bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative assessment of environmental variables and machine learning algorithms for maize yield prediction in the US Midwest
Authors: Kang Yanghui , Ozdogan Mutlu , Zhu Xiaojin , Ye Zhiwei , Hain Christopher , Anderson Martha 
Published: March 2020

Abstract
Crop yield estimates over large areas are conventionally made using weather observations, but a comprehensive understanding of the effects of various environmental indicators, observation frequency, and the choice of prediction algorithm remains elusive. Here we present a thorough assessment of county-level maize yield prediction in U.S. Midwest using six statistical/machine learning algorithms (Lasso, Support Vector Regressor, Random Forest, XGBoost, Long-short term memory (LSTM), and Convolutional Neural Network (CNN)) and an extensive set of environmental variables derived from satellite observations, weather data, land surface model results, soil maps, and crop progress reports. Results show that seasonal crop yield forecasting benefits from both more advanced algorithms and a large composite of information associated with crop canopy, environmental stress, phenology, and soil properties (i.e. hundreds of features). The XGBoost algorithm outperforms other algorithms both in accuracy and stability, while deep neural networks such as LSTM and CNN are not advantageous. The compositing interval (8-day, 16-day or monthly) of time series variable does not have significant effects on the prediction. Combining the best algorithm and inputs improves the prediction accuracy by 5% when compared to a baseline statistical model (Lasso) using only basic climatic and satellite observations. Reasonable county-level yield foresting is achievable from early June, almost four months prior to harvest. At the national level, early-season (June and July) prediction from the best model outperforms that of the United States Department of Agriculture (USDA) World Agricultural Supply and Demand Estimates (WASDE). This study provides insights into practical crop yield forecasting and the understanding of yield response to climatic and environmental conditions.
State of Building Information Modelling (BIM) adoption in Iraq
Authors: Alsaeedi Firas , Lafta Mouhamed Jessam , Ahmed Abdulazeez 
Published: March 2020

Abstract
Building Information Modelling (BIM) is one of the most promising technologies in the Architecture, Engineering and Construction (AEC) industry. However, while a number of studies have shown the benefits of BIM, especially in infrastructure projects, barriers exist to actualising these benefits through implementation. In Iraq, there is a lack of BIM adoption among construction firms because industry practitioners are not interested in BIM and the firms do not have the adequate experience in this technology. The focus of this study is to investigate the current state of BIM adoption in construction industry in Iraq and determine the barriers that prevent its widespread. The key findings of this study are; first habitual resistance to change has the most adverse effect to BIM implementation in the country, second AutoCAD, STAAD Pro and Revit are the most common BIM tools used by BIM adopters in Iraq and finally the results indicate that BIM adoption is not satisfactory because the majority of respondents had only 3 to 6 years’ experience working with BIM Introduction.
Free vibration of non-prismatic beam on variable Winkler elastic foundations
Authors: Al-Azzawi Adel A , Daud Khalida A 
Published: March 2020

Abstract
In this paper, the finite difference and the finite element methods are applied to evaluate natural frequencies of non-prismatic and non-homogeneous beams, with different boundary conditions and resting on variable Winkler foundation. The finite difference method is used for solving differential equation of motion, especially with variable coefficients. This technique requires a lesser computing effort and is used in situation where the exact solution is very difficult to obtain. The main idea of this method is replacing derivatives present in the free vibration equation and boundary condition equations with finite difference expressions. The natural frequencies are determined by solving the eigenvalue problem of the obtained algebraic system resulting from finite difference method. In order to illustrate the correctness and performance of the method, a comprehensive numerical example of non-prismatic beams is presented. The results are compared with the finite element results using ABAQUS software and other available numerical and analytical solutions.
Influence of steel fibers on the behavior of spirally RC short columns
Authors: Khalel Raid I , Sarsam Kaiss F , Al-Shamma Bilal A 
Published: March 2020

