Backscatter Energy Research Articles

Medium‐range global ensemble prediction system at 12 km horizontal resolution and its preliminary validation

AbstractForecasts of high‐impact weather systems require sufficiently high resolution of state‐of‐the‐art numerical models in order to resolve the small‐scale features. At the National Centre for Medium Range Weather Forecasting (NCMRWF) in India, a global ensemble prediction system (EPS—called the NEPS) has been implemented operationally at 12 km horizontal grid size. The NEPS configuration is based on the UK Met Office Global and Regional Ensemble Prediction System (MOGREPS). Initial condition perturbations are generated by the ensemble transform Kalman filter (ETKF) method. Model uncertainties are taken care of by stochastic kinetic energy backscatter (SKEB) and random parameters (RP) schemes. Forecast perturbations obtained from 6 hr short forecasts of 22 ensemble members are updated by the ETKF four times a day (0000, 0600, 1200 and 1800 UTC). Perturbations of surface parameters such as sea‐surface temperature, soil moisture content and soil temperature are also included in the new NEPS. The NEPS aims to provide 10 day probabilistic long forecasts using 23 ensemble members (22 perturbed plus one control). The long forecast provided at 0000 UTC is the combination of 11 members from the 0000 UTC cycle and lagged 11 members from the 1200 UTC cycle. The new NEPS shows improvements in terms of forecast agreement among the members in comparison with the previously operational NEPS that was running at 33 km horizontal grid size with 44 perturbed members. The ratio between the root mean square error of the ensemble mean and ensemble spread as a function of lead time has improved in both the Northern and Southern Hemispheres in the new NEPS.

Diurnal Effects of Regional Soil Moisture Anomalies on the Great Plains Low-Level Jet

AbstractThe Great Plains (GP) low-level jet (GPLLJ) contributes to GP warm season water resources (precipitation), wind resources, and severe weather outbreaks. Past research has shown that synoptic and local mesoscale physical mechanisms (Holton and Blackadar mechanisms) are required to explain GPLLJ variability. Although soil moisture–PBL interactions are central to local mechanistic theories, the diurnal effect of regional soil moisture anomalies on GPLLJ speed, northward penetration, and propensity for severe weather is not well known. In this study, two 31-member WRF-ARW stochastic kinetic energy backscatter scheme ensembles simulate a typical warm season GPLLJ case under CONUS-wide wet and dry soil moisture scenarios. In the GP (24°–48°N, 103°–90°W), ensemble mean differences in sensible heating and PBL height of 25–150 W m−2 and 100–700 m, respectively, at 2100 UTC (afternoon) culminate in GPLLJ 850-hPa wind speed differences of 1–4 m s−1 12 hours later (0900 UTC; early morning). Greater heat accumulation in the daytime PBL over dry soil impacts the east–west geopotential height gradient in the GP (synoptic conditions and Holton mechanism) resulting in a deeper thermal low in the northern GP, causing increases in the geostrophic wind. Enhanced daytime turbulent mixing over dry soil impacts the PBL structure (Blackadar mechanism), leading to increased ageostrophic wind. Overnight geostrophic and ageostrophic winds constructively interact, leading to a faster nocturnal GPLLJ over dry soil. Ensemble differences in CIN (~50–150 J kg−1) and CAPE (~500–1000 J kg−1) have implications for severe weather predictability.

Effect of flow topology on the kinetic energy flux in compressible isotropic turbulence

The effects of flow topology on the subgrid-scale (SGS) kinetic energy flux in compressible isotropic turbulence is studied. The eight flow topological types based on the three invariants of the filtered velocity gradient tensor are analysed at different scales, along with their roles in the magnitude and direction of kinetic energy transfer. The unstable focus/compressing (UFC), unstable node/saddle/saddle (UN/S/S) and stable focus/stretching (SFS), are the three predominant topological types at all scales; they account for at least 75 % of the flow domain. The UN/S/S and SFS types make major contributions to the average SGS flux of the kinetic energy from large scales to small scales in the inertial range. The unstable focus/stretching (UFS) topology makes a contribution to the reverse SGS flux of kinetic energy from small scales to large scales. In strong compression regions, the average contribution of the stable node/saddle/saddle (SN/S/S) topology to the SGS kinetic energy flux is positive and is predominant over those of other flow topologies. In strong expansion regions, the UFS topology makes a major contribution to the reverse SGS flux of the kinetic energy. As the turbulent Mach number increases, the increase of volume fraction of the UFS topological regions leads to the increase of the SGS backscatter of kinetic energy. The SN/S/S topology makes a dominant contribution to the direct SGS flux of the compressible component of the kinetic energy, while the UFS topology makes a dominant contribution to the reverse SGS flux of the compressible component of the kinetic energy.

