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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

LSA Large Area Silicon Sheet Task. Continuous Liquid Feed Czochralski Growth

The design and development of equipment and processes to demonstrate continuous growth of crystals by the Czochralski method suitable for producing single silicon crystals for use in solar cells is presented. The growth of at least 150 kg of mono silicon crystal, 150 mm in diameter is continuous from one growth container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a meltdown system with a continuous solid silicon feed mechanism and a liquid transfer system, with associated automatic feedback controls is discussed. Due to the silicon monoxide build up in the furnace and its retarding effect on crystal growth the furnace conversion for operation in the low pressure range is described. Development of systems for continuous solid recharging of the meltdown chamber for various forms of poly silicon is described.

Fiegl, G.↗
NASA NTRS1989

Continuous hydroponic wheat production using a recirculating system

Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

Mackowiak, C. L.↗
NASA NTRS1994

Continuous monitoring of bacterial attachment

A major concern with the Space Station Freedom (SSF) water supply system is the control of longterm microbial contamination and biofilm development in the water storage and distribution systems. These biofilms have the potential for harboring pathogens as well as microbial strains containing resistance factors that could negatively influence crew health. The proposed means for disinfecting the water system on SSF (iodine) may encourage the selection of resistant strains. In fact, biofilm bacteria were observed in water lines from the Space Shuttle Columbia (OV-102); therefore, an alternative remediation method is required to disinfect spacecraft water lines. A thorough understanding of colonization events and the physiological parameters that will influence bacteria adhesion is required. The limiting factor for development of this technology is the ability to continuously monitor adhesion events and the effects of biocides on sessile bacteria. Methods were developed to allow bacterial adhesion and subsequent biocidal treatment to be monitored continuously. This technique couples automated image analysis with a continuous flow of a bacterial suspension through an optical flow cell. A strain of Pseudomonas cepacia isolated from the water supply of the Space Shuttle Discovery (OV-103) during STS-39 was grown in a nitrogen-limited continuous culture. This culture was challenged continuously with iodine during growth, and the adhesion characteristics of this strain was measure with regard to flow rate. Various biocides (ozone, hypochlorite, and iodine) were added to the flow stream to evaluate how well each chemical removed the bacteria. After biocide treatment, a fresh bacterial suspension was introduced into the flow cell, and the attachment rate was evaluated on the previously treated surface. This secondary fouling was again treated with biocide to determine the efficacy of multiple batch chemical treatments in removing biofilm.

Koeing, D. W.↗
NASA NTRS1998

Diagnostic yield and optimal duration of continuous-loop event monitoring for the diagnosis of palpitations. A cost-effectiveness analysis

BACKGROUND: Continuous-loop event recorders are widely used for the evaluation of palpitations, but the optimal duration of monitoring is unknown. OBJECTIVE: To determine the yield, timing, and incremental cost-effectiveness of each week of event monitoring for palpitations. DESIGN: Prospective cohort study. PATIENTS: 105 consecutive outpatients referred for the placement of a continuous-loop event recorder for the evaluation of palpitations. MEASUREMENTS: Diagnostic yield, incremental cost, and cost-effectiveness for each week of monitoring. RESULTS: The diagnostic yield of continuous-loop event recorders was 1.04 diagnoses per patient in week 1, 0.15 diagnoses per patient in week 2, and 0.01 diagnoses per patient in week 3 and beyond. Over time, the cost-effectiveness ratio increased from $98 per new diagnosis in week 1 to $576 per new diagnosis in week 2 and $5832 per new diagnosis in week 3. CONCLUSIONS: In patients referred for evaluation of palpitations, the diagnostic yield of continuous-loop event recording decreases rapidly after 2 weeks of monitoring. A 2-week monitoring period is reasonably cost-effective for most patients and should be the standard period for continuous-loop event recording for the evaluation of palpitations.

