Regular Packing Research Articles

Temporal variability and cell mechanics control robustness in mammalian embryogenesis.

How living systems achieve precision in form and function despite their intrinsic stochasticity is a fundamental yet ongoing question in biology. We generated morphomaps of preimplantation embryogenesis in mouse, rabbit, and monkey embryos, and these morphomaps revealed that although blastomere divisions desynchronized passively, 8-cell embryos converged toward robust three-dimensional shapes. Using topological analysis and genetic perturbations, we found that embryos progressively changed their cellular connectivity to a preferred topology, which could be predicted by a physical model in which actomyosin contractility and noise facilitate topological transitions, lowering surface energy. This mechanism favored regular embryo packing and promoted a higher number of inner cells in the 16-cell embryo. Synchronized division reduced embryo packing and generated substantially more misallocated cells and fewer inner-cell-mass cells. These findings suggest that stochasticity in division timing contributes to robust patterning.

Regular polytopes, sphere packings and Apollonian sections

Regular polytopes, sphere packings and Apollonian sections

Links in orthoplicial Apollonian packings

In this paper, we establish a connection between Apollonian packings and knot theory. We introduce new representations of links realized in the tangency graph of the regular crystallographic sphere packings. Particularly, we prove that any algebraic link can be realized in the cubic section of the orthoplicial Apollonian packing. We use these representations to improve the upper bound on the ball number of an infinite family of alternating algebraic links. Furthermore, the later allow us to reinterpret the correspondence of rational tangles and rational numbers and to reveal geometrically primitive solutions for the Diophantine equation x4+y4+z4=2t2.

Development and analysis of diethylaminoethyl silica-based adsorption column for removing antibiotic resistance genes from wastewater

The current study investigates the efficiency of diethyl aminoethyl silica gel (DEAE-Si) based adsorption column for removing antibiotic resistance genes from secondary treated wastewater. Various column parameters like packing shape, packing size, bed height, and flowrate were analyzed to study their effect and optimize the column performance. The adsorption capacity of the column varied in range of ∼4.5 to 7.8 μg/g of DNA adsorbed. For regular packing of spherical shape, 3 mm–5 mm beads size, 8 cm column height, and flow rate of 0.5 mL/min. Adsorption capacity of 6.23 μg/g with 20 h of break through time and 36 h of saturation time was attained. The column regeneration was performed using NaCl solution at pH 8.5 ± 0.5. High removal efficiency of around 90 % up to 3 regeneration cycles, 75 % for 4th regeneration cycle, and >50 % for 5th regeneration cycle was attained. For practical understanding and to check how the column would perform for increased volumes of wastewater 10 times larger sized column was analyzed in simulated and real secondary treated wastewater matrix. The adsorption capacity attained using large column was around 4.65 μg/g at higher flowrate of 5 mL/min. and constant empty bed contact time resulting in treating up to 17.1 L of wastewater. The overall performance of large column was satisfactory and comparable with the test column in simulated wastewater matrix. >80 % removal efficiency of ARGs of different size in real secondary treated wastewater matrix was achieved on maintaining low flowrate.

Study on hydrodynamic properties and physicochemical stability of regular packing coatings for water isotope separation

Water distillation as a mainstream separation process for water isotopes is widely applied in industrial and basic research. Regular packing, a key component of water distillation, has attracted intense research, and its excellent hydrodynamic properties and physicochemical stability can ensure long-lasting separation performance. Frictional and wear tests, ultrasonic vibration tests and hydraulic erosion tests have been proposed to determine the hydrodynamic properties and physicochemical stability of regular packing with different surface coatings. The results of all tests show that there is no significant change in the shedding, hydrophilicity and separation properties of both samples, indicating the excellent hydrodynamic properties and physicochemical stability of the stamped surface coatings. Meanwhile, an effective way is also provided to verify the performance of the regular packing for use in bulk by the mentioned tests.

