Recent Patents on Engineering - Volume 12, Issue 2, 2018

Background: Nanoscale zero valent iron (nZVI) is one of the most commonly used nanomaterials for soil and groundwater remediation because of its high reactivity and effective contaminant removal rate. Objective: This paper reviews the methods of nZVI syntheses and effect of nZVI application on contaminants removal, environmental conditions, and microbial growth when anaerobic bioremediation is used for polluted site restoration. Application: Dispersants have been applied to minimize the aggregation of nZVI particles and enhance its migration and influence zone. nZVI has also been applied to enhance the in situ site remediation process. Although there are advantages to combine the nZVI with bioremediation systems, the possible influences caused by the nZVI application contain changes of environmental conditions including the adverse effects on microbial species and diversity. The patents related to the designs of combining nZVI and different types of organic substrates for bioremediation enhancement are summarized in this paper. Future Study: Toxicity evaluation and risk assessment are necessities to minimize the impact of nZVI application on environments and ecosystems.

Background: Fluid flow control techniques gained many advantages when, under the newly coined name fluidics, were found ways of operating without moving or deformed mechanical components. In particular, it became possible to handle fluid motion at very small scales and/or high frequencies. The control signals upon which this motion depends, are often produced by microelectronic devices, also operating without moving components. The transducers from electric to fluidic signals and actions, especially if the latter operate with air, however, cannot so far avoid two-stage indirect conversion, with intermediate mechanical motions of components which are difficult to manufacture, have limited life, and are slow due to mechanical parts inertia. Objective: Development of transducer for direct electric control of flow of air, circumventing the fact that air is electrically neutral and therefore not influenced by voltage or electric current and therefore not influenced by applied voltage or electric current. Methods: The solution is achieved by using ionic wind generated by non-thermal plasma discharge inside cavities the configuration of which correspond to a fluidic bistable diverter amplifier. By using the Coanda effect, the jet of air remains alternatively attached to one of the two attachment walls so that the ionic wind only briefly switches the jet between them. Results: Laboratory models of an electric-to-fluidic transducer were demonstrated to operate reliably with the input electric switching signal voltage increased in a transformer (inexpensive because mass produced for other purposes). The absence of inertia of mechanical components made it possible to operate at quite high switching frequency (above 100 Hz). Conclusion: Patent covering various alternative transducer configurations based on the ionic wind idea was recently grated to the present authors - unfortunately valid only within the boundaries of the Czech Republic.

Background: The finite element method (FEM) has been widely applied in the research of metal machining which can improve the efficiency and reduce the cost of research. 3-D finite element simulation attracts more attention on the research of mechanism and parameter optimization of high-speed machining. Methods: This paper reviews the theses of 3-D finite element simulation in recent years, especially focuses on the key technology of FEM. Some application examples of 3-D finite element simulation in milling, turning and drilling are summarized. The differences of different types of simulation are compared and analyzed and the characters are concluded. In the end, the exiting problem and development direction of 3-D finite element simulation are also discussed. Besides, a lot of patents on 3D finite element simulation for metal machining were studied. Results: The key technology of FEM determines the accuracy of 3-D finite element simulation. And the finite element simulation of different types of processing can be realized by setting different contact and boundary conditions. Conclusion: FEM provides a new approach for the study of mechanism of metal machining. In order to improve the accuracy of 3-D finite element simulation, many researches focus on the improvement of the finite element model. The prediction results of finite element simulation can provide guidance for the parameter optimization of metal machining and the optimum design of tool. And the 3-D finite element simulation is hoped to be more accuracy and efficiency.

Background: Bi2O2CO3 as a typical Aurivillius type bismuth-based layered structure photocatalyst material has received wide attention. It is very important to explore the improving strategy for Bi2O2CO3. Methods: Herein, the preparation methods of Bi2O2CO3 and its application in environmental decontamination were summarized. Patents related to the subject were also reviewed. The modification methods for improving photocatalytic performance of Bi2O2CO3 were also analyzed, including morphology control, doping, fabricating of coupling semiconductors, carbon materials modification and others. Results: Finally, the developments of challenges for the Bi2O2CO3-based photocatalyst were discussed. Conclusion: Furthermore, the study on typical non-metallic oxyacid photocatalyst Bi2O2CO3 will provide fabricating high performance photocatalysts of the similar type for environmental decontamination.

Background: Damage identification at the earliest possible stage is very important for beam structures to ensure safety, extend serviceability, and reduce maintenance costs according to recent patents. Methods: The goal of this work is to develop a virtual load method for beam damage identification by using only the vibration modes of the current structure. Central to the damage identification approach is the construction of the virtual load according to the support conditions of the structure. A virtual quasistatic deformation of the structure can be obtained by multiplying its modal flexibility matrix with the virtual force vector. And then the possible damage location in the structure can be determined by sudden increases in curvatures of the virtual quasi-static deformation. Subsequently the damage extent can be simply computed if necessary. Results: Three types of beams are used as examples to demonstrate the efficiency of the presented virtual load method in structural damage identification. For comparison, damage localization was also conducted by the existing uniform load surface (ULS) curvature method. The results showed that the proposed virtual load method is applicable to all types of beams but the ULS curvature method is only applicable to the simple supported beam. Conclusion: It was found that the proposed method can successfully determine damage location and extent only using the partial modes of the current structure.

