Excess Density Research Articles

Effect of Stocking Density on Behavior and Pen Cleanliness of Grouped Growing Pigs

In recent years, animal cleanliness during production has gradually attracted increasing attention. Although pigs by nature tend to excrete in dark and humid corners, in the prevalent highly intensive pig production, excessive stocking density often restricts the ability of pigs to excrete at designated points, thereby leading to pollution of the pens. To study the effect of stocking density on pen cleanliness and the relevant pig behavior, a total of 216 Landrace × Yorkshire × Duroc hybrid pigs were randomly grouped at 0.5, 0.7, or 0.9 m2 per pig at 59 ± 3 days of age. The temporal and spatial distributions of lying and excreting behavior of pigs were monitored on days 1, 7, and 35 after transfer, and the cleanliness of pig pens under three stocking densities was scored. The results showed that there were no significant differences in excreting or lying time rhythms among the three treatments. In the initial and stable periods of group transfer, the excretion rate of pigs on slatted floors was significantly higher than that on solid floors at 0.9 m2/pig (p < 0.01). During the group stabilization stage and at the end of the experiment, the lying rate of pigs on solid floors under 0.9 m2/pig was 10.81%, that is, 7.43% higher than that of 0.7 m2/pig, and the differences were significant. Judging from the pollution score of the solid floors, the three stocking densities all showed more serious pollution at the corners, and the pollution score of the pens with a density of 0.9 m2/pig was lower than that of the pens with a density of 0.5 and 0.7 m2/pig. The analysis of whether pigs had corresponding behaviors in specific functional areas showed that pigs at a density of 0.9 m2/pig had a 10.14% lower lying rate on slatted floors (the expected excretion area) than on solid floors, whereas the densities of 0.5 and 0.7 m2/pig showed the opposite pattern. Pigs at a density of 0.9 m2/pig had lower excretion rates in both corners of the solid floors (the desired lying area) than that of the 0.5 m2/pig group (p < 0.05) and 0.7 m2/pig group (p > 0.05). These results indicate that when the effective occupied space of pigs was larger, specific behaviors were more likely to occur in the set functional areas, and the cleanliness of the pen was higher. Under the conditions of this experiment, the recommended stocking density for growing pigs was 0.9 m2/pig. Of course, a larger space may be more beneficial to animal health and welfare, but the economic costs must also be considered.

Association of androgen excess and bone mineral density in women with classical congenital adrenal hyperplasia with 21-hydroxylase deficiency.

This study aims to assess BMD and its association with androgen excess in women with CAH. We enrolled 92 women with CAH with 21-OH deficiency and retrospectively reviewed their clinical features, hormone concentrations, body composition, glucocorticoid (GC) dose, and BMD. BMD was not different according to the subtypes of CAH. BMD at the lumbar spine was lower in women with CAH with regular menstruation than those with irregular menstruation (1.081 vs. 1.165g/cm2, P < 0.05). BMD was lower in women with CAH with 17-hydroxyprogesterone (17-OHP) < 10ng/mL than in those with ≥ 10ng/mL (lumbar spine, 1.019 vs. 1.150g/cm2; femur neck, 0.806 vs. 0.899g/cm2; total hip, 0.795 vs. 0.943g/cm2; all P < 0.05). After adjusting for age and BMI in correlation analyses, testosterone concentrations were positively correlated with lumbar spine, femur neck, and total hip BMD (r = 0.46, r = 0.38, and r = 0.35, respectively; all P < 0.05), while 17-OHP was positively correlated with lumbar spine BMD (r = 0.38, P < 0.01). In subgroup analysis, 17-OHP was positively correlated with BMD (lumbar spine, r = 0.22; femur neck, r = 0.22; total hip, r = 0.24; all P < 0.05) only in the group with a total cumulative dose of GC ≥ 156.0g/m2. Androgen excess may have a protective effect on BMD in women with classic CAH and high cumulative doses of GC.

