Synthesis of novel high performance Polyurethane nanocomposites from castor oil as renewable Polyol : study on mechanical, thermal and barrier properties

Polyurethane nanocomposite is one of the promising materials and attracts many researchers to explore its potential. This work is aimed to develop a series of polyurethanes (PUs) based on castor oil with polyols as a renewable resource incorporated with different types of nano-fillers (organic and inorganic) to study the improved physico-chemical behaviour of novel polyurethanes fabricated with organically modified clay and purified Multi-Walled Carbon Nanotubes (MWCNTs) nanofillers; forming nanocomposites film by an in-situ polymerization technique and assisted by ultrasonication mixed at various times. Toluene diisocyanate (TDI) and chain extender 1, 4-butane diol (BDO) were employed with polyols to produce COPUs- (Cloisite 30B / MWCNTs) nanocomposites. The amount of nanofillers was varied from 0% to 5% wt for Cloisite 30B and for MWCNTs, the nanofillers range from 0% to 1% wt. The synthesized PU nanocomposites were characterized for different physical properties such as mechanical and morphology changes, oxidative thermal stability as well as sample purity and surface area studies using the Fourier Transform Infrared Spectroscopy (FTIR), the Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). Surface area was studied using the Brunauer-Emmet-Teller (BET) technique and elemental ratios were investigated using energy dispersive X-ray analysis (EDX) with the attached equipment in FESEM spectroscopy. The barrier properties were investigated by looking at nitrogen permeability measurements using a membrane separation unit. The thermal and mechanical properties of the COPUs matrix were found significantly improved with the incorporation of organoclay and MWCNTs. The purified MWCNTs were proven to have higher compatibility compared to organoclay in polymer matrix at even low concentrations of MWCNTs (0.3%), as results achieved presented higher d spacing, mechanical and thermal properties as shown in different instrumental analyses compared to its counterpart, organoclay (3 wt %). Tensile properties showed an improvement of ~ 324% in tensile strength and a decrease of ~74% in elongation at break with 5 wt% organoclay, while COPUs - MWCNTs nanocomposites depicted a massive development in tensile strength and lowering down of elongation at break with 1wt% (~640% and ~ 80%). Thermal properties depicted an increase of 10-30 oC in COPUs–C30B nanocomposites, while a significant increase of degradation temperature (~ 50 oC) was observed in 0.3 wt% of MWCNTs in the COPUs matrix. A major permeability reduction (~25 % and ~ 50%) was attained with 5 wt% of organoclay and 0.5 wt% MWCNTs loaded nanocomposites, compared to pure COPUs. The optimization study was conducted using a response surface methodology (RSM) which included the Central composite design (CCD) with three factors; temperature, time and the amount of nanofillers. An increase in temperature and nanofillers amount favoured the nanocomposites polymerization up to a certain extent. The optimum tensile strength obtained was 1.997 MPa at temperature 90 oC and wt% 4.99% for clay and 2.207 MPa at temperature 90 oC and wt% 1% for MWCNTs respectively

Evaluation study of IEEE 1609.4 performance for safety and non-safety messages dissemination

The IEEE 1609.4 was developed to support multi-channel operation and channel switching procedure in order to provide both safety and non-safety vehicular applications. However, this protocol has some drawback because it does not make efficient usage of channel bandwidth resources for single radio WAVE devices and suffer from high bounded delay and lost packet especially for large-scale networks in terms of the number of active nodes. This paper evaluates IEEE 1609.4 multi-channel protocol performance for safety and non-safety application and compare it with the IEEE 802.11p single channel protocol. Multi-channel and single channel protocols are analyzed in different environments to investigate their performance. By relying on a realistic dataset and using OMNeT++ simulation tool as network simulator, SUMO as traffic simulator and coupling them by employing Veins framework. Performance evaluation results show that the delay of single channel protocol IEEE 802.11p has been degraded 36% compared with multi-channel protocol

Well-Posedness And Symmetry Properties Of Free Boundary Problems For Some Non-Linear Degenerate Elliptic Second Order Partial Differential Equations

