Application of Artificial Neural Network to Predict the Properties of Permeable Concrete

The structure of permeable concrete has been the primary reason for its use in construction. Permeable concrete is composed of water, cement, aggregate, and little-to no-fines resulting in the presence of a significant number of voids. This makes permeable concrete an ideal solution to water accumulation issues as it acts as a drainage system. This study employs a feedforward backpropagation artificial neural network model that combines experimental laboratory data from previous studies with appropriate network architectures and training techniques. The purpose of the analysis is to develop a reliable functional relationship, based on water-cement ratio, aggregate-cement ratio, and density parameters, with which to estimate the compressive strength, porosity, and water permeability of permeable concrete. Multiple linear regression correlations are also established to predict and correlate these inputs and outputs. The two derived methods are then compared and discussed. The results reveal that ANN is better to anticipate the permeable concrete properties than regression analysis

The role of mega projects in redefining housing development in Gulf cities

Since the end of the 1990s large scale mega projects have been initiated in Gulf cities to enable an unprecedented urban growth and the expansion of new economic sectors. In this respect, mega projects have played a key role in redefining housing developments in Gulf cities. This paper explores the newly emerging housing typologies and their distinctive roles in defining new urban environments. The selected case studies are located in the Jumeirah District in Dubai, which can be seen as the first prototype of a large cohesive development area that has been built of nine rather differing mega projects including the iconic Palm project and one of the largest residential high-rise agglomerations in the Middle East. The paper is based on the evaluation of official planning data from each project and field observations. Conclusions are drawn to highlight key implications while identifying housing development tendencies

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

AbstractThe new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections

Migrant Knowledge Workers’ Perceptions of Housing Conditions in Gulf Cities

© 2017, The Author(s). The various efforts in diversifying local economies in most Gulf States led to the emergence of new medium to high-income groups of migrant knowledge workers whose efforts are required to develop various new economic sectors. This paper aims to investigate the current housing conditions and perceptions of these migrant communities to identify key similarities and differences with respect to housing made available to them and depending on their cultural background. To this end, the methodology involves field surveys to explore the three main housing typologies for higher-income groups and a questionnaire with a total of 258 knowledge workers in the city of Doha as a representative case to investigate the associated perceptions of four dominant groups from different cultural backgrounds. The findings reveal that there is a distinct social segregation between cultural groups, which is mainly rooted in varying income levels. Furthermore, the supply-driven market has hardly integrated cultural needs of migrants and thus diversified and inclusive housing has been identified as major planning and design challenge

Exploring health professionals’ and women's awareness of models of maternity care evidence

A Cochrane systematic review has shown midwife-led continuity models of care provide explicit benefits for mothers and babies compared with other models of maternity care, with a comparable level of safety. The Cochrane review has had much international impact. This study explored the local impact of the review, alongside other midwife-led care evidence and guidelines. Electronic surveys were undertaken exploring women's and health professionals' awareness of models of maternity care evidence, including midwife-led care and homebirth, and how they utilise evidence to guide their choices and practice. A low awareness of much of the available evidence was shown among the women and the professionals. There is a need for better dissemination of information to professionals as they are women's preferred source of information about the options available for place of birth and midwife-led care

A chronological exploration of the evolution of housing typologies in Gulf cities

This paper traces the evolution of housing typologies in four major cities in the Gulf region, namely Doha, Dubai, Abu Dhabi and Manama. The study reviews the formation and historical events in the region, which had a significant impact on new social as well as economic realities and consequently evolving housing types during the last two centuries. The methodological approach is based on reviewing a number of case studies representing local housing typologies throughout distinctive historic periods which were categorized in four periods: the post-nomadic, traditional, modern, and contemporary. The main objective is to identify the process of transformation by applying a comparative assessment of the different periods in order to examine continuities or ruptures between them. Thus, particular layout elements were analysed and compared. Conclusions are drawn to underline contemporary challenges while offering projections for future housing typologies in the selected cities and other similar ones

G019 Cholesterol depletion enhances Kv1.5-encoded K+ current by increasing Rab11-mediated recycling

Membrane lipid composition is a major determinant of protein organisation in the cell membrane. In a previous study, we reported that depletion of membrane cholesterol by methyl-fÒ-cyclodextrin (MCD) causes a marked increase in Kv1.5-current (Ikur) in neonatal cardiac myocytes. Here, we examined the mechanisms of the cholesterol effects on potassium current in adult rat cardiomyocytes (ARC). GFP-tagged Kv1.5 channels were transduced in ARC using adenoviral vectors and patch clamp experiments were performed to record whole-cell currents and single channel activity. Fluorescence recovery after photobleaching (FRAP) technique was used to investigate GFP-Kv1.5 channels mobility; 3D-epifluorescence microscopy was conducted to follow Kv1.5 channels trafficking.In both freshly isolated and cultured ARC over-expressing GFP-Kv1.5 channels, MCD induced a rapid (< 7min) increase in Ikur but not Ito. On the contrary, incubation with the cholesterol donor LDL reduced Ikur. Single channel experiments revealed that MCD application caused a progressive and drastic increase of the number of active channels. Moreover, FRAP experiments showed that MCD reduced both mobility and recovery of GFP-Kv1.5. Several steps of the trafficking process of ion channels were studied. Blocking SNARE-mediated exocytosis with N-ethylmaleimide prevented the MCD-effect on Ikur. While disruption of Golgi complex/secretion pathway with brefeldine-A had no effect, manipulation of GTP-ases activity with GTP-f×-S suppressed the MCD effect. Transfection with a dominant negative (DN) form of Rab11 effect but not Rab4 DN prevented the MCD. Moreover, Kv1.5 channels co-immunoprecipitated with Rab11 which is stringly expressed in myocardium and ARC (qPCR and western blot). Finally, 3D-microscopy evidenced that Kv1.5 channels association with Rab11-positive recycling endosomes observed in control condition disappeared following cholesterol depletion.ConclusionLowering cholesterol rapidly induces the insertion of Kv1.5 channels by a process that involves vesicle fusion and trafficking processes, particularly the Rab11-associated slow recycling pathway. Given the role of Kv1.5 channel in normal and pathological atrial electrical properties, this study opens news perspectives for therapeutic modulation of cardiac myocytes excitability

Bubble formation in ϕ6\phi^6 potential

Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for $\phi^6$ potential. The equations of motion are solved numerically to obtain O(4) spherical symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formation. The range of validity of the thin-wall approximation (TWA) is investigated. An analytical solution for the bounce is presented, which reproduces the action in the thin-wall as well as the thick-wall limits.Comment: 22 pag