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Abstract Near-infrared spectroscopy (NIRS) is a fast and powerful analytical tool in the food industry. As an advanced chemometrics tool, multi-way analysis shows great potential for solving a wide range of food problems and analyzing complex spectroscopic data. This paper describes the representative multi-way models which were used for analyzing NIRS data, as well as the advances, advantages and limitations of different multi-way models. The applications of multi-way analysis in NIRS for the food industry in terms of food process control, quality evaluation and fraud, identification and classification, prediction and quantification, and image analysis are also reviewed. It is evident from this report that multi-way analysis is presently an attractive tool for modeling complex NIRS data in the food industry while its full potential is far from reached. The combination of multi-way analysis with NIRS will be a promising practice for turning food data information into operational knowledge, conducting reliable food analyses and improving our understanding about food systems and food processes. To the best of our knowledge, this is the first paper that systematically reports the advances on models and applications of multi-way analysis in NIRS for the food industry.
Abstract Nitrogen (N) transformation in soil directly determines the effectiveness of N for plant growth. Biochar has received evermore attention because of its significant ability to improve soil. However, the effects of biochar on N-related microorganisms (Lycopersicon esculentum Mill.) in tomato cultivation soil, N transformation, utilisation of water and N fertiliser, and tomato yield remain unclear. The objective of this study was to investigate the responses of N-related microorganisms to biochar and N fertilisation in soil, along with the implications of biochar for altering N transformation, N uptake by tomatoes, and utilisation of water and N fertiliser. A two-year greenhouse experiment containing six biochar levels under drip irrigation (0, 10, 30, 50, 70, and 90 t ha−1) and two N fertiliser application rates (190 and 250 kg ha−1) was conducted in the northwest of China. The results showed that adding biochar significantly promoted urease activity, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and the number of amoA-type nitrifiers in the soil. The MBC:N ratio and the number of nirS-type denitrifiers were significantly inhibited when the added amount of biochar was greater than or equal to 30 t ha−1. Moreover, biochar can increase the water content in the soil and can reduce the N lost to leaching. The inorganic N (NO3− and NH4+) in the soil could be better maintained in the rootzone and better absorbed by tomato plants when adding 30, 50, and 70 t ha−1 of biochar. The amount of N fertiliser could be reduced by 24% without a significant loss of tomato yield when the amount of biochar added was over 30 t ha−1. It was indicated that the yield of tomatoes and the net profits were quadratically related to the application rate of biochar. In the test area, 53 t ha−1 of biochar with 190 kg ha−1 of N and 44.6 t ha−1 of biochar with 190 kg ha−1 of N were calculated to be the best amounts from the perspectives of tomato yield and net profit, respectively. Thus, biochar promotes N transformation by regulating N-related microorganisms; hence, it increases the inorganic N in the roots of the plants, reduces N lost to leaching, and significantly promotes the N absorption of tomatoes. The results in this research are of great significance for the development of management strategies for tomato maintenance, environmental protection, and resource conservation.
Abstract Tomato is an important economic crop that is widely consumed worldwide. Tomato production is mainly limited by the use of nitrogen fertilizer, sunlight, soil and water conditions. Biochar is one of the soil amendments, and it is recognized as a promising practice for improving crop production in agriculture. The effect of biochar on the photosynthetic traits and tomato yield under reduced nitrogen fertilizer application is still not well understood. The objective of this research is to investigate the influence of biochar application on the photosynthesis and yield of tomato under reduced nitrogen fertilizer application from the perspectives of the nutrient uptake of plants (nitrogen and phosphorus), leaf photosynthetic pigment and leaf gas exchange parameters. Two-year greenhouse experiments containing six biochar levels (0, 10, 30, 50, 70, and 90 t ha−1) and two nitrogen fertilizer application rates (190 and 250 kg ha−1) were conducted. Compared with C0, C50 significantly improved the nitrogen uptake (74–80%) and phosphorus uptake (76–95%) by tomato plants and further enhanced the photosynthetic traits of tomato leaves (net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr) and chlorophyll (2–60%), which lead to the highest gains in tomato yield (more than 50%) even when the applied nitrogen fertilizer was significantly reduced (from 250 kg ha−1 to 190 kg ha−1). The photosynthesis rate had a linear correlation with the total nitrogen and phosphorus accumulation and tomato yield. The results will enhance our understandings about the effect of biochar on the photosynthesis and yield of tomato and be of importance for practical agricultural management.
