bluuebunny/crossref_metadata_2025 huggingface dataset:
Drop freezing: Fine detection of contaminants by measuring the tip angle
Authors: Boulogne François , Salonen Anniina
Published: March 2020

In this Letter, we show that the shape of a freezing drop of water can be sensitive to the presence of impurities. We measure the tip angle of water drops frozen on a cold plate. The fine changes in the tip angle are robustly captured by our image analysis method, which shows a deviation from that of pure water in solutions with salt (NaCl), polymer polyethylene glycol, and surfactant tetradecyltrimethylammonium bromide starting at concentrations of 10−6, 10−4, and 10−6 M, respectively. The method could be adapted into a portable water purity tester, but this work also highlights the complexity of water freezing as it is influenced by trace concentrations of impurities.
Dust-density waves in radio-frequency discharges under magnetic fields
Authors: Melzer A. , Krüger H. , Schütt S. , Mulsow M.
Published: March 2020

Experiments on self-excited dust-density waves under various magnetic fields have been performed. For that purpose, different dust clouds of micrometer-sized dust particles were trapped in the sheath of a radio frequency discharge. The self-excited dust-density waves were studied for magnetic field strengths ranging from 0 mT to about 2 T. It was observed that the waves are very coherent at the lowest fields (B < 20 mT). At medium fields (20 mT < B<300 mT), the waves seem to feature a complex competition between different wave modes before, at even higher fields, the waves become more coherent again. At the highest fields (above 1 T), the wave activity is diminished. The corresponding wave frequencies and wavenumbers have been derived. From the comparison of the measured wave properties and a model dispersion relation, the ion density and the dust charge are extracted. Both quantities show only little variation with magnetic field strength.
Observation of spin-motive force in ferrimagnetic GdFeCo alloy films
Authors: Fukuda Shun , Awano Hiroyuki , Tanabe Kenji
Published: March 2020

Non-uniform magnetic structures produce emergent electromagnetic phenomena such as the topological Hall effect and the spin-motive force (SMF). The experimental reports on the SMF, however, are very few, and the relationship between the SMF and material parameters is still unclear. In this study, we investigated the SMF in ferrimagnetic GdFeCo alloy films using the spin-torque-induced ferromagnetic resonance method and clarified the relationship. The amplitude of the detected SMF becomes larger than that of the transition metal alloy FeCo by Gd doping and reaches the maximum near a Gd composition of the boundary between in-plane and perpendicularly magnetized films. According to the analytical calculation, the enhancement is related to the trajectory of the magnetization precession. Moreover, we find that the SMF induced by the magnetic resonance is inversely proportional to the square of the damping constant.
Effects of replacing starch with three sugars in a concentrate and forage diet on in vitro rumen fermentation, fatty acid composition and related bacteria
Authors: Sun X. Q. , Wang Y. P. , Wei R. Y. , Chen B. , Zhao X.
Published: March 2020

Context Replacing starch with sugar could maintain dietary energy density with reduced risks of rumen acidosis and milk fat depression, but the underlying mechanism is not well understood, and the effects of sugar feeding might vary among sugars. Aims Objectives of the present study were to evaluate the effects of replacing corn starch in a diet containing 40:60 forage-to-concentrate ratio (control) with 3%, 6% and 9% of sucrose, fructose and lactose on in vitro rumen fermentation, fatty acid (FA) composition and populations of bacteria involved in the production of trans-11 and trans-10 FA. Methods A 3 × 3 + 1 (control) factorial experimental design was used, and the pH, concentrations of volatile fatty acids (VFA) and ammonia-N, profiles of FA and the relative abundance of four trans-11-producing bacteria and two trans-10 FA-producing bacteria were measured after a 6-h incubation. Key results Replacing dietary corn starch with sucrose, fructose and lactose neither altered the concentration of total VFA after 6-h fermentation, nor decreased the pH, except for substitution with 9% sucrose. Increased butyrate proportions and decreased branched-chain VFA proportions were the common effects in sugar treatments, but the proportions of acetate and propionate varied among sugars. Lactose inclusion in the diet led to a higher pH, greater acetate and butyrate concentrations, and lower propionate concentrations than did sucrose inclusion. Sugar substitution decreased the concentrations of C18:1 trans-4 and most C18:2 isomers, but did not influence the major isomers related to trans-11 and trans-10 biohydrogenation pathways. Abundance of the four measured trans-11 FA-producing bacteria was increased by sugars, with sucrose showing a greater influence than did fructose and lactose. As to trans-10 FA-producing bacteria, only Megasphaera elsdenii populations were decreased by 3% and 6% fructose inclusion compared with the control. Dose-effect varied among sugars and the parameters measured, with sucrose having the most obvious dose effect among the three sugars; however, fructose affected mainly fermentation parameters, while lactose affected mainly C18 FA profiles. Conclusions Replacing corn starch in a high-concentrate diet with up to 9% of sucrose, fructose and lactose differentially affected rumen fermentation and rumen FA metabolism, by influencing the abundance of rumen bacteria involved in rumen FA biohydrogenation. Implications Lactose may be more efficient in increasing milk fat than are sucrose and fructose, and dose effect should be considered in the utilisation of sucrose.
Milk yield at first lactation, parity, and season of calving affect the reproductive performance of water buffalo cows
Authors: Nava-Trujillo Héctor , Valeris-Chacin Robert , Quintero-Moreno Armando , Escalona-Muñoz Juan
Published: March 2020

