FANO resonances in solid-fluid one and two dimensional systems

The gaol of this paper is to demonstrate that the propagation of acoustic waves in a single slab made of a homogeneous one dimensional (1D) solid embedded in a fluid at oblique incidence on a slab made of two dimensional (2D) rectangular rods immersed in a fluid, can exhibit transmission zeros near resonances the so-called Fano resonances

Oil palm land conversion in Pará, Brazil, from 2006-2014: evaluating the 2010 Brazilian Sustainable Palm Oil Production Program.

Global models of biophysical suitability for oil palm consistently rank Brazil as having the greatest potential for expansion, with estimates as high as 238 Mha of suitable lands. In 2010, Brazil launched the Sustainable Palm Oil Production Program (SPOPP) to incentivize oil palm development without deforestation on as much as 30Mha. Here we examine oil palm expansion before and after the SPOPP?s launch. In Par´a, the major oil palm producing state in Brazil, we analyze the extent and change in oil palm cultivation from 2006&#8722;2014 using satellite imagery, ground-truthed verification, site-based interviews, and rural environmental (land) registration data. Between 2006&#8722;2014, oil palm area (&#8805;9 ha) expanded >200% to &#8764;219 000 ha. Of the &#8764;148 000 ha of oil palm developed, &#8764;91% converted pasturelands while &#8764;8% replaced natural vegetation, including intact and secondary forests. Although >80% of all oil palm parcels rest <0.5 km from intact forests, direct conversion of intact forests declined from &#8764;4% pre-SPOPP (2006&#8722;2010) to <1% post-SPOPP (2010&#8722;2014). Despite low and declining deforestation rates associated with oil palm expansion in Par´a, our results also show a low area of oil palm development overall compared with reported land suitability. To explore potential contributing factors, we conducted semi-structured interviews with researchers, company representatives, and government officials involved in the sector to characterize the perceived factors influencing oil palm development and the role of agro-ecological suitability mapping among them. Interviews indicated that: (1) individual effects of suitability mapping efforts to encourage oil palm expansion on cleared areas, i.e. without deforestation, cannot be disentangled from pre-existing public and private deforestation reduction initiatives; and, (2) socio-economic constraints, e.g. high relative production costs and limited familiarity with this crop, appear to partially explain the major discrepancy between estimated potential suitable areas with realized oil palm development

Порівняння впливу ZnO та TiO2 на характеристики перовскітних сонячних елементів за допомогою програмного пакету SCAPS-1D

У пошуках високоефективного та недорогого матеріалу для фотоелектричних пристроїв четвертого покоління органічно-неорганічні гібридні перовскітні сонячні елементи набувають популярності як новий поглинач. Зараз досліджуються два типи архітектури твердотільних перовскітних пристроїв. Це мезопористі і плоскі гетеропереходи. Обидві структури складаються з п'яти шарів: прозорого провідного оксиду, матеріалу для переносу електронів, активного шару перовскіту, матеріалу для переносу дірок, і зворотного контакту. У роботі за допомогою одновимірного симулятора ємності сонячних елементів (SCAPS-1D) моделюються ключові характеристики перовскітних сонячних елементів з оксидом цинку (ZnO) та діоксидом титану (TiO2) як матеріалом для переносу електронів. TiO2 є найбільш часто використовуваним матеріалом в перовскітних сонячних елементах, але для його осадження потрібна висока температура, яка обмежує промислову обробку пристроїв. ZnO широко використовується в напівпровідниковій промисловості і вважається альтернативою TiO2 завдяки відмінному переносу електронів. Дослідження за допомогою моделювання зосереджені на товщині, довжині дифузії носіїв та енергії забороненої зони шару поглинача, які впливають на фотоелектричні властивості пристроїв на сонячних елементах. Також досліджується вплив робочої температури. Згідно з результатами, використання ZnO як матеріалу для переносу електронів покращує ефективність сонячних елементів порівняно з TiO2. Завдяки нижній межі зони провідності, яка полегшує перенос фотогенерованих електронів у перовскітному сонячному елементі, найкраща ефективність, отримана від структури з використанням шару ZnO, становить 25,40 % при температурі навколишнього середовища. Результати моделювання показують, що товщина поглинача 500 нм підходить для досягнення високої ефективності пристроїв.In the quest for a highly efficient and low-cost material for fourth-generation photovoltaic devices, organic-inorganic hybrid perovskite solar cells are gaining popularity as a new absorber. Currently, two types of solid-state perovskite device architecture are being researched. These are mesoporous and planar heterojunctions. Both structures are made up of five layers: transparent conductive oxide, electron transport material, perovskite active layer, hole transporting material, and back contact. In this work, the key characteristics of perovskite solar cells with zinc oxide (ZnO) and titanium dioxide (TiO2) as electron transport material are simulated using the one-dimensional Solar Cell Capacitance Simulator (SCAPS1D). TiO2 is the most commonly used material in perovskite solar cells, but its deposition requires high temperature, which limits the commercial processing of flexible devices. ZnO is widely used in the semiconductor industry and is considered an alternative to TiO2 due to its excellent electron transport. Simulation studies focus on the thickness, carrier diffusion length, and band gap energy of the absorber layer, which affect the photovoltaic properties of solar cell devices. The effect of working temperature is also examined. According to the findings, the use of ZnO as an electron transport material improves the cell efficiency compared to TiO2. Because of the lower edge of the conduction band, which facilitates the transport of photogenerated electrons in a perovskite solar cell, the best efficiency got from a structure using ZnO layer is 25.40 % at ambient temperature. The simulation results show that an absorber thickness of 500 nm is appropriate for achieving high efficiency

