Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Self


Behavior of Tapered Self-Compacting Reinforced Concrete Beams Strengthened by CFRP

T.S. al-Attar; S.S. Abdulqader; S.K. Ibrahim

Engineering and Technology Journal, 2017, Volume 35, Issue 3, Pages 197-203

This study presents an experimental investigation on the behavior of fourteen reinforced self-compacting concrete tapered beams with or without strengthening. The strengthening was applied by using carbon fiber reinforced polymer (CFRP) to beams with simply supported span and subjected to two points loading. Those beams have an overall length of 2000 mm, a width of 150 mm and a height of 250 mm at supports (hs) and a mid-span depth (hm) varies between 150 mm and 200 mm and with different strengthening scheme, they are investigated to evaluate the behavior at experimental test and to study the effect of the parameters which include haunch angle α, shear-span to effective depth ratio a/d and strengthening strips number and locations on beams behavior. The experimental results show that decreasing the value of haunch angle α increased the load capacity by about 56% and decreased the corresponding deflection while when tapered beams are strengthened by CFRP the ultimate load is increased up to 39% with decrease of deflection. On the other hand, increasing a/d ratio leads to a decrement in load capacity and increment in deflection.

Interaction between learners within Self-Organized Learning Environments-Spaces of Architectural Engineering Department Case study

A.M.H. Al-Moqaram; R.R.F. Al-Amara

Engineering and Technology Journal, 2017, Volume 35, Issue 0, Pages 114-132

Self-organized learning environment considered as a contemporary concept that directed toward
transform the education system from traditional environment architecture to scalable
environment which could be formed by students and teachers. Descriptions components of this
environment are varied in previous studies, constraining some time on intellectual side or on
physical side or on behavioral side. Most of them describe teaching approaches between
traditional and contemporary one, but there is lake in determining the nature on interaction
between learner and teacher within specific physical learning spaces. The research problem is
"Lack of knowledge about interactive relationship between self-organized learning
environments components-intellectual, physical and social- and in particular physical role
in promoting interaction between the learners within these environments". Research
methodology consists of three steps. first establish theoretical framework about characteristics of
self-organized learning environment and identify the items if interaction between learner .Second
applied these items on case study consist of two different learning environments in department of
architecture in technological university, traditional and non-traditional and using questioners
methods, third, analyze finding and draw conclusions .main conclude is self-organized learning
environment is a scalable interactive environment compering with traditional one according to
learning approaches that applied in them.

High Biometric Recognition Based on Histogram and Semi-discrete Matrix Decomposition via Neural Network

Ekbal Hussein Ali; Sameir A. Azeiz; Suad Ali Eissa

Engineering and Technology Journal, 2016, Volume 34, Issue 12, Pages 2239-2248

Iris recognition is regarded as the most reliable and accurate biometric identification system available highly protected and stable.Iris situating is the main focus in the procedure of iris recognition and verifies the precision of identification. In this work, a new algorithmfor iris localization is suggested based on the median filter and the histogram to determine an automated global threshold and the pupil centre. An algebraic based on semi-discrete matrix decomposition SDD is used to extract iris feature from iris image that decrease the difficultyininput layered neural network,thesizes of input patterns are enhanced. The iris recognition is developed by a neural network with differential adaptive learning rate to identify the iris features. This method is simple,effective and high speed recognition. The system is implemented by using Matlab. Experimental outcomes indicate that the suggested algorithm gives the accuracy of 100 % with time equal 1.4 sec is best than other methods for Daugman and Wildes.

