Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Batch processing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Investigating the Potential for Recovering REEs from Coal Fly Ash and Power Plant Wastewater with an Engineered Sorbent

The global demand for rare earth elements (REE) has increased significantly in the past 20 years due to their extensive use in electronics and other applications. Although many recent studies related to quantifying rare earth elements in coal and coal combustion byproducts have been published, methods of extracting rare earth elements are still not economically feasible. The objective of our study is to investigate the potential extraction of the REEs from coal ash and from wastewater sludge collected from a power plant near Detroit, MI. The collected ash and sludge will undergo a hydrothermal extraction process developed by Los Alamos National Laboratory to extract REEs from the sludge or coal ash, resulting in a liquid enriched in dissolved REEs. Batch experiments were conducted using an organosilica adsorbent (Osorb) and a ligand [P-di(2-ethylhexyl) methanediphosphonic acid (DIPEX)] to extract neodymium from a synthetic hydrothermal extraction solution. DIPEX-associated Osorb media was produced by first dissolving DIPEX into a solvent (e.g., methanol). Different amounts of DIPEX-methanol solution were then added to 0.2 g of Osorb to determine the maximum sorption capacity. The methanol was evaporated and, after a rinse step, the DIPEX-Osorb sorbent was used in sorption experiments. A 300 ppm neodymium (Nd) synthetic ash/sludge leachate was tested with the various DIPEX-Osorb media. Results show that DIPEX-Osorb ratios of 4.3, 1.1, 0.5, and 0.05 mL/g sorbed 60, 51, 25, and 7 mg Nd per g media, respectively. Since the 4.3 mL DIPEX/g Osorb media sorbed 100% of the Nd in the solution, a higher capacity is expected and these experiments are ongoing. Breakthrough curve for of the sorption of Nd to Osorb was conducted and showed a higher sorption ratio when the Nd concentration increased. We are also investigating the reusability of the DIPEX-Osorb media by measuring how many cycles the media can be regenerated by extracting the Nd with nitric acid and reusing the sorbent for another cycle.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

Spark-plasma-sintering magnetic field assisted compaction of Co{sub 80}Ni{sub 20} nanowires for anisotropic ferromagnetic bulk materials

We developed a two-step process showing the way for sintering anisotropic nanostructured bulk ferromagnetic materials. A new reactor has been optimized allowing the synthesis of several grams per batch of nanopowders via a polyol soft chemistry route. The feasibility of the scale-up has been successfully demonstrated for Co{sub 80}Ni{sub 20} nanowires and a massic yield of ∼97% was obtained. The thus obtained nanowires show an average diameter of ∼6 nm and a length of ∼270 nm. A new bottom-up strategy allowed us to compact the powder into a bulk nanostructured system. We used a spark-plasma-sintering technique under uniaxial compression and low temperature assisted by a permanent magnetic field of 1 T. A macroscopic pellet of partially aligned nanowire arrays has been easily obtained. This showed optimized coercive properties along the direction of the magnetic field applied during compaction (i.e., the nanowires' direction)

36 MATERIALS SCIENCE↗
DOE OSTI2023

Enabling Entrained-Flow Gasification of Blends of Coal, Biomass and Plastics (Final Report)

