No abstract

In the course of the “Energiewende,” the German electricity market is undergoing major changes. The state-aided priority of renewable generation has led to a significant decline in electricity prices. This reduces the profit margin of cogeneration units and increases the necessity of flexible operation to avoid electricity production when spot prices drop below marginal costs. In this work, a 100 MWel combined-cycle (CC) power plant supplying heat and power to a paper mill is investigated. Currently, the plant is operated heat-controlled and is therefore unable to react to changing electricity spot prices. With the integration of heat storage, the plant is enabled to switch to power-controlled mode. To evaluate the technical impact of the storage, the plant and a thermochemical MgO/Mg(OH)2 storage are modeled using the stationary process simulation tool ebsilon professional. Different operation modes are investigated and results are used to derive a mixed integer linear programming (MILP) model to optimize the operation of the plant/storage system. Using this method, the overall economic impact of the storage on the plant operation is quantified.

Obviously, the early postoperative advantages of the minimal invasive approach provide for an improved re-establishment of symmetry and load. In this clinical course study, the proof is validated because the trends in the biomechanical gait parameters are comparable by means of gait velocity standardisation.

Use of the minimally invasive Watson-Jones approach shows advantages compared with the transgluteal Bauer approach 6 and 12 weeks postoperatively. Up to now there has been no prospective randomized clinical study that has definitely shown the superiority of the minimally invasive procedure. For that reason, the conventional approaches in THR are still the gold standard.

The indecation and the efficacy of antibiotic prophylaxis in endoprosthetic operations are discussed with reference to prospective studies. After parenteral administration of 80 mg gentamicin the antibiotic concentrations in the serum and in the wound exudate were studied for 2 to 6 hrs after administration. During this observation period the gentamicin concentrations in the wound exudate were about equal to those in the serum. A comparison of the concentrations after parenteral and after local administration of gentamicin showed much higher concentrations in the wound exudate when gentamicin was administered with the bone cement.