Fuzzy Balls Research Articles

Isospectral graphs via spectral bracketing

In this article, we develop a perturbative technique to construct families of non-isomorphic discrete graphs which are isospectral for the standard (also called normalised) Laplacian and its signless version. We use vertex contractions as a graph perturbation and spectral bracketing with auxiliary graphs which have certain eigenvalues with high multiplicity. There is no need to know explicitly the eigenfunctions of the corresponding graphs. In principle, one only needs to know the multiplicity of the eigenvalues of the auxiliary graphs, and that these eigenvalues are all different. We illustrate the method by presenting several families of examples of isospectral graphs including fuzzy balls, complete bipartite graphs and subdivision graphs obtained from the previous examples. All the examples constructed turn out to be also isospectral for the standard (Kirchhoff) Laplacian on the associated equilateral metric graph.

Experimental and EOR Mechanism Study of Water Shutoff Effects on Fractured Tight Sand Gas Reservoirs Using Fuzzy Ball Fluids

In recent years, there has been quite a dispute over the water shutoff effect of fuzzy ball fluids in fractured tight sandstone gas reservoirs. The core issue of this dispute is to try and make fuzzy ball fluid stabilize gas during the water shutoff process for sustainable development. In order to solve this dispute, the Linxing He-2 reservoir matrix core and a core with artificial fractures were used to simulate interlayer water, artificial fractures, and water output channels from the side and bottom. Simulated formation water and nitrogen were used as the two-phase flow phase. The breakthrough pressure of the air and water phases was tested after plugging with fuzzy ball fluid in order to simulate and analyze the water shutoff effect of the fuzzy ball fluid and its ability to achieve air establishment and water control. The results of this study show that for the core matrix, the breakthrough pressure gradient for water and gas varied from 0.200 MPa/cm to 0.210 MPa/cm and 0.015 MPa/cm to 0.025 MPa/cm, and for artificial fractured cores, the breakthrough pressure gradient of water and gas varied from 0.035 MPa/cm to 0.040 MPa/cm and 0.015 MPa/cm to 0.020 MPa/cm. These results prove that fuzzy ball fluid can block small-scale water output channels, such as matrix pores, through the polymer film-forming structure, and plug the artistic cracks and large-scale water output channels of the water flowing into the sides and bottom through the accumulation of a large number of fuzzy balls, which greatly improves the flow resistance of water. The amount of fuzzy ball fluid should be carefully adjusted with consideration of the water output and formation conditions. For large-scale water output channels and side and bottom water shutoff operations, it is recommended that the amount of fuzzy balls be increased along with the number of fuzzy balls in the system in order to increase the breakthrough pressure of water and achieve the stable control of air and water. It is believed that the fuzzy balls would quickly change their shapes to match the sizes of fracture channels to enter into fractured reservoirs and that an active hydrophobic membrane would form on the surface of fractured rocks, with macromolecules and surfactants being dispersed in the fluid system. In addition, the interface between the fuzzy balls is also hydrophobic, which would slow down the flow of water and provide a continuous gas percolating channel after aggregating and entering into the fractures. This increases the persistence of water intruding into the formation and does not affect the percolation of the gas of fractured tight sandstone gas reservoirs. This research is of great significance for the EOR of tight sand gas reservoirs and the sustainable development of oil and gas resources in China.

Distinguishing cospectral quantum graphs by scattering

We propose a simple method for resolution of cospectrality of Schrödinger operators on metric graphs. Our approach consists of attaching a lead to them and comparing the S-functions of the corresponding scattering problems on these (non-compact) graphs. We show that in several cases—including general graphs on at most six vertices, general trees on at most nine vertices, and general fuzzy balls—eigenvalues and scattering data are together sufficient to distinguish cospectral metric graphs.

Enhancing the production of tight sandstone gas well through fuzzy-ball fluid temporary plugging with diverting fractures and water cutting after refracturing in one operation

Refracturing is one of the most effective techniques to enhance the production of tight sandstone gas (TSG) well. Many TSG gas wells are facing the problem of water invasion after refracturing, the formation water may gradually occupy the gas-producing channels, preventing high gas productivity. In this paper, we newly developed a fuzzy-ball temporary plugging fluid (FTPF) with diverting fractures and water cutting after refracturing in one operation. The temporary plugging and water breakthrough control capabilities of the FTPF system were evaluated through the true triaxial large-scale core diversion fracturing experiment and matrix core and artificial fracture waterproof experiments. Meanwhile, the permeability damage evaluation experiments were performed to analyze the reservoir recovery ability. Results showed that the pressure-bearing capacity could reach up to 62.6 MPa, the rock fracture pressure was increased by 5–10 MPa compared with the initial hydraulic fracturing and an apparent fracture network structure was formed after refracturing. The breakthrough pressure gradients of simulated formation water were 2–10 times higher than that of nitrogen after the cores (including matrix and cores with 4 mm fractures) were plugged with FTPF, indicating its good water cutting ability. Before and after gel breaking, the permeability recovery value of the matrix core and the artificial fracture core was about 85–98%. The on-site application of FTPF to the refracturing of two TSG wells in the Sulige Gas Field in Northwest of China displayed that the average gas production has been enhanced by 64.8%. It is proposed that fuzzy balls can easily enter and gather at the tip of the initial fractures and form a stable pressure-bearing structure due to its viscoelastic properties and deformability. In addition, the hydrophilic fuzzy-ball core agents can adsorb on the rock's surface and form a polymer membrane, increasing the resistance of water flow.