This project demonstrated the technical feasibility of gasifying blends of coal, biomass and mixed waste plastics in a high pressure entrained-flow gasifier for production of hydrogen. This was achieved by creating slurries of coal, biomass pyrolysis liquids and liquefied plastic oil. Specific objectives of the project included (1) determining compositions of coal-biomass-plastic mixtures that produce a stable slurry suitable for pumping to high pressure, (2) designing and testing a novel burner to effectively atomize the mixed feedstock slurry in a pressurized gasifier, and (3) acquiring first-of-a-kind performance data for pressurized, oxygen-blown entrained-flow gasification of slurried blends of coal, biomass and plastic. A key focus of the project was preparation of mixtures of coal, biomass and plastic. To facilitate easy pumping to high pressure, slurries were created using (i) bioliquid resulting from a well-established rapid thermal treatment pyrolysis process, (ii) oil produced from waste plastic via an available thermal conversion process, and (iii) ground coal. Lab-scale tests were conducted to evaluate viscosity and stability/propensity for the mixtures to separate over time. Larger batches of the most promising slurry compositions were prepared and subjected to pumping studies. It was found that mixtures containing less than about 40% coal and less than about 30% plastic oil were stable and of low enough viscosity to facilitate pumping to high pressure. A high-performance hot oxygen burner (HOB) was designed and fabricated for use in an existing 1 ton/day pressurized entrained-flow gasifier. Ex-situ testing demonstrated that the HOB provides excellent atomization of the slurries and creates a very uniform and robust flame. Performance of the HOB in the gasifier was exceptional and resulted in better conversion to syngas than any previous generation of burner. Fabricating the HOB for this project was challenging due to the relatively small scale of the gasifier. Performance in larger-scale systems is expected to be even better. Gasification of mixtures of coal, bioliquid and plastic oil proved to be relatively easy. The gasifier was able to be started up, pressurized and transitioned to the blended slurry feedstock with no technical difficulty. Syngas rich in CO and H 2 , with relatively low concentrations of CO 2 , was produced. During startup and at low gasification temperatures, soot formation was observed, as is typical for gasification of petroleum-based feedstocks. No slag buildup was observed under the conditions tested. The project was successful in demonstrating the technical feasibility of the concept. Future development should broaden the range of feedstocks under consideration, more deeply explore performance of the gasifier, and evaluate scale-up and implementation strategies.

08 HYDROGEN↗
DOE OSTI2018

GoldenEye: stream-based network packet inspection using GPUs

High-performance packet analysis systems have attracted great interest as tools to deal with security concerns in high-speed networks. Recently, researchers have utilized GPUs to improve packet processing performance. However, most existing work has been targeted at per-packet analysis level. Flow-centric operations have been challenging for GPUs because they require sequential operations and large buffers for flow reassembly. In this work, we present the GoldenEye GPU Packet Processing System (GoldenEye), a deep packet inspection (DPI) system that tracks out-of-order TCP packets and provides streambased signature matching. When a batch of packets arrives, GoldenEye sorts packets into flow-reassembled streams and normalizes retransmission through a GPU-implemented reordering module. For signatures that straddle batch boundaries, GoldenEye couples a small set of metadata with a functionallyequivalent minimal regular expression retrieval algorithm to connect the partial matches. Results show that GoldenEye can reassemble tens of millions of packets/sec and conduct stateful DPI operations on TCP streams at multi-ten Gbit/sec rates.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Radio Frequency Calcination of Gypsum for Sustainable Wallboard Production

This presentation details several accomplishments in the dielectric calcination of gypsum to stucco. 1) Verification that gypsum can be calcined via RF heating, 2)Characterization of heating and mass loss curve for a nucleation propagation reaction under electromagnetics 3) Full parametric studies examining effect of free moisture on heating and calcination, and 4) Finite element model of process with high predictive capability. Overall, Industrial implementation could save up to 63% energy, 50% water, and reduce carbon emissions by 63% based on batch scale studies.

Tjards, Jacob↗
DOE OSTI2015

Preliminary Analysis of Species Partitioning in the DWPF Melter

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas entrainment rates from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The only case considered in this study involved the SB6 pour stream sample taken while Canister #3472 was being filled over a 20-hour period on 12/20/2010, approximately three months after the bubblers were installed. The analytical results for that pour stream sample provided the necessary glass composition data for the mass balance calculations. To estimate the “matching” feed composition, which is not necessarily the same as that of the Melter Feed Tank (MFT) batch being fed at the time of pour stream sampling, a mixing model was developed involving three preceding MFT batches as well as the one being fed at that time based on the assumption of perfect mixing in the glass pool but with an induction period to account for the process delays involved in the calcination/fusion step in the cold cap and the melter turnover.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Metabolic characterization of anaerobic fungi provides a path forward for bioprocessing of crude lignocellulose

