Effect of Grinded of Debris of Concrete on the Compressive Strength of Reactive Powder Concrete

إن هذا البحث هو محاولة لزيادة الوعي بمفاهيم الاستدامة في الصناعة الانشائية، من خلال دراسة تأثير استبدال جزء من وزن السمنت (C) أو جزء من وزن مسحوق غبار السيليكا (SF) بمسحوق أنقاض الخرسانة (GDC) على مقاومة انضغاط خرسانة المساحيق الفعالة (RPC). تم تصميم وتنفيذ خلطة مرجعية من (RPC) خالية من (GDC)، وستة خلطات من نفس نوع الخرسانة تحتوي على (GDC). ثلاثة من الخلطات الخرسانية تم تصميمها لبيان تأثير استبدال 5%، 10% و15% من وزن (C) بـ (GDC). بينما تم تصميم الخلطات الثلاثة الأخرى لبيان تأثير استبدال 10%، 20% و30% من وزن (SF) بـ (GDC). أظهرت النتائج إمكانية الحصول على مستويات عالية من مقاومة الانضغاط (fcu) لخلطات (RPC) الحاوية على (GDC). تم ملاحظة حدوث تأثيرات سلبية طفيفة على مستويات (fcu) بسبب استخدام (GDC). بينت النتائج ان هذه التأثيرات ليست على مستوى واحد وتتباين استنادا الى نوع المادة المستبدلة، نسبة الاستبدال وعمر الخرسانة. كان تأثير استبدال جزء من وزن الـ (C) بـ (GDC) أكثر وضوحا من تأثير استبدال جزء من وزن الـ (SF) بـ (GDC). أدت زيادة نسبة الاستبدال الى تقليل قيم (fcu). أكدت النتائج ان فعالية وتأثير الـ (GDC) قريب جدا من فعالية وتأثير الـ (SF) خاصة في الأعمار المتقدمة للخرسانة.This investigation is an attempt to increase the sensibility of sustainability in the construction industry through studying the influence of the replacement part of cement (C) or silica fume (SF) content with a Grinded Debris of Concrete (GDC) on the compressive strength (fcu) of Reactive Powder Concrete (RPC). Reference RPC mix without GDC and other six RPC mixes with GDC are designed, mixed, molded and tested. Three mixes are designed to show the effects of replacement 5%, 10% and 15% of C with GDC. While, the other three are designed to show the effects of replacement 10%, 20% and 30% of SF with GDC. The results exhibited that high (fcu) can be achieved by involving the GDC in the mixes of RPC. However, a very little negative effect on (fcu) can be noticed. This effect differs according to the type of the replaced material, percentage of replacement and the age of concrete. The impact of replacing a part of C with GDC is clearer than that of replacing a part of SF with GDC. Increasing the percentage of replacement leads to decrease the values of (fcu). GDC has a very close action as SF especially at later ages

Strengthening of reinforced masonry walls subjected to out-of-plane pseudo-static cyclic load using advanced composite

A number of researchers have conducted experimental tests on unreinforced masonry walls (URM) strengthened with advanced composite materials. Consequently, the strengthening design guidelines are limited in their scope to URM. This research aimed to investigate the behavior of reinforced masonry walls strengthened with advanced composite and subjected to out-of-plane pseudo-static cyclic load. Experimental and analytical studies were conducted to evaluate the performance of different techniques such as near surface mounted (NSM) and externally bonded (EB) fiber reinforced polymer (FRP) with epoxy resin, in addition to NSM with cementitious adhesive and fiber reinforced cementitious material (FRCM). The experimental part included three phases. In the first phase, a series of 42 reinforced masonry walls were tested to study the effectiveness of advanced composites in enhancing out-of-plane flexural capacity. The effect of long-term environmental exposure on strengthening systems was investigated in the second phase of study by testing 10 reinforced masonry walls. The third phase focused on bond behavior between the advanced composite and the concrete masonry unit at different temperatures; 56 specimens were used for this purpose. The results indicated that the non-arching strengthened reinforced masonry wall\u27s behavior was significantly dependent on the type of fiber and fiber reinforcement ratio. The specimens strengthened with glass under combined environmental cycles exhibited an insignificant change in terms of ultimate strength as compared to laboratory conditioned specimens. The theoretical part included the investigation of bond reduction factors, seismic performance, and the nonlinear analysis of strengthened reinforced masonry wall using moment-curvature analysis. As a result of this study, the proposed model for predicting debonding strain and the moment-curvature relation presented an excellent prediction compared to the experimental results --Abstract, page iv

