SCI Engineered Materials (United States)

Abstract The ongoing advances in the manufacturing of composite materials have produced a paradigm shift in the realization of materials with complex microstructures for targeted applications, including composites with variable fiber diameters. To make the analysis of complex microstructure materials accessible to the materials/mechanics community involved in the design and fabrication of new generations of materials, an Application Programming Interface (API) was constructed that produces homogenized stress-strain response of composite materials under six fundamental unidirectional loadings. The API integrates two key computational components embedded in Python environment, namely: the Finite Volume Direct Averaging Micromechanics (FVDAM) homogenization theory coded in Matlab and connected through the Matlab-engine library, as well as Gravity Driven Microstructure Generation (GDMG) algorithm that generates complex composite microstructures. FVDAM provides more efficient solutions to problems with highly heterogeneous domains than the popular finite-element technique. The API may be used by researchers with little knowledge of the underpinning mechanics to study the effects of ordered/disordered fiber placement, fiber/matrix mechanical properties and content on the overall elastic-plastic response of unidirectional composites and their microstructure-property relationship. We employ this API to generate the response of Hashin-type architectures and study the convergence of both elastic moduli and elastic-plastic response to transversely isotropic behavior under different loading directions as a function of the number of different-diameter fibers at a fixed fiber volume fraction.

The category of directed graphs is isomorphic to a particular category whose objects are labeled undirected bipartite graphs and whose morphisms are undirected graph morphisms that respect the labeling. Based on this isomorphism, we begin by showing that the class of all directed graphs is a Graph Isomorphism Complete class. Afterwards, by extending this categorical framework to weighted prime graphs, we prove that the categories of multidirected graphs with and without self-loops are each isomorphic to a particular category of weighted prime graphs. Consequently, we prove that these classes of multidirected graphs are also Graph Isomorphism Complete.

<div class="section abstract"><div class="htmlview paragraph">Reducing the emitted noise from vehicles is a primary issue for automotive OEMs due to the constant evolution of the noise regulations. In the context of electric powertrains, virtual prototyping has proven to be a cost-efficient alternative to the build-test process, especially in early design stage and/or if optimization is targeted. Due to the multiphysics nature of the model, the full simulation chain involves multiple components, each having its own specific modelling attributes. The difficulty then resides in the parts assembly, solving issues like mesh-to-mesh projections, time to frequency-domain transformation, 2d-axisymmetric to 3d mapping, data formatting and management, unit and local coordinate systems… This paper presents an environment that allows for the prediction and analysis of the noise radiated by electric automotive powertrains. The stator-rotor electro-magnetic behavior is represented by time-dependent forces applied on stator teeth. Transfer functions from structural modes to acoustic pressure describe the vibro-acoustic behavior and ensure a fast synthesis of the radiated noise. It is demonstrated how and where harmonic and space order decompositions are introduced in the computational process to deliver efficient and powerful analysis means to drive design decisions. As such, the workflow operation does not require deep expertise neither in electro-magnetic nor vibro-acoustic simulation. The proposed workflow, implemented in the Actran acoustic simulation environment, is finally used to obtain and analyze results on a typical industrial electric powertrain model.</div></div>

Companies are increasingly focused on driving the adoption of nature-based solutions across their organizations. Yet, implementing nature-based solutions within existing regulatory frameworks poses a unique set of challenges. In this paper, we present three nature-based solution case studies from The Dow Chemical Company and The Nature Conservancy's nearly 10-year collaboration. In the first case study, we focus on the potential benefits of reforestation to support the state's air quality improvement efforts. Ultimately, federal and state authorities did not approve of the reforestation project. Following this early setback, the collaboration team developed a suite of science-based tools that could be used to better advocate for government approval for the implementation of nature-based solutions. In the second case study, we highlight how one of these tools, the Ecosystem Services Identification & Inventory Tool, was used to improve communications about the benefits of nature-based solutions with regulatory agencies. In this case, Dow ultimately received approval for the restoration of a wetland to remediate an existing ash pond. Finally, the third case study highlights how engaging the right expertise through collaboration between the private sector and conservationists can improve land management strategies. Overall, this paper emphasizes the importance of robust conservation science, tools and expertise, and thoughtful collaboration as necessary means of driving the adoption of nature-based solutions both within a company and by its regulating entities. Integr Environ Assess Manag 2022;18:74-81. © 2021 SETAC.

Background: Trans-gender population is considered at high risk for HIV infection due to multiple factors. AHF Peru works with trans-female population since 2013, and since 2017, has implemented a "friendly" external consultant for Transfemale patients at Arzobispo Loayza National Hospital (HNAL), with a high impact in the attention of the HIV Trans-Female population. Methods: A cross-sectional, retrospective and descriptive study, evaluates the impact of this intervention in the quality of the attention of the Trans female population in Peru. The work was executed through II phases of implementation: Phase I: Approach of the female trans population to the friendly service considering a trans female hostess , support with diagnosis and timely linkage to HIV positive through a trans linker, provision of hormones, ensuring a comprehensive health system to 100%. Phase II: The trans-female population of Phase I, replicated the intervention and expanded the population by adding the approach to the system, HNAL assumed 100% of the cost of the hormonal treatment. Results: Before the start of this project, only 06 Trans female person were attended in the HNAL in the period of one year. Since the start of the implementation of consultant, there was an increase of around 3000% (182) in the number of patients. 87 (48%) were detected as reactive to HIV. After 10 months of starting care at the "First Friendly Practice for Trans-Female People", the MoH made the purchase and delivery of hormones to the HNAL. Currently, the hormone treatment is guaranteed for free for all female transwomen. Conclusions: Adapting the offer of a differentiated and friendly practice for the trans-female population, identifying their needs and values their health priorities, generates confidence and approach of female Trans population to the health system.

Inhalable metal organic framework (MOF) aerosols have been developed via spray drying as a therapy for multi-drug resistant (MDR) tuberculosis (TB). The CuPOA2 (pyrazinoate acid) MOFs can be tailored to exhibit a respirable mass median aerodynamic diameter (MMAD) of 2.6 μm. This method is repeated to manufacture Gd0.1Cu0.9(POA)2 MOFs for inhalable theragnostics.

3-Hydroxy-2-methylbutyrate (3H2MB) has been identified as a minor component of polyhydroxyalkanoates (PHAs) synthesized by bacteria living in activated sludge.

A new class of thermal protection materials based on a novel organic silicone polymer system, referred to generically as SM8000, was investigated. The composite material undergoes “ceramitization” on exposure to elevated temperatures under solid rocket exhaust plumes. SM8000 converts in situ to an oxidative resistant ceramic material at elevated temperatures. The remaining char forms a tough, abrasion-resistant surface. This paper summarizes the four year research anddevelopment program in refining, testing, anddeveloping this class of silicone polymer matrix composites as thermal protection materials. Composite design, specifically resin and reinforcement selection, composite geometry, ablation testing method development, as well as both prepreg and laminate manufacturing scale-up issues, were considered as an integral part of this research program. Thermal performance of this new class of silicone-based matrix composites exceeds the performance of the conventional phenolic-based matrix composites. A silicone quartz composite and process were developed that could provide a high-quality, flat, uniformpanelmeasuring 2.44 by 1.22mby9.53mm.SM8000 offers one of the best alternative polymer systems to the phenolic system that has been in use for the last 40 years.