The conversion of lignocellulose-rich biomass to bio-based chemicals and higher order fuels remains a grand challenge, as single-microbe approaches often cannot drive both deconstruction and chemical production steps. In contrast, consortia based bioprocessing leverages the strengths of different microbes to distribute metabolic loads and achieve process synergy, product diversity, and bolster yields. Here, we describe a biphasic fermentation scheme that combines the lignocellulolytic action of anaerobic fungi isolated from large herbivores with domesticated microbes for bioproduction. When grown in batch culture, anaerobic fungi release excess sugars from both cellulose and crude biomass due to a wealth of highly expressed carbohydrate active enzymes (CAZymes), converting as much as 49% of cellulose to free glucose. This sugar-rich hydrolysate readily supports growth of Saccharomyces cerevisiae, which can be engineered to produce a range of value-added chemicals. Further, construction of metabolic pathways from transcriptomic data reveals that anaerobic fungi do not catabolize all sugars that their enzymes hydrolyze from biomass, leaving other carbohydrates such as galactose, arabinose, and mannose available as nutritional links to other microbes in their consortium. Although basal expression of CAZymes in anaerobic fungi is high, it is drastically amplified by cellobiose breakout products encountered during biomass hydrolysis. Overall, these results suggest that anaerobic fungi provide a nutritional benefit to the rumen microbiome, which can be harnessed to design synthetic microbial communities that compartmentalize biomass degradation and bioproduct formation.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2019

Enzymatic synthesis of 1-caffeoylglycerol with deep eutectic solvent under continuous microflow conditions

1-caffeoylglycerol (1-CG) is a hydrophilic ester with a high solubility, and has a strong activity to prevent skin cancer caused by ultraviolet. However, the current preparation process to synthesize 1-CG via transesterification from methyl caffeate (MC) and glycerin was not economic due to long reaction time or adding extra field. Therefore, an enzymatic synthesis with deep eutectic solvent chloride-urea (ChCl-urea) in a microreactor was firstly applied under continuous microflow condition to improve the productivity. A maximum 1-CG yield of 96.49% was obtained under the optimized conditions: temperature of 65 degrees C, flow rate of 2 $μ$L/min, MC concentration of 50 g/L. Compared to the batch reactor, the reaction time reduced by 75%, the $K_m$ value decreased by 5/6, the reuse times of lipase increased by 2.29-fold, the external mass and transfer coefficients increased 10 times, which process was verified by numerical simulation. In addition, the produced 1-CG of 2 mg/mL has a high UV damage remediation ability of 75.16% using HaCaT cell model, which reveals 1-CG can repair the damage of cells radiated by the UV. Thus, this approach represents a convenient and cost-saving method to produce 1-CG using microfuidic biocatalysis.

09 BIOMASS FUELS↗
DOE OSTI2012

Preliminary ILAW Formulation Algorithm Description (Rev. 1)

The U.S. Department of Energy (DOE), Office of River Protection (ORP), has contracted with Bechtel National, Inc. (BNI) to design, construct, and commission the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site (DOE 2000). This plant is designed to operate for 40 years and treat roughly 50 million gallons of mixed hazardous high-level waste (HLW) stored in 177 underground tanks at the Hanford Site. The process involves separating the high-level and low-activity waste (LAW) fractions through filtration, leaching, Cs ion exchange, and precipitation. Each fraction will be separately vitrified into borosilicate waste glass. This report documents the initial algorithm for use by Hanford WTP in batching LAW and glass-forming chemicals (GFCs) in the LAW melter feed preparation vessel (MFPV). Algorithm inputs include the chemical analyses of the pretreated LAW in the concentrate receipt vessel (CRV), the volume of the MFPV heel, and the compositions of individual GFCs. In addition to these inputs, uncertainties in the LAW composition and processing parameters are included in the algorithm.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Geometric Analysis Based Double Closed-loop Iterative Learning Control of Output PDF Shaping of Fiber Length Distribution in Refining Process