Context Profitability of water buffalo systems depends on a calving interval (CI) <400 days. Several factors affect the achievement of this target. However, milk yield at first lactation has received little attention. Aims Determine the effect of milk yield at first lactation, parity, season of calving and farm, on the length of CI and the probability of a CI ≤ 400 days in water buffaloes. Methods A retrospective analysis of milk yield at first lactation and reproductive records of 1459 water buffaloes was carried out. Milk yield was categorised as Group 1 (≤1090 kg), Group 2 (1090–1377 kg), Group 3 (1377–1684 kg) and Group 4 (>1684 kg); parity was categorised as parity 1, 2 and ≥ 3; and month of calving was grouped into three seasons: December–March, April–July, and August–November. Data were analysed using linear and logistic mixed models. Key results CI increased from 425.3 days (95% CI: 418.8–431.8 days) in group 1 to 463.3 days (95% CI: 456–470.6 days) in group 4 (P < 0.05), while the probability of having a CI ≤ 400 days decreased from 0.5 (95% CI: 0.46–0.54) to 0.26 (95% CI: 0.22–0.29), respectively (P < 0.05). CI decreased from 466 days (95% CI: 460.8–471.3 days) in parity 1 to 410.5 days (95% CI: 405.2–415.8 days) in parity ≥3, whereas the probability of a CI ≤ 400 days increased from 0.26 (95% CI: 0.24–0.29) to 0.51 (95% CI: 0.47–0.54) respectively (P < 0.05). Water buffaloes calving in August–November showed significantly shorter CI and, along with those calving between December–March, showed the highest probability of a CI ≤ 400 days. An interaction between milk yield at first lactation and parity on both outcomes was observed. Conclusions Shorter CI and higher probability of a CI <400 days were associated with lower milk yields at first lactation, higher parity and calving between August–November. Higher milk yield at first lactation affected negatively the reproductive performance of water buffaloes, especially at parity 1 and 2. Implications These results highlight the importance of adequate nutritional management to allow water buffaloes to cope with the challenge of the postpartum negative energy balance and have a calving interval less than 400 days.
Language, Script, and Advertising in India’s Hindi Belt: Institutional Voices in Flux
Authors: LaDousa Chaise
Published: March 2020

Certain combinations of languages and scripts have come to take on indexical properties within the world of advertising in northern India. Such properties are regimented by what is on offer—commercial items, government services and information, schooling, and coaching services. An exploration of changing conventions in advertising since the 1990s, a period of accelerated liberalization in India, reveals that there have been especially dramatic changes in education and coaching services. By considering combinations of language and script as partly constitutive of the voice of an institution, this article accounts for the changing possibilities for the articulation of institutional distinctions and the ways institutional voices commoditize aspects of personae during the last twenty-five years or so in northern India.
Putting Our Scripts in Their Mouths: Orthography, Semiotic Ideologies, and the Embodied Publics of Name Changes in Eastern India
Authors: Martineau Katherine B.
Published: March 2020

