Large Ring Research Articles

Synthesis of HZSM-5@activated carbon for improving aromatic production from catalytic pyrolysis of biomass

HZSM-5 widely used for the catalytic pyrolysis of biomass exhibits the drawbacks of high diffusion resistance and large coke production. To effectively enhance the catalytic efficiency and alleviate the coke deposition, a novel promising catalyst, HZSM-5 coated activated carbon (HZSM-5@AC), was prepared for the first time for in-line upgrading the pyrolysis products of soybean straw. Various catalysts including HZSM-5, activated carbon, and the HZSM-5@AC catalysts with different HZSM-5 to activated carbon mass ratios were characterized. The results showed that the HZSM-5 was successfully coated on the surface of activated carbon and the addition of activated carbon introduced a mesoporous structure and more acidic sites to the catalyst. The catalytic performance on the biomass conversion showed that the catalyst with HZSM-5-to-activated carbon mass ratio of 18:5 (18HZSM-5@5AC) had the highest catalytic efficiency on the conversion of biomass into aromatics with a selectivity of 99.5%, including 75.68% of benzene, toluene, and xylenes (BTX) with a yield of 74.68 mg/g. Moreover, a possible pathway for HZSM-5@AC catalyzed biomass pyrolysis was proposed through analyzing the conversion of model compounds. The catalyst cycling experiments demonstrated the higher stability of HZSM-5@AC than the parent HZSM-5 and activated carbon. TG, FTIR, Raman and SEM showed that the spent HZSM-5@AC was hardly structurally changed with a low coke yield of 0.08%. However, the spent HZSM-5 was partly structurally deactivated by large aromatic ring systems with a coke yield of 3.74%. SEM results also showed that a large amount of polymerized material encapsulated the surface of the spent HZSM-5.

A balanced mitral leaflet and large ring strategy avoids systolic anterior motion in Barlow's disease.

Mitral valve repair for Barlow's disease offers good outcomes but excessive and myxomatous valvular tissue is associated with systolic anterior motion. Although valvular disease might progress after repair and cause long-term systolic anterior motion, few reports focus on this aspect. Herein, we will review our 16-year experience with mitral valve repair for Barlow's disease and systolic anterior motion incidence. We retrospectively reviewed surgical outcomes of 92 cases of mitral valve repair using a balanced leaflet/large ring strategy plus median sternotomy for Barlow's disease (median age 45.1 ± 12.7years old [19-72], 37 females) from 2004 to 2019. Concomitant surgeries, except for tricuspid valve or anti-arrhythmic surgeries, were excluded. The follow-up period was 5.8 ± 4.4years with no deaths. Patients had mitral regurgitation of grade 3/4 (15 cases) or 4/4 (77 cases) due to anterior leaflet (3 cases), posterior leaflet (75 cases), or bileaflet (14 cases) prolapse, with chord elongation (39 cases), chord rupture (22 cases), or a combination of both (14 cases). All cases required ring annuloplasty (median size of 33.0 ± 5.4mm) combined with leaflet resection (91 cases), chord intervention (12 cases), or indentation closure (2 cases). No case had short- or long-term SAM. The freedom-from-mitral-regurgitation (of greater than grade 2/4) rate was 94.1% over 5years and 76.0% over 10years without reoperation. Our two-pronged strategy for mitral valve repair in Barlow's disease avoids systolic anterior motion over the long-term, with good outcomes.

Can Aromaticity be Evaluated Using Atomic Partitions based on the Hilbert-space?

Aromaticity is a fundamental concept in chemistry that explains the stability and reactivity of many compounds by identifying atoms within a molecule that form an aromatic ring. Reliable aromaticity indices focus on electron delocalization and depend on atomic partitions, which give rise to the concept of an atom-in-the-molecule(AIM). Real-space atomic partitions present two important drawbacks: a high computational cost and numerical errors, limiting aromaticity measures to medium-sized molecules with rings up to 12 atoms. This restriction hinders the study of large conjugated systems like porphyrins and nanorings. On the other hand, traditional Hilbert-space schemes are free of the latter limitations but can be unreliable for the large basis sets required in modern computational chemistry. This paper explores AIMs based on three robust Hilbert-space partitions --meta-Löwdin, Natural Atomic Orbitals (NAO), and Intrinsic Atomic Orbitals (IAO)--which combine the advantages of real-space partitions without their disadvantages. These partitions can effectively replace real-space AIMs for evaluating the aromatic character. For the first time, we report multicenter index (MCI) and \iring values for large rings and introduce ESIpy, an open-source Python code for aromaticity analysis in large conjugated rings.

