bluuebunny/crossref_metadata_2025 huggingface dataset:
Reviewing manuscripts for academic journals
Authors: Sachs Rebecca
Published: March 2020

Reviewing manuscripts for academic journals not only
contributes to the advancement of knowledge and the development of fellow
researchers, but also holds numerous advantages for the reviewers
themselves. After a brief explanation of what reviewing is and how it works,
this chapter describes some of the benefits of reviewing; provides guidance
regarding how to write fair, reasonable, meaningful, systematic, specific,
improvement-oriented reviews; raises factors to consider in decision-making;
offers advice for balancing reviewing against other professional priorities
and obligations; and seeks to answer a variety of practical “how-to” and
“what-if” questions that might arise in the process. Approached with a
constructive and strategic mindset, reviewing offers valuable opportunities
for graduate students and new faculty to grow intellectually and
professionally, influence and promote progress in the field, enhance their
reputations, and establish themselves as engaged members of a research
community in ways that will stand them in good stead throughout their
careers.
Crossing over
Authors: Tannen Deborah
Published: March 2020

Drawing on my own experience, I address some of the
challenges and benefits of writing for both academic and general audiences.
I note, for example, that when I write for general audiences, I can’t say
much of what I know because it would take too long to explain. In my
academic writing, I can’t say much of what I know because I can’t prove it.
Among the challenges are the scorn for and misconceptions about each world
that are held by denizens of the other. Perhaps the most challenging aspect
of moving from academic to trade publishing is not the writing itself but
getting published. To illustrate, I recount the tortuous sagas behind the
publication of my first two general-audience books. I conclude by observing
that understanding the vicissitudes of writing for these two audiences sheds
light on how language works.
CD109 antigen-like gene is induced by ecdysone signaling and involved in the cellular immunity of Helicoverpa armigera
Authors: Jiang Di , Du Xuemeng , Wang Cuiyan , Zhang Shisong , Wang Gang
Published: March 2020

Cellular immunity is evolutionarily conserved in invertebrates and vertebrates. In insects, cellular immune response is provided by the hemocytes, and its molecular mechanisms are currently not fully understood. Here, we identified a CD109 antigen-like gene (HaCD109) from Helicoverpa armigera which is highly expressed in the hemocytes of larvae. Stimulation by Escherichia coli and chromatography beads significantly upregulated HaCD109 expression. In vivo HaCD109 silencing significantly increased bacterial load in larval hemolymphs and reduced the hemocyte spread. 20-Hydroxyecdysone (20E) can induce HaCD109 expression through its receptors, EcR and USP. In vivo HaCD109 silencing nearly abolished 20E-induced bacterial clearance and hemocyte spread. These results suggested that HaCD109 plays an important role in cellular immunity, and the 20E-induced cellular immune response in H. armigera requires HaCD109 involvement. Our study contributes to the understanding of regulatory mechanisms for innate immune response and provides new insights into the interaction between innate immunity and steroid hormone signaling.
Intratumoral accumulation of gut microbiota facilitates CD47-based immunotherapy via STING signaling
Authors: Shi Yaoyao , Zheng Wenxin , Yang Kaiting , Harris Katharine G. , Ni Kaiyuan , Xue Lai , Lin Wenbin , Chang Eugene B. , Weichselbaum Ralph R. , Fu Yang-Xin
Published: March 2020

Most studies focus on how intestinal microbiota influence cancer immunotherapy through activating gut immunity. However, immunotherapies related to innate responses such as CD47 blockade rely on the rapid immune responses within the tumor microenvironment. Using one defined anaerobic gut microbiota to track whether microbiota interact with host immunity, we observed that Bifidobacterium facilitates local anti-CD47 immunotherapy on tumor tissues through the capacity to accumulate within the tumor microenvironment. Systemic administration of Bifidobacterium leads to its accumulation within the tumor and converts the nonresponder mice into responders to anti-CD47 immunotherapy in a stimulator of interferon genes (STING)– and interferon-dependent fashion. Local delivery of Bifidobacterium potently stimulates STING signaling and increases cross-priming of dendritic cells after anti-CD47 treatment. Our study identifies the mechanism by which gut microbiota preferentially colonize in tumor sites and facilitate immunotherapy via STING signaling.
Development and evaluation of a novel analyser for ISO14687 hydrogen purity analysis
Authors: Arrhenius K , Büker Oliver , Fischer Andreas , Persijn Stefan , Moore Niamh D
Published: March 2020

