Low Inclination Research Articles

The general applicability of self-similar solutions for thermal disc winds

ABSTRACT Thermal disc winds occur in many contexts and may be particularly important to the secular evolution and dispersal of protoplanetary discs heated by high energy radiation from their central star. In this paper, we generalize previous models of self-similar thermal winds – which have self-consistent morphology and variation of flow variables – to the case of launch from an elevated base and to non-isothermal conditions. These solutions are well-reproduced by hydrodynamic simulations, in which, as in the case of isothermal winds launched from the midplane, we find winds launch at the maximum Mach number for which the streamline solutions extend to infinity without encountering a singularity. We explain this behaviour based on the fact that lower Mach number solutions do not fill the spatial domain. We also show that hydrodynamic simulations reflect the corresponding self-similar models across a range of conditions appropriate to photoevaporating protoplanetary discs, even when gravity, centrifugal forces, or changes in the density gradient mean the problem is not inherently scale free. Of all the parameters varied, the elevation of the wind base affected the launch velocity and flow morphology most strongly, with temperature gradients causing only minor differences. We explore how launching from an elevated base affects Ne ii line profiles from winds, finding it increases (reduces) the full width at half maximum (FWHM) of the line at low (high) inclination to the line of sight compared with models launched from the disc midplane and thus weakens the dependence of the FWHM on inclination.

Computational Flow Analysis on a Real Scale Run-of-River Archimedes Screw Turbine with a High Incline Angle

The Archimedes screw turbine (AST) is the most sustainable mini-hydropower extraction method that offers number of economic, social, and environmental advantages. Nowadays, many researchers are interested in AST development as it is considered a new technology. Currently, a lot of researchers are conducting experimental testing of the screws, comparing their reliability with computational fluid dynamic (CFD) analyses. Almost all of them are lab-scale testing models that claiming an average 80% efficiency for low pitch angles. In the case of a real site with a small inclination angle, the length of the screw is large enough to cause severe problems, specially related to bending of the screw. Therefore, this research was conducted to analyze the CFD flow field in a real site-scale AST with the maximum possible inclination of 45 degrees. In addition, the design was done without the upper and lower reservoir as it was conceived as a run-of-river flow system. The simulated real scale AST result showed a maximum efficiency of around 82% for a 5.2 m hydraulic head and 0.232 m3/s discharge. Many researchers claim above 80% efficiency for low inclination angle ASTs with reservoirs. This CFD study indicates that even higher inclination angle ASTs can achieve 80% efficiency in run-of-river; real-scale applications.

The great Chinese fireball of December 22, 2020

On December 22, 2020, at about 23h 23m 33s UTC a very bright fireball was seen in the sky of southeastern China. The fireball lasted for several seconds and ended with an atmospheric explosion that was detected by US surveillance satellites. According to CNEOS’s data, the fireball moved with a mean speed of 13.6 km/s and exploded at an altitude of about 35.5 km (Lat. 31.9^{circ } N; Long. 96.2^{circ } E). In this paper we estimate the atmospheric trajectory, the heliocentric orbit and the strewn fields for different mass/section ratio of the fragments. The trajectory was about from north to south and with low inclination (5^{circ } pm 2^{circ }) with respect to the local surface. The explosion height appears consistent with a fragmented rocky body, and the heliocentric orbit supports an asteroidal origin. The probable strewn field extends between two points with coordinates (+31.3^circ N; 96.3^circ E) and (+30.3^circ N; 96.5^circ E), for a total area of about 4000 text {km}^2. This large extension is a direct consequence of the low inclination of the trajectory. Given the unknown uncertainty of the CNEOS’s data, these results should be taken with caution.

