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Numerous studies on sampling methods have been conducted to balance the inspection efficiency and accuracy of coordinate measuring machines (CMMs). However, almost all existing methods only take into account the information from the processed surface during the reconstruction process. To address this limitation, an adaptive sampling method based on co-kriging method is proposed, according to the characteristics of the interpolation reconstruction method, we treat certain feature points on the surface as anchor points and determine the distribution of other measurement points through iteration. In the reconstruction process, we employ the co-kriging interpolation method and combine extra information of the model surface to enhance the reconstruction accuracy. Through simulations and actual measurements of processed surfaces, we compare the proposed method with other algorithms. The results indicate that our method is particularly suited for complex surfaces with a limited number of measurement points, and can substantially reduce the reconstruction error when the number of measurement points is the same. • A method using CAD model information has been proposed, which improves reconstruction accuracy without additional time cost. • An adaptive sampling method based on co-kriging interpolation has been proposed. • This method has a high degree of scalability, compensating of CAD information is effective for any adaptive method. • The proposed method can significantly improve inspection accuracy, especially when there are limited measurement points. [ABSTRACT FROM AUTHOR]

Different from the finite/fixed-time control methodologies on longitudinal/attitude synchronization or 2-D motion of UAVs, this article attempts to propose a distributed adaptive specified-time control scheme for synchronization tracking of networked 6-degree-of-freedom (DOF) UAVs. To be specific, the novel specified-time performance functions (STPFs) are designed in such a way that the desired performance bounds can be imposed on velocity and attitude tracking errors. Based on the transformed errors, by utilizing the barrier Lyapunov functions (BLFs), a distributed specified-time control scheme is constructed with adaptive robustifying terms to enhance the fault-tolerant ability and compensate the modeling uncertainties. By means of Lyapunov stability theory, it is proved that the resulting control scheme can guarantee the boundedness of all closed-loop state variables, and preserve the guaranteed performance bounds for synchronization tracking errors of velocity and attitude at the same time. Theoretical results are confirmed by experiment and simulation validations. • A specified-time prescribed performance control scheme for 6-DOF UAVs is proposed. • Novel specified-time performance functions on velocity and attitude are designed. • The actuator faults and complicated disturbances are compensated by adaptive terms. [ABSTRACT FROM AUTHOR]

Eucalyptus bark (EB) is a promising biomass to replace fossil fuels, but its ash content is high and the energy density is particularly low. In this paper, it was proposed to upgrade EB to prepare solid biofuel by mild hydrothermal treatment (HTT) and pelletization. It was found that HTT could effectively remove troubling elements like Na, K, Zn, Mn, S, Cl, and P in EB. The remaining ashes tend to form higher melting point compounds, whose softening temperature (ST) and flow temperature (FT) increased from 1326 °C to 1399 °C and from 1348 °C to 1425 °C, respectively. The higher heating value of EB increased from 16.32 to 17.68 MJ/kg after HTT. The density, volume expansion, compressive strength, and durability of the bio-pellet fuel after HTT were all superior to raw EB. HTT and pelletization is a promising method to prepare solid biofuel from EB. [Display omitted] • Hydrothermal treatment can improve the combustion performance of eucalypt bark. • The influence of hydrothermal treatment on ash slagging behavior was evaluated. • Ash of eucalypt bark derived hydrochar have higher melting point. • Thermo-equilibrium modeling can effectively predict the ash slagging behavior. • Hydrochar pellet have better physical properties than eucalypt bark pellet. [ABSTRACT FROM AUTHOR]

[Display omitted] • Feed system thermal error model based on positioning error decoupling is proposed. • Thermally induced error is affected by motion and non-motion heating. • Feed system already has thermal errors when it is not working. • Thermal error model based on MLR has physical meaning and good robustness. • MLR has better accuracy than data-driven models over long time prediction. Thermal error modeling and compensation considering of the measured positioning error decoupling for the lathe with a slant bed is proposed. Due to the complex coupling factors of thermal error, the current compensation methods exhibit limited applicability and generalization. The linear fitting method is used to decouple geometric error and thermal error from the positioning error. The motion heating and non-motion heating experiments of X-direction feed system were carried out to investigate the principle of thermal error generation and the impact factors. The multiple linear regression model of the thermal error was established based on the analysis of the thermal error measurement results. To verify the effectiveness of the proposed model, the thermal error at two working conditions was predicted, and then the error compensation was carried out. The results show that the positioning error is reduced by more than 84% and 92% with the present method compared with that without compensation. This research provides effective method for the generation principle and compensation of thermally induced errors of lathe with a slant bed. [ABSTRACT FROM AUTHOR]