Standards ISO14687 and EN17124 set stringent limits for numerous gaseous impurities and particulates that may damage the fuel cell system in a hydrogen vehicle, as it is highly sensitive to the presence of even very low levels of impurities. However, performing the whole set of analyses is both technically challenging and time-consuming for any laboratory and will require a combination of several analytical techniques or instruments. In this study, we discussed the selection of analytical techniques for hydrogen purity testing in order to optimize the CAPEX (capital expenditure) and OPEX (operational expenditure), while ensuring the quality of the results and the compliance of the analytical methods with ISO21087. Among the individual impurities to be analysed in ISO14687, spectroscopy techniques are suitable for ammonia, carbon dioxide, carbon monoxide, formaldehyde, formic acid, oxygen and water. Spectroscopy techniques are even suitable for some impurities belonging to the three total species such as hydrogen sulphide, hydrogen chloride and methane. However, helium and argon, which are monoatomic, do not exhibit response in the infrared region. Therefore, any spectroscopic analysis method must be completed by another method in order to simultaneously analyse all individual gaseous impurities from ISO14687. In this study, we constructed and demonstrated the feasibility of an instrument composed of a gas chromatograph having three columns (two packed columns and a PLOT (Porous Layer Open Tubular) column and two detectors (FID and TCD) coupled in parallel to two OFCEAS instruments using reference gas mixtures. Finally, we also proposed an extended configuration that will allow performing the whole set of analyses for gaseous species from ISO14687.
ARRAW: anti-resonant reflecting acoustic waveguides
Authors: Schmidt M K , O’Brien M C , Steel M J , Poulton C G
Published: March 2020

Development of acoustic and optoacoustic on-chip technologies calls for new solutions to guiding, storing and interfacing acoustic and optical waves in integrated silicon-on-insulator systems. One of the biggest challenges in this field is to suppress the radiative dissipation of the propagating acoustic waves, while co-localizing the optical and acoustic fields in the same region of an integrated waveguide. Here we address this problem by introducing anti-resonant reflecting acoustic waveguides (ARRAWs)—mechanical analogues of the anti-resonant reflecting optical waveguides. We discuss the principles of anti-resonant guidance and establish guidelines for designing efficient ARRAWs. Finally, we demonstrate examples of the simplest silicon/silica ARRAW platforms that can simultaneously serve as near-IR optical waveguides, and support strong backward Brillouin scattering.
Stochastic resetting and applications
Authors: Evans Martin R , Majumdar Satya N , Schehr Grégory
Published: March 2020

In this topical review we consider stochastic processes under resetting, which have attracted a lot of attention in recent years. We begin with the simple example of a diffusive particle whose position is reset randomly in time with a constant rate r, which corresponds to Poissonian resetting, to some fixed point (e.g. its initial position). This simple system already exhibits the main features of interest induced by resetting: (i) the system reaches a nontrivial nonequilibrium stationary state (ii) the mean time for the particle to reach a target is finite and has a minimum, optimal, value as a function of the resetting rate r. We then generalise to an arbitrary stochastic process (e.g. Lévy flights or fractional Brownian motion) and non-Poissonian resetting (e.g. power-law waiting time distribution for intervals between resetting events). We go on to discuss multiparticle systems as well as extended systems, such as fluctuating interfaces, under resetting. We also consider resetting with memory which implies resetting the process to some randomly selected previous time. Finally we give an overview of recent developments and applications in the field.
Effect of web openings on effective flange width of reinforced concrete T-section
Authors: Sayhood E K , Mohammed N S , Hanon A S
Published: March 2020

In this study an evaluation of empirical formula is carried out for effective flange width with and without web openings based on previous experimental results. The results of empirical equation were compared with the codes of practice formulas such as ACI 318M-14, BS8110, AS 3600 and CSA. Also, three researchers’ equations without the effect of web opening are used to compare with the results of the present study. Square and circular web openings with different size and locations are studied. The effect of compressive strength (

f
c
'

), flange reinforcement (ρf
), flexural reinforcement (ρw
), shear reinforcement (ρv
), thickness of flange (hf
) and clear span (ln
) are investigated and included in the suggested formula. Finally, the previous researcher’s equations are modified to include the effect of web openings on effective flange width.
Stress-strain behavior of normal and high strength self-compacting concrete
Authors: Mohammed Mohammed Hashim
Published: March 2020

This paper presents an experimental investigation on stress-strain behavior of normal and high strength self-compacting concrete with two different maximum aggregate sizes. Eight mixes are adopted for this purpose with nominal compressive strength ranging from 20 to 80 MPa and maximum aggregate size of 10 and 20 mm. Results show that the ascending parts of the stress-strain curves become steeper as the compressive strength increases and maximum aggregate size decreases. Strain at failure increases with the increase in compressive strength and maximum aggregate size. Also, changing maximum aggregate size from 10 to 20 mm, generally, increases compressive strength (up to 13.97% for cylinders and 17.24% for cubes) and modulus of elasticity (up to 19.27%).
Flexural behavior of self-compacting concrete voided slabs under monotonic loads
Authors: Al-shaarbaf Ihsan A. , Amar Abbas Ali , Ahmed Mohammed A.
Published: March 2020

