Values Of Layer Thickness Research Articles

Optimizing Process Parameters on the LGP Molding Stamper Through the Taguchi Method

The light guide plate (LGP) is a very important component of the backlight module; however, the electroforming process parameters for making LGP molding stampers are often based on accumulated experience and trial and error, which does not ensure that the set parameters are the best factor level combination and often results in increased manufacturing costs and product defect rates. In this article, eight factors, including boric acid concentration, pH value, temperature, current density, consistency of nickel ion, cathode size, anode size, and stirring speed, were selected by cause-and-effect analysis. Next, the Taguchi method was used to obtain the optimal process parameters in the electroforming process by the minimum number of experiments of the L18 orthogonal array. Finally, through actual process verification, in addition to meeting the target value of the nickel layer thickness of the LGP molding stampers, while improving the surface roughness, dot uniformity, and stress, the accuracy and process robustness are obtained.

Anthropometrische Messungen in der NAKO Gesundheitsstudie \u2013 mehr als nur Gr\xf6\xdfe und Gewicht

ZusammenfassungÜbergewicht und Adipositas sind bedeutende Risikofaktoren für verschiedene Erkrankungen. Als Maß zu ihrer Bestimmung wurde in früheren Studien meist nur der Body-Mass-Index (BMI) verwendet. Der BMI ist allerdings ein Marker, der den Einfluss auf das Krankheitsrisiko nur unzureichend erfasst. In groß angelegten, bevölkerungsbasierten Studien besteht daher ein vordringlicher Bedarf, verbesserte Messmethoden der Körperzusammensetzung und -fettverteilung einzusetzen.Der vorliegende Beitrag stellt die in der NAKO (Nationale Kohorte) Gesundheitsstudie eingesetzten Messverfahren zur Beschreibung von Körperzusammensetzung und -fettverteilung und die ersten deskriptiven Ergebnisse vor. Diese beziehen sich auf die Daten zur Halbzeit der Basiserhebung, welche 101.817 Teilnehmende einschließt, die in 18 Studienzentren in Deutschland zwischen März 2014 und März 2017 untersucht worden sind. Die anthropometrischen Messungen umfassten Körpergewicht, Körpergröße und -umfänge, bioelektrische Impedanzanalyse (BIA), Sonographie des Abdominalfettes, 3‑D-Bodyscanner und Magnetresonanztomographie.Die Analyse des BMI zeigte, dass 46,2 % der Männer sowie 29,7 % der Frauen übergewichtig und 23,5 % der Männer und 21,2 % der Frauen adipös waren. Frauen wiesen im Mittel in fast allen Altersgruppen eine höhere Schichtdicke an subkutanem Fettgewebe auf als Männer. Die mittlere Schichtdicke des viszeralen Fettgewebes lag hingegen bei den Männern in allen Altersgruppen über den Werten der Frauen und stieg bei beiden Geschlechtern über die Altersgruppen kontinuierlich an.Die umfassenden Daten über die Körperfettverteilung und -zusammensetzung ermöglichen es zukünftig, den Einfluss von Übergewicht und Adipositas auf die Entstehung von chronischen Erkrankungen im Detail zu analysieren.

Glaciation and Permafrost Dynamics on the Antarctic Peninsula in the 21st Century

The results of mass balance observations of the ice dome and measurements of the active layer thickness on the Fildes Peninsula, King George (Waterloo) Island, Western Antarctica are presented for the period of 2007 to 2019. The dynamics of the main meteorological parameters affecting the active layer thickness is determined. The numerical experiments based on the mathematical model are performed to determine the effects of various parameters on the active layer thickness. The calculated and measured values of the active layer thickness are compared. The thermal instability of permafrost in the study area in some years with high (above the means) summer air temperature is demonstrated. The climate cooling which started in the region in the recent years has increased the number of years with the positive ice mass balance. However, the positive ice mass balance has not yet become a dominant factor against a background of the negative balance in the previous years.