Effect of Steel Fibers, Polypropylene Fibers and/ or Nanosilica on Mechanical Properties of Self-Consolidating Concrete

Iqbal N. Gorgis; Maan S. Hassan; Rana T. Abdulkareem

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 527-538

This research concerned studying the combined effect of using nano-silica and/ or hybrid fibers on key mechanical properties of self-consolidating concrete SCC. A comprehensive experimental work has been carried out, using steel fiber (SF) with volume fraction (0, 0.5% and 1.5%), polypropylene fiber (PPF) (0%, 0.05% and 0.15%) and SiO2 nanoparticles (0%, 2% and 4%) by weight of powdered material (silica fume- Sf ) with constant w/c ratio (0.48) to produce eleven different mixtures and tested at different ages (7, 28 and 90 days).
Results showed that adding fibers adversely affect SCC workability and thus more dosage of super plasticizer (SP) should be added to stay within the standard limits. comparable to conventional concretes, the presence of steel fibers with SCC provide slight increase in compressive strength at 28 days, (up to 11%), while significant enhancement in tensile properties were observed (up to 24% and 32% for splitting and flexural strength respectively). Polypropylene or hybrid fibers however, provide lower enhancement compared with steel fibers. In contrast, implementation of nanosilica leads to significant improvement in concrete strengths particularly at 4% dosage. Combined effect of 4% nanosilica and 1.5% of steel fibers provide the superior hardening effect on the flexural performance compared with softening effect provided by other added dosages. Scanning Electron Micrograph (SEM) images confirm the matrix densification effect due to nanosilica adding. Flexural strength of SCCs without nanosilica was generally higher than splitting testing results. This fact does not change even with the presence of nanosilica and/ or fibers.

Behavior and Strength of Concentrically Loaded Flat Slabs Using Self-Compacting High Strength Concrete With and Without Openings with Steam Curing

Esraa Khudhair Mohsin Abuzaid

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 648-663

Openings in slabs are usually required for plumbing, fire protection pipes, and ventilation ducts and air conditioning.
This study presents an experimental investigation on the influence of openings on the punching shear strength of high reinforced concrete flat plates. Five models of slab-column connection of (1000 x 1000 x 70mm) simply supported along the four edges are tested. The slabs are loaded concentrically by a central stub column. The main variables studied are the size(100x100mm and 200x100mm)and location(at 35 mm , at 135mm from center of slab and at the corner of slab) of the openings and used steam curing method.
Experimental results are recorded and studied at various stages of loading, deflection at the center of the slab, at distance (150mm) from the center of the slab in two directions and at the edge of the tested slab out of support. First cracking load and ultimate load capacity are also recorded.

Design and Development Dynamic Functional Models of Radio Systems by Using the MATLAB System

Saad Z. Sekhi

Engineering and Technology Journal, 2016, Volume 34, Issue 2, Pages 322-333

In this study, we have presented brief theoretical information regarding the design of dynamic functional models of radio systems and practical recommendations for their development and investigation in the MATLAB system. The paper mainly concentrates on three points, as follows: 1. Development of a dynamic functional model filters shaping to obtain the Gaussian random processes with given correlation properties using the MATLAB environment. 2. A development study of a dynamic model rectangular pulse detector against the background self-noise.

Fresh and Hardened Properties of Steel Fiber-Reinforced Self-Consolidating Concrete

Maan S. Hassan; Iqpal N. Gorgis; Aymn H. Ali

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 1213-1225

The main aim of this research is to study the effect of using hooked end steel fiber on the fresh and hardened properties of self-consolidating concrete. The experimental work includes two stages. First stage involved conducting several trial mixes and then choosing the one that conform tothe international standards in terms of fresh properties. Second stage concerned on the compressive, flexural tensile and splitting tensile strengths evaluationof the selected mixes, at 28 and 90 days.Four concrete mixes were obtained and evaluated. They were similar in mix proportions and differ only in volume fractions of steel fibers incorporated: 0%, 0.5%, 1%, and 1.5%.
Results showed that adding hooked steel fibers adversely affect SCC workability and thus more dosage of SP should be added to stay within the standard limits. Similar to conventional HPC, the presence of steel fibers with SCC provide slight increase in compressive strength at 28 days, (up to 11%), while significant enhancement in tensile properties were observed (up to 68% and 80% for splitting and flexural strength respectively). Flexural strength (i.e. modulus of rapture) was generally still higher than splitting testing results in a decreasing order. This order is still applicable in SCC even with the presence of steel fibers.