This research is devoted to investigate the experimental behavior of normal and moderately high strength self-compacted concrete (SCC) voided slab strips under monotonic loading regimes. Five one-way simply supported slabs were tested including one as a reference slab (solid slab) and the remaining four as voided slabs with three cases of reduction in cross sectional area (6.5%, 13.1% and 14.7%) by creating longitudinal, 3 voids of 50 mm diameter, 6 voids of 50 mm diameter and 3 voids of 75 mm diameter, respectively. The experimental results revealed that for moderate thick reinforced normal SCC one way slab (3 void, dia. =75mm), the ultimate load was reduced by about 20% and the deflection at ultimate load was decreased by about 11% relative to the reference solid slab. While for similar voided slab of moderate high strength SCC, the ultimate load was increased by about 48.3% and the deflection at ultimate load also raised by about 27% with respect to normal strength SCC slab. In addition, the experimental results indicated that for moderate thick reinforced normal SCC one way slab having (3 voids, dia. =50 mm), the ultimate strength was reduced by about 6.7% and the deflection at ultimate load was reduced by 38%, when compared to the solid reference slab. However, for similar slab with (6 void, dia. =50 mm), the reduction in the ultimate strength and deflection at ultimate load were about 9.3% and 42%, respectively.
Flexural behavior of hybrid ultra-high-performance concrete
Authors: Danha L S , Abdul-hussien Z A , Abduljabbar M S , Yassin L A G
Published: March 2020

Ultra-high performance fiber reinforced concrete has superior mechanical and structural properties but the major drawback of this new construction material is its high cost. This research presents an experimental study to investigate the flexural behavior of hybrid ultra-high-performance concrete with different steel fibers’ volume fractions, cast in full and partial depths of specimen’s cross sections to exploit the advantages of steel fibers in optimal way. The variables studied included the percentages of steel fibers used (0, 1, 2 and 3) % and the fraction of depth containing the steel fibers (0.25, 0.5, 0.75 and 1). Experimental results show that the failure load increases with the increase in the fraction of depth where the steel fibers were distributed. This increase was more significant as the fraction of depth increases from 0.25 to 0.5 and 0.75. As it reached the 0.75 the increase was none pronounced, and the failure load was almost similar to that of full depth. Therefore, it can be concluded that the maximum effective fraction of depth would be 0.75. It was noted that the different distribution of the same amount of the steel fibers within the depth of the section greatly affects the specimen load capacity and using the steel fibers in the tension zone effectively enhances the flexural performance of UHPFRC. The results also indicate that increasing the steel fiber volumetric ratio from 0% to 1%, 2% and 3% the percentages of increase in the failure load (Pf) with respect to the control specimen were 156%, 261% and 389%, respectively.
Effective length and area of bolted steel plates attached externally to strengthen reinforced concrete beams
Authors: Abtan Yaarub G
Published: March 2020

In this research an investigation has been done on eight reinforced concrete beams. Each beam was strengthened by bolted steel plates attached to their bottom side, of which length and thickness ratio varied, except one beam which has been tested without steel plate as controlling test. Two limits have been introduced upon the maximum plate area used and its minimum length. The first limit is to insure a ductile tension failure, and the latter is to prevent loss of interaction between the two components. Bolts with head were used to provide suitable connection through the specimens of concrete beams and the steel plates through predrilled holes in the steel plates. All beams have similar dimensions and tested simply supported over an effective length of 1600 mm and loaded with central load. Test results show that the plated beam gain an increase in strength over that of unplated beam of about 145%. Also, beams with relatively thin plates, the plate length has little effect upon the ultimate strength, however, for beams with thicker plates the results show a decrease in strength of about 16%.
Development of steel structure connections for seismic resistance using composite steel bolts/rubber
Authors: Ali Suhaib. J. , Ibrahim Amer M. , Shafeeq Sarmad
Published: March 2020

This study scoped to develop the connections of steel structures using composite steel bolts/rubber to connect beam-to columns joints of steel structures instead of conventional steel bolts. Four steel plane portal frames were tested under horizontal cyclic quasi-static load. The study included testing different diameters of composite steel bolts/rubber: 0.5dbolt
, 1.0dbolt
, and 1.5dbolt
, that are used to connect the beam with columns and these results were compared with traditional beam-to columns connections without rubber. The rubberized connections are working at high structural standards through reducing the effect of the stresses resulting from the earthquakes by absorbing damping process. They protect the bolts that are used in joints of steel structures from corrosion due to friction, and they are economically feasible because the rubber that was used for covering the bolts is taken from old tires. The experimental tests proved that using the rubber material around the bolts as much as one - half times bolt diameter raises the specimen’s resistance by 166.66%, increases the displacement by 163.30%, and reduces the strain by 48.13%, as compared with bolts that do not have a rubber (steel bolts only). All these results will be discussed in detail in this report.
Semi-Active Control Performance Index for magneto-rheological dampers considering s-structure interaction
Authors: Yanik Arcan
Published: March 2020

In this study, an instantaneous optimal control performance index for structures with magneto-rheological (MR) dampers is analytically defined. Absolute acceleration and absolute velocity feedback are implemented to this simple performance index. The performance index is another application of instantaneous optimal control algorithms. A three story structure incorporating an MR damper is presented as a numerical example. Modified Bouc Wen damper force model is used for obtaining the MR damper force. The electrical current need for the operation of the MR damper is taken into account by using a piece wise invertible MR damper model. Near fault earthquakes are used in the dynamic simulations. Seismic energy-based evaluations are carried out. Uncontrolled structural response reduction performance and power requirement of the MR damper is investigated. The analysis shows that proposed performance index is effective in reducing uncontrolled structural seismic responses.
Adaptation of local wisdom in contemporary mosque design for achieving good building physics and earthquake resistance
Authors: Sari Laina Hilma , Izziah  , Meutia Erna
Published: March 2020

