The Static and Dynamic Sensitivity of Magnetostrictive Bioinspired Whisker Sensor

Magnetostrictive bioinspired whisker is a new kind of sensor that can realize tactile and flow sensing by utilizing magnetoelastic effect. The sensitivity is a key technical indicator of whisker sensor. The paper presented a new magnetostrictive whisker based on Galfenol cantilever beam, as well as its operation principle. Then, the static and dynamic sensitivity of the whisker sensor was investigated by using a self-made experimental system. The results illustrated that the proposed sensor has a high sensitivity. Its static sensitivity is 2.2 mV/mN. However, its dynamic sensitivity depends on the vibration frequency. When working at the natural frequency of the cantilever beam, the dynamic sensitivity performs an obvious increase—1.3 mV/mN at 3.5 Hz (the first-order natural frequency) and 2.1 mV/mN at 40 Hz (the second-order natural frequency), respectively

Diurnal fluctuation of volatile compounds emitted from four seasons rose (Rosa damascena Mill.) cultivated in Beijing

Four Seasons Rose is an old variety of Rosa damascena Mill. Using the technique of dynamic headspace collection, the volatiles emitted from the flowers of Four Seasons Rose were collected at five time points of a day. Then, by the means of thermal-desorption cold trap/ gas chromatography/mass spectrometer technique (TCT-GC/MS), constituent compounds of the volatiles were identified. After that, the daily dynamic variation of the floral scents from Four Seasons Rose was analyzed. The results demonstrated that the daily fluctuation of volatile components changed in different weather conditions. A total of 93 volatile compounds were identified. There are the most diversity of compounds at 14:00 in a fine day, and the compounds are as many as 78, whereas only 50 of volatile compounds are detected in a rainy day

Relationship between leaf physiologic traits and canopy color indices during the leaf expansion period in an oak forest

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 6, no. 12 (2015): 1-9, doi:10.1890/ES14-00452.1.Plant phenology has a significant impact on the forest ecosystem carbon balance. Detecting plant phenology by capturing the time-series canopy images through digital camera has become popular in recent years. However, the relationship between color indices derived from camera images and plant physiological characters are elusive during the growing season in temperate ecosystems. We collected continuous images of forest canopy, leaf size, leaf area index (LAI) and leaf chlorophyll measured by a soil plant analysis development (SPAD) analyzer in a northern subtropical oak forest in China. Our results show that (1) the spring peak of color indices, Gcc (Green Chromatic Coordinates) and ExG (Excess Green), was 18 days earlier than the 90% maximum SPAD value; (2) the 90% maximum SPAD value coincided with the change point of Gcc and ExG immediately after their spring peak; and (3) the spring curves of Gcc and ExG before their peaks were highly synchronous with the expansion of leaf size and the development of LAI value. We suggest it needs to be adjusted if camera-derived Gcc or ExG is used as a proxy of chlorophyll or gross primary productivity, and images observation should be complemented with field phenological and physiological information to interpret the physiological meaning of leaf seasonality.This research was funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions in the Discipline of Environmental Science and Engineering at Nanjing Forest University, Changjiang River Delta Urban Forest Ecosystem Research of CFERN (to H. Hu) and Brown University Seed Funds for International Research Projects on the Environment (to J. Tang)

Performance Analysis of Magnetostrictive Cantilever Beam with Modeling

A magnetostrictive cantilever beam model is established by combining an energy-based constitutive magnetostrictive model with the classical Euler-Bernoulli beam theory constitutive relations that describe the material behavior are based on energy minimization techniques. We use the saturation magnetization, the magnetostrictive constant and the 4th and 6th order anisotropy constants to calculate the Zeeman, stress-induced anisotropy and magnetocrystalline anisotropy energies per unit volume. The stress of the magnetostrictive cantilever beam is solved by classical beam theory. Experiments and simulations are conducted to study performance of the cantilever. The results demonstrated the sensing is primarily due to the dominating effect of compression over tension. A critical bias magnetic field is required below which the magnetostrictive sensing cannot be observed under bending

Mechanical-magneto coupled model of polymer-bonded magnetostrictive composites

In order to accurately predict the magneto-elastic property of polymer-bonded magnetostrictive materials, a new mechanical-magneto coupled nonlinear model is proposed in this paper. In the proposed model, the total strain of the composites is expressed by the matrix strain, magnetostriction eyestrains and strain concentration factors. Firstly, the interaction between the matrix and inclusion phase of the magnetostrictive composites is analyzed and the strain concentration factors are calculated with the Mori-Tanaka mean field method. Then, the magnetization process of the composites is analyzed in detail according to the demagnetizing field theory. Finally, the proposed model of magnetostrictive composites is obtained. Furthermore, in order to verify the proposed model, the performance of the magnetostrictive composites is tested, and the theoretical calculations are also compared with the experimental data. The results show that the given model can greatly simulate the stress concentration and precisely predict the magnetostrictive coefficient, saturation magnetostrictive coefficient as well as the magnetization of the composites

