RoboDepth: Robust Out-of-Distribution Depth Estimation under Corruptions

Depth estimation from monocular images is pivotal for real-world visual perception systems. While current learning-based depth estimation models train and test on meticulously curated data, they often overlook out-of-distribution (OoD) situations. Yet, in practical settings -- especially safety-critical ones like autonomous driving -- common corruptions can arise. Addressing this oversight, we introduce a comprehensive robustness test suite, RoboDepth, encompassing 18 corruptions spanning three categories: i) weather and lighting conditions; ii) sensor failures and movement; and iii) data processing anomalies. We subsequently benchmark 42 depth estimation models across indoor and outdoor scenes to assess their resilience to these corruptions. Our findings underscore that, in the absence of a dedicated robustness evaluation framework, many leading depth estimation models may be susceptible to typical corruptions. We delve into design considerations for crafting more robust depth estimation models, touching upon pre-training, augmentation, modality, model capacity, and learning paradigms. We anticipate our benchmark will establish a foundational platform for advancing robust OoD depth estimation.Comment: NeurIPS 2023; 45 pages, 25 figures, 13 tables; Code at https://github.com/ldkong1205/RoboDept

Leaching behaviors of impurities in metallurgical-grade silicon with hafnium addition

Hf was employed as an impurity getter to enhance the removal of impurities from metallurgical-grade Si (MG-Si) via the solidification of Si or a Si-33 wt% Al solvent. The leaching behaviors of the impurities (B, Fe, Al, Ca, P, Zr, Ti, V, Mn, Hf, and Ni) within MG-Si, in the presence of 5 wt% Hf, were investigated using various leaching approaches. Compared with aqua regia and HF, HCl + HF was determined to be the optimal lixiviant for the elimination of impurities from Hf-containing MG-Si. The use of a combination of HCl + HF and aqua regia reduced the quantity of impurities from 6126 ppmw to 94 ppmw. Eh-pH diagrams were calculated to discuss the leaching of HfSi2 in aqua regia and HF solutions. The presence of Hf in the MG-Si enhanced the removal of impurities, especially P, which cannot be efficiently removed via solidification refining and hydrometallurgical treatments. Hf-containing Si-Al solvent refining is considered the most efficient approach for the elimination of impurities (except Al). The removal fractions of B and P were 94.2% and 86.2%, respectively, achieved via the solidification of the Si-33 wt% Al solvent. Moreover, 99.94% and 99.9996% of the Hf, used as an impurity getter, could be eliminated through the solidification of the Si and Si-33wt% Al solvent, respectively, decreasing from 50,000 ppmw, to 28 ppmw and 0.2 ppmw, respectively

An Improved Energy Management Strategy for Hybrid Energy Storage System in Light Rail Vehicles

A single-objective optimization energy management strategy (EMS) for an onboard hybrid energy storage system (HESS) for light rail (LR) vehicles is proposed. The HESS uses batteries and supercapacitors (SCs). The main objective of the proposed optimization is to reduce the battery and SC losses while maintaining the SC state of charge (SOC) within specific limits based on the distance between consecutive LR stations. To do this, a series of optimized SOC limits is used to prevent the SC from becoming exhausted prematurely instead of the standard SC SOC penalty term in the cost function. Meanwhile, a rule-based EMS (RB-EMS) is used to give the SCs charging priority over the batteries when the vehicle is braking. Moreover, a simplified method for the optimization is proposed to reduce the computational burden. Simulation and experimental results for the proposed EMS and a standard SC SOC penalty-based cost function optimization are provided to evaluate losses. As a result, it is shown that the proposed EMS, compared with standard SC SOC penalty-based cost function optimization, decreases losses and prevents the SOC from reach the discharging limits

Application of a pH Feedback-Controlled Substrate Feeding Method in Lactic Acid Production

