Study of heavy fuel oil fly ash for use in concrete blocks and asphalt concrete mixes

Al-Osta, Mohammed A.,Baig, Mirza G.,Al-Malack, Muhammad H.,Al-Amoudi, Omar S. Baghabra Techno-Press 2016 Advances in concrete construction Vol.4 No.2

Use of heavy fuel fly ash (HFFA) (diesel and cracked fuel) for power generation in Saudi Arabia has generated and accumulated large quantities of HFFA as a byproduct. In this research, HFFA is studied with the emphasis on the utilization of this waste material in concrete blocks and asphalt concrete mixes. Two types of mixes, one with low and other with high cement content, were studied for concrete blocks. Different mixes having varying percentages of HFFA (0% to 25%), as cement/sand replacement or as an additive, were studied. The performance of concrete blocks is evaluated in terms of compressive strength, water absorption, durability and environmental concerns. The results showed that blocks cannot be cast if more than 15% HFFA is used; also there is a marginal reduction in the strength of all the mixes before and after being exposed to the sulfate solution for a period of ten months. HFFA is studied in asphalt concrete mixes in two ways, as an asphalt modifier (3&5%) and as a filler (50%) replacement, the results showed an improvement in stiffness and fatigue life of mixes. However, the stability and indirect tensile strength loss were found to be high as compared to the control mix due to moisture damage, indicating a need of using antistripping agents. On environmental concerns, it was found that most of the concerned elements are within acceptable limits also it is observed that lower concentration of barium is leached out with the higher HFFA concentrations, which indicates that HFFA may work as an adsorbent for this leaching element.

Durability performance of concrete containing Saudi natural pozzolans as supplementary cementitious material

Al-Amoudi, Omar S. Baghabra,Ahmad, Shamsad,Khan, Saad M.S.,Maslehuddin, Mohammed Techno-Press 2019 Advances in concrete construction Vol.8 No.2

This paper reports an experimental investigation conducted to evaluate the durability performance of concrete mixtures prepared utilizing blends of Type I Portland cement (OPC) and natural pozzolans (NPs) obtained from three different sources in Saudi Arabia. The control concrete mixture containing OPC alone as the binder and three concrete mixtures incorporating NPs were prepared keeping water/binder ratio of 0.4 (by weight), binder content of $370kg/m^3$, and fine/total aggregate ratio of 0.38 (by weight) invariant. The compressive strength and durability properties that included depth of water penetration, depth of carbonation, chloride diffusion coefficient, and resistance to reinforcement corrosion and sulfate attack were determined. Results of this study indicate that at all ages, the compressive strength of NP-admixed concrete mixtures was slightly less than that of the concrete containing OPC alone. However, the concrete mixtures containing NP exhibited lower depth of water penetration and chloride diffusion coefficient and more resistance to reinforcement corrosion and sulfate attack as compared to OPC. NP-admixed concrete showed relatively more depth of carbonation than OPC when subjected to accelerated carbonation. The results of this investigation indicates the viability of utilizing of Saudi natural pozzolans for improving the durability characteristics of concrete subjected to chloride and sulfate exposures.

Do Saudi Nurses in Primary Health Care Centres have Breast Cancer Knowledge to Promote Breast Cancer Awareness?

