Machine vision system for curved surface inspection

This application-oriented paper discusses a non-contact 3D range data measurement system to improve the performance of the existing 2D herring roe grading system. The existing system uses a single CCD camera with unstructured halogen lighting to acquire and analyze the shape of the 2D shape of the herring roe for size and deformity grading. Our system will act as an additional system module, which can be integrated into the existing 2D grading system, providing the additional third dimension to detect deformities in the herring roe, which were not detected in the 2D analysis. Furthermore, the additional surface depth data will increase the accuracy of the weight information used in the existing grading system. In the proposed system, multiple laser light stripes are projected into the herring roe and the single B/W CCD camera records the image of the scene. The distortion in the projected line pattern is due to the surface curvature and orientation. Utilizing the linear relation between the projected line distortion and surface depth, the range data was recovered from a single camera image. The measurement technique is described and the depth information is obtained through four steps: (1) image capture, (2) stripe extraction, (3) stripe coding, (4) triangulation, and system calibration. Then, this depth information can be converted into the curvature and orientation of the shape for deformity inspection, and also used for the weight estimation. Preliminary results are included to show the feasibility and performance of our measurement technique. The accuracy and reliability of the computerized herring roe grading system can be greatly improved by integrating this system into existing system in the future.     

Direct coupling of pulsed radio frequency and pulsed high power in novel pulsed power system for plasma immersion ion implantation

A novel power supply system that directly couples pulsed high voltage (HV) pulses and pulsed 13.56 MHz radio frequency (rf) has been developed for plasma processes. In this system, the sample holder is connected to both the rf generator and HV modulator. The coupling circuit in the hybrid system is composed of individual matching units, low pass filters, and voltage clamping units. This ensures the safe operation of the rf system even when the HV is on. The PSPICE software is utilized to optimize the design of circuits. The system can be operated in two modes. The pulsed rf discharge may serve as either the seed plasma source for glow discharge or high-density plasma source for plasma immersion ion implantation (PIII). The pulsed high-voltage glow discharge is induced when a rf pulse with a short duration or a larger time interval between the rf and HV pulses is used. Conventional PIII can also be achieved. Experiments conducted on the new system confirm steady and safe operation.     

Knowledge through participation: the triumphs and challenges of transferring Integrated Pest and Disease Management (IPDM) technology to cocoa farmers in Papua New Guinea

Income from cocoa is the main source of cash used to purchase food and services in many communities in the tropical lowlands of Papua New Guinea (PNG). Despite the availability of improved management technology, there has been poor transfer and uptake of these technologies among smallholder cocoa farmers, and potentially high bean yields and farmer incomes remain unrealised. A series of IPDM options that were shown to improve crop management and cocoa bean yield in research trials were demonstrated to farmers using an on-farm participatory approach that enabled farmers to evaluate the costs and benefits of each strategy before committing to adoption. The options were designed to provide several levels of entry to improved management, and ranged from no inputs (Option 1), manual inputs (Option 2: pruning, sanitation, weed management and regular complete pod harvesting), high level inputs (Option 3: pruning, sanitation, weed management, regular complete pod harvesting and fertiliser application), to intensive management (Option 4: pruning, sanitation, weed management, regular complete pod harvesting, and the application of fertiliser, fungicide and pesticide). Farmers from East New Britain, Madang and Bougainville, the three main cocoa growing provinces in PNG, participated in on-farm IPDM training and surveys to monitor changes in knowledge and management practice. Farmers opted in or out of the training as their commitments or level of interest changed, and new farmers joined in after observing changes in the cocoa blocks. Farmers were trained in epidemiology and crop management, were shown how to apply the IPDM inputs in their own cocoa blocks, and were given a simple training manual. Surveys conducted prior to, and 3 years after the training, showed an improvement in the farmers’ knowledge of cocoa management and a better understanding of cocoa pest and disease epidemiology. Three years after the training, pest and disease incidence in participating cocoa blocks had declined and cocoa yields had increased by an average of 30%. Trained farmers were encouraged to demonstrate improved management to neighbouring farmers, and the program has now been officially adopted as the national strategy to improve cocoa production in PNG. The participatory approach is an effective way of disseminating information and technology to farmers, however, it requires frequent follow-up visits by trained extension staff. We also discuss the significant challenges associated with conducting farmer surveys.     

三点弯曲法的PBGA封装实验测试

任何电子产品在进入市场之前的可靠性测试是十分重要的环节。为此,在之前的几十年中开发了多种类型的测试方法。一种广泛使用的测试方法便是线路板弯曲测试。进行可靠性测试的一个主要问题就是需要大量的测试样品,这是因为这种测试必须重复进行直到获得一致并满意的测量结果。其测试样品的设计,组装工艺和测试程序需要花费长期的时间。如果可靠性测试结果不满意,测试样品需要重新设计、重新生产、重新测试,这从商业的观点来看成本过高且低效。为简化可靠性测试程序,提出了计算模拟的方法在前期设计阶段来预测印制板组装线的可靠性。在目前的研究中,可靠性测试采用了三点弯曲测试法。实现了有限元模式确认及关于该模式应用的2种情况研究。     

An investigation on the effect of varying the load, mesh and simulation parameters in microwave heating applications.