Some Properties of Self Compacting Concrete by Using Different Types of Local Rocks as a Coarse Aggregate

Ahmed H. Abed; Zena K. Abbas Al-Anbori; Firas Feisal

Engineering and Technology Journal, 2015, Volume 33, Issue 4, Pages 788-801

Self-Compacting Concrete (SCC) is a new type of concrete that possesses the property of high flow ability, passing ability and stability.This research aims to investigate the properties of the SCC produced by using locally available materials and to study the effect of using local rocks as a coarse aggregate such as quartzite, dolomite and limestone with two replacement ratio 50% and 100% of traditional coarse aggregate (gravel).
The SCC mixes prepared with full and 50% replacement of quartzite gives higher compressive strength, splitting strength, flexural strength and ultrasonic pulse velocity compared with mix that contained gravel with percentage of enhancement (11.9%), (9.5%), (12.4%) and (2%); respectively for fully replacement at 28 day.On the other hand, it has been noticed that the concretes prepared with full and 50% replacement of dolomite give lower compressive strength, splitting strength, flexural strength and ultrasonic pulse velocity compared with mix that contained gravel with percentage of detraction (10.3%), (4.8%), (5.9%) and (1.2%); respectively for fully replacement. Also, for both full and 50% replacement; limestone exhibits the same behavior of dolomite but with larger percentages of detraction which are (24.2%), (33.3%), (27.1%) and (3.6%).

Effect of Plastic Optical Fiber on Some Properties of Translucent Concrete

Shakir Ahmed Salih; Hasan Hamodi Joni; Safaa Adnan Mohamed

Engineering and Technology Journal, 2014, Volume 32, Issue 12, Pages 2846-2861

Translucent concrete is a building material with light-transmitting properties, due to embedded light optical elements in its mixture; and has the advantage of energy saving in addition to providing nice view to a building. The present study investigated the use and properties of translucent concrete mixture as a construction material with light admittance. The work includes two parts: in the first part many trail mixes are designed and tested to produce self-compact mortar (SCM).Then the obtained mixture is used to prepare a new type of translucent composites with plastic optical fibers POF embedded in the SCM mixture. The second part investigates some of the mechanical properties of translucent concrete by using three concentration of (POF) and three different diameters. The tested results indicate that it is possible to use SCM to produce translucent concrete contain plastic optical fiber (POF) with compressive strength between 31.1 to 40.4 MPa and flexural strength between 5.89 to 8.12MPa for different POF volume fraction content and diameter size at 28 days age.