Expansins are nonenzymatic cell wall proteins that play significant role in plant development as well as stress responses. Hereby, an expansin-like gene, GhEXLB2 was isolated from a cotton (Gossypium hirsutum L.) protoplast with suppression subtractive hybridization to characterize and study its responses against abiotic stresses. GhEXLB2 is the cell-wall localized protein. The expression of GhEXLB2 level was significantly high under polyethylene glycol and salt treatments. GhEXLB2 was further characterized in vitro by cloning and transformation into cotton. Cotton plants overexpressing GhEXLB2 showed enhanced drought tolerance at germination, seedling and flowering stages. After polyethylene glycol (PEG) treatment at germination stage, the length of main root and hypocotyl of overexpressing lines was significantly longer than YZ1 (wild type) and RNAi lines. In addition, H 2 O 2 and malondialdehyde (MDA) contents were lower, while superoxide dismutase (SOD) and peroxidase (POD) activity was detected higher in overexpressing seedlings. On the other hand, higher SOD and POD activity was detected in overexpressing lines than WT plants in soil. In addition, water use efficiency (WUE), soluble sugar, and chlorophyll contents were also significantly greater in overexpressing plants. The present study revealed that GhEXLB2 play crucial role in enhancing drought resistivity in cotton. • Developing drought tolerant varieties could be a way to mitigate the effects of drought stress. • Transgenic cotton plants overexpressing and RNAi GhEXLB2 were developed to characterize GhEXLB2 in drought stress. • The overexpressing lines showed higher drought tolerance compared to mock and RNAi lines. • Hydrogen peroxide and malondialdehyde contents were low in overexpressing lines. [ABSTRACT FROM AUTHOR]

In this work, the electrocaloric (EC) effect was studied in the (100- x)BaHf 0.2 Ti 0.8 O 3 - x Ba 0.94 Sm 0.04 TiO 3 (BHT- x BST) ceramics fabricated by the conventional solid-reaction method. By tuning composition to their diffuse phase transition (DPT), invariant critical point (ICP) and first-order phase transition (FPT), the large electrocaloric response with a temperature change of ΔT = 0.46 °C (at 64 °C) under 30 kV/cm and an electrocaloric strength of ΔT/ΔE = 0.18 K mm/kV under 12 kV/cm were achieved in BHT-70BST. In addition, BHT-50BST shows a broad EC working temperature window from 28 °C to 68 °C because of its diffusion behavior near the ferroelectric-to-paraelectric phase transition and multiphase coexistence. The maximum ΔT of BHT-50BST is larger than that of BHT-40BST with only diffusion character but no multiphase coexistence. This work may provide a design strategy to enhance EC performance with a broad working temperature region in lead-free rare-earth doped BaTiO 3 -based ceramics by combining the diffusion behavior, multiphase coexistence and heterovalent substitution. [ABSTRACT FROM AUTHOR]

Organ-level vascularization has been a long-standing challenge in the field of tissue engineering. Recent advances, particularly in the use of projection stereolithography and food colors as photoabsorbers are highlighted, as are several recent studies on the clinical translation of engineered vasculature. [ABSTRACT FROM AUTHOR]

Ensemble trick has been widely used in extreme learning machine (ELM), and most paradigms concern about the training phase with expectation of improving their generalization ability. Unlike traditional strategies, this paper pays more attention to the prediction phase and proposes a discriminatory approach called ensemble based reactivated regularization ELM (ER 2 -ELM). In short, the novel literature consists of two interrelated steps where the probability density estimation is first conducted to show the degree of difficulty of identifying an instance, and then a random factor is adopted to determine whether the ELM base learner is sequentially reactivated. As such, instances easily to identify cost less computing burden, while the vague ones are taken carefully consideration. Compared with other ensemble methods, the prediction computation overhead decreases. In the end, a number of examples, including UCI benchmark datasets, handwritten digits, object detection, etc., are employed so as to illustrate its state-of-the-art performance. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is widely distributed in nature, especially in a variety of food commodities. It is confirmed to be the most toxic of all the aflatoxins. The toxicity of AFB1 has been well investigated, and it may result in severe health problems including carcinogenesis, mutagenesis, growth retardation, and immune suppression. Epigenetic modifications including DNA methylation, histone modifications and regulation of non-coding RNA play an important role in AFB1-induced disease and carcinogenesis. To better understand the evidence for AFB1-induced epigenetic alterations and the potential mechanisms of the toxicity of AFB1, we conducted a review of published studies of AFB1-induced epigenetic alterations. [ABSTRACT FROM AUTHOR]