Substrate concentration in lactic acid fermentation broth could not be controlled well by traditional feeding methods, including constant, intermittent, and exponential feeding methods, in fed-batch experiments. A simple feedback feeding method based on pH was proposed to control pH and substrate concentration synchronously to enhance lactic acid production in fed-batch culture. As the linear relationship between the consumption amounts of alkali and that of substrate was concluded during lactic acid fermentation, the alkali and substrate in the feeding broth were mixed together proportionally. Thus, the concentration of substrate could be controlled through the adjustment of pH automatically. In the fed-batch lactic acid fermentation with Lactobacillus lactis-11 by this method, the residual glucose concentration in fermentation broth was controlled between 4.1 and 4.9 g L-1, and the highest concentration of lactic acid, maximum cell dry weight, volumetric productivity of lactic acid, and yield were 96.3 g L-1, 4.7 g L-1, 1.9 g L-1 h(-1) and 0.99 g lactic acid per gram of glucose, respectively, compared to 82.7 g L-1, 3.31 g L-1 1.7 g L-1 h(-1) and 0.92 g lactic acid per gram of glucose in batch culture. This feeding method was simple and easily operated and could be feasible for industrial lactic acid production in the future

J. Chem. Technol. Biotechnol.

BACKGROUND: The large output of monosodium glutamate in China has produced huge amounts of isoelectric supernatant containing 40-60 g L(-1) (NH(4))(2) SO(4). With the increasing national emphasis on environmental protection and recycling, it is necessary to find a cost-effective and environment-friendly alternative to recover the (NH(4))(2)SO(4). This paper reports on investigations of the electrodialysis process for (NH(4))(2)SO(4) recovery from isoelectric supernatant pretreated by ceramic membrane. RESULTS: For ceramic membrane pretreatment, the optimal pore size chosen was 0.2 mu m. After a 250 min run, permeate flux was still maintained at 90 L m(-2) h(-1) (v = 2.8 m s(-1), Delta TMP = 0.12 MPa, concentration factor = 7). Meanwhile, the total solids and proteins content in condensed supernatant were high, up to 78 g L(-1) and 24 g L(-1), respectively, which greatly favors future cell protein harvest. With the chosen current density of 17 mA cm(-2), the energy consumption and time for six consecutive batches for electrodialysis were 2.6-2.7 kW h kg(-1) sulfate and similar to 100 min, based on similar to 80% ammonium sulfate recovery from pretreated isoelectric supernatant. CONCLUSION: Ceramic membrane pretreatment was shown to be a promising pretreatment strategy, applicable to the electrodialysis process to recover ammonium sulfate from isoelectric supernatant produced during monosodium glutamate production. (C) 2008 Society of Chemical Industry.BACKGROUND: The large output of monosodium glutamate in China has produced huge amounts of isoelectric supernatant containing 40-60 g L(-1) (NH(4))(2) SO(4). With the increasing national emphasis on environmental protection and recycling, it is necessary to find a cost-effective and environment-friendly alternative to recover the (NH(4))(2)SO(4). This paper reports on investigations of the electrodialysis process for (NH(4))(2)SO(4) recovery from isoelectric supernatant pretreated by ceramic membrane

Optimization of an Energy Storage System for Electric Bus Fast-Charging Station

To relieve the peak operating power of the electric grid for an electric bus fast-charging station, this paper proposes to install a stationary energy storage system and introduces an optimization problem for obtaining the optimal sizes of an energy buffer. The charging power demands of the fast-charging station are uncertain due to arrival time of the electric bus and returned state of charge of the onboard energy storage system can be affected by actual traffic conditions, ambient temperature and other factors. The introduced optimization is formulated as a stochastic program, where the power matching equality of the total charging demands of connected electric buses is described as a chance constraint by denoting a satisfaction probability, then a stochastic supremum for the operating power of the electric grid is defined by actual data and the problem finally can be solved by convex programming. A case study for an existing electric bus fast-charging station in Beijing, China was utilized to verify the optimization method. The result shows that the operation capacity cost and electricity cost of the electric grid can be decreased significantly by installing a 325 kWh energy storage system in the case of a 99% satisfaction probability