Providing real-time bus crowding information for passengers: A novel policy to promote high-frequency transit performance

Bus bunching is of particular concern and undesirable for both operators and passengers in high-frequency transit. In contrast to existing control methods, this paper proposes a novel control policy, namely, providing real-time bus crowding information (BCI) for passengers. It is believed that passengers would spontaneously distribute more evenly among buses and help to prevent bus bunching with the provision of BCI accompanying arrival time information due to the following mechanism. A proportion of passengers would be likely to wait a few more minutes for the next bus when the current bus is crowded and the next bus is more comfortable, and the boarding times of these passengers would make the next bus dwell longer and increase its headway from the previous bus. We formulate bus motion models incorporating passenger boarding choice under BCI to realize the policy in simulation experiments. The results demonstrate that the policy can reduce operation instability by approximately 20% in terms of bus headway and single-trip time. In addition, this policy can significantly reduce the in-vehicle crowdedness experienced by passengers by up to 25% at the cost of small increases in the mean journey time in some cases. The simulation experiments on a holding-controlled route also indicate that the proposed policy is able to coordinate with holding well. A sensitivity analysis further confirms that the policy’s performance is robust even if the passengers have low inclinations to choose the next bus. The policy of providing BCI in this paper is especially effective for bus routes with high passenger demand and may have great application potential in practice.

Variations of the Galactic Cosmic Rays in the Recent Solar Cycles

Abstract In this paper, we study the Galactic cosmic-ray (GCR) variations over the solar cycles 23 and 24, with measurements from NASA’s Advanced Composition Explorer/Cosmic Ray Isotope Spectrometer instrument and the ground-based neutron monitors (NMs). The results show that the maximum GCR intensities of heavy nuclei (5 ≤ Z ≤ 28, 50∼500 MeV nuc−1) at 1 au during the solar minimum in 2019–2020 break their previous records, exceeding those recorded in 1997 and 2009 by ∼25% and ∼6%, respectively, and are at the highest levels since the space age. However, the peak NM count rates are lower than those in late 2009. The difference between GCR intensities and NM count rates still remains to be explained. Furthermore, we find that the GCR modulation environment during the solar minimum P 24/25 are significantly different from previous solar minima in several aspects, including remarkably low sunspot numbers, extremely low inclination of the heliospheric current sheet, rare coronal mass ejections, weak interplanetary magnetic field and turbulence. These changes are conducive to reduce the level of solar modulation, providing a plausible explanation for the record-breaking GCR intensities in interplanetary space.

PROCEDURE OF TENDENCY MAP ON THE BASIS OF GEOGRAPHICAL INFORMATION SYSTEM OF JALILABAD CADASTRY DISTRICT

As the inclination increases, soil erosion and, in general, the process of erosion on the slopes intensifies, the moisture content of the soil and soil-forming rocks decreases, the growth of agricultural crops and pastures weakens, and productivity decreases. Taking all this into account, we have developed a slope map with degrees based on the digital elevation model of the Jalilabad cadastral region (DEM file). Slope study and mapping is one of the key measures to protect soils from erosion as well as to combat erosion. When the slope reaches 3-4°, the washing of the soil is even faster. It is not recommended to plow the fields when the slope is 8-10° and more. From this point of view, as a result of our research, the inclination of the Jalilabad cadastral region has been studied. The lowest inclination range in the study area is 0-20. Low inclination is observed mainly in the plains of Jalilabad cadastral region. As you ascend to the heights, there is an increase in inclination. Taking into account the propensity in agriculture can lead to high yields. Key words: Inclination, Slope, Erosion, Geographic Information System (GIS), ESRI, ArcGis

A fast calculation method for asteroid exploration window based on optimal and sub-optimal two-impulse transfer orbits