Large Ring Test for Evaluation of Restrained Shrinkage Cracking: Calibration and Experimental Trial

The durability of shotcrete tunnel linings is significantly affected by restrained shrinkage cracking. Given the unique characteristics of shotcrete applied in tunnel linings, especially when dealing with accelerated shotcrete containing reinforcement fibres, it is necessary to upscale the ring test commonly used. This paper presents a comprehensive experiment using large ring tests with cast concrete to investigate the impact of upscaling ring test geometry. The two ring specimens demonstrated comparable cracking age (22 days) and strain measured in the steel ring, suggesting that consistent results can be obtained through the proposed instrumentation, calibration, and correction methods. Moreover, the estimated induced tensile stresses of the concrete rings (2.8 and 2.7 MPa) are slightly lower than the predicted tensile strength (3.3 MPa) at the age of cracking, which indicates that some driving forces contributing to restrained shrinkage cracking were not indicated in the strain gauge readings. Furthermore, the study identified multi-crack formation and additional potential causes for crack initiation, which include self-restraint due to the moisture gradient in the vertical direction, deflection of the concrete ring caused by its self-weight, and friction on the contact surface of the support. Therefore, optimising the geometry of the ring specimens and the apparatus is imperative to minimise additional driving forces and unmeasurable restraints for crack initiation, especially when employing the stress rate method to assess cracking potential.

Hydraulic characterization of Pwales aquifer in Malta Island preparatory for planning managed aquifer recharge (MAR) pilot plant

Whitin the aim to reduce the water demand by increasing water use efficiency and providing alternative water resources, and mainly to meet the demand of good quality irrigation water for agriculture, the Energy and Water Agency of Malta is planning to develop a Managed Aquifer Recharge pilot plant in Pwales Valley to improve the quantitative and qualitative status of the groundwater body. For this reason a detailed hydraulic characterization of the valley was carried out. Specifically, hydraulic properties of the rocks that constitute strata atop of the Pwales aquifer were determined by means of both laboratory measurements on samples and field test carried out in the studied area. The water retention and hydraulic conductivity functions, which relate the matric potential, ψ, and hydraulic conductivity, K, to the water content, θ, respectively, were measured using three experimental methods because each of them allows to obtain data points in a specific wet range. The water retention and hydraulic conductivity functions were measured on samples extracted from blocks of Upper Coralline Limestone formation, that hosts the aquifer, collected in three different quarries: Ghian Tuffieha, Mellieha and San Martin areas. The measured water retention and hydraulic conductivity data were fitted with LABROS SoilView Analysis software that allows to describe the functions and obtain the parameters which are crucial for modelling the water flow and transport processes in the critical zone. In addition, large ring infiltrometer test was carried out to determine the field saturated hydraulic conductivity, Kfs, and the average infiltration rate. Knowledge of the hydraulic characteristics of the Upper Coralline Limestone, completely missing in the scientific literature, allows developing a local groundwater-flow numerical model in order to better describe and understand how the water flows from the soil to the groundwater of the valley and visualize different environmental scenarios such as the potential effects of Managed Aquifer Recharge plant in the Pwales Coastal Groundwater Body.

Ship Global Traveling Path Optimization via a Novel Non-Dominated Sorting Genetic Algorithm

Due to the intensification of economic globalization and the impact of global warming, the development of methods to reduce shipping costs and reduce carbon emissions has become crucial. In this study, a multi-objective optimization algorithm was designed to plan the optimal ship route for safe cross-ocean navigation under complex sea conditions. Based on the traditional non-dominated sorting genetic algorithm, considering ship stability and complex marine environment interference, a non-dominated sorting genetic algorithm model considering energy consumption was designed with the energy consumption and navigation time of the ship as the optimization objectives. The experimental results show that although the proposed method is 101.23 nautical miles more than the large ring route, and the voyage is increased by 10.1 h, the fuel consumption is reduced by 92.24 tons, saving 6.94%. Compared with the traditional genetic algorithm, the voyage distance and time are reduced by 216.93 nautical miles and 7.5 h, and the fuel consumption is reduced by 58.82 tons, which is almost 4.54%. Through experimental verification, the proposed model can obtain punctual routes, avoid areas with bad sea conditions, reduce fuel consumption, and is of great significance for improving the safety and economy of ship routes.