Abstract Most objects show high degrees of spatial regularity (e.g. beach umbrellas appear above, not under, beach chairs). The spatial regularities of real-world objects benefit visual working memory (VWM), but the mechanisms behind this spatial regularity effect remain unclear. The “encoding specificity” hypothesis suggests that spatial regularity will enhance the visual encoding process but will not facilitate the integration of information online during VWM maintenance. The “perception-alike” hypothesis suggests that spatial regularity will function in both visual encoding and online integration during VWM maintenance. We investigated whether VWM integrates sequentially presented real-world objects by focusing on the existence of the spatial regularity effect. Throughout five experiments, we manipulated the presentation (simultaneous vs. sequential) and regularity (with vs. without regularity) of memory arrays among pairs of real-world objects. The spatial regularity of memory objects presented simultaneously, but not sequentially, improved VWM performance. We also examined whether memory load, verbal suppression and masking, and memory array duration hindered the spatial regularity effect in sequential presentation. We found a stable absence of the spatial regularity effect, suggesting that the participants were unable to integrate real-world objects based on spatial regularities online. Our results support the encoding specificity hypothesis, wherein the spatial regularity of real-world objects can enhance the efficiency of VWM encoding, but VWM cannot exploit spatial regularity to help organize sampled sequential information into meaningful integrations.
Abstract The tomato is an important economic crop that is a main ingredient of some prepared food as well as a focus of the agricultural industry. Optimizing nitrogen (N) fertilizers is essential for sustainable agricultural development, while the excessive use of N fertilizers leads to environmental and food production problems. As a soil amendment, biochar has been widely used to improve soil quality and crop yield. However, little information is available on the effects of biochar and N fertilizer reduction on tomato plant, soil characteristics in tomato cultivation and tomato production. In this study, a greenhouse experiment was carried out in Yangling, Shaanxi province, China, including four biochar levels (0, 30, 50, and 70 t ha−1) under drip irrigation and four N application rates (170, 190, 210, and 250 kg ha−1). The results showed that adding too much biochar (e.g., 70 t ha−1) and reducing N fertilizer too far (e.g., by 32%) will not lead to satisfactory results in terms of tomato growth, tomato yield and quality, and economic benefits. Biochar addition could significantly enhance microbial abundance, enzyme activity, and tomato growth compared with non‒biochar treatments when reducing the amount of applied N fertilizer by 16% or 24% (N2 and N3). From the perspectives of tomato yield, tomato quality (sugar‒acid ratio and vitamin C (VC) content), and economic benefits, optimal application rate of biochar and N fertilizer based on the silty clay loam soil of northwest China under drip irrigation is proposed, respectively. The proposal is based on both multidimensional nonlinear regression models and a comparison with experimental treatments. For example, biochar addition at 50 t ha−1 and reducing N fertilizer by 24% achieved the greatest tomato yield. Compared with non-biochar treatment under the corresponding N fertilizer level, soil enzyme activity (urease, phosphatase, and catalase), microbial abundance (bacteria, fungi, and actinomycetes), leaf gas exchange parameters (gs, Pn, and Tr), and biomass increased on average by 88.76%, 7.49%, 43.23%, and 39.67%, respectively. Based on a comprehensive consideration of tomato yield, VC content, sugar‒acid ratio, and economic benefits, 35 t ha−1 biochar and 200 kg ha−1 N fertilizer is the recommended combination of biochar and nitrogen fertilizer for local farmers.
