On the formulation and implementation of geometric and manufacturing constraints in node–based shape optimization

We introduce a novel method to handle geometrical and manufacturing constraints in parameter–free shape optimization. Therefore the design node coordinates are split in two sets where one set is declared as new design variables and the other set is coupled to the new design variables such that the geometrical constraint is fulfilled. Thereby no additional equations are appended to the optimization problem. In contrast the implementation of a demolding constraint is presented by formulating inequality constraints which indeed have to be attached to the optimization problem. In the context of a sensitivity–based shape optimization approach all manufacturing constraints have to be formulated in terms of the finite element node coordinates such that first order gradients with respect to the design node coordinates can be derived.     

Über den Effekt von Schwefel- und Teerzusätzen zu Kopfwaschmitteln auf die Seborrhoea capitis

Effect of Incorporating Sulfur and Tar in Hair Shampoos on Seborrhoea Capitis Twenty experimental persons were subjected to shampooing with a 6% solution of the sodium salt of polyethyleneglycollaurylether sulfate and with the same solution to which 2.5% colloidal sulfur and 1.5% coal tar distillate respectively were added. Lipids of the scalp and hair determined prior to shampooing, immediately after shampooing, as well as 2 and 5 days after shampooing. No evidence was found which might indicate that the incorporation of colloidal sulfur or coal tar distillate to shampoos significantly retards the fattening of scalp and hair after one single shampooing.     

Maximising low voltage grid hosting capacity for PV and electric mobility by distributed voltage control

European low voltage grids host an increasing amount of energy from rooftop PV installations. Experience in Germany has shown that PV installations do not grow uniformly but with regional hot spots. Meanwhile it is widely agreed that low voltage grids should only be updated to accommodate some 90 % or less of available PV power in peak times in order to avoid extensive costs for grid reinforcement. The main limiting factor in rural distribution grids is the grid voltage. In the Austrian research project “DG DemoNet—Smart LV Grid” new approaches to deal with restricted grid capacities are analysed using active voltage control. In three pilot regions, the actual amount of installed PV is increased to reach physical limits. Voltage control schemes are developed, tested in simulations and then validated in the field. In one pilot region, electric mobility as additional future load in low voltage grids and its integration into the overall system is considered. This paper analyses the performance of the developed control approaches in simulation.     

Discoid lateral meniscus in children. Long-term follow-up after total meniscectomy

We retrospectively reviewed the long-term results of total meniscectomy performed in seventeen knees (fourteen children) to treat a discoid lateral meniscus. The mean duration of follow-up was 19.8 years (range, 12.5 to 26.0 years). On the basis of the rating system of the International Knee Documentation Committee, seven knees were normal (grade A), six were nearly normal (grade B), three were abnormal (grade C), and one was severely abnormal (grade D) at the latest follow-up evaluation. Ten of the seventeen knees had clinical symptoms of osteoarthrosis. Radiographs were available for fifteen of the knees at the latest follow-up evaluation. Eleven of the treated knees could be compared with the uninvolved, contralateral knee. Ten knees had osteoarthrotic changes, such as flattening of the lateral femoral condyle, formation of a ridge along the lateral femoral condyle, and spurring and sclerosis of the tibial plateau. Osteochondritis dissecans developed in two knees, nine and twenty years after the initial meniscectomy.     

Anfälligkeit gewindeformender Schrauben aus korrosionsbeständigen Stählen gegenüber Spannungsrisskorrosion

Susceptibility of thread‐forming screws made from stainless steels with relation to stress corrosion cracking Thread‐forming screws, manufactured from martensitic and austenitic stainless steels, were tested concerning their susceptibility with relation to stress corrosion cracking. Based as closely on application usage as possible, testing comprised using the fasteners to clamp steel sheets of different material types at changing corrosion conditions according to DIN 50021‐SS and DIN 50018‐KWF 2,0S. During the exposure until 90% of the martensitic drilling screws had failed due to hydrogen‐induced stress corrosion cracking. Such fasteners represent a safety risk in building practice, even if corrosion resistance requirements are minimal. The screws made of austenitic materials bore the identical test conditions without cracking.     

Discrete synchronous multifocal osteoid osteoma of the humerus

A 24-year-old patient is described who had a 4-year history of pain in the right upper arm, with distinct night pain, that responded to salicylates. From the findings on conventional radiography, bone scintigraphy and MRI a multifocal osteoid osteoma was suspected, with one focus in the cancellous region of the greater tuberosity and a second cortical focus at the proximal humeral diaphysis. The resection "en bloc" of both tumors and histological examination confirmed the diagnosis. The patient was painfree after the curative resection of the two osteoid osteomas. Osteoid osteoma is a frequently found benign bone tumor, accounting for approximately 11% of cases. In rare cases a multicentric occurrence has been described. A possible occurrence of more than one osteoid osteoma in a single bone, not verified histologically, has been reported only three times in the literature. In patients with scintigraphic and radiographic findings of two foci, discrete synchronous multifocal osteoid osteomas should be suspected.