This is a case study of an official orthographic change in eastern India, which I approach as a debate about semiotic ideologies. In 2012, an Indian constitutional amendment changed the names of one of India’s eastern states, Odisha, and its state language, Odia, in Devanagari and Roman scripts. Building on recent studies of multilingual and multiscriptal orthographies on public signs, I examine official parliamentary and popular media arguments about the orthographic correspondences between Odia, English, and Hindi names for the state and its language. As the debaters propose contrasting models of official naming and justify them, they build on different orientations to the material embodiments of linguistic signs. These different assumptions also support contrasting social imaginaries of Odisha in relationship to the nation. This article proposes that orientations to the body and embodiment can be an important component of the semiotic ideologies of orthography.
The progression of thermodynamic anomalies in MX2 networks with local tetrahedral geometries
Authors: Fijan Domagoj , Wilson Mark
Published: March 2020

Key thermodynamic anomalies in density and compressibility, as well as the related stability limits, are determined using an ionic model for BeF2 which includes many-body polarization terms. BeF2 is chosen as an example of an archetypal network-forming system whose structure can be rationalised in terms of connected local tetrahedral coordination polyhedra. The anion dipole polarizability (which effectively controls the bond angles linking neighbouring tetrahedra) is used as a single free parameter in order to help rationalise the changes in the anomaly locations in phase space, whilst all other potential parameters remain fixed. The anomalies and stability limits systematically shift to lower temperature and higher pressure as the anion polarizability is increased. At high dipole polarizabilities the temperature of maximum density anomaly locus becomes suppressed into the supercooled regime of the phase space. The movements of the anomaly loci are analysed in terms of the network structure and the correlation with the inter-tetrahedral bond angles is considered. The high sensitivity of the anomalies to the details of the potential models applied is discussed with reference to previous works on related systems. The relationship to analogous studies on Stillinger–Weber liquids is discussed.
Quantum fluctuation of entanglement for accelerated two-level detectors*
Authors: Zhang Si-Xuan , Liu Tong-Hua , Cao Shuo , Liu Yu-Ting , Geng Shuai-Bo , Lian Yu-Jie
Published: March 2020

It is well known that the quantum fluctuation of entanglement (QFE) between Unruh–De Witt detector (modeled by a two-level atom) is always investigated in a relativistic setting. However, both of the Unruh radiation and quantum fluctuation effects play an important role in precise measurements of quantum entanglement. In this paper, we have quantitatively analyzed how the relativistic motion affects the QFE for two entangled Unruh–De Witt detectors, one of which is accelerated and interacting with the neighbor external scalar field. Our results show that the QFE, which initially increases by the Unruh thermal noise, will suddenly decay when the acceleration reaches to a considerably large value. Therefore, the relativistic effect will lead to non-negligible QFE effect. We also find that the initial QFE (without acceleration effect) reaches its minimum value at the maximally entangled state and the separable state. More importantly, our analysis demonstrates that although the QFE has a huge decay when the acceleration is greater than ∼0.96, the ratio of ΔE/C is still very large, due to the simultaneous decay of concurrence to a very low value. Finally, enlightened by the well-known equivalence principle, we discuss the possibility of applying the above findings to the dynamics of QFE under the influence of gravitation field.
Insulator-metal transition in CaTiO3 quantum dots induced by ultrafast laser pulses*
Authors: Liu Tong , Zhang Hong , Cheng Xin-Lu
Published: March 2020

According to time-dependent density functional theory (TDDFT), we study the interactions between ultra-fast laser pulses and two kinds of calcium titanate quantum dots (PCTO-QDs and MCTO-QDs). Under the action of localized field effect, ultrafast laser can induce quantum dots to make the transition from insulator to metal. The PCTO-QDs are ultimately metallic, while the MCTO-QDs are still insulator after experiencing metal state. This is bacause the stability of the unsaturated atoms in the outermost layer of PCTO-QDs is weak and the geometric configuration of MCTO-QDs as a potential well will also reduce the damage of laser. Moreover, laser waveforms approaching to the intrinsic frequency of quantum dots tend to cause the highest electron levels to cross the Fermi surface. In this paper, it is reported that the insulating quantum dots can be transformed into metal by adjusting the intensity and frequency of laser. The importance of local morphology is emphasized by comparing two kinds of CTO-QDs. More importantly, it is an important step to identify the potential properties of perovskite materials.
Energy cooperation in quantum thermoelectric systems with multiple electric currents*
Authors: Liu Yefeng , Lu Jincheng , Wang Rongqian , Wang Chen , Jiang Jian-Hua
Published: March 2020