Effect of grain boundary misorientation angle on diffusion behavior in molybdenum-tungsten systems

Grain boundary (GB) diffusion plays a key role in the long-term service processes of engineering materials at elevated temperatures. GB diffusion processes are strongly relying on the misorientation angle of the two adjacent grains. However, the orientation dependence of GB diffusion is not well understood. In this work, two types of tungsten coating were deposited onto a substrate consisting of a single molybdenum crystal to forming diffusion couples. The diffusion profiles of isolated GBs have been measured by electron backscatter diffraction and energy dispersive X-ray spectroscopy. The effect of the tungsten GB misorientation angle (θ) on the diffusivity of molybdenum was investigated. GB structures with different misorientation angles were resolved using high-resolution transmission electron microscopy. As θ increased from 5° to 18°, the spacing between the dislocations composing the GBs decreased from greater than 10 to 3 atomic spaces. Furthermore, when θ was greater than 18° a 0.53 nm wide ordered structure was formed, and this structural change increased the GB energy. Consequently, the GB diffusion coefficient increased by 3- and 7- orders of magnitude fold as compared to the volume diffusion coefficient for low- and high-angle GBs, respectively. The GB energies were approximately 1.1 and 2.1 J m−2 in low- and high-angle GBs, respectively. This is the first time that tungsten GB energies were determined through experimental method.

Functional bimetallic joints of Ti6Al4V to SS410

Bimetallic structures provide a unique solution to achieve site-specific functionalities and enhanced-property capabilities in engineering systems but suffer from bonding compatibility issues. Materials such as titanium alloy (Ti6Al4 V) and stainless steel (SS410) have distinct attractive properties but are impossible to reliably weld together using traditional processes. To this end, a laser-based directed energy deposition (DED) system was used to fabricate bimetallic joint of Ti6Al4 V and SS410 keeping niobium (Nb) as a diffusion barrier layer. Both shear and compression tests were used to characterize the joint’s strength, and compared with the base materials. The bimetallic-joint shear and compressive yield strengths were 419 ± 3 MPa (∼114% of SS410) and 560 ± 4 MPa (∼169% of SS410), respectively. The increase in interfacial shear and compressive yield strengths over the base material indicates strong metallurgical bonding between the base materials and the interlayer, Nb. Proof-of-concept part for direct application of the bimetallic joint was demonstrated by welding base metals, end-to-end, to the joint. The interfacial microstructures, elemental diffusion and phases, including failure modes were examined using secondary and backscatter electron imaging, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The bimetallic-joint interfaces were free from brittle intermetallic compounds such as FeTi and Fe2Ti that are generally responsible for weak bond strength.

Deterministic and stochastic parameterizations of kinetic energy backscatter in the NEMO ocean model in Double-Gyre configuration

Eddy-permitting numerical ocean models often resolve mesoscale turbulence only partly, which leads to underestimation of eddy kinetic energy (EKE). Mesoscale dynamics can be amplified by using kinetic energy backscatter (KEB) parameterizations returning energy from the unresolved scales. We consider two types of KEB: stochastic and negative viscosity ones. The tuning of their amplitudes is based on a local budget of kinetic energy, thus, they are "energetically-consistent" KEBs. In this work, KEB parameterizations are applied to the NEMO ocean model in Double-Gyre configuration with an eddy-permitting resolution (1/4 degree). To evaluate the results, we compare this model with an eddy-resolving one (1/9 degree). We show that with the KEBs the meridional overturning circulation (MOC), meridional heat flux, and sea surface temperature (SST) can be significantly improved. In addition, a better match has been found between the time power spectra of the eddy-permitting and the eddy-resolving model solutions.