In the first part of this thesis, a bifurcation about the uniqueness of a solution of a singularly perturbed free boundary problem of phase transition associated with the $p$-Laplacian, subject to given boundary condition is proved in the first chapter. We show this phenomenon by proving the existence of a third solution through the Mountain Pass Lemma when the boundary data decreases below a threshold. In the second chapter and third chapter, we prove the convergence of an evolution to stable solutions, and show the Mountain Pass solution is unstable in this sense. In the second part of this thesis, we study a singularly perturbed free boundary problem arising from a real problem associated with a Radiographic Integrated Test Stand and concerning a solution of the equation $\Delta u = f(u)$ in a domain $\Omega$ subject to constant boundary data, where the function $f$ in general is not monotone. In chapter 4, we let the domain $\Omega$ be a perfect ring and we incorporate a new idea of radial correction into the classical moving plane method to prove the radial symmetry of a solution. In chapter 5, we let the domain $\Omega$ be slightly shifted from a ring and we establish the stability of the solution by showing the approximate radial symmetry of the free boundary and the solution. For this purpose, we complete the proof via an evolutionary point of view, as an elliptic comparison principle is false, nevertheless a parabolic one holds

The use of special economic zones to drive sustainable development in Egypt: A case study on the Suez Canal region

One major problem facing Egypt is improper allocation of the country’s resources that potentially enhancing Egypt’s development. The Suez Canal Zone is one of these misused resources. In recent years, the Suez Canal area has not been efficiently exploited in parallel to its geographical importance in the world trade route. Thus, it is essential to set a sustainable development strategy and implemented it properly in order to upgrade this area and reap its potential advantages which may contribute to the country prosperity. Unless the Suez Canal region is efficiently managed, Egypt risks losing valuable development opportunities. This research argues that Special Economic Zones (SEZs) could offer a successful way to drive sustainable development in the country, provided this economic zone is appropriately established and customized to fits Egypt needs. The concept of SEZs is gaining global recognition and acceptance, particularly since its successful performance in the Asian Tigers countries, amongst others. Despite these achievements, SEZs in certain developing countries have negatively impacted on the sustainable national growth. Because there is no unified model to suit every situation, it is essential to plan a well-defined framework in the Suez Canal economic zone (SCZone) that supports inclusive growth in Egypt generally and in the Suez Canal region particularly. Such a framework could be built around a long-term commitment which supports economic growth in Egypt, relying on solid social and environmental standards. This dissertation focused on analyzing the role of the current Egyptian special economic zones in achieving its objective, and accordingly proposed a sustainable strategy that supports Egypt vision 2030 in the SCZone. Ultimately, this dissertation found that during 2002-2018 period, SEZs in the Suez Canal region have a significant positive impact on the economic growth whereas they have a significant negative effect on the social and environmental standards. Thus, for making growth more inclusive, the government should have more responsibility for improving the human capital and supporting clean production practices in the SCZone

Active Debris Removal Mapping Project

Space debris discussions initiated with the start of the space age 55 years ago and have seen special interest in current years. This is due to the large increase in the number of space debris which has led to an increased threat of collision with operational space systems and of unsafe reentry. Due to this increased interest in this area, many different methods have been proposed in recent years for mitigation and space debris removal, some of which have even secured funding from space agencies for further development. These include ground based lasers and space based systems which use electro-dynamic tethers, solar sails or inflatable components. While each method has its own pros and cons, some of these concepts seem to be more suitable for the short term and others for the long term. This paper identifies major performance measures for space debris removal systems based on current rules and regulations and maps the performance of the ADR technologies based on these criteria. The map can help prioritize removal concepts and required technologies in order to better meet current needs