The effect of ion exchange membranes on the bipolar membrane electrodialysis of ammonium chloride wastewater

Abstract The different bipolar membranes and their configurations with monopolar ion exchange membranes from different manufacturers such as FAB-FBM-FKB, AHA-(BP-1E)- CMB, and JAM-(BMP-1)-JCM are used in the bipolar membrane electrodialysis (BMED) of simulated NH4Cl wastewater to examine the effect of membrane properties on the generation of HCl and NH3?H2O. The results indicated that the configuration of AHA-(BP-1E)-CMB presented the promising performance among all the ion exchange membranes according to the generated acid and base concentration. And the configuration of FAB-FBM-FKB presented the expected performance on the membrane stack voltage, energy consumption, current efficiency of the BMED system. The stability of different ion exchange membranes in strong acid and base solution were investigated further by the analyses of SEM, contact angle and membrane resistance. It was found that the membranes AHA and FKB had better chemical stability than other membranes

Bioprocess. Biosyst. Eng.

One simple but efficient carbon-supplying device was designed and developed, and the correlative carbon-supplying technology was described. The absorbing characterization of this device was studied. The carbon-supplying system proved to be economical for large-scale cultivation of Spirulina sp. in an outdoor raceway pond, and the gaseous carbon dioxide absorptivity was enhanced above 78%, which could reduce the production cost greatly.One simple but efficient carbon-supplying device was designed and developed, and the correlative carbon-supplying technology was described. The absorbing characterization of this device was studied. The carbon-supplying system proved to be economical for large-scale cultivation of Spirulina sp. in an outdoor raceway pond, and the gaseous carbon dioxide absorptivity was enhanced above 78%, which could reduce the production cost greatly

Comparison of Fe~(2+) oxidation by Acidithiobacillus ferrooxidans in rotating-drum and stirred-tank reactors

Fe~(2+) oxidation by Acidithiobacillus ferrooxidans (At. ferrooxidans) under different solid contents by adding inert Al_2O_3 powder was examined in rotating-drum and stirred-tank reactors. The results show that the bioactivity of At. ferrooxidans in the stirred-tank is higher than that in the rotating-drum in the absence of Al_2O_3 powder, but the biooxidation rate of Fe~(2+) decreases markedly from 0.23 g/(L·h) to 0.025 g/(L·h) with increasing the content of Al_2O_3 powder from 0 to 50% (mass fraction) in the stirred- tank probably due to the deactivation of At. ferrooxidans resulting from the collision and friction of solid particles. The increase in Al_2O_3 content has a little adverse effect on the bioactivity of At. ferrooxidans in the rotating-drum due to different mixing mechanisms of the two reactors. The biooxidation rate of Fe~(2+) in the rotating-drum is higher than that in the stirred-tank at the same content of Al_2O_3 powder, especially at high solid content. The higher bioactivity of At. ferrooxidans can be maintained for allowing high solid content in the rotating-drum reactor, but its application potential still needs to be verified further by the sulfide bioleaching for the property differences of Al_2O_3 powder and sulfide minerals

Arsenopyrite bioleaching by Acidithiobacillus ferrooxidans in a rotating-drum reactor

A rotating-drum reactor with a gas-sparger of microfiltration ceramic membrane was used for arsenopyrite bioleaching by Acidithiobacillus ferrooxidans. The gas mass transport performance could be improved by adjusting the aeration rate and drum rotation speed, and high bioactivity of bacterial strains could be maintained at high pulp densities. Arsenopyrite bioleaching showed that higher pulp density could be allowed in the rotating-drum reactor, which was favorable to the reactor used in the bioleaching of sulfide minerals. (C) 2012 Elsevier Ltd. All rights reserved