The paper aims at proposing the implication of the local wisdom value in designing a contemporary mosque. Local wisdom works successfully in determining a suitable design of vernacular buildings such as traditional mosque. It comprises the considerations on building physics such as sufficient thermal comfort, good daylighting and room acoustics which meets the standard. These parameters are also running fitly with traditional wooden structure of the mosque which is resistant against the earthquake. This article analyses two old mosques in Aceh, Indonesia which are still well standing across their ages. The wooden mosques are Indrapuri mosque in Aceh Besar and Tengku Dipucok Krueng Mosque in Pidie Jaya. The evaluation of the mosques was carried out through observations and some field measurements. This article further examines the adaptations of the local wisdom of the mosque pertaining the buildingphysics and the earthquake resistance that can be applied in the contemporary mosque.
Nonlinear analysis of hybrid reinforced concrete beams under flexural load
Authors: Mohsin Saja Jabbar , Mohammed Nisreen S.
Published: March 2020

In recent years, concrete having a compressive strength of 60 MPa and more is being used for high-rise buildings and long span bridges, but high strength concrete is more expensive than normal strength concrete and became commercially used in engineering construction. This material has to be placed where it should be in order to get an economical consideration.

This study introduces analyses of a new two layers reinforced concrete beam where high strength concrete in the compression zone and normal strength concrete in the tension zone are assumed based on experiences of previous laboratory.

The beam specimens were solved numerically using nonlinear finite element program provided by ABAQUS 6.12 software for static load to verify the same using experiment. An agreement between analysis and experimental results was obtained, and less than 11.4% has been put as acceptable limit.
Seismic Performance Assessment of Istanbul Airport Viaduct According to Turkish Building Seismic Code 2007 by Pushover Analysis
Authors: ŞEngÜl Ecem , GÜler Kadir , GÜler M.Gökhan
Published: March 2020

The goal of this study is to examine and evaluate the structural system and seismic performance of the viaduct which is located the west side of the Istanbul Airport. For this purpose, a three-dimensional structural system of the viaduct is modeled by using SAP2000 (Structural Analysis Program) software. The piers of the viaduct consist of two columns. It connects the terminal building and the parking building to each other, twelve spans and designed according to AASHTO (2002). Earthquake effects are considered in the transverse and longitudinal directions by taking into account the site-specific response spectra. The pre-stressed and precast girders which is used in the deck of the viaduct is designed under bending moment and shear force effects considering service loads, such as self-weight and traffic loads. The pre-stress losses and deflection checks are carried out to satisfy the serviceability conditions of the viaduct deck. The elements of the viaduct, such as pier cap, piers and foundation were designed by considering the vertical and lateral loads, so required cross-sections and reinforcement area are determined. In the present paper earthquake performance evaluation of the viaduct is accomplished according to the Turkish Building Seismic Code 2007 (TBSC 2007). Performance evaluation of the viaduct is carried out by applying static pushover analysis, one of the non-linear analysis methods, is applied to the pier located at the middle axis of the viaduct. Under lateral loading, the plastic hinges are developed at the bottom ends of the piers, as anticipated. In the performance evaluation of viaduct piers, the earthquake effect with 10% probability of exceedance over 50 years is considered adopting the parameters given TBSC 2007, whereas the parameters which define the spectrum compared to the Seismic Code of DLH (2007) code. Numerical results are given in tables and figures, comparatively.
Effect of external prestressing strands on the Yielding Stage behaviours of steel beams
Authors: Mahmoud Kamal Sh. , Yousif Mustafa A. , Rasheed Mohammed M.
Published: March 2020

Seven steel beams were tested under one point load to investigate the effect of existence of external prestressing strands on the behavior of steel beams at yielding stage. All steel beams have the same gross area, overall length and the strengthened specimens are employed by two low relaxation strands. The steel beams are divided into two groups according to existence of prestressing strands, the first group involves one steel beam which is considered as a reference beam, while, the second group involves six specimens divided according to the location of prestressing strand (e) at jacking stress (fpj =1120.061 MPa). During the tests, it can be noted that the load strain response for strengthened steel beams are stiffer and the increasing percent of stiffening increases with the increasing of strand eccentricity and the maximum yielding load of strengthened tested beams increases with the increasing of strand eccentricity and the maximum enhancement in yielding load of strengthened tested beams reaches to 126.331% in the OM234 sample compared with the reference beam. Also, it was found that the yielding strain positions changed from bottom flange to the top region for the strengthened tested beams as compared with the reference steel beam and the increasing percent in the yielding to ultimate load ratio (Py/Pu) for the strengthened tested beams increases with the increasing of strand eccentricity at constant applied jacking stress. The maximum percentage increase in yielding to ultimate load ratio (Py/Pu) of strengthened tested beams reaches to 21.06% in the Straight strand profile as defined by OM234 sample as compared with the reference beam.
Behavior of hybrid reinforced concrete columns
Authors: Hamid Marawan M , Yassin Layla A G , Mohammed Alyaa H
Published: March 2020

This paper involves an experimental investigation to study the behavior of short rectangular columns cast with hybrid concrete, to compare the strength, stiffness and toughness provided by the hybrid structural system and the results collected may be used as basic data for future development of design models for this combination of materials.