Threshold conditions for thermocapillary transition to deep penetration mode in selective laser melting of metal powder bed

The keyhole mode of selective laser melting (SLM) of metal powder bed in additive technology is characterized by an intensive hydrodynamic process in a thin molten layer. Such a mode is widely used also in laser and electron beam welding indicating the similarity of hydrodynamic processes in these technologies despite a significant difference of operating parameters. The threshold conditions of thermocapillary keyhole mode transition for various metals (Cu, Fe, Ti) in a wide range of beam parameters used for selective laser melting of metal powder layer and laser welding are investigated. The condition of threshold for thermocapillary transition into keyhole mode by sticking of viscous layer to the solid boundary is formulated. The fulfillment of this condition is confirmed by the convergence of estimated values of the viscous layer thickness and the molten layer depth during the transition to a keyhole mode. Analytical estimates of keyhole threshold and comparisons with experimental values of beam power and spot size corresponding to the transition in keyhole mode for SLM processes and laser welding are presented. The correlation of these values confirms the thermocapillary mechanism of cavity formation and the similarity of hydrodynamic processes in laser welding and SLM processing in keyhole mode at wide range of operating parameters.

Layer-by-Layer Printing of Photopolymers in 3D: How Weak is the Interface?

Additive manufacturing or, as also called, three-dimensional (3D) printing is considered as a game-changer in replacing traditional processing methods in numerous applications; yet, it has one intrinsic potential weakness related to bonding of layers formed during the printing process. Prior to finding solutions for improvement, a thorough quantitative understanding of the mechanical properties of the interface is needed. Here, a quantitative analysis of the nanomechanical properties in 3D printed photopolymers formed by digital light processing (DLP) stereolithography (SLA) is shown. Mapping of the contact Young’s modulus across the layered structure is performed by atomic force microscopy (AFM) with a submicrometer resolution. The peakforce quantitative nanomechanical mapping (PF-QNM) mode was employed in the AFM experiments. The layered specimens were obtained from an acrylate-based resin (PR48, Autodesk), containing also a light-absorbing dye. We observed local depressions with values up to 30% of the maximum stiffness at the interface between the consecutively deposited layers, indicating local depletion of molecular cross-link density. The thickness values of the interfacial layers were approximately 11 μm, which corresponds to ∼22% of the total layer thickness (50 μm). We attribute this to heterogeneities of the photopolymerization reaction, related to (1) atmospheric oxygen inhibition and (2) molecular diffusion across the interface. Additionally, a pronounced stiffness decay was observed across each individual layer with a skewed profile. This behavior was rationalized by a spatial variation of the polymer cross-link density related to the variations of light absorption within the layers. This is caused by the presence of light absorbers in the printed material, resulting in a spatial decay of light intensity during photopolymerization.

Diffusion layer thickness in turbulent flow

Average thickness of diffusive layers in a turbulent flow is described using an idea of Lagrangian meso-scale element convected by mean flow and large scale turbulence. This idea enables a formulation of a simple model for the diffusive layer thickness assuming that its evolution is determined by the diffusive growth and two components, compressive normal and tangential, of the turbulent strain rate tensor. Analysis of the possible effects of the folding action of the turbulence leads to the conclusion that the folding becomes significant only at the scales far superior to the considered dimensions of the meso-scale elements, thus it may be neglected in the present formulation. The evolution equation for the meso-scale element thickness is derived and put to test against experiments conducted in plane and round jets. The model proved capable of producing, using the same values of two model constants, values of the diffusive layer thickness in good qualitative agreement with the measurements.While the present numerical simulations of the turbulent jets are made using very simple, perhaps simplistic, flow and turbulence description, they nonetheless allow a fairly accurate estimation of turbulence microscales at different locations in a jet. It turns out that neither Kolmogorov nor Taylor scale provides a good universal reference scale for the diffusive layer thickness and it is local turbulence conditions and history of the meso-scale element determining the latter.

Growth kinetics of Fe2B layers formed on the AISI 4150 steel by different approaches

In the present work, the AISI 4150 steel has been pack-borided in the temperature range of 1123-1273 K for a treatmenttime of 2 to 8 h. The mixture of powders containing 20% B4C, 10% KBF4 and 70% SiC has been used for producing a singleboride layer (Fe2B) at the surface of AISI 4150 steel. The presence of Fe2B phase has been confirmed by XRD analysis.The SEM observations have been done to investigate the morphology of boride layers and measure their thicknesses.The cohesion of boride layers has been evaluated by using the Daimler-Benz Rockwell-C indentation technique.The borided sample at 1173 K for 8 h has shown a best cohesion of boride layer to the substrate in comparison to the sampletreated at 1173 K during 2 h. Kinetically, different approaches have been used to estimate the boron diffusion coefficients inthe Fe2B layers and to predict the value of Fe2B layer thickness obtained at 1253 K for a treatment time of 2.5 h. Theestimated values of activation energies for boron diffusion in AISI 4150 steel have been in the range of 193.45 to 199.74 kJmol-1. These values of activation energies have been depended on the diffusion models used. In addition, a good agreementhas been observed between the experimental value of Fe2B layer thickness obtained at 1253 K for 2.5 h with the predictedvalues from these different diffusion models.