Abstract
This study provides an experimental test to examine the behavior of spirally reinforced short columns with circular sections, strengthened by steel fibers. The volume percentage of steel fibers was (0.5, 1.0, 1.5) %. Four series comprising a total of 16 column specimens (600 mm length × 150 mm diameter) were loaded to failure under axial concentric compression load. The findings of this work are as follows: for the control specimens (columns without steel fibers), the spiral pitch influence was significant: as compared to spiral pitch of 100 mm, reducing the spacing to 75 mm, 50 mm, and 25 mm increased the ultimate load capacity by 7.6%, 11.5% and 18.4%, respectively. The steel fibers effect was very significant in increasing the ultimate load capacity of the columns. For 100 mm spiral pitch columns, these increases reached to 24.6%, 36.3% and 49.9% for the columns with 0.5%, 1.0% and 1.5% steel fibers volume percentages, respectively in comparison to the control specimen. The columns with lesser amount of spirals (less internal confinement) were strengthened by the steel fibers more than the ones with greater number of spirals. For 1.5% steel fibers volume percentage, the column with 100 mm spiral pitch was strengthened by 49.9% with steel fibers. In contrast, the one with 25 mm spiral pitch increased in strength with steel fibers by 41.4%.
Structural Behavior of a Coupled Concrete Dam-Reservoir system under Effect of Earthquake loads Using Concrete Damaged Plasticity Model
Authors: Hasan Qais Abdulmajeed , Al-Wakel Saad Faik Abbas , Jaafar Sadeq Aia 
Published: March 2020

Abstract
In this study the effect of dam-reservoir interaction on the dynamic response of gravity dam by assuming the mass concrete is able to be cracked and crushed in tension and compression, respectively is considered. Where the effect of reservoir fluctuation on the dynamic response of concrete dam is investigated. In this study, to simulate the nonlinear behavior of concrete and specifying the position and direction of cracks which is occurred in gravity dam, the concrete damaged plasticity model is used. The results of this study indicate that, the maximum relative displacement in the downstream direction of a dam subjected to an earthquake is occurred when the height of water in the reservoir is at the middle of the dam. In addition, in the case of water level in the reservoir is at the base of dam, the maximum relative displacement of the dam is at the upstream.
Value Engineering and Constructability Assessment Relating Infrastructure Projects
Authors: Al-Fadhli Suaad Khaleel I. 
Published: March 2020

Abstract
Construction projects, especially infrastructure projects, are considered as the most important interests of countries, due to their direct effects on economy, countries development, and all life’s aspects. Accordingly, many technologies and programs have been developed trying to control projects in terms of costs, time of implementation, and the outputs quality. Among the best practices that have proven successful in this area are constructability and value engineering. In this research infrastructure projects in Iraq were assessed, and found that those projects suffer from failure on several fronts, because they are implemented using traditional methods which lead to a significant waste in resources. A model based on the concepts of constructability and value engineering is proposed and applied to project phases, including the operation & maintenance phases. Results show that applying the suggested model lead to saving time, cost and improving the required quality of materials and work, by taking advantage of experience of all project’s partners involved in the project.
Upgrading of normal concrete service life by using SIFCON layers
Authors: Hameed Dalya H. , Salih Shakir A. , Habeeb Galib M. 
Published: March 2020

Abstract
Slurry infiltrated fibrous concrete (SIFCON) is a form of superior performance fiber reinforced concrete made by penetrating steel fiber bed with an exceptionally designed slurry of cement-based. Researches have demonstrated that SIFCON is an imaginative building material having both extensive ductility and high strength. In the current study, the use of SIFCON has been investigated as a strengthening layer for conventional concrete section. The effects of the SIFCON layer position (bottom, top & bottom, and jacket), thickness (1.5, 2.5, and 3.5) cm, and steel fiber volume fraction (6, 7.5, and 9) % on the flexural strength, toughness, and ductility of hybrid prisms were reported. The results showed that the increase in thickness of the SIFCON layer and the steel fiber volume fraction improves load bearing capacity, toughness, and ductility of the composite sections. The maximum ductility and load carrying capacity achieved from the jacketing case. Also, the toughness enhanced greatly in the case of jacketing composite section, it was 23 times higher than that of control prisms.
The effects of different polymer materials on concrete properties containing superabsorbent polymers (SAP)-experimental study
Authors: Khattab Mustafa M. , Tobeia Sameh Badry , Jessam Lafta Mouhammed 
Published: March 2020

