Piezoelectric Energy Harvesting Based on Bi-Stable Composite Laminate

Energy harvesting employing nonlinear systems offers considerable advantages comparing to linear systems in the field of broadband energy harvesting. Bi-stable piezoelectric energy harvesters have been proved to be a good candidate for broadband frequency harvesting due to their highly geometrically nonlinear response during vibrations. These bi-stable energy harvesters consist of bi-stable structure and piezoelectric transducers. The nonlinear response depends on the host bi-stable structure. A possible category of bi-stable structures is bi-stable composite laminate, which has two stable equilibrium states resulting from the mismatch in thermal expansion coefficients between plies. It has received considerable interest in deformable structure since the “snap-through” between two stable states results in a significant deformation without continuous energy supply. Combining piezoelectric transducer and the bi-stable composite laminate is a feasible method to obtain bi-stable energy harvester. Piezoelectric energy harvesters based on bi-stable composite laminate have been shown to exhibit high levels of power output over a wide range of frequencies. This chapter aims to summarize and review the various approaches in piezoelectric energy harvesting based on bi-stable composite laminates

A Multiobjective Computation Offloading Algorithm for Mobile Edge Computing

In mobile edge computing (MEC), smart mobile devices (SMDs) with limited computation resources and battery lifetime can offload their computing-intensive tasks to MEC servers, thus to enhance the computing capability and reduce the energy consumption of SMDs. Nevertheless, offloading tasks to the edge incurs additional transmission time and thus higher execution delay. This paper studies the trade-off between the completion time of applications and the energy consumption of SMDs in MEC networks. The problem is formulated as a multiobjective computation offloading problem (MCOP), where the task precedence, i.e. ordering of tasks in SMD applications, is introduced as a new constraint in the MCOP. An improved multiobjective evolutionary algorithm based on decomposition (MOEA/D) with two performance enhancing schemes is proposed.1) The problem-specific population initialization scheme uses a latency-based execution location initialization method to initialize the execution location (i.e. either local SMD or MEC server) for each task. 2) The dynamic voltage and frequency scaling based energy conservation scheme helps to decrease the energy consumption without increasing the completion time of applications. The simulation results clearly demonstrate that the proposed algorithm outperforms a number of state-of-the-art heuristics and meta-heuristics in terms of the convergence and diversity of the obtained nondominated solutions

Simulation and reliability analysis of a flexible manufacturing system with AGV based material handling

This thesis investigates the reliability of a flexible manufacturing system with AGV based material handling. An analytical model was built using the stale space approach (Markov process). Although the method is shown to be tedious when the number of system compon ents becomes large , however , it does provide a powerful approach for reliability analysis of complex systems such as flexible manufacturing facilities. To simplify the analysis, state merging and state truncating techniques were used in carrying out the calculations. To compare with the analytical results, a simulation model was built using SLAM II discrete event modelling and simulation software. The results were very close to the analytical ones when same failure and repair rates were assumed 11r the basic components of the system. Overall, it was found that the simulation method was much simpler to develop and experiment with. A SLAM II simulation model of the system performance was also built to examine the operation of the FMS as a whole with failure and repair events.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

A novel design and manufacturing method for compliant bistable structure with dissipated energy feature

In this paper, a novel design concept and manufacturing method for the compliant bistable structure is proposed. The pulsed laser technique is utilized as the manufacturing method for both the fabrication and the introduction of desired pre-stresses, simultaneously. Based on this concept, a novel bistable structure consisted of one pre-compressed main beam, and a pair of supporting beams is designed and fabricated. The deformation difference between the main beam and the supporting beams induced by laser heating residual stress make the main beam to buckle under the constraints of two supporting beams and possess a bistable feature. The bistable structures can be implemented into other devices in the form of cantilevers thanks to the internal integration of the buckled beam and the boundary conditions. The characteristics of this new bistable structure, including its stable shape and snap-through response, are investigated both experimentally and numerically. During the snap forth and back process with the snapping load of 19 mN and the required energy of 77 mN·mm, an impressive energy dissipation with a loss factor value of 0.3 exists. Finally, a parametric study was carried out to find the critical performance parameters.</p