As a common renewable energy source of the ocean, wave energy has the advantages of high energy density and wide distribution, but it is also characterized by time variability and ultra-low frequency, which makes it a challenging task to obtain. Here, by combining the quasi-zero adjustable stiffness (QZS) mechanism with magnetoelectric (ME) composites, we propose a QZS magnetoelectric generator (QZS-MEG) to effectively adapt to wave energy in different low-frequency (< 2 Hz) environments. To improve the energy response and conversion efficiency at ultra-low frequencies, an inverted pendulum and abrupt magnetic change architecture are designed in the QZS mechanism and ME generator, respectively. Moreover, the adjustable clamp, flexible hinge and swing block are further introduced to accommodate the variable frequency and multi-directional wave energy. Finally, the practicability of QZS-MEG is verified through experiments. When the driving frequency ranges from 0.5 to 1.6 Hz, QZS-MEG reaches a maximum output power of 1.37 mW at 0.33 MΩ and shows broadband non-resonance characteristics. This work may provide an effective strategy for the large-scale acquisition of ultra-low frequency blue energy. [Display omitted] • A is proposed to achieve ultra-low frequency, variable frequencies and multi-directional wave energy harvesting. • The abrupt magnetic structure and arrayed ME transducer are designed to improve the energy conversion efficiency. • When the frequency within 2 Hz, the maximum output power reaches 1.37 mW and shows broadband non-resonant characteristics. [ABSTRACT FROM AUTHOR]

A repeater is able to amplify attenuating weak signals, as a consequence, transmission distance was greatly elongated. Plus, CTCSS avoid interference among repeaters to some extent, thus providing more channels to accommodate increasing number of users. The problem is, how to coordinate the repeaters in a certain area, flat or mountainous, to suit the users’ demands about communication. Queuing Theory was introduced to solve the problem, the optimum answer is not a constant but is given based on the probability of waiting before served. In our model, the statistic parameter “Arrival Rate” is given by steps, thus forming a series of trails. Different isolines of user performances (especially probability of waiting) are selected and fit the curve to get approximate solutions. If 1000 users are in the flat area, mean number of users who are expected to communicate is 400, the number of repeaters required goes to 42, when waiting probability is set 10 –5 . If 10000 users, of which 4000 user couples are expected to communicate, the number of repeaters required goes to 224, under the waiting provability of 10 –5 . In the model, the results are plotted on a 3-dimensional coordinate system, a visual view of parameter flexibility was given. [ABSTRACT FROM AUTHOR]

• The rock layer between the two coal seams is affected by repeated mining and is prone to rotation instability. • Based on the "block-dispersions" theory, the structure and failure process of the roof of the roadway under the gob is analyzed. • The floor stress distribution law after mining in the upper coal seam is calculated according to the elastic theory. With the increase in energy demand and in mining intensity, the phenomenon of multiple coal seam mining has appeared in major coal mining countries. While the downward mining method is generally adopted and under the damage of the upper coal seam, the structure and stress environment of the coal roof are very different from those of a single coal seam in remining. The rock layer between the two coal seams is affected by repeated mining and is prone to rotation instability, which makes it more difficult to reserve gob-side entries along the gob in the lower coal seams. This article mainly targets the case of the gob in the Panel #11426 of Xieqiao Mine, and studies the failure mechanism and control technology of the gob-side entry retaining in short-distance coal seam. First, the floor stress distribution law after mining in the upper coal seam is calculated according to the elastic theory, and verified by FLAC3D numerical simulation; secondly, the floor failure depth after the upper coal seam is calculated according to the elastic–plastic theory. Based on the "block-dispersions" structure, the failure process of the roof of the roadway under close gob is analyzed. Further, it is proposed during the roadway excavation, to adopt support methods such as erecting U-steel retractable supports and back-wall filling; during the mining and before the gob-side entry retaining, the installation of roof bolts (cables), the reinforcement of the roof of the area to be filled and the in-wall filling techniques etc. to control the surrounding rock of gob-side entry. The engineering test was carried out along the track at the Panel #11426 of Xieqiao Mine. The onsite monitoring showed that: the maximum subsidence of the reserved gob-side entry roof along the gob was 180 mm, and the maximum approaching distance of the two banks was 328 mm, which met the engineering requirements. The research results can provide guidance for the design gob-side entry retaining along gobs under similar mining geological conditions. [ABSTRACT FROM AUTHOR]

Bioprinting offers unprecedented control in the 3D deposition of cells and biomaterials, but reproducing tissue microarchitecture and cell diversity remains challenging. Brassard et al. now overcome these limitations by bioprinting organoid-forming stem cells at high densities. This study opens new possibilities for controlling tissue structural complexities across multiple length scales. [ABSTRACT FROM AUTHOR]