Improved Thermal Modeling and Experimental Validation of Oil-Flooded High-Performance Machines With Slot-Channel Cooling

Thermal management is often considered a bottleneck in the pursuit of the next-generation electrical machines for electrified transportation with a step change in power density. Slot-channel cooling is considered to be an effective cooling technique, either as an independent method or as a secondary heat transfer path, which compliments traditional cooling systems. The slot-channel specific geometry and position effects on the thermal benefits are not thoroughly investigated in the literature, while previous work focuses on passing fluid through the unused space left in between coils forming concentrated windings. In this article, slot-channel cooling is implemented within an oil-flooded cooling system for a high power density motor that is used as a pump. A flexible and detailed lumped parameter thermal network (LPTN) is proposed for the cooling system, with the LPTN used to optimize the slot-channel dimensions and location for obtaining maximum thermal benefits. Finally, a surface-mount permanent magnet (SPM) machine with the optimized slot channel geometry is built and tested to validate the thermal model, experimentally achieving an armature continuous current density in excess of 30 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

LaSiO x - and Al2O3-Inserted Low-Temperature Gate-Stacks for Improved BTI Reliability in 3-D Sequential Integration

Sequential 3-D stacking of multiple CMOS device tiers in a single fabrication flow requires the development of reliable high-<inline-formula> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula>/metal gate (HKMG) stacks at a reduced thermal budget (&#x003C;525 &#x00B0;C). The omission of the customary high-temperature gate-stack annealing results in excessive dielectric defect densities. We have recently demonstrated on MOS capacitors the insertion of &#x201C;defect decoupling&#x201D; layers&#x2013;LaSiO_<i>x</i> for nMOS and Al₂O₃ for pMOS&#x2013;at the interface between SiO₂ and HfO₂ as a promising approach to engineer the high-<inline-formula> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> band lineup and minimize charge trapping for improved bias-temperature-instability (BTI) reliability. In this article, we demonstrate this approach in planar transistors, which allows assessing the impact of defect decoupling on carrier mobility. First, a comparative study on the impact of LaSiO_<i>x</i> and Al₂O₃ insertion is performed, highlighting the different strategies for improving positive BTI (PBTI) and negative BTI (NBTI) reliability. Second, a comprehensive investigation on the effects of LaSiO_<i>x</i> and Al₂O₃ insertion is conducted with a focus on BTI reliability and channel carrier mobility: a lack of penalty (Al₂O₃) or even improved carrier mobility (LaSiO_<i>x</i>) is reported for the dipole-inserted gate stacks. Furthermore, we explore the simplified dual gate-stack integration for CMOS flow. A severe PBTI reliability penalty is observed if an Al₂O₃ layer (for hole trap decoupling) is deposited in the nMOS gate-stack, even if on top of the beneficial LaSiO_<i>x</i> (for electron trap decoupling). In contrast, the pMOS gate-stack is found to be more tolerant to the presence of a residual LaSiO_<i>x</i> layer on top of the beneficial Al₂O₃ layer, suggesting a viable strategy for the simplified dual gate-stack integration. Finally, the reliability improvement is validated also on a FinFET test vehicle.

A Fractal Model for Effective Excess Charge Density in Variably Saturated Fractured Rocks

AbstractEstimating hydraulic properties and monitoring water flow in fractured rocks using self‐potential observations essentially relies on our ability to model streaming potential. One of the most promising approaches for modeling electrokinetic couplings is based on the macroscopic quantification of the excess charge which is effectively transported by pore water flow. In this study, we derive a fractal model to predict the effective excess charge density for fully and partially water saturated fractured media. Fractures are conceptualized as parallel plates with a fractal pattern described by the Sierpinski carpet. From the calculation of the excess charge in a single fracture and a flux averaging upscaling procedure, we obtain closed‐form expressions for the effective excess charge density. This new analytical model explicitly depends on the fracture water ionic concentration, interface properties, water saturation, porosity and permeability. Model predictions under saturated conditions are compared to published data measured in laboratory during hydraulic fracturing. The model development also shows the independence of the excess charge from the pore shapes: when expressed in terms of hydrological parameters, one can find an expression identical to recently published models for sedimentary porous media using capillary tubes. These results extend the validity of the existing models to fractured rocks and highlight the importance of hydraulic parameters for an accurate modeling of electrokinetic couplings.

Flow field characterization between vertical plate electrodes in a bench-scale cell of electrochemical water softening

Abstract To analyze the effect of flow characteristics on electrochemical water softening, characteristics of flow fields in the vicinity of vertical plate electrodes in a bench-scale electrolysis cell for electrochemical water softening were visualized using particle image velocimetry technology, and the hardness drop values under different process conditions were measured. Properly increasing the current density or reducing the electrode spacing can increase the average flow velocity in the electrode gap. Excessive current density will cause bubble accumulation, form a bubble vortex, interfere with the orderly flow of surrounding liquid and reduce mass transfer efficiency. When the electrode spacing is 120 mm, the highest water softening efficiency measured at the current density of 60 A/m2 is 16.56%. When the current density is 50 A/m2, the highest average speed measured at the electrode spacing of 60 mm is 0.00169 m/s, but the highest water softening efficiency measured at the electrode spacing of 90 mm is 23.3%.The circulation efficiency in the electrode gap of a semi-closed structure is lower than that of a free convection structure. The behavior of bubbles is the key to flow and mass transfer. It is important to consider its influence on bubble behavior when optimizing electrochemical parameters.

