Temperonic Crystal: a superlattice for temperature waves in graphene

The temperonic crystal, a periodic structure with a unit cell made of two slabs sustaining temperature wave-like oscillations on short time-scales, is introduced. The complex-valued dispersion relation for the temperature scalar field is investigated for the case of a localised temperature pulse. The dispersion discloses frequency gaps, tunable upon varying the slabs thermal properties. Results are shown for the paradigmatic case of a graphene-based temperonic crystal. The temperonic crystal extends the concept of superlattices to the realm of temperature waves, allowing for coherent control of ultrafast temperature pulses in the hydrodynamic regime at above liquid nitrogen temperatures.Comment: 5 pages, 3 figure

Evapotranspiration models for a maize agro-ecosystem in irrigated and rainfed conditions

A high level of accuracy in the estimation of crop evapotranspiration (ET) may lead to significant savings of economic and water resources in irrigated agriculture. Although ET is a fundamental process in many applications, it cannot be directly measured but it has to be estimated by monitoring the exchange of energy/water above the vegetated surface (micrometeorological methods), or as a residual term of the hydrological balance (lysimeters, soil water budget). The techniques to be adopted are often complex, costly and require specific equipment. Thus, since the ‘50s, many researchers have devoted their activity to the development of models for its estimation. The available approaches can be classified in “direct” methods, based on the original Penman-Monteith (PM) equation, in which the canopy resistance rc is modelled, and “indirect” methods, based on the preliminary calculation of ET for a well-watered reference grass (ET0) with a constant rc, which is then multiplied by a crop coefficient Kc and, in case, by a stress coefficient Ks to obtain ET. Even if the latter approaches are more widely adopted for their practical simplicity, many authors show that the former often provide better ET estimates in absence of calibration of crop parameters. In this study the performances of different direct and indirect methods were evaluated in the case of a surface irrigated and of a rainfed maize grown in the Padana Plain (Northern Italy). The following models were considered: the “one-layer” original PM equation with three different models for rc (Monteith, Jarvis, Katerji-Perrier), the “two-layers” PM model proposed by Shuttleworth and Wallace, the “single” and “double” crop coefficient models illustrated in the Paper FAO-56. Latent heat fluxes measured in 2006 and 2011 in an experimental maize field by eddy-covariance were used to evaluate the models accuracy. Crop, soil and meteo data monitored contextually were used for the implementation of the different models. Results confirm that direct methods are more performing for both irrigated (2006) and rainfed (2011) conditions, with the SW model providing the best results and the FAO-56 models with generalized crop coefficients overestimating ET, especially during the middle growth stage

Climate change awareness, perceived impacts, and adaptation from farmers’ experience and behavior: a triple-loop review

Individuals and communities socially construct risk, and societies with greater risk perception may be more apt to mobilize or adapt to emergent threats like climate change. Increasing climate change awareness is often considered necessary in the first stages of the adaptation process to manage its impacts and reduce overall vulnerability. Since agriculture is affected by climate change in several ways, farmers can provide first-hand observations of climate change impacts and adaptation options. This paper aims to identify the current research trends and set the future research agenda on climate change awareness, perceived impacts, and adaptive capacity from farmers’ experiences and behavior. We analyzed a portfolio of 435 articles collected from WoS and Scopus databases between 2010 and 2020 using bibliometrics. From the original portfolio, we select 108 articles for a more comprehensive and systematic review. Publication trends and content analysis have been employed to identify influential work, delineate the mental structure of farmers’ beliefs and concerns, and identify main research gaps. The comprehensive analysis reported (1) farmers’ socio-demographic characteristics influencing farmers’ perceptions; (2) awareness and changing climate evidence due to human activity; (3) the main perceived effects (rising temperatures, changing rainfall patterns, and extreme events); (4) the most relevant adaptation measures (crop changing and soil/water conservation techniques); and (5) factors and barriers limiting adaptation (lack of information, credit, and expertness). The review outlines the main gaps and their drivers to help future researchers, managers, and decision-makers to prioritize their actions according to farmers’ concerns and their adaptive capacity to reduce farming vulnerability

Fifty years of the Journal of Agricultural Engineering

 Not availabl

Predicted and measured soil retention curve parameters in Lombardy region north of Italy