Abstract
The use of admixtures in concrete production has become more common in the last decades due to the promising development in concrete technology. Each one of these admixtures can be used to enhance one or more of concrete properties in the fresh, hardened or both concrete conditions. Superabsorbent Polymers (SAP) is one of the polymer admixtures that is recently used for internal curing by controlling and absorbing water within concrete. This could provide several benefits, most important being, durability of concrete. The aim of this study is to experimentally investigate the effect of different polymeric materials represented by Styrene-Butadiene Rubber (SBR) and Polypropylene Fibers (PF) on the mechanical properties of concrete containing Superabsorbent Polymers (SAP). The results of this study revealed the fact that using SAP in concrete mixes improves durability. Despite this, a notable reduction in compressive strength can be observed. The use of both SAP and PF had an undesirable influence on the strength and workability of concrete. Using SBR in concrete mixes containing SAP assisted in recuperating the hardened splitting tensile strength of concrete.
Studying the effect of waterproofing admixtures on some properties of cement mortar
Authors: Muwashee Rawa Shakir , Al-Jameel Hamid Athab 
Published: March 2020

Abstract
This study mainly focused on testing the feasibility of using some finely divided materials (waterproofing) as a permeability-reducing admixture in mortar after mixing with sulphate resisting cement and fine sand and evaluating the effects of these materials on the other properties of mortar. Bentonite and limestone dust are used as a permeability –reducing admixture. Permeability, compressive strength, modulus of rupture, density and ultrasonic pulse velocity tests have been investigated in this study. At 1% of bentonite addition, the quantity of penetrated water reaches about 91% of the water permeation quantity of the control mix. The results indicate that the optimum percentage of limestone is 2.5% of the cement weight, the quantity of penetrated water through mortar at this level is about 18.2% and 47.8% of the water permeation quantity of the control mix of rich and lean mixes, respectively. The addition of 7.5% of limestone dust in rich mix results in an improvement in compressive strength by about 51.8%. Other mortar properties including modulus of rupture indicates trends similar to that observed in compressive strength for all materials used in this study.
Residual strength and degradation of cement mortar containing polypropylene fibers at elevated temperature
Authors: Alani Safa Saib , Hassan Maan S. , Jaber Ali A. 
Published: March 2020

AbstractThe elevated temperatures caused by fire affect the physical and chemical properties of the mortar and thus, influence its mechanical properties. This study presents the results of an experimental investigation on the mechanical properties and microstructure of cement based mortar composites contained polypropylene (PP) at high temperatures. The mortar was prepared and cured as per the relevant international standards. Upon curing, tested specimens were exposed to 250, 450, 600 and 900 °C for 2 h. The influence of the high temperatures on the physical and chemical changes of the blended cement mortar was also analyzed by Scanning Electron Microscopy. Mortar specimens exposed to different high temperatures were tested for compressive and flexural strengths, and compared with control specimens (i.e. unheated). Results revealed that even low fiber dosage of PP fibers with mortars was helpful in completely preventing explosive spalling due to significant increase of permeability. Mechanical results and microstructural analysis of mortar specimens showed that both compressive and tensile strengths were initially increased at 250C°, followed by considerable reduction at higher temperatures.
Testing and Evaluation of Flowability, Viscosity and Long-Term Compressive Strength of Cement Modified with Polymeric Admixture WR Superplasticizer
Authors: Burhan Lajan , Ghafor Kawan , Mohammed Ahmed 
Published: March 2020