LIPOCALIN-2 AMELIORATES THE SIGNS AND OUTCOMES OF DIABETES MELLITUS IN AN ANIMAL MODEL

Lipocalin-2 (LCN2) is a new adipocytokine consisting of 198 amino acids. It is also referred to as neutrophil gelatinase-associated lipocalin, siderocalin, uterocalin, α1-microglobulin related protein, or 24p3. LCN2 belongs to a large group of transport proteins that are capable of carrying small and lipid-soluble molecules in blood circulation. It has two membrane receptors, megalin/glycoprotein GP330, which binds human LCN2 and SLC22A17 or 24p3R, which forms complexes with mouse Lcn2 protein. LCN2 is encoded by a gene located at chromosome locus 9q34.11. LCN2 was initially isolated from neutrophil granules released at the site of infection and inflammation in humans and from mouse kidney cells. LCN2 kills bacteria by iron depletion during antibacterial innate immune response via sequestering bacterial ferric siderophores enterobactin (Ent). It has a protective role in infection, inflammation, injury and other forms of cellular stress. In addition, it is able to interact with and stabilize matrix metalloproteinase-9 in human neutrophils. Tissue localization and the effect of LCN2 were studied in streptozotocin-induced diabetic rats using morphological, physiological, biochemical and molecular biology techniques. This study shows that LCN2 is co-localized with insulin in normal and diabetic pancreatic β-cells. In addition, LCN2 significantly reduced the plasma levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, bilirubin, cholesterol, triglycerides, low-density lipoprotein and improved the levels of high-density lipoprotein and total protein after the onset of diabetes. LCN2 treatment decreased the plasma levels of BUN, Urea and LIPC in diabetic animals. Moreover, the levels of insulin, C-peptide, amylin, and GIP were significantly increased in diabetic rats treated with LCN2. Furthermore, LCN2 showed a significant antioxidant activity by increasing glutathione reductase, superoxide dismutase and catalase levels in pancreatic tissue of normal and diabetic animals, as well as their levels in the serum. In vitro observations show that LCN2 at a concentration of 10-8 M and 10-12 M caused large and significant increases in insulin release from the INS-1 rat insulinoma cell line. In conclusion, LCN2 ameliorates the acute and chronic complications of diabetes mellitus and appears to be a promising adjuvant therapy in the management of DM

GATED COMMUNITIES IN THE UAE: FROM A SOCIAL SUSTAINABILITY BARRIER TO A CATALYST

Gated communities are commonly defined as residential areas with restricted access, where commonly public spaces are privatized. The main characteristic of gated communities, based on the physical aspect of the development, involves gates, walls, guards, and closed-circuit surveillance. Scholarly studies have focused on the phenomenon of gated communities through covering its implications on the society and the city, where the benefits of this type of development have been frequently questioned. Gated communities have been linked with their negative impacts on the communities as socially segregated areas form the surrounding urban context. Nonetheless, several other studies advocated paradoxical theories related to social bonding, sense of safety, and sense of community that gated communities might provide for its residences. The question that poses itself is: what is the balance point, if any, for gated communities to satisfy the social sustainability for both the communities within the gate and the community outside it? This study seeks to explore the potential for such a balance point through investigating the different aspects and attributes of the case in the context of the UAE with the aim to understand the impact of gated communities on social sustainability within and outside the ‘gates’ of these communities. The Case Study method was used to examine the data closely within the defined urban context through mixed methodological quantitative and qualitative tools. The utilized qualitative research tools included field surveys, interviews, and spatial analysis for relevant maps. Meanwhile, the quantitative research tools included questionnaires and the Space Syntax DepthmapX software for spatial analysis. The research has revealed that it is difficult to reach a ‘perfect’ balance point in-between to satisfy the social sustainability for both communities within the ‘gate’ and the community outside it because ‘safety’ has proven to be more preferable to the interviewed residents of gated communities than ‘connectivity’ with the surrounding urban context. However, some sort of a ‘balance’ could be achieved if local services of the gated communities could be utilized and exploited as the social integration link between the local communities within and outside of the gates. This would convert these services into social nodes for both communities in a way that maintains ‘safety’ while encouraging social ‘connectivity’