Hydrostatic vs. non-hydrostatic modelling of density currents developing two dimensionally on steep and mild slopes

Salinity and turbidity currents developing two dimensionally on steep and mild slopes are simulated numerically. An application of the process-based model Delft3D-Flow is presented that is able to capture the dynamics of subaqueous dense underflows by solving the two dimensional over the vertical (2DV) Reynolds-averaged Navier–Stokes equations under hydrostatic (H) and non-hydrostatic (NH) pressure assumptions. The development of conservative density currents that plunge in fresh water as a result of an upstream input of denser salty water and turbidity currents flowing down a fixed sandy bed with uniform slope are thoroughly investigated. Down-slope evolution of the modelled density currents is characterised by water entrainment coefficients that fall within the range of laboratory data. Vertical profiles of both velocity and excess density conform with previous experimental measurements. NH solutions, differently from their H counterparts, are shown to capture in detail time-dependent stages of dense undercurrents, such as the dynamics of their fronts, the passage of their heads as well as the development of Kelvin–Helmholtz (KH) instabilities at their interfaces with the ambient fluid resulting in the velocity pulsing of their bodies. Nonetheless, the H application of Delft3D-Flow predicts fairly well the steady state of salty and turbid undercurrents, thus representing a computationally cost-effective alternative for the modelling of field-scale density currents.

An additively-manufactured molten salt-to-supercritical carbon di-oxide primary heat exchanger for solar thermal power generation – Design and techno-economic performance

The design and techno-economic performance of a compact additively manufactured (AM) molten salt (MS)-to-supercritical carbon di-oxide (sCO2) primary heat exchanger (PHE) for solar thermal application is described. The PHE design consists of sCO2 flow through an array of microscale pin fins while the MS flows through mm-scale rectangular channels. Constraints imposed by AM using laser powder bed fusion method are considered in the design. Structural and fluid flow simulations are performed to arrive at a viable design of the core and headers. A simplified one-dimensional steady state model for the PHE is developed including the impact of surface roughness from the AM process. A process-based cost model is used to determine the tradeoff between thermofluidic design and manufacturing cost.A parametric study is performed using the thermo-fluidic and cost models to determine the set of geometrical and flow variables that result in high power density and low cost, while restricting the pressure drop on the sCO2 side to less than 2% of line pressure. Flow rates of MS and sCO2 were varied over heat capacity rate ratios ranging from 0.2 to 1. Results indicate that it is possible to design a low-pressure drop AM PHE with an effectiveness of 90% and a power density in excess of 10 MW/m3 (including headers). Fabrication of representative nickel superalloy specimens are shown to demonstrate that low-porosity parts with the requisite dimensional tolerance of PHE core can be generated.

NMR spectral parameters of open- and closed-shell graphene nanoflakes: Orbital and hyperfine contributions

Graphene nanoflakes have attracted a growing interest owing to their tunable and unique electronic, optical, and magnetic properties. In particular, recent breakthroughs in the on-surface synthesis and characterization of graphene nanoflakes exhibiting π-magnetism have shown their promising great potential for spintronic applications. In this context, a theoretical investigation on the relative energetic stability, 13C nuclear magnetic resonance (NMR) chemical shifts, magnetically induced currents, hyperfine shifts, and hyperfine coupling constants of graphene nanoflakes of hexagonal and triangular shape has been performed using the density functional theory (DFT). The role played by the size, shape, and atomic site position in the flake on the 13C isotropic chemical shift is thoroughly examined. As a general trend, considering only the orbital contribution, sites from the innermost region of the flake present lower chemical shifts than the ones close to the border and, for large enough systems, such values tend to converge to roughly the graphene one. For the open-shell flakes, the hyperfine shifts and coupling constants exhibit oscillatory behavior, with opposite signs for adjacent sites. The magnitude of these parameters is progressively reduced with the increase in the distance from the edge, where the largest values of excess spin density are concentrated.