A novel design and manufacturing method for compliant bistable structure with dissipated energy feature

In this paper, a novel design concept and manufacturing method for the compliant bistable structure is proposed. The pulsed laser technique is utilized as the manufacturing method for both the fabrication and the introduction of desired pre-stresses, simultaneously. Based on this concept, a novel bistable structure consisted of one pre-compressed main beam, and a pair of supporting beams is designed and fabricated. The deformation difference between the main beam and the supporting beams induced by laser heating residual stress make the main beam to buckle under the constraints of two supporting beams and possess a bistable feature. The bistable structures can be implemented into other devices in the form of cantilevers thanks to the internal integration of the buckled beam and the boundary conditions. The characteristics of this new bistable structure, including its stable shape and snap-through response, are investigated both experimentally and numerically. During the snap forth and back process with the snapping load of 19 mN and the required energy of 77 mN·mm, an impressive energy dissipation with a loss factor value of 0.3 exists. Finally, a parametric study was carried out to find the critical performance parameters.Mechatronic Systems Desig

Evaluation of efficacy and safety for Brucea javanica oil emulsion in the control of the malignant pleural effusions via thoracic perfusion

Abstract Background Brucea javanica oil emulsion (BJOE) is traditional Chinese medicine with implicated anti-tumor activity, which has been used for treating lung cancer in China. The aim of this investigation was to evaluate the effects and safety of intrapleural injection of BJOE in treating malignant pleural effusion (MPE). Methods The randomised controlled trials (RCTs) on the effects and safety of BJOE in treating MPE were searched from electronic medical database including MEDLINE, SCI, EMBASE, Cochrance Library and CNKI. A total of 14 RCTs with 1085 patients were involved in this meta-analysis. Results The overall response rate (ORR) of traditional chemotherapy drugs plus BJOE was higher than that of traditional chemotherapy drugs alone (p = 0.001; odds ratio = 1.39). Meanwhile, the combination of BJOE and traditional chemotherapy drugs improved the quality of life (QOL) of patients with MPE (p < 0.001; odds ratio = 1.56) compared with traditional chemotherapy drugs alone. Moreover, the participation of BJOE reduced the myelotoxicity and digestive reactions caused by traditional chemotherapy drugs (p < 0.05). Conclusions The efficacy and safety of traditional chemotherapy drugs plus BJOE was superior to traditional chemotherapy drugs alone via intrapleural injection in controlling MPE, which suggested that BJOE can be used to treat MPE

Structure-based virtual screening and molecular dynamics of potential inhibitors targeting sodium-bile acid co-transporter of carcinogenic liver fluke Clonorchis sinensis.

BackgroundClonorchis sinensis requires bile acid transporters as this fluke inhabits bile juice-filled biliary ducts, which provide an extreme environment. Clonorchis sinensis sodium-bile acid co-transporter (CsSBAT) is indispensable for the fluke's survival in the final host, as it circulates taurocholate and prevents bile toxicity in the fluke; hence, it is recognized as a useful drug target.Methodology and principal findingsIn the present study, using structure-based virtual screening approach, we presented inhibitor candidates targeting a bile acid-binding pocket of CsSBAT. CsSBAT models were built using tertiary structure modeling based on a bile acid transporter template (PDB ID: 3zuy and 4n7x) and were applied into AutoDock Vina for competitive docking simulation. First, potential compounds were identified from PubChem (holding more than 100,000 compounds) by applying three criteria: i) interacting more favorably with CsSBAT than with a human homolog, ii) intimate interaction to the inward- and outward-facing conformational states, iii) binding with CsSBAT preferably to natural bile acids. Second, two compounds were identified following the Lipinski's rule of five. Third, other two compounds of molecular weight higher than 500 Da (Mr > 500 Da) were presumed to efficiently block the transporter via a feasible rational screening strategy. Of these candidates, compound 9806452 exhibited the least hepatotoxicity that may enhance drug-likeness properties.ConclusionsIt is proposed that compound 9806452 act as a potential inhibitor toward CsSBAT and further studies are warranted for drug development process against clonorchiasis