Building Platform Research Articles

BrainPy, a flexible, integrative, efficient, and extensible framework for general-purpose brain dynamics programming.

Elucidating the intricate neural mechanisms underlying brain functions requires integrative brain dynamics modeling. To facilitate this process, it is crucial to develop a general-purpose programming framework that allows users to freely define neural models across multiple scales, efficiently simulate, train, and analyze model dynamics, and conveniently incorporate new modeling approaches. In response to this need, we present BrainPy. BrainPy leverages the advanced just-in-time (JIT) compilation capabilities of JAX and XLA to provide a powerful infrastructure tailored for brain dynamics programming. It offers an integrated platform for building, simulating, training, and analyzing brain dynamics models. Models defined in BrainPy can be JIT compiled into binary instructions for various devices, including Central Processing Unit, Graphics Processing Unit, and Tensor Processing Unit, which ensures high-running performance comparable to native C or CUDA. Additionally, BrainPy features an extensible architecture that allows for easy expansion of new infrastructure, utilities, and machine-learning approaches. This flexibility enables researchers to incorporate cutting-edge techniques and adapt the framework to their specific needs.

Effect of Build Orientation and Heat Treatment on Erosion Behavior of Al10SiMg Fabricated Using Laser Powder Bed Fusion

Laser Powder Bed Fusion (LPBF) is a form of additive manufacturing that can directly make metal components and has begun to be employed in a variety of industrial situations. Moreover, the erosion characteristics of SLM-produced items have been documented relatively infrequently. In the current work, the erosion behavior of a heat-treated Al-Si-10% Mg alloy generated via laser powder bed fusion (LPBF) has been investigated. The samples were printed in three directions (horizontal (0o), vertical (90o), and inclined (45o) on the build platform using the Direct Metal Laser Sintering (DMLS) system (EOS M 290) machine. Al%Si-10%Mg samples were given treatment (T5, T6). Optical and scanning electron microscopes (SEM) were used to examine the microstructure under both printed and heat-treated conditions. Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) were used to investigate the alloy's elemental composition and compound production. The erosion test was executed in each of the three orientations, plus heat-treated samples and as-printed samples. The selected input parameters were impingement angle and flow velocity. The erosion rate was examined and contrasted across orientations for printed and heat-treated conditions to establish the best orientation. The post-eroded surface was analysed using SEM, EDS, and XRD to evaluate possible erosion processes. The key findings were: T5 heat-treated samples sustain well and have the least mass loss; Horizontal (0°) oriented samples undergo less erosion compared to other orientations; T6 heat-treated samples show maximum erosion on printed samples, and hence it is not recommended. T5 heat treatment is proven to be superior in providing high erosion resistance, followed by printed and T6 heat-treatment, respectively. The heat treatment effects are more significant than the orientation effects in determining the erosion resistance of the Al10SiMg alloy. The erosion mechanisms, such as ploughing, melting, and cratering, were identified.

Change in Mechanical Properties of Laser Powder Bed Fused AlSi7Mg Alloy during Long-Term Exposure at Warm Operating Temperatures.

Al-Si-Mg alloys are most commonly used to produce parts by laser powder bed fusion for several industrial applications. A lot of papers have already focused on the effects induced by conventional heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys, rather than on AlSi7Mg. Nobody has investigated thermal stability during long-term direct and artificial aging heat treatments of AlSi7Mg. This study investigates the changes in mechanical properties induced by long-term exposure (512 h) at 150 and 175 °C (the operating temperature of AlSi7Mg) after (i) the laser powder bed fusion process performed on a pre-heated build platform (150 °C), and (ii) heat treatments to the solution at 505 °C per 0.5 and 4 h. Thermal stability was evaluated through both Vickers microhardness measurements to obtain the aging profiles, and tensile tests to evaluate the mechanical properties in specific conditions. An optical microscope was used to investigate the microstructure. It was found that aging at 175 °C confers the same effects induced by a secondary aging heat treatment on as-built samples and, simultaneously, the worst effects on the solution heat treated AlSi7Mg alloy after long-term exposure. The AlSi7Mg DA at both 150 °C and 175 °C showed the same Vickers microhardness (~95 HV0.5), UTS (~300 MPa), and YS (~200 MPa) values for the longest exposure times because the fine and cellular α-Al matrix confers higher stiffness and strength despite the over-aged conditions. On the other hand, the coarsening effects that affected the precipitates during aging at 175 °C, as well as the formation of the precipitate-free zones along the grain boundaries, justified the highest detrimental effects induced on the SHTed samples.