Direct Shear Behavior of Carbon Fiber Reinforced Self- Compacting Concrete

Kaiss F. Sarsam; Tareq S. Al-Attar; Ghzwan Ghanim Jumah

Engineering and Technology Journal, 2014, Volume 32, Issue 10, Pages 2491-2513

This paperrepresents an experimental and statistical investigation for the behavior of connectionpoints produced by using self-compacting concrete and subjected to direct shear. The investigation also includes the effect of carbon fiber inclusion as reinforcement on self-compacting concrete (SCC) behavior in direct shear.
This study gives results of sixteen push-off or direct shear specimens in four groups. Variations include volume fraction for carbon fiber (V_f= 0.00, 0.50, 0.75 and 1.00) % for every percentage change in the steel reinforcement. The steel reinforcement parameter ρ_vf f_y values are (0.00, 2.66, 5.33 and 7.99) MPa(where ρ_vf varies from 0.00 to 0.0173 and f_y=585.7MPa) . The main material properties studied include compressive strength, splitting tensile strength and modulus of rupture. Measurements of deformations were made throughout testing of shear specimens.
The dimension of the shear plane in the push-off specimenswas 170x185 mm. The shear reinforcement was normal to the shear plane. Specimens were cast by using SCC which is a type of high performance concreteand reinforced with carbon fiber.
This work aims to investigate the direct shear behavior of SCC with or without carbon fiber at constant water to cementitious materials ratio of 0.3 by weight. It is found that using carbon fiber increased the direct shear strength. However, carbon fiber alone (without reinforcement) leads to brittle failure. In contrast, adding rebars leads to higher strain and more ductile behavior-increased shear capacity is obtained when higher steel quantity is used. The aim of adding carbon fibers was the increase of the horizontal strain (displacement). It was found that the optimum percentage of volume fraction was 0.75 % for fresh and hardened concrete.
In addition, the effects of carbon fiber on compressive strength of SCC lead to a drop in compressive strength (f_c^') compared with reference specimens. This drop in f_c^' was 2.39, 8.38 and 13.58% for V_f=0.50, 0.75 and 1.00%, respectively. In contrast, the splitting tensile strength increased by 3.34, 31.2 and 18.2 as compared with the cylinder strength without carbon fibers atV_f equal to0.50, 0.75 and 1.00% respectively. The modulus of rupture increased by [11.9, 21.99 and 13.83%] as compared with SCC without carbon fibers at〖 V〗_f equal to 0.50, 0.75 and 1.00% respectively.
Based on push-off tests results for this work and those available in the literature, two statisticalmodels have been established using regression analysis. Four variables f_c^',f_ct,ρ_vf f_y and V_f, were included in these models. Both models showed good representation according to their coefficients of variation (COV)values. Verification of the models were done by using 273 observations from literature and the present work.

Grain Size Distribution of the Self-Filtration Layer between the Base Soil and the Filter

Yousif A. H. Dallo; Yuan Wang

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 453-464

Some studies suggested a model to determine the grain size distribution GSD curve of the self-filtration layer that is formed at the base soil-filter interface. From these GSD curves the effectiveness of the filters is assessed assuming that the internal stability of the self-filtration layer reflects the effectiveness of the filter. In this paper a critical discussion to that method is presented. Also some essential modifications for the method are suggested. Finally, in disagreement with that method the applicability of usage of the GSD curve of the self-filtration layer to predict the effectiveness of the filter is found to be unreliable.

Ear Recognition by Using Self Organizing Feature Map

Suad K. Mohammad

Engineering and Technology Journal, 2013, Volume 31, Issue 10, Pages 2000-2013

A wide variety of systems requires reliable personal recognition schemes to either confirm or determine the identity of an individual requesting their services. The purpose of such schemes is to ensure that the rendered services are accessed only by a legitimate user and no one else.
The aim of the work presented within this paper is to develop an optimum image compression system using haar wavelet transform and a neural network. In this paper we have developed and illustrated a recognition system for human ears using a Kohonen self-organizing map (SOM) or Self-Organizing Feature Map (SOFM) based retrieval system. SOM has good feature extracting property due to its topological ordering. The ear Analytics results for the 4 images of database reflect that the ear recognition using one of the neural network algorithms SOM for 4 persons. MATLAB programs were used to complete this work.

Experimental Evaluation of Effect of Flange Dimensions on Shear Behavior of NSC and SCC Double Tee Beams

Ali H. Aziz; Mohammad Zohair Yousif; Laye K. Salman

Engineering and Technology Journal, 2012, Volume 30, Issue 17, Pages 3039-3053

This study deals with, experimentally, the effect of flange dimensions on shear
behavior of normal strength concrete (NSC) and self-compacting concrete (SCC)
double Tee beams.
Twelve beam specimens as well as a series of control specimens are tested. The
beam specimens were divided into two groups (based on concrete type) and each
group are divided into five subgroups (based on flange dimensions).The webs
dimensions, beam depth, beam length, spacing between webs, longitudinal
(tension) reinforcement and transverse reinforcement (stirrups) were kept constant
in all beam specimens.
Experimental results showed that the ultimate capacity increased about (6%-
12) and (9%-20) when the flange width (dimensions) increased from (320mm) to
(450mm) for NSC and SCC respectively. Presence of large compression flange
lead to increase the stiffness of tested beams due to contribution of additional
concrete parts, and this leads to increase in carrying capacity.