Analysis, realization and experiment of Lamb wave phased arrays for damage detection and imaging in carbon composite structures

Phased array theory is utilized in the unmanned aerial vehicle (UAV) wing box to identify the damage in the structure. The phased array theory has been adapted to Lamb wave propagation to improve the detection ability of local defects in the complex composite structure. The validity of the proposed method is demonstrated by experimental research in which input signals exerted at piezoelectric (PZT) actuators/sensors on the UAV wing box are successfully reconstructed by using the phased array method. The recognition result is shown on a mapped image. The original mapped image uses gray level transformation method to enhance the image identifiable degrees. And the time of arrival of the Lamb wave signal is calculated by Shannon Wavelet. The experiments is done on carbon composite structure using one dimensional PZT linear sensors array exemplifies that phased array theory well utilized in scanning and detecting the damage and the screw loosening in the structure. The original image is processed by the gray level transformation to improve the contrast and the recognition

Experimental Report on the Effectiveness of the Insecticide Chloromethiuron 3

No. 3 diflubenzuron is one type of benzoyl N-Phenylurea compound, a type of insect chitin synthesis inhibitor, and has a unique disinsection mechanism. It can depress the chitinous formation on the insect epidermis, and make it die in the process of ecdysis or metamorphism. It has particularly effective impact on lepidopterous larvae, and it can control many kinds of pests?such as armyworm, cabbage worm, cotton bollworm?Clanis bilineata, Pine caterpillar, Hyphantria cunea? mosquito screwworm etc. No. 3 diflubenzuron hardly has effect on imagoes, and has low virulence on higher animals; the medium lethal dose of white rats is 15,000 mg/kg on w/w basis. It has high virulence on target insects, but low virulence on non-target insects. This chemical has no specific smell, does not pollute the environment, and is safe for humans and animals. Thus, it is a new diflubenzuron with high-effect and low-virulence, and could replace some organochlorine insecticides such as DDT, Hexachlorocyclohexane and others. Mythimna separata Walker is one of the main pests of crops in Jilin Province. The infested area per year is usually 5 – 10 million mu [666.7m2 ] in the whole province; and it will reach above 10 million mu in years of mass-outbreak. It leads to severe reduction of yield or even no yield if the M. separata are not controlled in time. In order to replace the organo-chlorine pesticides with their highly toxic residue?we have been doing experimental investigations and research on the chitin synthesis inhibitors - No. 1 diflubenzuron and No. 2 diflubenzuron - since 1977. In addition, we have done systemic research on No. 3 diflubenzuron supported by leaders in the Science Committee of our province since 1979. Our results are from indoor control experiments of No. 3 diflubenzuron colloidal suspension M. separata, which was synthesized and provided by the Tonghua Chemical Engineering Institute, and field-plot experiments and demonstration extension experiments within Jilin province. In this paper, the partial results of our research are summarized as follows.Originating text in Chinese.Citation: Liang, Shulian, Sun, Yajie, Chen, Ruilu. (1985). Experimental Report on the Effectiveness of the Insecticide Chloromethiuron 3. Journal of Jilin Agricultural Sciences, 35(2), 36-44

MARKET EFFICIENCY AND HOUSE PRICE DYNAMICS IN RESIDENTIAL REAL ESTATE MARKETS OF CHINA

Master'sMASTER OF SOCIAL SCIENCE

High Spectral Spatial Resolution Synthetic HyperSpectral Dataset form multi-source fusion

This research paper introduces a synthetic hyperspectral dataset that combines high spectral and spatial resolution imaging to achieve a comprehensive, accurate, and detailed representation of observed scenes or objects. Obtaining such desirable qualities is challenging when relying on a single camera. The proposed dataset addresses this limitation by leveraging three modalities: RGB, push-broom visible hyperspectral camera, and snapshot infrared hyperspectral camera, each offering distinct spatial and spectral resolutions. Different camera systems exhibit varying photometric properties, resulting in a trade-off between spatial and spectral resolution. RGB cameras typically offer high spatial resolution but limited spectral resolution, while hyperspectral cameras possess high spectral resolution at the expense of spatial resolution. Moreover, hyperspectral cameras themselves employ different capturing techniques and spectral ranges, further complicating the acquisition of comprehensive data. By integrating the photometric properties of these modalities, a single synthetic hyperspectral image can be generated, facilitating the exploration of broader spectral-spatial relationships for improved analysis, monitoring, and decision-making across various fields. This paper emphasizes the importance of multi-modal fusion in producing a high-quality synthetic hyperspectral dataset with consistent spectral intervals between bands.Comment: IJCNN workshop on Multimodal Synthetic Data for Deep Neural Networks (MSynD), 202