In order to improve the pulp quality and to reduce the energy consumption, the fiber length distribution (FLD) is generally employed as one of the important technological indexes in the refining process. Considering that the traditional mean and variance of fiber length are unable to adequately characterize the non-Gaussian distribution properties, this paper proposes a novel geometric analysis based double closed-loop iterative learning control (ILC) method for probability density function (PDF) shaping of output FLD in the refining process. Primarily, a RBF neural network (NN) with Gaussian-type is utilized to approximate the square root PDF in the inner loop, where the RBF basis function parameters (center and width) are tuned between any two adjacent batches by using an ILC law, and the subspace identification method can be applied to establish the state-space model of weight vector. Then, for the sake of accelerating the convergence rate of the closed-loop sysyem, a geometric analysis based ILC method is adopted in the outer loop. Lastly, both simulation and experiments demonstrate the effectiveness and practicability of the proposed approach.

42 ENGINEERING↗
DOE OSTI2020

Production of levulinic acid and biocarbon electrode material from corn stover through an integrated biorefinery process

To overcome the inefficient biomass conversion, waste generation, and lack of co-production in biorefineries, an integrated process was proposed for the conversion of corn stover into levulinic acid and biocarbon electrode material. Corn stover was pretreated through hydrothermal process using 0.45 wt% K 2 CO 3 which removed 76 wt% lignin and 85 wt% xylan while preserving 83 wt% glucan. This was followed by acid hydrolysis to produce levulinic acid at varying H 2 SO 4 concentrations and reaction time in a batch reactor at 190 °C. At a reaction time of 5 min in 2 wt% H 2 SO 4 , 35.8 wt% and 30 wt% glucan in raw and pretreated corn stover was converted to levulinic acid, respectively. The residue from acid hydrolysis was converted into biocarbon for supercapacitor electrodes via a two-step thermal activation process which showed a specific capacitance of 120 F g -1 . The proposed integrated biorefinery concept provides multiple value-added products for a greater financial and environmental sustainability.

