Additive manufacturing of metallic components – Process, structure and properties

Unlike conventional materials removal methods, additive manufacturing (AM) is based on a novel materials incremental manufacturing philosophy. Additive manufacturing implies layer by layer shaping and consolidation of powder feedstock to arbitrary configurations, normally using a computer controlled laser. The current development focus of AM is to produce complex shaped functional metallic components, including metals, alloys and metal matrix composites (MMCs), to meet demanding requirements from aerospace, defence, automotive and biomedical industries. Laser sintering (LS), laser melting (LM) and laser metal deposition (LMD) are presently regarded as the three most versatile AM processes. Laser based AM processes generally have a complex non-equilibrium physical and chemical metallurgical nature, which is material and process dependent. The influence of material characteristics and processing conditions on metallurgical mechanisms and resultant microstructural and mechanical properties of AM proc...

Laser additive manufacturing of metallic components: materials, processes and mechanisms

A study of the microstructural evolution during selective laser melting of Ti–6Al–4V

Topological design and additive manufacturing of porous metals for bone scaffolds and orthopaedic implants: A review.

https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1037&context=mepubs

Additive manufacturing of Ti6Al4V alloy: A review

Structural, mechanical and in vitro characterization of individually structured Ti-6Al-4V produced by direct laser forming.

Medical Education 2010:44:148–155



Objectives  This study (a post-intervention assessment) was designed to assess the effectiveness of peer-assisted learning (PAL) using student-teachers (STs) with limited training to teach complicated technical skills for interpreting ultrasound images of the shoulder.



Methods  Students in Years 3 and 4 of medical school were randomly assigned to two groups. In the PAL group (PG), teaching was delivered by a group of nine STs from Years 3 and 4, who undertook a 30-minute general training and 1 week of self-teaching. In the staff-led group (SG), students were taught by a group of three ultrasound-experienced doctors. Exposure took place in two separate lessons (each of 120 minutes) and introduced eight standard sectional planes (EULAR) using a 10-MHz Nemio™ XG system (Toshiba Medical Systems GmbH). The theoretical and practical learning outcomes were tested using a multiple-choice question (MCQ) test and an objective structured clinical examination (OSCE). Qualitative differences were evaluated using Likert scale-based items.



Results  Evaluation of differences between the PG (n = 75) and SG (n = 76) in the theoretical (MCQ score; P = 0.644) and practical (total OSCE score; P = 0.133) outcomes showed no difference between the two groups. However, the STs themselves showed significantly better results overall (P < 0.05). Staff members were rated more highly than STs, especially on items relating to competence (P < 0.05).



Conclusions  Complicated technical skills can be adequately taught to students using the PAL system by STs with limited training. Self-teaching learning strategies are successful in contexts of limited teacher training. However, despite positive objective results, STs still face prejudice from students with regard to competency.

Peer teaching: a randomised controlled trial using student‐teachers to teach musculoskeletal ultrasound

OBJECTIVES This study (a post-intervention assessment) was designed to assess the effectiveness of peer-assisted learning (PAL) using student-teachers (STs) with limited training to teach complicated technical skills for interpreting ultrasound images of the shoulder. METHODS Students in Years 3 and 4 of medical school were randomly assigned to two groups. In the PAL group (PG), teaching was delivered by a group of nine STs from Years 3 and 4, who undertook a 30-minute general training and 1 week of self-teaching. In the staff-led group (SG), students were taught by a group of three ultrasound-experienced doctors. Exposure took place in two separate lessons (each of 120 minutes) and introduced eight standard sectional planes (EULAR) using a

Peer teaching: a randomised controlled trial using student-teachers to teach musculoskeletal

Purpose
Sacroiliac screw fixation is the method of choice for the definitive treatment of unstable posterior pelvic-ring injuries; however, this technique is demanding and associated with a high risk of iatrogenic neurovascular damage. This study evaluates whether minimally invasive transiliac locked compression plate stabilisation may be an alternative to sacroiliac screw fixation in unstable posterior pelvic-ring injuries.

/pdf/minimally-invasive-stabilisation-of-posterior-pelvic-ring-27symtujcs.pdf

Minimally invasive stabilisation of posterior pelvic-ring instabilities with a transiliac locked compression plate.

Sacroiliac screw fixation is the method of choice for the definitive treatment of unstable posterior pelvic ring injuries; however this technique is demanding and associated with a high risk of iatrogenic neurovascular damage. We therefore evaluated the outcome, complications, surgical and fluoroscopy time for unstable posterior pelvic ring injuries managed with a transiliac locked compression plate. 23 patients were managed with a transiliac locked compression plate for unstable posterior pelvic injuries at a Level I Trauma Center. 21 patients were available for follow up after an average of 30 months and outcome evaluation was performed with the Pelvic Outcome Score, which is composed of a clinical, radiological, and social integration part. The overall outcome for the pelvic outcome score was excellent in 47.6% (10 patients), good in 19% (4 patients), fair in 28.6% (6 patients) and poor in 4.8% (1 patient). 15 out of 21 patients (71.4%) returned to their normal life, 3 patients (14.3%) were limited at work, and 3 patients (14.3%) were not able to return to work due to their disabilities. The social status was unchanged to the preinjury status in 19 patients (90.5%). 13 patients (62%) stated no changes in spare time and sports activities; 4 patients (19%) had minor and another 4 patients (19%) had major restrictions. The average operation time was 101 min and intraoperative fluoroscopic time averaged 74.2 sec. No iatrogenic neurovascular injuries were observed. Posterior percutaneous plate osteosynthesis may be a good alternative to sacral screw fixation because it is quick, safe, and associated with a good functional outcome.

Richard Martin Sellei

Papers

Structural, mechanical and in vitro characterization of individually structured Ti-6Al-4V produced by direct laser forming.

Peer teaching: a randomised controlled trial using student‐teachers to teach musculoskeletal ultrasound

Peer teaching: a randomised controlled trial using student-teachers to teach musculoskeletal

Minimally invasive stabilisation of posterior pelvic-ring instabilities with a transiliac locked compression plate.

Minimally invasive stabilization of posterior pelvic ring instabilities with a transiliac locked compression plate.