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11 – 20 of 129Diana Irinel Baila, Filippo Sanfilippo, Tom Savu, Filip Górski, Ionut Cristian Radu, Catalin Zaharia, Constantina Anca Parau, Martin Zelenay and Pacurar Razvan
The development of new advanced materials, such as photopolymerizable resins for use in stereolithography (SLA) and Ti6Al4V manufacture via selective laser melting (SLM…
Abstract
Purpose
The development of new advanced materials, such as photopolymerizable resins for use in stereolithography (SLA) and Ti6Al4V manufacture via selective laser melting (SLM) processes, have gained significant attention in recent years. Their accuracy, multi-material capability and application in novel fields, such as implantology, biomedical, aviation and energy industries, underscore the growing importance of these materials. The purpose of this study is oriented toward the application of new advanced materials in stent manufacturing realized by 3D printing technologies.
Design/methodology/approach
The methodology for designing personalized medical devices, implies computed tomography (CT) or magnetic resonance (MR) techniques. By realizing segmentation, reverse engineering and deriving a 3D model of a blood vessel, a subsequent stent design is achieved. The tessellation process and 3D printing methods can then be used to produce these parts. In this context, the SLA technology, in close correlation with the new types of developed resins, has brought significant evolution, as demonstrated through the analyses that are realized in the research presented in this study. This study undertakes a comprehensive approach, establishing experimentally the characteristics of two new types of photopolymerizable resins (both undoped and doped with micro-ceramic powders), remarking their great accuracy for 3D modeling in die-casting techniques, especially in the production process of customized stents.
Findings
A series of analyses were conducted, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, mapping and roughness tests. Additionally, the structural integrity and molecular bonding of these resins were assessed by Fourier-transform infrared spectroscopy–attenuated total reflectance analysis. The research also explored the possibilities of using metallic alloys for producing the stents, comparing the direct manufacturing methods of stents’ struts by SLM technology using Ti6Al4V with stent models made from photopolymerizable resins using SLA. Furthermore, computer-aided engineering (CAE) simulations for two different stent struts were carried out, providing insights into the potential of using these materials and methods for realizing the production of stents.
Originality/value
This study covers advancements in materials and additive manufacturing methods but also approaches the use of CAE analysis, introducing in this way novel elements to the domain of customized stent manufacturing. The emerging applications of these resins, along with metallic alloys and 3D printing technologies, have brought significant contributions to the biomedical domain, as emphasized in this study. This study concludes by highlighting the current challenges and future research directions in the use of photopolymerizable resins and biocompatible metallic alloys, while also emphasizing the integration of artificial intelligence in the design process of customized stents by taking into consideration the 3D printing technologies that are used for producing these stents.
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Wenxiong Lin, Huagang Liu, Haizhou Huang, Jianhong Huang, Kaiming Ruan, Zixiong Lin, Hongchun Wu, Zhi Zhang, Jinming Chen, Jinhui Li, Yan Ge, Jie Zhong, Lixin Wu and Jie Liu
The purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the oxygen-permeable…
Abstract
Purpose
The purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the oxygen-permeable window, which is prepared by irradiating polyethylene terephthalate membranes with accelerated heavy ions.
Design/methodology/approach
Experimental approaches are carried out to characterize printing parameters of resins with different photo-initiator concentrations by a photo-polymerization matrix, to experimentally observe and theoretically fit the oxygen inhibition layer thickness during printing under conditions of pure oxygen and air, respectively, and to demonstrate the enhanced CLIP processes by using pure oxygen and air, respectively.
Findings
Owing to the high permeability of track-etched membrane, CLIP process is demonstrated with printing speed up to 800 mm/h in the condition of pure oxygen, which matches well with the theoretically predicted maximum printing speed at difference light expose. Making a trade-off between printing speed and surface quality, maximum printing speed of 470 mm/h is also obtained even using air. As the oxygen inhibition layer created by air is thinner than that by pure oxygen, maximum speed cannot be simply increased by intensifying the light exposure as the case with pure oxygen.
Originality/value
CLIP process is capable of building objects continuously instead of the traditional layer-by-layer manner, which enables tens of times improvement in printing speed. This work presents an enhanced CLIP process by first using a porous track-etched membrane to serve as the oxygen permeable window, in which a record printing speed up to 800 mm/h using pure oxygen is demonstrated. Owing to the high permeability of track-etched membrane, continuous process at a speed of 470 mm/h is also achieved even using air instead of pure oxygen, which is of significance for a compact robust high-speed 3D printer.
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Xin Hu and Xi‐bin Cao
To improve the accuracy of mapping of space‐borne three‐line array cameras.
Abstract
Purpose
To improve the accuracy of mapping of space‐borne three‐line array cameras.
Design/methodology/approach
Derivation of the mathematical model and the error model of the three‐line aerial triangulation, the creation of the simulation data, and the analysis and comparison of the simulating result error.
Findings
When using the photographs, which are acquired by adopting the traditional three‐line array cameras, to map without control, there exists the problem that the accuracy cannot satisfy the requirement.
