Advanced composites in sailplane structures: Application and mechanical properties

Advanced Composites in sailplanes mean the use of carbon and aramid fibers in an epoxy matrix. Weight savings were in the range of 8 to 18% in comparison with glass fiber structures. The laminates will be produced by hand-layup techniques and all material tests were done with these materials. These values may be used for calculation of strength and stiffness, as well as for comparison of the materials to get a weight-optimum construction. Proposals for material-optimum construction are mentioned

Simulation of Material Properties Below the Debye Temperature: A Path-Integral Molecular Dynamics Case Study of Quartz

Classical and path integral molecular dynamics (PIMD) simulations are used to study alpha-quartz and beta-quartz in a large range of temperatures at zero external stress. PIMD account for quantum fluctuations of atomic vibrations, which can modify material properties at temperatures below the Debye temperature. The difference between classical and quantum mechanical results for bond lengths, bond angles, elastic modulii, and some dynamical properties is calculated and comparison to experimental data is done. Only quantum mechanical simulations are able to reflect the correct thermomechanical properties below room temperature. It is discussed in how far classical and PIMD simulations can be helpful in constructing improved potential energy surfaces for silica.Comment: 8 pages, 9 figures, submitted to J. Chem. Phy

Composite rotor blades for large wind energy installations

The design of large wind power systems in Germany is reviewed with attention given to elaboration of the total wind energy system, aerodynamic design of the rotor blade, and wind loading effects. Particular consideration is given to the development of composite glass fiber/plastic or carbon fiber/plastic rotor blades for such installations

Is Dry Cupping Therapy Effective for Non-Specific Chronic Neck Pain in Adults?

Objective: The objective of this selective Evidence Based Medicine (EBM) review is to determine whether or not “Dry Cupping Therapy is effective for non-specific chronic neck pain in adults?” Study Design: Review of 3 randomized controlled trials (RCT) Data Sources: All studies were published in peer-reviewed journals found in PubMed or Cochrane Database. Outcomes measured: Patients were divided into two groups, the experimental group or the control group. Patients in the experimental group received dry cupping therapy. Patients in the control group received no therapy at all, normal standard of care (physiotherapy, sports activities, analgesics), or progressive muscle relaxation. The primary outcome measured was chronic neck pain intensity at rest via a 11-NRS scale in one study, or a visual analog scale (VAS) of 0 mm to 100 mm in the other studies with 0 equaling no pain and 100 equaling the worst pain. In one study, patients were asked if they had experienced relief from pain by answering ‘yes’ or ‘no’ using an Adequate Relief Scale. A secondary outcome included chronic neck pain related to motion (VAS). In Cramer (2011) the VAS was 0 – 10 cm. For both measures, a baseline was measured before and after treatment. In all three RCTs, there was no long-term follow-up. Results: In two out of the three RCTs, (Cramer – 2011 and Lauche – 2011), results of dry cupping therapy vs control proved to cause a decrease in pain at rest and with motion and reached statistical significance (p ≤ 0.05). In Lauche 2013, the results showed that for every 5 people treated 1 person experienced relief from pain with cupping. Additional results showed there was not a statistically significant decrease in pain between cupping and progressive muscle relaxation therapy, but that there was a change from baseline for both. The studies did not follow long-term treatments, so its unknown if pain relief is lasting. Conclusions: Based off of the three reviewed RCTs in this paper, it is indeterminate whether or not dry cupping is effective for chronic non-specific neck pain