NASA Discipline Cardiopulmonary↗
NASA NTRS2010

A Terminal Area Analysis of Continuous Ascent Departure Fuel Use at Dallas/Fort Worth International Airport

Aircraft departing from the Dallas/Fort Worth International Airport (DFW) encounter vertical restrictions that prevent continuous ascent operations. The result of these restrictions are temporary level-offs at 10,000 feet. A combination of flow direction, specific Area Navigation (RNAV) route geometry, and arrival streams have been found to be the biggest factors in the duration and frequency of a temporary level-offs. In total, 20% of DFW departures are affected by these level-offs, which have an average duration of just over 100 seconds. The use of continuous descent approaches at DFW are shown to lessen the impact arrivals have on the departures and allow more continuous ascents. The fuel used in a continuous ascent and an ascent with a temporary level-off have been calculated using a fuel burn rate model created from a combination of actual aircraft track data, aircraft manufacturer flight operations manuals, and Eurocontrol's Base of Aircraft Data (BADA) simulation tool. This model represents the average aggregate burn rates for the current fleet mix at DFW. Continuous ascents would save approximately seven gallons of fuel out of 450 gallons used to climb to a cruise altitude of 31,000ft per departure.

Roach, Keenan↗
NASA NTRS2012

Preliminary Design and Evaluation of an Airfoil with Continuous Trailing-Edge Flap

This paper presents the preliminary design and evaluation of an airfoil with active continuous trailing-edge flap (CTEF) as a potential rotorcraft active control device. The development of structural cross-section models of a continuous trailing-edge flap airfoil is described. The CTEF deformations with MFC actuation are predicted by NASTRAN and UM/VABS analyses. Good agreement is shown between the predictions from the two analyses. Approximately two degrees of CTEF deflection, defined as the rotation angle of the trailing edge, is achieved with the baseline MFC-PZT bender. The 2D aerodynamic characteristics of the continuous trailing-edge flap are evaluated using a CFD analysis. The aerodynamic efficiency of a continuous trailing-edge flap is compared to that of a conventional discrete trailing-edge flap (DTEF). It is found that the aerodynamic characteristics of a CTEF are equivalent to those of a conventional DTEF with the same deflection angle but with a smaller flap chord. A fluid structure interaction procedure is implemented to predict the deflection of the continuous trailingedge flap under aerodynamic pressure. The reductions in CTEF deflection are overall small when aerodynamic pressure is applied: 2.7% reduction is shown with a CTEF deflection angle of two degrees and at angle of attack of six degrees. In addition, newly developed MFC-PMN actuator is found to be a good supplement to MFC-PZT when applied as the bender outside layers. A mixed MFC-PZT and MFC-PMN bender generates 3% more CTEF deformation than an MFC-PZT only bender and 5% more than an MFC-PMN only bender under aerodynamic loads.

Shen, Jinwei↗
NASA NTRS2014

Exploratory Study for Continuous-time Parameter Estimation of Ankle Dynamics

Recently, a parallel pathway model to describe ankle dynamics was proposed. This model provides a relationship between ankle angle and net ankle torque as the sum of a linear and nonlinear contribution. A technique to identify parameters of this model in discrete-time has been developed. However, these parameters are a nonlinear combination of the continuous-time physiology, making insight into the underlying physiology impossible. The stable and accurate estimation of continuous-time parameters is critical for accurate disease modeling, clinical diagnosis, robotic control strategies, development of optimal exercise protocols for longterm space exploration, sports medicine, etc. This paper explores the development of a system identification technique to estimate the continuous-time parameters of ankle dynamics. The effectiveness of this approach is assessed via simulation of a continuous-time model of ankle dynamics with typical parameters found in clinical studies. The results show that although this technique improves estimates, it does not provide robust estimates of continuous-time parameters of ankle dynamics. Due to this we conclude that alternative modeling strategies and more advanced estimation techniques be considered for future work.

neuromuscular systems↗
NASA NTRS2018

Simulating the Effects of Carbon Nanotube Continuity and Interfacial Bonding on Composite Strength and Stiffness

