Quality of service management for non-guaranteed networks

The increasing dominance of multimedia communication posed new requirements for the underlying systems. Multimedia data, formally called continuous media, has time constraints that impose real time limitations for their transmission. Certain levels of service, called Quality of Service (QoS), need to be considered when handling continuous media. The present work utilizes QoS concepts for networks that do not have inherent QoS support. The thesis aims at verifying the possibility of having QoS-controlled communication on non-guaranteed networks. A basic QoS architecture is designed where already existing QoS concepts are adapted to work with non-guaranteed networks. The architecture provides the facilities of QoS specification, mapping, admission, maintenance, monitoring and notification. In addition, a new concept for predictive QoS admission is introduced. The proposed architecture was verified using a prototype system. The results showed an increased percentage of continuous media that arrive on time to their receivers (good put) with higher network loads. The increased good put was at the expense of high network overhead

The Differential Efficiency of Chlorella vulgaris and Oscillatoria sp. to Treat the Municipal Wastewater

The utilization of microalgae to treat wastewater becomes an alternative biological wastewater treatment technique worldwide because of its low cost and environmental clean. Chlorella vulgaris and Oscillatoria sp. were cultured in municipal wastewater under controlled laboratory conditions with continuous light illumination and aeration. Physical properties (pH, TDS and Salinity), and nutrient contents (ammonia, nitrite and total phosphorus)were measured in the raw wastewater. Growth rates of the cultured species in terms of optical densities and cell counts, nutrient salts removal efficiencies were measured during the experimental durations after; 24, 48, 72, 96 , 120 and 144hrs. Lipids, proteins and carbohydrates contents were also evaluated after 144hrs. The recorded optical density of Chlorella vulgaris was 0.188±0.01 at 680 nm and 0.17±0.01 at 750 nm after 24hrs then increased to 1.45±0.002 at 680nm and 1.43±0.01 at 750nm at the end of 120hrs, meanwhile the optical density of Oscillatoria sp. was increased from 0.132±0.01 at 680 nm and 0.102±0.01 at 750 nm after 24hrs to 1.054±0.004 at 680 nm and 0.99±0.002 at 750 nm at the end of 120hrs of the experiment. On the other hand, the cell count of Chlorella vulgaris was enriched from 6.8±2.2 cell/ml after 24hrs to 720±120 cell/ml at the end of 120h of the culturing. Overall, efficiencies of nutrients removal were 99.426%, 100% and 82.211% for ammonia, nitrite and total phosphorus respectively at the end of 120hrs of Chlorella vulgaris culturing, while Oscillatoria sp nutrient removal efficiencies recorded 98.125%, 100% and 84.718% for ammonia, Nitrite and total phosphorus respectively. Chlorella vulgaris biomass was estimated 26.66±7.5% lipid 35.1±1.6% protein and 29.34±3.25% carbohydrate, however Oscillatoria sp. biomass was estimated 11.76±0.79% lipids, 32.9±1.92% protein and 27.36±3.78% carbohydrates. Keywords: municipal Wastewater, Chlorella vulgaris, Oscillatoria sp., nutrient removal, biochemical parameters

Proposed Strategies to Improve Adult Asthma Management in Egypt: Expert Review and Recommendations

Background: Several challenges face asthma management in Egypt, including the high percentage of uncontrolled patients, inadequate compliance, and overuse of short-acting beta-agonists (SABAs) leading to increased asthma-related morbidity and mortality. In this regard, the recent Global Initiative for Asthma (GINA) recommendations included inhaled corticosteroids containing therapy for mild asthma. Local healthcare systems and healthcare professionals (HCPs) often experience practical challenges when implementing global guidelines. Objective: The present expert review aims to outline the development of local guidelines and health policies that integrate global advances in asthma management while addressing unmet needs and challenges in Egypt. Methods: A steering committee of health policymakers and respiratory experts from the principal healthcare sectors in Egypt came together in March 2021 to develop a consent and national guideline for local asthma management, codifying the current challenges and the required elements for adequate control. The recommendations were either evidence-based or consensus-based from the clinical expertise and perspectives of the committee. Results: The committee identified vital challenges facing all chronic airway diseases with initial focus on asthma management in Egypt in diagnosis, data collection, policymaking, patients’ awareness, and physicians’ attitudes. In general, the committee stated that globally adapted management protocols necessitate addressing from diverse perspectives through policymakers, HCPs, and patients. Accordingly, it is vital to provide relevant education for the patient and HCPs. The recommendations emphasize key elements concerning baseline assessment, diagnosis, treatment strategy with regular review of patient progress, and compliance toward the introduced reforms. Conclusions: Full integration of these recommendations into local practice allows physicians to sustain adequate management while reducing preventable exacerbations and unnecessary burdens. The proposed strategies outline efficient patient-centered management that approaches asthma as an inflflammatory condition, encouraging health promotion and patients’ compliance

