The integration of photovoltaic and battery energy storage systems into utility grids is favorable for electricity customers, especially for high consumption load patterns due to the high electricity bill. To increase the annual bill savings and decrease the dependency on the utility grid, a procedure of optimally sizing the PV battery system is presented in this paper. A MATLAB-based code of the genetic algorithm is used to maximize the system self-sufficiency and minimize the discounted payback period while guaranteeing the system profitability. The optimization technique is introduced under the time-of-use tariff structure for residential prosumers in two scenarios. The first introduces a sellback energy price equal to the off-peak energy price, and the second introduces a sellback energy price equal to the on-peak energy price. The economic and technical effects of this optimization are described and analyzed. The effect of PV system capital cost, battery capital cost, and discount rate variations is evaluated by sensitivity analysis. The results indicate that for a sellback price equal to the off-peak price, a minimum discounted payback period can be achieved by installing the maximum PV system size without batteries, and it is reduced to half of its value for a sellback price equal to the on-peak price at the same PV system capacity. For a sellback price equal to the off-peak price, the minimum DPBP of 5.8 years can be achieved by installing a 20 kW _p PV system without batteries with 47% self-sufficiency and 2.4 years for a sellback price equal to the on-peak price by installing the same system capacity. The proposed approach highlights that increasing the battery size leads to high self-sufficiency without a considerable decrease in the annual bill savings that encourage customers to invest in the PV battery system.

Dynamic pricing is one of the most important tools to achieve demand side management in smart grids. It dynamically adjusts the price of the electricity consumed by the end users according to various utilization timing conditions. Different dynamic pricing schemes can be submitted to different consumers, including industrial users and residential households. The selection then the implementation of the appropriate dynamic pricing scheme is required for proper enhancement of the consumers electrical load profile as required by demand side management systems. This paper highlights the dynamic pricing concept by surveying its different schemes and their related research work in a chronological order. The paper is ended by detailed subjective comparison between dynamic pricing schemes to evaluate their effectiveness in different smart grid applications. The main benefit of the resultant comparison is to be used as a benchmark specifying the suitable dynamic pricing scheme for both utility and consumers, while considering the present and the upcoming future opportunities for utility infra-structure and operation conditions.

Hirschsprung associated enterocolitis (HAEC) is a common and sometimes life-threatening complication of Hirschsprung disease (HSD). Presenting either before or after definitive surgery for HSD, it may manifest clinically as abdominal distension and explosive diarrhea, along with emesis, fever, lethargy and even shock. The pathogenesis of HAEC involves a complex interplay between a dysfunctional enteric nervous system, abnormal mucin production, insufficient immunoglobulin secretion and unbalanced intestinal microflora. Early recognition of HAEC and preventive practices such as rectal wash outs following a pull through can lead to improved outcomes. Treatment strategies for acute HAEC include timely resuscitation, colonic decompression and antibiotics. Recurrent or persistent HAEC requires evaluation for mechanical obstruction or residual aganglionosis and may require surgical treatment with posterior myectomy or redo pull through.Aim of work:This study aimed to evaluate HAEC as a postoperative complication in children who were admitted after pull-through regarding the type of surgery, incidence, clinical presentation, sepsis workup, and management in Alexandria University Children’s Hospital at El- Shatby.