Materials
A robotic leg inspired from an insect leg
Tran-Ngoc, P. Thanh, Lim, Leslie Ziqi, Gan, Jia Hui, Wang, Hong, Vo-Doan, T. Thang, Sato, Hirotaka
While most insect-inspired robots come with a simple tarsus such as a hemispherical foot tip, insect legs have complex tarsal structures and claws, which enable them to walk on complex terrain. Their sharp claws can smoothly attach and detach on plant surfaces by actuating a single muscle. Thus, installing insect-inspired tarsus on legged robots would improve their locomotion on complex terrain. This paper shows that the tendon-driven ball-socket structure provides the tarsus both flexibility and rigidity, which is necessary for the beetle to walk on a complex substrate such as a mesh surface. Disabling the tarsus' rigidity by removing the socket and elastic membrane of a tarsal joint, the claws could not attach to the mesh securely. Meanwhile, the beetle struggled to draw the claws out of the substrate when we turned the tarsus rigid by tubing. We then developed a cable-driven bio-inspired tarsus structure to validate the function of the tarsus as well as to show its potential application in the legged robot. With the tarsus, the robotic leg was able to attach and retract smoothly from the mesh substrate when performing a walking cycle.
GelBot – A new 3D printing method to tackle sustainability in soft robots
Future generations of robots will work very differently from those that assemble entire vehicles or solder electronics onto circuit boards at lightning speed on factory floors today. They will leave the factory halls and start working with people, handing them a tool at the right moment or assisting them in assembling heavy components. They will appear in agriculture, helping harvest the fields or process the fruits. And they will increasingly be found in living rooms, supporting and entertaining people there or simply making them feel less alone. Of course, these robots will also look different from the enormous metallic contraptions found in today's industrial plants.
Estimation of Standard Auction Models
Cherapanamjeri, Yeshwanth, Daskalakis, Constantinos, Ilyas, Andrew, Zampetakis, Manolis
Estimating value and/or bid distributions from an observed sequence of auctions is a fundamental challenge in Econometrics with direct practical applic ations. For example, these fundamentals allow one to analyze the performance of an auction and make co unterfactual predictions about alternatives. The difficulty of this problem depends on the fo rmat of the auctions and the structure of the observed information from each one, as well as how the fundamentals of bidders are interrelated and vary across the sequence of observations. In this paper, we study a basic version of the afore-describe d estimation challenge, wherein the auction format and the bidder distributions stay fixed across observations, and the bidders have independent private values (which are independently resam pled across different observations). The auction formats that we consider are first-and second-pri ce auctions, as well as Dutch and English auctions. What will make our problem challenging is that (i) our bidders are ex ante asymmetric, drawing their independent private values from different distributions; (ii) we will make no parametric assumptions about these distributions; and (iii) we will only be observing the 1 identity of the winner and the price they paid but not the losi ng bids. Under this observational model and our independent private values assumption above, we can focus our attention on first-and second-price auctions, and our results automatically e xtend to Dutch and English auctions. In the above settings, we give computationally and sample ef ficient methods for estimating all agents' bid distributions and (under equilibrium assumpti ons) value distributions: In the case of first-price auctions, we provide finite-sample es timation guarantees under L evy, Kolmogorov and T otal V ariation distance with minimal assumptions. Under (a condition weaker than) a lower bound on the density of the bid dis tributions (although we actually do not need existence of densities), Theorem 2.2 shows that the bid distributions can be estimated to within ε in L evy distance, using 1/ ε
AI helps scientists design novel plastic-eating enzyme
In brief A synthetic enzyme designed using machine-learning software can break down waste plastics in 24 hours, according to research published in Nature. Scientists at the University of Texas Austin studied the natural structure of PETase, an enzyme known to degrade polymer chains in polyethylene. Next, they trained a model to generate mutations of the enzyme that work fast at low temperatures, let the software loose, and picked from the output a variant they named FAST-PETase to synthesize. FAST stands for functional, active, stable, and tolerant. FAST-PETase, we're told, can break down plastic in as little as 24 hours at temperatures between 30 and 50 degrees Celsius.
Plastic waste could be a thing of the past thanks to new PET-eating enzyme
Plastic waste dumped in landfill could be cleared sooner than expected, after engineers developed an enzyme that can break it down in just a few hours. Millions of tons of plastic is left abandoned every year, pilling up in landfills and pollution the land and waterways - typically taking centuries to degrade. A team from the University of Texas in Austin created a new enzyme variant that can supercharge recycling on a large scale, reducing the impact of plastic pollution. The work focusing on PET (polyethylene terephthalate), which is a polymer found in most consumer plastic including bottles, packaging and some textiles. The enzyme was able to complete a'circular process' of breaking down the plastic into smaller parts and chemically putting it back together in as little as 24 hours. They've called it FAST-PETase (functional, active, stable, and tolerant PETase), developed from a natural PETase that allows bacteria to degrade and modify plastic.
