, replacing the steel top flange of a standard commonly employed I-beam section. The paper concentrates on the elastic and elastic-plastic behavior of these composite models. Failure modes either by cracking of concrete or shear connection be investigated in details. Elastic and elastoplastic formulas of the composite model have been computed for different locations of NA. Deflection formula has been derived, its value was close to the test value. With a supportive designing curve, this curve is valuable for both designing engineers and researchers. Finally, suggested designing curves and valuable equations will be presented. A check is made between theoretical and experimental outcomes.

Keywords: composite, elastic-plastic, failure, inverted T-section, L-Shape connectors

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