Study on the Limit Value of Safety Overburden Layer Thickness of Large-Span Bias Tunnel

The number of mountain tunnels continues to increase, the explosive demand for traffic increases, and large-span bias tunnels are increasingly appearing in actual projects. Large-span biased tunnels can cause uneven lining stress, and unreasonable thickness of the soil can cause damage to the lining. This paper relies on the Beijing-Hong Kong-Macao Expressway Guangle Expressway. It adopts three construction methods, namely, double-wall method, three-step method and CRD method. At the same time, based on different soil thickness research, it is considered in 1:1, 1:2, 1: 3 Three kinds of slope effects, through the analysis of finite element numerical simulation results, the thickness limits of large-span bias tunnels under different slopes are given. The results show that the tunnel lining is under pressure within the thickness limit of the overburden. If it is too thin, it will cause the lining to be pulled and affect the stability of the tunnel. If it is too thick, it will increase the construction cost and waste. Therefore, the research on the thickness limit of large-span biased soil has a great guiding significance for design and construction.

Comprehensive Analysis of CuIn<sub>1-x</sub>Ga<sub>x</sub>Se<sub>2</sub> Based Solar Cells with Zn<sub>1-y</sub>Mg<sub>y</sub>O Buffer Layer

The development of cadmium-free CIGS solar cells with high conversion efficiency is crucial due to the toxicity of cadmium. Zinc-based buffer layers seem to be the most promising. In this paper, a numerical analysis using SCAPS-1D software was used to explore the Zn(Mg,O) layer as an alternative to the toxic CdS layer. The effect of several properties such as thickness, doping, Mg concentration of the Zn(Mg,O) layer on the current-voltage parameters was explored and their optimal values were proposed. The simulation results reveal that the optimal value of the ZMO layer thickness is approximately 40 nm, the doping at 1017 cm-3 and an Mg composition between 0.15 and 0.2. In addition, the effect of Gallium (Ga) content in the absorber as well as the Zn(Mg,O)/CIGS interface properties on the solar cell’s performance was examined. The results show that contrary to the CdS buffer layer, the best electrical characteristics of the ZMO/CIGS heterojunction are obtained using a Ga-content equal to 0.4 and high interface defect density or unfavorable band alignment may be the causes of poor performances of Zn(Mg,O)/CIGS solar cells in the case of low and high Mg-contents.

Картографирование закономерностей распространения и современных условий мерзлотных ландшафтов Якутии

Digital thematic maps of the modern condition of permafrost landscapes of Yakutia on a scale of 1:1 500 000 have been compiled. A quantitative analysis of the patterns of their spatial distribution was carried out, the differentiation of permafrost landscapes by geocryological characteristics was made, and the areas that are most vulnerable to modern climate change and anthropogenic impacts were identified. The analysis of a series of digital thematic maps of the modern condition of permafrost landscapes in Yakutia showed that 34% of the total territory is occupied by landscapes with soil temperatures from −2 to −4 °C, the least common high-temperature permafrost landscapes (from 0 to −2 °C) – about 4% of the territory. Landscapes with active layer thickness values of about 1 m are spread over 36% of the territory, which is the highest indicator. Insignificant territories (up to 3%) are occupied by landscapes with active layer thickness of up to 3 and 3,5 m. The most widespread landscapes are those with low-ice deposits (less than 0,2) – 38,7%, and landscapes with heavy-ice deposits (more than 0,4) occupy 31%. The most dangerous process is thermokarst, which occurs in the interalassic and slightly drained types of terrain. Key words: permafrost landscape, temperature of soils, ice content of deposits, cryogenic processes, digital maps, GIS model.

