Synthesis of hybrid organic-inorganic perovskite platelets by vacuum impregnation

In perovskite solar cells and optoelectronics, perovskite film morphology controls the performance of the device. Various methods have been developed to control the morphology and coverage of the perovskite films. In this article platelet type perovskite morphlogy was synthesized using low temperature vacuum impregnation of the perovskite solution CH3NH3PbI3 resulting in complete coverage on TiO2 film. Vacuum impregnation synthesis of perovskites has the advantage of low cost and low temperature which faciliates application in flexible electronics and solar cells

The correlation of the anodic and cathodic open circuit potential (OCP) and power generation in microbial fuel cells (MFCs)

The overall open circuit potential (OCP) and short circuit potential of anodes and cathodes and the power generation in air-cathode membraneless single chamber microbial fuel cells (SCMFCs) were investigated in this study. Two SCMFCs with different anode areas (10 and 40 cm2) were tested in 8 weeks of experiments. At the beginning of the tests, the anodes were well colonized and the cathodes were in a clean condition. Anodic OCPs remained stable throughout the experiments while the cathodic OCPs decreased dramatically in the first week. The overall OCP of SCMFCs followed the cathodic OCP trend. The power generation of SCMFCs dropped dramatically in the first 3 weeks and then remained stable. The short circuit potential indicated that the performance of SCMFCs was mostly limited by the cathodic process of oxygen diffusion to the platinum.</jats:p

Effects of anode and cathode area on organic compounds removal and power generation in membraneless microbial fuel cell (MFC)

This study focused on the effects of anode and cathode area on power generation and wastewater treatment in membraneless air-cathode single chamber microbial fuel cells (SCMFCs). The results showed that the power generation of the SCMFCs did not vary with anode area, while the power generation slightly increased with cathode area. Specifically, the power generation increased 10-16% (from 230-236 μW to 265-276 μW) when the cathode area increased from 1.25 to 10 cm2. The COD degradation efficiency increased slightly (10-15%) with anode area, and substantially (more than 50%) with cathode area. The increase in cathode area led to a higher power generation and higher wastewater treatment efficiency in MFCs.</jats:p

Effects of cathodic platinum loadings and organic substrate concentrations on the performance of single chamber microbial fuel cells treating wastewater

Single electrode kinetics was investigated in a membrane-less single chamber air cathode microbial fuel cell (SCMFC) fed with raw wastewater. Anode kinetics was studied to better understand mass transport diffusion limitations without the addition of readily degradable organic substrates. Cathode electrode kinetics was investigated with varying platinum (Pt) loading. Even though higher Pt loading resulted in better cathode performance, a reduction of Pt loadings by two orders of magnitude did not significantly lower performance. The cathode performance decreased substantially over time especially for low currents due to the depletion of oxygen on the cathode surface. This study showed that the anode kinetics rather than cathode kinetics limited the overall performance of SCMFCs at low organics concentrations.</jats:p

Anatomia foliar de soja infectada por Phakopsora pachyrhizi H. Sydow & Sydow e tratadas com extratos vegetais Leaf anatomy of soybean infected with Phakopsora pachyrhizi H. Sydow & Sydow and treated with plant extracts

