Search results

Porous implant surface is shown to facilitate bone in-growth and cell attachment, improving overall osteointegration, while providing adequate mechanical integrity. Recently, biodegradable material possessing such superior properties has been the focus with an aim of revolutionizing implant’s design, material and performance. This paper aims to present a comprehensive investigation into the design and development of low elastic modulus porous biodegradable Mg-3Si-5HA composite by mechanical alloying and spark plasma sintering (MA-SPS) technique.

This paper presents a comprehensive investigation into the design and development of low elastic modulus porous biodegradable Mg-3Si-5HA composite by MA-SPS technique. As the key alloying elements, HA powders with an appropriate proportion weight 5 and 10 are mixed with the base elemental magnesium (Mg) particles to form the composites of potentially variable porosity and mechanical property. The aim is to investigate the performance of the synthesized composites of Mg-3Si together with HA in terms of mechanical integrity hardness and Young’s moduli corrosion resistance and in-vitro bioactivity.

Mechanical and surface characterization results indicate that alloying of Si leads to the formation of fine Mg2 Si eutectic dense structure, hence increasing hardness while reducing the ductility of the composite. On the other hand, the allying of HA in Mg-3Si matrix leads to the formation of structural porosity (5-13 per cent), thus resulting in low Young’s moduli. It is hypothesized that biocompatible phases formed within the composite enhanced the corrosion performance and bio-mechanical integrity of the composite. The degradation rate of Mg-3Si composite was reduced from 2.05 mm/year to 1.19 mm/year by the alloying of HA elements. Moreover, the fabricated composites showed an excellent bioactivity and offered a channel/interface to MG-63 cells for attachment, proliferation and differentiation.

Overall, the findings suggest that the Mg-3Si-HA composite fabricated by MA and plasma sintering may be considered as a potential biodegradable material for orthopedic application.

Although requirement elicitation is generally acknowledged to be very important in traditional information systems development (ISD), it does not get enough attention in most Web‐based information systems development (WISD). This paper highlighted the difference between ISD and WISD, and proposed a three‐stage model of user requirements elicitation for Web‐based information systems. This model divides the requirements definition into three stages: initial analysis, key user requirements elicitation and regular user responses. Most current WIS design methodologies consider only initial analysis, and neglect actual users’ requirements. Key user input is emphasized in this model, and social network analysis is proposed as a tool for identifying key users. Requirements analysis for WISD is no longer considered a one‐stop step, but is better regarded as a continuous evolving process. Finally, managerial implications are also provided in this paper.

The purpose of this paper is to assess the state of the art of social business process management (Social BPM), explaining applied approaches, existing tools and challenges and to propose a research agenda for encouraging further development of the area.

The methodology comprises a qualitative analysis using secondary data. The approach relies on searches of scientific papers conducted in well-known databases, identifying research work related to Social BPM solutions and those contributing with social characteristics to BPM. Based on the identified papers, the authors selected the most relevant and the latest publications, and categorized their contributions and findings based on open and selective coding. In total, the analysis is based on 51 papers that were selected and analyzed in depth.

Main results show that there are several studies investigating modeling approaches for socializing process activities and for capturing implicit knowledge possessed and used by process actors, enabling to add some kind of flexibility to business processes. However, despite the proven interest in the area, there are not yet adequate tools providing effective solutions for Social BPM. Based on our findings, the authors propose a research agenda comprising three main lines: contributions of social software (SS) to Social BPM, Social BPM as a mechanism for adding flexibility to and for discovering new business processes and Social BPM for enhancing business processes with the use of new technologies. The authors also identify relevant problems for each line.

Some SS tools, like wikis, enable managing social aspects in executing business processes and can be used to coordinate simple business processes. Despite they are commonly used, they are not yet mature tools supporting Social BPM and more efficient tools are yet to appear. The lack of tools preclude organizations from benefitting from implicit knowledge owned by and shared among business process actors, which could contribute to better-informed decisions related to organizational processes. In addition, more research is needed for considering Social BPM as an approach for organizations to benefit from the adoption of new technologies in their business processes.

The paper assesses the state of the art in Social BPM, an incipient area in research and practice. The area can be defined as the intersection of two bigger areas highly relevant for organizations; on the one hand, the management and execution of business processes; and on the other hand, the use of social software, including social media tools, for leveraging on implicit knowledge shared by business process actors to improving efficiency of business processes.

Additively manufactured objects have layered structures, which means post processing is often required to achieve a desired surface finish. Furthermore, the additive nature of the process makes it less accurate than subtractive processes. Hence, additive manufacturing techniques could tremendously benefit from finishing processes to improve their geometric tolerance and surface finish.

Rotary ultrasonic machining (RUM) was chosen as a finishing operation for drilling additively manufactured carbon fiber reinforced polymer (CFRP) composites. Two distinct additive manufacturing methods of fused deposition modeling (FDM) and laser-assisted laminated object manufacturing (LA-LOM) were used to fabricate CFRP plates with continuous carbon fiber reinforcement. The influence of the feedrate, tool rotation speed and ultrasonic power of the RUM process parameters on the aforementioned quality characteristics revealed the feasibility of RUM process as a finishing operation for additive manufactured CFRP.

The quality of drilled holes in the CFRP plates fabricated via LA-LOM was supremely superior to the FDM counterparts with less pullout delamination, smoother surface and less burr formation. The strong interfacial bonding in LA-LOM proven to be superior to FDM was able to endure higher cutting force of the RUM process. The cutting force and cutting temperature overwhelmed the FDM parts and induced higher surface damage.

Overall, the present study demonstrates the feasibility of a hybrid additive and subtractive manufacturing method that could potentially reduce cost and waste of the CFRP production for industrial applications.

The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.

There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.

In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.

The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.

This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.