Seven columns were cast and tested under concentric loading; the variables studied included the diameter of steel bars for both longitudinal and lateral reinforcement. The dimensions of rectangular columns were: 100 mm x 200 mm x 740 mm high. Two columns were cast as full conventional concrete and full reactive powder concrete columns acted as control specimens. The remaining five were cast as hybrid columns having the conventional concrete at the core and surrounded by a 40 mm thickness of reactive powder concrete, with 1% micro steel fiber.

The combination of these two types of concrete into the hybrid concrete columns was very useful because it enhanced the ultimate capacity of the columns with respect to the conventional concrete in about 179% compared to the enhancement produced due to using the reactive powder concrete alone which was 203%, therefore, it was concluded that using this hybrid concrete combination in concrete industry would be more economical than the use of reactive powder concrete; moreover, based on the mode of failure observed, it would be safer to use the hybrid structural system because of the destructive type of failure for columns cast with conventional concrete. Increasing the diameter of the main reinforcement gave an average increase in the percentage of the failure load with respect to the conventional concrete column of about 179% compared to the increase in the diameter of the ties which gave an average increase of 185%; which leads to the conclusion that the effect of lateral reinforcement was more pronounced than the effect of the longitudinal reinforcement in hybrid columns, due to the increase in confinement produced by both the reactive powder concrete cover in the hybrid concrete columns and the ties represented by the lateral reinforcement.
Construction project planning using integration of crashing and concurrency techniques
Authors: Hady Haider Najy , AL-Kindi Luma Adnan , Mahmoud Mahmoud A.
Published: March 2020

Construction Project planning process is considered an essential area in the field of organization and implementation of projects, particularly those needing coordination, great effort and long implementation time. Moreover, project managers are focusing on achieving predetermined objectives. This paper aims to attain certain objectives; cost, time, and number of labourers, in a way that reaches the best satisfied results depending on the importance of each objective. A multi-objective model construction based on project planning in two techniques; crashing technique and concurrency is presented, additionally a new proposed mixed technique titled as Concurrency Partitioning with Crashing Techniques (CPCT). The proposed model is implemented on a Substation of Electrical Power for Transformation plant as a case for studying. The suggested mixed approach (CPCT) provides more desirable results with the multi-objective problem, where both project time and cost are decreased by 19.5% and 2.6%, respectively, while the total number of labourers is increased by 8.8%
Post-Blast Axial Capacity of CFRP Strengthened RC Columns
Authors: Kadhom Bessam , Almansour Husham , Saatcioglu Murat
Published: March 2020

An experimental investigation was carried out to evaluate the post-blast capacity of CFRP protected reinforced concrete (RC) columns. A total of five half-scale RC columns were tested under simulated blast pressures using a shock tube testing apparatus. Three columns were strengthened with CFRP laminates of two different lay-ups, while the other two columns were left unprotected to serve as control columns. Results of this study proved that CFRP protected RC columns have substantially higher blast resistant and post-blast axial capacity than as-built columns. CFRP protection laminates containing ±45° woven laminas showed the best performance with the most ductile response.
Experimental investigation on protection methods of Slurry Infiltrated Fiber Concrete in corrosive environments
Authors: Alrubaie Mays Fouad , Ahmed Salih Shakir , Alrazaq Abbas Waleed Abd
Published: March 2020

Many innovations had been achieved in concrete technology since the last decades to meet the ongoing needs for new types of concrete. Slurry infiltrated fiber concrete (SIFCON) is a special type of high strength high-performance steel fiber reinforced concrete. This new type of concrete characterized by its high strength and ductility is encouragingly used in many heavy duties applications. This research is carried out to study the efficiency of using different protection methods to protect SIFCON in chloride corrosive environments. Where, corrosion inhibitor admixture, mineral admixture (local metakaolin) and epoxy protective coating were used to provide either internal or external protection for SIFCON mixes. All mixes were evaluated for more than 390 days of exposing to chloride solution. Corrosion rates, half-cell potential, concrete resistivity, and chloride concentration tests were performed. The results indicated that all SIFCON mixes showed low to moderate corrosion rates. Also it was found that using of epoxy protective coating, corrosion inhibitor and mineral admixture can reduce the rate of corrosion as compared to unprotected mixes. The cyclic wetting and drying exposure to chloride environments was more aggressive to the specimens than the partial immersion in chloride.
Behaviour of square steel anchor plate in autoclaved aerated concrete block masonry
Authors: Verba V , Kholod P
Published: March 2020

