An Agricultural Spraying Robot Based on the Machine Vision

Accurate target spraying is a key technology in modern and intelligent agriculture. For solving the problems of pesticide waste and poisoning in the spraying process, a spraying robot based on binocular machine vision was proposed in this paper. A digital signal processor was used to identify and locate tomatoes as well as to control the nozzle spray. A stereoscopic vision model was established, and color normalization, 2G-R-B, was adopted to implement background segmentation between plants and soil. As for the tomatoes and plants, depth information and circularity depended on the nozzle’s target, and the plant shape area determined the amount of pesticide. Experiments shown that the recognition rate of this spraying robot was up to 92.5% for tomatoes

Experimental and numerical analysis on impacts of significant factors on carbon dioxide absorption efficiency in the carbon solidification process

Onboard carbon capture and storage is an excellent solution to reduce the greenhouse gas emissions from shipping. This paper focuses on the absorption process and CO2 gas flow rate, the geometry of absorption tank and the concentration of absorption solution are key factors affecting the absorption efficiency. This paper will illustrate the experimental results of the impacts of these factors on the CO2 absorption efficiency. Meanwhile, results from CFD simulations of effects of the key factors on CO2 absorption rates will be presented in this paper. Pressure distributions, solution concentration and velocity of CO2 gas and solution are derived from the simulations. The results of the simulations provide fundamentals and insight understanding of the design of a proto-type demonstration system onboard a case ship. In addition to the key factors, the effect of atmosphere temperature was simulated and analyzed. Comparisons between the experiment and simulation have been conducted and the results have shown a good agreement. Optimized values of the factors are obtained from the comparisons and analyses. The numerical simulations of temperature effects on CO2 absorption rate and optimized temperature for the absorption process are also presented in the paper

CarDD: A New Dataset for Vision-based Car Damage Detection

Automatic car damage detection has attracted significant attention in the car insurance business. However, due to the lack of high-quality and publicly available datasets, we can hardly learn a feasible model for car damage detection. To this end, we contribute with the Car Damage Detection (CarDD), the first public large-scale dataset designed for vision-based car damage detection and segmentation. Our CarDD contains 4,000 high-resolution car damage images with over 9,000 wellannotated instances of six damage categories (examples are shown in Fig. 1). We detail the image collection, selection, and annotation processes, and present a statistical dataset analysis. Furthermore, we conduct extensive experiments on CarDD with state-of-theart deep methods for different tasks and provide comprehensive analysis to highlight the specialty of car damage detection

The Simulation Analysis of Long-Span Membrane Structure

The analysis of wind load characteristics of gas-ribbed film structure plays an important role in the performance of the long-span membrane structure. This paper mainly researches on the long-span rib membrane structure. Surface wind pressure of the membrane structure is calculated by fluent, the distribution of force and surface pressure of the membrane structure under different angles and wind speeds is obtained. The worst working condition of the wind approach angle is 60°. Maximum force angle is positively correlated with windward angle and the length of structure.

Reviews on current carbon emission reduction technologies and projects and their feasibilities on ships

Concern about global climate change is growing, and many projects and researchers are committed to reducing greenhouse gases from all possible sources. International Maritime (IMO) has set a target of 20% CO2 reduction from shipping by 2020 and also presented a series of carbon emission reduction methods, which are known as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operation Indicator (EEOI). Reviews on carbon emission reduction from all industries indicate that, Carbon Capture and Storage (CCS) is an excellent solution to global warming. In this paper, a comprehensive literature review of EEDI and EEOI and CCS is conducted and involves reviewing current policies, introducing common technologies, and considering their feasibilities for marine activities, mainly shipping. Current projects are also presented in this paper, thereby illustrating that carbon emission reduction has been the subject of attention from all over the world. Two case ship studies indicate the economic feasibility of carbon emission reduction and provide a guide for CCS system application and practical installation on ships

Melatonin modulates the effects of diethylstilbestrol (DES) on the anterior pituitary of the female Wistar rat.

