Good Packing Research Articles

Stereologically corrected particle size distributions for polymer-mounted additive manufacturing powders

Well-defined particle size distributions are required for good flowability and powder packing properties of additive manufacturing powders. Mounting powders within a polymer and using standard metallurgical preparation techniques to cross-section and prepare powder particles for optical analysis allows for simple characterisation processes. However, measured diameters of cross-sectioned particles are typically underestimates of actual particle diameters and hence require stereological correction. The effectiveness of three stereological corrections are investigated in this work, namely the Scheil-Schwartz-Saltykov method, the Goldsmith-Cruz-Orive method and a Finite Difference Method. These methods are investigated against plasma-atomised, gas-atomised and ultrasonically processed Ti-6Al-4V powders. The corrected outputs are compared to laser size diffraction, benchmark data for each powder. Although all three stereological corrections produce improved estimations of the particle size distributions, the Finite Difference Method is recommended producing cumulative mean absolute error values of 2.4%, 3.1% and 7.5% for the plasma-atomised, gas-atomised and ultrasonically processed powders respectively.

Intrinsically Stretchable Polymer Semiconductor with Regional Conjugation for Stretchable Electronics

AbstractThe development of intrinsically stretchable polymer semiconductor holds substantial promise in the field of wearable electronics. However, charge transport mobility is typically compromised in existing stretchable semiconductors to achieve the desired stretchability. Herein, a novel “regional conjugation” strategy is proposed to design an intrinsically stretchable polymer semiconductor oligo‐diketopyrrolopyrrole‐thieno[3,2‐b]thiophene (DPPTT)–urethane, in which oligo‐DPPTT conjugated units and alkyl urethane nonconjugated units are introduced. The regional conjugation of oligo‐DPPTT in the polymer backbone endows DPPTT–urethane with good molecular packing, leading to a high mobility of up to 1.7 cm2 V−1 s−1. Additionally, incorporating alkyl urethane nonconjugated units in the backbone can reduce film crystallinity and chain aggregation, which contribute to the stretchability of the polymer thin film. Consequently, fully stretchable transistors retain carrier mobility even at 100% biaxial tensile strain. Furthermore, the fully stretchable organic field‐effect transistor arrays show remarkable charge transport reversibility and durability after 1000 stretch–release cycles at 25% strain. Additionally, the device exhibits extraordinary electrical stability in air atmosphere. Overall, these results indicate that the “regional conjugation” strategy provides an effective and promising methodology to design intrinsically stretchable and high‐performance polymer semiconductor that can advance the development of soft and wearable electronics.

Network pharmacology, molecular simulation, and binding free energy calculation-based investigation of Neosetophomone B revealed key targets for the treatment of cancer.

In the current study, Neosetophomone B (NSP-B) was investigated for its anti-cancerous potential using network pharmacology, quantum polarized ligand docking, molecular simulation, and binding free energy calculation. Using SwissTarget prediction, and Superpred, the molecular targets for NSP-B were predicted while cancer-associated genes were obtained from DisGeNet. Among the total predicted proteins, only 25 were reported to overlap with the disease-associated genes. A protein-protein interaction network was constructed by using Cytoscape and STRING databases. MCODE was used to detect the densely connected subnetworks which revealed three sub-clusters. Cytohubba predicted four targets, i.e., fibroblast growth factor , FGF20, FGF22, and FGF23 as hub genes. Molecular docking of NSP-B based on a quantum-polarized docking approach with FGF6, FGF20, FGF22, and FGF23 revealed stronger interactions with the key hotspot residues. Moreover, molecular simulation revealed a stable dynamic behavior, good structural packing, and residues' flexibility of each complex. Hydrogen bonding in each complex was also observed to be above the minimum. In addition, the binding free energy was calculated using the MM/GBSA (Molecular Mechanics/Generalized Born Surface Area) and MM/PBSA (Molecular Mechanics/Poisson-Boltzmann Surface Area) approaches. The total binding free energy calculated using the MM/GBSA approach revealed values of -36.85kcal/mol for the FGF6-NSP-B complex, -43.87kcal/mol for the FGF20-NSP-B complex, and -37.42kcal/mol for the FGF22-NSP-B complex, and -41.91kcal/mol for the FGF23-NSP-B complex. The total binding free energy calculated using the MM/PBSA approach showed values of -30.05kcal/mol for the FGF6-NSP-B complex, -39.62kcal/mol for the FGF20-NSP-B complex, -34.89kcal/mol for the FGF22-NSP-B complex, and -37.18kcal/mol for the FGF23-NSP-B complex. These findings underscore the promising potential of NSP-B against FGF6, FGF20, FGF22, and FGF23, which are reported to be essential for cancer signaling. These results significantly bolster the potential of NSP-B as a promising candidate for cancer therapy.