09 BIOMASS FUELS↗
DOE OSTI2015

Oxidation and Extraction of Americium(VI) from Lanthanides

Partitioning and transmutation of americium and curium has been the subject of significant research in the nuclear fuel cycle over the past two decades. Numerous approaches have been studied to separate these elements from the lanthanide elements to enable their recycle and transmutation. Americium is one of the primary long-term heat sources in used nuclear fuel, which may impact repository loading. The lanthanides are both a) neutron poisons, reducing reactor performance, if recycled, and b) can chemically interact with fuel cladding to cause early failure, if present in sufficient concentration. Chemical separation approaches for heterogeneous fuel recycle, typically utilize proven technology (PUREX or modifications to the PUREX process) to remove uranium and plutonium from the dissolved fuel (and if desired, can remove neptunium as well). Follow-on processing is then required to separate the americium and curium, or the americium alone (for target fabrication). In a homogeneous recycle approach, the bulk of the uranium is typically separated first, followed by additional processing to remove the transuranic elements as a group. Because of the chemical similarity of the americium with the lanthanides, and particularly with curium, these separate processes are difficult. Utilizing the unique valence states of americium (primarily the (VI) oxidation state), opens up new opportunities for the separation of americium for either heterogeneous recycle (enabling americium separation alone) or homogeneous recycle (separating americium together with plutonium and neptunium). The US Department of Energy Fuel Cycle Technologies program has been researching methods to oxidize americium and to extract it from lanthanides as americium(VI), preferably from molar nitric acid solutions. Early efforts identified sodium bismuthate as an effective oxidant, which enabled testing of the extraction of americium(VI) by tributyl phosphate and diamylamylphosphonate. Successful extraction of americium(VI) was demonstrated in this system, in both batch contact laboratory tests and in centrifugal contactors; however, the sodium bismuthate is a solid, and must be in excess of saturation with the solution. This creates some engineering challenges in the process. A significant effort to identify alternative oxidants has led to a number of promising approaches. Silver-catalyzed ozone, copper(III) periodate, and electrochemical oxidation of americium from the trivalent to hexavalent state have all been successfully demonstrated in laboratory experiments. These approaches would enable oxidation and extraction of americium without having to filter solids. Once the americium is oxidized, a key issue is how long it will remain in the hexavalent state. Investigations have shown that some materials of construction (e.g., tantalum) do not reduce americium as quickly as stainless steel. Also, alternative extractants, such as amides, do not appear to reduce the americium as rapidly as the phosphate or phosphonate extractants. While still early in their development, these advances in the technology offer some positive indications that a workable extraction process for the separation of americium(VI) can be realized in the near future.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Melt Processing Pretreatment Effects on Enzymatic Depolymerization of Poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) is a common thermoplastic material, used in a wide variety of applications (i.e., bottles, fabrics, packaging, electronics, and automotive components). Increasing demand for PET has precipitated a need for improved recycling technology, especially for single-use PET waste. Recently, enzymatic depolymerization has shown promise as an environmentally responsible alternative for PET chemical recycling that yields economically useful products (e.g., terephthalic acid, adipic acid, and ethylene glycol). However, the depolymerization system still suffers from low rates on crystalline PET substrates, and effects of realistic waste streams are not known. In our work, PET waste is pretreated using an ultra-high-speed twin-screw extruder system. PET substrates were modified by various processing pretreatments to allow enzymes better access to depolymerize substrate materials. The effect of varying throughput and mechanical shear on structural properties of the PET waste was analyzed using molecular weight and thermal characterizations. These pretreated samples exhibit modifications in molecular weight, glass transition temperature, crystallinity, and specific surface area. The unpurified leaf-branch compost cutinase enzyme produced from the fed-batch fermentation of Escherichia coli BL21(DE3) was used in enzymatic depolymerization, where a faster reaction was observed as crystallinity was decreased and the specific surface area was increased. The rate of terephthalic acid production was also significantly higher for samples processed at lower mechanical shear with higher throughputs. As a result, this work demonstrates the potential for tailoring pretreatments in pursuit of faster and more energy efficient PET recycling using enzymes, with facile adaptation to the industrial scale for the circular economy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Properties of na‐montmorillonite and cellulose nanocrystal reinforced poly(butyl acrylate‐co‐methyl methacrylate) nanocomposites

Poly(butyl acrylate‐co‐methyl methacrylate) (BA‐co‐MMA) nanocomposite latexes were synthesized in the presence of sodium montmorillonite (Na‐MMT) and cellulose nanocrystal (CNC) as fillers. Nanocomposite preparation with 3 wt% Na‐MMT based upon the total monomer amount was conducted by semi‐batch emulsion polymerization. Furthermore, direct blending of neat copolymer latex with Na‐MMT was performed for comparison. CNC/BA‐co‐MMA nanocomposites were obtained via blending process with varying CNC content (1, 2, and 3 wt %). Good dispersion of both Na‐MMT and CNC within the copolymer matrix was achieved as demonstrated by X‐ray diffraction and transmission electron microscope. Particle size of the nanocomposite latexes was around 120 nm. Thermal, mechanical, and barrier properties of the copolymer showed great improvement with the addition of both Na‐MMT and CNC. CNC nanocomposites displayed enhanced properties with increasing CNC level. Tensile strength of copolymer latex with 3 wt% CNC reached 262.5% of the pristine latex, while tensile strength of Na‐MMT nanocomposite at the same content was 187.5% of the pristine latex. POLYM. ENG. SCI., 55:2922–2928, 2015. © 2015 Society of Plastics Engineers

Vatansever, Alican↗
DOE OSTI2019

Batch Adsorption and Column Transport Studies of 2,4,6-Trinitrotoluene in Chinese Loess