For impulse transfers, the solution of two-impulse rendezvous is generally obtained by solving the Lambert orbit problem, and the search for the exploration window of the target celestial body is a two-dimensional optimization based on velocity increment calculation. In order to assess the accessibility and exploration window of large-number asteroids, this paper approximates the transfer orbit from the Earth to the target asteroid as a co-planar two-impulse transfer orbit and gives an effective method. Based on the theory of cotangential transfer orbit, this paper proposes a method to express the transfer orbit with one single variable (the aphelion argument of the transfer orbit, θT), which can also determine the start time of the transfer. After that, the paper combines the two-impulse orbit transfer theory (without considering the rendezvous) with the calculation method of the exploration window (considering the rendezvous), proposing the concept of the rendezvous difference angle εR. εR is defined as the mean anomaly angle difference between the spacecraft and the target object when the spacecraft enters the target orbit. The rendezvous difference angle εR has the same minimum point as the velocity increment in exploration window search, while it can be directly calculated from the transfer orbit and the transfer time. When cotangential transfer orbits are used, εR can be expressed as a function of θT. Taking εR as the optimal target variable, the exploration window search can be simplified to a one-dimensional problem. This method is suitable for the large-scale accessibility calculation for asteroids with low inclinations, so as to quickly determine the accessible target group.

Inclined rotating fixed-bed reactor – Experimental characterization and model-based predictions

The performance of an inclined rotating fixed-bed reactor with concentric inner tube is analyzed for the hydrogenation of α-methylstyrene. In particular, the influences of low to intermediate rotational velocities (0.6–10 rpm), inclination angle (45°–75°) and superficial gas velocity (0.05–0.15 m s−1) on the space–time yield at stratified flow conditions are investigated, which is the most beneficial operation mode. A performance enhancement of up to 20% compared to the upright stationary trickle-bed reactor is obtained for the operating conditions studied experimentally. Here, operating conditions show highest performance at low inclination angles due to the most favourable mass transfer conditions. Additionally, a hybrid model approach comprising a 3D Eulerian-Eulerian model and a 1D heterogeneous continuum model is proposed to predict the space–time yield of the rotating reactor. Simulations show the capability of the model to properly predict the effect of operating conditions and reactor dimensions.

An upper limit for the growth of inner planets?

ABSTRACT The exotic range of known planetary systems has provoked an equally exotic range of physical explanations for their diverse architectures. However, constraining formation processes requires mapping the observed exoplanet population to that which initially formed in the protoplanetary disc. Numerous results suggest that (internal or external) dynamical perturbation alters the architectures of some exoplanetary systems. Isolating planets that have evolved without any perturbation can help constrain formation processes. We consider the Kepler multiples, which have low mutual inclinations and are unlikely to have been dynamically perturbed. We apply an adaption of previous modelling efforts, accounting for the two-dimensionality of the radius ($R_\mathrm{pl} =0.3\!-\!20\, R_\oplus$) and period (Porb = 0.5–730 d) distribution. We find that an upper limit in planet mass of the form $M_\mathrm{lim} \propto a_\mathrm{pl}^{\beta } \exp (-a_\mathrm{in}/a_\mathrm{pl})$, for semimajor axis apl and a broad range of ain and β, can reproduce a distribution of Porb, Rpl that is indistinguishable from the observed distribution by our comparison metric. The index is consistent with β = 1.5, expected if growth is limited by accretion within the Hill radius. This model is favoured over models assuming a separable PDF in Porb, Rpl. The limit, extrapolated to longer periods, is coincident with the orbits of RV-discovered planets (apl > 0.2 au, $M_\mathrm{pl}\gt 1\, M_\mathrm{J}$) around recently identified low density host stars, hinting at isolation mass limited growth. We discuss the necessary circumstances for a coincidental age-related bias as the origin of this result; such a bias is possible but unlikely. We conclude that, in light of the evidence suggesting that some planetary systems have been dynamically perturbed, simple models for planet growth during the formation stage are worth revisiting.

