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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Quantification of the Variability of Diaphragm Motion and Implications for Treatment Margin Construction

Purpose: To quantify the variability of diaphragm motion during free-breathing radiotherapy of lung patients and its effect on treatment margins to account for geometric uncertainties. Methods and Materials: Thirty-three lung cancer patients were analyzed. Each patient had 5-19 cone-beam scans acquired during different treatment fractions. The craniocaudal position of the diaphragm dome on the same side as the tumor was tracked over 2 min in the projection images, because it is both easily visible and a suitable surrogate to study the variability of the tumor motion and its impact on treatment margins. Intra-acquisition, inter-acquisition, and inter-patient variability of the respiratory cycles were quantified separately, as were the probability density functions (PDFs) of the diaphragm position over each cycle, each acquisition, and each patient. Asymmetric margins were simulated using each patient PDF and compared to symmetric margins computed from a margin recipe. Results: The peak-to-peak amplitude variability (1 SD) was 3.3 mm, 2.4 mm, and 6.1 mm for the intra-acquisition, inter-acquisition, and inter-patient variability, respectively. The average PDF of each cycle was similar to the sin{sup 4} function but the PDF of each acquisition was closer to a skew-normal distribution because of the motion variability. Despite large interfraction baseline variability, the PDF of each patient was generally asymmetric with a longer end-inhale tail because the end-exhale position was more stable than the end-inhale position. The asymmetry of the PDF required asymmetric margins around the time-averaged position to account for the position uncertainty but the average difference was 1.0 mm (range, 0.0-4.4 mm) for a sharp penumbra and an idealized online setup correction protocol. Conclusion: The respiratory motion is more irregular during the fractions than between the fractions. The PDF of the respiratory motion is asymmetrically distributed. Both the intra-acquisition variability and the PDF asymmetry have a limited impact on dose distributions and inferred margins. The use of a margin recipe to account for respiratory motion with an estimate of the average motion amplitude was adequate in almost all patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Quantifying the Interfractional Displacement of the Gastroesophageal Junction During Radiation Therapy for Esophageal Cancer

Purpose: Accounting for interfractional changes in tumor location improves the accuracy of radiation treatment delivery. The purpose of this study was to quantify the interfractional displacement of the gastroesophageal junction (GEJ) based on standard treatment setup in patients with esophageal cancer undergoing radiation therapy. Methods and Materials: Free-breathing four-dimensional computed tomography (4D-CT) datasets were acquired weekly from 22 patients during treatment for esophageal adenocarcinoma. Scans were registered to baseline (simulation) 4D-CT scans by using bony landmarks. The distance between the center of the GEJ contour on the simulation scan and the mean location of GEJ centers on subsequent scans was used to assess changes in GEJ location between fractions; displacement was also correlated with clinical and respiratory variables. Results: The mean absolute random error was 1.69 mm (range, 0.11-4.11 mm) in the lateral direction, 1.87 mm (range, 0.51-4.09 mm) in the anterior-posterior (AP) direction, and 3.09 mm (range, 0.99-6.16 mm) in the superior-inferior (SI) direction. The mean absolute systemic GEJ displacement between fractions was 2.88 mm lateral ({>=}5 mm in 14%), mostly leftward; 2.90 mm ({>=}5 mm in 14%) AP, mostly anterior; and 6.77 mm ({>=}1 cm in 18%) SI, mostly inferior. Variations in tidal volume and diaphragmatic excursion during treatment correlated strongly with systematic SI GEJ displacement (r = 0.964, p < 0.0001; and r = 0.944, p < 0.0001, respectively) and moderately with systematic AP GEJ displacement (r = 0.678, p = 0.0005; r = 0.758, p < 0.0001, respectively). Systematic displacement in the inferior direction resulted in higher-than-intended doses ({>=}60 Gy) to the GEJ, with increased hot-spot to the adjacent stomach and lung base. Conclusion: We found large (>1-cm) interfractional displacements in the GEJ in the SI (especially inferior) direction that was not accounted for when skeletal alignment alone was used for patient positioning. Because systematic displacement in the SI direction had dosimetric impact and correlated with tidal volume, better accounting for depth of breathing is needed to reduce interfractional variability.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

Spatially adaptive stochastic methods for fluid–structure interactions subject to thermal fluctuations in domains with complex geometries