Validation of Snow Multibands in the Comma Head of an Extratropical Cyclone Using a 40-Member Ensemble

Abstract This paper investigates the ability of the Weather Research and Forecasting (WRF) Model in simulating multiple small-scale precipitation bands (multibands) within the extratropical cyclone comma head using four winter storm cases from 2014 to 2017. Using the model output, some physical processes are explored to investigate band prediction. A 40-member WRF ensemble was constructed down to 2-km grid spacing over the Northeast United States using different physics, stochastic physics perturbations, different initial/boundary conditions from the first five perturbed members of the Global Forecast System (GFS) Ensemble Reforecast (GEFSR), and a stochastic kinetic energy backscatter scheme (SKEBS). It was found that 2-km grid spacing is adequate to resolve most snowbands. A feature-based verification is applied to hourly WRF reflectivity fields from each ensemble member and the WSR-88D radar reflectivity at 2-km height above sea level. The Method for Object-Based Diagnostic Evaluation (MODE) tool is used for identifying multibands, which are defined as two or more bands that are 5–20 km in width and that also exhibit a >2:1 aspect ratio. The WRF underpredicts the number of multibands and has a slight eastward position bias. There is no significant difference in frontogenetical forcing, vertical stability, moisture, and vertical shear between the banded versus nonbanded members. Underpredicted band members tend to have slightly stronger frontogenesis than observed, which may be consolidating the bands, but overall there is no clear linkage in ambient condition errors and band errors, thus leaving the source for the band underprediction motivation for future work.

Micropillar compression investigation of size effect on microscale strength and failure mechanism of Calcium-Silicate-Hydrates (C-S-H) in cement paste

The compressive strength and failure of concrete and cement exhibit strong size effect over various length scales. To investigate possible size effect on compressive strength and failure mechanism of Calcium-Silicate-Hydrates (C-S-H) in cement paste, micropillar compression experiments were performed on micropillar geometries fabricated by focused ion beam milling on potential C-S-H locations identified through coupled backscatter electron imaging (BSE) and energy dispersive spectroscopy (EDS) analysis. The compressive strength of C-S-H (181–1145 MPa) measured from C-S-H micropillars of varying diameters indicated presence of a size effect with strong increase in strength with decreasing diameter. The deformation mode at failure also exhibited size effect: the dominant failure mode changed from axial splitting to plastic crushing as the pillar diameter was decreased. The observed relationship between strength and pillar diameter can be modeled by an inverse square root dependency which closely corresponds to Bazant's scaling law of quasi-brittle failure.

Corrosion of Candidate Alloys in Molten LiCl-Li2O-Li for Pyroprocessing of Used Nuclear Fuel

Pyrochemical reprocessing of used nuclear fuel (UNF) requires large structural process vessels and functional components fabricated from stainless steel 316L (SS316L) or another high-temperature molten salt-compatible material like Inconel 625 (I625). The unique chemistry of the molten salt electrolyte during processing of UNF leads to complex interactions between container materials and the electrolyte that have been well documented by our group. In the head-end process to incorporate oxide UNF into the pyrochemical reprocessing scheme, LiCl with 1-2 wt. % Li2O is utilized as an electrolyte to facilitate the electrolytic reduction of UO2 via the Fray-Farthing-Chem (FFC) process. The Li+ reduction potential is quite close to the UO2 reduction potential and it is generally recognized that lithium metal will be produced at the cathode during the reduction process. While much of the metallic lithium further facilitates the reduction of UO2 via a metallothermic pathway, forming Li2O, a fraction of the metallic lithium dissolves or otherwise disperses into the molten salt. The metallic lithium then diffuses throughout the salt and reacts with process vessels and other components. To further understand corrosion in these conditions, SS316L and I625 coupons were exposed to LiCl-1 wt. % Li2O-Li and LiCl-2 wt. % Li­2O-Li with lithium metal concentrations of 0, 0.3, 0.6 or 1.0 wt. %. These samples were then studied using focused ion beam (FIB) milling, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS). Results from these studies will be discussed. Acknowledgements: The authors thank Zachary Karmiol, research scientist at Materials Characterization Nevada, for technical input. One of the authors, JM, acknowledges the Graduate Research Fellowship from the US National Science Foundation. This work was supported by the United States Department of Energy (DOE) under contracts, DE-NE0008262, DE-NE0008236, and DE-NE0008572, and the United States Nuclear Regulatory Commission (NRC) under Contract NRC-HQ-13-G-38-0027. Dr. Kenny Osborne and Ms. Nancy Hebron-Israel serve as the DOE and NRC award program managers, respectively. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1447692.