This research was conducted to study the mechanical behaviour of square steel anchor plate mounted in thin-bed masonry, which was made of autoclaved aerated concrete (AAC) blocks of D400 density grade. The research objectives were to determine the failure mechanism in static push-in tests and suggest the best way of structural design for anchor plate in lightweight concrete masonry, and in particular to calculate its bearing capacity. As the behaviour of small size (40×40×5 mm) anchor plate used in the research depends on the mechanical properties of the masonry units as well as on the distance to edges and joints, these properties and factors were also studied. Low strength of aerated concrete under local compression was the main reason of failure for the investigated type of anchor plate and masonry. Graphical dependencies between anchor plate displacements and applied vertical load are presented. The highest and the lowest bearing capacities of anchor plate were observed when it was mounted in the middle of the block and at the joint, respectively. The design values of the vertical concentrated load resistance of the wall, NRdc, calculated according to EN 1996-1-1, are in good agreement with experimental failure loads.
Sustainable metakaolin based pervious geopolymer concrete with recycled concrete aggregate
Authors: Frayyeh Qais J , Khalil Wasan I , Abed Haider T
Published: March 2020

Production of Portland cement causes many environmental problems. Whereby, about seven percent by the gross weight of CO2 emissions resulted from cement production factories. Therefore, the usage of geopolymer binder, to produce pervious concrete, instead of Portland cement considers the one solution towards conserving the environment by reducing emission of carbon dioxide. In this paper, we investigate the production of local metakaolin (MK) as a geopolymer binder to produce Pervious Geopolymer Concretes (PGC). Also, the inclusion of recycled construction materials wastes as aggregates (RA) for production of (PGCs) was studied. PGC was produced from local metakaolin (MK), sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution, and recycled concrete (RC) as a volumetric partial replacement from the natural coarse aggregate (NA). All PGC specimens cured at a temperature of 50°C for five hours after 24 hours from casting and tested after 28 days. Compressive strength, total void content, splitting tensile strength, flexural strength, dry density and coefficient of water permeability for the PGCs were investigated. The results of mechanical properties were ranged from (12.23, 1.81 and 2.5) to (9.86, 1.3 and 1.95) MPa for compressive, splitting tensile and flexural strengths, respectively. The results articulate that the recycled concrete (RC) can be used as recycled coarse aggregates with a partial replacement for producing PGC with acceptable properties.
Experimental evaluation of stress-strain relations in compression for Pozzolime concrete
Authors: al-Attar T S , Abdulqader S S , Rashid R M
Published: March 2020

World cement demand and production are increasing. This is associated with a significant increase in the cement industry’s absolute energy use and CO2 emissions. With the increasing awareness about the environment, waste materials and by-products utilization, it has become an attractive alternative to obtain new solutions for a sustainable development. Pozzolime concrete is a promising binder alternative to Portland cement, which is forming compounds possessing cementitious properties. In this study the Pozzolime was produced via a mixture of hydrated lime and Pozzolana (Silica fume or fly ash). As a relatively new material, many engineering properties of Pozzolime concrete are still undetermined. Therefore, the modulus of elasticity and stress-strain behavior in compression have been studied experimentally. Two mixes were studied considering the compressive strength levels, 25 and 40, and for ages of 14, 28 and 56 days. The results obtained from experimental data were analyzed for stress-strain relations, compressive strength, fc, strain associated with peak compressive stress, εp, linearity of the stress-strain curve, modulus of elasticity of Pozzolime Concrete. An empirical equation is proposed for predicting stress-strain characteristics of Pozzolime concrete based on the test results by using regression analysis.
Some properties of green concrete with glass and plastic wastes
Authors: Khalil W I , Al Obeidy N F
Published: March 2020

This study focusses on the flexural strength, flexural toughness, thermal conductivity, and failure modes under flexural for concrete containing 15% glass powder waste as partial replacement of cement by weight and 25, 50, 75, 100% plastic waste as volumetric replacement of natural coarse aggregate at 60 days.

The results show an increase in flexural strength and thermal conductivity when 15% glass powder waste was used, while there is a significant decrease with the use of plastic waste relative to reference specimens (without wastes). It can be observed a significant increase in total flexural energy when the content of plastic waste coarse aggregate is increased.

The incorporation of plastic waste aggregate in concrete with 15% glass powder changes the failure behavior of concrete specimens from a brittle to a more ductile failure. The failure in reference concrete specimens without coarse plastic waste aggregate occurs in matrix, through coarse aggregate, and around the aggregates in interfacial transition zone (ITZ). On the other hand, in concrete containing HDPE (high density polyethylene) plastic waste aggregate with 15% glass powder, the failure occurs mainly around plastic particles.
Evaluation of factors influencing the compressive strength of Portland cement statistically
Authors: Salih M A , Aldikheeli M R , Shaalan k A
Published: March 2020