Yousuf, Shadia Abdullah,Al Amoudi, Samia Mohammed,Nicolas, Wafa,Banjar, Hasna Erfan,Salem, Safaa Mohammed Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Background: Breast cancer is one of the leading causes of death among cancer patients in Saudi Arabia. It is known that nurses play a key role in promoting breast cancer awareness among women in any society. Nurses in primary health care centres (PHCC) have more direct contact with general population. This study aimed to investigate nurse knowledge of breast cancer and practice of early screening in PHCC in Jeddah city. Methods: A cross-sectional study was conducted using a self-administered questionnaire to assess the general knowledge of breast cancer, risk factors, and practice of 210 PHCC nurses. Data were analysed using SPSS v.16. Results: The mean age of the PHCC Nurses was 36.9 (SD ${\pm}8.6$). Only 11% percent scored <50% of the total score for general epidemiological knowledge on breast cancer, about 35% scored <50% of the total score for breast cancer risk factors. Sixty seven percent scored >75% of the total score on breast cancer signs. Majority of nurses 62.8% practiced BSE, but only 4% practiced regularly every month. Some 28% practiced once per year. About 81% of the nurses had not had a clinical breast examination and only 14% had had a mammography. The results of the study failed to show any correlation between the knowledge scores with age, education, year of experience, family history of BC and marital status of the nurses. Conclusion:The results from the study reflect that there is a need to provide continuing nursing education programmes for PHCC nurses to improve their breast cancer knowledge and practice.

Predicting compressive strength of bended cement concrete with ANNs

Uneb Gazder,Omar Saeed Baghabara Al-Amoudi,Saad Muhammad Saad Khan,Mohammad Maslehuddin 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.6

Predicting the compressive strength of concrete is important to assess the load-carrying capacity of a structure. However, the use of blended cements to accrue the technical, economic and environmental benefits has increased the complexity of prediction models. Artificial Neural Networks (ANNs) have been used for predicting the compressive strength of ordinary Portland cement concrete, i.e., concrete produced without the addition of supplementary cementing materials. In this study, models to predict the compressive strength of blended cement concrete prepared with a natural pozzolan were developed using regression models and single- and 2-phase learning ANNs. Back-propagation (BP), Levenberg-Marquardt (LM) and Conjugate Gradient Descent (CGD) methods were used for training the ANNs. A 2-phase learning algorithm is proposed for the first time in this study for predictive modeling of the compressive strength of blended cement concrete. The output of these predictive models indicates that the use of a 2-phase learning algorithm will provide better results than the linear regression model or the traditional single-phase ANN models.

Synthesis, Characterization, Absorbance, Fluorescence and Non Linear Optical Properties of Some Donor Acceptor Chromophores

Asiri, Abdullah M.,Khan, Salman A.,Al-Amoudi, Muhammed S.,Alamry, Kalid A. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

Three carbazole chromophores featuring dicyano, cyano, ethyl acetate and dimethyl acetate groups as an acceptor moiety with a ${\pi}$-conjugated spacer and $N$-methyl dibenzo[$b$]pyrole as donor were synthesized by Knovenagel condensation and characterized by IR, $^1HNMR$, $^{13}CNMR$, UV-vis, fluorescence spectroscopy, electrochemistry and theoretical B3LYP/6-$311G^*$ level whilst NLO properties and spectroscopic quantities were calculated. Calculations showed remarkable trend with HOMO located on the donor moiety and LUMO on the acceptors dicyano methylene, cyano, ethyl acetate methylene and dimethyl acetate methylene. In agreement with the calculations, solvatochromic, behavior intramolecular charge transfer band was observed in the visible region.

Synthesis, Characterization, Absorbance, Fluorescence and Non Linear Optical Properties of Some Donor Acceptor Chromophores

Abdullah M. Asiri,Salman A. Khan,Muhammed S. Al-Amoudi,Kalid A. Alamry 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

Three carbazole chromophores featuring dicyano, cyano, ethyl acetate and dimethyl acetate groups as an acceptor moiety with a π-conjugated spacer and N-methyl dibenzo[b]pyrole as donor were synthesized by Knovenagel condensation and characterized by IR, 1HNMR, 13CNMR, UV-vis, fluorescence spectroscopy, electrochemistry and theoretical B3LYP/6-311G* level whilst NLO properties and spectroscopic quantities were calculated. Calculations showed remarkable trend with HOMO located on the donor moiety and LUMO on the acceptors dicyano methylene, cyano, ethyl acetate methylene and dimethyl acetate methylene. In agreement with the calculations, solvatochromic, behavior intramolecular charge transfer band was observed in the visible region.