We studied the anti-tumorigenic effect of melatonin in diethylstilbestrol (DES)-treated anterior pituitaries in rats. Twenty-one female Wistar rats were randomly allocated into three groups: vehicle control rats, DES-treated rats, and DES-treated rats co-administrated with melatonin beginning at week 13. At the end of 16 weeks, rats were weighed and decapitated for morphological studies, including an H+E staining-based score evaluation in regard to cell proliferation, angiogenesis, immunostaining for VEGF, MMP-9, and AQP-1, and electron microscopy. Compared with vehicle, long-term treatment of DES significantly reduced rat body weight and increased H+E score, both of which were counteracted by melatonin. Administration of melatonin also reduced the expression of VEGF and MMP-9, although no changes were detected in AQP-1 expression. In rats cotreated with melatonin, the RER loosened and accumulated more secretion granules. We thus concluded that melatonin can modulate the effects of DES on the rat anterior pituitary by downregulating expression of VEGF and MMP-9 and suppressing the release of secretion granules, suggesting a therapeutic potential in estrogen-induced pituitary malfunctions

Performance evaluation of linear variable valve actuation for a linear engine generator

The Joule cycle Linear Engine Generator (LEG) is a promising power generation technology with the potential to achieve zero carbon emissions. However, the LEG expander valve actuation system presents unique challenges due to its lack of a traditional crankshaft, the need for swift valve lift and reversal, and variable lift. This paper presents a Linear Variable Valve Actuation (LVVA) system for a LEG prototype. The LVVA system is powered by voice coil motors. Rigorous experimental investigations were conducted to analyze crucial performance factors, including energy consumption, force balance, energy flow distribution, and the relationship between valve lift duration and energy consumption. The results show that the LVVA system can achieve the desired valve lift and timing, as well as very small variations in LEG performance compared to the model using an ideal lift curve. The LVVA accounts for approximately 3.59 % of the LEG power output. The energy consumption of 1.607 J per valve stroke provides a slight advantage over traditional actuation systems. The obtained optimal lift curves were used to refine the LEG model. The influence of valve lift curves on LEG performance was evaluated which reveals rapid valve openings and relatively short duration contributing to improved LEG performance

Combustion characteristics of oxymethylene dimethyl ether-diesel blends:An experimental investigation using a constant-volume combustion chamber

The combustion characteristics of oxymethylene dimethyl ether (OMEx) and its blends with diesel have been investigated using a multi-hole injector in a constant-volume combustion chamber. The results show OMEx addition can reduce the ignition delay, especially when blends of more than 50 vol% are used, at low chamber temperature. Two individual heat-release peaks are observed for OMEx during premixed combustion at 750 K, due to a pronounced low-temperature heat-release phase. The chamber temperature of 800 K can be regarded as a transition point for the behavior of burn duration as well as maximum ROHR peak, mostly caused by combustion regime transition from premixed- to diffusion combustion. It appears that there is an approximate linear relation between maximum ROHR peak and the time at which this peak occurs with injection pressure. The ignition delay of OMEx is almost insensitive to a decrease in ambient oxygen concentration. And the premixed ROHR profile, due to its high oxygen content, is very similar and only ignition delay and burn duration increase slightly. Additionally, comparisons of natural luminosity results for OMEx and diesel indicate that OMEx produces near-zero soot values. Luminosity is expected to be caused by chemiluminescence alone, which increases with injection pressure

Atomic Ramsey interferometry with S- and D-band in a triangular optical lattice

Ramsey interferometers have wide applications in science and engineering. Compared with the traditional interferometer based on internal states, the interferometer with external quantum states has advantages in some applications for quantum simulation and precision measurement. Here, we develop a Ramsey interferometry with Bloch states in S- and D-band of a triangular optical lattice for the first time. The key to realizing this interferometer in two-dimensionally coupled lattice is that we use the shortcut method to construct $\pi/2$ pulse. We observe clear Ramsey fringes and analyze the decoherence mechanism of fringes. Further, we design an echo $\pi$ pulse between S- and D-band, which significantly improves the coherence time. This Ramsey interferometer in the dimensionally coupled lattice has potential applications in the quantum simulations of topological physics, frustrated effects, and motional qubits manipulation