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Fan G.,Shandong Agricultural University | Fan G.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | Gao L.,Nanjing University of Aeronautics and Astronautics
International Journal of Advanced Manufacturing Technology | Year: 2014

Electric hot incremental forming is feasible and easy to control to form hard-to-form sheet metals, but the limited accuracy is a major deficiency. In order to find methods to improve precision, single-point electric hot incremental of Ti-6Al-4V titanium sheet was numerically simulated using MSC.Marc, and experimental investigations were also carried out in this paper. Through numerical analysis, distributing laws of temperature, thermal strain, stress, and equivalent strain were revealed, and impacts of cold contract and thermal strain on forming were also revealed. Analysis showed that electric hot incremental forming is a complex pyroplastic deformation, and there is a large internal stress in single-point electric hot incremental forming. The incremental sheet forming region can be divided into three parts: bending deformation at the beginning, shear forming at middle, and reverse bending at last; it is important to enhance the accuracy of the bending part and the reverse bending part, and adequate support must be provided in the beginning to reduce the bending part. In order to form a workpiece with small angle, two-point incremental forming was adopted at first because the gravity of clamp can reduce the reverse bending, then single-point electric hot incremental forming was adopted to enhance the accuracy and reduce internal stress of workpiece. © 2014 Springer-Verlag London. Source


Fan G.,Shandong Agricultural University | Fan G.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | Gao L.,Nanjing University of Aeronautics and Astronautics
International Journal of Advanced Manufacturing Technology | Year: 2014

Although Ti-6Al-4V titanium can be quickly and easily formed by electric hot incremental forming, the material property is the key factor for industrial application. In the current work, mechanical properties of Ti-6Al-4V sheet in one-sided electric hot incremental forming, such as microstructure, hardness, and tensile strength, were investigated. The results show that the current is obviously the most important factor to elevate temperature, so a higher feed rate can be adopted if the current is increased. In order to keep a constant processing temperature, an online temperature detector and current feedback system should be adopted. After observation and analysis of the microstructure of forming workpieces, the electric hot incremental forming is an integrated process, which involves plastic hardening and annealing. The temperature of the tool-workpiece contact side reached the β-transus one, α phase disappeared, and the basket weave structure was formed because of the fast air-cool. A composite organization with superior property which includes elongated α phase grains and basket weave structure can be acquired by one-sided electric hot incremental forming. If a uniform metal structure is obtained, special heat treatment must be adopted. Micro-hardness analysis shows that electric hot incremental forming is an enhanced processing. In order to improve the tensile strength, the oxidation of sheet must be prevented and inert gas protection should be adopted in future research. © 2014 Springer-Verlag London. Source


Hou Y.-T.,Shandong Agricultural University | Hou Y.-T.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | Ren J.,Shandong Agricultural University | Ren J.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | And 3 more authors.
Crop Protection | Year: 2012

The efficiency of slightly acidic electrolyzed water (SAEW with pH 5.0-6.5) and strong acidic electrolyzed water (StAEW with pH less than 3.0) on the inactivation of Phytophthora parasitica var. nicotianae growth in vitro was studied. The treatment conditions included inundating time (30, 60, 120 and 300 s), treatment interval (24, 48 and 72 h) and available chlorine concentration (ACC, 30, 60 and 90 mg/L) with either StAEW (pH 2.35) or SAEW (pH 6.06). The results showed that inundating time had no effect on the efficiency of SAEW for inactivation of pure P. parasitica var. nicotianae cultures (P > 0.05). The inhibition rate increased with increasing ACC and oxidation reduction potential (ORP) at the same pH and inundating time (P < 0.01) with electrolyzed water (EW). Although the pH of SAEW (pH 6.06) was much higher than that of StAEW (pH2.35), the inhibition rate of SAEW was similar to that of StAEW (P > 0.05) at ACCs of 60 and 90 mg/L. Moreover, the experiments confirmed that the optimal treatment interval was 48 h (P < 0.01). An inhibition rate of higher than 50% of P. parasitica var. nicotianae growth in vitro was achieved with SAEW (pH 6.06, ORP 922 mV and ACC of 90 mg/L) when inundating time was 30 s and treatment interval was 48 h. The findings of this study indicate that EW may be a promising disinfectant, which can achieve inactivation of P. parasitica var. nicotianae with added benefits of reduced health hazards and environmental pollution. © 2012 Elsevier Ltd. Source