On the Microstructure and Dynamics of Membranes Formed by Lipid as From Stenotrophomonas maltophilia, a Member of Gut Microbiome: An EPR Study

AbstractLipid As are the main components of the external leaflet of the outer membrane of Gram-negative bacteria. Their molecular structure has evolved to allow the bacteria survival in specific environments. In the present work, we investigate how and to what extent lipid membranes that include in their composition lipid A molecules of a bacterium of the gut microbiota, Stenotrophomonas maltophilia, differ from those formed by the lipid A of the common Gram-negative bacterium Salmonella enterica, which is not specific to the gut and is here used as a reference. Electron Paramagnetic Resonance (EPR) spectroscopy, using spin-labelled lipids as molecular probes, allows the segmental order of the acyl chain and the polarity across the bilayer to be analyzed in detail. Both considered lipid As cause a stiffening of the outermost segments of the acyl chains. This effect increases with increasing the lipid A content and is stronger for the lipid A extracted from Stenotrophomonas maltophilia than for that extracted from Salmonella enterica. At the same time, the local polarity of the bilayer region just below the interface increases. As the inner core of the bilayer is considered, it is found that the lipid A from Salmonella enterica causes a local disorder and a significant reduction of the local polarity, an effect not found for the lipid A from Stenotrophomonas maltophilia. These results are interpreted in terms of the different lengths and distributions of the acyl tails in the two lipid As. It can be concluded that the symmetrically distributed short tails of the lipid A from Stenotrophomonas maltophilia favors a regular packing within the bilayer.

Intramolecular Hydrogen Bonds Assisted Construction of Planar Tricyclic Structures for Insensitive and Highly Thermostable Energetic Materials.

Safety is fundamental for the practical development and application of energetic materials. Three tricyclic energetic compounds, namely, 1,3-di(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine (ATDT), 5'-nitro-3-(1H-tetrazol-5-yl)-2'H-[1,3'-bi(1,2,4-triazol)]-5-amine (ATNT), and 1-(3,4-dinitro-1H-pyrazol-5-yl)-3-(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine (ATDNP), were effectively synthesized through a simple two-step synthetic route. The introduction of intramolecular hydrogen bonds resulted in excellent molecular planarity for the three new compounds. Additionally, they exhibit regular crystal packing, leading to numerous intermolecular hydrogen bonds and π-π interactions. Benefiting from planar tricyclic structural features, ATDT, ATNT, and ATDNP are insensitive (IS > 60 J, FS = 360 N) when exposed to external stimuli. Furthermore, ATNT (Td = 361.1 °C) and ATDNP (Td = 317.0 °C) exhibit high decomposition temperatures and satisfying detonation performance. The intermolecular hydrogen bonding that produced this planar tricyclic molecular structure serves as a model for the creation of innovative multiple heterocycle energetic materials with excellent stability.

Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation

In a tritium-breeding blanket of a fusion reaction, helium, used as a tritium-purging gas, will purge the tritium breeder pebble beds to extract the tritium in blanket. The purge gas flow characteristics will affect the tritium extraction efficiency. The effect of the fixed wall on the pebble packing structures and purge gas flow characteristics was investigated by combining the discrete element method (DEM) and computational fluid dynamics (CFD) method. The results indicate that the fixed wall leads to a regular packing of the pebbles adjacent to the fixed wall in association with drastic fluctuations in the porosity of the pebble bed, which can affect the purge gas flow behaviors. Further analyses of helium flow behaviors show that the helium pressure in the pebble bed decreases in a linear manner along the flow direction, whereas the pressure drop gradient of helium increases gradually with an increase in the packing factor. The reduction in porosity in the pebble bed leads to a notable escalation in helium flow velocity. Concerning the direction perpendicular to the helium gas flow, the evolution of the cut-plane averaged velocity of helium is similar to that of the porosity, except in the region immediately adjacent to the wall. The pressure drop and flow characteristics obtained in this study can serve as input for the thermohydraulic analysis of the tritium blowing systems in the tritium-breeding blanket of a fusion reactor.

DUST COLLECTION EFFICIENCY UNDER IN-PHASE TURBULENCE CONDITIONS IN THE PRESENCE OF PHASE TRANSITIONS

The article presents the results of a study of the dust collection efficiency in a regular packing layer of a rotoclone-type hybrid apparatus on the particle inertia index in the presence of phase transition processes. The effect of phase transitions on the efficiency of gas purification processes under inphase turbulence conditions is considered. Based on the conditions of stability of the in-phase vortex formation regime of the gas phase in a regular packing layer, the dominant influence of turbulent diffusion mechanisms on the intensity of phase transition processes and, as a consequence, on the dust collection efficiency has been established. In this case, the predominant influence is in the area of highly dispersed and finely dispersed dust fractions. The results of the experimental studying the patterns of dust collection efficiency depending on the particle inertia index in the presence of phase transition processes are presented. The studies were carried out for three phase transition modes: condensation of vaporsfrom a vapour-gas mixture, evaporation of a spraying liquid as well as a neutral mode. Using A.N. Kolmogorov’s hypothesis,the basic equations and results of calculating the numerical values of local characteristics of a turbulent gas flow in a regular packing layer are presented under the assumption of isotropic turbulence realized in a layer of a regular packing, whose local characteristics do not depend on coordinates and direction.

