Abstract: As a result of increased global concern about sustainability and climate change issues; developed Countries committed to finding techniques to conserve resources and achieve a balanced development. Achieving such goals requires more efficient and responsive urban management tools. Accustomed tools are ineffective to enabling cities to achieve such goals. Since 1990, global awareness has been directed towards using ICT in urban management. Creating a smart self-organizing system to manage and monitor cities' performance can accelerate improving of economic competitiveness, sustainability and quality of life. Egypt has an ambitious strategy: Egypt's 2030 vision for achieving sustainability and improving the quality of life. while, current urban management systems cannot accomplish such tasks. Therefore, this paper aimed to develop a conceptual model for a GIS-based urban management tool that enabling Egyptian cities to achieve Egypt's vision 2030. To achieve this goal the researcher relied on: 1) Recognizing the city's self-organizing system and identifying the role of geographic information systems in managing the urban transformation process and monitoring the city's performance; 2) Evaluating the capability of key performance indicators that were developed to measure the achievement of Egypt's 2030 vision. To achieve the first goal, a systematic literature review was conducted; while to achieve the second goal, KPIs of Egypt's 2030 vision were assessed with using strategic objectives/KPIs matrix as well as using comparative analysis with international evaluating systems. The contribution of this paper is twofold: 1 - Theoretical contribution that built the bridge between the theory of self-organizing system and the management of cities; 2- Practical contribution represented by: a) the conceptual model, which helps in understanding the components of the smart system for monitoring and evaluating the performance of cities, and the relationship between them; and b) The evolved list of KPIs that track the city's performance in the six domains of city (economy, environment, mobility, living, community, and governance), to ensure achieving desired goals of Egypt's 2030 vision.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.

One of the major concerns of carbon fiber-reinforced nylon 6 composites (CF/Nylon 6) is its sensitivity to environmental degradation, especially hygrothermal aging. In this study, neat nylon 6 plates and unidirectional CF/Nylon 6 laminates with different fiber orientations manufactured by hot compression method were subjected to water absorption tests by immersing them in 80 °C and 98 °C hot water for various time durations. The corresponding flexural mechanical properties, including the flexural modulus and flexural strength, of the as-prepared samples before and after water absorption were evaluated by using three-point bending tests. The effects of immersion time, fiber orientation, and water temperature on the flexural properties are discussed. Flexural cyclic tests were conducted to evaluate the stiffness degradation of neat nylon 6 and unidirectional CF/Nylon 6 laminates. Optical observation and scanning electron microscopy were used to observe the fracture behavior of unidirectional CF/Nylon 6 laminates before and after water absorption. Results indicated that the flexural modulus and strength of unidirectional CF/Nylon 6 laminates in different fiber orientations decreased by ≈ 8%–60% and ≈40%–60% after hot water immersion, which was mainly caused by the weakened matrix (the cleavage reaction of the main chain and plasticization of the matrix) and weakened interfacial properties (attack on the interface by hot water). The fracture behavior of 0° CF/Nylon 6 laminates after water immersion tended to be more ductile than those without hot water immersion.

This research article investigated the effect of stacking sequence of glass fibers on the notched and unnotched tensile strength of glass fibers plies reinforced epoxy matrix composites fabricated by the hand lay-up technique. The orientation of glass fabrics was kept at [(0/90)]5, [(45/-45)]5 and [(0/90), (45/-45), ]s and all the laminates were prepared using five plies for different stacking sequences with fiber volume content of 38.6 vol.% with different ratios of the specimen hole diameter to the specimen width with three different values (0.1, 0.2, 0.5). The notch sensitivity of these composites was evaluated applying Whitney-Nuismer mathematical model. The results indicated that the composites with [(0/90)]5 stacking sequence displays the highest tensile unnotched strength, whereas the composites with [±45°]5 stacking sequence displays the least strength. Moreover, the notch sensitivity of [±45°]5 composites is almost higher than those of other stacking sequences with different D/W ratios. On the other hand, the notch sensitivity of [(0/90), (45/-45), ]s composites is slightly lower than those of [(0/90)]5 composite structures for different D/W ratios. Moreover, SEM micrographs indicates the most common failure modes for [(0/90), (45/-45), ]s and [(45/-45)]5 are more significant delamination and matrix cracking than that of [(0, 90)]5.