Photometric Objects Around Cosmic Webs (PAC) Delineated in a Spectroscopic Survey. II. Morphology, Color, and Size Dependences of the Stellar–Halo Mass Relation for Massive Galaxies

Abstract In this paper, we report a robust measurement of the morphology, color, and galaxy size dependences of the stellar–halo mass relation (SHMR) at the high-mass end (1011.3 M ⊙ &lt; M ⋆ &lt; 1011.7 M ⊙) at redshift z s ∼ 0.6. 3 3 Throughout the paper, we use z s for redshift and z for the z-band magnitude. Applying our method, Photometric objects Around Cosmic webs (PAC), developed in a previous work to Baryon Oscillation Spectroscopic Survey and Hyper Suprime-cam Subaru Strategic Program observations, we measure the excess surface density ( n ¯ 2 w p ( r p ) ) of satellites around massive central galaxies with different morphologies indicated by the Sérsic index n. We find that more compact (larger n) central galaxies are surrounded by more satellites. With the abundance matching method, we estimate the halo mass for the central galaxies and find that it increases monotonically with n, solid evidence for a morphology dependence of the SHMR. Specifically, our results show that most compact galaxies (n &gt; 6) have a halo mass around 5.5 times larger than disk galaxies (n &lt; 2). Similarly, using the effective radius R e and the rest-frame u − r color, we find that red (large) galaxies reside in halos that are in average 2.6 (2.3) times more massive than those hosting blue (small) galaxies.

Consistent explanation for the cosmic-ray positron excess in p-wave Breit\u2013Wigner enhanced dark matter annihilation

Dark matter (DM) annihilation in the galactic halo can be enhanced relative to that in the early Universe due to the Breit–Wigner enhancement, if the DM particles annihilate through a narrow resonance. Although the s-wave Breit–Wigner enhancement can provide a consistent explanation for both the observed cosmic-ray (CR) positron excess and the DM thermal relic density, it is severely constrained by the observations of gamma rays from dwarf spheroidal satellite galaxies (dSphs) and the cosmic microwave background (CMB), which have relatively lower allowed DM annihilation cross section and typical DM velocities than that in the galactic halo. Furthermore, in the s-wave Breit–Wigner enhancement, the case where the resonance mass is below a threshold (twice the DM mass) is ruled out due to the monotonically increasing annihilation cross section with decreasing DM velocity. In this work, we consider Breit–Wigner enhanced p-wave DM annihilation. We explore the parameter regions which can simultaneously account for the CR positron excess and DM thermal relic density without violating the constraints from dSphs gamma rays and CMB. We show that the velocity-dependent cross section in this scenario can peak around the typical DM velocity in the galactic halo for the resonance mass both above and below the threshold. Moreover, the highly suppressed annihilation cross section at extremely low DM velocity can evade the constraints from dSphs gamma rays and CMB easily, which results in larger allowed parameter regions than that in the s-wave case.

Effect of heat treatment on the mechanical and biocorrosion behaviour of two Mg-Zn-Ca alloys

The effect of heat treatment on the mechanical and biocorrosion behaviour of the Mg-1 wt.% Zn-1 wt.% Ca (ZX11) and Mg-3 wt.% Zn-0.4 wt.% Ca (ZX30) alloys was evaluated. For this purpose, three-point bending tests as well as electrochemical and immersion tests in Hank's solution were performed on both alloys in four different thermal conditions: as-cast, solution-treated, peak-aged and over-aged. Microstructural examinations revealed that the as-cast ZX11 and ZX30 alloys exhibit a microstructure composed of α-Mg grains separated by large Mg2Ca and Ca2Mg6Zn3 particles and by large Ca2Mg6Zn3 particles, respectively. During solution treatment, the Ca2Mg6Zn3 precipitates at the grain boundaries (GBs) are fully dissolved in the ZX11 alloy, but mainly redistributed to form a more connected configuration in the ZX30 alloy, showing a poor age-hardening response. Consequently, after solution-treatment, galvanic corrosion and corrosion rate decreases in the former, but increases in the latter. The peak-aged condition displays the highest corrosion rate for both alloys, maybe due to an excessive number density of fine Ca2Mg6Zn3 particles acting as cathodic sites. However, the over-aged condition shows the lowest corrosion rate for the ZX11 alloy and a very similar one to that of the as-cast sample for the ZX30 alloy. The ZX11 alloy shows generally better biocorrosion behaviour than the ZX30 alloy to its lower content in the Ca2Mg6Zn3 phase and thus reduced galvanic corrosion. The Mg2Ca phase present in the studied ZX11 alloy has been proved to exhibit an increased corrosion potential, which has been related to an observed enrichment with Zn.