Water Reduction of Biodegradable Plastic From Bagasse By‐Product With Synergistic Effect of Graphene Oxide Reinforcement and Citric Acid Crosslinking

In today’s world, plastics are vital as they are used in a wide range of applications although packaging is the most prevalent. Most of the plastics that are used for packaging applications are derived from petrochemicals. These plastics meet most of the requirements for good packing applications. However, they are not completely biodegradable. This consequently pollutes the environment. As a result, biodegradable plastics have emerged as an alternative to conventional plastics. Cellulose is one of the potential materials that are used for making biodegradable plastics. However, making plastic from cellulose causes deforestation. In this work, plastic was produced from cellulose bagasse, which is an industrial waste. Since bagasse is an industrial by‐product, it causes neither deforestation nor scarcity of food. However, the plastic made from bagasse showed high water absorption and low tensile strength. To overcome this problem, the plastic, which is made from bagasse, was reinforced with various concentrations of graphene oxide (GO) and crosslinked with various concentrations of citric acid (CA) at different crosslinking temperatures and crosslinking times. The water absorption and biodegradability of the films were studied. Furthermore, the synergistic effect of crosslinking and reinforcement was used to improve the interfacial bonding between the two. The water absorption of pure cellulose, cellulose crosslinked with 10% CA, cellulose reinforced with 15% GO reinforcement, and synergy of 10% CA crosslinking and 15% GO reinforcement at crosslinking temperature of 130°C and crosslinking time of 25 min was found to be 99.02%, 56.4%, 44.275%, and 36.78%, respectively. The biodegradability at the optimal values of crosslinker concentration, crosslinking time, and crosslinking temperature of pure cellulose of bagasse, 10% CA crosslinked bagasse, and 10% CA crosslinked bagasse with 15% GO reinforcement in 30 days were found to be 94.0397%, 56.91%, and 40.81%, respectively. The result of the study shows that water‐resistant biodegradable plastic can be produced with the synergistic effect of crosslinking and reinforcement.

Comparative Evaluation of Formulations Designed using Chemically Modified Pectin and Eudragit for Sustained Release of Nateglinide

The present work was proposed to chemically modified Pectin with its hydrophilicity reduced and potential for being an universal excipient. The Bulk densities of NTGT granules were found to be 0.3473 which indicate good packing capacity. Carr’s index of NTGT granules were found to be 5.88 which indicate excellent flow properties. Hausner ratio of NTGT granules were found to be 1.0621. Angle of repose of NTGT granules were excellent flow properties. The formulations MP1P2 after optimization to limit the release in the first 3 hrs could also be equally effective. Comparative evaluation of the designed formulations, the release of nateglinide from tablets coated with eudragit RL100 was progressively prolonged, as concentration of eudragit in the coating solution was increased about 63.91% at 12hr of NTGEUD3 batch. The formulated batches gives a clear indication that once daily formulations of nateglinide as oral hypoglycemics drug can be designed using this approach and subsequent release at a consistently uniform rate for sustained action has been achieved.

Thickness Tolerance in Large-Area Organic Photovoltaics with Fluorine-Substituted Regioregular Conjugated Polymer.