This research article investigated the effect of stacking sequence of glass fibers on the notched and unnotched tensile strength of glass fibers plies reinforced epoxy matrix composites fabricated by the hand lay-up technique. The orientation of glass fabrics was kept at [(0/90)]5, [(45/-45)]5 and [(0/90), (45/-45), ]s and all the laminates were prepared using five plies for different stacking sequences with fiber volume content of 38.6 vol.% with different ratios of the specimen hole diameter to the specimen width with three different values (0.1, 0.2, 0.5). The notch sensitivity of these composites was evaluated applying Whitney-Nuismer mathematical model. The results indicated that the composites with [(0/90)]5 stacking sequence displays the highest tensile unnotched strength, whereas the composites with [±45°]5 stacking sequence displays the least strength. Moreover, the notch sensitivity of [±45°]5 composites is almost higher than those of other stacking sequences with different D/W ratios. On the other hand, the notch sensitivity of [(0/90), (45/-45), ]s composites is slightly lower than those of [(0/90)]5 composite structures for different D/W ratios. Moreover, SEM micrographs indicates the most common failure modes for [(0/90), (45/-45), ]s and [(45/-45)]5 are more significant delamination and matrix cracking than that of [(0, 90)]5.

This research article investigated the effect of stacking sequence of glass fibers on the notched and unnotched tensile strength of glass fibers plies reinforced epoxy matrix composites fabricated by the hand lay-up technique. The orientation of glass fabrics was kept at [(0/90)]5, [(45/-45)]5 and [(0/90), (45/-45), ]s and all the laminates were prepared using five plies for different stacking sequences with fiber volume content of 38.6 vol.% with different ratios of the specimen hole diameter to the specimen width with three different values (0.1, 0.2, 0.5). The notch sensitivity of these composites was evaluated applying Whitney-Nuismer mathematical model. The results indicated that the composites with [(0/90)]5 stacking sequence displays the highest tensile unnotched strength, whereas the composites with [±45°]5 stacking sequence displays the least strength. Moreover, the notch sensitivity of [±45°]5 composites is almost higher than those of other stacking sequences with different D/W ratios. On the other hand, the notch sensitivity of [(0/90), (45/-45), ]s composites is slightly lower than those of [(0/90)]5 composite structures for different D/W ratios. Moreover, SEM micrographs indicates the most common failure modes for [(0/90), (45/-45), ]s and [(45/-45)]5 are more significant delamination and matrix cracking than that of [(0, 90)]5.

This research investigated the effect of different environmental conditions including moisture, saline and alkaline conditions on the notch sensitivity of short and 2D plain woven glass fibers reinforced epoxy matrix composites fabricated by the hand lay-up technique with fiber volume content of 23.5 and 38.6 vol.%, respectively. The test was carried out through open hole tension test at constant ratio of (D/W = 0.2) and the notch sensitivity of these composites under different environments was evaluated by comparing the notched tensile strength and the characteristic distance (do) of these composites applying Whitney-Nuismer mathematical model. The results indicated that the environmental exposure has a pronounced negative effect on the notched tensile strength of all composites compared to the unconditioned state (virgin state). Moreover, the fracture zone of the composites under the alkaline environment is smooth and shows much less fiber pull out validated by SEM micrographs which distinguishes brittle failure.

This research investigated the effect of different environmental conditions including moisture, saline and alkaline conditions on the notch sensitivity of short and 2D plain woven glass fibers reinforced epoxy matrix composites fabricated by the hand lay-up technique with fiber volume content of 23.5 and 38.6 vol.%, respectively. The test was carried out through open hole tension test at constant ratio of (D/W = 0.2) and the notch sensitivity of these composites under different environments was evaluated by comparing the notched tensile strength and the characteristic distance (do) of these composites applying Whitney-Nuismer mathematical model. The results indicated that the environmental exposure has a pronounced negative effect on the notched tensile strength of all composites compared to the unconditioned state (virgin state). Moreover, the fracture zone of the composites under the alkaline environment is smooth and shows much less fiber pull out validated by SEM micrographs which distinguishes brittle failure.