Abstract The titania slag was utilized to prepare synthetic rutile using microwave roasting at a temperature of 1100 °C for 2 h. The compositions of the titania slag and the changes in the chemical states of the sample resulting from microwave roasting were studied by XRD, SEM, Raman, and XPS, respectively. The XRD results indicate that the product’s prominent peaks correspond to the standard card of rutile TiO2 have significantly increased after microwave heating. The Raman vibration peaks at 164.2 cm−1, 203.9 cm−1, and 636.2 cm−1 of the raw materials were caused by Ti3O5, Ti2O3, and anatase TiO2, respectively. After microwave roasting, all the Raman vibration peaks were related to the rutile TiO2 phase. The XPS analysis showed that the surface of the sample mainly contained Ti, C, and O elements, and after microwave roasting, the content of Ti4+ increased significantly. The results indicated that microwave roasting is an effective method to produce rutile TiO2. The roasted product meets the requirements of high-grade synthetic rutile.
Abstract Rutile titanium dioxide is widely used in coatings, cosmetics, paper products, and other industries as the source of white inorganic pigment. The common preparation methods of rutile from titanium slag include the molten salt method, hydrochloric acid method, oxidation–reduction method, etc. In this paper, the NaOH-KOH sub-molten salt method was used to activate titanium slag. After a series of subsequent leaching processes and an attached roasting process with the assistance of microwave technology, a nanocluster was formed by nanorods with a diameter below 100 nm and a length below 500 nm. It is found that titanate changes to the stable metantitanate at a temperature of 80 °C in the process of acid leaching. Moreover, the relationship between the concentration of sub-molten salt, calcination temperature, and titanium leaching rate was analysed by kinetics. The results show that the leaching rate of titanium reached the peak when the mixed alkali concentration was 15 mol/L, and the leaching rate of titanium reached the maximum value when the roasting temperature was 450 °C. According to the Arrhenius equation, the activation energy of titanium slag in the NaOH-KOH sub-molten salt system was 130.8 kJ/mol. The pre-exponential factor was 5.44 × 10−4 m2/s, and a chemical reaction process controlled the whole process.
Abstract Most of the manganese resources in China have existed in the form of low-grade pyrolusite which is not utilized efficiently because of the high energy consumption and environmental pollution during the reduction process. Applying microwave heating to minerals reduction endows improved production efficiency and reduced production costs. In the present work, rapid preparation of manganese monoxide (MnO) was attempted through reducing low-grade pyrolusite with coal reducing agent by microwave heating, with the samples characterized by XRD, scanning electron microscopy, XPS as well as TG/DSC. The influences of the reduction reaction parameters on the reduction process of Mn in pyrolusite were comprehensively studied. The results indicated that higher temperatures and longer holding times facilitated the reduction roasting of pyrolusite, and manganese monoxide can be fabricated with a reduction ratio of 97.7% obtained at 650°C for 50 min. The mechanism of the gradual transformation of MnO2 to MnO from the macroscopic to the molecular level was also revealed in the order of MnO2 → Mn2O3 → Mn3O4 → MnO. Compared to traditional roasting, the proposed microwave-enhanced roasting process benefits from the superior kinetic conditions provided by the synergy between microwave enhancement and compact pellets, and thus reduced the roasting temperature and roasting time.
The rate and temporal pattern of neural spiking each have the potential to influence computation. In the cerebellum, it has been hypothesized that the irregularity of interspike intervals in Purkinje cells affects their ability to transmit information to downstream neurons. Accordingly, during oculomotor behavior in mice and rhesus monkeys, mean irregularity of Purkinje cell spiking varied with mean eye velocity. However, moment-to-moment variations revealed a tight correlation between eye velocity and spike rate, with no additional information conveyed by spike irregularity. Moreover, when spike rate and irregularity were independently controlled using optogenetic stimulation, the eye movements elicited were well-described by a linear population rate code with 3–5 ms temporal precision. Biophysical and random-walk models identified biologically realistic parameter ranges that determine whether spike irregularity influences responses downstream. The results demonstrate cerebellar control of movements through a remarkably rapid rate code, with no evidence for an additional contribution of spike irregularity.