Large areas and simple processing methods are necessary for the commercialization of organic photovoltaics (OPVs). However, the efficiency drop due to the variation in thickness of OPVs limits their large-scale applications. Regioregular polymers with good crystallinity and packing properties that exhibit high charge mobility and extraction ability can help overcome these limitations. In this study, a regioregular polymer named PDBD-2FBT was synthesized. The crystallinity and packing properties of PDBD-2FBT were enhanced by a simple thermal treatment. Using PDBD-2FBT material as a donor and Y6-HU as an acceptor, we fabricated binary blend OPV devices. The devices with optimized active layer thickness achieved a power conversion efficiency (PCE) of 14.14%. A PCE of 13.18% was maintained even in thick-film conditions (400 nm), and thickness tolerance was observed. Based on the thickness tolerance, a 5-line module measuring 36 cm2 was fabricated via the bar-coating method, and a PCE of approximately 10% was achieved.

Influence of filler/cement and powder/total solids on the mixture design of self-compacting micro-concretes containing waste from the ornamental stone industry

The present work evaluated the effects of incorporating high volumes of waste from the processing of ornamental stones as fillers in self-compacting micro-concretes, considering physical–chemical, mechanical, microstructural and eco-efficiency results. A particle packing method assisted in the mix designs, and the experimental program followed a central composite rotational statistical design. Response surfaces and desirability analyses showed that the residue has a good packing function, filler effect, heterogeneous nucleation and workability, in addition to being effective in reducing the embodied CO2, delivering matrices more eco-efficient for conventional mechanical strengths.

Productivity Decline Mechanisms in Gravel Packed Perforations

In a cased hole gravel pack completion, perforations are packed with proppant to both mechanically support the perforation cavity, and to filter any produced sand before it reaches the surface. Poor perforation packing sometimes occurs in which the perforation is partially or completely unsupported, leading to earlier productivity reduction than in cases of good packing. We investigated productivity reduction and the associated mechanisms in a series of hollow cylinder experiments on outcrop and field cores with varying proppant packing. Packed perforations maintained significantly higher productivity than unsupported perforations by preventing macroscopic shear failure around the cavity and erosion due to sand production. Partial packing may in some instances maintain productivity almost as well as complete packing, but this likely depends on perforation orientation. Compaction tests and numerical simulations suggest that compaction failure is unlikely at the cavity wall in the current experiments, and that proppant-formation interface damage or proppant filtering of produced sand are more probable explanations for the productivity reduction seen in packed perforations.

Investigation and assessment of epoxy resin adhesives using Fourier‐transform infrared spectrometry

AbstractEpoxy resin adhesives are very attractive for many industries, especially in the aerospace and automotive industries because they eliminate heavy connection elements, such as bolts and screws, and reduce the total weight. This study assesses developed epoxy resin adhesives using Fourier‐transform infrared spectrometry. The curing reaction between Epikote 828 epoxy resin and Epikure polyamidoamine curing agent 3090, and the chemical structure of the additives (CAB‐O‐SIL TS‐720) used for rheology control and six different types of fillers (calcite with particle diameters of 700 nm, 5 μm, and 10 μm, coated calcite with a particle diameter of 900 nm, and barite and calcite with a particle diameter of 5 μm) employed in the adhesives are investigated. The Fourier‐transform infrared spectrometry results of the epoxy resin and curing agent demonstrate that 83.5 % epoxy conversion is achieved at a temperature of 25 °C. The chemical composition of the additives with six different types of fillers and 1 %, 3 %, and 5 % additions of CAB‐O‐SIL TS‐720 prepared in both nujol mull and potassium bromide discs is characterized using Fourier‐transform infrared spectrometry. The potassium bromide discs yield higher intensities owing to good packing of cubic particles of potassium bromide with nano particle size CAB‐O‐SIL TS‐720 and all filler types.

Efficient ternary WORM memory devices from quinoline-based D-A systems by varying the redox behavior of ferrocene.

The design and synthesis of ferrocene-functionalized organic small molecules using quinoline cores are rendered to achieve a ternary write-once-read-many (WORM) memory device. Introducing an electron-withdrawing group into the ferrocene system changes the compounds' photophysical, electrochemical, and memory behavior. The compounds were synthesized with and without an acetylene bridge between the ferrocene unit and quinoline. The electrochemical studies proved the oxidation behavior with a slightly less intense reduction peak of the ferrocene unit, demonstrating that quinolines have more reducing properties than ferrocene with bandgaps ranging from 2.67-2.75 eV. The single crystal analysis of the compounds also revealed good interactive interactions, ensuring good molecular packing. This further leads to a ternary WORM memory with oxidation of the ferrocene units and charge transfer in the compounds. The devices exhibit on/off ratios of 104 and very low threshold voltages of -0.58/-1.02 V with stabilities of 103 s and 100 cycles of all the states through retention and endurance tests.