Stochastic and deterministic kinetic energy backscatter parameterizations for simulation of the two-dimensional turbulence

AbstractThe problem of modelling 2D isotropic turbulence in a periodic rectangular domain excited by the forcing pattern of prescribed spatial scale is considered. This setting could be viewed as the simplest analogue of the large scale quasi-2D circulation of the ocean and the atmosphere. Since the direct numerical simulation (DNS) of this problem is usually not possible due to the high computational costs we explore several possibilities to construct coarse approximation models and corresponding subgrid closures (deterministic or stochastic). The necessity of subgrid closures is especially important when the forcing scale is close to the cutoff scale of the coarse model that leads to the significant weakening of the inverse energy cascade and large scale component of the system dynamics.The construction of closures is based on thea priorianalysis of the DNS solution and takes into account the form of a spatial approximation scheme used in a particular coarse model. We show that the statistics of a coarse model could be significantly improved provided a proper combination of deterministic and stochastic closures is used. As a result we are able to restore the shape of the energy spectra of the model. In addition the lagged auto correlations of the model solution as well as its sensitivity to external perturbations fit the characteristics of the DNS model much better.

Energetically consistent scale‐adaptive stochastic and deterministic energy backscatter schemes for an atmospheric model

AbstractCurrent climate models still suffer from many biases which are partly due to excessive subgrid‐scale dissipation. Here we systematically develop energetically consistent stochastic energy backscatter (SEB) and deterministic energy backscatter (DEB) parametrization schemes. We implement our schemes in a simplified spectral atmospheric General Circulation Model (GCM). It is shown that the SEB scheme performs better than the DEB scheme at low horizontal resolutions (T21 and T31), whereas the performance of both schemes becomes comparable as the resolution increases to T42 when comparing with our reference simulation at T127 resolution. The energy backscatter parametrization schemes improve eddy variability in low‐resolution models and correctly capture the dominant mode of zonal‐mean zonal wind variability. The autocorrelation time‐scale of low‐resolution models is also found to be more consistent with the reference simulation when applying the SEB and DEB parametrizations. Our schemes are scale‐adaptive and computationally efficient.

Thermomechanical fatigue behaviour of aged heat resistant austenitic alloys

The increasing demands for efficiency and flexibility result in more severe operating conditions for the materials used in critical components of biomass power plants. These operating conditions involve higher temperature ranges, more pronounced environmental effects and cyclic operations. Austenitic stainless steels have shown to possess promising high temperature properties which makes them suitable as candidates for critical components in biomass power plant. However, their behaviour under such conditions is not yet fully understood. This work investigates three commercial austenitic alloys: Esshete 1250, Sanicro 25 and Sanicro 31HT. The alloys were subjected to in-phase (IP) thermomechanical fatigue (TMF) testing under strain-control in the temperature range of 100–800 °C. Both virgin and pre-aged TMF specimens were tested in order to simulate service degradation resulting from long-term usage. The results show that the pre-aged specimens suffered shorter TMF-life compared to the virgin specimens. The scanning electron microscopy methods electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) were used to analyse and discuss active failure and deformation mechanisms. The difference in TMF-life produced by the two testing conditions was attributed to an embrittling effect by precipitation, reduced creep properties and oxidation assisted cracking.

Fabrication of thin sandwiched 142,150Nd targets for HYRA spectrometer experiments

Abstract Sandwiched 142 , 150 Nd targets of thickness ( ∼ 100– 150 μ g /cm 2 ) have been fabricated between two carbon layers of different thickness ( ∼ 30 μ g /cm 2 and ∼ 10 μ g /cm 2 ) using the thermal evaporation technique in the diffusion pump based coating unit at the target lab of Inter University Accelerator Center (IUAC), New Delhi. Thickness and purity measurement of the targets have been confirmed by using the Rutherford backscattering spectrometry (RBS) technique and energy dispersive X-ray fluorescence (EDXRF) measurement present at IUAC, New Delhi and Panjab University, Chandigarh, respectively. These targets have been successfully used in a recent experiment to measure evaporation-residue (ER) cross section and spin distribution of ERs in the hybrid recoil mass analyzer (HYRA) facility present at IUAC.