Use of expanded polystyrene in developing solid and hollow block masonry units

Light weight mortar of various densities are developed using Expanded polystyrene (EPS) to partially substitute sand. Lightweight mortars are used herein to develop three types of lightweight hollow blocks: 1-plain, 2- steel wire mesh reinforced (ferrocement) and 3- GFRP mesh reinforced (fibro-cement) as well as lightweight solid bricks. The objective of this research is to obtain lightweight masonry units of sufficient mechanical, long-term and thermal characteristics for low-rise building applications in arid environments. Different tests were conducted to assess the mechanical strength; durability and thermal conductivity. Five mixtures were prepared; four EPS mortar mixes with average density range 1748, 1498, 1258, 988 kg/m3, depending on the EPS content and a control mortar mix with average density 2118.4 kg/m3. The mechanical test program included the measurement of the compressive strength of cubes, cylinders, hollow blocks and solid bricks, in addition to the measurement of the static modulus of elasticity, the stress-strain curve, and splitting tensile strength of cylindrical specimens. The durability test program was conducted wholly on hollow blocks and involved 48-hour water absorption test as well as subjecting them to wet-dry cycles of saturated salt solution and of 5% concentration sulfuric acid solution. The thermal conductivity test was conducted with the hot wire method on solid bricks. A finite element numerical model was developed on the GAMBIT-FLUENT package to assess the equivalent thermal conductivity of the plain hollow blocks. The effect of the three mode of heat transfer, namely, conduction, convection and radiation was reported and the interaction between them was analyzed. The results showed that the addition of EPS aggregates to mortar reduced the density as well as the mechanical properties. For a density range between 2200 and 980 kg/m3, the compressive strength of the cubes ranged between 32.6 and 3.5 MPa, and the net compressive strength of the hollow blocks ranged between 9.5 and 2.4 MPa. For the same density range the modulus of elasticity and the split tensile ranged between 15.5 and 1.2 GPa, and 2.87 and 0.55 MPa respectively. The presence of EPS in the cement matrix tremendously improved the failure pattern of all the EPS mixes. On the other hand, the durability cycles proved that EPS hollow blocks were resilient to acid and salt exposure. The weight loss and compressive strength loss of the hollow blocks due to ettringite leach decreased significantly with the addition of EPS aggregates. The salt wet-dry cycles adversely affected the compressive strength plain, ferrocement and GFRP mesh reinforced hollow blocks. The plain hollow blocks suffered from efflorescence and salt crystallization that adversely affected the compressive strength. Moreover, the compressive strength of the GFRP mesh reinforced hollow blocks was the most affected and the ferrocement EPS hollow blocks were less affected. Furthermore, the thermal conductivity tests showed that the inclusion of EPS aggregates decreased the thermal conductivity of mortar remarkably. The average thermal conductivity of the control bricks was 1.8 W/m. K. and ranged between 1.53 and 0.16 W/m. K. for the EPS mortar bricks. However, the thermal conductivity obtained numerically for the hollow blocks considering all heat transfer modes was 1.43 W/m. K. for the control blocks and ranged between 1.27 and 0.25 W/m. K. for the densest and lightest EPS mortar hollow blocks respectively. The equivalent thermal conductivity determined from the thermal model suggested that lighter EPS hollow blocks of density range 1258 and 988 kg/m3 would be more thermally efficient if they were solid. This is because, thermal conductivity of the hollow blocks inflated when the radiation heat transfer mode was accounted for. Finally, the results show that EPS mortar hollow blocks and bricks are suitable for non-load bearing application of exterior walls within the limits presented by ASTM C 129 and the Egyptian Standards (EOS 2005/42 2005), maintain their integrity while resisting salts and acids and have superior thermal insulation

Cytotoxic effect of the purified lectin from locally Isolate Acinetobacter baumannii on Hep-2 tumor cell line

Lectins are glycoproteins of non-immune origin which have a wide range of application in medical field. In this study, a novel strain, Acinetobacter baumannii S4 gave the highest production level of lectin by microscopic glass slide and microtiter plate methods and found that lectin agglutinated non-specifically red blood cells of human type A+, B+, AB+ and O+ also  the blood group O+ was the best among the other blood groups. Purification of the lectin was achieved by35% saturation ammonium sulfate followed by affinity ion-exchange chromatography on DEAE -cellulose column and  gel filtration chromatography Sephadex G-75 column with a yield of 36% and a purification fold of 4.66.This study showed that the purified lectin has a cytotoxic effects on cancer cell (Hep-2) as could be seen from their effects on inhibition percentage and the significant differences (p<0.05) which was observed by increasing the inhibition percentage as the concentration and time were increased. The higher level of inhibition(64%) was obtained at concentration56.25?g/ml after 72hour of exposure and when the concentration was increased more than56.25?g/ml, the inhibition rate was decreased

Nonlinear Analysis of Arch hollow box RC Beams with openings in different locations

This study is devoted to investigate the behavior and performance of arch reinforced concrete (R.C.) beams with openings in different locations along the beam at degrees of 15o, 30o, 45o, 67.5o and 90o. For the analysis, the ANSYS V.16.0 software is used. The ordinary R.C. was modeled by 8-noded isoparametric brick elements, while the steel reinforcing bars were modeled as axial members (bar elements) connecting opposite nodes in the brick elements with full interaction assumption. The CFRP strips were modeled by shell elements. Results show that the ultimate capacity of the beams decreased when the location of the opening changed from 15o to 45o and return to increase when the location of the opening changed from 45o to 90o. Keywords: reinforced concrete beam, arch beam, opening