We develop stochastic mixed finite element methods for spatially adaptive simulations of fluid–structure interactions when subject to thermal fluctuations. To account for thermal fluctuations, we introduce a discrete fluctuation–dissipation balance condition to develop compatible stochastic driving fields for our discretization. We perform analysis that shows our condition is sufficient to ensure results consistent with statistical mechanics. We show the Gibbs–Boltzmann distribution is invariant under the stochastic dynamics of the semi-discretization. To generate efficiently the required stochastic driving fields, we develop a Gibbs sampler based on iterative methods and multigrid to generate fields with O(N) computational complexity. Our stochastic methods provide an alternative to uniform discretizations on periodic domains that rely on Fast Fourier Transforms. To demonstrate in practice our stochastic computational methods, we investigate within channel geometries having internal obstacles and no-slip walls how the mobility/diffusivity of particles depends on location. Our methods extend the applicability of fluctuating hydrodynamic approaches by allowing for spatially adaptive resolution of the mechanics and for domains that have complex geometries relevant in many applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

A collision model for grain-resolving simulations of flows over dense, mobile, polydisperse granular sediment beds

We present a collision model for phase-resolved Direct Numerical Simulations of sediment transport that couple the fluid and particles by the Immersed Boundary Method. Typically, a contact model for these types of simulations comprises a lubrication force for particles in close proximity to another solid object, a normal contact force to prevent particles from overlapping, and a tangential contact force to account for friction. Our model extends the work of previous authors to improve upon the time integration scheme to obtain consistent results for particle-wall collisions. Furthermore, we account for polydisperse spherical particles and introduce new criteria to account for enduring contact, which occurs in many sediment transport situations. This is done without using arbitrary values for physically-defined parameters and by maintaining the full momentum balance of a particle in enduring contact. Lastly, we validate our model against several test cases for binary particle-wall collisions as well as the collective motion of a sediment bed sheared by a viscous flow, yielding satisfactory agreement with experimental data by various authors.

42 ENGINEERING↗
DOE OSTI2021

Energy based fracture initiation criterion for strain-crystallizing rubber-like materials with pre-existing cracks

Fracture prediction is indispensable for polymers, like rubbers, which have a broad range of applications mainly due to their high extensibility. The phenomenon known as strain-induced crystallization further contributes to the fracture toughness of certain rubbers. Here in this study, a criterion based on internal bond energy, incorporating the effects of crystallization, is proposed to predict fracture initiation in rubber-like materials with pre-existing cracks. First, a multi-scale mechanical model is developed for characterizing the behavior of rubber when subjected to both uniaxial and biaxial deformation states. At the microscale, both the amorphous and crystalline chain segments are modeled as elastic in order to consider the energy contribution by the molecular bond distortions. This internal energy is considered along with the entropic and crystalline free energy for each chain. In the chain model, the effects of loading condition and the relative orientation of a chain on its crystallinity are taken into account. At the macroscopic scale, an existing crystallinity distribution function is adapted and a mixed finite element formulation with an augmented Lagrangian multiplier is utilized to impose the incompressibility constraint. A non-affine maximal advance path constraint based homogenization model is utilized for bridging the two scales. Its potential to account for anisotropy in the stretched network compels the model to be preferable due to its physical significance, for the purpose of fracture modeling. The rigidity of the crystallites is accounted for by proposing a crystallite distortion energy in addition to the critical bond dissociation energy, for fracture initiation to occur. The model is validated by comparison with existing experimental results for both crystallizing and non-crystallizing rubbers. In addition to its potential to predict the material behavior when subjected to uniaxial and biaxial loading, the capability of the model to quantitatively estimate the effect of crystallization on fracture initiation is also verified.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Mesoscale modeling of electric double layer capacitors with three-dimensional ordered structures

This paper presents general mathematical formulations for simulating electric double layer capacitors (EDLCs) with three-dimensional ordered structures. For the first time, a general set of boundary conditions was derived in order to account for the Stern layer without simulating it in the computational domain. These boundary conditions were valid for planar, cylindrical, and spherical electrode particles or pores. They made possible the simulations of EDLCs with complex geometries while rigorously accounting for both the Stern and diffuse layers. The model also simultaneously accounted not only for 3D electrode morphology but also for finite ion size and field-dependent electrolyte dielectric permittivity. It was used to faithfully simulate the complex structure of an EDLC electrode consisting of ordered bimodal mesoporous carbon featuring both macropores and mesopores. Areal and gravimetric capacitances were predicted based on non-solvated and solvated ion diameters. These two cases set the upper and lower bounds for the predicted capacitances. The capacitances predicted using non-solvated ion diameter were found to be in good agreement with experimental data reported in the literature. All surfaces contributed to the overall capacitance of EDLCs. The gravimetric capacitance of different bimodal carbons increased linearly with increasing specific surface area corresponding to constant areal capacitance.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2012

