P-value significance level test for high-performance steel fiber concrete (HPSFC)

Abdulhameed U. Abubakar,Tülin Akçaoğlu and Khaled Marar 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.5

Statistical analysis has found useful application in the design of experiments (DOE) especially optimization of concrete ingredients however, to be able to apply the concept properly using computer aided applications there has to be an upper and lower limits of responses fed to the system. In this study, the production of high-performance steel fiber concrete (HPSFC) at five different fiber addition levels by volume with two aspect ratios of 60 and 83 were studied under two curing methods completely dry cured (DC) and moist cured (MC) conditions. In other words, this study was carried out for those limits based on material properties available in North Cyprus. Specimens utilized were cubes 100 mm size casted and cured for 28 days and tested for compressive strength. Minitab 18 statistical software was utilized for the analysis of results at a 5 per cent level of significance. Experimentally, it was observed that, there was fluctuation in compressive strength results for the two aspect ratios and curing regimes. On the other hand P-value hypothesis evaluation of the response showed that at the stated level of significance, there was a statistically significant difference between dry and moist curing conditions. Upper and lower limit values were proposed for the response to be utilized in DOE for future studies based on these material properties. It was also suggested that for a narrow confidence interval and accuracy of the system, future study should increase the sample size.

Influence of pre-compression on crack propagation in steel fiber reinforced concrete

Abubakar, Abdulhameed U.,Akcaoglu, Tulin Techno-Press 2021 Advances in concrete construction Vol.11 No.3

In this study, a new understanding is presented on the microcracking behavior of high strength concrete (HSC) with steel fiber addition having prior compressive loading history. Microcracking behavior at critical stress (σcr) region, using seven fiber addition volume of 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, and 2.0% was evaluated, at two aspect ratios (60 and 75). The specimens were loaded up to a specified compressive stress levels (0.70fc-0.96fc), and subsequently subjected to split tensile tests. This was followed by microscopic analyses afterwards. Four compressive stress levels as percentage of fc were selected according to the linearity end point based on stress-time (σ-t) diagram under uniaxial compression. It was seen that pre-compression has an effect on the linearity end point as well as fiber addition where it lies within 85-91% of fc. Tensile strength gain was observed in some cases with respect to the 'maiden' tensile strength as oppose to tensile strength loss due to the fiber addition with teething effect. Aggregate cracking was the dominant failure mode instead of bond cracks due to improved matrix quality. The presence of the steel fiber improved the extensive failure pattern of cracks where it changes from 'macrocracks' to a branched network of microcracks especially at higher fiber dosages. The applied pre-compression resulted in hardening effect, but the cracking process is similar to that in concrete without fiber addition.

The Extent of Ordinary Classrooms Teachers' Knowledge and Perception of Attention Deficit Hyperactivity Disorder (ADHD)

Talafha, Abdulhameed Hasan International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.11

The present study aimed to investigate the extent to which ordinary classrooms teachers are informed are familiar with Attention Deficit Hyperactivity Disorder 'ADHD'. The researcher adopted the descriptive approach. The sample of the study consisted of (89) male and female teachers who teach students from grade (1) to grade (6) at public primary schools in Northern Mazar Directorate of Education in Jordan. A questionnaire was employed as the primary tool for collecting the data. The findings of the current study indicated an average level of knowledge of ordinary classroom teachers about ADHD. The findings also indicated that there were no statistically significant differences in the extent of ordinary classroom teachers' knowledge of ADHD due to the variables (gender, qualification, professional experience, grade level being taught).

The Extent of Ordinary Classrooms Teachers' Knowledge and Perception of Attention Deficit Hyperactivity Disorder (ADHD)

Talafha, Abdulhameed Hasan International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.10

The present study aimed to investigate the extent to which ordinary classrooms teachers are informed are familiar with Attention Deficit Hyperactivity Disorder 'ADHD'. The researcher adopted the descriptive approach. The sample of the study consisted of (89) male and female teachers who teach students from grade (1) to grade (6) at public primary schools in Northern Mazar Directorate of Education in Jordan. A questionnaire was employed as the primary tool for collecting the data. The findings of the current study indicated an average level of knowledge of ordinary classroom teachers about ADHD. The findings also indicated that there were no statistically significant differences in the extent of ordinary classroom teachers' knowledge of ADHD due to the variables (gender, qualification, professional experience, grade level being taught).