Insights into pyrolysis process of coconut shell waste hydrochar: In-situ structural evolution and reaction kinetics

Coconut shell (CS) can be efficiently utilized by coupling hydrothermal carbonization (HTC) pretreatment with pyrolysis to meet the goal of global green development. In-situ Raman spectroscopy and thermogravimetric analyzer (TGA) were adopted to investigate the structural evolutions and reaction kinetics characteristics of hydrochar during the pyrolysis process. According to the results, the intensity of peak D and peak G in Raman spectrum decreased with increasing hydrothermal degree. Mild HTC treatment (≤200 °C) led to an increase in ID/IG, indicating the formation of large aromatic rings through small ring condensation. In contrast, severe HTC treatment (≥220 °C) reduced the ID/IG ratio, indicating an increased polycondensation of aromatic compounds and a higher degree of aromatization, resulting in larger molecules sizes. The spectral area below 400 °C reduced with increasing pyrolysis temperature due to the reduction of oxygen-containing functional groups and thermal radiation. Above 400 °C, the total area remains stable as the Raman spectrum scattering ability increases due to char formation and aromatization reactions. HTC-200 exhibited an increase in ID/IG from 0.54 to 0.72 and ID/I(Me + Ke + GL) from 0.58 to 0.68 with increasing pyrolysis temperatures. The activation energy during pyrolysis ranged from 194.50 to 238.34 kJ/mol for CS and 217.51–259.51 kJ/mol for HTC-200. Hydrothermal carbonization had a significant effect on pyrolysis behavior of hydrochar, as it was found that the mild HTC hydrochar followed D-type diffusion models when conversion rate was less than 0.65, and transitioned to higher reaction order in the late-stage of pyrolysis.

Effect of Volatile-Char Interaction on Biochar Containing N/O-Functional Group During Reburning Denitrification

ABSTRACT The influence of functional groups such as N/O and microcrystalline structure in biochar on NO reduction is critical. The interaction between volatile and char can significantly alter the activity of char, thereby altering its ability to reduce NO. Unfortunately, the impact of this interaction on NO reduction is still unclear. In this study, the effect of this interaction at 900°C on the physicochemical structure of model biochar containing N/O-functional group during reburning denitrification was investigated. This paper simulates the volatile of reactive species containing H and O through pyrolysis of polyethylene and polyethylene glycol, respectively. The results indicate that the H- and O-containing reactive species play distinct roles during the interaction between volatile and char, but both species consume the amorphous carbon structure. The H-containing actives significantly increased the condensation of the aromatic rings and the O and N contents of the char decreased by 1.36% and 0.43% respectively. There were also significant interconversions between the N functional groups, with the content of N-5 increasing by 12% and that of N-6 by 2%. Consequently, the ability of char to reduce NO decreased by 29%. The O-containing reactive species will react with the char to form C-O composite oxides, thus increasing the O content with 1.88% and preventing the carbon structure from being condensed into a large aromatic ring system. Simultaneously, it was found that after the action of O-containing reactive species, the content of N decreased by 0.9%, and the N functional group tended to convert to N-5 (pyrrole or pyridone), increasing its content by 27%. Furthermore, char activity was significantly increased and NO reduction capacity increased by 19%.

The mean square displacement of a ballistic quantum particle

A commonly used quantum mechanical formulation of the mean square displacement δ x 2 ( t ) is based on the quantum correlation function of the position operator. While this quantity yields the classically expected result δ x 2 ( t ) ∝ t 2 for a ballistic particle in the interval topology, it is found here to diverge at essentially all times, when evaluated on infinitely large rings. A somewhat different formulation of the mean square displacement in quantum mechanics was proposed in a previous work (R. Marquardt, Mol. Phys. 119, e1971315 (2021)) and yielded the result δ x 2 ( t ) ∝ t for the ballistic particle on an infinitely large ring. Here, it is shown analytically that that formulation yields δ x 2 ( t ) ≡ 0 for the ballistic particle on an infinitely long interval. The two formulations define two different, topology dependent quantities that have the dimension of an area and that could in principle be determined from the same experiment, following a measurement idea proposed in the aforementioned work. That idea is critically reviewed here.