Pengaruh sense of school belonging terhadap student's misbehavior

Penelitian ini bertujuan untuk mengetahu pengaruh sense of school belonging terhadap student’s misbehavior. Penelitian ini merupakan penelitian korelasional dengan menggunakan teknnik pengumpulan data berupa skala likert yaitu skala sense of school belonging dan skala student’s misbehavior masing masing terdiri dari 30 aitem yang sudah melalui uji coba. Skala sense of school belonging memiliki reabilitas sebesar 0,899 sedangkan skala student’s misbehavior memiliki reabilitas sebesar 0,924. Subjek penelitian berjumlah 144 siswa dari jumlah populasi sebesar 576 siswa. Pengambilan data menggunakan simple random sampling. Hasil penelitian menujukkan bahwa terdapat pengaruh sense of school belonging terhadap student’s misbehavior dengan nilai signifikansi 0,000 < 0,05. Dalam table model summary pada analisis regresi linier sederhana, sense of school belonging memberikan pengaruh sebesar 17,7% terhadap student’s misbehavior. Pada table correlation, terdapat nilai koerfisien korelasi sebesar -0,420 yang berarti semakin tinggi sense of school belonging maka semakin rendah student’s misbehavior yang dilakukan oleh siswa

Classification of Urban Agricultural Functional Regions and Their Carbon Effects at the County Level in the Pearl River Delta, China

Exploring the transformation process of urban agricultural functions and its interaction with carbon effects based on regional differences is of great positive significance for achieving a low-carbon sustainable development of agriculture in metropolitan areas. By using the index system method, self-organizing feature maps (SOFM) network modeling, and Granger causality analysis, we divided the agricultural regional types of the Pearl River Delta (PRD) based on the spatio-temporal changes in urban agricultural functions and carbon effects at the county level in the PRD from 2002 to 2020, and analyzed the carbon effects generated by the agricultural functions according to the differences between the three agricultural regional types. The results show the following: (1) The changes in the basic functions of agriculture, the intermediate functions of agriculture, and the advanced functions of agriculture were different from the perspectives of both time and space. (2) The carbon effects produced by the areas with weak agricultural functions, the areas with medium agricultural functions, and the areas with strong agricultural functions were different. (3) The evolution of agricultural production types aggravated the grain risk in the PRD, and urban agriculture has potential in improving food security. (4) Based on the regional types of agricultural functions and considering the constraints of land and water, strategic suggestions such as integrating natural resources, improving utilization efficiency, upgrading technical facilities, and avoiding production pollution are put forward. (5) The green and low-carbon transformation of urban agriculture has its boundaries. The positive effects of the factors, namely the innovation of agricultural production methods, the change in agricultural organization modes, the impact of market orientation, and the transfer of the agricultural labor force, is limited. The findings of this paper provide valuable and meaningful insights for academia, policy makers, producers, and ultimately for the local population in general, driving the development of urban agriculture in a low-carbon and sustainable direction

Synthesis of Silver Nanoparticles Loaded onto Polymer-Inorganic Composite Materials and Their Regulated Catalytic Activity

We present a novel approach for the preparation of polymer-TiO2 composite microgels. These microgels were prepared by the in situ hydrolysis and condensation of titanium tetrabutoxide (TBOT) in a mixed ethanol/acetonitrile solvent system, using poly(styrene-co-N-isopropylacrylamide)/poly(N-isopropylacrylamide-co-methacrylic acid) (P(St-NIPAM/P(NIPAM-co-MAA)) as the core component. Silver nanoparticles (AgNPs) were controllably loaded onto the polymer-TiO2 composite microgels through the reduction of an ammoniacal silver solution in ethanol catalyzed by NaOH. The results showed that the P(St-NIPAM)/P(NIPAM-co-MAA)-TiO2 (polymer-TiO2) organic-inorganic composite microgels were less thermally sensitive than the polymer gels themselves, owing to rigid O&ndash;Ti&ndash;O chains introduced into the three-dimensional framework of the polymer microgels. The sizes of the AgNPs and their loading amount were controlled by adjusting the initial concentration of [Ag(NH3)2]+. The surface plasmon resonance (SPR) band of the P(St-NIPAM)/P(NIPAM-co-MAA)-TiO2/Ag (polymer-TiO2/Ag) composite microgels can be tuned by changing the temperature of the environment. The catalytic activities of the polymer-TiO2/Ag composite microgels were investigated in the NaBH4 reduction of 4-nitrophenol. It was demonstrated that the organic-inorganic network chains of the polymer microgels not only favor the mass transfer of the reactant but can also modulate the catalytic activities of the AgNPs by tuning the temperature