A Novel Hexagonal Psuedo framework for Edge Detection Operators on Hexagonal Framework

Edge detection using a gradient-based detector is a gold-standard method for identifying and analyzing different edge points in an image. A hexagonal grid structure is a powerful architecture dominant for intelligent human-computer vision. This structure provides the best angle resolution, good packing density, high sampling efficiency, equidistant pixels, and consistent connectivity. Edge detection application on hexagonal framework provides more accurate and efficient computations. All the real-time hardware devices available capture and display images in rectangular-shaped pixels. So, an alternative approach to mimic hexagonal pixels using software approaches is modeled in this paper. In this research work, an innovative method to create a pseudo hexagonal lattice has been simulated and the performance is compared with various edge detection operators on the hexagonal framework by comparing the quantitative and qualitative metrics of the grayscale image in both square and hexagonal lattice. The quantitative performance of the edge detection on the hexagonal framework is compared based on the experimental facts. The pseudo-hexagonal lattice structure assures to be aligned toward the human vision.

Multifaceted Sulfone-Carbazole-Based D-A-D Materials: A Blue Fluorescent Emitter as a Host for Phosphorescent OLEDs and Triplet-Triplet Annihilation Up-Conversion Electroluminescence.

Electroluminescence (EL) from the singlet-excited (S1) state is the ideal choice for stable, high-performing deep-blue organic light-emitting diodes (OLEDs) owing to the advantages of an adequately short radiative lifetime, improved device durability, and low cost, which are the most important criteria for their commercialization. Herein, we present the design and synthesis of three donor-acceptor-donor (D-A-D)-configured deep-blue fluorescent materials (denoted as TC-1, TC-2, and TC-3) composed of a thioxanthone or diphenyl sulfonyl acceptor and phenyl carbazolyl donor. These systems exhibit strong deep-blue photoluminescence (422-432 nm) in solutions and redshifted emission (472-486 nm) in thin films. The solid-state photoluminescence quantum yield (PLQY) was estimated to be 78 and 94% for TC-2 and TC-3, respectively. TC-2 and TC-3 possess good molecular packing and large molecular cross-sectional areas, which not only improves the PLQY but enhances the triplet-triplet annihilation up-conversion (TTAUC) efficiency of fluorescent emitters. Furthermore, both compounds were applied as an acceptor for confirming their TTAUC property using bis(2-methyldibenzo[f,h]quinoxaline)(acetylacetonate)iridium(III) (Ir(MDQ)2acac) as the sensitizer. Non-doped OLEDs based on TC-2 and TC-3 exhibit blue EL in the 461-476 nm range. In particular, TC-3 exhibits a maximum external quantum efficiency (EQEmax) of 5.1%, and its EL maximum is 476 nm. In addition, the three emitters were employed as hosts in red OLEDs using bis(1-phenylisoquinoline)(acetylacetonate)iridium(III) (Ir(piq)2acac) as the phosphorescent dopant. The red phosphorescent OLEDs based on TC-1, TC-2, and TC-3 achieve excellent EQEmax values of 21.6, 22.9, and 21.9%, respectively, and peak luminance efficiencies of 12.0, 14.0, and 12.3 cd A-1. These results highlight these fluorophores' versatility and promising prospects in practical OLED applications.

Lattice packings through division algebras

In this text, we will show the existence of lattice packings in a family of dimensions by employing division algebras. This construction is a generalization of Venkatesh’s lattice packing result Venkatesh (Int Math Res Notices 2013(7): 1628–1642, 2013). In our construction, we replace the appearance of the cyclotomic number field with a division algebra over the rational field. We employ a probabilistic argument to show the existence of lattices in certain dimensions with good packing densities. The approach improves the best known lower bounds on the lattice packing problem for certain dimensions.We work with a moduli space of lattices that are invariant under the action of a finite group, one that can be embedded inside a division algebra. To obtain our existence result, we prove a division algebra variant of the Siegel’s mean value theorem. In order to establish this, we describe a useful description of the Haar measure on our moduli space and a coarse fundamental domain to perform the integration.