Co-pyrolysis of low-rank coal and rice stalk: A comprehensive study on product distributions, product properties, and synergistic effects

Co-pyrolysis of low-rank coal and rice stalk is an important way to achieve hierarchical and efficient utilization of energy. This work explored how blend ratios (0–100 wt%) and temperatures (773–1073 K) affect pyrolysis product distribution and characteristics. The results showed that a higher rice straw ratio (80 wt%) significantly reduced the yield of char (22.38–26.9 wt%) compared with 20 wt% of rice straw at different temperatures. The yield and physicochemical properties of target products were closely related to process parameters, which can provide a promising opportunity to acquire desired products by reaction conditions optimization. Co-pyrolysis was able to inhibit the production of large aromatic ring structures in char. High temperature promoted the generation of cross-linked structures, which was influenced by the blend ratio. The synergistic effects of BET surface area and pore volume were most pronounced when the J content was 40 wt% at 873 K, and their increments were 59.6 m2/g and 0.027 cm3/g, respectively. For the char derived from lower rice straw proportions (0, 20, and 40 wt%), the main combustion range and the maximum combustion rate temperature showed a progressive shift towards higher values with temperature increasing. The research is valuable of guiding high-value utilization of agricultural residues and energy transitions.

Sharp bend and large FSR ring resonator based on the free-form curves on a thin-film lithium niobate platform.

Sharp bends are crucial for large-scale and high-density photonics integration on thin-film lithium niobate platform. In this study, we demonstrate low-loss (<0.05 dB) and sharp bends (Reff = 30 µm) using free-form curves with a 200-nm-thick slab and a rib height of 200 nm on x-cut lithium niobate. Employing the same design method, we successfully realize a compact fully-etched ring resonator with a remarkably large free spectral range of 10.36 nm experimentally. Notably, the equivalent radius of the ring resonator is a mere 15 µm, with a loaded Q factor reaching 2.2 × 104.

High-contrast JWST-MIRI Spectroscopy of Planet-forming Disks for the JDISC Survey

The JWST Disk Infrared Spectral Chemistry Survey (JDISCS) aims to understand the evolution of the chemistry of inner protoplanetary disks using the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST). With a growing sample of >30 disks, the survey implements a custom method to calibrate the MIRI Medium Resolution Spectrometer (MRS) to contrasts of better than 1:300 across its 4.9–28 μm spectral range. This is achieved using observations of Themis family asteroids as precise empirical reference sources. The high spectral contrast enables precise retrievals of physical parameters, searches for rare molecular species and isotopologues, and constraints on the inventories of carbon- and nitrogen-bearing species. JDISCS also offers significant improvements to the MRS wavelength and resolving power calibration. We describe the JDISCS calibrated data and demonstrate their quality using observations of the disk around the solar-mass young star FZ Tau. The FZ Tau MIRI spectrum is dominated by strong emission from warm water vapor. We show that the water and CO line emission originates from the disk surface and traces a range of gas temperatures of ∼500–1500 K. We retrieve parameters for the observed CO and H2O lines and show that they are consistent with a radial distribution represented by two temperature components. A high water abundance of n(H2O) ∼ 10−4 fills the disk surface at least out to the 350 K isotherm at 1.5 au. We search the FZ Tau environs for extended emission, detecting a large (radius of ∼300 au) ring of emission from H2 gas surrounding FZ Tau, and discuss its origin.

Possible Tests of Fundamental Physics with GINGER

The GINGER (gyroscopes in general relativity) project foresees the construction of an array of large frame ring laser gyroscopes, rigidly connected to the Earth. Large frame ring laser gyroscopes are high-sensitivity instruments used to measure angular velocity with respect to the local inertial frame. In particular, they can provide sub-daily variations in the Earth rotation rate, a measurement relevant for geodesy and for fundamental physics at the same time. Sensitivity is the key point in determining the relevance of this instrument for fundamental science. The most recent progress in sensitivity evaluation, obtained on a ring laser prototype, indicates that GINGER should reach the level of 1 part in 1011 of the Earth’s rotation rate. The impact on fundamental physics of this kind of apparatus is reviewed.