Conformational analysis investigation into the influence of nano-porosity of ultra-permeable ultra-selective polyimides on its diffusivity as potential membranes for use in the «green» separation of natural gases

Nano-porous polymers of intrinsic microporosity, PIM, have exhibited excellent permeability and selectivity characteristics that could be utilized in an environmentally friendly gas separation process. A full understanding of the mechanism through which these membranes effectively and selectively allow for the permeation of specific gases will lead to further development of these membranes. Three factors obviously influenced the conformational behavior of these polymers, which are the presence of electronegative atoms, the presence of non-linearity in the polymeric backbones (backbone kinks) and the presence of bulky side groups on the polymeric chains. The dipole moment increased sharply with the presence of backbone kinks more than any other factor. Replacing the fluorine atoms with bulky alkyl groups didn\u27t influence the dipole moment greatly indicating that the size of the side chains had much less dramatic influence on the dipole moment than having a bent backbone. Similarly, the presence of the backbone kinks in the polymeric chains influenced the polymeric chains to assume less extended configuration causing the torsional angles around the interconnecting bonds unable to cross the high potential energy barriers. The presence of the bulky side groups also caused the energy barriers of the cis-configurations to increase dramatically, which prevented the polymeric segments from experiencing full rotation about the connecting bonds. For these polymers, it was clear that the fully extended configurations are the preferred configurations in the absence of strong electronegative atoms, backbones kinks or bulky side groups. The addition of any of these factors to the polymeric structures resulted in the polymeric chains being forced to assume less extended configurations. Rather interestingly, the length or bulkiness of the side groups didn\u27t affect the end-to-end distance distribution to a great deal since the presence of quite large bulky side chain such as the pentyl group has caused the polymeric chains to revert back to the fully extended configurations possibly due to the quite high potential energy barriers that the chains have to cross to reach the less extended configurational states

Molecular dynamics investigation into the high permeability and high selectivity of nano-porous polyimide membranes for the \green separation of natural gas

Molecular modeling techniques were used to investigate the permeability and selectivity of various natural gas components through nano-porous polyimide membranes for the environmentally-friendly green separation of natural gas. The polyimide membranes showed the ability of creating nano-scale channels within the polymeric matrix during the molecular mobility of the polymeric chains through which specific gas molecules can penetrate the membrane surface. The four natural gas components investigated in this study were methane, ethane, propane and butane, all hydrocarbon materials of similar basic chemical structures. The self-diffusion coefficients of the gas molecules were thus used to express the permeability of the various gases through the membranes since the solubility of the gas molecules in the polymeric substances were assumed to be constant. Methane showed a noticeably high self-diffusion coefficient calculated from the application of Einstein relation to the generated molecular dynamics trajectories. All other gases had similar values for the self-diffusion coefficients, which indicate the ability of the methane molecules to penetrate the polymeric membrane in a much larger speed due to a possible matching between the methane molecular size and the size of the interconnected nano-channels within the membranes. The results also showed that the polymer molecules had lower self-diffusion coefficients than the gas ones due to the large size of the polymeric segments. Other structural parameters such as the radial distribution function in direct relationship to the local packing of the polymeric segments and penetrant molecules are also illustrated. © 2012 The Surface Science Society of Japan

Novel Food Packaging Based on Naturally-Plasticized Poly (Lactic Acid) for Enhanced Nutritional Storage

In order to contribute to sustainable development, alternatives to fuel-based polymers must be employed. Poly (lactic acid) (PLA) is a common natural polymer that is currently used in food packaging applications but with limited applicability due to its poor mechanical behavior (high elastic modulus and low elongation at break). To overcome PLA weaknesses and to enhance its flexibility and applicability in food packaging while preserving its environmentally friendly nature, three natural plasticizers, namely polyethylene glycol (PEG), tri n-butyl citrate (TBC), and triacetin (TA), are employed in this study. Stress-strain measurements showed that PEG did not enhance the mechanical response of PLA. Strangely, increasing PEG content has resulted in worsening the mechanical response of PLA, which was attributed to the formation of hydrogen bonding between PEG hydroxyl groups and PLA carbonyl oxygens, which limited the extensibility of the chains and increased its stiffness. Different concentrations of TBC and TA plasticizers were far more efficient when compared to PEG ones. The energy values of PLA/ TBC and PLA/TA samples have shown significant increase over PLA/PEG samples. Quite interestingly, stress relaxation of 10% PLA/TA samples showed an anomaly with upturn in the sample modulus at higher elongation values indicating an increased toughness of the samples with strain. This unique behavior was attributed to the formation of small crystallites resulting from the ordering of the polymeric chains at higher strain values as was confirmed by DSC measurements