The impact of Transformational and Transactional Leadership styles on Organizational learning in health care context

The aim of this research is to examine the impact of leadership styles on organizational learning in health care context at Abu Dhabi Health Services Company (SEHA) in Al Ain region. The study uses a quantitative methodology to answer the research questions. The findings suggest that both transactional and transformational leadership styles are associated with organizational learning. The transformational leadership is linked with organizational learning through learning goal orientation and trust in leaders whereas transactional leadership style is linked with organizational learning through performance goal orientation. The research findings can help senior executives to put strategic plans for their organizational learning development. Also, the research is expected to provide a baseline for health care policy makers on how they can initiate and create a context of organizational learning through enhancements of the leadership role

Quantity and Quality Simulation in Al Ain Water Distribution System

A hydraulic and chlorine simulation is conducted for three selected areas in Al Ain region. WaterCad 7.0, a water distribution system model, was chosen to conduct the simulation of the hydraulic behavior within the water distribution system. The fate of residual chlorine flowing through these systems over time is tracked by this software. The conducted hydraulic model predicts the performance of Al Yahar, AI Dhaher and Sweihan networks. Skeletonaization approach is employed in setting up the model for each system. In this study, the customer storage tanks (CSTs) are taken into consideration in performing the extended period simulation. Each group of (CSTs) is represented by a so-called Internal Storage Tank (IST). AI Yahar and Sweihan areas were selected since they exist at first locations supplied from the main desalination plants located in Abu Dhabi costal boundary called Um AI Nar and Tawillah via AI Saad and Sweihan pumping stations. AI Dhaher area, the third simulated system, is also selected as it is located at the last eastern site of AI Ain region that is supplied from Tawillah and Fujairah desalination plants via UmGhafa reservoir. The three selected networks are located somewhat on the edges of AI Ain region. They are considered district metered areas (DMAs), where each network has an adjusted flow control valve at its feeding sources. Therefore, the flow and the pressure for each system is known. Moreover, a data logger was installed by AI Ain Distribution Company (AADC) at a specific location in each network to record the residual pressure for a duration of one year. The simulation is done utilizing the water demand provided by the company. Water demands vary and consideration of the probabilistic nature of variations leads to more instructive assessment of the performance of the three selected distribution systems. Calibration of the hydraulic model was conducted by tuning the ISTs\u27 capacities and water levels (initial and maximum). Hazen-william coefficients were maintained constant (C=120), as all networks pipes and connections were installed five years ago only in addition to the very good quality of desalinated water passing through each system. Chlorine simulation is conducted and calibrated utilizing the residual chlorine data collected for one year from the same data logger location in each area. With regard to the Chlorination ByProducts, trihalomethanes (THMs) compounds are sampled and analyzed. All obtained results were less than the international limits of 80 ppb. Laboratory experiments were conducted to analyze the formation of TTHM species in flowing pipelines. The results show that bromoform lead the THM species in all samples and at all times. On the other hand, the bromoform was found to undergo major hydrolysis after sometime approaching zero levels. All simulated and calibrated results, i.e. pressures, velocities and residual chlorine are compared to that in the water distribution code issued by Al Ain Distribution Company and with the international standards. From economic point of view, the energy cost for Al Yahar and Sweihan networks is calculated based on 0.05 Dhs/kwh for one and 20 years. Some alternative systems are studied to enhance the performance and efficiency of each network. One of the most important issues discussed is the possibility of removing the customer storage tanks, where cost savings can be achieved by controlling the delivered quantities to each customer tank and eventually enforcing the demand management concept. Installing an elevated tank or more is also discussed and scrutinized. The energy cost is also determined for each option and compared with the original configuration for each network