Copine C plays a role in adhesion and streaming in Dictyostelium

ABSTRACT Copines are a family of calcium-dependent membrane-binding proteins. To study these proteins, anull mutant for cpnC was created in Dictyostelium, which has six copines genes (cpnA-cpnF). During development, cpnC− cells were able to aggregate, but did not form streams. Once aggregated into mounds, they formed large ring structures. cpnC− cells were less adherent to plastic substrates, but more adherent to other cells. These phenotypes correlated with changes in adhesion protein expression with decreased expression of SibA and increased expression of CsaA in developing cpnC− cells. We also measured the expression of RegA, a cAMP phosphodiesterase, and found that cpnC− cells have reduced RegA expression. The reduced RegA expression in cpnC− cells is most likely responsible for the observed phenotypes.

Enhanced erosion resistance in semiconductor reactive ion etcher focus ring with large grain PVT SiC

SiC focus rings are crucial for ensuring the uniformity of plasma reactive ion etching (RIE) in semiconductor processing. While chemical vapor deposition (CVD) is typically employed to fabricate large scale focus rings, these rings often show multiple pinhole surface defects following RIE processing. Here we introduced an approach to producing focus rings using a physical vapor transportation (PVT), harnessing a modified setup. Specific microscopic analysis demonstrated that SiC focus rings prepared through the PVT method significantly showed millimeter scale grain sizes with fewer grain boundaries, reducing be formation of pinhole defects. In contrast, focus rings produced by the CVD had microscale smaller grain size, resulting in abundant grain boundaries and numerous defects that were observed on these boundaries. This increase in grain size in the focus rings fabricated through the PVT provided three times higher erosion resistance (etch rate of 0.03 μm/min) compared to those prepared by CVD.

Hybrid manipulation of inkjet-printing deposition pattern of high particle concentration droplet by means of thermal and binary solvent effects

Inkjet-printing of functional material is a well-known drop-on-demand technology used in a wide range of modern applications, such as flexible electronics, biomedical testing, etc. It enables to deliver small amount of materials as ink to the specific location on target substrates. However, it is challenging to precisely manipulate the particle deposition characteristics which is crucial to the quality of the fabricated device. Unlike the traditional passive methods by manipulating the nanoparticle, solvent or substrate surface condition, we propose a passive-active hybrid manipulation method by employing a binary mixture solvent and heating substrate. In this paper, the effects of the solvent mixing ratio, the substrate temperature, the substrate thermal properties on the deposition characteristics of high concentration ITO nano-ink were investigated. Interestingly, we have observed a transition of the classic slim coffee-ring to a fat coffee-ring with a large ring width. A dimensionless number was developed to predict the transition boundary from fat-ring pattern to slim-ring pattern. Finally, the phase diagrams of deposition patterns on three substrates were developed, which were convenient for deposition pattern manipulation in real applications.

Hydrogen-bonding interactions in 5-fluorocytosine-urea (2/1), 5-fluorocytosine-5-fluorocytosinium 3,5-dinitrosalicylate-water (2/1/1) and 2-amino-4-chloro-6-methylpyrimidine-6-chloronicotinic acid (1/1).

Three new compounds, namely, 5-fluorocytosine-urea (2/1), 2C4H4FN3O·CH4N2O, (I), 5-fluorocytosine-5-fluorocytosinium 3,5-dinitrosalicylate-water (2/1/1), 2C4H4FN3O·C4H5FN3O+·C7H2N2O7-·H2O, (II), and 2-amino-4-chloro-6-methylpyrimidine-6-chloronicotinic acid (1/1), C6H4ClNO2·C5H6ClN3, (III), have been synthesized and characterized by single-crystal X-ray diffraction. In compound (I), 5-fluorocytosine (5FC) molecules A and B form two different homosynthons [R22(8) ring motif], one formed via N-H...O hydrogen bonds and the second via N-H...N hydrogen bonds. In addition to this interaction, a sequence of fused-ring motifs [R21(6), R33(8), R22(8), R43(10) and R22(8)] are formed, generating a supramolecular ladder-like hydrogen-bonded pattern. In compound (II), 5FC and 5-fluorocytosinium are linked by triple hydrogen bonds, generating two fused-ring motifs [R22(8)]. The neutral 5FC and protonated 5-fluorocytosinum cation form a dimeric synthon [R22(8) ring motif] via N-H...O and N-H...N hydrogen bonds. On either side of the dimeric synthon, the neutral 5FC, 5-fluorocytosinium cation, 3,5-dinitrosalicylate anion and water molecule are hydrogen bonded through N-H...O, N-H...N, N-H...OW and OW-HW...O hydrogen bonds, forming a large ring motif [R1010(56)], leading to a three-dimensional supramolecular network. In compound (III), 2-amino-4-chloro-6-methylpyrimidine (ACP) interacts with the carboxylic acid group of 6-chloronicotinic acid via N-H...O and O-H...O hydrogen bonds, generating an R22(8) primary ring motif. Furthermore, the ACP molecules form a base pair via N-H...N hydrogen bonds. The primary motif and base pair combine to form tetrameric units, which are further connected by Cl...Cl interactions. In addition to this hydrogen-bonding interaction, compounds (I) and (III) are further enriched by π-π stacking interactions.