Product Quality and Consumer Search

An increase in quality shifts up the distribution of match utilities offered by firms and makes consumers pickier. The number of products that consumers inspect does not necessarily increase in quality. Higher search costs may lead to less quality investment, and the equilibrium price may decrease. If the equilibrium is inefficient, it is because of the inadequacy of quality investment. The market level of quality investment is excessive (insufficient) and consumers are too (little) picky from the point of view of welfare maximization if and only if a rise in quality results in consumers inspecting a higher (lower) number of products.</p

Damage and Control of Soybean Aphid

The soybean aphid, Aphis glycines, is one of the major insect pests of seedling soybean. This aphid has become a serious problem in soybean production due to heavy infestation in recent years and lack of favorable varieties resistant to soybean aphids. To understand the damage by soybean aphids and evaluation of control effect, in 1989-1990, we investigated the population dynamics of soybean aphid in the fields and its effect on soybean growth, development and yield.Originating text in Chinese.Citation: Wang, Suyun, Sun, Yajie, Chen, Ruilu, Zhai, Baoping, Bao, Xiangzhi. (1994). Damage and Control of Soybean Aphid. Technology and Promotion of Plant Protection, 2, 5-6

Design and Experiment of PZT Network-based Structural Health Monitoring Scanning System

AbstractThe active Lamb wave and piezoelectric transducer (PZT)-based structural health monitoring (SHM) technology is a kind of efficient approach to estimate the health state of aircraft structure. In practical applications, PZT networks are needed to monitor large scale structures. Scanning many of the different PZT actuator-sensor channels within these PZT networks to achieve on-line SHM task is important. Based on a peripheral component interconnect extensions for instrumentation (PXI) platform, an active Lamb wave and PZT network-based integrated multi-channel scanning system (PXI-ISS) is developed for the purpose of practical applications of SHM, which is compact and portable, and can scan large numbers of actuator-sensor channels and perform damage assessing automatically. A PXI-based 4 channels gain-programmable charge amplifier, an external scanning module with 276 actuator-sensor channels and integrated SHM software are proposed and discussed in detail. The experimental research on a carbon fiber composite wing box of an unmanned aerial vehicle (UAV) for verifying the functions of the PXI-ISS is mainly discussed, including the design of PZTs layer, the method of excitation frequency selection, functional test of damage imaging, stability test of the PXI-ISS, and the loading effect on signals. The experimental results have verified the stability and damage functions of this system

Critical accumulation of fertilizer-derived uranium in Icelandic grassland Andosol

Long-term phosphorus (P) fertilizer application can lead to an accumulation of uranium (U) in agricultural soil, potentially posing risks on the environment and human health. In this study, we found that such risks could be severe in two long-term grasslands (Andosol) in Iceland (Sámstaðir and Geitasandur) after about 50 years of P fertilization. At Sámstaðir, where P fertilizers were applied at an annual rate of 39.3 kg ha−1 year−1, the soil U concentration increased from 0.65 mg kg−1 in the unfertilized soil to 6.9 mg kg−1 in the fertilized surface soil (0–5 cm). At Geitasandur with P fertilization rate at 78.6 kg ha−1 year−1, the soil U concentration reached 15 mg kg−1. The average annual U accumulation rates were 130 and 310 µg kg−1 year−1, respectively. These values were larger, by up to a factor of ten, than any previously reported rates of fertilizer-derived U accumulation. However, the U concentration in one of the applied P fertilizers was 95 mg U kg−1 fertilizer, similar to the median value of those reported in previous studies, and thus unlikely to be the only factor leading to the high U accumulation rates. By contrast, as our Andosols had low bulk density within a range of 0.2 to 0.5 g cm−3, the annual U inputs to the 0–5 cm soil were 19 g ha−1 year−1 and 32 g ha−1 year−1 at the two sites, respectively, within the range of to-date reported values in agricultural systems. In addition, we found that U was mostly retained in the surface soil rather than mobilizing to deeper soil. This was likely due to the fact that the Andosols were rich in organic matter which promoted U retention. Therefore, the observed high U accumulation rates were a result of the combination of (i) the large amounts of the applied P fertilizers and (ii) the soil properties of the Andosols with low bulk density and elevated organic matter content concentrating U in the upper surface soil. Our study shows that agricultural production systems on Andosols may have already suffered from severe U contamination due to P fertilization. We are therefore calling for future checks and regulations on P fertilizer-related soil U accumulation in these and certain comparable agroecosystems