Lu Z.,Shandong Agricultural University | Lu Z.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | Zhang L.,Shandong Agricultural University | Zhang G.,Shandong Agricultural University | Liu S.,Shandong Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

With the development of plastic film mulching cultivation technology, crop output increases substantially and crops are suitable for more areas. Consequently, a change of agricultural production mode and a leap of agricultural productivity occurred thereafter. However, with the application scope of the film expanding quickly, its side effects also emerges. Because of the " white pollution" caused by the remnant plastic film after potato etc. crops harvest, it is very important to solve the problem of low gathering film efficiency, leaking film, separating soil and film, wrapping film, unloading film of the existing plastic film collector. In order to counter the problems mentioned above, and combine with agronomic requirements of potato, a new project of chain guide rail-type plastic film collection is designed in this paper. Loosening soil shovels and picking-up film teeth which are next to each other in a chain, cooperate together to improve the rate of gathering film. The pallet of mulching film is in row structure, which will be able to leak soil, and further boost the efficiency to separate soil and film. While operating correctly, shovels loose soil and picking-up film teeth penetrate plastic film to pick them up. Plastic film is transported through the gap between picking-up film tooth and pallet, and then scraped by unloading impeller to collecting tank. Pallet springs will realize the space of picking-up film tooth and Pallet adapt to the quantity of gathering film. Thus, the film will not be left over, lost and blocked. Also it is ensured the entire remnant mulching film is gathered and delivered to the top of collecting film box. Unloading impeller and guide rail cooperate with each other to unload, so that wrapping film becomes much easier. Picking-up film tooth is able to slide over backwards to the side of film-unloading between the circular rail, and retreat from the circular rail, in order to separate of the picking-up film teeth and the plastic film. Picking-up film agencies, gathering film agencies, unloading film agencies are installed together in bracket fixing. They can adjust the fixing bracket through the angle adjustment lever, change the angle of loosening soil shovel to adapt the requirement. This paper designs and invents a chain guide rail-type plastic film collector which includes the function of picking-up film, gathering film, uploading film and collecting film. Each component of the chain-type plastic film collector is modeled and the virtual assembly is finished by Pro/ENGINEER. At the same time, FEM analysis is carried out to study the stress and deformation of the structure of the key components. The experimental results show that: this machine named the chain guide rail-type plastic film collector can achieve the goal of picking-up film, gathering film, uploading film and collecting film all in one. Under the help of this machine, the gathering film rate is over 92% after the potatoes are harvested. The design solves the difficulty of mechanization in collecting the plastic potato film. Results show that the designed machine is able to pick up plastic film successfully after harvesting potatoes. And it can be applied to other crops as well. Therefore, this paper has both economic and social benefit. ©, 2015, Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering. All right reserved. Source


Cao W.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments | Zhang C.,Shandong Agricultural University | Wang J.,Shandong Agricultural University | Liu S.,Shandong Agricultural University | Xu X.,Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to identify the maize seed purity efficiently, after researching on image processing methods and classification algorithm in terms of the image characteristic of maize seed, a purity identification calculation based on discrete wavelet transform(DWT) and BP neural network was presented. Through this method, the RGB color model character parameters of the maize seed crown part were obtained, then the three color values were processed and analyzed by the two-level DWT. The average of every band was selected as the input samples for BP neural network, and purity identification results of maize seed as the output samples of neural network. Results demonstrated that this method can identify the maize purity effectively with accurate identification rate reaching 94.5%. Source

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