Ionized gas extends over 40 kpc in an odd radio circle host galaxy.

A new class of extragalactic astronomical sources discovered in 2021, named odd radio circles (ORCs)1, are large rings of faint, diffuse radio continuum emission spanning approximately 1 arcminute on the sky. Galaxies at the centres of several ORCs have photometric redshifts of z ≃ 0.3-0.6, implying physical scales of several 100 kpc in diameter for the radio emission, the origin of which is unknown. Here we report spectroscopic data on an ORC including strong [O II] emission tracing ionized gas in the central galaxy of ORC4 at z = 0.4512. The physical extent of the [O II] emission is approximately 40 kpc in diameter, larger than expected for a typical early-type galaxy2 but an order of magnitude smaller than the large-scale radio continuum emission. We detect an approximately 200 km s-1 velocity gradient across the [O II] nebula, as well as a high velocity dispersion of approximately 180 km s-1. The [O II] equivalent width (approximately 50 Å) is extremely high for a quiescent galaxy. The morphology, kinematics and strength of the [O II] emission are consistent with the infall of shock ionized gas near the galaxy, following a larger, outward-moving shock. Both the extended optical and radio emission, although observed on very different scales, may therefore result from the same dramatic event.

Tunable quintuple plasmon-induced transparency and the effect of symmetry breaking based on monolayer graphene split rings metasurface

A monolayer graphene metasurface composed of two large graphene split rings (TLGSRs) and two small graphene split rings (TSGSRs) is designed and proposed to achieve a tunable quintuple plasmon-induced transparency (QPIT) by coupled mode theory (CMT) and finite-difference time-domain (FDTD) simulations. We successfully realized and designed quintuple-frequency asynchronous, sextuple-frequency asynchronous, and sextuple-frequency synchronous photoelectric switches by dynamically adjusting the Fermi energy levels of graphene. The switches exhibit remarkable performance characteristics, including amplitude modulation degree (AMD) ranging from 71.0 % to 90.0 % and extinction ratio from 5.37 dB to 9.8 dB. The sensitivity of the proposed metasurface was studied and could reach 474 GHz/RIU. The proposed metasurface exhibits polarization-sensitive features due to its non-central symmetry in the metasurface. Finally, the metasurface symmetry-breaking effect on QPIT is further investigated, and results indicate that triple-PIT, quadruple-PIT, quintuple-PIT, and sextuple-PIT can be mutually transformed and regulated through structural symmetry breaking. In summary, the findings provide valuable guidance for the design of optoelectronic switches, sensors, and modulators.

Onset of glassiness in two-dimensional ring polymers: Interplay of stiffness and crowding.

The effect of ring stiffness and pressure on the glassy dynamics of a thermal assembly of two-dimensional ring polymers is investigated using extensive coarse-grained molecular dynamics simulations. In all cases, dynamical slowing down is observed with increasing pressure, and thereby, a phase space for equilibrium dynamics is identified in the plane of the obtained monomer density and ring stiffness. When the rings are highly flexible, i.e., have low ring stiffness, glassiness sets in via the crowding of crumpled polymers, which take on a globular form. In contrast, at large ring stiffness, when the rings tend to have large asphericity under compaction, we observe the emergence of local domains having orientational ordering at high pressures. Therefore, our simulations highlight how varying the deformability of rings leads to contrasting mechanisms in driving the system toward the glassy regime.