Abstract
In this study, the effect of three types of powder polymer water reducer (WR) superplasticizer on the fluidity, rheological properties, density and mechanical properties of cement were investigated. The behavior of cement paste in the liquid phase and hardened phase modified with polymers up to 0.25% (by dry weight of cement) were studied. The amount of mixing water was reduced and varied between 20% - 58%. The Vipulanandan model was used to predict the water to cement ratio (w/c) of cement. The flowability, compressive strength, and density at different curing times were increased with increasing the polymer content. Three different brand of water reducer (WR) powder polymer increased the apparent viscosity of the cement paste; the viscosity was varied between 135 cP and 652 cP based on the type of polymer, polymer content, temperature, and water to cement ratio (w/c). Using of 0.25% of polymers to the cement increased the compressive strength of the cement paste by 127% to 426% based on the types of polymer, polymer content, and water to cement ratio (w/c) and curing time. Regression analysis was used to evaluate the effect of each polymer contents, w/c and curing time on the compressive strength of cement paste.
Smart textiles for the architectural façade
Authors: Jalil W D Abdul 
Published: March 2020

Abstract
Historically, the availability of new materials inspires designers and architects with new potential solutions. Recently, architectural applications have more concerns about sustainable requirements, which are combined with the development of nanotechnology. The availability of nanomaterials and nano-devices offer the possibility to produce smart textiles. However, smart textiles witness a commercial production and increasing application for the contemporary architectural façades. The availability of nanomaterials adds smartness to the textiles by the use of a coating, like self-healing, antimicrobial, anti-fouling, self-thermos regulating, etc. Other nanomaterials are used like conductive ink, thermos-chromic inks, conductive polymers, conductive threads, shape memory materials, piezoelectric materials, and ceramic materials to produce nano-devices that add smartness to the textiles. The paper aims to detect the inquiry about the multi-functional properties of smart textiles for the architectural façade. The methodology follows a descriptive method to study the use of smart textiles, relying on the data collected from previous theoretical literature. A chosen case study has been described briefly and analysed to indicate the multi-functional properties of smart textile used. As a conclusion, smart textiles are used according to the purpose that is proposed by the designer. They are used to fulfil aesthetic, structural and environmental functions. The most effective property is the potentiality that has been available to create interactive and creative shapes and patterns for the architectural façade with additional sustainable multi-functions.
Improvement of the Gypseous soil properties by using Copolymer and Styrene-butadiene rubber
Authors: Ahmed Balqees A. , Al-Hadidi Maysam Th. , Mohammed Dhay Wadday 
Published: March 2020

Abstract
Gypseous soils are spread in several regions in the world including Iraq, where it covers more than 28.6% [1] of the surface region of the country. This soil, with high gypsum content causes different problems in construction and strategic projects. As a result of water flow through the soil mass, permeability and chemical arrangement of these soils vary over time due to the solubility and leaching of gypsum. In this study the soil of 36% gypsum content, is taken from one location about 100 km (62 mi) southwest of Baghdad, where the sample is taken from depth (0.5 - 1) m below the natural ground surface and mixed with (3%, 6%, 9%) of Copolymer and Styrene-butadiene Rubber to improve the engineering properties of the gypseous soil including collapsibility, permeability and shear strength. Results of the experimental work show noticeable improvement of collapsibility, permeability, and bearing capacity in soil treated with Copolymer and Styrene-butadiene Rubber compared to untreated soil.
Behavior of pile embedded in different soil types under the effect of earthquake
Authors: Sa’ur Ruba H , Shafiqu Qassun S Mohammed 
Published: March 2020