Effect of surface geometry on laser powder bed fusion defects

Laser Powder Bed Fusion (L-PBF) is an additive manufacturing (AM) technology which has enabled the fabrication of highly complex structures and components. A major challenge in producing these high complexity structures is predicting where defects are likely to occur, and how severe those defects will be. In this study build geometry is linked to manufacturability, using quantifiable AM defects and metrics. This was achieved by fabricating a variety of unsupported, thin-walled samples with different curvatures using Al-10Si-Mg alloy. A combination of X-Ray computed tomographic (XCT) and digital stereomicroscopy were used to capturing positional data about the total geometric error, surface quality and roughness metrics (Ra and Rz). This dataset was used to create empirical model which predicts geometric error based on the local curvature, orientation and thickness of the computer-aided-design (CAD) geometry. Local inclination angle was observed to have the strongest effect on manufacturability, heavily impacting the geometric error and surface quality metrics. Sample shape defined by curvature was observed to be a secondary factor, which became important in areas of low inclination angle. The empirical model was applied in a case study of a cellular structure, the double gyroid, which successfully identified problematic regions of the structure. The approach of linking fundamental geometry features to defects shown in this study provides additional guidance in design for AM, with potential applications in topology optimisation, optimising part orientation to reduce support, and for design of other intricate components such as the internal conduits of heat exchange devices, where supports are not feasible to use.

Spatial and temporal variability of deep convective clouds over the tropics using multi-year Megha - Tropiques – Sondeur Atmosphérique du Profil d’Humidité Intertropicale par Radiométrie (SAPHIR) observations

ABSTRACT Multi-year seasonal mean diurnal variation of the occurrence frequency of Deep Convective Clouds (DCCs) over the tropical belt for various climatic regions including land and ocean are studied, using Level-1 brightness temperature () data from Sondeur Atmosphérique du Profil d’Humidité Intertropicale par Radiométrie (SAPHIR) payload, aboard the Megha-Tropiques (MT) satellite for the period 2011 to 2018. The low inclination orbit of MT which provides the measurements at different local times makes the study of the diurnal cycle of DCCs possible from a single platform over the entire tropics. The spatial and temporal distribution of DCCs are derived for different seasons including measurements at all possible local time (LT) unlike measurements from a payload aboard polar-orbiting satellites. The seasonal variation of DCCs is in concurrence with the position of sun with maximum occurrence frequency in the summer months of the respective hemisphere. The largest occurrence of DCCs are found over the west Pacific and the northeast Bay of Bengal with a maximum occurrence frequency of around 4.0% during Northern Hemispheric summer. Central African landmasses, the South Pacific Convergence Zone, and the Amazon region also show a higher occurrence during their summer seasons. From the occurrence frequency maps, different regions are identified to estimate the seasonal mean diurnal variation of those regions. Over the continental regions, convective activity peaks during 15:00 to 18:00 LT and over the open ocean it peaks during 00:00 to 06:00 LT. Similarly, the convective activity is minimum over the oceanic region during 12:00 to 18:00 LT and over the land during 06:00 to 12:00 LT. The specific features associated with the distribution of DCC such as double Inter-Tropical Convergence Zone (ITCZ), the mean zonal diurnal variation of DCCs, the effect of El-Niño, the role of surface temperature and surface wind convergence on the occurrence of DCC are also presented.

Roughness and Near-Surface Porosity of Unsupported Overhangs Produced by High-Speed Laser Powder Bed Fusion.

Laser powder bed fusion (LPBF) is a promising technology that requires further work to improve productivity to be adopted more widely. One possible approach is to increase the laser power and scan speed. A customized high-speed and high-power LPBF system has been developed for this purpose. The current study investigated the surface roughness and near-surface porosity as a result of unsupported overhangs at varying inclination angles and orientations during the manufacturing of Ti6Al4V parts with this custom high-speed and high-power LPBF system. It is known that surface roughness and porosity are among the main drawbacks for parts manufactured by LPBF, and that supports are required for overhang regions with low inclination angles relative to the powder bed, typically in commercial LPBF systems requiring supports for regions with inclination angles less than 45°. However, the appropriate inclination angles for this custom system with high power and speed requires investigation. In this article, a simple benchmark test artefact with different inclination angles was manufactured in different orientations on the build platform and characterized by X-ray tomography, touch probe roughness meter, optical microscopy, and scanning electron microscopy. The analysis of surface roughness and near-surface porosity at upskin and downskin regions was performed as a function of inclination angle. The results indicate that the high-speed LPBF process produces relatively high roughness in all cases, with different porosity distributions at upskin and downskin areas. Both roughness and porosity vary as a function of inclination angle. Significant warping was observed, depending on build orientation relative to laser scanning direction. These are the first reported results of the detailed surface roughness and porosity characterization of part quality from such a high-speed, high-power LPBF process.