Topographic correlation between multifocal electroretinography, microperimetry, and spectral-domain optical coherence tomography of the macula in patients with birdshot chorioretinopathy

PurposeTo correlate the findings of retinal function with multifocal electroretinogram (mfERG), microperimetry (MP), and structural assessments with spectral-domain optical coherence tomography (SD-OCT) in topographically corresponding areas of the macula of patients with birdshot chorioretinopathy (BSCR).MethodsPatients diagnosed with BSCR by clinical and imaging findings were included in the study. The mfERG was performed using 61 hexagon stimulus patterns grouped into 5 rings (Diagnosys Inc., USA). Individual responses [N1-P1 amplitudes in nanovolt (NV)/degree2 and P1 implicit time in milliseconds (msec)] for each hexagon in the central 3 rings (R1, 0°–2.3°; R2,2.3°–7.7°; and R3, 7.7°–12°) were obtained (19 hexagons). MP examination consisted of Polar 3–12° test with 28 points in 3 concentric rings with diameters of approximately 2.3°, 6.6°, and 11.1° from the foveal center. SD-OCT was performed using macular scans of 20° × 20°. The retinal sensitivity values on MP and thickness values of retinal layers were correlated with the responses on the mfERG for each topographically correlated hexagon.ResultsSixteen eyes of eight patients were included in the study (mean age, 59.87 ± 10.01 years; range, 41–73 years). The amplitudes and the implicit times on mfERG and retinal sensitivities on MP were decreased for each of the 19 hexagons. Considering retinotopically matched points, there was correlation between the retinal sensitivities and mfERG implicit times and response amplitudes in all three rings. The thickness of the retinal pigment epithelium showed modest correlation with the mfERG parameters (ρ = 0.29; p = 0.04). The structural changes on SD-OCT, such as IS-OS disruption, were associated with changes in the mfERG trace arrays.ConclusionsThe structural and functional assessments in retinae of eyes with BSCR suggest that each imaging tool may be capturing unique aspects of retinal dysfunction. Multimodal imaging may allow detailed analyses of retinal damage at various corresponding loci. These findings are important when considering the use of these techniques in BSCR.

Enhanced Adsorptive Desulfurization Using Mongolian Anthracite-Based Activated Carbon.

This study reports usage of Mongolian anthracite-based porous activated carbons (PMACs), namely, PMAC 1/3 and PMAC 1/4 for model diesel fuel desulfurization, having 500 ppmw of dibenzothiophene (DBT) in n-heptane. Further, the effects of contact time, adsorbent dosage, and temperature on the adsorption capacity were studied systematically. The experimental adsorption isotherm results were well represented by the Sips isotherm for PMAC 1/3 and the dual site Langmuir isotherm for PMAC 1/4. The maximum DBT adsorption by PMAC 1/3 and PMAC 1/4 were 99.7 and 95.7%, respectively. The kinetics for the adsorption of DBT on PMACs follows the pseudo second order behavior. The Weber–Morris plot shows the multilinearity over the entire time range, suggesting that both the surface and pore diffusions control the adsorption. The values of boundary layer thickness for PMAC 1/4 and PMAC 1/3 were found to be 3.183 and 1.643, respectively. Thus, PMAC 1/4 possesses more surface diffusion control than PMAC 1/3. The changes in Gibbs free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) are negative, which confirms that the studied process is spontaneous and exothermic and possesses less randomness at the interface. Based on the Sips isotherm, single-stage batch-adsorber design was prepared for the adsorption of DBT onto PMAC 1/3.

Prediction of Failure Pressure in Pipelines with Localized Defects Repaired by Composite Patches

In recent years, fibrous composite materials have been used to repair pipelines in combination with commonly employed standards such as ASTM B31G and ASTM PCC2. Reinforcement and repair of pipelines without interruption are the advantages of these new methods. Pipe repair by composite patches with considering various types of surface damages and crack has been investigated in many previous works. In the present paper, a comprehensive model has been developed to predict the critical pressure for several defect types in static pressure loading condition using the ABAQUS finite element software. The effect of various defect patterns in API X65 Grade steel pipes is investigated by a ductile damage criterion. The obtained results are assessed using available experimental data. The first ply failure theory is employed to predict failure in composite patches. The effects of boundary conditions are considered using a semi-infinite element. The results generated from finite element simulations are compared with those from ASTM PCC2 standard. Moreover, the required minimum patch thickness for different live internal pressures is proposed. The extended finite element method is also applied to study the effect of patch layer thickness on crack propagation. The effect of initial crack angle on the critical internal pressure with and without patch is investigated too. The results indicate that the z symmetric boundary conditions are appropriate for pipelines. The estimation of the burst pressure using a ductile damage criterion is shown to be in good agreement with experimental data and ASME B31G. Furthermore, the estimated values for patch layer thickness obtained by the present approach agree well with ASME PCC2 standard. The obtained results also clearly indicate that using composite patches has no considerable influence on prevention of crack propagation.