Research limitations/implications
Do not need the ground control points, and can realize the mapping without control. It is of practical application value to the mapping of stars such as the Moon, Mars.
Practical implications
By adding four small matrix CCDs to the traditional three‐line array cameras, and using the effect of the small matrix, controlling the location of the real photograph point, it can improve the accuracy.
Originality/value
Put forward the LMCCD concept of the combination of the three‐linear and the matrix cameras, and validate in theory.
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A proliferation of optical products has resulted from the need to find a replacement for microfilm for storing images, to improve mass data storage technologies and to gain…
Abstract
A proliferation of optical products has resulted from the need to find a replacement for microfilm for storing images, to improve mass data storage technologies and to gain control over the distribution of commercial databases. Developers of CD‐ROM products need to follow a strategy that includes the following principles: (1) Focus on innovation rather than the technology; (2) Determine customers' needs; (3) Become expert in the available technologies; (4) Make a commitment to excellence; (5) Prepare a strategic plan; (6) Get a head‐start on the competition. Companies that have already been successful in CD‐ROM product development include R.R. Bowker, Disclosure and General Motors. The chances for success are greater for companies that can introduce new products and services frequently. Several companies have developed families of CD‐ROMs with a common interface, giving multiple users access to the information at the same time.
Dong Mei and Zhu-Qing Yu
This paper aims to study a disturbance rejection controller to improve the anti-interference capability and the position tracking performance of airborne radar stabilized platform…
Abstract
Purpose
This paper aims to study a disturbance rejection controller to improve the anti-interference capability and the position tracking performance of airborne radar stabilized platform that ensures the stability and clarity of synthetic aperture radar imaging.
Design/methodology/approach
This study proposes a disturbance rejection control scheme for an airborne radar stabilized platform based on the active disturbance rejection control (ADRC) inverse estimation algorithm. Exploiting the extended state observer (ESO) characteristic, an inversely ESO is developed to inverse estimate the unmodeled state and extended state of the platform system known as total disturbances, which greatly improves the estimation performance of the disturbance. Then, based on the inverse ESO result, feedback the difference between the output of the tracking differentiator and the inverse ESO result to the nonlinear state error feedback controller (NLSEF) to eliminate the effects of total disturbance and ensure the stability of the airborne radar stabilized platform.
Findings
Simulation experiments are adopted to compare the performance of the ADRC inverse estimation algorithm with that of the proportional integral derivative controller which is one of the mostly applied control schemes in platform systems. In addition, classical ADRC is compared as well. The results have shown that the ADRC inverse estimation algorithm has a better disturbance rejection performance when disturbance acts in airborne radar stabilized platform, especially disturbed by continuous airflow under some harsh air conditions.
Originality/value
The originality of this paper is exploiting the ESO characteristic to develop an inverse ESO, which greatly improves the estimation performance of the disturbance. And the ADRC inverse estimation algorithm is applied to ameliorate the anti-interference ability of the airborne radar stabilization platform, especially the ability to suppress continuous interference under complex air conditions.
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Riyaz Ali Shaik and Elizabeth Rufus
This paper aims to review the shape sensing techniques using large area flexible electronics (LAFE). Shape perception of humanoid robots using tactile data is mainly focused.
Abstract
Purpose
This paper aims to review the shape sensing techniques using large area flexible electronics (LAFE). Shape perception of humanoid robots using tactile data is mainly focused.
Design/methodology/approach
Research papers on different shape sensing methodologies of objects with large area, published in the past 15 years, are reviewed with emphasis on contact-based shape sensors. Fiber optics based shape sensing methodology is discussed for comparison purpose.
Findings
LAFE-based shape sensors of humanoid robots incorporating advanced computational data handling techniques such as neural networks and machine learning (ML) algorithms are observed to give results with best resolution in 3D shape reconstruction.
Research limitations/implications
The literature review is limited to shape sensing application either two- or three-dimensional (3D) LAFE. Optical shape sensing is briefly discussed which is widely used for small area. Optical scanners provide the best 3D shape reconstruction in the noncontact-based shape sensing; here this paper focuses only on contact-based shape sensing.
Practical implications
Contact-based shape sensing using polymer nanocomposites is a very economical solution as compared to optical 3D scanners. Although optical 3D scanners can provide a high resolution and fast scan of the 3D shape of the object, they require line of sight and complex image reconstruction algorithms. Using LAFE larger objects can be scanned with ML and basic electronic circuitory, which reduces the price hugely.
Social implications
LAFE can be used as a wearable sensor to monitor critical biological parameters. They can be used to detect shape of large body parts and aid in designing prosthetic devices. Tactile sensing in humanoid robots is accomplished by electronic skin of the robot which is a prime example of human–machine interface at workplace.
Originality/value
This paper reviews a unique feature of LAFE in shape sensing of large area objects. It provides insights from mechanical, electrical, hardware and software perspective in the sensor design. The most suitable approach for large object shape sensing using LAFE is also suggested.
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Dai Cheng, Haihong Zhu and Linda Ke
This paper aimed to investigate the plasma characteristics of selective laser micro sintering Cu‐based metal powder using spectra method.