One of the most effective parameters that influence the performance of concrete is the compressive strength of cement. The chemical composition and the physical properties of Portland cement (PC) can be greatly affected the compressive strength of it. So the aim of this study is to make a statistical analysis for the effect of many factors on (3, 7, 28, and 60 day) compressive strength test results. The factors investigated include the main four compounds of cement (C2S, C3S, C3A and C4AF) in addition to (CaO, MgO, SO3, loss on ignition (LOI), insoluble residue (IR) lime saturation factor (LSF), silica modulus (SM) and alumina ratio (AR)). Furthermore fineness, unsoundness and setting time of cement were also studied. To attain the aim of the present work a statistical program “Statistica” was used for the analysis. It was found that (C3S, C3A and C4AF) compounds has a good correlation with compressive strength, while (C2S, CaO, MgO and SO3) has a negative effect especially at age of 3 days, considering that (C2S and SO3) effect became positive at 7 day age onward. The effect of (LSF and fineness) was positive on compressive strength and the effect of (LOI, IR, SM, AR, unsoundness, fineness, IST, FST) was negative.
Impact resistance and mechanical properties of High Strength Concrete containing local material
Authors: Shabbar Rana
Published: March 2020

High Strength Concrete (HSC) is an expression which is used to define a concrete with high performance and strength exceeds 40 MPa. The high elasticity or strength and low shrinkage and permeability are considered the main properties of the HSC. The aim of this study is to investigate the effect of High Reactivity Metakaolin (HRM) and/or Silica Fume (SF) on the properties of HSC. Local material “Kaolin Clay” was prepared as a pozzolana and the final product confirms the physical and chemical requirements of natural pozzolana. Eight mixes of the HSC with partial cement were replaced by HRM and SF (either individually or in combination). The effect of HRM and SF on the compressive, flexural strength, splitting tensile, impact resistance and modulus of elasticity of the HSC were studied. The results showed that the mix with 10% of HRM provided higher effect on the mechanical properties and impact resistance of the HSC. In addition, the HSC with the combined of 5% SF and 5% HRM
exhibited greater performance and more economic than other mixes.
Flexural Behavior of Square Ferrocement Panels Enhanced with Recycled Tires Sim Strengthened by CFRP
Authors: Jomaah Muyasser M. , Ismael Zeyad T. , Majeed Marwah Q. , Hameed Banan M
Published: March 2020

This paper presents an experimental algorithm with the results of using steel fibers in ferrocement panels, which were recovered from tires scrap. Waste steel fibers were cut with the same geometrical characteristics of normal steel fibers and were used in the panels at different layers. To have a reference ferrocement specimen, a plain mixture without fibers and mixtures containing a ratio of recycled steel fiber were also prepared. Some mechanical tests, such as compressive strength, splitting tensile strength and flexural strength were determined. Furthermore, load deflection behaviors for 24 panels specimens were carried out under patch load. Test results show that the recycled steel fibers layers recovered from scrap tires affected the mechanical behavior of ferrrocement panels that are similar to the number of wire mesh layers. Depending on the distribution of R.S.F layers and wire mesh layers, the load-deflection curves were found. A comparison between these curves indicates that the R.S.F can reduce the deflection of panels, and increasing the number of wire mesh layers can increase the ability to bear stresses for panels. Rehabilitation with carbon fiber strips CFRP carried out with three forms (box network, inclined with diagonal, parallel to the diagonal and mix of diagonal and box network). The curves show that the rehabilitation with a parallel form to the diameter of the sample is a better treatment, which is characterized by resistance to stresses rather than other forms. We estimate that the recycled steel fibers increase the flexural strength and tensile strength, and 10% is the optimal ratio for increasing the flexural strength and tensile, increasing the number of wire mesh layers increases the ability to bear stresses of the panels. Recycled steel fibers can cause reduction in the deflection of ferrocement panels and can give the same bearing strength proximity (or less) to the panel containing the same number of wire mesh layers.
Some properties of sustainable concrete with mixed plastic waste aggregate
Authors: Khalil W I , Mahdi H M
Published: March 2020

The objective of this research is to study the influence of using waste material (irregular plastic mix) on and properties and behavior of concrete. Various coarse plastic aggregate of 15, 25 and 45 % as replacement to coarse natural aggregate by volume were carried out. The experimental program consists of many tests, compressive strength, splitting tensile strength, flexural strength, thermal conductivity, absorption of water and density. The results demonstrate that the increase of plastic waste content decreases the compressive strength; while the workability slightly improves. The dry density of the concrete decreases with the increase of the plastic waste aggregate, satisfied structural lightweight concrete can be produced with 45% replacement of plastic waste aggregate. Also, a major improvement in the thermal conductivity was observed, while the absorption of water growths as the plastic waste content increased.
Strength and thermal conductivity of geopolymer pervious concrete made from artificial lightweight aggregate
Authors: Nasser I F , Khalil W I , Abbas WA
Published: March 2020

