Outlier removal method for the refinement of optical measured displacement field based on critical factor least squares and subdomain division

As a representative type of outlier, the abnormal data in displacement measurement often inevitably occurred in full-field optical metrology and significantly affected the further evaluation, especially when calculating the strain field by differencing the displacement. In this study, an outlier removal method is proposed which can recognize and remove the abnormal data in optically measured displacement field. A iterative critical factor least squares algorithm (CFLS) is developed which distinguishes the distance between the data points and the least square plane to identify the outliers. A successive boundary point algorithm is proposed to divide the measurement domain to improve the applicability and effectiveness of the CFLS algorithm. The feasibility and precision of the proposed method are discussed in detail through simulations and experiments. Results show that the outliers are reliably recognized and the precision of the strain estimation is highly improved by using these methods.

Development of Inorganic Impregnated Phase Change Material(PCM) in the Pores of Activated Carbon

Objectives : Recently, energy-related research has shifted from developing alternative energy to the efficient management technology of the produced energy. As an alternative, research on phase change materials (PCMs) capable of absorbing and releasing heat as an energy medium has been conducted. This study developed a more efficient heat storage medium using activated carbon as a medium for the phase change material. At the same time, we developed a method for efficiently impregnating the phase change material into the activated carbon pores.Methods : The activated carbon used in this experiment was charcoal powder activated carbon (250-350 mesh) and granular activated carbon. The inorganic phase change materials used in the experiment was manganese nitrate hexahydrate. The method for impregnating the phase change material was pressurization method and dilution method. The heat absorption / emission capacity of the developed material was examined within the range of 10℃ to 50℃.Results and Discussion : The Scanning electron microscope (SEM) and Transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDX) analysis showed that the phase change material was filled in the pore of activated carbon. When the phase change material is filled by the pressurized method, the material properties of manganese nitrate hexahydrate are reflected, resulting in absorption and release of heat at each phase change temperature. As a result of experiments for the selection of the optimum solvent in the phase change material filling study using the dilution method, when ethanol was used as the solvent, the heat absorption was clearly observed even after the phase change material was loaded. As a result of selecting the optimal dilution ratio, the ratio of ethanol was determined to be 1:1 as the dilution ratio with the lowest amount of floating activated carbon. The optimal solvent removal method experimental results show that the heat absorption/release section occurred when the ethanol was removed by evaporation at 85℃ temperature.Conclusions : 1) Both the pressurization method and the dilution method are filling methods in which inorganic phase change materials can be immobilized inside activated carbon, and heat absorption and release characteristics are maintained even after loading. 2) The heat absorption release was maintained for ethanol and the optimal dilution ratio was 1:1. 3) In case of the dilute solvent removal method, the heat absorption/release capacity was maintained when the solvent was removed using only the vaporization method.

Is the destruction or removal of atmospheric methane a worthwhile option?

Removing methane from the air is possible, but do the costs outweigh the benefits? This note explores the question of whether removing methane from the atmosphere is justifiable. Destruction of methane by oxidation to CO 2 eliminates 97% of the warming impact on a 100-yr time scale. Methane can be oxidized by a variety of methods including thermal or ultraviolet photocatalysis and various processes of physical, chemical or biological oxidizers. Each removal method has energy costs (with the risk of causing embedded CO 2 emission that cancel the global warming gain), but in specific circumstances, including settings where air with high methane is habitually present, removal may be competitive with direct efforts to cut fugitive methane leaks. In all cases however, great care must be taken to ensure that the destruction has a net positive impact on the total global warming, and that the resources required would not be better used for stopping the methane from being emitted. This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.

Retrieval of Chlorophyll a Concentration in Water Considering High-Concentration Samples and Spectral Absorption Characteristics

The envelope removal method has the advantage of suppressing the background spectrum and expanding the weak absorption characteristic information. However, for second-class water bodies with a relatively complex water quality, there are few studies on the inversion of chlorophyll a (Chl-a) concentration in water bodies that consider the spectral absorption characteristics. In addition, the current research on the inversion of the Chl-a concentration was carried out under the condition of sample concentration equilibrium. For areas with a highly variable Chl-a concentration, it is still challenging to establish a highly applicable and accurate Chl-a concentration inversion model. Taking Dongting Lake in China as an example, this study used high-concentration samples and spectral absorption characteristics to invert the Chl-a concentration. The decap method was used to preprocess the high-concentration samples with large deviations, and the envelope removal method was used to extract the spectral absorption characteristic parameters of the water body. On the basis of the correlation analysis between the water Chl-a concentration and the spectral absorption characteristics, the water Chl-a concentration was inverted. The results showed the following: (1) The bands that were significantly related to the Chl-a concentration and had a large correlation coefficient were mainly located in the three absorption valleys (400–580, 580–650, and 650–710 nm) of the envelope removal curve. Moreover, the correlation between the Chl-a concentration and the absorption characteristic parameters at 650–710 nm was better than that at 400–580 nm and 580–650 nm. (2) Compared with the conventional inversion model, the uncapped inversion model had a higher RP2 and a lower RMSEP, and was closer to the predicted value of the 1:1 line. Moreover, the performance of the uncapped inversion model was better than that of the conventional inversion model, indicating that the uncapped method is an effective preprocessing method for high-concentration samples with large deviations. (3) The predictive capabilities of the ER_New model were significantly better than those of the R_New model. This shows that the envelope removal method can significantly amplify the absorption characteristics of the original spectrum, which can significantly improve the performance of the prediction model. (4) From the inversion models for the absorption characteristic parameters, the prediction models of A650–710 nm_New and D650–710 nm_New exhibited the best performance. The three combined models (A650–710 nm&D650–710 nm_New, A650–710 nm&NI_New, A650–710 nm&DI_New) also demonstrated good predictive capabilities. This demonstrates the feasibility of using the spectral absorption feature to retrieve the chlorophyll concentration.

Assessment and Appliction of Whole-Herd-Sampling, qPCR-Based-Testing, and Precision-Removal Method in Eliminating ASFv in Four Large Swine Herds in China

Since the first report of ASFV in China in 2018, conventional whole herd depopulation method to control ASF has proved unwieldly because of high production intensity and complex trade network. To provide an alternative to conventional methods, we evaluated the feasibility of implementating an extensive sampling method and qPCR tests to determine the status of ASFV in herds, with a rapid response to identified outbreaks. By assessing and applying these methods without whole herd depopulation, we successfully controlled ASF and eliminated the virus from 4 large swine herds. The time to negative herd was 19, 28, 14, and 1 days in farms 1-4 respectively. Retention rates of pigs of farm 1 to farm 4 was 69.7%, 65%, 99.4% and 99.72% respectively. We anticipated that this innovative method would replace the conventional stamping out one and greatly facilitate the control and eradication of ASFV in China and worldwide.