An HST Survey of Protostellar Outflow Cavities: Does Feedback Clear Envelopes?

Abstract We study protostellar envelope and outflow evolution using Hubble Space Telescope NICMOS or WFC3 images of 304 protostars in the Orion molecular clouds. These near-IR images resolve structures in the envelopes delineated by the scattered light of the central protostars with 80 au resolution, and they complement the 1.2 μm to 870 μm spectral energy distributions (SEDs) obtained with the Herschel Orion Protostar Survey program. Based on their 1.60 μm morphologies, we classify the protostars into five categories: nondetections, point sources without nebulosity, bipolar cavity sources, unipolar cavity sources, and irregulars. We find point sources without associated nebulosity are the most numerous, and show through monochromatic Monte Carlo radiative transfer modeling that this morphology occurs when protostars are observed at low inclinations or have low envelope densities. We also find that the morphology is correlated with the SED-determined evolutionary class, with Class 0 protostars more likely to be nondetections, Class I protostars to show cavities, and flat-spectrum protostars to be point sources. Using an edge detection algorithm to trace the projected edges of the cavities, we fit power laws to the resulting cavity shapes, thereby measuring the cavity half-opening angles and power-law exponents. We find no evidence for the growth of outflow cavities as protostars evolve through the Class I protostar phase, in contradiction with previous studies of smaller samples. We conclude that the decline of mass infall with time cannot be explained by the progressive clearing of envelopes by growing outflow cavities. Furthermore, the low star formation efficiency inferred for molecular cores cannot be explained by envelope clearing alone.

Texture of inclined up-facing surfaces in laser powder bed fusion of metals

Considerable surface texture is one of the typical drawbacks of laser powder bed fusion (LPBF). Especially up-facing inclined surfaces suffer from insufficient quality, due to the combination of the staircase effect (also called stair-stepping effect), attached powder particles and elevated edges (edge effect). In this work, the contribution of the edge effect to the topography of up-facing inclined surfaces is investigated in detail for the first time. Moreover, the effect of contour scanning was evaluated on up-facing surfaces over the whole range of inclinations, from horizontal to vertical. The edge effect was found to play a dominant role for surfaces with a low inclination angle, especially when contour scanning is used. A suitable scanning strategy can thus be determined for each surface inclination. In the present study, an optimization of scanning strategy allowed a significant improvement of the inclined surface quality. The arithmetical mean height of the roughness profile Ra could be reduced up to 52% for low inclinations, 20% for high inclinations and 32% for vertical walls.

Accretion disc cooling and narrow absorption lines in the tidal disruption event AT 2019dsg

ABSTRACT We present the results of a large multiwavelength follow-up campaign of the tidal disruption event (TDE) AT 2019dsg, focusing on low to high resolution optical spectroscopy, X-ray, and radio observations. The galaxy hosts a super massive black hole of mass $\rm (5.4\pm 3.2)\times 10^6\, M_\odot$ and careful analysis finds no evidence for the presence of an active galactic nucleus, instead the TDE host galaxy shows narrow optical emission lines that likely arise from star formation activity. The transient is luminous in the X-rays, radio, UV, and optical. The X-ray emission becomes undetected after ∼100 d, and the radio luminosity density starts to decay at frequencies above 5.4 GHz by ∼160 d. Optical emission line signatures of the TDE are present up to ∼200 d after the light-curve peak. The medium to high resolution spectra show traces of absorption lines that we propose originate in the self-gravitating debris streams. At late times, after ∼200 d, narrow Fe lines appear in the spectra. The TDE was previously classified as N-strong, but after careful subtraction of the host galaxy’s stellar contribution, we find no evidence for these N lines in the TDE spectrum, even though O Bowen lines are detected. The observed properties of the X-ray emission are fully consistent with the detection of the inner regions of a cooling accretion disc. The optical and radio properties are consistent with this central engine seen at a low inclination (i.e. seen from the poles).