Background: Damper bar is an important component to ensure the security and stability operation of generator. Some patents have been proposed in recent years to deal with generator vibration. Based on the damages of damper bars appeared in many hydropower units, the influences of damper bar material on generator operating characteristics are analyzed. Objective: This study aims to find the suitable material for damper bars to improve the reliable operation of generator. Methods: In this research, a 24-MW bulb tubular turbine generator is taken as an example. The two dimensional model is established by using finite element software, and through the comparative analysis of test results and simulation data, the correctness of the model is verified. The analysis and handling of the electromagnetic parameters are based on the finite element method. Results: The brass, copper iron alloy and copper, three kinds of materials are selected to study the effects of damper bar material on the air gap magnetic field and the saturation degree of the pole shoe magnetic density. At the same time, the influences of damper bar material on the generator losses, torques and eddy current are discussed. Conclusion: The application of copper iron alloy material can reduce the saturation degree of the pole shoe magnetic density, pole-to-pole leakage, eddy current and torque ripple of the generator.

Background: Patents revealed that Double Horse Head (DHH) pumping unit is one of the improved models developed from the conventional units, and some unbalanced crank torque may cause high cycle alternating stress which can lead to cracking failure in some key components. This makes the research on simulation of crank torque in beam pumping units a more interesting topic in its maintenance operation. Objective: This paper aims to improve the accuracy of crank torque simulation model for the DHH pumping unit by a parameter optimization method for cable joints. Methods: By using a series of cylinders to model the steel cable, a pumping unit multibody dynamics model was constructed to simulate the crank torque. Then the stiffness and damping coefficient in bushing joint and contact force of cable were treated as the key factors, and a Genetic Algorithms based the method was proposed to optimize them for improving the simulation accuracy of the model. Results: This method was applied to simulate the crank torque of a DHH pumping unit, and the experimental torque was also tested from real unit. Results show that the crank torque simulated from improved model is much closer to the experimental tested torque compared with the original model. Conclusion: The parameter optimization method proposed in this paper greatly improved the accuracy of simulated crank torque in DHH pumping unit multibody dynamics model.

Background: Ultra-wideband (UWB) Impulse Radio (IR) systems have been widely applied to some fields according to the recent patents which coexist with Beidou navigation satellite system (BDS), thus UWB signals may act as a broadband interference to BDS receivers and a threat to disrupt their normal operation. Objective: The study aimed to evaluate the acquisition performance of a BDS receiver with UWB-IR interference, and analyze the processing of UWB-IR signals at the radio frequency (RF) front end of the receiver. Methods: A simulation platform including a Beidou-1 (B1) signal source, a noise module, a software RF front end and an acquisition module was constructed. The power spectral density (PSD) of the B1 signal and UWB-IR signals at the RF front end as well as the processing of UWB signals in time domain was analyzed. Acquisition success rates were measured with UWB interference at different modulation modes, different pulse repetition frequencies (PRFs) and different pulse duty cycles. Results: The RF front end provided no significant suppression of UWB-IR interference in both frequency and time domain. It was shown that a lower UWB PRF and a lower pulse duty cycles improve the acquisition performance. In addition UWB-IR signals with different modulation mode had different interference with the acquisition performance. Conclusion: The acquisition performance of a BDS receiver in the presence of interference from an UWB-IR system was examined. The UWB-IR interference still had an effect on the BDS receiver when the UWB power levels were within the permitted range.

Background: Rock abrasiveness is a factor with considerable influence on the wear of tools in well drilling. However, it is determined with various methods, which result in no uniform standard formed. Objective: The goal of this work is to develop a wear calculation model of PDC compact and a prediction model of rock abrasiveness. Methods: Studies on rock abrasiveness evaluation equipments were carried out in Northeast Petroleum University. Among these patents, one is the device to simulate the wear of drill bit in strata during the real drilling process. Firstly, based on the rock cracking conditions, the force calculation model of the compact is established. Since the actual contact area between the rock and the compact only appears on the tiny part of the apparent area, the real force of particles involved in the wear and the bottom of the compact is obtained according to the probability density distribution of the quartz content. Then, based on the geometrical principle of abrasive wear, the wear calculation model of the compact is established. Finally, the model is modified using the above abrasiveness patent. Results: The model revealed the order of the rock parameters affects the wear of the compact as follows: elastic modulus> quartz content> internal friction angle> surface roughness> Poisson's ratio> cohesion. So the evaluation index of rock abrasiveness was established and the grading standard of rock abrasiveness was developed finally. Conclusion: They can provide guidance for predicting formation abrasiveness and the design and optimization of the drill bit.