Expanded Graphite–Epoxy–Flexible Silica Composite Bipolar Plates for PEM Fuel Cells

Silica impregnated expanded graphite–epoxy composites are developed as bipolar plates for proton exchange membrane (PEM) fuel cells. These composite plates were prepared by solution impregnation, followed by compression molding and curing. Mechanical properties, electrical conductivities, corrosion resistance, and contact angles were determined as a function of impregnated content. The plates show high flexural strength with 5% methyltrimethoxysilane (MTMS) addition (20 MPa) and in‐plane conductivity of 131 S cm⁻¹ that meet the DOE target (>100 S cm⁻¹). Corrosion current values as low as 1.09 μA cm⁻² were obtained. The contact angle was found to be 80°. Power density of 1 W cm⁻² was achieved with custom made expanded graphite–polymer composite plates. High efficiency values were obtained at low current regions.     

Exciton diffusion exceeding 1μm:run,exciton,run!

Exciton diffusion lengths reaching the micrometer length scale have long been desired in solution-processed semiconductors but have remained unattainable using conventional materials to date.Now halide perovskite nanocrystal films show unprecedented exciton migration with diffusion lengths approaching 1μm owing to the efficient combination of radiative and nonradiative energy transfer.     

Investigation of Wear and Corrosion Behaviors of Ti15Mo Alloy Produced by Mechanical Alloying Method in SBF Environment

Powder Metallurgy and Metal Ceramics - This study aims to examine the wear performance and electrochemical corrosion properties of Ti15Mo alloy produced by mechanical alloying (MA) in simulated...     

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey,depending on climatic changes

Virgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty-six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta-7-stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta-7-stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm-based inverse least squares method to determine whether there is a relationship between climate data and delta-7-stigmastenol values. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.     

The Role of Zirconium on the Microstructure and Electrochemical Corrosion in TZM Alloys

Protection of Metals and Physical Chemistry of Surfaces - In this paper, Mo-based titanium–zirconium (TZM) alloys containing 0.06, 0.07, 0.08 and 0.09% Zr were produced by mechanical alloying...