BG Tri: an example of a low-inclination RW Sex-type nova-like

ABSTRACT We analyse a wealth of optical spectroscopic and photometric observations of the bright (V = 11.9) cataclysmic variable BG Tri. The Gaia DR2 parallax gives a distance d = 334(8) pc to the source, making the object one of the intrinsically brightest nova-like variables seen under a low orbital inclination angle. Time-resolved spectroscopic observations revealed an orbital period of $P_{\rm {orb}}=3.8028(24)$ h. Its spectroscopic characteristics resemble RW Sex and similar nova-like variables. We disentangled the H α emission line into two components, and show that one component forms on the irradiated face of the secondary star. We suggest that the other one originates at a disc outflow area adjacent to the L3 point.

The improvement of BDS Observation Geometry with LEO constellations in Orbit Determination

The ability of low earth orbit (LEO) satellites with space-borne global navigation satellite system (GNSS) to improve the accuracy of GNSS satellite orbit determinations has been demonstrated. In this paper, the ability of LEO satellites to improve the observation geometry in the process of the determination of BeiDou Navigation Satellite System (BDS) satellite orbits is the focus. First, the visible BDS satellite model with ground stations and LEO satellites is derived, and the definition of the position dilution of precision (PDOP) is proposed for assessing the observation geometries of BDS satellite orbit determination. Then, the observation geometry of BDS geosynchronous earth orbit (GEO), inclined geosynchronous satellite orbit (IGSO) and medium earth orbit (MEO) satellites are individually analysed by regional ground stations. By designing LEO satellites with different inclinations, altitudes and right ascensions of ascending nodes (RAANs), the PDOP improvements achieved through combinations with different orbital LEO satellites are calculated. Finally, the PDOP improvements caused by incorporating different numbers of LEO constellations are compared. The results show that LEO satellites can improve the observation geometries of BDS satellites, especially when the monitoring of observation configurations by only ground stations is very poor. The PDOP improvements of BDS GEO satellites caused by LEO satellites are more significant than those of IGSO or MEO satellites; i.e., the improvement percentage of C04 is better than 60%. Generally, LEO satellites with high altitudes are more suitable for PDOP improvements to BDS satellites than are LEO satellites with low altitudes; moreover, LEO satellites with high inclinations are more suitable for PDOP improvements to BDS GEO satellites than LEO satellites with low inclinations are. The influence of the RAAN on the PDOP improvements of IGSO and MEO satellites is relatively larger than its influence on the PDOP improvement of GEO satellites. The PDOP improvement percentage and stability of BDS satellites, especially GEO satellites, increase with the number of incorporated LEO satellites. When incorporating the LEO constellation 16/4/1:1000 km, 70°, the maximum improvements of the GEO and IGSO satellites are above 84% and 77%. The improvements of the GEO, IGSO and MEO satellites are above 81%, 42% and 58% respectively.

A High‐Resolution Paleosecular Variation Record for Marine Isotope Stage 6 From Southeastern Black Sea Sediments

AbstractA full‐vector paleosecular variation (PSV) record (inclination, declination, and relative paleointensity) from the pen‐ultimate glacial (130–180 ka) could be constructed from a total of 12 sediment cores recovered from the Arkhangelsky Ridge in the SE Black Sea. Stacking of the individual partly fragmented records was achieved by a detailed correlation using high‐resolution data records from X‐ray fluorescence scanning, Ca/Ti and K/Ti log‐ratios, as well as magnetic susceptibility. Age constraints are provided by a detailed composite oxygen isotope stratigraphy from three of the cores, correlated to U‐Th‐dated speleothem oxygen isotope records from Hungary and Turkey. The temporal resolution of the stacked paleomagnetic data records is 200 years. Practically, this data set is the first high‐resolution PSV record for SE Europe/SW Asia from marine isotope stage 6, comprising inclination, declination and relative paleointensity. Besides an easterly swing in declination at ∼159 ka and a pronounced intensity low together with low inclinations at ∼148 ka, both not reaching an excursional PSV index of >0.5, the obtained directional variations reflect only normal PSVs, with a PSV index of <0.3.