Abstract
Purpose
This paper aimed to investigate the plasma characteristics of selective laser micro sintering Cu‐based metal powder using spectra method.
Design/methodology/approach
Temporal and time integrating plasma induced during selective laser micro sintering Cu‐based metal powder with a Q‐switched pulsed YAG laser have been detected and analyzed. Boltzmann plot and Stark broadening of the spectra line are utilized to analyze the electron temperature and density, respectively. The influences of the Q‐switching rate and duration on the plasma temperature and electron density have been investigated.
Findings
The results show that the plasma temperature decreases from 9,600 to 9,000 K with the increase of the Q‐switching rate from 5 to 35 kHz if Q‐switching duration of laser is kept at a constant value. The plots of temporal temperature and electron density show that the electron density varies in a faster speed than plasma temperature and the entire expansion process takes about 700 ns‐1 μs in this experiment. Evolutional images of the plasma plume using Q‐switching rate of 5 kHz and 5 μs have been registered by the ICCD with a 10 ns exposure time, which shows that the plasma plume takes about 100 ns to get to the maximum size and 600 ns to disperse.
Originality/value
The plasma spectra of selective laser micro sintering Cu‐based metal powder have been diagnosed experimentally. The plasma characteristics of selective laser micro sintering Cu‐based metal powder have been analyzed.
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Alaaldeen Al-Halhouli, Hala Qitouqa, Abdallah Alashqar and Jumana Abu-Khalaf
This review paper aims to introduce the inkjet printing as a tool for fabrication of flexible/wearable sensors. It summarizes inkjet printing techniques including various modes of…
Abstract
Purpose
This review paper aims to introduce the inkjet printing as a tool for fabrication of flexible/wearable sensors. It summarizes inkjet printing techniques including various modes of operation, commonly used substrates and inks, commercially available inkjet printers and variables affecting the printing process. More focus is on the drop-on-demand printing mode, a strongly considered printing technique for patterning conductive lines on flexible and stretchable substrates. As inkjet-printed patterns are influenced by various variables related to its conductivity, resistivity, durability and dimensions of printed patterns, the main printing parameters (e.g. printing multilayers, inks sintering, surface treatment, cartridge specifications and printing process parameters) are reported. The embedded approaches of adding electronic components (e.g. surface-mounted and optoelectronic devices) to the stretchable circuit are also included.
Design/methodology/approach
In this paper, inkjet printing techniques for fabrication of flexible/stretchable circuits will be reviewed. Specifically, the various modes of operation, commonly used substrates and inks and variables affecting the printing process will be presented. Next, examples of inkjet-printed electronic devices will be demonstrated. These devices will be compared to their rigid counterpart in terms of ease of implementation and electrical behavior for wearable sensor applications. Finally, a summary of key findings and future research opportunities will be presented.
Findings
In conclusion, it is evident that the technology of inkjet printing is becoming a competitor to traditional lithography fabrication techniques, as it has the advantage of being low cost and less complex. In particular, this technique has demonstrated great capabilities in the area of flexible/stretchable electronics and sensors. Various inkjet printing methods have been presented with emphasis on their principle of operation and their commercial availability. In addition, the components of a general inkjet printing process have been discussed in details. Several factors affect the resulting printed patterns in terms of conductivity, resistivity, durability and geometry.
Originality/value
The paper focuses on flexible/stretchable optoelectronic devices which could be implemented in stretchable circuits. Furthermore, the importance and challenges related to printing highly conductive and highly stretchable lines, as well as reliable electronic devices, and interfacing them with external circuitry for power transmission, data acquisition and signal conditioning have been highlighted and discussed. Although several fabrication techniques have been recently developed to allow patterning conductive lines on a rubber substrate, the fabrication of fully stretchable wearable sensors remains limited which needs future research in this area for the advancement of wearable sensors.
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Marc Wouters and Susana Morales
To provide an overview of research published in the management accounting literature on methods for cost management in new product development, such as a target costing, life…
Abstract
Purpose
To provide an overview of research published in the management accounting literature on methods for cost management in new product development, such as a target costing, life cycle costing, component commonality, and modular design.
Methodology/approach
The structured literature search covered papers about 15 different cost management methods published in 40 journals in the period 1990–2013.
Findings
The search yielded a sample of 113 different papers. Many contained information about more than one method, and this yielded 149 references to specific methods. The number of references varied strongly per cost management method and per journal. Target costing has received by far the most attention in the publications in our sample; modular design, component commonality, and life cycle costing were ranked second and joint third. Most references were published in Management Science; Management Accounting Research; and Accounting, Organizations and Society. The results were strongly influenced by Management Science and Decision Science, because cost management methods with an engineering background were published above average in these two journals (design for manufacturing, component commonality, modular design, and product platforms) while other topics were published below average in these two journals.
Research Limitations/Implications
The scope of this review is accounting research. Future work could review the research on cost management methods in new product development published outside accounting.
Originality/value
The paper centers on methods for cost management, which complements reviews that focused on theoretical constructs of management accounting information and its use.
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