Water retention characteristics are fundamental input parameters in any modeling study on water flow and solute transport. These properties are difficult to measure and for that reason, we usually need to use direct and indirect methods to determine them. An extensive comparison between measured and estimated results is needed to determine their applicability for a range of different soils. However this study attempts to make a contribution specifically in this connection. These properties were determined in two representative sites located in Landriano field, in Lombardy region, northern Italy. In the laboratory we used the pressure plate apparatus and the tensiometric box. Field soil water retention was determined including measurements of soil water content with SENTEK probes and matric potential with tensiometers. The soil waer retention curves (SWRC) were also settled on with some recently developed pedo-transfert functions (PTFs). Field retention curves were compared against those obtained from PTFs estimations and laboratory measurements. The comparison showed that laboratory measurements were the most accurate. They had the highest ranking for the validation indices (RMSE ranging between 2.4% and 7.7% and bias between 0.1% and 6.4%). The second best technique was the PTF Rosetta (Schaap et al. 2001). They perform only slightly poorer than the laboratory measurements (RMSE ranging between 2.7% and 10% and bias between 0.3% and 7.7%). The lowest prediction accuracy is observed for the Rawls and Brakensiek (1985) PTF (RMSE ranging between 6.3% and 17% and bias between 5% and 10%) which is in contradiction with previous finding (Calzolari et al., 2001), showing that this function is well representing the retention characteristics of the area. Due to time and cost investments of laboratory and field measurements, we conclude that the Rosetta PTF developed by Schaap et al. (2001) appears to be the best to predict the soil moisture retention curve from easily available soil properties in the Lombardy area and further field investigations would be useful to support this finding

Towards a smart automated surface irrigation management in rice-growing areas in Italy

Italy is the leading rice producer in Europe, accounting for more than half of the total high-quality production of this crop. Rice is traditionally grown in fields that remain flooded starting with crop establishment until close to harvest, and this traditional irrigation technique (i.e., continuous submergence) is recognised as an important water resource sink (almost 40% of the irrigation water available worldwide is used for paddy areas). Meanwhile, the water management in rice areas requires a high level of labour because it is based on maintaining a predetermined water height in paddy fields and because the regulation of input and output flow is typically operated manually by the farmer. This study reveals the hardware and software characteristics of an automated and remote controlled technology tested for the first time in a rice farm near Pavia (Italy), during the 2016 growing season, aiming at a more efficient and less burdensome irrigation management system for rice fields. A water level sensor in the field provides the data required to govern the inflow regulation gate in real-time, according to the precise time to cut off the flow rate. Using a dedicated web page, the farmer can control flows, volumes and water levels in the fields by operating directly on the gate if necessary or setting the irrigation program according to his agronomic practices

O ENSINO DE HISTÓRIA NA CONTEMPORANEIDADE: METODOLOGIAS E LINGUAGENS EM SALA DE AULA

O presente estudo tem por objetivo analisar as possibilidades metodológicas e linguagens didáticas que facilitam o ensino de história (docência) em sala de aula para estudantes do ensino fundamental e ensino médio. É Fruto da minha experiência com o Estágio Curricular Complementar em História que tem por objetivo levar o acadêmico do curso de licenciatura em História ter contato com o espaço escolar e propor mudanças que vão ser fundamentais teoricamente na academia e aplicá-las ao retornar na escola para a docência. Na dialética entre academia e prática escolar é possível notar que a partir da Nova História as mudanças nas concepções de pesquisar história e consequentemente a ampliação das fontes de pesquisa possibilitam um novo olhar sobre o presente, passado e futuro e que os materiais didáticos foram também ganhando novas abordagens com novas metodologias e diferentes linguagens. Na sala de aula o processo é lento, mas também ocorreram modificações e com o passar do tempo o ensino de História, quase sempre aprendida por meio da memorização dos fatos, geralmente políticos, escolhidos e transcritos por historiadores com concepções diversas, foram abrindo espaço para incorporação de materiais didáticos críticos e reflexivos. Agora cabe ao professor visualizar novas possibilidades de utilização de tais materiais, pois, muitas vezes com o apoio do próprio livro didático pode-se conduzir o processo de ensino e aprendizagem, analisando e problematizando imagens, documentos, mapas, filmes e músicas.  É destes instrumentos, fontes e linguagens e sua utilização em sala de aula em que buscamos abordar e aplicar a experiência docente do Estágio Curricular.