Management of <i>Kotha Roga</i> (Necrotizing Fasciitis) by Modified <i>Ksharapichu</i> (Wound Packing): A Case Report

The present case report was a 25-year-old male patient with severe pain at the right index finger, fever, oedema, and discharge, not having any history of surgery, hypertension, diabetes, or any systemic disorder was diagnosed with kotha roga (necrotizing fasciitis). Presently available treatment for this is broad-spectrum intravenous antibiotics, appropriate hydration support, and meticulous surgical debridement with regular wound packing. But because of contaminated wounds and poor prognosis, herbal therapies have a possibility to cure kotha as they are readily available, and inexpensive. In this case, a kshara formulation i.e., modified ksharpichu was chosen as an atrial medication to be applied locally after everyday cleaning and dressing. It was observed that ksharpichu acted as a debriding agent and healing as well. The case was followed up for 30 days. This study employed pretty simple criteria to gain preliminary observations on the effectiveness of this Kshara taila on kotha roga.

Oligomer-assisted self-assembly of bisurea in organic solvent media.

We report on molecular dynamics simulation evidence revealing that an oligomer additive can be used to greatly facilitate the self-assembly of a bisurea in organic solvent media, through the initial regular packing and the subsequent stiffening of the self-assembly filament. The underlying physics is attributed to the substantially reduced diffusivities of the solute and, in particular, solvent molecules, featuring a generally weakened (thermal) Brownian force under ambient conditions. Without such oligomer-induced molecular cooling-in contrast to the usual external cooling, the original solvent medium is noted to foster instead more stabilized and disordered aggregates and, in particular, it would require a temperature reduction that is practically inaccessible in order to sustain similar stiffness of the self-assembly filament. These features, in accord with recent experimental observations, highlight the open opportunity of promoting the self-assembly of small functional molecules in general solvent media without requiring substantial changes of the system temperature, as is crucial for many practical applications including the biological/biomedical ones.

Microstructures Formation through Liquid‐Assisted Assembly of Functional Materials for High‐Performance Electronics

AbstractThe assembly of functional materials into microstructures, which extends unique features such as enlarged specific surface areas, effective conduction paths, higher material utilization ratios, and ordered alignment compared to continuous films, has gained prominence in various fields. Achieving high performance in electronics requires cooperation among building blocks, fabrication methods, and device design. However, the remaining challenge is obtaining highly regular and large‐scale patterns with controllable assembly methods while maximizing device performances. Manipulating functional materials with liquid assistance is a feasible approach to realizing controllable dewetting, regular molecule packing, and customized performances. This review focuses on the recent advances in preparing and applying liquid‐induced microstructures. The predominant preparation technologies are summarized, including flow‐enabled assembly, nanoimprint lithography, and capillary‐bridge‐mediated assembly. Furthermore, diverse applications of various microstructure‐based electronics, such as flexible and transparent electrodes, organic field‐effect transistors, gas sensors, photodetectors, and solar cells, are demonstrated.

Evaluation of Mechanical and Thermal Properties of Polypropylene-Based Nanocomposites Reinforced with Silica Nanofillers via Melt Processing Followed by Injection Molding

Polymer nanocomposites have been of great interest to packaging, energy, molding, and transportation industries due to several favorable properties including a higher resistance to stress and cracking even under flexed conditions, and also a chemical resistance to water, acids, and alkalis. The current work disseminates the studies on the mechanical and thermal properties of the polypropylene HHR102 polymer reinforced with nano dispersoids of silicon dioxide at varied weight fractions. The nanocomposites, fabricated via melt processing followed by injection molding, were tested for tensile strength, % elongation, tensile modulus, and impact toughness. Further, the samples were also subjected to dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) to determine the dynamic storage modulus and thermal stability. The addition of nano-silica in polypropylene HHR102 resulted in enhanced ductility and well-balanced tensile modulus; however, the tensile strength and impact toughness were found to be decreased. On the other hand, the storage modulus was significantly increased for all nano-silica (NS)-containing polypropylene HHR102 matrices. With the increased nano-silica content, the storage modulus was optimal. Further, with the lower weight loss of 30% and 50%, the thermal stability of the increased silica content PP nanocomposites was much affected. However, it improved at a weight loss of 30% for the lower silica content PP nanocomposite (PP-1%NS). The imbibition was found to increase with the increase in NS. The increase in imbibition is attributed to the micro-voids generated during ageing. These micro-voids act as channels for water absorption. Further, the degree of crystallinity of the nanocomposites was decreased as a result of inhibition by the nano-particles on the regular packing of polymer molecules. The structure–property correlations were explicated based on the achieved mechanical properties.