Towards data driven quality monitoring: alignment and correlation of photodiode-based co-axial melt pool monitoring signals to part quality in laser powder bed fusion

Online quality control of advanced manufacturing processes often utilize process monitoring as a qualification method to reduce or eliminate time consuming and costly destructive and non-destructive tests. The need for process monitoring based qualification becomes more apparent with the advent of laser based additive manufacturing for complex geometries and lot-size-one production. However, the usability of the process monitoring solution heavily relies on the accuracy of the established alignment and assignment of process signals to specific part and defects herein. This research proposes a data fusion strategy for data pre-processing to structure and align multi-source sensor data for improving correlation accuracy in process monitoring. A laser powder bed fusion system equipped with a photodiode-based co-axial melt pool monitoring is used for the study. First, the monitoring system collects photon emission data from the melt pool using photodiodes with high frequency (>100 kHz) which are aligned spatially and temporally using position data (xy-coordinates) of the galvanometer scanner and the laser ON/OFF signals. Next, a clustering approach is used to assign each photodiode signal with the individual parts on the build platform. Finally, correlation between melt pool monitoring signals and part level porosity is studied using micro-computed X-ray tomography (μCT) from a build job containing parts produced under varying process conditions.

Governance by platforms: Configuration of the relationship between Party-government and society in China

Platforms have emerged as the dominant mode of communication in China, empowering individuals to express their opinions and question the authority and credibility of the ruling party. To illustrate the impact of platforms on Party-government relations and society in China, we analyze four representative Chinese platforms: the Sina Microblog matrix of @Yinchuan for Governing Online, Shenzhen Baoan Tong APP, Shanghai Baoshan Community Link platform, and the smart party building platform in Beihai City. Drawing on these case studies, we argue that platforms not only provide channels for party control and government transformation, but also contribute to social progress by shaping the relationship between the Party-government and society, thus reshaping Chinese governance.

Importance of surface roughness on the magnetic properties of additively manufactured FeSi thin walls

Thin-walled structures are being used in soft magnetic components manufactured by additive manufacturing to limit eddy current losses in AC machines. Fe-6.5wt %Si has been shown to be a promising material in such components, however most characterisation has taken place using thicker bulk material. Thermal conditions and microstructure have been shown to differ within thin-walled structures, hence magnetic properties may also differ. This study characterises the magnetic properties of thin-walled structures, showing that the 〈001〉 texture usually apparent in laser powder-bed fusion does not persist in thin-walled samples built at an angle to the build platform. Surface roughness (Sa) is shown to increase with build angle from 28 µm when perpendicular to the build platform, to 80 µm when parallel, causing a deterioration in magnetic properties such as susceptibility which is reduced by up to 25 %. Improvements in magnetic properties are demonstrated for samples with lower surface roughness due to improved laser parameters, with even larger improvements available when using polishing as a post-process finishing operation which was shown to improve susceptibility by over 10 %. This study enables the designers of soft magnetic components made by additive manufacturing, the freedom to design magnetic flux paths at any angle in the build chamber and gives surface roughness as a key parameter to improve magnetic properties.