Hardware Factors Influencing Strength of Parts Obtained by Fused Filament Fabrication.

The current paper investigates the influence of the hardware setup and parameters of a 3D printing process on the resulting sample strength obtained through fused filament fabrication (FFF) technology. Three-point bending was chosen as the strength measure for samples printed with the long side oriented along the Z-axis. A single CAD model was converted into NC-programs through the same slicing software to be run on five different desktop FFF 3D printers with filament of the same brand and color. For all the printers, the same ranges of layer thickness values from 0.1 to 0.3 mm and feed rates from 25 to 75 mm/s were planned to be varied. The first four machines considered in the study were off the shelf devices available on the market, and the fifth was a quick prototype of a desktop machine design based on the analysis of pros and cons of the four machines considered. The results of the study show that the hardware setup of a desktop 3D printer can drastically change the influence of basic technological parameters such as feed rate and layer thickness on the interlayer bonding. This means that many of the conclusions drawn from previous studies connecting the technological parameters of the FFF process with the mechanical performance of parts and samples may only be correct for specific hardware setups.

The influence of basalt fabrics modifications on their resistance to contact heat and comfort properties

Purpose The purpose of this paper is to present the influence of modifying the fabric surface made from basalt fibers by the magnetron sputtering of chromium and aluminum layers on its resistance to contact heat and comfort properties. Design/methodology/approach In order to modify the surface of basalt fabric, the process of physical deposition from the gas phase was used. It relies on creating a coating on a selected substrate by applying physical atoms, molecules or ions of specific chemical compounds. The trial of modification was carried out using the magnetron sputtering method due to the material versatility, application flexibility and ability to apply layers on substrates of various sizes and properties. Findings The findings obtained regarding the heat resistance to contact heat and thermal insulation (comfort) properties show different values depending on the type of metal deposited and the thickness of coating layer. It was found that the modification of basalt fabric surface at the micrometer level changes the tested parameters. Research limitations/implications This paper presents the results of resistance to contact heat and thermal insulation properties only for the twill fabric made of basalt fiber. The surface modification of fabric was carried out using the chromium and aluminum of two values of layer thickness (1 and 5 µm). Originality/value So far, no tests have been carried out to modify the surface of fabric made from basalt fiber yarns using the magnetron sputtering method. In addition, it has not been studied, how the modification of fabric affects its resistance to contact heat and thermophysiological properties.

Retinal Degeneration After First-Ever Optic Neuritis Helps Differentiate Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder.

Objective: Differentiation between neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) in the early phase is challenging but crucial for treatment and prognosis.Methods: We performed a prospective cross-sectional study to discriminate NMOSD from MS by evaluating retinal degeneration in optical coherence tomography (OCT) after a first-ever optic neuritis (ON) episode. Seventy-three NMOSD patients and 38 MS patients with ON at least 3 months prior were assessed by OCT, best-corrected visual acuity (VA), and 2.5% low-contrast VA. Multivariate linear regression models were used for comparisons. Receiver operating characteristic curves and Youden index were used for determining the discriminative value of retinal nerve fiber layer thickness (RNFL) and VA in distinguishing NMOSD from MS.Results: Among eyes with retinal degeneration after a first-ever ON episode (n = 93), NMOSD eyes (n = 60) presented thinner RNFL (p < 0.001) and worsened VA (p < 0.001) relative to MS eyes (n = 33). Furthermore, a RNFL thinner than 78.9 μm had a specificity of 93.9% for NMOSD; combined with a VA of <0.4 decimal, these characteristics provided 100% specificity for NMOSD.Conclusions: The first-ever ON eyes showed more severe retina degeneration in patients with NMOSD than MS, which could establish a cut-off of RNFL thickness and VA to distinguish NMOSD from MS in the early phase.