Concha bullosa, nasal septal deviation, and their impacts on maxillary sinus volume among Emirati people: A cone-beam computed tomography study

Al-Rawi, Natheer H,Uthman, Asmaa T,Abdulhameed, Elaf,Al Nuaimi, Ahmed S,Seraj, Zahra Korean Academy of Oral and Maxillofacial Radiology 2019 Imaging Science in Dentistry Vol.49 No.1

Purpose: To determine the prevalence of concha bullosa (CB) and nasal septal deviation (NSD) and their impact on maxillary sinus volume (MSV). Materials and Methods: Cone-beam computed tomographic (CBCT) images of 106 Emirati people were used in this study. The direction and angle of septal deviation were calculated. The presence of CB, which could be unilateral, contralateral, or bilateral in relation to the direction of NSD, was also recorded. MSV was measured using reconstructed Digital Imaging and Communication in Medicine images on Dolphin 3D imaging software version 11.8 premium (Dolphin Imaging, Chatsworth, CA, USA). P values<0.05 were considered to indicate statistical significance. Results: CB was detected in 37.7% of the sample; 20.7% of the sample showed single unilateral CB and 16.6% had single bilateral CB. NSD was seen in 74.5% of the sample. In the participants with CB, 45.5% showed mild deviation, 34.4% showed moderate deviation, and only 12.5% showed severe septal deviation. CB, but not NSD, was associated with significantly higher MSV on the affected side (P=0.001). Conclusion: Although NSD was observed in more than two-thirds of the sample and CB was present in more than one-third of the sample, only CB had a significant impact on MSV.

Predicting the Greenhouse Air Humidity Using Artificial Neural Network Model Based on Principal Components Analysis

오우라비압둘하메드바바툰데,이종원,메쓰캄카남즈사니카닐란가니자야세카라,이현우,Owolabi, Abdulhameed B.,Lee, Jong W,Jayasekara, Shanika N.,Lee, Hyun W. The Korean Society of Agricultural Engineers 2017 한국농공학회논문집 Vol.59 No.5

A model was developed using Artificial Neural Networks (ANNs) based on Principal Component Analysis (PCA), to accurately predict the air humidity inside an experimental greenhouse located in Daegu (latitude $35.53^{\circ}N$, longitude $128.36^{\circ}E$, and altitude 48 m), South Korea. The weather parameters, air temperature, relative humidity, solar radiation, and carbon dioxide inside and outside the greenhouse were monitored and measured by mounted sensors. Through the PCA of the data samples, three main components were used as the input data, and the measured inside humidity was used as the output data for the ALYUDA forecaster software of the ANN model. The Nash-Sutcliff Model Efficiency Coefficient (NSE) was used to analyze the difference between the experimental and the simulated results, in order to determine the predictive power of the ANN software. The results obtained revealed the variables that affect the inside air humidity through a sensitivity analysis graph. The measured humidity agreed well with the predicted humidity, which signifies that the model has a very high accuracy and can be used for predictions based on the computed $R^2$ and NSE values for the training and validation samples.

Repair of Pre-cracked Reinforced Concrete (RC) Beams with Openings Strengthened Using FRP Sheets Under Sustained Load

Osman, Bashir H.,Wu, Erjun,Ji, Bohai,Abdulhameed, Suhaib S. Korea Concrete Institute 2017 International Journal of Concrete Structures and M Vol.11 No.1

Strengthening reinforced concrete (RC) beams with openings by using aramid fiber reinforcement polymers (AFRP) on the beams' surfaces offers a useful solution for upgrading concrete structures to carry heavy loads. This paper presents a repairing technique of the AFRP sheets that effectively strengthens RC beams, controls both the failure modes and the stress distribution around the beam chords and enhances the serviceability (deflection produced under working loads be sufficiently small and cracking be controlled) of pre-cracked RC beams with openings. To investigate the possible damage that was caused by the service load and to simulate the structure behavior in the site, a comprehensive experimental study was performed. Two unstrengthened control beams, four beams that were pre-cracked before the application of the AFRP sheets and one beam that was strengthened without pre-cracking were tested. Cracking was first induced, followed by repair using various orientations of AFRP sheets, and then the beams were tested to failure. This load was kept constant during the strengthening process. The results show that both the preexisting damage level and the FRP orientation have a significant effect on strengthening effectiveness and failure mode. All of the strengthened specimens exhibited higher capacities with capacity enhancements ranging from 21.8 to 66.4%, and the crack width reduced by 25.6-82.7% at failure load compared to the control beam. Finally, the authors present a comparison between the experimental results and the predictions using the ACI 440.2R-08 guidelines.