Optical spectroscopy and excited state dynamics of CaMoO{sub 4}:Pr{sup 3+}

The luminescence properties of CaMoO{sub 4}:Pr{sup 3+} have been investigated in different experimental conditions in order to obtain information on the excitation and de-excitation pathways of this system. The structure of the emission spectrum depends on different factors: excitation conditions, doping level, temperature, etc. In addition, measurements carried out on single crystals and on micro- or nano-crystalline powders obtained by solid state reaction and sol-gel method have revealed that the morphology of the sample, and then the concentration of the lattice defects, strongly influences the excitation mechanism. These effects have been analysed in the light of available models and a general scheme accounting for the experimental observations has been proposed. - Graphical abstract: A general scheme is proposed in order to account for the complex dependence of the luminescence properties of the CaMoO{sub 4}:Pr{sup 3+} system on the experimental parameters including excitation wavelength, temperature, doping concentration, etc. Black-Small-Square Highlights: Black-Right-Pointing-Pointer Emission spectra of CaMoO{sub 4}:Pr{sup 3+} have been measured in different conditions. Black-Right-Pointing-Pointer Effects of the interaction between host and Pr{sup 3+} ions have been explored. Black-Right-Pointing-Pointer A 'host+active ion' scheme allows to account for the experimental observations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Co{sub 3}O{sub 4}-Co{sub 2}ZnO{sub 4} spinels: The case for a solid solution

In prior first-principles theoretical work we predicted a complete solid solution in the Co{sub 3}O{sub 4}-Co{sub 2}ZnO{sub 4} system, with a negligibly small mixing enthalpy. In this work we tested this prediction on bulk, large-grained specimens across the Co{sub 3}O{sub 4}-Co{sub 2}ZnO{sub 4} join, combining oxide melt solution calorimetry, differential scanning calorimetry, precise lattice parameter measurements, anomalous X-ray and neutron diffraction, and in situ electrical measurements. The calorimetric results confirm the presence of a solid solution at high temperatures, but with a large enthalpy of mixing that exceeds the predicted value. Because Co{sub 3}O{sub 4} and Co{sub 2}ZnO{sub 4} have essentially identical lattice parameters, this energetic destabilization must arise from factors other than the strain energy resulting from size mismatch. Changes in Co{sup 3+} spin states vs. temperature and zinc content are proposed to account for the positive excess enthalpy, and may also provide additional entropy to stabilize the solid solution at high temperature. - Graphical abstract: The first-principles theoretical prediction of a complete solid solution in Co{sub 3}O{sub 4}-Co{sub 2}ZnO{sub 4} spinels has been confirmed experimentally by calorimetric, structural, and electrical measurements. The large mixing enthalpy observed exceeds the predicted value and cannot be accounted for by strain or cation distribution contributions alone, since such effects are small in this system; instead, changes in the spin state of Co{sup 3+} are proposed to account for the mixing thermodynamics. Highlights: Black-Right-Pointing-Pointer Experiments confirm theory prediction of a solid solution in Co{sub 3}O{sub 4}-Co{sub 2}ZnO{sub 4} spinels. Black-Right-Pointing-Pointer Thermodynamics of mixing studied by calorimetric, electrical, structural methods. Black-Right-Pointing-Pointer Cation distributions found to be mostly normal for various compositions. Black-Right-Pointing-Pointer Mixing enthalpy is larger than prediction and inconsistent with strain effects. Black-Right-Pointing-Pointer Changes in Co{sup 3+} spin state proposed as source of large mixing enthalpy/entropy.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Shale gas transport model in 3D fractal porous media with variable pore sizes

A model for gas transport in shale is proposed by accounting for three major fluid flow mechanisms in shale stratum, which is modeled as a 3D fractal media. The proposed apparent permeability of shale is an analytical expression that also accounts for heterogeneous pore sizes in shale stratum, and is verified using experimental datasets for methane and helium flow in shale. Results of sensitivity analysis indicate that surface diffusion of adsorbed gas plays an important role, specifically in smaller pores, while surface diffusion would be negligible in larger pores. Further, the proposed model shows that flow due to surface diffusion decreases moderately with the increase of isosteric adsorption heat, while it increases significantly with the increase of the maximum adsorption capacity. In conclusion, one of the key novelties of the proposed permeability model is that it accounts for pore size distribution to reveal novel insights on gas transport in shale that can be used to optimize gas production by operational controls (e.g. controlling reservoir pressure) as flow regimes change with time.

