Energy
Laser Scan Path Design for Controlled Microstructure in Additive Manufacturing with Integrated Reduced-Order Phase-Field Modeling and Deep Reinforcement Learning
Twumasi, Augustine, Roy, Prokash Chandra, Li, Zixun, Bhattacharjee, Soumya Shouvik, Gan, Zhengtao
Laser powder bed fusion (L-PBF) is a widely recognized additive manufacturing technology for producing intricate metal components with exceptional accuracy. A key challenge in L-PBF is the formation of complex microstructures affecting product quality. We propose a physics-guided, machine-learning approach to optimize scan paths for desired microstructure outcomes, such as equiaxed grains. We utilized a phase-field method (PFM) to model crystalline grain structure evolution. To reduce computational costs, we trained a surrogate machine learning model, a 3D U-Net convolutional neural network, using single-track phase-field simulations with various laser powers to predict crystalline grain orientations based on initial microstructure and thermal history. We investigated three scanning strategies across various hatch spacings within a square domain, achieving a two-orders-of-magnitude speedup using the surrogate model. To reduce trial and error in designing laser scan toolpaths, we used deep reinforcement learning (DRL) to generate optimized scan paths for target microstructure. Results from three cases demonstrate the DRL approach's effectiveness. We integrated the surrogate 3D U-Net model into our DRL environment to accelerate the reinforcement learning training process. The reward function minimizes both aspect ratio and grain volume of the predicted microstructure from the agent's scan path. The reinforcement learning algorithm was benchmarked against conventional zigzag approach for smaller and larger domains, showing machine learning methods' potential to enhance microstructure control and computational efficiency in L-PBF optimization.
Multi-task parallelism for robust pre-training of graph foundation models on multi-source, multi-fidelity atomistic modeling data
Pasini, Massimiliano Lupo, Choi, Jong Youl, Zhang, Pei, Mehta, Kshitij, Weaver, Rylie, Aji, Ashwin M., Schulz, Karl W., Polo, Jorda, Balaprakash, Prasanna
Graph foundation models using graph neural networks promise sustainable, efficient atomistic modeling. To tackle challenges of processing multi-source, multi-fidelity data during pre-training, recent studies employ multi-task learning, in which shared message passing layers initially process input atomistic structures regardless of source, then route them to multiple decoding heads that predict data-specific outputs. This approach stabilizes pre-training and enhances a model's transferability to unexplored chemical regions. Preliminary results on approximately four million structures are encouraging, yet questions remain about generaliz-ability to larger, more diverse datasets and scalability on supercomputers. We propose a multi-task parallelism method that distributes each head across computing resources with GPU acceleration. Implemented in the open-source HydraGNN architecture, our method was trained on over 24 million structures from five datasets and tested on the Perlmut-ter, Aurora, and Frontier supercomputers, demonstrating efficient scaling on all three highly heterogeneous super-computing architectures. Keywords: Graph Neural Networks Distributed Data Parallelism Model Parallelism Multi-Fidelity Data Atomistic Modeling.
Evaluating the Robustness of Dense Retrievers in Interdisciplinary Domains
Chaturvedi, Sarthak, Acharya, Anurag, Meyur, Rounak, Hayashi, Koby, Munikoti, Sai, Horawalavithana, Sameera
Evaluation benchmark characteristics may distort the true benefits of domain adaptation in retrieval models. This creates misleading assessments that influence deployment decisions in specialized domains. We show that two benchmarks with drastically different features such as topic diversity, boundary overlap, and semantic complexity can influence the perceived benefits of fine-tuning. Using environmental regulatory document retrieval as a case study, we fine-tune ColBERTv2 model on Environmental Impact Statements (EIS) from federal agencies. We evaluate these models across two benchmarks with different semantic structures. Our findings reveal that identical domain adaptation approaches show very different perceived benefits depending on evaluation methodology. On one benchmark, with clearly separated topic boundaries, domain adaptation shows small improvements (maximum 0.61% NDCG gain). However, on the other benchmark with overlapping semantic structures, the same models demonstrate large improvements (up to 2.22% NDCG gain), a 3.6-fold difference in the performance benefit. We compare these benchmarks through topic diversity metrics, finding that the higher-performing benchmark shows 11% higher average cosine distances between contexts and 23% lower silhouette scores, directly contributing to the observed performance difference. These results demonstrate that benchmark selection strongly determines assessments of retrieval system effectiveness in specialized domains. Evaluation frameworks with well-separated topics regularly underestimate domain adaptation benefits, while those with overlapping semantic boundaries reveal improvements that better reflect real-world regulatory document complexity. Our findings have important implications for developing and deploying AI systems for interdisciplinary domains that integrate multiple topics.
Gear News This Week: The Repairable Fairphone 6 Arrives and Samsung's Galaxy Unpacked Is Up Next
The sixth generation of Fairphone arrived this week, featuring a modular design built to last from ethically sourced components in a climate-conscious way. It has been a couple of years since its predecessor, the Fairphone 5, and the Fairphone 6 is refreshingly smaller and lighter. It boasts a 6.3-inch OLED screen with a 120-Hz adaptive refresh rate, a Qualcomm Snapdragon 7s Gen 3 processor, and a 4,415 mAh battery that Fairphone says is good for up to two days. You also get a 50-megapixel main camera with a 13-MP ultrawide lens and a 32-MP selfie camera. Fairphone says the new device is made with more than 50 percent fair and recycled materials, including cobalt sourced through the Fair Cobalt Alliance, fair gold, silver, and tungsten, and recycled aluminum and rare earth metals.