Molecular dynamics simulations of carbon nanotube (CNT) composites, in which the CNTs are continuous across the periodic boundary, overestimate the experimentally measured mechanical properties of CNT composites along the fiber direction. Since the CNTs in these composites are much shorter than the composite dimensions, load must be transferred either directly between CNTs or through the matrix, a mechanism that is absent in simulations of effectively continuous CNTs. In this study, the elastic and fracture properties of high volume fraction discontinuous carbon nanotube/amorphous carbon composite systems were compared to those of otherwise equivalent continuous CNT composites using ReaxFF reactive molecular dynamics simulations. These simulations were used to show how the number of nanotube-matrix interfacial covalent bonds affect composite mechanical properties. Furthermore, the mechanical impact of interfacial bonding was decomposed to reveal its effect on the properties of the CNTs, the interfacial layer of matrix, and the bulk matrix. For the composites with continuous reinforcement, it was found that any degree of interfacial bonding has a negative impact on axial tensile strength and stiffness. This is due to disruption of the structure of the CNTs and interfacial matrix layer by the interfacial bonds. For the discontinuous composites, the modulus was maximized between 4%-7% interfacial bonding and the strength continues to increase up to the highest levels of interfacial bonding studied. Areas of low stress and voids were observed in the simulated discontinuous composites at the ends of the tubes, from which fracture was observed to initiate. Experimental carbon nanotube yarn composites were fabricated and tested. The results were used to illustrate knockdown factors relative to the mechanical performance of the tubes themselves.

Benjamin D Jensen↗
NASA NTRSDate not supplied

Comparison Between Continuous and Intermittent Actigraphy Outcomes During Long-Duration Missions

INTRODUCTION Historically, astronauts have worn actigraphy watches continuously throughout their missions. This has enabled reliable sleep estimation and comparisons between sleep and other outcomes and mission activities such as the arrival of a visiting vehicle. However in late 2020, astronauts were scheduled to wear an actiwatch for one 2-week period every two months, substantially decreasing availability of data. Our aim was to compare sleep and mission events between data collected continuously and data collected intermittently to identify any differences. METHODS Crewmembers (n = 19) who volunteered for the NASA Standard Measures protocol between January 2019 and March 2022 were provided with actiwatches (Phillips, Respironics, Bend OR) that they wore either continuously (C; n = 9) or for two weeks every two months while in space (2W; n = 10). We used crew schedules to identify mission events that were asynchronous with actigraphy. We further compared sleep outcomes (sleep duration, wake after sleep onset [WASO], sleep efficiency) between the C and 2W actigraphy collection. RESULTS In the 2W group, sleep data was not available for 52% of EVAs, 67% of visiting vehicle events, and 67% of commander turnovers. Average sleep duration for the 2W group (M = 6.91, ± 1.24 SD) was significantly lower compared to the C group (7.51 ± 1.08, p < .01). Sleep efficiency was better for those in the C group (90.56 ± 5.19) than for those in the 2W group (87.02 ± 6.47 p < .01). There were no significant differences in WASO (C = 26.66 ±12.99; 2W = 32.38 ± 18.83). DISCUSSION Continuous actigraphy data collection yields different sleep outcomes compared to intermittent data collection. In addition, many mission events were not captured with intermittent data collection. Our findings support the use of continuous actigraphy data collection.

fatigue↗
NASA NTRSDate not supplied

Validation of a Probabilistic Continuity Assessment Method for Earth Observation Portfolios

With the increased reliance on spaceborne Earth observation data among the Earth science community and other end users, it is important that efforts are made to promote data continuity for a range of parameters of interest. Continuity gaps may occur between missions measuring like parameters due to mission development delays or early termination and introduce the potential of increased uncertainty for retrieved parameters. To inform portfolio-level decisions for Earth observing missions, Ivanco et al. developed a method that enables the assessment of the probability of continuity gaps for multi-mission architectures and provides a framework to assess this probability in the context of multiple scenarios that represent possible future states of the architecture [Ivanco et al., “A Scenario-Based Approach to Assess Continuity Gaps in Earth Observations,” IEEE Aerospace Conf., 2024]. While this method was previously applied to assess continuity gaps for a specific multi-mission architecture, it had not yet been validated with historical data. This paper outlines the process of validating the probabilistic gap assessment method by utilizing data obtained from past NASA Earth Science mission formulation documents and provides a discussion of the results and takeaways from the validation. Future areas of improvement pertaining to both the modeling and simulation methodologies and underlying assumptions are identified and discussed.