58 GEOSCIENCES↗
DOE OSTI2016

Microstructure and hydrogenation properties of a melt-spun non-stoichiometric Zr-based Laves phase alloy

Alloy with composition of Zr{sub 0.9}Ti{sub 0.1}V{sub 1.7} off normal stoichiometric proportion is selected to investigate the effect of defects introduced by non-stoichiometry on hydrogenation kinetics of Zr–Ti–V Laves phase alloys. Microstructure and phase constituent of melt-spun ribbons have been investigated in this work. The activation process, hydrogenation kinetics, thermodynamics characteristics and hydride phase constituent of as-cast alloy and melt-spun ribbons are also compared. Comparing with the as-cast alloy, the dominant Laves phase ZrV{sub 2} is preserved, V-BCC phase is reduced and α-Zr phase is replaced by a small amount of Zr{sub 3}V{sub 3}O phase in melt-spun ribbons. Melt-spun ribbons exhibit easy activation and fast initial hydrogen absorption on account of the increased specific surface area. However, the decrease in unit cell volume of the dominant phase leads to the decrease in hydrogen absorption capacity. Melt-spinning technique raises the equilibrium pressure and decreases the stability of hydride due to the decrease of unit cell volume and the elimination of α-Zr phase, respectively. Melt-spun ribbons with fine grains show improved hydrogen absorption kinetics comparing with that of the as-cast alloy. Meanwhile, the prevalent micro twins observed within melt-spun ribbons are believed to account for the improved hydrogen absorption kinetics. - Highlights: • Role of defects on hydrogenation kinetics of Zr-based alloys is proposed. • Microstructure and hydrogenation properties of as-cast/melt-spun alloy are compared. • Melt-spinning technique improves the hydrogenation kinetics of Zr{sub 0.9}Ti{sub 0.1}V{sub 1.7} alloy. • Refined grains and twin defects account for improved hydrogen absorption kinetics.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Statistical characterization of twin transmission across grain boundaries in magnesium

Here, a detailed statistical analysis of twin transmission (TT) across grain boundaries is performed in rolled, commercial purity magnesium compressed along the rolling direction. EBSD images are acquired from two different cuts: a section containing the rolling (RD) and normal (ND) directions; and a section at 35° to the ND which contains transverse direction (TD). An automated twinning analysis software, METIS, is used to obtain the statistical correlations between deformation twins and other microstructural features by analyzing EBSD microstructures comprising thousands of grains and twins. This detailed statistical analysis reveals that the TT propensity is sensitive to the grain boundary (GB) misorientation angle but not to the GB misorientation axis. Specifically, TT propensity decreases with increasing GB misorientation angle; however, the decreasing trend is not monotonic. Further, the detailed analysis of TT events combining macroscopic Schmid factor and the geometric measures (m’: accounts for the alignment of both twin plane normal and shear directions; m”: accounts for the alignment of only twin shear directions; and m”’: accounts for the alignment of only twin plane normal) helps in understanding and identifying the process of twin-pair formation, i.e., co-nucleation versus transmission, also to identify the role of local stresses at GBs induced by inter-grain interaction versus twinning shear transformation processes. In addition, Bayesian inference is used to draw statistically meaningful conclusions as to the likelihood of transmission given misorientation angles. Lastly, twin chain frequency as a function of chain length is predicted using the probability distribution obtained from the Bayesian inference and compared with the actual data from the EBSD microstructures.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Under conditions of large geometric miss, tumor control probability can be higher for static gantry intensity-modulated radiation therapy compared to volume-modulated arc therapy for prostate cancer

