Hung-Yao Hsu

This article applies nonlinear regression method in characterizing a lossy piezoelectric material, i.e. PVDF (polyvinylidene fluoride), which has been widely used for ultrasonic transducer design. The characterization is based on the measurement of electrical impedance. A computer based data acquisition system is built to collect the data. The fitting process is then applied to the collected data. The best fit parameters are achieved at the selected frequency range, which is in good agreement between the modeled impedance curve and experimental data points at resonance region. The whole data collection and evaluation process can be easily and fast implemented within a few minutes. The design and simulation of piezoelectric materials based MEMS ultrasonic transducer is one of the motivations for developing this method. The evaluated piezoelectric material parameters will be imported to the later transducer modeling to improve the design accuracy of MEMS devices with a reduced design period.

Stretchable nanomaterial-based strain sensors are essential to soft electronics and robotics and wearable devices. A sensitivity graph for those reported highly stretchable sensors is often divided into a few nearly linear zones resulting in several gauge factors, which poses a challenge for calibration. We herein report that (i) a gauge factor does not have to be one constant number because calibration merely relies on the relationship between the input and the output data and (ii) calibration accuracy relates to linear regression analysis between testing data and a fitted graph, i.e. calibration accuracy corresponding to coefficient of determination (R²). It is the first time that a stretchable strain sensor is reported as a gauge, where the resolution is an essential element of a gauge. A stretchable elastomer/graphene strain sensor developed in this study is calibrated as a proper gauge to provide strain readings with high resolution up to 0.089% and accuracy of over 99.7%, where resolution refers to the minimum dimension of accurate measurement. The idea of calibration in this study could advance many published wearable sensors to gauges. Sensing parameters are also provided with practical meanings for calibration.

Electrical power is considered as a significant part of contemporary life, and an essential element for development. Fossil fuels have been utilized since the beginning of the twentieth century for electricity generation. However, fossil fuels depletion at the escalating pace as well as their formidable negative implications upon ecosystem contributed to increasing interest in harnessing renewable energy sources for producing electric power to meet the growing demand worldwide. In Iraq, the electrical supply is not sufficient to supply 12 hours a day of electricity. Many rural areas, particularly their schools are suffering from the electricity shortage such as Umm Qasr Primary School that located 20 km away from the city centre of Karbala city in the middle of Iraq. In order to overcome this issue, this paper proposes a hybrid system which relies on renewable resources and the local grid to electrify Umm Qasr Primary School. Various combinations of energy resources have been analysed by using HOMER software to estimate an optimum hybrid system. The analysis illustrates that the optimal configuration of the projected system is composed of 22.4 kW PV modules, 59 batteries, and 5738kWh purchased from the local grid which has reduced the net present cost(NPC)from US$ 163791 the current situation to US$60,420 for the proposed system. The simulation findings also demonstrate that detrimental emissions have been reduced significantly.

Owing to the fact that the global warming and climate change has a worsening trend due to the steadily greenhouse gas (GHG) emission from generating electricity to support the blooming economic activities and transportation needs. There is an ever-growing concern of reducing the GHG emission by investigating the potential of increasing energy production from various renewable energy sources. In this paper, the feasibility of implementing a household hybrid renewable energy system including the solar, biomass, wind turbine systems are presented.

Cell culture and cell scaffold engineering have previously developed in two directions. First can be ‘static into dynamic’, with proven effects that dynamic cultures have benefits over static ones. Researches in this direction have used several mechanical means, like external vibrators or shakers, to approximate the dynamic environments in real tissue, though such approaches could only partly address the issue. Second, can be ‘2D into 3D’, that is, artificially created three-dimensional (3D) passive (also called ‘static’) scaffolds have been utilized for 3D cell culture, helping external culturing conditions mimic real tissue 3D environments in a better way as compared with traditional two-dimensional (2D) culturing. In terms of the fabrication of 3D scaffolds, 3D printing (3DP) has witnessed its high popularity in recent years with ascending applicability, and this tendency might continue to grow along with the rapid development in scaffold engineering. In this review, we first introduce cell culturing, then focus 3D cell culture scaffold, vibration stimulation for dynamic culture, and 3DP technologies fabricating 3D scaffold. Potential interconnection of these realms will be analyzed, as well as the limitations of current 3D scaffold and vibration mechanisms. In the recommendation part, further discussion on future scaffold engineering regarding 3D vibratory scaffold will be addressed, indicating 3DP as a positive bridging technology for future scaffold with integrated and localized vibratory functions.

The categorization of cell culture chiefly includes two aspects; one is the dimensionality and another regards the dynamicity. Referring to knowledge of “engineering system evolution”, 2D toward 3D cell culture follows the direction of evolution in dimensionality, and 3D scaffolds with 3DP as its popular fabrication tools has played a role in 3D cell culture applications. Dynamic methods of cell culturing, compared with traditional static means, generally follow the evolution line “static to motional or dynamic”, and vibration has been selected frequently as the suitable tool to achieve the dynamicity of cell culture. Although such a scaffold plus vibration approach has benefited cell culture, there exist significant defects. To mitigate some existing gaps, as well as following further evolutionary trends, the concept of the 3D printed vibratory scaffold (3DPVS) used in cell culture applications is firstly brought out in this study. With 3DPVS, a 3D scaffold in traditional scaffold engineering could potentially evolve into a novel vibratory scaffold which will play significant role in future bioengineering and scaffold engineering. Since 3DPVS’s development remains blank, designers firstly need to propose a high-quality conceptual design; the process of identifying design methodology is challenging since there has been no formal methodology applied for scaffold design. To address these issues, a new design approach is proposed in this paper, which includes an integral development process and focuses on the 3DPVS conceptual stage. The possible methodology and tools to achieve the established conceptual design in following step will be also be discussed.

The main issue of vison-based automatic harvesting manipulators is the difficulty in the correct fruit identification in the images under natural lighting conditions. Mostly, the solution has been based on a linear combination of color components in the multispectral images. However, the results have not reached a satisfactory level. To overcome this issue, this paper proposes a robust nonlinear fusion method to augment the original color image with the synchronized near infrared image. The two images are fused with Daubechies wavelet transform (DWT) in a multiscale decomposition approach. With DWT, the background noises are reduced and the necessary image features are enhanced by fusing the color contrast of the color components and the homogeneity of the near infrared (NIR) component. The resulting fused color image is classified with a C-means algorithm for reconstruction. The performance of the proposed approach is evaluated with the statistical F measure in comparison to some existing methods using linear combinations of color components. The results show that the fusion of information in different spectral components has the advantage of enhancing the image quality, therefore improving the classification accuracy in citrus fruit identification in natural lighting conditions.