Katharine Burn↗
DOE OSTI2025

A bilevel multistage stochastic self-scheduling model with indivisibilities for trading in the continuous intraday electricity market

In this paper, we study the profit maximization problem of a virtual power plant trading in the continuous intraday electricity market. Our virtual power plant model is compatible with renewable, and thermal assets, covering a range of virtual power plants currently participating in energy markets. We model the trading problem as a bilevel multistage stochastic program. The upper level of the problem accounts for the profit maximization of the virtual power plant with explicit modeling of the technical constraints of the operational status of the thermal power plant including minimum start-up and shut-down times, ramp-up and ramp-down rates, and minimum generation level. The upper level also decides which continuous and indivisible (fill-or-kill) orders are submitted to the market. The lower-level problem accounts for the clearing of the continuous intraday market, i.e., matching of buy and sell orders. Because of the presence of fill-or-kill orders, the lower-level problem is mixed-integer, which prevents its direct conversion to a single-level problem using duality. In order to solve this challenging problem, we develop a convex-hull extended formulation for the lower-level problem, apply duality theory to obtain a single-level stochastic equivalent formulation, and employ McCormick envelopes to turn the problem into a multistage stochastic mixed-integer linear problem, which we solve using the stochastic dual dynamic integer programming algorithm. We conduct numerical experiments and analyze the optimal trading behavior of a virtual power plant trading in an ideal continuous market without arbitrage.

Bilevel multistage stochastic programming problem↗
DOE OSTI2025

Outlook towards deployable continual learning for particle accelerators

Particle accelerators are high power complex machines. To ensure uninterrupted operation of these machines, thousands of pieces of equipment need to be synchronized, which requires addressing many challenges including design, optimization and control, anomaly detection and machine protection. With recent advancements, machine learning (ML) holds promise to assist in more advance prognostics, optimization, and control. While ML based solutions have been developed for several applications in particle accelerators, only few have reached deployment and even fewer to long term usage, due to particle accelerator data distribution drifts caused by changes in both measurable and non-measurable parameters. In this paper, we identify some of the key areas within particle accelerators where continual learning can allow maintenance of ML model performance with distribution drifts. Particularly, we first discuss existing applications of ML in particle accelerators, and their limitations due to distribution drift. Next, we review existing continual learning techniques and investigate their potential applications to address data distribution drifts in accelerators. By identifying the opportunities and challenges in applying continual learning, this paper seeks to open up the new field and inspire more research efforts towards deployable continual learning for particle accelerators.

43 PARTICLE ACCELERATORS↗
NASA NTRS2020

Continuity of MODIS and VIIRS Snow Cover Extent Data Products for Development of an Earth Science Data Record

An Earth Observing System global snow cover extent data products record at moderate spatial resolution (375–500 m) began in February 2000 with the Moderate-resolution Imaging Spectroradiometer (MODIS) instrument onboard the Terra satellite. The record continued with the Aqua MODIS in July 2002, the Suomi-National Polar Platform (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) in January 2012 and continues with the Joint Polar Satellite System-1 (JPSS-1) VIIRS, launched in November of 2017. The objective of this work is to develop a snow cover extent Earth Science Data Record (ESDR) using different satellites, sensors and algorithms. There are many issues to understand when data from different algorithms and sensors are used over a decade-scale time period to create a continuous dataset. Issues may also arise with sensor degradation and even differences in sensor band locations. In this paper we describe development of an ESDR derived from existing MODIS and VIIRS data products and demonstrate continuity among the products. The MODIS and VIIRS snow cover detection algorithms produce very similar daily snow cover maps, with 90–97% agreement in snow cover extent (SCE) in different landscapes. Differences in SCE between products ranged from 2–15% and are attributable to convolved factors of viewing geometry, pixel spread across a scan and time of observation. Compared at a common grid size of 1 km, there is a mean of 95% agreement in SCE and a difference range of 1–10% between the MODIS and VIIRS SCE maps. Mapping sensor observations to a coarser resolution grid reduces the effect of the factors convolved in the 500 m tile to tile comparisons. We conclude that the MODIS and VIIRS SCE data products are reliable constituents of a moderate-resolution ESDR.