Spectroscopy and Chemometrics/Machine-Learning News Weekly #17, 2022
LINK "Feasibility of Near-Infrared Spectroscopy for Rapid Detection of Available Nitrogen in Vermiculite Substrates in Desert Facility Agriculture" LINK "Establishment of a Nondestructive Analysis Method for Lignan Content in Sesame using Near Infrared Reflectance Spectroscopy" LINK "Near Infrared Spectroscopy: A useful technique for inline monitoring of the enzyme catalyzed biosynthesis of third-generation biodiesel from waste cooking oil" LINK "A Study on Nitrogen Concentration Detection Model of Rubber Leaf Based on Spatial-Spectral Information with NIR Hyperspectral Data" LINK "Design and Performance of a Near-Infrared Spectroscopy Measurement System for In-Field Alfalfa Moisture Measurement" LINK "Estimating Forest Soil Properties for Humus Assessment--Is Vis-NIR the Way to Go?" LINK "Association and solubility of chlorophenols in CCl4: MIR/NIR spectroscopic and DFT study" LINK "Prediction of rhodinol content in Java citronella oil using NIR spectroscopy in the initial stage ...
Using artificial intelligence, Meta can build its data centers with low-carbon concrete - Actu IA
In 2018, Meta committed to minimizing its environmental footprint and is targeting net zero emissions for its value chain in 2030. However, it has plans to build eight data centers. To reduce the carbon emissions this one will generate, META's team, with the help of Lav Varshney and Nishant Garg from the University of Urbana-Champaign, designed a low-carbon concrete using generative machine learning algorithms that they tested at the Delkab, Illinois, facility. Concrete has been used for thousands of years to construct buildings and structures. Although it has evolved, cement is now one of its ingredients, but it is also the major source of its greenhouse gas emissions.
Self-driving tractors plowing ahead in the marketplace
Next time you pass a farm where a modern tractor is cruising around a field, take a closer look. While there is a farmer sitting in the cab, the vehicle might be driving itself. That tractor is often operating on auto pilot using semi-autonomous, self-driving technology. While the tractor plows along thanks to features like autosteer and computer-assisted technologies for applying fertilizers or pesticides, the farmer can send work texts or emails, pay bills or even flip through Instagram stories or TikTok videos. For farmers, this kind of efficiency is not a luxury.
Thermodynamically Consistent Machine-Learned Internal State Variable Approach for Data-Driven Modeling of Path-Dependent Materials
He, Xiaolong, Chen, Jiun-Shyan
Characterization and modeling of path-dependent behaviors of complex materials by phenomenological models remains challenging due to difficulties in formulating mathematical expressions and internal state variables (ISVs) governing path-dependent behaviors. Data-driven machine learning models, such as deep neural networks and recurrent neural networks (RNNs), have become viable alternatives. However, pure black-box data-driven models mapping inputs to outputs without considering the underlying physics suffer from unstable and inaccurate generalization performance. This study proposes a machine-learned physics-informed data-driven constitutive modeling approach for path-dependent materials based on the measurable material states. The proposed data-driven constitutive model is designed with the consideration of universal thermodynamics principles, where the ISVs essential to the material path-dependency are inferred automatically from the hidden state of RNNs. The RNN describing the evolution of the data-driven machine-learned ISVs follows the thermodynamics second law. To enhance the robustness and accuracy of RNN models, stochasticity is introduced to model training. The effects of the number of RNN history steps, the internal state dimension, the model complexity, and the strain increment on model performances have been investigated. The effectiveness of the proposed method is evaluated by modeling soil material behaviors under cyclic shear loading using experimental stress-strain data.
Machine learning-aided engineering of hydrolases for PET depolymerization - Nature
Plastic waste poses an ecological challenge1–3 and enzymatic degradation offers one, potentially green and scalable, route for polyesters waste recycling4. Poly(ethylene terephthalate) (PET) accounts for 12% of global solid waste5, and a circular carbon economy for PET is theoretically attainable through rapid enzymatic depolymerization followed by repolymerization or conversion/valorization into other products6–10. Application of PET hydrolases, however, has been hampered by their lack of robustness to pH and temperature ranges, slow reaction rates and inability to directly use untreated postconsumer plastics11. Here, we use a structure-based, machine learning algorithm to engineer a robust and active PET hydrolase. Our mutant and scaffold combination (FAST-PETase: functional, active, stable and tolerant PETase) contains five mutations compared to wild-type PETase (N233K/R224Q/S121E from prediction and D186H/R280A from scaffold) and shows superior PET-hydrolytic activity relative to both wild-type and engineered alternatives12 between 30 and 50 °C and a range of pH levels. We demonstrate that untreated, postconsumer-PET from 51 different thermoformed products can all be almost completely degraded by FAST-PETase in 1 week. FAST-PETase can also depolymerize untreated, amorphous portions of a commercial water bottle and an entire thermally pretreated water bottle at 50 ºC. Finally, we demonstrate a closed-loop PET recycling process by using FAST-PETase and resynthesizing PET from the recovered monomers. Collectively, our results demonstrate a viable route for enzymatic plastic recycling at the industrial scale. Untreated, postconsumer-PET from 51 different thermoformed products can all be almost completely degraded by FAST-PETase in 1 week and PET can be resynthesized from the recovered monomers, demonstrating recycling at the industrial scale.