Self-excited oscillation study in grille-cavity flow on floating nuclear power platform

In order to investigate the self-excited oscillation characteristic of flow past the inlet and outlet of cooling water systems on floating nuclear power platform, a numerical study in grille-cavity flow with suction and drain is carried out. A back pressure condition is set on the side wall of the cavity to simulate the suction and drain conditions. By varying the incoming flow boundary layer thickness and back pressure value, the self-excited oscillation characteristic in grille-cavity flow with suction and drain is studied. As calculations show, the boundary layer thickness has little influence on the oscillation frequency. The strength of self-excited oscillations gradually decreases with the decrease of back pressure, but the frequency does not change much. When the back pressure reduces to a critical value, the self-excited oscillation phenomenon disappears finally.

Influence of Process Parameters on Tensile Strength of Additive Manufactured PLA Parts using Taguchi Method

Influence of layer thickness nozzle temperature and angle on tensile strength of PLA fabricated with FDM (FFF) was experimentally investigated. Polylactic Acid (PLA) is a semi-crystalline and bio-friendly thermoplastic polymer has identified as important material in different applications due to its mechanical characteristics. Fused Deposition Modeling (FDM) is a one of the proved technology in Fused Filament Fabrication (FFF) technique in additive manufacturing process. In present investigation different specimens were fabricated using FDM technique with different layer height and different layer angles for finding influence of these manufacturing parameters on tensile strength of the specimen. Specimens were fabricated and tested as per ASTM D638 standard. It is clearly observed that tensile strength is more for +450/-450 layer angle than the +00/-00 layer angle for a given layer height(h=0.10 mm, h=0.15mm and h=0.20mm).The TAGUCHI analysis is carried with nozzle temperature, layer thickness and angle finding optimal values. It has been observed that, the optimal parameter is angle, which is equal to 300.the ANOVA variation of angle layer with tensile strength has been observed that 18.10-31.90.

Combination of spectroscopic ellipsometry and spectroscopic reflectometry with including light scattering in the optical characterization of randomly rough silicon surfaces covered by native oxide layers

A combined method of spectroscopic ellipsometry and spectroscopic reflectometry is employed for the optical characterization of randomly rough surfaces of silicon single crystal covered with very thin native oxide layers within spectral range 197–1240 nm (1.0–6.3 eV). It is shown that random roughness of the samples of this system exhibits a wide interval of spatial frequencies so that the Rayleigh–Rice theory, scalar diffraction theory for coherent light and scalar diffraction theory with including light scattering must be used to achieve good fits of experimental data. The ellipsometric data are compatible with the Rayleigh–Rice theory within the entire spectral range while the reflectometric data must be processed separately within two sub-ranges using two different theoretical approaches. In one of the sub-ranges the combination of Rayleigh–Rice theory and scalar diffraction theory for coherent light is utilized for obtaining good fits of the corresponding experimental data of reflectance. Within the latter sub-range the scalar diffraction theory including the influence of light scattering on reflectance enables us to achieve good fits. Further, it is shown that using this combined method the values of basic roughness parameters, i.e. the rms values of heights, autocorrelation lengths and rms values of slopes of roughness irregularities, can be determined together with thickness values of the native oxide layers. A comparison of the results achieved optically with those determined by atomic force microscopy is performed. The assessment of efficiency of spectroscopic ellipsometry and spectroscopic reflectometry in characterizing random roughness with the wide interval of spatial frequencies is also presented.

Numerical Simulation Study of Heavy Oil Production by Using In-Situ Combustion

An in-situ combustion method is an effective method to enhance oil recovery with high economic recovery rate, low risk, fast promotion and application speed. Currently, in-situ combustion technique is regarded as the last feasible thermal recovery technology to replace steam injection in the exploitation of bitumen sands and heavy oil reservoirs. However, the oil-discharging mechanism during the in-situ combustion process is still not clearly understood. In this paper, the in-situ combustion process has been numerically simulated based on the Du 66 block. The effect of production parameters (huff and puff rounds, air injection speed, and air injection temperature) and geological parameters (bottom water thickness, stratigraphic layering, permeability ratio, and formation thickness) on the heavy oil recovery have been comprehensively analyzed. Results show that the flooding efficiency is positively correlated with the thickness of the bottom water, and negatively correlated with the formation heterogeneity. There exist optimum values for the oil layer thickness, huff and puff rounds, and air injection speed. And the effect of air injection temperature is not significant. The results of this paper can contribute to the understanding of mechanisms during in-situ combustion and the better production design for heavy oil reservoirs.