Zastosowanie programowania nieliniowego dla konfiguracji systemu wymiany ciepła w aparatach kolumnowych przemysłu petrochemicznego przy minimalnych kosztach

For increasing the efficiency of heat transfer processes, the layer-by-layer concept of arrangement of various types of packings in column apparatuses is considered. The results of hydraulic tests of a dry and irrigated cell packing, as well as individual hydraulic tests of a mesh packing, are presented. Methods and algorithms for solving linear programming problems under “uncertainty” conditions were considered. However, in some areas of science it is often difficult or impossible to formalize the problem in an appropriate way and reduce it to a linear programming problem. In this paper, methods for solving non-linear programming problems with a vector objective function are considered. At present, the use of non-linear programming in the vast majority of real situations is reduced to linear approximation models. Along with this, at a significant non-linearity, due to its specificity or influence on the nature of the model, it is necessary to apply optimization methods that are much more complex than, for example, the simplex method. However, the importance of non-linear programming is constantly increasing. This is due to the rapidly growing knowledge of managers and specialists in the use of mathematical models designed to prepare solutions, as well as the increasing availability of computer programs for solving large-scale nonlinear problems. The analysis and studies of the hydrodynamics of a number of regular packings have shown that cell and mesh packings are promising for the implementation of the phase inversion mode. The proposed concept of intensifying heat transfer processes in column apparatuses is based on the use of layers of various packings arranged in the following order in the apparatus, type 1 – cell, type 2 – mesh. At the same time, their main geometric characteristics differ significantly from each other. However, the structure of the bulk packing is inhomogeneous, which makes it difficult to implement a stable mode of local phase inversion under these conditions. This is due to the structure of column apparatuses with bulk packing, in which there is an increased proportion of pores (porosity) near the walls of the apparatus. Porosity is very significant; it can reach up to 40%, and as a result, the local velocity near the walls exceeds the velocity in the centre of the apparatus by up to 70%. By contrast, the use of regular packing structures makes this potentially highly efficient mode technically possible.

Flexural rigidity of pressurized model notochords in regular packing patterns

The biomechanics of embryonic notochords are studied using an elastic membrane model. An initial study varying internal pressure and stiffness ratio determines tension and geometric ratios as a function of internal pressure, membrane stiffness ratio, and cell packing pattern. A subsequent three-point bending study determines flexural rigidity as a function of internal pressure, configuration, and orientation. Flexural rigidity is found to be independent of membrane stiffness ratio. Controlling for number and volume of cells and their internal pressure, the eccentric staircase pattern of cell packing has more than double the flexural rigidity of the radially symmetric bamboo pattern. Moreover, the eccentric staircase pattern is found to be more than twice as stiff in lateral bending than in dorsoventral bending. This suggests a mechanical advantage to the eccentric WT staircase pattern of the embryonic notochord, over patterns with round cross-section.

Recycling PET Bottles for 3D-Printing Filament: Effect of Chain Extender

This study investigates the effect of a chain extender on the properties of recycled polyethylene terephthalate (rPET) for 3D printing filament. The research focuses on the melt flow index (MFI), mechanical properties, thermal behavior, and crystallinity of rPET blends with varying chain extender concentrations. MFI analysis reveals that the viscosity of rPET is influenced by the grade and sources of the PET bottles. The addition of the chain extender decreases MFI, indicating increased viscosity. Mechanical testing shows a slight decrease in impact strength with increasing chain extender concentration, suggesting the presence of limitations or constraints within the material. Thermal analysis demonstrates that the chain extender elevates the glass transition temperature (Tg) and melting temperature (Tm) of rPET, indicating enhanced rigidity and thermal resistance. However, the crystallinity (Xc) decreases as the chain extender disrupts the regular packing of polymer chains within the crystalline regions. These findings provide valuable insights into the influence of the chain extender on the properties of rPET for 3D printing filament. The research contributes to the development of sustainable manufacturing practices and promotes the utilization of recycled materials in additive manufacturing applications, furthering the goals of the circular economy and environmental sustainability.

