Hydrogen-to-silicon ratio in meteoroids depends on size, not velocity


  • H-to-Si ratio shows no correlation with meteor velocity, but exhibits a clear positive correlation with photometric mass for cometary meteoroids. The amount of hydrogen detected isn’t mainly determined by atmospheric entry effects. Bigger cometary meteoroids retained more volatiles (hydrogen-bearing compounds).


  • Meteoroids that came from asteroidal sources (rocky parent bodies) showed very low hydrogen signals, even for large masses.


  • The intensity equation of a spectral line tells us how much light is emitted when atoms or ions transition from a higher energy level to a lower level.


  • By comparing the intensity of Hα and Si II lines, the researchers calculated the relative abundance of hydrogen vs silicon (H/Si) in the meteor plasma — once they correct for the temperature and atomic constants.


  • The researchers used the Saha equation which gives the ratio of ionized to neutral atoms at given temperature and electron density​ in the plasma. (Here to find how much of the total silicon is in the Si II state.)



High-inclination Centaurs originate from polar corridor


  • There exist stable regions (reservoirs) of small icy objects beyond Neptune that are in highly tilted (high-inclination) or even retrograde orbits (opposite to planet). The region is called the polar corridor.

  • Centaurs cannot form from the flat, low-inclination regions of the Solar System (like the Kuiper Belt). They come from high-inclination source zones that already existed beyond Neptune.

  • TNO( transneptunian objects) are small icy bodies that orbit the Sun beyond Neptune, mostly in the region known as the Kuiper Belt and beyond from about 30 AU to 1000 AU

  • Centaurs are small icy bodies that orbit between Jupiter and Neptune — that is, inside the region of the giant planets.Distance range: roughly 5 to 30 AU from the Sun. They are thought to be temporary— their orbits are unstable because of strong gravitational interactions with the giant planet.

  • TNOs located in the outer Solar System can be perturbed inward by Neptune’s gravity, the Galactic tide, or passing stars. As their orbits shrink and cross Neptune’s region, they become Centaurs.

  • Tisserand inclination pathway equation:

  • The equation describes the inclination of a small body’s orbit (like a TNO or Centaur) in terms of its orbital parameters relative to a planet (like Neptune). Tisserand parameter with respect to Neptune, TN​, neatly organizes how strongly Neptune interacts with an orbit. If TN is small or negative, it means the orbit strongly interacts with Neptune’s region.

  • TN=0.5 at about 80° inclination, TN=−1.5​ at about 122° inclination. 

  • Source: https://arxiv.org/html/2511.03021v1


Catheter with sensing pressure


  • Researchers developed smart catheter that can sense pressure inside the body in real time


  • When doctors use catheters (thin flexible tubes) inside the body for diagnosis or treatment, it’s hard to know how much pressure the catheter applies to the surrounding tissues. Too much pressure can damage tissues, while too little pressure might make the procedure less effective.


  • They integrated tiny piezoelectric sensors (which generate electric signals when pressure applied) into the catheter surface. This works across a wide pressure range (0–80 kPa).

  • Pressure at multiple directions inside the body (like in blood vessels or airways) can be measured which help doctors during surgeries. 

  • Sensitivity is measured by,

  • Here The custom signal acquisition circuit is designed to: Amplify the weak voltage, Convert it into digital data, and Display the pressure graph on screen instantly

  • They used a thermal drawing process for catheter fabrication. The main sensing material is P(VDF-TrFE)poly vinylidene fluoride-co-trifluoroethylene – a flexible plastic film that reacts to pressure and can bend easily without breaking.

  • Source: https://arxiv.org/abs/2511.00978


Use of Kubelka–Munk model in surgery


  • Researchers used the Kubelka–Munk model and fiber optics for fast, real-time tissue analysis in surgery. Kubelka–Munk model helps us predict how much light is reflected and transmitted and from that, we can estimate how much the material or tissue absorbs and scatters light.

  • Here differential equations are used.

  • K (absorption) and S (scattering) parameters

  • Radiation Transfer Theory (RTT) gives optical coefficients Absorption and scattering coefficients. This method needs detailed input.


  • Kubelka–Munk model needs only basic measurable quantities — diffuse reflectance and transmittance. Light moves in only two opposite directions(upward and downward) are considered. This allows doctors to measure optical properties of tissues during surgery in seconds, measuring how intestinal tissues absorb and scatter light during surgery.


  • The researchers used Monte Carlo modeling, which is a numerical method for solving the Radiation Transfer Theory (RTT) equation, to generate reference data. They then applied the Kubelka–Munk model, based on differential equations, to measure absorption (μₐ) and scattering (μ′ₛ) coefficients of intestinal tissues.

  • Source: https://www.researchgate.net/publication/396682973_Application_of_the_Kubelka-Munk_model_for_fast_intraoperative_analysis_of_intestinal_optical_properties_using_a_fiber_optic_spectrometer


Scaffold with gradually changing porosity


  • Scaffold with gradually changing porosity creates better mechanical conditions for bone healing than with uniform structure.(In a medical context, a scaffold is a 3D porous structure made from biomaterials that acts as a temporary support).


  • The Functionally Graded (FG) scaffold is a scaffold where the porosity, stiffness, or composition varies smoothly across its volume to better match how natural bone behaves.


  • Scaffolds with increasing porosity (more holes) toward the metal plate transferred stress better, The improvements were strongest for titanium Ti-6Al-4V material. The more gradual the porosity change, the better the mechanical distribution inside the scaffold.


  • The authors used Finite Element Analysis (FEA).


  • To control porosity, they create a third order polynomial relation between strut thickness (S) (thickness of the bars of the lattice) and porosity(n).

  • This relationship was used to design scaffolds with precise porosity gradients.


  • They measured octahedral shear strain (ε_oct) : this measure combines tension, compression, and shear effects into one value.

  • Uniform scaffolds with 50% porosity exhibited relatively low octahedral shear strain values, particularly adjacent to the fixation plate, indicating regions of stress shielding while Functionally Graded scaffolds show progressively higher strain levels and more extensive strain distribution within the scaffold.


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