基于元启发式算法的船舶动力装置随机建模与性能优化

For the successful operation of any industry or plant continuous availability of power supply is essential.Many of the large-scale plants established their power generation units.Marine power plant having two generators is also fall in this category.In this study,an effort is made to derive and optimize the availability of a marine power plant having two generators,one switch board and distribution switchboards.For this purpose,a mathematical model is proposed using Markov birth death process by considering exponentially distributed failure and repair rates of all the subsystems.The availability expression of marine power plant is derived.Metaheuristic algorithms namely dragonfly algorithm(DA),bat algorithm(BA)and whale optimization(WOA)are employed to optimize the availability of marine power plant.It is revealed that whale optimization algorithm outperforms over dragonfly algorithm(DA),and bat algorithm(BA)in optimum availability prediction and parameter estimation.The numerical values of the availability and estimated parameters are appended as numerical results.The derived results can be utilized in development of maintenance strategies of marine power plants and to carry out design modifications.

Implant biomaterials: A comprehensive review

Appropriate selection of the implant biomaterial is a key factor for long term success of implants. The biologic environment does not accept completely any material so to optimize biologic performance, implants should be selected to reduce the negative biologic response while maintaining adequate function. Every clinician should always gain a thorough knowledge about thedifferent biomaterials used for the dental implants. This article makes an effort to summarize various dental biomaterials which were used in the past and as well as the latest material used now.

Oral rehabilitation of a Parkinson's patient:A case report

Parkinson's disease is an idiopathic disorder of the central nervous system, characterized by resting tremors, muscular rigidity, slow and decreased movements. Oral rehabilitation of these patients requires special care, especially in those cases where the patient's socioeconomic status is not good and patient cannot come several times for fabrication of a complete denture. This clinical report presents a case of a Parkinson's patient who was completely rehabilitated in 3 appointments using special techniques. Border molding, f inal impression and jaw relation procedures were done in one appointment by using a custom tray with detachable handles and occlusal rims.

Priming the tooth surface with chlorhexidine and antibacterial activity of resin cement

AIM: To evaluate the effect of priming the tooth surface with 2% chlorhexidine gluconate on antibacteria activity of resin cement. METHODS: Ten patients in whom a single missing tooth was present on both the right and left side in the upper or lower arch were selected. Two fixed partia dentures(FPDs) in each patient on the right and left side were planned. Each FPD was assigned either to the control or test group. In the control group, FPD was luted with resin cement and in the test group, the tooth surface was primed with 2% chlorhexidine gluconate before luting with resin cement. Bacteriological samples were collected at base line level, as the patient came to the outpatient department before the start of any treatment, 5 wk prior to cementation of FPD and at 13 wk(8wk after final cementation). Microbiological processing of all samples was done and the results were statistically analyzed. RESULTS: In the test group, a predominance of aerobic/facultative gram positive cocci rod was seen which indicates a healthy periodontal site, whereas in thecontrol group, a predominance of anaerobic gram negative rods was present which indicates an unhealthy periodontal condition. This is evident by the fact that the anaerobic bacteria percentage in the control sample is 57% and 15% in the test sample after 13 wk, whereas the aerobic/facultative bacteria percentage is 43% in the control sample and 85% in the test sample after 13 wk. The percentage of gram negative bacteria in the control sample is 61% and in the test sample is 20% after 13 wk, whereas the percentage of gram positive bacteria in the control sample is 39% and in the test sample is 80% after 13 wk. The shift from anaerobic gram negative bacteria to aerobic gram positive bacteria is clearly seen from the control to test sample after 13 wk. CONCLUSION: The present study demonstrated that priming the tooth surface with 2% chlorhexidine gluconate may enhance antibacterial activity of the resin cement.