Synthesis of Thermoplastic Mixed Chitin Esters.

Mixed chitin esters, that is, chitin benzoate stearates, exhibiting thermoplasticity, were synthesized by the acylation of chitin using benzoyl and stearoyl chlorides in the presence of pyridine and N,N-dimethyl-4-aminopyridine for 1 h + 24 h at 100 °C in an ionic liquid, 1-allyl-3-methylimidazolium bromide. IR and 1H NMR spectroscopic analyses confirmed the formation of the desired chitin benzoate stearates. Powder X-ray diffraction analysis of the products indicated that the crystalline structures of the chitin main-chains and stearoyl side-chains were strongly affected by the benzoyl/stearoyl substituent ratios. Introducing a small number of benzoyl groups, in addition to a large ratio of stearoyl groups, contributed to disrupting the intrinsic chitin crystals and enabling the chitin main chains and stearoyl side chains to form regularly controlled layered and parallel arrays, respectively. The resulting products exhibited meting points, associated with regular stearoyl packings, and formed melt-pressed films during the melt-pressing process. These results suggest that chitin benzoate stearates with appropriate benzoyl/stearoyl substituent ratios exhibit thermoplasticity.

Investigation of Pyrogas Cooling in a Packed Scrubber with a Regular Packing

Investigation of Pyrogas Cooling in a Packed Scrubber with a Regular Packing

Shape‐ and Size‐Tunable Synthesis of Covalent Organic Cages through Rh‐Catalyzed Regioselective [2+2+2] Cycloaddition

AbstractCovalent organic cages have potential applications in molecular inclusion/recognition and porous organic crystals. Bridging arene units with sp3 atoms enables facile construction of rigid isolated internal vacancies, and various prismatic arene cages have been synthesized by kinetically controlled covalent bond formation. However, the synthesis of a tetrahedral one, which requires twice as much bond formation as prismatic ones, has been limited to a thermodynamically controlled dynamic SNAr reaction, and this reversible covalent bond formation made the resulting cage product chemically unstable. Here we report the Rh‐catalyzed high‐yielding and highly 1,3,5‐selective room temperature [2+2+2] cycloaddition of push‐pull alkynes and its application to the synthesis of chemically stable aryl ether cages of various shapes and sizes, including prismatic and tetrahedral forms. These aryl ether cages are highly crystalline and intertwine with each other to form regular packing structures. Some aryl ether cages encapsulated isolated water molecules in their hydrophobic cavity by hydrogen bonding with the multiple ester moieties.

Experimental study of direct contact condensation of spent vapor in a cocurrent flow packed tower under negative pressure

AbstractCondensers are often required in power generation systems to condense the exhaust steam generated at the end of the turbine. This paper will investigate the enhanced condensation process of spent steam in a parallel flow type. The operating parameters of steam temperature (Tcond), steam flow rate (Gin), cooling water temperature (Tin), and cooling water flow rate (Lw) will affect the condensation effect by changing the gas–liquid arrangement in the tower. In this experiment, an orthogonal test was designed in the Raschig ring to investigate the significance of these four operating parameters on the experimental results. Different types of packings have different condensation effects due to different accumulation methods. The same type of packing has a different surface area, resulting in different contact areas between the gas and liquid phases during condensation. In this experiment, four different packings will be investigated to find their condensation performance. This paper uses the size of subcooling (ΔT) as an indicator to evaluate the effectiveness of condensation, and the values of condensation rate (R), number of liquid phase heat transfer units (NTUL), and total volume heat transfer coefficient (Kv) are used as a reference for the effectiveness of condensation. The results show that the overall condensation effect of regular packing is better than that of random packing, The average condensation rate of regular packing is 95%, the average condensation rate of random packing is 90%, the subcooling of regular packing is about three to five smaller than that of random packing, the heat transfer coefficient of regular packing is about 1.5 times of that of random packing. And by fitting the Kv data for different packings, an empirical formula was obtained that can be used to predict the Kv size of other packings.