Microcatheter-guided compartment packing of acutely ruptured complex intracerebral aneurysms (ARCIAs): Preliminary experience and technical note.

We present our initial experience using the microcatheter-guided compartment packing (MCP) technique for endovascular embolization of acutely ruptured complex intracerebral aneurysms (ARCIAs) and evaluate the safety, feasibility, and efficiency of this technique. This retrospective, single-center study included 28 patients who underwent coil embolization using the MCP technique for ARCIAs at our institution between January 2021 and January 2022. The MCP technique was the placement of microcatheters in different compartments within the aneurysm to deploy the coils simultaneously or sequentially. Patient demographics, aneurysm characteristics, procedural parameters, grade of occlusion, complications, and clinical results were analyzed. The clinical outcomes were evaluated with modified Rankin Scale (mRS) scores. Of the 28 patients successfully treated with the MCP technique, 24 (85.7%) aneurysms were considered as complete occlusions (Raymond I) based on the immediate postembolization angiogram results. Complications occurred in 2/28 treatments, including guidewire perforation with subarachnoid hemorrhage and cerebral vasospasm-related cerebral infarction. An angiography follow-up demonstrated complete occlusion in 25/28 aneurysms. Twenty-six (92.9%) patients had favorable 90-day outcomes (mRS 0-2) after the endovascular coil embolization. The MCP technique is simple, safe, and effective, achieving good packing density and initial occlusion rate when used to treat ARCIAs.

Computational screening of natural products to identify potential inhibitors for human neuropilin-1 (NRP1) receptor to abrogate the binding of SARS-CoV-2 and host cell

Recently, a new variant B.1.1.529 or Omicron variant and its sub-variants (BA2.75, BA.5) of SARS-CoV-2 (Severe acute respiratory virus 2) have been reported with a larger number of mutations in the spike protein and particularly in the RBD (receptor-binding domain). The omicron (B.1.1.529) variant has aggravated the pandemic situation further and needs more analysis for therapeutic development. Keeping in view the urgency of the required data, the current study used molecular modeling and simulation-based methods to target the NRP1 (Neuropilin 1) protein to halt the entry into the host cell. Employing a molecular screening approach to screen the North-East African natural compounds database (NEANCDB) revealed Subereamine B with a docking score of −8.44 kcal/mol, Zinolol with the docking score of −8.05 while Subereamine A with a docking score of −7.88 kcal/mol as the best hits against NRP1. Molecular simulation-based further validation revealed stable dynamics, good structural packing, and dynamic residues flexibility index. Moreover, hydrogen bonding fraction analysis demonstrated the interactions remained sustained during the simulation. Furthermore, the total binding free energy for Subereamine B was −44.24 ±0.91 kcal/mol, for Zinolol −34.32 ±0.40 kcal/mol while for Subereamine A the TBE was calculated to be −41.78 ± 0.36 kcal/mol respectively. This shows that the two arginine-based alkaloids, i.e. Subereamine B and Subereamine A could inhibit the NRP1 more strongly than Zinolol. In conclusion, this study provides a basis for the development of novel drugs against SARS-CoV-2. Communicated by Ramaswamy H. Sarma

Carbon nanotube deposition through intermittent high voltage pulsed electrophoresis on jute fibre

Electrophoretic deposition is an efficient, high-level process for the manufacture of films or coatings from colloidal suspensions. In this process, electrophoretically deposited materials exhibit good microstructure homogeneity and high packing density. The effect of Carbon Nanotubes (CNT) deposition through intermittent high voltage Electrophoretic Deposition (EDP) on the Jute Fibre (JF) surface is analysed. This is a method adapted from the conventional EDP process. Therefore, two parameters, such as pulse type and medium type, are evaluated to obtain an effective and uniform CNT deposition on the JF surface. The pulse types are positive pulse discharge and positive and negative pulse discharge. Both pulses are intermittent and delivered at high voltages. On the other hand, two medium types were considered. The first is composed of CNT and deionized water, and the other is composed of CNT, Sodium Dodecyl Sulfate (SDS), and deionized water. According to the microscopy results and TG, it is clear that the introduction of SDS on the medium, under positive and negative pulse discharge, provided an effective and homogeneous CNT deposition onto the JF surface. As a result of good CNT deposition, it was an enhancement in electrical conductivity and an increase in oxygen functional groups compared to untreated JF. Also, the JF became hydrophobic.

