Adverse reactions of amiodarone

Adverse drug reaction is defined by the World Health Organization as any response to a drug that is noxious and unintended and occurs at a dose normally used in man. Older people are at elevated risk of adverse drug reactions-because of changes in pharmacodynamics, concurrent use of multiple medications and the related drug interactions. However, adverse drug reactions are significantly underestimated in the elderly population that is also exposed to inappropriate drugs. Amiodarone is an antiarrhythmic drug used commonly for the treatment of atrial fibrillation and is increasingly prescribed in older people. While amiodarone is an efficient drug for rhythm control, it's a carrier of different adverse reactions, and pro and cons must be carefully evaluated before its use especially in older people

Experimental analysis of residual stresses on AlSi10Mg parts produced by means of Selective Laser Melting (SLM)

Abstract During the Selective Laser Melting (SLM) process, the scanned layers are subjected to rapid thermal cycles. Steep temperature gradients generate residual stresses. Residual stresses can be detrimental to the proper functioning and the structural integrity of built parts. In this paper, the semi-destructive hole-drilling method has been used to measure the residual stresses on AISi10Mg parts after building, stress relieving and shot-peening, respectively. The outcomes have shown the presence, on the as-built components, of high tensile stresses that the usual post-processing operations are not able to minimize. The adopted method has proved to be a suitable tool to identify optimal process parameters for each step of the production cycle

Dental Failure Analysis: The Need of a Comprehensive Failure Classification

For more than thirty percent of patients with implant-supported fixed dental prosthesis, various complications can be observed over five-years of function. In some cases, failure can be ascribed to mechanical reasons such as loosening of the retaining screws or fracture of the implant components. The paper evaluates three different failures of implant-supported prostheses. All cases were analyzed by optical and SEM microscopy to identify the failure modes and the possible failure causes. Improper design or errors in finishing operations or in assembly are identified as dental failure causes. A matrix classification is proposed to collect rupture cases of implant-supported prostheses

On the Effect of Part Orientation on Stress Distribution in AlSi10Mg Specimens Fabricated by Laser Powder Bed Fusion (L-PBF)

Abstract The freedom of design of AM products suffers from some limitations in case of powder bed metal processes, because AM part's integrity is affected by the residual stress state that is a consequence of the thermal history during part fabrication. Aim of this work is to evaluate the effect of part orientation on stress distribution. Thus, flat samples of AlSi10Mg alloy built along different orientations are produced by means of laser powder bed fusion (L-PBF) process, also known as Selective Laser Melting (SLM). Then, the semi-destructive hole-drilling method is used to evaluate residual stresses beneath the surfaces of samples. The outcomes of the study can be exploited to define design rules in order to both minimize support structures and optimize the orientation of the part in the building volume

The Use of Self-replicated Parts for Improving the Design and the Accuracy of a Low-cost 3D Printer

Abstract Low-cost entry-level 3D printers suffer from reduced optimization, that is a consequence of development cost savings. A student challenge was used to modify four Prusa i3 machines with the aim of enhancing the design and performances by means of self-replicated parts. The challenge results were assessed through benchmarking of the four modified 3D printers, whose dimensional accuracy was evaluated by means of CMM measurements of 3D printed replicas of a reference part. The ISO IT grades related to the dimensional quality of the replicas were considered in the analysis of the CMM measures for the challenge assessment

Enhancing the dimensional accuracy of a low-cost 3D printer

3D printing is widely used in the entertainment industry by filmmakers, effect studios and game designers to easily and fast fabricate characters or objects that are first virtually modelled through Computer Graphics. There are several commercial proposals in the field of low-cost 3D printers, with prices starting from a few hundred euros for kits that the users should assemble by themselves. However, their performances in terms of part accuracy are quite limited and are basically the consequence of a lack of optimization both in mechanical terms as in software. Starting from these considerations, an optimization project was assigned to the students of the Specializing Master in Industrial Automation of the Politecnico di Torino. The Master is developed in collaboration with COMAU S.p.a., a company worldwide leader in automation expecially for the automotive sector. The task of enhancing the performances of the 3D printer Prusa i3, that is supplied in the assembly box, was assigned to sixteen engineers attending the Master who were divided into 4 groups. The activities have led to the birth of four new 3D printers: Fluo, Ghost, Metallica and Print-Doh. In order to assess and validate the improvements, a benchmarking activity was carried out to evaluate the dimensional accuracy of the four printers. The benchmarking was based on the manufacturing of an innovative reference artifact whose geometrical features are designed to fit within different ISO basic sizes. Each group printed a replica of the reference part with their own new printer and then the replicas were measured by means of a coordinate measuring machine (CMM). Measures were used to compare the performances of the four printers and the results of the benchmarking considers the dimensional accuracy of the replicas in terms of ISO IT grades, but also the form errors of the geometrical features through GD&T tolerances

A methodology for evaluating the aesthetic quality of 3D printed parts

Abstract Nowadays, 3D printing is recognized as one of the key technologies that enables the distributed manufacturing adoption. However, inexperienced people might perceive this technology as far from easy user-usability because of evident aesthetic defects on 3D printed parts. In this paper, an indicator-based methodology is proposed for the assessment and the ranking of the aesthetic capability of 3D printers by evaluating the ability of a 3D printer to reproduce a reference part without defects. The reference part includes several geometric features that characterize most of as-built aesthetic defects. In addition, a benchmarking analysis was carried out to show an example of the methodology applied to three different machines

Residual stress investigation on Ti-48Al-2Cr-2Nb samples produced by Electron Beam Melting process

Abstract Ti-48Al-2Cr-2Nb (Ti-48-2-2) is an intermetallic alloy belonging to a family of gamma-TiAl intermetallic alloys that are attracting significant attention. Electron Beam Melting (EBM) process is today the only manufacturing process that allows effective production of parts made by these kinds of alloys. Proper process control avoids high temperatures in the surrounding areas that may generate significant residual stresses that could cause micro-cracks. In this paper, an investigation on the residual stress state on Ti-48-2-2 parts is carried out using the hole drilling method. In particular, the influence of EBM process parameters is evaluated in order to understand the effects of the residual stresses on part integrity

machining induced residual stresses in alsi10mg component produced by laser powder bed fusion l pbf

Abstract The adoption of metal powder-based laser process (L-PBF) for industrial applications continues to widen, due to an increasing knowledge on additive processes and the availability of new systems for industrial production. The use of L-PBF processes requires a deeper investigation and comparison on mechanical properties of conventional and additive parts. For instance, metal parts produced by L-PBF could require additional machining operations, which alter the stress state of additive components. In this work, the effect of machining operations on the residual stress state of an AlSi10Mg component produced by L-PBF is investigated by means of the semi destructive hole-drilling method