Fatigue behaviour of additive manufactured Nb-48Ti alloy parts from powders produced by Plasma Atomization (PA) and Hydride-Dehydride (HDH) process

Fatigue behaviour of bcc Nb-48 wt%Ti (Ti-36at%Nb) alloy parts processed by Laser Powder Bed Fusion (L-PBF) using as raw material two different types of powders, spherical powder produced by Plasma Atomization (PA) and irregularly shaped powder produced by Hydride-Dehydride (HDH) process, are compared. Laser power and scanning speed were selected to obtain rods with porosity below 0.5 vol%. All rods were produced using the same scanning strategy (chessboard with shift). The building platforms were heat treated for stress relieving at 650 °C for two hours before removing the rods using wire electro-discharge machining. The heat-traded rods were machined to obtain specimens for rotate bending fatigue tests, and S-N curves were plotted. Fatigue behaviour for PA and HDH sets were similar but with higher dispersed results for the specimens produced from the HDH powder. The fracture was nucleated in porosities near the machined sample surface, mostly on lack-of-fusion type pores. The fatigue cracks propagated in a “zigzag” mode with peaks and valleys parallel to the L-PBF building direction (BD) in both sets. One of the analysed samples, produced from HDH powder and with a lower fatigue life than average, showed a significantly higher number of pores, indicating the existence of a laser process parameter yet to be controlled.

The VA Research Enterprise: A Platform for National Partnerships Toward Evidence Building and Scientific Innovation.

Within a year of the start of the COVID-19 pandemic, the US Department of Veterans Affairs (VA) was managing about 300 COVID-19-related research projects across roughly 100 facilities, which has since grown to more than 900 projects. This robust set of activities arose from an existing enterprise strategy and aimed at identifying needs for supporting the clinical care mission, more rapidly leveraging resources, and coordinating research across the VA. The VA's efforts to implement an enterprise strategy before March 2020 positioned its research community to dynamically partner with other federal agencies, academic institutions, and industry in addressing a national public health emergency. The VA research enterprise involves a broad range of functions, scientific and clinical leaders, and organizational resources to enhance the health and care of veterans and the nation. The scope of research activities enables it to support its priorities while also partnering with others who share in mutual commitments to veteran health. Moving toward being the nation's learning health care system, the VA's leadership support, staff, patient volunteers, and partners were key contributors to a national response to COVID-19. Swift action and consistent communication helped address the complexities of the pandemic and strengthened the VA's ability to prepare and mobilize for emergencies and other potential disease outbreaks. Documenting strategies and practices can enhance future opportunities aimed at addressing the most challenging health care needs while also focusing on the primary mission to serve veterans. The COVID-19 pandemic contributed to critical knowledge and lessons that enabled the VA to advance enterprise goals, particularly in the context of its health care system. Sharing these unique processes and experiences will inform current and future partnerships among research, clinical, and public health communities oriented to serve veterans and the nation through scientific innovation.

Improving surgical safety checklist utilisation at 23 public health facilities in Ethiopia: a collaborative quality improvement project

BackgroundIn 2009, the WHO introduced the surgical safety checklist (SSC) as one of the interventions for improving patient safety. The systematic use of structured checklists during surgery has been shown...

Study on the Effect of Preheating Temperatures on Melt Pool Stability in Inconel 718 Components Processed by Laser Powder Bed Fusion

Laser Powder Bed Fusion (L-PBF) is one of the most widespread, versatile, and promising metal Additive Manufacturing (AM) techniques. L-PBF allows for the manufacturing of geometrically complex parts with good surface characteristics. In this process, in order to minimize the heat loss in the first layers of printing, the building platform is preheated to a temperature ranging between 80 and 250 °C. This aspect turns out to be very critical, and further investigation is needed for situations where the part to be printed is only a few layers high, as is the case in sensor printing. This work aims to investigate the melt pool stability under a variation in the preheating temperatures. We investigate the distance from the building platform, considering the number of layers printed. This is where the melt pool reaches its stability in terms of depth and width. This aspect turns out to be of remarkable importance for ensuring the structural integrity of parts with a few layers of height that are processed through L-PBF, such as sensors, which are proliferating in different industries. Thus, two case studies were carried out on IN718 superalloys at 40 and 60 microns of layer thickness and a preheating temperature of 170 °C on the machine. The results obtained show that after 1.2 mm of distance from the building platform, the melt pool reached its stability in terms of width and depth dimensions and consequently for the melting regime.