The purpose of this work was to compare static gantry intensity-modulated radiation therapy (IMRT) with volume-modulated arc therapy (VMAT) in terms of tumor control probability (TCP) under scenarios involving large geometric misses, i.e., those beyond what are accounted for when margin expansion is determined. Using a planning approach typical for these treatments, a linear-quadratic–based model for TCP was used to compare mean TCP values for a population of patients who experiences a geometric miss (i.e., systematic and random shifts of the clinical target volume within the planning target dose distribution). A Monte Carlo approach was used to account for the different biological sensitivities of a population of patients. Interestingly, for errors consisting of coplanar systematic target volume offsets and three-dimensional random offsets, static gantry IMRT appears to offer an advantage over VMAT in that larger shift errors are tolerated for the same mean TCP. For example, under the conditions simulated, erroneous systematic shifts of 15 mm directly between or directly into static gantry IMRT fields result in mean TCP values between 96% and 98%, whereas the same errors on VMAT plans result in mean TCP values between 45% and 74%. Random geometric shifts of the target volume were characterized using normal distributions in each Cartesian dimension. When the standard deviations were doubled from those values assumed in the derivation of the treatment margins, our model showed a 7% drop in mean TCP for the static gantry IMRT plans but a 20% drop in TCP for the VMAT plans. Although adding a margin for error to a clinical target volume is perhaps the best approach to account for expected geometric misses, this work suggests that static gantry IMRT may offer a treatment that is more tolerant to geometric miss errors than VMAT.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2017

Importance of deformable image registration and biological dose summation in planning of radiotherapy retreatments

The purpose of this study is to evaluate the effect of nonrigid and fractionation-corrected dose summation on total doses in radiotherapy and to demonstrate the benefits of such dose summation on clinical decision-making for planning of retreatments. Dose summation of organs at risk (OARs) was investigated for 3 clinical cases with need of retreatment to the same site: head and neck, brain, and mediastinum. Three different summation methods over old and new radiotherapy treatment plans are presented and compared: (1) rigid raw sum with rigid registration of the planning images and direct dose summing; (2) deformable raw sum with deformable image registration and direct dose summing; and (3) deformable biological sum with deformable registration and takes into account the dose per fraction in biological manner in certain critical organs. In 2 cases, a user-defined dose downscaling is applied to take into account the time between the treatments and the healing from the radiation-induced effects. Of the 3 summation methods presented, the deformable biological sum was considered to offer the most biologically plausible account of the treatment. There were remarkable differences between near-maximum doses (D0.1cc) and dose-volume histogram (DVH) curves for OARs between different summation methods. The differences between deformable raw sum and rigid raw sum D0.1cc doses are in the range from −8 Gy to 2 Gy. Similarly, the deviation was from −14 Gy to 5 Gy for the deformable biological sum compared with the rigid raw sum. These differences come from incorrect summation of doses in the rigid raw sum case, and from the dose per fraction effect in biological summation. We conclude that computing the 3-dimensional deformable biological summation could be a valuable tool for treating patients with complex retreatments. It has the potential to assist the oncologist in refining plans for maximally curative doses while respecting appropriate tissue tolerances.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2023

Design of a prototypical natural circulation water-based reactor cavity cooling system (RCCS) for a pebble-bed generic FHR

A prototypical natural circulation water-based reactor cavity cooling system (RCCS) for the UC Berkeley Mark-1 pebble-bed gFHR is designed based on one-dimensional thermal hydraulics modeling and optimization implemented in an in-house MATLAB code. The model employs a lumped core consisting of fuel pebble and graphite pebble regions, while the graphite reflector, vessel, and RCCS are represented as separate but energy-coupled regions. The model is derived based on steady state energy balance equations accounting for conductive heat transfer from the lumped core to the vessel and subsequent radiative heat transfer to the RCCS and convective heat transfer in the water. Further, mass flow rate is calculated based on momentum and thermal energy balance in the RCCS. Starting with ANL’s water NSTF as baseline, effects of RCCS design parameters such as size of the plate between pipes, pipe diameter, source-to-sink distance, surface emissivity, and pitch from the core are examined in an integral effects framework which accounts for subsequent variation of the mass flow rate, number of pipes, convection coefficient, mean region and surface temperatures, radiative view factors, and water outlet temperature. The importance of including a prototypical reactor design in RCCS design calculations is emphasized as the calculations show that temperature drops from the core to the RCCS fluid to transfer the heat tend to be the limitation not the heat removal capacity of the fluid. A closed-loop design is obtained with capability to safely remove up to 0.72% of the nominal reactor power at maximum estimated peak conditions and 0.40% at shutdown. The design is based on physics calculations and does not account for economic optimization.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2025

Leptodermic corrections to the TOV equations and nuclear astrophysics within the effective surface approximation