The energy efficiency and output power of a quantum thermoelectric system with multiple electric currents and only one heat current are studied. The system is connected to the hot heat bath (cold bath) through one terminal (multiple terminals). In such configurations, there are multiple thermoelectric effects coexisting in the system. Using the Landauer–Büttiker formalism, we show that the cooperation between the two thermoelectric effects in the three-terminal thermoelectric systems can lead to markedly improved performance of the heat engine. Such improvement also occurs in four-terminal thermoelectric heat engines with three output electric currents. Cooperative effects in these multi-terminal thermoelectric systems can considerably enlarge the physical parameter region that realizes high energy efficiency and output power. For refrigeration, we find that the energy efficiency can also be substantially improved by exploiting the cooperative effects in multi-terminal thermoelectric systems. All these results reveal a useful approach toward high-performance thermoelectric energy conversion in multi-terminal mesoscopic systems.
Generation of tripartite Einstein–Podolsky–Rosen steering by cascaded nonlinear process*
Authors: Liu Yu , Liang Su-Ling , Jin Guang-Ri , Yu You-Bin , Lan Jian-Yu , He Xiao-Bin , Guo Kang-Xian
Published: March 2020

A scheme is proposed to generate genuine tripartite Einstein–Podolsky–Rosen (EPR) steering in cascaded nonlinear process of the fourth-harmonic generation. The second-harmonic is generated by the first double-frequency process in an optical superlattice. Then, the fourth-harmonic is produced by the second cascaded double-frequency process through quasi-phase-matching technique in the same optical superlattice. The genuine tripartite EPR steering among the pump, the second-harmonic, and the fourth-harmonic beams can be obtained by this cascaded nonlinear process according to a criterion for genuine multipartite quantum steering. The quantum steering properties are discussed by adjusting the parameters related to the cascaded nonlinear system. The present research provides a reference scheme and data for obtaining good multipartite EPR steering in experiment and can advance the applications of quantum steering in the quantum information processing.
Multicaloric and coupled-caloric effects*
Authors: Hao Jia-Zheng , Hu Feng-Xia , Yu Zi-Bing , Shen Fei-Ran , Zhou Hou-Bo , Gao Yi-Hong , Qiao Kai-Ming , Li Jia , Zhang Cheng , Liang Wen-Hui , Wang Jing , He Jun , Sun Ji-Rong , Shen Bao-Gen
Published: March 2020

The multicaloric effect refers to the thermal response of a solid material driven by simultaneous or sequential application of more than one type of external field. For practical applications, the multicaloric effect is a potentially interesting strategy to improve the efficiency of refrigeration devices. Here, the state of the art in multi-field driven multicaloric effect is reviewed. The phenomenology and fundamental thermodynamics of the multicaloric effect are well established. A number of theoretical and experimental research approaches are covered. At present, the theoretical understanding of the multicaloric effect is thorough. However, due to the limitation of the current experimental technology, the experimental approach is still in progress. All these researches indicated that the thermal response and effective reversibility of multiferroic materials can be improved through multicaloric cycles to overcome the inherent limitations of the physical mechanisms behind single-field-induced caloric effects. Finally, the viewpoint of further developments is presented.
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

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

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

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

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

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

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

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

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

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

The 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

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

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

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

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

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

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

Simulating 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.
Bearing capacity of piles in unsaturated soil from theoretical and experimental approaches
Authors: al-Omari Raid R. , Fattah Mohammed Y. , Kallawi Abbas M.
Published: March 2020

Research in unsaturated soil mechanics has considerably developed in the past decades, through the simultaneous development of experimental investigations and theoretical analyses. A fundamental property of unsaturated soil is the ability to store and release water.