Unsteady Hemodynamics in Intracranial Aneurysms With Varying Dome Orientations

Abstract Fluid loading within an intracranial aneurysm is difficult to measure but can be related to the shape of the flow passage. The outcome of excessive loading is a fatal hemorrhage, making it necessary for early diagnosis. However, arterial diseases are asymptomatic and clinical assessment is a challenge. A realistic approach to examining the severity of wall loading is from the morphology of the aneurysm itself. Accordingly, this study compares pulsatile flow (Reynolds number Re = 426, Womersley number Wo = 4.7) in three different intracranial aneurysm geometries. Specifically, the spatio-temporal movement of vortices is followed in high aspect ratio aneurysm models whose domes are inclined along with angles of 0, 45, and 90 deg relative to the plane of the parent artery. The study is based on finite volume simulation of unsteady three-dimensional flow while a limited set of particle image velocimetry experiments have been carried out. Within a pulsatile cycle, an increase in inclination (0–90 deg) is seen to shift the point of impingement from the distal end toward the aneurysmal apex. This change in flow pattern strengthens helicity, drifts vortex cores, enhances spatial displacement of the vortex, and generates skewed Dean's vortices on transverse planes. Patches of wall shear stress and wall pressure shift spatially from the distal end in models of low inclination (0–45 deg) and circumscribe the aneurysmal wall for an inclination angle of 90 deg. Accordingly, it is concluded that high angles of inclination increase rupture risks while lower inclinations are comparatively safe.

Glenosphere inclination and clinical outcomes after reverse shoulder arthroplasty

BackgroundThe relationship of numerous implant design and positioning-related variables with range of motion and clinical outcomes have been investigated for reverse shoulder arthroplasty (RSA). While glenosphere inclination has been investigated with regards to implant fixation and scapular notching, little research has been done on the association between glenosphere inclination and clinical outcomes. Therefore, the primary objective of this study was to investigate the relationship between preoperative glenoid inclination, postoperative glenosphere inclination and inclination change (∆INC) from pre- to postoperative on clinical outcomes after RSA. MethodsA multicenter retrospective study was conducted of RSAs with minimum 2-year clinical follow-up. All included patients had the same RSA prosthesis. Preoperative, postoperative, and ∆INC from pre-to postoperatively were measured for each patient. The primary study outcome was the minimum 2-year ASES score. Secondary outcomes were active range of motion, Constant-Murley score and Western Ontario Ostearthritis Shoulder (WOOS) score at a minimum of 2 years postoperatively. Receiver-operator characteristic curve analyses were performed to determine if any significant thresholds in inclination existed. Univariate analyses were performed with ANOVA to compare subgroup means. Finally, a multivariate logistic regression was performed to examine each inclination variable as a predictor of clinical outcome while controlling for patient and implant-related variables. ResultsEighty seven patients were included in the study. The mean age was 70 years and 53% of patients were male. The examiners had excellent reliability determined by intraclass correlation coefficients for all 3 measurements. There was no apparent correlation between preoperative inclination, postoperative inclination or ∆INC with minimum 2-year ASES scores. This was confirmed in the receiver-operator characteristic analyses, where no significant thresholds were found for each of the 3 assessed measurements (P> .05 for all analyses). A subgroup analysis comparing patients with low preoperative inclination (<10°) and patients with high preoperative inclination (>10°) stratified by the ∆INC demonstrated no significant association with inclination (P > .05 for all comparisons). In the multivariate regression analysis, inclination had no significant association with the minimum 2-year ASES scores. ConclusionFor the studied implant system, preoperative inclination, postoperative inclination and ∆INC did not have a significant association with postoperative clinical outcomes after RSA. Level of evidenceLevel III; Retrospective Comparison Study