Despite the simple impact of a rigid particle being a centuries-old problem, a conclusive treatment of the general case is still outstanding. The influences of particle shape as well as elastic and plastic deformation of the particle upon contact significantly complicate the problem. Experiments have shown the possibilities of backward movement as well as forward movement with backward rotation after an impact. This paper investigates the planar impact of a disc and square particle under systematic variation of the impact angle and initial particle orientation. We investigate the kinematic variables of the particle, both post-impact as well as their evolution during contact. For impacts with friction we find oscillatory behaviour of the tangential contact force in both discs and squares depending on the impact angle and initial particle orientation. We further demonstrate the possibility of backwards deflection for square particles with backward orientation under steep impact angles, which is not possible for round particles under the same conditions. In contrast, high deflection angles are achieved with a kind of “double-impact” where the centroid of the particle moves away from the plane so that the surface detaches first, but reconnects again due to induced rotation, which also is not possible for round particles. Lastly, we present different coefficients of restitution for the square particle with respect to the combined influence of impact angle and particle orientation upon impact.
This study examines wintertime wind-induced near-inertial internal waves (NIWs) in the Sea of Japan. Energy source of NIWs from the atmosphere is the greatest in winter, but energy propagation into the ocean and contribution to turbulent mixing are unclear. We analyzed horizontal current records from a mooring system covering the top 1200 m at the full depth of 1770 m. During the winter, noticeable NIW events were caused by the cold outbreaks from the Eurasian continent. Although downward-propagating NIWs were dominant, upward-propagating NIW was identified around the main pycnocline in March 2020, when FATO mooring site located the north of an anti-cyclonic eddy (ACE) center. A detailed examination of wave properties near the interface revealed that the intrinsic frequencies of the downward- and upward-propagating waves were nearly coincident with 1.1f. This result implies that upward-propagating NIW is the reflected wave of downward-propagating NIW generated by the same atmospheric disturbances. Turbulent mixing due to Kelvin–Helmholtz instability was implied during the reflection event. The reflection layer was likely the lower pycnocline, splitting the Tsushima Warm Current water from the Japan Sea Proper Water. We discussed the following reflection mechanisms: reflection at the seafloor, partial reflection at the internal boundary, and internal reflection around the edge of ACE. One interpretation would be the internal reflection. The ray-tracing calculations using an idealized ACE structure revealed that the temporal vertical reflection of NIW and kinetic energy amplification around the rim of the ACE.
We performed powder neutron diffraction experiments at T = 2.5 K on partially deuterated L-tartrate copper tetrahydrate, a magnetic material with a chiral crystal structure. Rietveld refinement of the powder neutron diffraction patterns enabled the determination of hydrogen (deuterium) atom positions within the one-dimensional hydrogen-bonding network previously reported in the literature (Rashidipour et al. in Arab J Chem 10:S3167, 2017). Additionally, we measured the temperature dependence of the magnetic susceptibility from 2 to 300 K for both deuterated and non-deuterated L-tartrate copper samples. Analysis using a model with two types of one-dimensional chains showed that the effect of deuteration on magnetic properties is minimal within the measured temperature range.
Bathynomus doederleini is a deep-sea isopod belonging to the subphylum Crustacea that is frequently captured as bycatch. Although B. doederleini has recently attracted interest as a potential novel marine food resource, its allergenic risk has not been evaluated. Because crustacean-allergic individuals may react to conserved allergens present across crustaceans, we investigated the molecular and immunological properties of B. doederleini proteins. Immunoassays using sera from crustacean-allergic patients with no prior exposure to B. doederleini demonstrated significant immunoglobulin E (IgE) reactivity to the heated extract of B. doederleini and revealed a major IgE-reactive band at approximately 37 kDa. Western blotting using an anti-tropomyosin antibody and liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis identified the 37 kDa protein as tropomyosin (TM). The TM cDNA containing the complete open reading frame (ORF) was cloned, revealing a transcript encoding a 284-amino-acid polypeptide sharing 91–98
This study characterizes the microstructure of salmon muscle, in special the quantity and thickness of the myotomes and myosepta tissues, at five locations (belly, loin, second cut, top loin, and tail) using magnetic resonance imaging (MRI) in order to build simulation models that consider the structure of each tissue to investigate their effect on the electrical behavior during ohmic heating (OH). A block from each location was subjected to OH from 5 degrees C to 70 degrees C under an applied voltage of 20 V at 20 kHz in both directions of the electric current (parallel and series) to the muscle arrangement. The OH systems were evaluated experimentally and using three-dimensional computer simulation models. Experimental temperature profiles successfully validated the accuracy of the model results in parallel and series directions at two different locations, showing a low error across all 20 conditions assessed, with 14 conditions exhibiting excellent accuracy (RMSRE <10 %), four conditions showing good accuracy (10 % < RMSRE <20 %), and two conditions presenting fair accuracy (20 % < RMSRE <30 %). Salmon block with thinner tissue (myotomes and myosepta) layers presented a higher heating rate during OH, following the order: tail > top loin > second cut > loin > belly. 3D distributions of current density and temperature during OH were visualized through computer simulations. The results confirmed that the salmon muscle microstructure predominantly influences heat generation distribution according to the current direction. Approaches combining MRI evaluation and mathematical simulation demonstrated their potential to evaluate the OH of food systems of complex microstructures which can be relevant in the design of novel products.