In this study, an attempt was made to compare the results of bearing capacity of model pile groups constructed in saturated soil prepared at two dry densities and unsaturated soil, with results from theoretical approach (conventional and modified)α, βandλmethods. Square aluminum model piles of 20 x 20 mm in cross section and 200 mm in length were used. The piles were arranged in six group configurations, single, 2×1, 3×1, 2×2, 3×2, and 3×3, groups in addition to pull out test at which the pile is designed to verify this purpose. All groups have the same spacing, which is equal to 3 pile diameters (60 mm). The results showed that using the β method gives the value of ultimate capacity close to the experimental results for saturated and unsaturated tests, while the theoretical results showed overestimation when using other two methods. The results of load displacement curves for piles embedded in soil having three different properties indicate an increase in the ultimate pile load carrying capacity with increase in the number of piles for different soil properties. This increase however, is not linear and gives a high value when the soil becomes in unsaturated state compared to the soil in saturated state.
Analysis of piled raft foundation in sandy soil using full scale models
Authors: Hussein H H , Karim H H , Shlash K T
Published: March 2020

The conduct of the piled raft foundation system is measured by using different methods. Full scale loading tests were conducted on 18 full scale models consistent with ASTM D1143-07, so as to get actual behavior. The experiment study included carrying out still field load testing for piles fixed in sand soils in Karbala province, these piles are viewed as pioneers within this area. Testing was conducted for Six groups of piles (1×1, 1×2, 3 heaps, 2×2, 5 pile and 2×3). Every group comprised of three states; pile group, just rafts as well as piled rafts, accordingly, a sum of 18 still load testing were done. It was inferred that the piled raft basis diminishes the sum settling as well as prompts increment of the bearing limit more than the piles’ groups along with the raft basis. The loading that was shared via the raft basis is approximately (46.3, 28.5, 27.6, 26.4, 25.7 and 25%) regarding the groups of piled raft (1×1, 1×2, 3 piles, 2×2, 5 piles as well as 2×3), individually. The instance of pilled raft basis can be taken as the basic state on the grounds that the raft basis has no loading share until the piles’ group achieves the completely preparing state. It was seen that the pile achieves this state as the connected loading is in the scope of (40-60%) of the sum burden, after which the raft participates loading share, and afterward it will be failed before pile.
Implementation of the Space and Terrestrial information to Use Geological Deposits in Engineering Construction in Western Desert/Iraq
Authors: Abdulrazzaq Raad M.Wafur
Published: March 2020

It is possible to study the locations of the geological deposits for various construction projects, which were indicated by our study and the new method used in construction.

In the Western Desert/Anbar province in general and the Gaara Depression the area of study especially, and some other surrounding areas. The area of the study contains a special lithological sequence consisting of several configurations. This sequence extends from the hard rock at the top to the fragile rocks beneath it, it is, therefore, easy to construct, in formations whose rocks are fragile by digging through them easily and at low cost, by removing them from hard rock, such as building inside a cave. In addition, the hard rocks constitute the natural protection of buildings, civilian and military projects built underneath, so hard geological rocks naturally protect the buildings, besides these are low in cost, compared to similar projects on the surface of the earth, which need to special engineering techniques and high cost of the securities. While the buildings of our research completely protected from most directions and the natural disasters, such as earthquakes, floods, hurricanes or terrorists and terrorist operations, through the hard rock cover.
Behavior of grouting pile in sandy soil
Authors: Hussein H H
Published: March 2020

An old project was built in south of Iraq. This project included housing and buildings for common use. Pile foundations were needed in some parts, where sandy lean clay and medium dense silty sand existed at different depths. Small diameter friction piles were used in this part of the project. Micro piles are used in the same manner as the conventional piles in combination with caps. They can also be used to reduce excessive settlement. In the load test program vertical, tensile and lateral loading tests were performed to study the efficiency of this type of piles. For the current work, Full-scale pile loading testing has been done to examine the field performance of the micro piles subjected to tension, lateral and compressing loads. The observations have provided some conclusion. Installing the micro piling within all soils represents a method of improving procedure done to a ground. Micro piles can be used a normal foundation piles. The work of this paper pointed to, without plunging failing, Butler and Hoy’s strategy gives a well estimating of a definitive uplifting limit. This study has shown that, once micro-piles have been provided with a higher casing section, carrying capacity of piles may be increase by more than 90% in comparison with micro-piles that have no case. Tensile loads ratio represents 25% of the compression loads. A final observation is that the micro piles have sensitivity toward the constructing method as well as the drilling bit specification.