Characterization of 3D metal printed cutting tool with transpiration cooling channels

This study characterizes the 3D-printed transpiration cooling (TC) channels in a single-point cutting tool to enhance lubrication and cooling at the cutting zones. Five different TC channels, namely two circular profiled channels (Designs 1-A & 1-B), two hexagonal profiled channel (Designs 2-A & 2-B), and one bio-inspired blood vessel (Designs 3), are designed inside a single-point turning tool and 3D printed using AISI-1.2709 in powder bed fusion (PBF). From the materials and mechanical characterisation, fine cellular microstructure and high hardness are achieved. X-ray microcomputed tomography (XRμCT) has been used as a non-destructive inspection strategy to analyse the built structures. The results of XRμCT showed that the TC channel built is highly orientation-dependent, steeper angles deviate highly, and nominal angles such as 0° and 90° (to the build platform) provide the best dimensional accuracy. The average dimensional deviations of the five designs are −35.8%, −19.42%, −19.45%, −15.85%, and −5.02%, respectively, from the as-designed. The best designs are circular free-form (Design 1-B), hexagonal free-form (Design 2-B), and bio-inspired blood vessel (Design 3), which have the least dimensional deviation and highest accuracy.

KAJIAN POLA SIRKULASI MANUSIA TERHADAP KENYAMANAN PENUMPANG KERETA REL LISTRIK PADA STASIUN TANAH TINGGI KOTA TANGERANG

Technological progress develops rapidly from time to time. Railways as a mode of transportation, especially mass transportation, cannot be separated from other modes of transportation used in the national transportation system which have their own characteristics and advantages of mass transportation. Train stations also need to further develop their potential and improve good human circulation patterns so that passengers feel comfortable. As a transit point, Tanah Tinggi Station is a class III/small train station which only has 2 railroad tracks located in Tanah Tinggi, Tangerang City. However, circulation at stations can be very ironic when public facilities at stations do not pay much attention to the use of circulation for users of rail services. The author sees many problems that arise related to human circulation for the comfort of Electric Rail Train passengers at Tanah Tinggi Station, Tangerang City. This study aims to provide an overview of human circulation patterns and spatial planning, especially at the Tanah Tinggi station, so as to obtain the concept of circulation patterns and good spatial planning to increase passenger comfort. On This research uses descriptive analysis methods carried out in 3 ways, namely, literature studies, conducting surveys of research objects, and conducting interviews with users and managers of the highland station. The research was conducted in 5 sections, (1) the main entrance of the building, (2) supporting building corridors, (3) counters, (4) ticketing areas, and (5) platforms. It can be said that the results of the analysis carried out were not good enough for passengers because they have not been able to meet the standards and eligibility according to the regulations so that the ease of circulation for pedestrians to move can be disrupted and uncomfortable.

Inclusive Environmental Decision-making in a Developing Nation: Insights from the Ogoni Remediation Project, Niger Delta, Nigeria

Greater involvement of women is globally believed to enhance environmental management outcomes. Despite being disproportionately affected by environmental degradation primarily caused by oil spills in the Niger Delta region of Nigeria, women in the region are often excluded in environmental decision-making processes. Women involved in farming and fishing face increased vulnerability to contaminated land, food insecurity and conflicts driven by environmental degradation. Using a mixed approach, women, lawmakers, policymakers, regulators, civil society organizations, environmental management practitioners, and government agents responsible for environmental remediation were engaged through interviews, focus group discussions and questionnaires to examine women’s inclusion in environmental decision-making and governance in the Ogoni contaminated land remediation project in the Niger Delta region of Nigeria. The results indicate that lack of trust and confidence in drivers of the environmental decision-making process could affect women’s participation and involvement in environmental management. Although cultural beliefs and practices impede the participation of women in the region, their actual participation does not independently translate into inclusion in environmental decision-making due to limited capacity, confidence and trust in the process. Creating platforms for capacity building, developing gender policy, adapting appropriate communication strategies, initiating women networks and strengthening social cohesion could enhance women involvement in environmental decision-making in regions with similar cultural context to the Niger Delta region.

Influence of Build Orientation on Surface Roughness and Fatigue Life of the Al2024-RAM2 Alloy Produced by Laser Powder Bed Fusion (L-PBF)

Additive manufacturing of high strength Al alloys brings problems with hot cracking during rapid solidification. One of the ways to solve this challenge is technology developed by the Elementum 3D company. The way consists of inoculation by ceramic nanoparticles using RAM technology. When applying the L-PBF method, a very fine equiaxed microstructure with exceptional properties and without cracks is created. This paper offers the results and discussion of the microstructure, surface roughness and fatigue life of the high-strength Al2024-RAM2 alloy made from a gas atomized powder with an additive of 2 wt.% ceramic nanoparticles on the base of Ti. The specimens for fatigue tests were produced in different orientations relative to the building platform and left in the as-built conditions with different surface quality (roughness). The specimens were T6 heat-treated. The treatment caused a coarsening of a part of the fine grains. After T6 heat treatment, the hardness increased significantly, which occurred by precipitation hardening. Fatigue tests of specimens with different build orientation were performed in plane bending and the experimentally determined fatigue life was discussed in terms of surface roughness and material microstructure.

Decentralized Platforms: Governance, Tokenomics, and ICO Design

Traditional two-sided platforms (e.g., Amazon, Uber) rely primarily on commission contracts to generate revenues and fuel growth, whereas their decentralized counterparts (e.g., Uniswap, Filecoin) often forego these in favor of token retention. What economics underpin this choice? We show that with properly designed initial coin offerings (ICOs), both mechanisms can independently alleviate market failures at the initial fundraising stage and incentivize long-term platform building. However, they achieve this in different ways. Although commission contracts often lead to higher profits for founders, token retention leads to higher service levels, benefiting the users and service providers. In essence, token retention surrenders a fraction of earnings to better align with the tenets of decentralized governance. Combining both mechanisms can add value, but only in relatively limited cases. These findings offer guidance and a possible rationale for why platforms may want to favor one mechanism over the other or use both.This paper was accepted by Will Cong, Special Section of Management Science: Blockchains and Crypto Economics.Funding: This work is funded by the Mack Institute at the Wharton School, University of Pennsylvania.Supplemental Material: The online appendix is available at https://doi.org/10.1287/mnsc.2021.02076 .

The Comparative Effectiveness andProvider-induced Demand Collaboration Project: A Pioneering Military-Civilian Academic Partnership to Build Health Services Research Capacity forthe Military Health System.

Like civilian health systems, the United States Military Health System (MHS) confronts challenges in achieving the aims of reducing cost, and improving quality, access, and safety, but historically has lacked coordinated health services research (HSR) capabilities that enabled knowledge translation and iterative learning from its wealth of data. A military-civilian academic partnership called the Comparative Effectiveness and Provider-Induced Demand Collaboration (EPIC), formed in 2011, demonstrated early proof-of-concept in using the MHS claims database for research focused on drivers of variation in health care. This existing partnership was reorganized in 2015 and its topics expanded to meet the need for HSR in support of emerging priorities and to develop current and HSR capacity within the MHS. A Donabedian framework of structure, process, and outcomes was applied to support the project, through a core of principal investigators, researchers, analysts, and administrators. Within this framework, new researchers and student trainees learn foundations of HSR while performing secondary analysis of claims data from the MHS Data Repository (MDR) focusing on Health and Readiness, Pediatrics, Policy, Surgery, Trauma, and Women's Health. Since 2015, the project has trained 25 faculty, staff, and providers; 51 students and residents; 21 research fellows across multiple disciplines; and as of 2022, produced 107 peer-reviewed publications and 130 conference presentations, across all five themes and six cores. Research results have been incorporated into Federal and professional policy guidelines. Major research areas include opioid usage and prescribing, value-based care, and racial disparities. EPIC researchers provide direct support to MHS leaders and enabling expertise to clinical providers. EPIC, through its Donabedian framework and utilization of the MHS Data Repository as a research tool, generates actionable findings and builds capacity for continued HSR across the MHS. Eight years after its reorganization in 2015, EPIC continues to provide a platform for capacity building and knowledge translation.

해시태그 커뮤니티와 공동체성(Sense of Community)의 담화적 구성

This article examines the discursive construction of a sense of community within hashtag communities on Twitter, using a case study of tweets containing the hashtag ‘#Kpop’. Hashtags enable users to form loosely connected communities with others who share the same interests, whilst establishing relevance to specific topics and enhancing the searchability of online content. By analysing tweets with the ‘#Kpop’ hashtag, this study investigates the formation of hashtag communities. K-pop fans have utilised Twitter as a primary platform for communication, affinity building, and active participation in a range of social, cultural, and political activities. Therefore, this article explores how ‘#Kpop’ integrates heterogeneous voices, ultimately forming a hashtag community. By doing so, this research aims to provide insights into hashtag communities and the dynamics of online discourse facilitated by the ‘#Kpop’ hashtag.

A layerwise monitoring methodology based on blue laser line profilometer for Material Extrusion processes

AbstractMaterial Extrusion (MEX) is an Additive Manufacturing technology widely used for the fabrication of polymeric, metallic and composite parts with clear advantages. In the last decades, the growing interest of such industries like aerospace, medical, automotive and R&D has driven technological improvements of MEX to make the technology more reliable and repeatable. Although, defects and geometric dimensional inaccuracies are still known to affect the process, limiting the applicability of MEX for the realization of functional parts. Recently, in-process monitoring methods have been implemented for a rapid detection of defects and process anomalies, activating, eventually, the control of the process. In this work, an innovative layerwise monitoring methodology based on a high-resolution blue laser line profilometer applied to a MEX process, was proposed. By analyzing the point clouds of each layer, with proper quality indexes, it was possible to compute the layer height deviation and to evaluate the surface quality in terms of occurrence of defects. In particular, the quality indexes presented in this work were representative of the layer height accuracy, the occurrence and distribution of defects on the layer surface and the stability of the process (respectively the so-called indexes were ADLH, RAD and the slope s). Different process conditions were generated by varying the raster angle and the sample location on the building platform.

Study of the Effect of L-PBF Technique Temporal Evolution on Microstructure, Surface Texture, and Fatigue Performance of Ti gr. 23 Alloy

Titanium alloys are widely used in various technological fields due to their excellent performance. Since the early stages of the 3D printing concept, these alloys have been intensively used as materials for these processes. In this work, the evolution of the performance of the 3D printing process has been studied by analysing the microstructure and the mechanical properties, fatigue and tensile, of the Ti gr. 23 alloy produced by two different models of Concept Laser M2 Cusing machines (an old model and a more recent one). The process parameters recommended by the manufacturer were adopted for each machine. Both microstructural and surface texture characterisations were carried out to better correlate the differences with the production process technique. For the same purpose, tensile tests and microhardness profiles were obtained, while the dynamic mechanical properties were evaluated by means of fatigue tests aimed at determining the fatigue limit of the material using a staircase approach. The mechanical tests were carried out on specimens with three different orientations with respect to the building platform, using two different SLM techniques. The fatigue behaviour was then analysed by evaluating the fracture surfaces and, in particular, the crack nucleation sites. By comparing the calculated fatigue values with the results of local fatigue calculations, an estimate of the residual stresses near the crack nucleation site was obtained. The results showed that the specimens produced on a newer machine had lower roughness (about 10%), slightly higher ductility, and a higher fatigue limit (10–20 MPa) compared to the specimens produced with the same material but on older equipment.

Influence of a vibrating build platform on the density and hardness of parts made by laser powder bed fusion of metals

Influence of a vibrating build platform on the density and hardness of parts made by laser powder bed fusion of metals