Formulation development and evaluation of novel polyherbal tablet with complete antidiabetic solution

Four herbal drugs with the complete antidiabetic solution were selected based on documented properties. Poly-herbal combinations containing 50 % hydro-alcoholic extracts, having the most significant overall antidiabetic activity were selected and polyherbal uncoated tablet (PHUT) was developed. 500 mg PHUT were developed, by homogeneously mixing 250 mg/tablet, dried and finely powdered extracts of four herbs in the most effective ratio, i.e. H. sabdariffa (100): A. marmelos (50): F. religiosa (75): A. squamosa (25), with excipients (250 mg/tablet) by direct compression method. For formulation optimization, 3 different formulations were developed by using the same excipients in different ratios and were evaluated for good flow properties and good packing ability. After pre-compression studies, powdered blends were directly compressed and were evaluated using post-compression parameters. Developed PHUTs were dark reddish-brown and devoid of any rough surface. Post compression parameters showed that all parameters are within the limit for all PHUT formulations. Out of all, PHUT 3 showed a significant average disintegration time of 9.40 minutes; hence it was considered as an optimized formulation and was subjected to 3 months accelerated stability studies. Where no significant changes were observed, PHUT 3 was considered a standard formulation with a complete antidiabetic solution.

Achieving High-Performance Molecular Rectification through Fast Screening Alkanethiol Carboxylate-Metal Complexes Electroactive Units

Achieving High-Performance Molecular Rectification through Fast Screening Alkanethiol Carboxylate-Metal Complexes Electroactive Units

Phase diagram and mechanics of snap-folding of ring origami by twisting

Ring origami is a new strategy to design bistable foldable/deployable structures by assembling multiple rings with the same geometry. The successful folding of ring origami assembly leverages the snap-folding capability of single rings. It is thus important to model the snap-folding of ring-shaped structures for the rational design of ring origami with good foldability, stability and high areal packing ratio. This paper studies the folding mechanics of differently shaped rings (circular, elliptical, rounded rectangular and rounded triangular rings) under twisting loads by developing theoretical and three-dimensional finite element analysis (FEA) models. The rod model is re-formulated for different ring geometries as two-point boundary value problem systems, which are then solved through numerical continuation, allowing one to capture complex equilibrium paths with multiple fold points. The rod model, verified by FEA simulations and experiments, can accurately, quantitatively capture the snap-folding behaviors for rings of different geometries. Using the rod model, we analyze the folding modes in terms of foldability, stability and snapping type. Phase diagrams of folding modes are then constructed with respect to geometric parameters for the ring profile and cross-section for differently shaped rings. Diagrams of areal packing ratios are obtained using the reduced planar rod model. This work provides comprehensive mechanics insights into the ring folding through twisting and can guide future ring origami design.

CT-based method to measure metal powder characteristics and to study their influence on the quality of additively manufactured parts

Laser powder bed fusion (LPBF) is increasingly used to produce metal industrial components for high value-added sectors, such as aerospace, automotive and biomedical. However, mechanical and structural properties of LPBF parts are often hindered by the large quality variability, poor geometrical and dimensional characteristics, complex surface texture and low density. The quality of the feedstock material is an important aspect to be taken into account, as it significantly influences such possible issues. In particular, metal powder used in LPBF should have shape and size distribution designed to facilitate good flowability, spreading and packing behaviour, so that the final fabricated parts have acceptable density, surface finish and mechanical properties. This work focuses on the accuracy of simultaneous measurement of powder size and shape from three-dimensional reconstructions obtained by X-ray computed tomography (CT). Results of CT measurements are compared with results from other methods based on laser diffraction and scanning electron microscopy. Different materials and powder morphologies were investigated. In addition, the CT-measured powder characteristics can be used to improve other CT analyses of LPBF parts.