Google's emissions up 51% as AI electricity demand derails efforts to go green
Google's carbon emissions have soared by 51% since 2019 as artificial intelligence hampers the tech company's efforts to go green. While the corporation has invested in renewable energy and carbon removal technology, it has failed to curb its scope 3 emissions, which are those further down the supply chain, and are in large part influenced by a growth in datacentre capacity required to power artificial intelligence. The company reported a 27% increase in year-on-year electricity consumption as it struggles to decarbonise as quickly as its energy needs increase. Datacentres play a crucial role in training and operating the models that underpin AI models such as Google's Gemini and OpenAI's GPT-4, which powers the ChatGPT chatbot. The International Energy Agency estimates that datacentres' total electricity consumption could double from 2022 levels to 1,000TWh (terawatt hours) in 2026, approximately Japan's level of electricity demand.
Our favorite budget smart bird feeder is cheaper than it has been all year at Amazon
I put a bird feeder outside my window a few years ago and it was a fantastic decision. I can look out there and see a wide variety of feathered friends chowing down on the regionally appropriate bird food I provide for them. I also get to see squirrels acting foolish. Right now, Amazon has the Birdfy smart bird feeders on deep discount well before the Prime Day shopping holiday rolls around in early July. This is the easiest possible way to bird watch.
Inside a plan to use AI to amplify doubts about the dangers of pollutants
An industry-backed researcher who has forged a career sowing doubt about the dangers of pollutants is attempting to use artificial intelligence (AI) to amplify his perspective. Louis Anthony "Tony" Cox Jr, a Denver-based risk analyst and former Trump adviser who once reportedly claimed there is no proof that cleaning air saves lives, is developing an AI application to scan academic research for what he sees as the false conflation of correlation with causation. Cox has described the project as an attempt to weed "propaganda" out of epidemiological research and perform "critical thinking at scale" in emails to industry researchers, which were obtained via Freedom of Information Act requests by the Energy and Policy Institute, a non-profit advocacy group, and exclusively reviewed by the Guardian. He has long leveled accusations of flimsiness at research linking exposure to chemical compounds with health dangers, including on behalf of polluting interests such as cigarette manufacturer Philip Morris and the American Petroleum Institute โ a fossil fuel lobbying group he has even allowed to "copy edit" his findings. Both the tobacco and oil industries have a history of weaponizing scientific uncertainty, experts say, with some arguing that similar tactics drive the Trump administration's current deregulatory efforts. The president's May "gold standard" science order, for instance, empowered his appointees to "correct scientific information" and "discipline" those who breach the administration's views, prompting outrage from some scientists. Cox has obtained funding to develop the new AI reviewer from the American Chemistry Council (ACC), the nation's largest chemical industry advocacy group, which counts oil and chemical giants such as Exxon and DuPont as members.
Welcome: Sustainability and Computing Special Section
Environmental sustainability is a critical global imperative and existential challenge for humanity. While computing professionals tend to think of computing as a positive technology, there's no doubt it also has significant negative impacts, such as growing environmental damage. Firstly, computing is a rapidly growing consumer of environmental resources (for example, minerals, water), a producer of greenhouse-gas emissions (for example, operational, embodied), a creator of environmental pollution (for example, e-waste), and an enabler of environmentally harmful activities. This damage has grown steadily over decades with little prospect of slowing (see the recent Communications article by Eeckhout2). But secondly, computing has an important role in understanding climate change and reducing greenhouse gas emissions and other environmental damage in a broad array of societal activities (for example, agriculture, transportation, manufacturing, facility management, power generation, and more) and other applications that hope to promote environmental sustainability.
Trump's tax bill seeks to prevent AI regulations. Experts fear a heavy toll on the planet
US Republicans are pushing to pass a major spending bill that includes provisions to prevent states from enacting regulations on artificial intelligence. Such untamed growth in AI will take a heavy toll upon the world's dangerously overheating climate, experts have warned. About 1bn tons of planet-heating carbon dioxide are set to be emitted in the US just from AI over the next decade if no restraints are placed on the industry's enormous electricity consumption, according to estimates by researchers at Harvard University and provided to the Guardian. This 10-year timeframe, a period of time in which Republicans want a "pause" of state-level regulations upon AI, will see so much electricity use in data centers for AI purposes that the US will add more greenhouse gases to the atmosphere than Japan does annually, or three times the yearly total from the UK. The exact amount of emissions will depend on power plant efficiency and how much clean energy will be used in the coming years, but the blocking of regulations will also be a factor, said Gianluca Guidi, visiting scholar at the Harvard TH Chan School of Public Health.
This battery recycling company is now cleaning up AI data centers
The event marked the launch of the company's new business line, Redwood Energy, which will initially repurpose (rather than recycle) batteries with years of remaining life to create renewable-powered microgrids. Such small-scale energy systems can operate on or off the larger electricity grid, providing electricity for businesses or communities. Redwood Materials says many of the batteries it takes in for processing retain more than half their capacity. "We can extract a lot more value from that material by using it as an energy storage project before recycling it," JB Straubel, Redwood's founder and chief executive, said at the event. This first microgrid, housed at the company's facility in the Tahoe Reno Industrial Center, is powered by solar panels and capable of generating 64 megawatt-hours of electricity, making it one of the nation's largest such systems.