Calculation of Dynamic Loads Due to Random Vibration Environments in Rocket Engine Systems

An important part of rocket engine design is the calculation of random dynamic loads resulting from internal engine "self-induced" sources. These loads are random in nature and can greatly influence the weight of many engine components. Several methodologies for calculating random loads are discussed and then compared to test results using a dynamic testbed consisting of a 60K thrust engine. The engine was tested in a free-free condition with known random force inputs from shakers attached to three locations near the main noise sources on the engine. Accelerations and strains were measured at several critical locations on the engines and then compared to the analytical results using two different random response methodologies

Validation and Preliminary Results of the Parental Assessment of Children's External Genitalia Scale for Females (PACE-F) for Girls With Congenital Adrenal Hyperplasia

Objective To validate a parental assessment of children's external genitalia scale for females (PACE-F) for girls with congenital adrenal hyperplasia (CAH) by adapting the validated adult female genital self-image scale. Methods PACE-F was administered to parents of girls (Tanner 1, 2 months-12 years) with and without CAH. Final questions were determined by clinical relevance and psychometric properties (scores: 0-100). A reference range was established using 95% confidence interval among controls. Age-matched controls were compared to girls with CAH (1) <4 years old before and after female genital reconstruction surgery (FGRS), and (2) 4-12-year olds after FGRS. Nonparametric statistics were used. Results Participants included 56 parents of 41 girls with CAH (median 3.9 years old, 97.6% FGRS) and 139 parents of 130 girls without CAH. Face and content validity was established by families, experts, and factor analysis. Internal consistency was high (Cronbach's alpha: 0.83). Population reference score range was 66.7-100. Ten consecutive girls had pre- and post-FGRS PACE-F scores. All scores improved at 4 months after surgery and all preoperative scores were below reference range and lower than controls (P = .0001). All postoperative scores were within reference range, no different from controls (P = .18). Scores for girls with CAH after FGRS aged 4-12 years were no different from controls (100.0 vs 88.9, P = .77) and 90.0% were in reference range, as expected (P = .99). Conclusion We present a validated instrument for parental assessment of genital appearance in girls with CAH. We demonstrate improved parent-reported appearance after FGRS, with scores similar to age-matched controls

Cloud Computing for Research and Education Gets a Sweet Upgrade with CACAO

We introduce Cloud Automation and Continuous Analysis Orchestration (CACAO), an open source web platform designed to facilitate access and availability of cloud resources for education and research. By leveraging open source Infrastructure-as-Code (IaC) technologies such as Terraform and Ansible, CACAO empowers users to create customized cloud resources and complex software stacks through an intuitive web interface. CACAO integrates with CyVerse, another prominent open source cyberinfrastructure, and is a featured interface for Jetstream2, a public education and research cloud. CACAO effectively manages multi-cloud deployments in OpenStack and commercial service providers. In 2022 bioinformatics and machine learning workshops worldwide used CACAO during its alpha release. CACAO adheres to open science standards and the FAIR data principles, broadening access to cloud platforms and reducing the complexity of deploying the resources necessary for teaching advanced data informatics skills required in today's workforce. © 2023 Owner/Author.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Engine System Loads Analysis Compared to Hot-Fire Data

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper