دكتوراه
هندسة
Swansea University
مجال التميز | تميز دراسي وبحثي |
البحوث المنشورة |
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البحث (1): | |
عنوان البحث: | Functionalised graphene effect on the mechanical and thermal properties of recycled PA6/PA6,6 blends |
رابط إلى البحث: | Click here |
تاريخ النشر: | 14/01/2021 |
موجز عن البحث: | Limiting the generation of polymers waste and maximizing their recyclability and recovery have been the main focus of the research and industry in recent years. Recycling of polyamides leads to the loss in mechanical and thermal properties, therefore, in order to reuse recycled nylons, an enhancement in their properties is desired. Enhancing the properties of recycled polyamides by the addition of functionalised graphene nanoparticles (GNPs) was the goal of this study. Recycled PA6/PA6,6 blends and functionalised graphene nanocomposites were prepared using hot-melt extrusion process. Two types of functionalised graphene were used: O2-GNPs and Amine-GNPs. The nanofillers didn’t affect the crystallinity of the recycled nylon, while the presence of functionalised graphene increased the thermal conductivity by enabling better heat transfer routes within the polymer. The microstructure of the materials was characterised confirming the successful dispersion but with a slight variation in GNPs/Polymer bonding depending on the functionalisation type. The strong nylon-to-graphene interfacial hydrogen bonding increased the mechanical properties of the recycled nylon nanocomposites. The functionalised nanoparticles slowed down the segmental motion of the polymer chain and decreased the ductility with increasing GNPs contents up to 10 wt%. The overall behaviour of recycled nylon nanocomposites showed dependency on the type of functionalisation and concentration of GNPs with better improvement in the overall properties using 2 wt% Amine-GNPs. These enhanced properties make functionalised graphene/recycled nylon nanocomposites a promising new class of advanced materials. |
البحث (2): | |
عنوان البحث: | Deployment of Tactical Mobile Networks |
رابط إلى البحث: | Click here |
تاريخ النشر: | 27/06/2020 |
موجز عن البحث: | Tactical mobile networks are at the forefront of military communication systems during military missions and in digitalized battlefields, and they can be also used for disaster recovery and rescue missions. These networks serve diverse range of applications to users with different mobility patterns and operate under adverse radio propagation conditions. They are highly dynamic and heterogeneous and must provide minimum level of connectivity and coverage without any supporting infrastructure. This makes their design and deployment much more challenging with much stringent requirements than for other types of mobile communication networks. As the complexity of telecommunication systems has increased together with many intricate relationships among various stakeholders, the selection and usage of network metrics has become much more important. Network metrics are crucial to define key performance indicators (KPIs) and service quality levels whilst some metrics have been standardized. Common telecommunication metrics have been reviewed and then specialised for tactical networks to understand different trade-offs such as reliable coverage versus quality of service. The collected metrics were then sorted into several main categories with majority of these metrics being either related to evaluating the system performance or evaluating the user experience. |
البحث (3): | |
عنوان البحث: |
Reliable Metrics and Deployment Issues of Tactical ad-hoc Networks |
رابط إلى البحث: | Click here |
تاريخ النشر: | 03/03/2020 |
موجز عن البحث: | The mobile tactical network (MTN) utilized for wireless military communications networks are classified as MANETS. Modern tactical communication systems are highly heterogeneous dynamic networks interconnecting many different types of users. Involving personnel, vehicles, sensors, devices and other connected equipment, the users have vastly different communication requirements while co-existing in smaller or larger geographical proximity. Unlike their commercial counterparts, MTNs pose unique characteristics with restricted bandwidth. Thus, the commercial vendors of ICT equipment do not have sufficient experience or capabilities to deliver military grade products. Rather, modification of commercial product by the original providers or third-party vendors to meet the battlefield requirements is frequently common. Comprehensive comparison of the performance and design characteristics of the commercial MANETs and their military counterparts was carried out using NS2 simulations. It was found that for scenarios requiring long-range connectivity, hierarchical routing protocols give the most accurate performance predictions for MTNs. Further, it is necessary to consider the sizes of various military units, different topology area size, warfighting platforms and combat mission types. Finally, it is argued that many commercial off-the-shelf (COTS) technologies can be adopted for their use in MTNs, even though it requires a lot of additional efforts to overcome challenges not considered by the commercial solutions. |
البحث (4): | |
عنوان البحث: | MANETs in Military Communications Design Concepts and Challenges |
رابط إلى البحث: | |
تاريخ النشر: | 04/2019 |
موجز عن البحث: | The mobile tactical network (MTN) utilized for wireless military communications networks are classified as MANETS. Modern tactical communication systems are highly heterogeneous dynamic networks interconnecting many different types of users. Involving personnel, vehicles, sensors, devices and other connected equipment, the users have vastly different communication requirements while co-existing in smaller or larger geographical proximity. Unlike their commercial counterparts, MTNs pose unique characteristics with restricted bandwidth. Thus, the commercial vendors of ICT equipment do not have sufficient experience or capabilities to deliver military grade products. Rather, modification of commercial product by the original providers or third-party vendors to meet the battlefield requirements is frequently common. Comprehensive comparison of the performance and design characteristics of the commercial MANETs and their military counterparts was carried out using NS2 simulations. It was found that for scenarios requiring long-range connectivity, hierarchical routing protocols give the most accurate performance predictions for MTNs. Further, it is necessary to consider the sizes of various military units, different topology area size, warfighting platforms and combat mission types. Finally, it is argued that many commercial off-the-shelf (COTS) technologies can be adopted for their use in MTNs, even though it requires a lot of additional efforts to overcome challenges not considered by the commercial solutions. |