Folhas de Glycine max (L.) Merril,infectadas pelo fungo Phakopsora pachyrhizi H. Sydow & Sydow e tratadas com extratos vegetais foram avaliadas, visando determinar in vivo as modificações anatômicas nas diferentes estruturas/tecidos foliares, além de reconhecer prováveis mecanismos de defesa. Folhas de soja cultivar 181 provenientes do quinto nó foram inoculadas com fungo e tratadas com diferentes extratos vegetais, água e álcool 70%. Para comparação foram analisadas a anatomia das folhas sadia e infectada e realizadas medidas nas estruturas/tecidos foliares. Na folha infectada, observou-se destruição da epiderme e parênquima lacunoso, visível proliferação de tricomas e cutícula espessada, principalmente na face abaxial. Observou-se a presença de compostos fenólicos nas células da epiderme quando rompida, em função do crescimento micelial. Nas folhas infectadas e tratadas com os extratos vegetais de Azadirachta indica, Maytenus ilicifolia e Allium sativum, as estruturas/tecidos vegetais apresentaram aumento de espessura por alongamento celular.<br>Glycine max (L.) Merril leaves, infected by the fungus Phakopsora pachyrhizi H. Sydow & Sydow and treated with plant extracts, were evaluated with the aim of determining in vivo the anatomical modifications in different leaf structures and of identifying probable defense mechanisms. Leaves from the 181 soybean cultivar originated from the fifth node were inoculated with the fungus and treated with different plant extracts, water and alcohol at 70%. For comparison, the anatomy of the healthy and infected leaves was analyzed and the leaf structures were measured. In the infected leaf, there was destruction of the epidermis and lacunar parenchyma, apparent trichome proliferation and denser cuticle, especially on the abaxial surface. There were also phenolic compounds in ruptured epidermis cells, due to mycelium growth. In the infected leaves treated with Azadirachta indica, Maytenus ilicifolia and Allium sativum extracts, the plant tissues had an increase in thickness due to cell elongation

Essential oils for rust control on coffee plants Óleos essenciais no controle da ferrugem em cafeeiro

Rust is considered the most important disease in coffee because it causes severe defoliation in plants and, consequently, reduction in productivity. This study evaluated the in vitro effect of essential oils of cinnamon, citronella, lemongrass, clove, tea tree, thyme, neem and eucalyptus on the germination of urediniospores of Hemileia vastatrix; the effectiveness of these oils to control rust on seedlings of coffee cultivars Catucaí 2SL, Catuaí IAC 62 and Mundo Novo 379/19 in the greenhouse; and the effect of more promising oils on urediniospores of H. vastatrix by transmission electron microscopy (TEM). All the essential oils inhibited the germination of urediniospores with increasing concentrations. All oils promoted partial control of the disease in the greenhouse. However, the oils of thyme, clove and citronella, at a concentration of 1000 µL L-1, were most effective in controlling the disease on cultivars Catucaí 2SL, Catuaí IAC 62 and Mundo Novo 379/19, respectively. The images generated in TEM showed that urediniospores exposed to oils of clove, citronella and thyme promoted cellular disorganization and cytoplasmic vacuolization, which was more pronounced in urediniospores exposed to citronella oil. The oils of thyme, clove and citronella are promising for the control of rust in coffee.<br>A ferrugem é considerada a doença de maior importância no cafeeiro, pois causa acentuada desfolha nas plantas e, consequentemente, redução na produtividade. Este trabalho avaliou o efeito in vitro de óleos essenciais de canela, citronela, capim-limão, cravo-da-índia, árvore-de-chá, tomilho, nim e eucalipto na germinação de urediniósporos de Hemileia vastatrix; a eficácia desses óleos no controle da ferrugem em mudas de cafeeiro das cultivares Catucaí 2SL, Catuaí IAC 62 e Mundo Novo 379/19 em casa de vegetação; e o efeito dos óleos mais promissores sobre urediniósporos de H. vastatrix por meio de microscopia eletrônica de transmissão (MET). Todos os óleos essenciais inibiram a germinação dos urediniósporos com o aumento das concentrações. Todos os óleos promoveram controle parcial da doença em casa de vegetação. No entanto, os óleos de tomilho, cravo-da-índia e citronela, na dose de 1000 µL L-1, foram os mais eficazes no controle da doença nas cultivares Catucaí 2SL, Catuaí IAC 62 e Mundo Novo 379/19, respectivamente. Nas imagens geradas em MET, observou-se que urediniósporos expostos aos óleos de cravo-da-índia, citronela e tomilho apresentaram desorganização citoplasmática e vacuolização celular, sendo esta mais pronunciada em urediniósporos expostos ao óleo de citronela. Os óleos de tomilho, cravo-da-índia e citronela são promissores no controle da ferrugem em cafeeiro