UNITED ARAB EMIRATES POST OIL STRATEGY: AN EXAMINATION OF DIVERSIFICATION STRATEGIES AND CHALLENGES

For decades, oil-rich countries have been thoroughly discussed in the literature; regarding the heavy dependence on oil revenue for the state’s development, and economic diversification has become one of the main issues of oil-producing countries worldwide, due to the critical situation and different factors and pressures surrounding the global oil market. To achieve the research objectives and to answer the research questions, the paper analyzes the post-oil strategy of the United Arab Emirates and examines its challenges as a country located in a region with abundant oil wealth that has allowed it to become one of the main oil exporters besides other GCC countries. The purpose of this paper is to highlight the initiatives of the United Arab Emirates government to create a good economic environment towards diversification. The paper uses a qualitative methodology by collecting data through in-depth interviews with government officials, experts, and academics in order to collect different views and perspectives concerning this matter. The findings show that the government has a clear vision for diversification which is embodied in the effective laws and policies to enforce the post-oil strategy effectively. The major economic diversification strategies include: investing in research and development, attracting foreign direct investment, developing a petrochemical industry, manufacturing, tourism, aviation, financial services and banking hub, logistical hub, digital economy, and knowledge economy. There are many challenges associated with UAE’s diversification strategy. Economically, there are challenges such as global economic crises, oil price volatility, and exchange rate regime; Geopolitical challenges include regional conflicts and tensions, while cultural and social challenges include: demographic imbalance and low Emirati participation in the private sector. The research concludes with the following policy recommendations: efficient and effective implementation of Emiratization strategies, skill development, and vocational training, developing targeted policies to increase national fertility, and enhancing soft power tools

Prediction of Compressive Strength and Evaluation of Different Theoretical Standards and Proposed Models of Brick Columns Confined with FRP, FRCM, or SRG System

The Strength Capacity of Confined Masonry Column is One of the Topics that Need to Be Studied. in This Study, the Efficiency of using Different Types of Advanced Composite (Non-Corrosive Materials) Such as Fiber Reinforced Polymer (FRP), Fiber Reinforced Cementitious Matrix (FRCM), or Steel Reinforced Grout (SRG) in Confining Masonry Columns is Investigated. a Wide Range of Experimental Database of Masonry Column Specimens Has Been Collected from the Results that Available in Scientific Literatures. Different Theoretical Standards and Proposed Models that Used to Predict the Capacity of Masonry Columns Confined with FRP and FRCM Are Evaluated based on Collected Experimental Database. Since There is No Standard Code or Specific Proposed Model for SRG System, the Confined Capacity of This System is Predicted and Evaluated using the FRCM Proposed Models. the Justification of using These Models is that Both FRCM and SRG Systems Have the Same Concept of using Inorganic Material as a Paste Material. an Index Named Equivalent Fiber Reinforcement Index (EFRI) is Proposed to Capture the Key Factors that Control the Behavior of the Confined Masonry Columns with Different Advanced Composite. This Index is Used as Reference Parameter for the Purpose of the Comparison between Different Strengthening Systems. as a Result, All Types of Advanced Composite Presented a Significant Increase in Ultimate Capacity. Also, the Behavior of the Masonry Columns Was Significantly Dependent on the Type of Fabric Used. Different Modes of Failure Were Reported, Including Crushing of Masonry Block, as Well as a Deboning of FRP from the Masonry Substrate and Deboning or Slippage of Fabric within Inorganic Paste Matrix. Compared with Other Models and Standards, the American Concrete Institute Committee 440 (ACI 440) and American Concrete Institute Committee 549 (ACI 549) Shows Very Good Predictions for the Confined Capacity of Masonry Columns Strengthened by FRP and FRCM or SRG Respectively

Measuring of Subjective and Objective Aesthetics in Planning and Urban Design

The article includes the concept of aesthetics through what has been dealt with in the literature by philosophers and researchers who have addressed this concept in an attempt to derive indicators of aesthetics. The article adopted a descriptive and analytical methodology by reviewing recent literature on the concept of aesthetics and its relation to urban planning and design issues. Many subjective and objective aesthetics indicators have been identified, some of which are classified under real aesthetics, and some under fake aesthetics. The indicators were applied to the Kufa Mosque complex and Sahla Mosque complex as a comparative case study. It was found that the indicators of real aesthetics have a higher weight in determining the final aesthetic judgment on the complex form versus the fake indicators, which in turn reinforced the weighting of the subjective aspect over the objective. This was consistent with the answer to the question directed to the sample about which complexes are more aesthetic. The answer was that the Kufa Mosque complex is most aesthetically. This was proven by the questions directed in the questionnaire, which outweighed the real aesthetic indicators for the Kufa Mosque complex. As for the results of analyzing the indicators of fake aesthetic were equal, as each complex achieved higher values in three indicators. Doi: 10.28991/cej-2021-03091743 Full Text: PD