The elastic properties and electronic structure of PtN2 with the pyrite structure (PtN2(C2)) were studied with first-principles calculations. The crystal structure is demonstrated to be elastically stable with a lower energy than the metastable fluorite structure proposed before. The calculated shear modulus of 214 GPa suggests that PtN2(C2) is harder than some well known hard materials such as TiN and SiC. The high elastic moduli are attributed to a stacking of corner-shared PtN6 octahedra bonded by strong N-N covalent bonding. In contrast to the metallic fluorite-type phase, PtN2(C2) is semiconducting with an indirect band gap.

Aluminum-containing intergranular phases, forming intergranularfilms and secondary phase particles at triple-junctions in SiC hot-pressed with aluminum, boron, and carbon additions, were studied by transmission electron microscopy. Statistical high-resolution electron microscopy study of intergranular films indicated that a large fraction of the vitreous intergranular films in the s-hot-pressed SiC crystallized during postannealing in argon above 1000oC. However, brief heating to 1900oC indeed re-melted 25 percent of the crystallized intergranular films. The structural transitions were reflected in the statistical width distributions of the amorphous grain boundary layers. At triple-junctions, Al2O3, Al2OC-SiC solid solution, and mullite phases were newly identified. These phases,together with others reported before are represented in a quaternary phase diagram for 1900oC. It is proposed that a SiC-Al2OC liquid domain is to be included in this phase diagram.

Learning Objective: This review aims to provide a brief history of virtual simulation and how it is currently being applied as a clinical assessment tool in emergency medicine (EM) training.

Background: Simulation has played a vital role in training generations of medical professionals. In response to the COVID pandemic, virtual simulation (VS) has provided educational advantages to traditional in-person simulation. However, there is no current literature review on VS’s medical education application in the post-COVID pandemic setting.

Objective: This review aims to provide a brief history of VS and how it is currently being applied as a clinical assessment tool in emergency medicine (EM) training.

Method: We conducted an electronic database search of SCOPUS in November 2021 using the following terms: “virtual simulation,” “simulation history,” “virtual reality,” “online simulation,” “augmented reality,” “serious game,” “computer-based simulation,” “simulation,” “health care,” “emergency medicine,” “education,” and “assessment.” Returned articles were filtered based on the following: English language, their relevance/inclusion of a VS method, and EM learners as the population under investigation.

Results: 1,104 articles were identified, of which 19 addressed VS’s use in assessing EM education (1 article in the post-COVID setting). Historically, VS was used to assess emergency responders’ preparedness to major casualty events due to its ability to generate fictitious environments. In 2021, VS was deemed a feasible assessment tool of healthcare students’ clinical competency. More specifically, VS has been shown to be a feasible alternative to traditional oral examination for assessing both EM residents and pediatric EM resuscitation respectively.

Conclusion: VS has been shown to be as effective as traditional simulation methods in assessing EM learners. As the COVID pandemic continues, VS has and will continue to serve as an educational substitute to in-person simulation. We believe the use of VS will continue to grow as viable, standardized, and cost-effective means of assessing EM students’ knowledge and clinical competency.