The macroscopic model for a neutron star (NS) as a liquid drop at the equilibrium is used to extend the Tolman-Oppenheimer-Volkoff (TOV) equations taking into account the gradient terms responsible for the system surface. The parameters of the Schwarzschild metric in the spherical case are found with these surface corrections to the known leading (zero) order of the leptodermic approximation a/R << 1, where a is the NS effective-surface (ES) thickness, and R is the effective NS radius. The energy density $\mathscr{E}$ is considered in a general form including the functions of the particle number density and of its gradient terms. The macroscopic gravitational component $Φ$(ρ) of the energy density is taken into account in the simplest form as expansion in powers of $ρ$ – $\overline{ρ}$, where $\overline{ρ}$ is the saturation density, up to second order, in terms of its contributions to the separation particle energy and incompressibility. Density distributions ρ across the NS ES in the normal direction to the ES, which are derived in the simple analytical form at the same leading approximation, was used for the derivation of the modified TOV (MTOV) equations by accounting for their NS surface corrections. As a result, the MTOV equations are analytically solved at first order and the results are compared with the standard TOV approach of the zero order.

Magner, A. G. [Institute for Nuclear Research, Kyi↗
DOE OSTI2014

Methodology to design a municipal solid waste generation and composition map: A case study

Highlights: • To draw a waste generation and composition map of a town a lot of factors must be taken into account. • The methodology proposed offers two different depending on the available data combined with geographical information systems. • The methodology has been applied to a Spanish city with success. • The methodology will be a useful tool to organize the municipal solid waste management. - Abstract: The municipal solid waste (MSW) management is an important task that local governments as well as private companies must take into account to protect human health, the environment and to preserve natural resources. To design an adequate MSW management plan the first step consist in defining the waste generation and composition patterns of the town. As these patterns depend on several socio-economic factors it is advisable to organize them previously. Moreover, the waste generation and composition patterns may vary around the town and over the time. Generally, the data are not homogeneous around the city as the number of inhabitants is not constant nor it is the economic activity. Therefore, if all the information is showed in thematic maps, the final waste management decisions can be made more efficiently. The main aim of this paper is to present a structured methodology that allows local authorities or private companies who deal with MSW to design its own MSW management plan depending on the available data. According to these data, this paper proposes two ways of action: a direct way when detailed data are available and an indirect way when there is a lack of data and it is necessary to take into account bibliographic data. In any case, the amount of information needed is considerable. This paper combines the planning methodology with the Geographic Information Systems to present the final results in thematic maps that make easier to interpret them. The proposed methodology is a previous useful tool to organize the MSW collection routes including the selective collection. To verify the methodology it has been successfully applied to a Spanish town.

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

Experimental tests on commercial Sweet Product Residue (SPR) as a suitable feed for anaerobic bioenergy (H2 + CH4) production

Highlights: • Post-sale refuses was tested as feed for two-step-Anaerobic Digestion (TSAD). • Extrusion was assessed at pilot plant scale process to remove the packaging. • NaOH Pretreatment was evaluated in order to increase the refuses digestibility. • H{sub 2} + CH{sub 4} production via TSAD process was experimentally evaluated. • Energy Sustainability Index were used to evaluate the process: pretreatment + TSAD. - Abstract: Food stores can find themselves in the position of having to dispose of different types of products, such as snacks, confectionery, prepackaged food, drinks and others, Sweet Product Residue (SPR), which presents a great opportunity to produce energy through Anaerobic Digestion (AD), due to its high sugar, carbohidrate and fat contents. In order to valorise SPR, this paper takes into consideration the all necessary treatments; owing the fact that the refuses are constitute by an organic part and packaging (plastic, paper and their combinations), a pretreatment able to remove the latter is necessary. SPR refuse was initially subjected to novel pretreatment approach: extrusion at 200 atm to remove the packaging, and a Basic Pre-treatment (BP) then tested through a Two-Stage AD (TSAD) process, for H{sub 2} and CH{sub 4} productions. The experimental results were analysed considering three parameters: Efficiency (ξ), which takes into account the quantity of the energy produced as hydrogen plus methane that the bioreaction is able to extract; Efficacy (η), which takes into account the efficiency of the actual test, compared with that obtained from a reference test carried out with glucose; Energy Sustainability Index (ESI), which takes into account the total amount of energy produced as H{sub 2} plus CH{sub 4}, and the amount of energy consumed to pre-treat the refuse. The effectiveness of the extrusion process in removing the packaging was very high: about 80% of the organic part present in the SPR was recovered. The obtained results have pointed out that SPR is suitable for energy valorization process: ξ = 50%, η = 0.67 and ESI = 24.4, without the need of basic pre-treatment.

09 BIOMASS FUELS↗