snow cover extent↗
DOE OSTI2025

Toward Continuous, Oriented Covalent Organic Framework Membranes for Precise Molecular Separations

The goal of achieving energy-efficient, precise molecular separations has motivated interest in developing and employing porous crystalline frameworks as membrane materials. Covalent organic frameworks (COFs) are ordered crystalline matrices composed of covalently bonded organic monomers and are synthesized via reversible reticular chemistry. COFs possess high porosity, structural tunability, and chemical and thermal stability, making them ideally suited for emerging, high-value membrane separation processes, such as ion separations, organic solvent nanofiltration, and gas separations. Although a range of COF membranes have been fabricated and tested in the past decade, these membranes are primarily polycrystalline, weakly crystalline, and/or discontinuous, resulting in suboptimal performance. In this review, we identify the properties that make COFs well-suited as membrane materials, while critically outlining the shortcomings of existing disordered COF membranes. We then highlight the recent emergence of highly crystalline, continuous, oriented two-dimensional COF membranes as a promising path forward for highly selective molecular separations. These continuous, oriented COF membranes exhibit tunable one-dimensional nanochannels, allowing for ultrafast molecular transport and precise species selectivity, thereby expanding the set of separations that can be practically achieved with membrane systems. We discuss synthesis and modification techniques that result in continuous, oriented COF membranes and evaluate the performance of such membranes for a variety of molecular separations. We conclude by identifying ongoing challenges in the development of COF membranes and outlining the future of their applications in molecular separations, which will necessarily rely on advancements in the synthesis of continuous, oriented membranes.

COF modification↗
DOE OSTI2026

Concatenated dual displacement code for continuous-variable quantum error correction

The continuous-variable (CV) Gaussian no-go theorem fundamentally limits the suppression of Gaussian displacement errors using only Gaussian gates and states. Prior studies have employed Gottesman-Kitaev-Preskill (GKP) states as ancillary qumodes to suppress small Gaussian displacement errors. However, when the displacement magnitude becomes large, inevitable lattice-crossing errors arise beyond the correctable range of the GKP state. To address this issue, we concatenate the Gaussian-noise-suppression circuit with an outer analog Steane code that corrects such occasional lattice-crossing events as well as other abrupt displacement errors. Contrary to conventional concatenation, which primarily aims to reduce logical error rates, the Steane-GKP duality in encoding provides complementary protection against displacement errors at different scales: The inner GKP layer employs non-Gaussian resources to suppress continuous Gaussian noise and reduce residual variance, while the outer analog Steane code corrects discrete lattice-crossing events that exceed the GKP correctable range. It is precisely this separation of error-mitigation roles that enables CV error correction. In contrast to prior work on concatenating GKP and repetition codes to establish error correction for discrete qubit/qudit encoding, we provide correction in the continuous encoding space. Analytical studies show that, under infinite squeezing, the concatenated code suppresses the variance of Gaussian displacement errors acting on all qumodes by up to 50%, while enabling unbiased correction of lattice-crossing errors with a success probability determined by the ratio between the residual Gaussian error standard deviation and the lattice-crossing magnitude. Even with finite squeezing, the proposed architecture still provides Gaussian-error suppression and lattice-crossing correction. Moreover, the presence of the outer analog Steane code relaxes the squeezing requirement of the inner GKP states, indicating near-term experimental feasibility. This work establishes a viable route toward fault-tolerant continuous-variable quantum computation and provides insight into the design of concatenated CV error-correcting architectures.

