Structure modification of La9.33Si6O26 (LSO) as SOFC electrolyte via a bi-doping mechanism provides enhanced electrical properties of La7.83Bi1.5Si5.7Sn0.3O26 at 873 K (1.84 × 10−2 S cm−1) with low activation energy of 0.80 eV compared to pristine LSO (0.08 × 10−2 S cm−1).
Syphilis is a sexually transmitted disease caused by Treponema pallidum. The signs and symptoms of syphilis vary depending on which of the four stages it presents. The primary stage of syphilis classically presents with a painless ulcer (chancre). We report a case of the extragenital chancre on the nipple which is examined from skin biopsy and immunohistochemistry. This case showed that it is important to identify the special site’s pruritus erythema by pathology and serological examination.
Fuel cell is one of the future alternative energy sources. Commercial fuel cell membrane currently used is Nafion which has several disadvantages including low stability at high temperature, and low conductivity at low humidity. Therefore, it is necessary to study an alternative membrane for PEMFC. The purpose of this research is to synthesis an alternative fuel cell membrane from sulfonated PVDF doped with nanocomposites of natural zeolite of Cipatujah, West Java, Indonesia and TiO2 nanoparticles. The synthesis of zeolite-TiO2 nanocomposites was performed by sol-gel method using TEOT and zeolite of Cipatujah. The nanocomposites were added to PVDF in DMSO solvent prior to ultrasonification for 1, 2 and 3 hours. The membrane was casted and sulfonated with concentrated sulfuric acid for 4, 6 and 8 hours. The membrane was characterized with FTIR, SEM-EDX, and four-point probe spectroscope. The FTIR analysis shows the existence of sulfone in the polymer. The SEM-EDX results show that the SiO2 from the zeolite and TiO2 have been successfully inserted to the membrane. The conductivity analysis shows that the best membrane conductivity, 0.00389 S/cm was achieved for 6 hours sulfonation and 3 hours ultrasonication.
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