The effect of rotational inertia on the squeeze film load between porous annular curved plates

The squeeze film behaviour between rotating annular plates was analysed theoretically for the case when the curved upper plate with a uniform porous facing approached normally the impermeable flat lower plate. Expressions for the pressure and the load capacity were obtained. The load capacity decreased when the speed of rotation of the upper disc increased up to a certain value $\text{B}\text{?}{}_0$ of the curvature parameter $\text{B}\text{?}$. This trend was reversed for $\text{B}\text{?}\text{?}\text{B}\text{?}{}_0$. The load capacity could be increased without altering the speed of rotation by increasing $\text{B}\text{?}$.     

A Bayesian game model and network availability model for small cells under denial of service (DoS) attack in 5G wireless communication network

Wireless Networks - Nowadays small cells have become the integral part of 5G wireless communication network (WCN). However, the incorporation of small cells in 5G WCN creates chances for attackers...     

Smart antenna design for high‐speed moving vehicles with minimum return loss

The Internet of Things (IoT) is a connection amongst people and applications to another dimension of machine‐to‐machine communication. IoT scenario is unequivocally related with the development of the advancement of wireless sensor systems (WSNs) and radio‐frequency identification (RFID) frameworks. Owing to the technological advances around the world, energy demand is increasing exponentially. Energy proficiency has turned out to be one of the real worries in the present life that essentially influence every single human action. In communication system, return loss is a major issue for transmission process. Owing to return loss, a huge amount of power consumption occurs. This phenomenon is contemporary with transmission process, and it will initiate a serious problem for high‐speed moving substance like aircraft, rockets, and spaceship. To overcome this problem, a four‐element cylindrical antenna (conformal) array with better axial radiation is proposed. The four U‐shaped slots are uniformly wrapped around on a cylindrical surface, which produces tilted radiation. To enhance the axial radiation, four conformal elements are reefed by a one‐ to four‐microstrip feed network. The proposed conformal design has a bandwidth of 200 MHz (narrow bandwidth) at the center frequency of 3.9 GHz, covering the range of 3 to 3.9 GHz, with the gain of 4.9 dBic, and can be suitable for unmanned aerial vehicles (UAV), wireless avionics intra‐communication (WAIC), and so forth. The proposed design is low profile and can be used for high‐speed avionic applications. Finally, machine learning technique is explored to design a model for a smart antenna with optimistic parameters to reduce return loss and enhance the transmission rate.     

Organic Long-Persistent Luminescence from a Thermally Activated Delayed Fluorescence Compound

Organic long-persistent luminescence (OLPL) is one of the most promising methods for long-lived-emission applications. However, present room-temperature OLPL emitters are mainly based on a bimolecular exciplex system which usually needs an expensive small molecule such as 2,8-bis(diphenyl-phosphoryl)dibenzo[b,d]thiophene (PPT) as the acceptor. In this study, a new thermally activated delayed fluorescence (TADF) compound, 3-(4-(9H-carbazol-9-yl)phenyl)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (CzPhAP), is designed, which also shows OLPL in many well-known hosts such as PPT, 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi), and poly(methyl methacrylate) (PMMA), without any exciplex formation, and its OLPL duration reaches more than 1 h at room temperature. Combining the low cost of PMMA manufacture and flexible designs of TADF molecules, pure organic, large-scale, color tunable, and low-cost room-temperature OLPL applications become possible. Moreover, it is found that the onset of the 77 K afterglow spectra from a TADF-emitter-doped film is not necessarily reliable for determining the lowest triplet state energy level. This is because in some TADF-emitter-doped films, optical excitation can generate charges (electron and holes) that can later recombine to form singlet excitons during the phosphorescence spectrum measurement. The spectrum taken in the phosphorescence time window at low temperature may consequently consist of both singlet and triplet emission.     

Improve Performance of Wireless Sensor Network Clustering Using Mobile Relay

Wireless Personal Communications - Wireless sensor networks sense events, collect data and forward it to the infrastructural node, called sink, for further processing and assessment. The...     

Cooperative Spectrum Sensing Optimization Using Meta-heuristic Algorithms

Wireless Personal Communications - Spectrum sensing helps to sense the unutilized spectrum in an opportunistic manner for cognitive radios. The various cognitive radios work in a cooperative manner...     

Transmission of Audio over LTE Packet Based Wireless Networks Using Wavelets

Wireless Personal Communications - One of the recent trends of networking and mobile technology is mobile cloud computing (MCC) that provides rich computational, storage resources and services in...     

Performance Analysis of MSFRLS-VFF Based Real-Time Adaptive Noise Canceller with RLS and APA Algorithms Using TMS320C6713 Processor

Wireless Personal Communications - In this paper, the real-time adaptive noise canceller (ANC) system is implemented using modified sigmoid function variation based recursive least square with...