The Taiwan WRF Ensemble Prediction System: Scientific Description, Model-Error Representation and Performance Results

The Taiwan mesoscale ensemble prediction system (EPS) based on the Weather Research and Forecast model (WRF), also called WEPS, is designed to provide reliable ensemble forecasts for the East Asian region centered on Taiwan. The most skillful ensemble is obtained if model-uncertainty is represented in addition to initial condition uncertainty. A number of numerical prediction experiments are conducted to obtain the optimal configuration consisting of multiple physics-schemes, and two stochastic parameterization schemes: The Stochastic-Kinetic Energy Backscatter (SKEB) Scheme and the Stochastically Perturbed of Physics-Tendency (SPPT) scheme. The performance of the best configuration of WEPS is objectively verified against ECMWF reanalysis and a high-resolution simulation. Further analysis finds little impact of the stochastic schemes on quantitative precipitation forecasts and a single Typhoon case study. We conclude that for best performance over the East Asian domain, stochastic parameterizations alone are not sufficient to represent model-uncertainty and need to be augmented with a multi- physics suite.

Ocean kinetic energy backscatter parametrizations on unstructured grids: Impact on mesoscale turbulence in a channel

We present a new energy backscatter parametrization for primitive equation ocean models at eddy-permitting resolution, specifically for unstructured grids. Traditional eddy parametrizations in terms of viscosity closures lead to excessive dissipation of kinetic energy when used with eddy-permitting meshes. Implemented into the FESOM2 ocean model, the backscatter parametrization leads to a more realistic total dissipation of kinetic energy. It maintains a reservoir of dissipated energy and reinjects this subgrid energy at larger scales at a controlled rate. The separation between dissipation and backscatter scales is achieved by using different-order differential operators and/or spatial smoothing. This ensures numerical model stability.We perform sensitivity studies with different choices of parameter settings and viscosity schemes in a configuration with a baroclinically unstable flow in a zonally reentrant channel with a horizontally uniform mesh. The best backscatter setup substantially improves eddy-permitting simulations at 1/4° and 1/6° resolution, bringing them close to a 1/12° eddy-resolving reference. Improvements are largest for levels of kinetic energy and variability in temperature and vertical velocity. A selected optimal default scheme is then tested in a mixed resolution setup – a channel with narrow transitions between an eddy-permitting and an eddy-resolving subdomain. The backscatter scheme is able to adapt dynamically to the different resolutions and moves the diagnostics closer to the high resolution reference throughout the domain.Our study is a first step toward using backscatter in global variable-mesh ocean models and suggests potential for substantial improvements of ocean mean state and variability at reduced computational cost.

A methodology for sensitivity analysis of spatial features in forecasts: the stochastic kinetic energy backscatter scheme

Stochastic kinetic energy backscatter schemes (SKEBSs) are introduced in numerical weather forecast models to represent uncertainties related to unresolved subgrid‐scale processes. These schemes are formulated using a set of parameters that must be determined using physical knowledge and/or to obtain a desired outcome. Here, a methodology is developed for assessing the effect of four factors on spatial features of forecasts simulated by the SKEBS‐enabled Weather Research and Forecasting model. The four factors include two physically motivated SKEBS parameters (the determining amplitude of perturbations applied to stream function and potential temperature tendencies), a purely stochastic element (a seed used in generating random perturbations) and a factor reflecting daily variability. A simple threshold‐based approach for identifying coherent objects within forecast fields is employed, and the effect of the four factors on object features (e.g. number, size and intensity) is assessed. Four object types are examined: upper‐air jet streaks, low‐level jets, precipitation areas and frontal boundaries. The proposed method consists of a set of standard techniques in experimental design, based on the analysis of variance, tailored to sensitivity analysis. More specifically, a Latin square design is employed to reduce the number of model simulations necessary for performing the sensitivity analysis. Fixed effects and random effects models are employed to assess the main effects and the percentage of the total variability explained by the four factors. It is found that the two SKEBS parameters do not have an appreciable and/or statistically significant effect on any of the examined object features.

Photon and electron backscatter dose and energy spectrum analysis around Lipiodol using flattened and unflattened beams.