Numerical desirability function for adsorption of methylene blue dye by sulfonated pomegranate peel biochar: Modeling, kinetic, isotherm, thermodynamic, and mechanism study

Ali H. Jawad,Ahmed Saud Abdulhameed,M. A. K. M. Hanafiah,Zeid A. AlOthman,Mohammad Rizwan Khan,S. N. Surip 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

Sulfonated pomegranate (Punica granatum) peel biochar (SPPBC) was developed via thermal activation with sulfuric acid (H2SO4) to act as a promising biochar material for the adsorptive removal of toxic cationic dye namely methylene blue (MB) dye from contaminated water. A Box-Behnken design (BBD) and numerical desirability function were adopted to optimize the input adsorption variables (SPPBC dosage, temperature, pH, and contact time). The maximum removal of the MB dye can be accomplished by simultaneous significant interaction between SPPBC dosage with solution pH, SPPBC dosage with time, SPPBC dosage with temperature, solution pH with time, and time with temperature. The numerical desirability function identified the highest MB dye removal (93.9%) can be achieved at the following optimum numerical adsorption conditions: SPPBC dosage 0.18 g, temperature 49 oC, pH 9.7, and time 4.3 h. Equilibrium data were well fitted to the Temkin and Langmuir isotherm models. The maximum recorded adsorption capacity of SPPBC for MB dye adsorption by using Langmuir isotherm model was 161.9mg/g. This research work reveals the possibility of converting lignocellulose pomegranate peel into a renewable and environmentfriendly biochar via a relatively fast acid-activation process with the great potential to be promising adsorbent for removal of MB dye.

Shear Behavior of Reinforced Concrete (RC) Beams with Circular Web Openings without Additional Shear Reinforcement

Bashir H. Osman,Erjun Wu,Bohai Ji,Suhaib S. Abdulhameed 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.1

The introduction of an opening into a Reinforced Concrete (RC) beam leads to a reduction to both the beam’s stiffness and its overall structural capacity due to stress concentrations and local cracking around the opening. This paper uses both the experimental and finite element (FE) method to analyze the shear behavior of RC beams with opening. The shear span-to-depth ratios ( ), opening size, and opening location were considered as the main parameters. The beams were divided into three series according to the shear span-to-depth ratios. Three reinforced concrete beams without openings and one beam with openings were tested experimentally under two-point loading. These beams were considered as control beams so as to validate the FE model using ANSYS14.5 software. A total of 31 specimens were analyzed using ANSYS14.5 while considering the above mentioned parameters. Results showed that the openings located in a high shear region (the line connecting the load and support points) led to the early collapse of the beam. In addition, by comparing the experimental results with those of the non-linear FE analysis, it was concluded that both results were in accordance. An analytical equation for predicting the shear strength of RC beams with circular openings was then proposed, and the obtained results later compared with those from FE model. Furthermore, the developed FE models can serve as a numerical platform for performance predictions of RC beams with different web opening geometries.

Repair of Pre-cracked Reinforced Concrete (RC) Beams with Openings Strengthened Using FRP Sheets Under Sustained Load

Bashir H. Osman,Erjun Wu,Bohai Ji,Suhaib S. Abdulhameed 한국콘크리트학회 2017 International Journal of Concrete Structures and M Vol.11 No.1

Strengthening reinforced concrete (RC) beams with openings by using aramid fiber reinforcement polymers (AFRP) on the beams’ surfaces offers a useful solution for upgrading concrete structures to carry heavy loads. This paper presents a repairing technique of the AFRP sheets that effectively strengthens RC beams, controls both the failure modes and the stress distribution around the beam chords and enhances the serviceability (deflection produced under working loads be sufficiently small and cracking be controlled) of pre-cracked RC beams with openings. To investigate the possible damage that was caused by the service load and to simulate the structure behavior in the site, a comprehensive experimental study was performed. Two unstrengthened control beams, four beams that were pre-cracked before the application of the AFRP sheets and one beam that was strengthened without pre-cracking were tested. Cracking was first induced, followed by repair using various orientations of AFRP sheets, and then the beams were tested to failure. This load was kept constant during the strengthening process. The results show that both the preexisting damage level and the FRP orientation have a significant effect on strengthening effectiveness and failure mode. All of the strengthened specimens exhibited higher capacities with capacity enhancements ranging from 21.8 to 66.4%, and the crack width reduced by 25.6–82.7% at failure load compared to the control beam. Finally, the authors present a comparison between the experimental results and the predictions using the ACI 440.2R-08 guidelines.