Structural-phase state and defective sub-structure of low-carbon steel welds

The structural-phase state, defective substructure and fracture surface of welds made of low-carbon alloy steel obtained with and without a carbon-containing additive have been investigated by scanning and transmission electron microscopy. A quantitative analysis of the parameters of the structure and dislocation substructure of the weld metal is carried out, and the contributions of the scalar and excess dislocation density to the strength of welds are estimated. It is shown that high values of scalar and excess dislocation density in a weld formed without a carbon-containing additive in the flux can lead to material embrittlement.

Trions in MoS2 are quantum superpositions of intra- and intervalley spin states

We report magneto-photoluminescence spectroscopy of gated MoS$_2$ monolayers in high magnetic fields to 28 T. At B = 0T and electron density $n_s\sim 10^{12}cm^-2$, we observe three trion resonances that cannot be explained within a single-particle picture. Employing ab initio calculations that take into account three-particle correlation effects as well as local and non-local electron-hole exchange interaction, we identify those features as quantum superpositions of inter- and intravalley spin states. We experimentally investigate the mixed character of the trion wave function via the filling factor dependent valley Zeeman shift in positive and negative magnetic fields. Our results highlight the importance of exchange interactions for exciton physics in monolayer MoS$_2$ and provide new insights into the microscopic understanding of trion physics in 2D multi-valley semiconductors for low excess carrier densities.

Study on releasing properties and surface group migration of UV-curable silicone modified polyurethane releasing agent

UV-cured releasing agent is a new type of anti-fouling coatings, which must meet needs of the development in the pressure-sensitive adhesive industry, but also in line with modern environmentally friendly demands. With a step-by-step method, a multi-functional photosensitive silicone modified polyurethane releasing agent was synthesized using a hydroxyalkylsiloxane, toluene diisocyanate, and pentaerythritol triacrylate, carrying out by UV initiating technique to prepare the releasing films. The infrared spectrum and the nuclear magnetic resonance spectrum were used to analyze a molecular structure of the releasing agent. Peel strength tests and morphological tests were used to characterize the application capabilities of the releasing films. X-ray photoelectron spectroscopy and other techniques were simulated the migration of the surface group of the releasing films during the pressure sensitive adhesive adherence. The results showed that the excessive soft segment silicone chain reduced crosslink density, thereby reducing the residual performance, while the excessive polar group density would simultaneously reduce the releasing performance and residual performance. This conclusion reveals the releasing mechanism of the UV-cured releasing agent, and provides an important guiding significance for the molecular design and product development of the new type of releasing agent.

Ethephon Reduces Maize Nitrogen Uptake but Improves Nitrogen Utilization in Zea mays L.

Increasing use of plant density or/and nitrogen (N) application has been introduced to maize production in the past few decades. However, excessive planting density or/and use of fertilizer may cause reduced N use efficiency (NUE) and increased lodging risks. Ethephon application improves maize lodging resistance and has been an essential measure in maize intensive production systems associated with high plant density and N input in China. Limited information is available about the effect of ethephon on maize N use and the response to plant density under different N rates in the field. A three-year field study was conducted with two ethephon applications (0 and 90 g ha−1), four N application rates (0, 75, 150, and 225 kg N ha−1), and two plant densities (6.75 plants m−2 and 7.5 plants m−2) to evaluate the effects of ethephon on maize NUE indices (N agronomic efficiency, NAE; N recovery efficiency, NRE; N uptake efficiency, NUpE; N utilization efficiency, NUtE; partial factor productivity of N, PFPN), biomass, N concentration, grain yield and N uptake, and translocation properties. The results suggest that the application of ethephon decreased the grain yield by 1.83–5.74% due to the decrease of grain numbers and grain weight during the three experimental seasons. Meanwhile, lower biomass, and fluxes in xylem bleeding sap, and total N uptake were observed under ethephon treatments. These resulted in lower NAE and NUpE under the ethephon treatment at a corresponding N application rate and plant density. The ethephon treatment had no significant effects on the N concentration in grains, and it decreased the N concentration in stover at the harvesting stage, while increasing the plant N concentration at the silking stage. Consequently, post-silking N remobilization was significantly increased by 14.10–32.64% under the ethephon treatment during the experimental periods. Meanwhile, NUtE significantly increased by ethephon.