Vertical Mulching e manejo da água em semeadura direta Vertical Mulching and water management in no tillage system

A intensa mobilização do solo no sistema cultivo convencional causou degradação da estrutura, compactação e adensamento do solo abaixo da camada arável, reduzindo a macroporosidade e a taxa de infiltração de água no solo, com conseqüente aumento de escoamento superficial, de erosão e de assoreamento de rios e de reservatórios. A semeadura direta, que protege a superfície do solo, praticamente controlou a perda por erosão hídrica, os terraços foram eliminados, pelos agricultores, e a conseqüência foi maior escoamento superficial do que no sistema cultivo convencional. Com o objetivo de avaliar o comportamento hidrológico do vertical mulching em semeadura direta, em relação ao escoamento superficial, realizou-se esta pesquisa nos anos agrícolas 2002/2003 e 2003/2004, em Latossolo Vermelho distrófico típico, na região fisiográfica do planalto médio do Rio Grande do Sul, isto é, um experimento em escala de campo, com parcelas sem vertical mulching, com vertical mulching a cada 10 m e com vertical mulching a cada 5 m, no delineamento de blocos ao acaso com três repetições. Sulcos em nível, perpendiculares ao declive, com dimensões de 0,08 m de largura por x 0,38 m de profundidade, foram abertos e preenchidos com palha compactada o suficiente para prevenir desmoronamento das paredes do sulco. No ciclo da cultura da soja e do trigo foram simuladas chuvas com duas intensidades, 70 e 106 mm h-1. Foram determinados o escoamento superficial, a taxa de infiltração básica de água no solo e a concentração de nutrientes e de CO no escoamento superficial. Os resultados indicam que o vertical mulching na semeadura direta reduz, significativamente, o volume do escoamento superficial aumenta a taxa de infiltração básica de água no solo e reduz também as perdas totais de nutrientes e de CO devido ao menor volume de água no escoamento superficial.<br>Intensive soil mobilization in the conventional tillage system has caused soil structure degradation, soil compaction below the arable layer, and decreased macroporosity. These changes resulted in reduced soil water infiltration rate and increased runoff, soil erosion and sedimentation in rivers and reservoirs. In the no tillage system the water erosion from the soil surface is practically controlled, and the terraces were eliminated by the farmers. Nevertheless, the surface flow is higher than it was in the conventional tillage system. With the objective of evaluating the hydrological behavior of vertical mulching in no tillage systems as related to runoff, this study was developed in the growing seasons of 2002/2003 and 2003/2004 on a Red Latosol (Oxisol) in the Planalto Médio region of Rio Grande do Sul State, Brazil. A field experiment was installed using plots without vertical mulching, with vertical mulching at every 10 m and with vertical mulching at every 5 m. It was used a randomized block design with three replications. Leveled furrows of vertical mulching, perpendicular to the soil slope (0.08 m wide by 0.38 m deep) were dug and filled with straw compacted enough to stabilize the furrow sides. Rainfall intensities of 70 and 106 mm h-1 were simulated on soybean and wheat to determine runoff, soil water infiltration rate, and nutrient and organic carbon concentration in the runoff. The results showed that vertical mulching in no tillage significantly reduces surface runoff and increases the water infiltration rate into the soil. It also reduces the total nutrient and organic carbon losses due to the reduction of water runoff