Abstract:The optimal power flow (OPF) problem is a non-linear and non-smooth optimization problem. OPF problem is a complicated optimization problem, especially when considering the system constraints. This paper proposes a new enhanced version for the grey wolf optimization technique called Developed Grey Wolf Optimizer (DGWO) to solve the optimal power flow (OPF) problem by an efficient way. Although the GWO is an efficient technique, it may be prone to stagnate at local optima for some cases due to the insufficient diversity of wolves, hence the DGWO algorithm is proposed for improving the search capabilities of this optimizer. The DGWO is based on enhancing the exploration process by applying a random mutation to increase the diversity of population, while an exploitation process is enhanced by updating the position of populations in spiral path around the best solution. An adaptive operator is employed in DGWO to find a balance between the exploration and exploitation phases during the iterative process. The considered objective functions are quadratic fuel cost minimization, piecewise quadratic cost minimization, and quadratic fuel cost minimization considering the valve point effect. The DGWO is validated using the standard IEEE 30-bus test system. The obtained results showed the effectiveness and superiority of DGWO for solving the OPF problem compared with the other well-known meta-heuristic techniques.

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Objective: this study aimed to evaluate the effect of local injection of vitamin D 1, 25 Dihydroxycholecalciferol (VD) by means of measuring OTM and bone density by computerized tomography the number of osteoclasts during orthodontic relapse in uremic New Zealand rabbits after induced nephropathy. Materials and Methods: This study is in vivo experimental research. A total of 34 male New Zealand rabbits were used in the study, which were randomly split into three groups, control group (CG), uremic group(CKD G) and uremic with locally injected VD (CKD with VD G). All rabbits were given an orthodontic force of 60 cN using a NITI 3spin coil spring that was activated for 15-18 days and then conditioned to be passive. Through this phase, the CKD with VD group was locally injected with VD once every week for 4 weeks. CT measurements and histological analysis were formed at 18 days, after removal of the Orthodontic appliances and after 38 days, Data were analyzed statistically using an independent t-test (p < 0.05). Results: The post OTRM was significantly lower in the CKD with VD injection than in the CKD (P=0.01). The number of osteoclasts in the CKD with VD group was significantly lower than that in the CKD group (p = 0.021). Conclusion: locally injected VD can prevent post orthodontic tooth relapse movement by suppressing osteoclastogenesis and decreasing osteoclasts number in uremic rabbits.