Структура рельсов после экстремально длительной эксплуатации

Using the methods of transmission electron diffraction microscopy the structure phase state and defect substructure in head of differentially quenched 100-meter rails at different depth after ultra long-term operation (passed gross tonnage 1770 mln. tons) are studied. The investigations are carried out along the rail head central axis of symmetry and working fillet rounding radius at the distances 0, 2, 10 mm from the tread surface. Dislocation ferrite substructure is presented by chaotically distributed dislocations and nets. The scalar and excess dislocation density increase as they approach the head rail surface. The values of these parameters on the surface are more than twice the corresponding value at a depth of 10 mm. The value of excess dislocation density is lower than scalar dislocation density which indicates elastic character of crystal lattice curvature-torsion. The quantitative evaluation of mechanisms dislocation strengthening is carried out.

Energy considerations for nonlinear equatorial water waves

&lt;p style='text-indent:20px;'&gt;In this article we consider the excess kinetic and potential energies for exact nonlinear equatorial water waves. An investigation of linear waves establishes that the excess kinetic energy density is always negative, whereas the excess potential energy density is always positive, for periodic travelling irrotational water waves in the steady reference frame. For negative wavespeeds, we prove that similar inequalities must also hold for nonlinear wave solutions. Characterisations of the various excess energy densities as integrals along the wave surface profile are also derived.&lt;/p&gt;

795-nm high-temperature and high-power operating vertical-cavity surface-emitting laser and application in atomic gyroscope

Single-transverse mode vertical-cavity surface-emitting lasers (VCSELs) are preferable optical sources for small low-power atomic sensors, including chip-scale atomic clocks, magnetometers, and gyroscopes.When VCSEL is used as the pump source of nuclear magnetic resonance gyroscope, it is required to have high single-mode output power. Oxide aperture diameter must be sufficiently small (&lt; 4 µm) in a conventional oxide-confined VCSEL to support the fundamental mode alone. However, high series resistance (typically &gt; 200 Ω for GaAs-based VCSEL) from the small aperture limits its output power and reliability due to excessive current-induced self-heating and high current density. It is a very attractive idea to achieve high power operation of an intrinsic single mode VCSEL based on a large oxide aperture by means of epitaxial structure design without introducing additional process steps. Transverse optical confinement in oxide-confined VCSELs crucially depends on the thickness of oxide layer and its position relative to standing wave. Modifying the structure reduces the overlap between the oxide layer and the standing wave as well as the difference in effective refractive index between core and cladding of the VCSEL, thereby reducing the number of transverse modes andincreasing the mode extension beyond oxide aperture. A 795-nm VCSEL is designed and fabricated based on this concept. A cavity structure of VCSEL with gain-cavity detuning of ~10.8 nm at room temperature is adopted in this paper. The effective refractive index and the standing wave distribution of the VCSEL are calculated, and the position of the oxide layer in the epitaxial structure of the VCSEL is optimized according to the standing wave distribution. Finally, the structure with low effective refractive index difference is obtained. The proposed device achieves high single-mode operation of 4.1 mW at 80 ℃, SMSR of 41.68 dB, and OPSR of 27.4 dB. The VCSEL is applied to a nuclear magnetic resonance gyroscope (NMRG) system as pump source due to its excellent device performance, and satisfactory test results are obtained. This paper presents a new method of designing single-mode high power VCSEL and its feasibility is also demonstrated through experimental results.

The First Atmospheric Radio Occultation Profiles From a GPS Receiver in Geostationary Orbit

This paper will present the first radio occultation (RO) electron density profiles of Earth&#x2019;s atmosphere generated from a Global Positioning System (GPS) receiver in Geostationary orbit. The GPS receivers on the GOES-16 (R) and GOES-17 (S) satellites track GPS signals propagated through the Earth&#x2019;s atmosphere and can be used to estimate electron density profiles. Radio occultation profiles from geosynchronous orbit holds the potential to generate unique temporal and spatial atmospheric measurements complementary to those from ground and low Earth orbit space based receivers, including limb observations of the upper atmosphere at altitudes above traditional low Earth orbiting RO satellites. This paper will present details of the GOES satellite GPS receivers and the limitations and challenges in generating RO profiles with its current hardware and software configuration. Following, the temporal and geo-spatial coverage for each of the GOES satellites will be presented, quantifying the frequency and number of GPS signals tracked down to sufficiently low enough altitudes to provide useful atmospheric information. Next, the data processing required to generate excess phase and electron density profiles will be described and demonstrated using two examples of GOES profiles. Subsequently, these two example GOES RO profiles will be compared to and calibrated with an ionospheric model, compared with co-located profiles from the low Earth orbit COSMIC-2 constellation and a ground based ionosonde.