The paper attempts to provide a generic proposal on the influence of various microwave load parameters based on results accumulated during an investigation using a specific microwave multimode heating cavity configuration. The results have been obtained by numerical analysis using the Finite Element Method within a 3-D environment. The load parameters considered were dielectric constant, loss factor, load thickness and load position. Load material properties are typical of those used in industrial relevant applications. Of the four load parameters investigated, the configuration with a high loss factor was seen to dominate the load impact regardless of load thickness, load position or dielectric constant. With decreasing loss factor or increasing load thickness, the influence of the dielectric constant increases. Minor adjustments in the load position (10%) is generally seen to have minimal impact for all load properties considered. The paper also investigates the numerical impact of varying load properties. As the dielectric constant increases, which requires a higher number of mesh elements, so does the average iterations per numerical cycle. The number of numerical cycles and time to reach a convergence is also seen to be inversely proportional to the load loss factor.     

A state vector approach to the one dimensional consolidation of multi-layer soils

A method for determining the behaviour of a one-dimensional multi-layer soil under consolidation is described. A state vector whose components are the excess pore water pressure and discharge velocity is defined. It is shown that problems associated with the enforcement of continuity conditions at the inter-layer boundaries are thereby substantially removed. The time dependent behaviour of the settlement and excess pore water pressure is determined by numerically inverting the Laplace transform (with respect to the time) of the state vector. Examples of the numerical performance of the method are given and numerical comparisons are made with a finite element solution to the problem.     

A multivariate analysis of the effects of the Self-Directed Search on high school girls.

Attempted to learn how the Self-Directed Search (SDS) achieves its effects: Are the effects of the SDS on students due largely to its transparent structure and the large number of occupational options presented? Can these effects be enhanced if students are given an instructional booklet about the SDS and J. L. Holland's typology? These hypotheses were investigated in a Structure?×?Options?×?Instruction design with 104 high school girls randomly assigned to the 8 conditions. Ss were assessed before and 2 mo after treatment for their vocational aspirations, knowledge of the typology, and information seeking. The nonsignificant findings imply that the SDS achieves its effects partly because of its numerous occupational options and that the use of an instructional booklet may also increase the number of options. Some speculations about the influence of counselors and interest inventories are offered. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Achieving Microparticles with Cell‐Instructive Surface Chemistry by Using Tunable Co‐Polymer Surfactants

A flow‐focusing microfluidic device is used to produce functionalized monodisperse polymer particles with surface chemistries designed to control bacterial biofilm formation. This is achieved by using molecularly designed bespoke surfactants synthesized via catalytic chain transfer polymerization. This novel approach of using polymeric surfactants, often called surfmers, containing a biofunctional moiety contrasts with the more commonly employed emulsion methods. Typically, the surface chemistry of microparticles are dominated by unwanted surfactants that dilute/mask the desired surface response. Time of flight secondary ion mass spectrometry (ToF‐SIMS) analysis of particles demonstrates that the comb‐graft surfactant is located on the particle surface. Biofilm experiments show how specifically engineered surface chemistries, generated by the surfactants, successfully modulate bacterial attachment to both polymer films, and microparticles. Thus, this paper outlines how the use of designed polymeric surfactants and droplet microfluidics can exert control over both the surface chemistry and size distribution of microparticle materials, demonstrating their critical importance for controlling surface‐cell response.     

Effect of Aging Treatment on the Microstructure and Resistivity of a Nickel-Base Superalloy

The γ′ precipitation behavior of age-hardened WASPALOY, aged at 998 K, 1073 K, and 1148 K (725 °C, 800 °C, and 875 °C) for times ranging from 0.5 to 263.5 hours, were evaluated via analysis of ultra small angle X-ray scattering (USAXS) curves and scanning electron microscopy (SEM) micrographs. The USAXS spectra revealed a single precipitate size distribution at the earliest aging times, which evolves into a bimodal precipitate size distribution at later aging times. The primary precipitate radius displayed t ^1/3 coarsening dependence for aging at 1073 K and 1148 K (800 °C and 875 °C); however, the primary radius increased with t ^0.4 dependence at 998 K (725 °C), most likely due to mixed growth and coarsening. A figure of merit, η′, consisting of two terms, one associated with precipitate size and volume fraction and the other with compositional fluctuations, was proposed. η′ shows direct empirical correlations with changes in the measured electrical resistivity.