PurposeThe aim of the current study was to evaluate the backscatter dose and energy spectrum from the Lipiodol with flattening filter (FF) and flattening filter‐free (FFF) beams. Moreover, the backscatter range, that was defined as the backscatter distance (BD) are revealed.Methods6 MVX FF and FFF beams were delivered by TrueBeam. Two dose calculation methods with Monte Carlo calculation were used with a virtual phantom in which the Lipiodol (3 × 3 × 3 cm3) was located at a depth of 5.0 cm in a water‐equivalent phantom (20 × 20 × 20 cm3). The first dose calculation was an analysis of the dose and energy spectrum with the complete scattering of photons and electrons, and the other was a specified dose analysis only with scattering from a specified region. The specified dose analysis was divided into a scattering of primary photons and a scattering of electrons.ResultsThe lower‐energy photons contributed to the backscatter, while the high‐energy photons contributed the difference of the backscatter dose between the FF and FFF beams. Although the difference in the dose from the scattered electrons between the FF and FFF beams was within 1%, the difference of the dose from the scattered photons between the FF and FFF beams was 5.4% at a depth of 4.98 cm.ConclusionsThe backscatter range from the Lipiodol was within 3 mm and depended on the Compton scatter from the primary photons. The backscatter dose from the Lipiodol can be useful in clinical applications in cases where the backscatter region is located within a tumor.

Destructive and Non-destructive Assessment of the Thickness of Oxide Layers of Super-heater Tubes

Tubes of super-heaters and heaters used in conventional power plants are exposed to coolant and high temperatures. The growing oxide layer on the inner surface reacts over time as a heat insulator on the water side and reduces heat transfer through the wall of the tube. A relatively thin oxide layer already contributes to the boiler efficiency and causes a permanent overheating of the tube wall. As a result of overheating at the site, the intercrystalline cracks leading to the bursting of the tube are developing. The secondary problem of the growth of oxide layer thickness is so-called exfoliation. For non-destructive evaluation of the thickness of the oxide layer directly at the power station, ultrasonic method (UT) can be used with a high frequency probe. In order to verify the accuracy of the measurement and the qualification of the ultrasonic testing methodology, light and Scanning Electron Microscopy (SEM) was used on specimens that were removed from the super-heater after the UT measurement. The standard longitudinal cut surface imaging in BackScatter Electrons (BSE) and Energy Dispersive Spectroscopy (EDS) analysis for accurate thickness determination with the chemical composition of the layer confirmed the accuracy of the UT measurement.

IoT Communications With <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math> </inline-formula>-PSK Modulated Ambient Backscatter: Algorithm, Analysis, and Implementation

Ambient backscatter (AB), making use of both energy harvesting and backscattering, has recently become a promising solution to communications among low-power devices and demonstrates its potential application in the Internet of Things. Existing AB systems adopt two-state amplitude shift keying or phase shift keying (PSK), where data are transmitted at the rate of one bit per symbol period. To increase the data rate, we investigate the high-order modulation where ${M}$ -PSK is employed for backscattering. We derive the optimal multilevel energy detector and compute the closed-form symbol error rate. To show the realizability of the proposed design, we build a 4PSK-AB hardware prototype, in which the selection of load impedance is discussed with the aid of phasor diagram illustration. The hardware prototype can achieve the date rate of 20 kb/s. Besides, higher date rate is achievable for 98.7% of the time compared with binary AB communications, and the mean number of distinguishable symbols is 3.66.

Microstructure characteristics and fractal analysis of 3D-printed sandstone using micro-CT and SEM-EDS

Replicating sedimentary rocks using three-dimensional (3D) printing can support routine reservoir rock analysis in petrophysical and geomechanical experiments, which is done limited in scope due to lack of suitable printing materials and achievable resolution. Following our previous studies on gypsum powder with binder, a new printing material, silica sand, is used and characterized in this study to demonstrate the microstructure and its similarity to Berea Sandstone. Binder jetting printing system was specifically utilized to bond silica sand particles to create intact cylindrical samples without digital porous model as input. Created samples were first scanned by Backscattered Scanning Electron Microscope (BS-SEM) and Energy Dispersive Spectroscopy (EDS) to identify the particles, the packing mode and cement (binder). Next, micro-computed tomography (CT) was used to determine the microstructure of the samples, including the size and the shape of both particles and pores, in the 3D space. In addition, anisotropy that was found to originate from the pore structures was quantified by comparing the characteristics of pores in different directions. Fractal dimensions from different sample sizes, 6 mm and 12 mm in diameter, were also calculated for pore structure analysis in order to illustrate the effect of sample size on pore heterogeneity in 3D printed samples with silica. The results demonstrated the feasibility of substituting 3D-printed sandstones for natural rocks regarding pore structures for experimental validation of petrophysical models.