Characterization of Commercial Polymer–Carbon Composite Bipolar Plates Used in PEM Fuel Cells

Bipolar plates represent a crucial component of the PEM fuel cell stack. Polymer–carbon composites are recognized as state-of-the-art materials for bipolar plate manufacturing, but their use involves a compromise between electrical and heat conductivity, mechanical strength and costs. Thus, all key parameters must be considered when selecting a suitable plate satisfying the demands of the desired application. However, data relevant to commercial materials for such selection are scarce in the open literature. To address this issue, 13 commercially available polymer–carbon composites are characterised in terms of the following parameters: through-plane conductivity, hydrogen permeability, mechanical strength, water uptake, density, water contact angle and chemical stability. None of the materials tested reached the DOE target for electrical conductivity, while five of the materials met the target for flexural strength. The overall best-performing material showed a conductivity value of 50.4 S·cm−1 and flexural strength of 40.1 MPa. The data collected provide important supporting information in selecting the materials most suitable for the desired application. In addition, the key parameters determined for each bipolar plate supply important input parameters for the mathematical modelling of fuel cells

Polyolefin composite with enhanced processing properties

Polyolefinický kompozit se zlepšenými zpracovatelskými vlastnostmi obsahuje vedle základní polymerní složky tvořené polyolefinem přídavek multifunkčního aluminosilikátového aditiva se synergickými účinky taveninu ztužujícího plniva a nukleačního činidla na bázi jílu upraveného vyluhováním v HCl, přičemž toto aditivum je v kompozitní směsi obsaženo v množství 0,5 až 10 % hmotnostních a velikost jeho částic nepřesahuje 50 .mi.m. Je vhodný zejména pro výrobu lehčených polyolefinů se zjemněnou lehčenou strukturou a zlepšenými mechanickými vlastnostmi v energeticky úspornějším režimu.In the present invention, there is disclosed a polyolefin composite with enhanced processing properties comprising in addition to the base polymer component formed by polyolefin addition of multifunctional alumosilicate additive exhibiting synergistic properties, a melt of stiffening filler and a clay-based nucleation agent treated by leaching in HCl, whereby the additive is comprised in the composite mixture in an amount in the range of 0.5 to 10 percent by weight and particle size thereof is not greater than 50 microns. The so prepared polyolefin composite is particularly suitable for the preparation of lightweight polyolefins with finer expanded structure and enhanced mechanical properties in energy-saving mode

Chronic kidney disease and polypharmacy as risk factors for recurrent falls in a nursing home population

Abstract Background It is known that nursing home patients who have sustained a previous fall are at a higher average risk for recurrent falls. Therefore, these patients require closer attention and monitoring for fall prevention. Methods We conducted a retrospective review in our Level 1 Trauma Center, who sustained a ground‐level fall in a nursing home from January 2017 to December 2018. Inclusion criteria involved patients aged 65 or older, admitted from nursing homes. Logistic regression analysis was performed to identify factors associated with recurrent fall. Results A total of 445 patients were identified. Among them, 47 (10.6%) patients sustained recurrent falls, The median age was 83.3 years old and. The recurrent fall group was more likely to have chronic kidney disease (CKD) (27.1% vs. 13.1%, p = 0.02) and diabetes (47.9% vs. 31%, p = 0.02). The median number of medications taken by a patient was 8.78. Overall, 176 (39.5%) patients sustained any injury, and 25 (5.6%) patients died within the study period. The presence of CKD (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.15–4.76, p = 0.02) and polypharmacy (number of medications of 9 or above) (OR, 2.07; 95% CI, 1.12–3.82, p = 0.02) were independent risk factors for recurrent falls. Conclusions CKD and polypharmacy were associated with a risk of recurrent falls among nursing home patients. The incidence of falls has a multifactorial etiology, and it is important to identify such risk factors to better prevent the morbidities and mortalities associated with fall‐related injuries

Cardiovascular Efficacy and Safety of Bococizumab in High-Risk Patients

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