In present study, batch and column tests were conducted to investigate the kinetic and thermodynamic characteristics of the adsorption and transport of 2,4,6-trinitrotoluene (TNT) in Chinese loess with specific focus on the role of inherent colloid particles. Batch tests showed that a lot of TNT was absorbed in suspended colloid particles, and its adsorption reached equilibrium after about 10 h, the adsorption process can be best-fit by the pseudo-second order kinetic and Freundlich model. The adsorption was spontaneous, endothermic process, implying the adsorbed TNT is likely to release from soil matrix. These portend that the adsorbed TNT has a potential to co-transport with inherent colloid particles in loess. The column tests identified the potential, and showed TNT transport had obvious retardation effect, which may be ascribed to the release and transport of inherent colloidal particles as a key carrier. These findings are helpful to evaluate the loess interception and antifouling performance.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Enhanced hydrolysis and methane yield by applying microaeration pretreatment to the anaerobic co-digestion of brown water and food waste

Highlights: ► Microaeration pretreatment was effective for brown water and food waste mixture. ► The added oxygen was consumed fully by facultative microorganisms. ► Enhanced solubilization, acidification and breakdown of SCFAs to acetate. ► Microaeration pretreatment improved methane yield by 10–21%. ► Nature of inoculum influenced the effects of microaeration. - Abstract: Microaeration has been used conventionally for the desulphurization of biogas, and recently it was shown to be an alternative pretreatment to enhance hydrolysis of the anaerobic digestion (AD) process. Previous studies on microaeration pretreatment were limited to the study of substrates with complex organic matter, while little has been reported on its effect on substrates with higher biodegradability such as brown water and food waste. Due to the lack of consistent microaeration intensities, previous studies were not comparable and thus inconclusive in proving the effectiveness of microaeration to the overall AD process. In this study, the role of microaeration pretreatment in the anaerobic co-digestion of brown water and food waste was evaluated in batch-tests. After a 4-day pretreatment with 37.5 mL-O{sub 2}/L{sub R}-d added to the liquid phase of the reactor, the methane production of substrates were monitored in anaerobic conditions over the next 40 days. The added oxygen was consumed fully by facultative microorganisms and a reducing environment for organic matter degradation was maintained. Other than higher COD solubilization, microaeration pretreatment led to greater VFA accumulation and the conversion of other short chain fatty acids to acetate. This could be due to enhanced activities of hydrolytic and acidogenic bacteria and the degradation of slowly biodegradable compounds under microaerobic conditions. This study also found that the nature of inoculum influenced the effects of microaeration as a 21% and 10% increase in methane yield was observed when pretreatment was applied to inoculated substrates, and substrates without inoculum, respectively.

09 BIOMASS FUELS↗
DOE OSTI2013

Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film

Purpose: This paper presents EBT2 film verification of fractionated treatment planning with the Gamma Knife (GK) extend system, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery.Methods: A human head shaped phantom simulated the verification process for fractionated Gamma Knife treatment. Phantom preparation for Extend Frame based treatment planning involved creating a dental impression, fitting the phantom to the frame system, and acquiring a stereotactic computed tomography (CT) scan. A CT scan (Siemens, Emotion 6) of the phantom was obtained with following parameters: Tube voltage—110 kV, tube current—280 mA, pixel size—0.5 × 0.5 and 1 mm slice thickness. A treatment plan with two 8 mm collimator shots and three sectors blocking in each shot was made. Dose prescription of 4 Gy at 100% was delivered for the first fraction out of the two fractions planned. Gafchromic EBT2 film (ISP Wayne, NJ) was used as 2D verification dosimeter in this process. Films were cut and placed inside the film insert of the phantom for treatment dose delivery. Meanwhile a set of films from the same batch were exposed from 0 to 12 Gy doses for calibration purposes. An EPSON (Expression 10000 XL) scanner was used for scanning the exposed films in transparency mode. Scanned films were analyzed with inhouse written MATLAB codes.Results: Gamma index analysis of film measurement in comparison with TPS calculated dose resulted in high pass rates >90% for tolerance criteria of 1%/1 mm. The isodose overlay and linear dose profiles of film measured and computed dose distribution on sagittal and coronal plane were in close agreement.Conclusions: Through this study, the authors propose treatment verification QA method for Extend frame based fractionated Gamma Knife radiosurgery using EBT2 film.

61 RADIATION PROTECTION AND DOSIMETRY↗