Abstract
In the seismic areas, piles are often passed through shallow loose or soft soil deposits and rest on end bearing soils. Damages due to earthquakes in piles built in layered soils occurred close to interfaces separating layers with very different shear moduli. In this study 3D finite element analyses are performed to simulate a soil-pile system under earthquake excitation in different soil types. As an example, the soil profiles of active seismic zones in Iraq will be used. For this a data base was prepared for static and dynamic parameters of different Iraq soils which were gathered and typical profiles for north, middle and south of Iraq were established. The properties of soils were then used as input dynamic data for finite element program PLAXIS 3D 2013 to study the response of single pile foundation. As earthquake input data the recording one obtained from the April 20, 2012 earthquake which hit Ali Al-Gharbi in Missan Province in Iraq was used, because this was one of the influential earthquakes. As a result the maximum bending moment occurs at the influence of different soil layers, also according to the soil-pile interaction, the deflected shape have the same behavior of pile embedded in sand and clayey soil as well as the pile that embedded in two clayey soil layers with thin sandy layers in between.
Effect of mode of vibration on the response of machine foundation on sand
Authors: Al-kaream Khalid W.Abd , Fattah Mohammed Y. , Khaled Zeyad S. M. 
Published: March 2020

Abstract
In this paper, the influence of the following parameters on different modes of vibration response of model footings on sand is studied: (vertical, rocking and pitching load amplitude and frequency). To achieve the objective of this study, the model footing was selected to be rectangular footing with an aspect ratio (L/B= 1.33) i.e (L= length and B= width). A physical model was manufactured to simulate a steady-state harmonic dynamic load applied at different operating frequencies with the same load amplitude (0.5 ton). A total of (9) cases was performed taking into account different parameters. The loading frequency ranged from (0.5) to (2) Hz and the footing was rectangular with an aspect ratio (L/B = 1.33). The soil type used was dry sand having a relative density of (50%). The behavior of the soil underneath the footing was examined by measuring the strain using a shaft encoder and the amplitude of displacement using a vibration meter. It was found that the change in vibration mode made little effect of the final strain values under the same frequency and the amplitude of displacement in (Z) direction, while the amplitude of displacement in (Y) is higher, occuring under rocking vibration and higher value amplitude of displacement in (X) direction under pitching vibration under the same frequency.
The Effect of Group of Piles on Existing Tunnel
Authors: Salim Nahla M , Lafta Sherine Jafaar 
Published: March 2020

Abstract
This work focuses on the effect of construction and loading of piles group on an existing tunnel. This was achieved by performing model tests on a sandy soil using two relative densities (50% and 70%). The experimental models include group of piles (2×1) with 3d spacing and (2×2) with 3d and 8d spacing. Three clear distances between the pile and the tunnel were chosen to be 0, 0.6 and 1.6d (d: pile diameter). The pile used is a reinforced concrete pile with 20 mm diameter and 400 mm in length, the spacing piles in pile group is chosen to be 2d and 3d. The tunnel used was a reinforced concrete tunnel with diameter of 84 mm and 780 mm length. A numerical modelling of experiments was carried out using PLAXIS-software in which the hardening soil model (HS small) has been used for modelling. The main conclusion drawn from this study is that, the stresses generated on the tunnel lining during loading are higher than during construction stages. The stresses generated on the tunnel decreases with the increase in relative density and the distance from the tip of the pile.
Application of energy absorbing layer to soil-structure interaction analysis
Authors: Abdulrasool Ahmed S. , Fattah Mohammed Y. , Salim Nahla M. 
Published: March 2020

AbstractSimulating for wave spread in geomechanics can be considered as an important subject within dynamic analysis. Chiefly, studying the soil-foundation interaction represents a stimulating matter in geotechnics studies. This paper presents the development of a reliable and efficient technique for the numerical simulation of unbounded domain (the semi-infinite extension). Absorbing layer is used to create boundaries that significantly decrease the wave reflecting into bounded area.The current work is divided into two parts. The first part is evaluation of the absorbing layer properties such as damping constants (αd,βs), modulus subgrade reaction (K), modules of elasticity (E), and natural frequency of the soil (ωn). The second part includes the dynamic analysis of strip foundation carried out by using the finite element software, OpenSees 2D. The foundation is exposed to harmony excitation and the soil is assumed as linear elastic.The results suggest that, attenuation in wave is observed once the soil’s unbounded area gets signified via the energy’s layer of absorption. Furthermore, the numerical model show that the maximum amplitude of displacement will be reduced due to the presence of absorbing layer.