In this paper, geopolymer lightweight aggregate pervious concrete (GPLWAPC) was studied. It utilized two ratios of blending, which are 1:4 and 1:5 (fly ash: local artificial coarse aggregate). The rough aggregates utilized were graded as well as made of single size. An optimal ratio of aggregates content was achieved via the technique of trial and error. The fly ash (FA) that was used was low calcium, while the alkali activating element represents sodium hydroxide (NaOH) along with sodium silicate (Na2SiO3) with proportion of 1:2.5. Mixture was made with alkaline liquid to fly ash 0.4 proportion, NaOH concentration of 16 molarity was used. The artificial graded coarse aggregate to fly ash proportion of 1:4 shows the highest compressive strength with 5.2 MPa at 7 days with density of 1340 kg/m3. Many experimental investigations on GPLWAPC were investigated; workability and the strengths of compressive and splitting tensile, at the age of 7, 28 and 56 day, were studied. Moreover, thermal conductivity and scanning electronic microscopy were examined at 28 day age for the same mixture.
Study the effect of using different quenching mediums on erosive wear behavior of high chromium white cast iron
Authors: Betti Zainab Azeez , Ataiwi A. H.
Published: March 2020

In order to a accomplish economically good martempering process, it is required to find a cheaper and more available alternative quenching medium for the ordinary nitrate mixture used in this process. A high chromium white cast iron, which is generally used as mill liners in mining, crushing, and cement plants, is subjected to severe conditions of wear/impact. These conditions lead to failure and reduction in part life as well as increase in the cost of repairs, therefore, it is important to enhance its mechanical properties. The effect of different quenching mediums used in martempering treatment on the erosive wear, microstructure and mechanical properties of this cast iron was studied. In this study, two types of quenching mediums were used: Nitrite mixture (50% NaNO3 + 50 % KNO3) and Hydroxide mixture (50% NaOH : 50% KOH). The specimens were austenetized at 950°C for 1 hr then the first group was quenched in nitrate mixture and the other was quenched in hydroxide mixture, both at about 350°C, for (1/2, 2, 4, 6, 8) hrs. It was concluded that the two mediums enhance erosive wear resistance, but the nitrate mixture show the best erosive wear results among the other treatments, especially at martempering about 350°C for 4 hrs.
Mechanical and durability properties of cementitious brick containing Nano Ferrite
Authors: Rawdhan Rasha R. , Salman Ghaed K. , Ismail Muaid M.
Published: March 2020

This research investigates the influence of addition of Nano materials (Nano ferrite) on the physical and mechanical properties of the cementitious brick, by adding 1, 2, 3% of Nano ferrite by weight of cement. Bearing strength tests at RT and exposure to 100, 200, 300°C temperature after 4 hour, Bulk density and water absorption of resulting bricks were tested. Ni-Zn-Mg-ferrite nanoparticles were prepared using citrate auto combustion method using the X-Ray Diffraction (XRD) to characterize the prepared sample where found the particle size is (49.6 nm) with good crystalline structure. The results show that possibility to synthesize nanoparticles, the optimum content of the Nano ferrite was 2% that produces the ultimate increase in the bearing strength and improvement in physical properties. The mechanical test results showed a tendency to lose strength at high temperature. It was found that a decrease in the water absorption from 4.913 to 3.273 wt % occurred at 3% of Nano ferrite.
Improvement of polyurethane thermal insulation materials by using corn stalk
Authors: Karapinar I Sanri
Published: March 2020

The heat loss during the heating of buildings constitutes about 40% of the greenhouse gas emission that causes global warming. Thus, in order to decrease the energy for heating buildings, various kinds of insulation systems and materials have been used. In this study, by using corn stalks, a polyurethane insulation material was produced. The unit weight, ultrasonic pulse velocity and thermal conductivity coefficients of the produced material were determined. The thermal conductivity coefficient of this composite material was found to be 0.042. The insulation values obtained were in an acceptable range, i.e. they satisfy the Turkish Standard TS 805 EN 60155. Thus, with the zero-waste objective, this study presents an alternative construction material containing a certain type of waste material, also avoiding the environmental problems it causes.
Field study of the effect of jet grouting parameters on strength based on tensile and unconfined compressive strength
Authors: AL-Kinani Ali M , Ahmed Mahmood D
Published: March 2020

The improvement of the mechanical soil characteristics of jet grouting technique is very attractive. The jet grouted soil cement columns in soft is a complicated issue because it depends on a number of factors such as, soil nature, mixture, influence among soil and grouting materials, jetting force of nozzle, jet grouting and water flow rate, rotation and lifting speed. This paper discusses the estimation of shear strength parameters of soil-cement column (soilcrete) in soft clayey soil based on the relationships between the unconfined compressive and split tensile strength for the soilcrete and the effect of the jet grouting and water pressure in the values of cohesion and internal friction. For this reason, theoretical and field work models have been developed. The relation between split tensile and unconfined compressive strength results were used to draw a Mohr’s circle and failure enveloped to define the shear strength parameters of soilcrete. According to that, the results indicate that the resistance of the jet grout columns increases by increasing the nominal resistance of the grouting material (cement), water and jet grouting pressure. The shear resistance variables are increased by increasing the unconfined compressive and tensile strength of the jetting column. The value of the unconfined compressive strength ranges from (2.78-5.52 MPa). While the internal friction angle varies from 38° to 44°. On the other hand, the tensile strength is increased by increasing the unconfined compressive strength and ranges from (0.66-1.02 MPa).