quantum error correction↗
DOE OSTI2025

Advancing continuous enzymatic hydrolysis for improved biomass saccharification

Background: A deployable, continuous enzymatic hydrolysis (CEH) process can address cost and commercialization risks associated with second-generation (Gen2) biorefinery sugar/lignin/ethanol production while contributing to energy supply and security. Developments in commercial enzymatic hydrolysis formulations targeting Gen2 pretreated biomass such as deacetylated mechanically refined (DMR) biomass necessitate a reassessment of the existing hybrid simultaneous saccharification and fermentation (SSF) approach. Notably, the practice of "finishing hydrolysis" in SSF has become problematic with the introduction of oxidative enzymes, such as lytic polysaccharide monooxygenases (LPMOs), into commercial cellulase formulations as these require specific redox conditions and cofactor. Moreover, continuous SSF has not been demonstrated at commercial scale, limiting deployment and the associated economic benefits to farmers, producers, and support industries. Results: Continuous enzymatic hydrolysis (CEH) was demonstrated at bench scale to enable optimal saccharification performance of deacetylated mechanically refined (DMR) pretreated biomass. Diafiltration was demonstrated to retain pretreated biomass solids and enzymes for continuous reaction while removing solubilized product sugars in situ. A significant breakthrough afforded by the CEH process is its ability to achieve equivalent endpoint conversions with approximately 50% lower enzyme loading. Yields of glucose and xylose were increased ~ 15% and ~ 4%, respectively, over batch hydrolysis. Unlike SSF using yeast or Zymomonas, CEH allows precise optimization of pH, temperature, oxygen tension, LPMO mediator concentration, and removal of end-product inhibitors. Conclusions: Advanced CEH holds promise as a transformational, process-intensified, and cost-effective method for producing soluble clarified biomass sugars and insoluble lignin-rich streams. Enhancing saccharification performance, optimizing operating parameters, and employing membrane filtration will help overcome existing challenges and enable the efficient production of valuable biomaterials from lignocellulosic biomass.

09 BIOMASS FUELS↗
DOE OSTI2024

Continuous automatic polarization channel stabilization from heterodyne detection of coexisting dim reference signals

Quantum networking continues to encode information in polarization states due to ease and precision. The variable environmental polarization transformations induced by deployed fiber need correction for deployed quantum networking. Here, we present a method for automatic polarization compensation (APC) and demonstrate its performance on a metropolitan quantum network. Designing an APC involves many design decisions as indicated by the diversity of previous solutions in the literature. Our design leverages heterodyne detection of wavelength-multiplexed dim classical references for continuous high-bandwidth polarization measurements used by newly developed multi-axis (non-)linear control algorithm(s) for complete polarization channel stabilization with no downtime. This enables continuous relatively high-bandwidth correction without significant added noise from classical reference signals. We demonstrate the performance of our APC using a variety of classical and quantum characterizations. Finally, we use C-band and L-band APC versions to demonstrate continuous high-fidelity entanglement distribution on a metropolitan quantum network with an average relative fidelity of 0.94 ± 0.03 for over 30 hrs.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

A Novel Continuous Ultrasound-Assisted Leaching Process for Rare Earth Element Extraction: Environmental and Economic Assessment

Rare earth elements (REEs) make up integral components in personal electronics, healthcare instrumentation, and modern energy technologies. REE leaching with organic acids is an environmentally friendly alternative to traditional extraction methods. Our previous study demonstrated that batch ultrasound-assisted organic acid leaching of REEs can significantly decrease environmental impacts compared to traditional bioleaching. The batch method is limited to small volumes and is unsuitable for industrial implementation. This study proposes a novel approach to increase reaction volume using a continuous ultrasound-assisted organic acid leaching method. Laboratory experiments showed that continuous ultrasound-assisted leaching increased the leaching rate (µg/h) 11.3–24.5 times compared to our previously reported batch method. Techno-economic analysis estimates the cost of the continuous approach using commercially purchased organic acids is $\$$9465/kg of extracted REEs and $\$$4325/kg of extracted REEs, using gluconic acid and citric acid, respectively. The sensitivity analysis reveals that substituting commercially purchased organic acids with microbially produced biolixiviant can reduce the process cost by approximately 99% while minimally increasing energy consumption. Environmental assessment shows that most of the emissions stemmed from the energy required to power the ultrasound reactor. We concluded that increased leaching capacity using a continuous ultrasound-assisted approach is feasible, but process modifications are needed to reduce the environmental impact.

54 - ENVIRONMENTAL SCIENCES/GLOBAL CLIMATE CHANGE ↗