Social-emotional learning and class climate among elementary-aged students in Japan

ABSTRACT This quasi-experimental, mixed methods study explored student perceptions of class climate before and after implementation of a two-week social and emotional learning (SEL) intervention in elementary classrooms in Japan. The sample consisted of 131 second and third grade students. A one-time SEL lesson focusing on offering kind words to peers was implemented in three classrooms. This was followed by two weeks of reinforcement, in which students were reinforced each time they offered kind words to a peer. One classroom used a sticker chart as the reinforcement and two classrooms filled up a jar with fuzzy balls. One classroom served as the control. Pre and post surveys were administered to students at the beginning and end of the intervention and teachers completed a survey at the end of the intervention. One-way ANOVA, t-test, and qualitative analyses revealed a significant improvement in class climate, in particular, sense of classroom orderliness, for the classrooms that used fuzzy balls as the reinforcement. Teacher feedback on the implementation of the SEL intervention included both positive and constructive reflections. These results may be considered for the development of SEL curricula to enhance its utility and effectiveness for East Asian student populations.

Must Have Been A Lie

Must Have Been A Lie

Structure and activity of human surfactant protein D from different natural sources.

Surfactant protein D (SP-D) is a C-type lectin that participates in the innate immune defense of lungs. It binds pathogens through its carbohydrate recognition domain in a calcium-dependent manner. Human surfactant protein D (hSP-D) has been routinely obtained from bronchoalveolar lavage of patients suffering from pulmonary alveolar proteinosis (PAP) and from amniotic fluid (AF). As a consequence of the disease, hSP-D obtained from PAP is found in higher amounts and is mainly composed of higher order oligomeric forms. However, PAP-hSP-D has never been directly compared with nonpathological human protein in terms of structure and biological activity. Moreover, the quantitative distribution of the different hSP-D oligomeric forms in human protein obtained from a natural source has never been evaluated. In this work, we have determined the quantitative distribution of AF-hSP-D oligomers, characterized the sugars attached through the N-glycosylation site of the protein, and compared the activity of hSP-D from AF and PAP with respect to their ability to bind and agglutinate bacteria. We have found that fuzzy balls (40%) are the most abundant oligomeric form in AF-hSP-D, very closely followed by dodecamers (33%), with both together constituting 73% of the protein mass. The glycan attached to the N-glycosylation site was found to be composed of fucose, galactose, sialic acid, and N-acetylglucosamine. Finally, in the functional assays performed, hSP-D obtained from PAP showed higher potency, probably as a consequence of its higher proportion of large oligomers compared with hSP-D from AF.

Functional characterization of the different oligomeric forms of human surfactant protein SP-D

Surfactant Protein D (SP-D) is a collectin protein that participates in the innate immune defense of the lungs. SP-D mediates the clearance of invading microorganisms by opsonization, aggregation or direct killing, which are lately removed by macrophages.SP-D is found as a mixture of trimers, hexamers, dodecamers and higher order oligomers, “fuzzy balls”. However, it is unknown whether there are differences between these oligomeric forms in functions, activity or potency.In the present work, we have obtained fractions enriched in trimers, hexamers and fuzzy balls of full-length recombinant human (rh) SP-D by size exclusion chromatography, in a sufficient amount to perform functional assays. We have evaluated the differences in protein lectin-dependent activity relative to aggregation and binding to E. coli, one of the ligands of SP-D in vivo. Fuzzy balls are the most active oligomeric form in terms of binding and aggregation of bacteria, achieving 2-fold binding higher than hexamers and 50% bacteria aggregation at very short times. Hexamers, recently described as a defined oligomeric form of the protein, have never been isolated or tested in terms of protein activity. rhSP-D hexamers efficiently bind and aggregate bacteria, achieving 50–60% aggregation at final time point and high protein concentrations. Nevertheless, trimers are not able to aggregate bacteria, although they bind to them. Therefore, SP-D potency, in functions that relay on the C-lectin activity of the protein, is proportional to the oligomeric state of the protein.

Structural Characterization of Human Pulmonary Surfactant Protein SP-D by Atomic Force Microscopy

Pulmonary surfactant protein D (SP-D), a C-type (Ca2+-dependent) lectin, belongs to the collectin family. It is found mainly in lung surfactant, participating in the innate immune defense of the lungs.SP-D monomer contains four structural domains: an N-terminus domain, a collagen region, an α-helical coiled-coil neck and a C-terminus carbohydrate recognition domain (CRD). Monomers form trimers through folding of the collagenous region into triple helices and the assembly of a coiled-coil bundle of α-helices in the neck region. These trimers are stabilized by two disulfide bonds in the cysteine-rich N-terminal domain. Trimers associate into higher order oligomers whose size and conformation is sensitive to environmental factors and the conditions during purification and storage. Despite extensive studies carried out to characterize the oligomerization process of SP-D, the pathway and type of interactions involved in the formation of large oligomers, are not clearly understood. In the current study, a structural characterization of recombinant human SP-D (rhSP-D), produced in mammalian CHO cells, has been carried out by Atomic Force Microscopy (AFM) and electrophoresis. The goal has been the determination of the distribution of oligomeric forms, the exploration of the possible oligomerization pathway and the description of the conformational diversity of rhSP-D. AFM experiments revealed that rhSP-D is a mixture of trimers, hexamers, dodecamers, and larger oligomeric species identified as “fuzzy balls”, with the most abundant structure being the dodecamer under the conditions of these experiments. We have developed a cross-linking protocol to detect the presence of SP-D dodecameric forms by PAGE-SDS, in which dodecamer is only visualized after chemical crosslinking and in the presence of denaturing agents, indicating the importance of hydrophobic interactions in dodecamer formation.

Effect of the fabric color on the visual perception of pilling

Purpose Pilling is a fabric surface fault comprising of small, fuzzy balls on the surface of a fabric that leads to poor handle and quality. The purpose of this paper is to investigate the effect of the fabric color in terms of depth and hue on the visual perception of pilling on the fabric surface. Design/methodology/approach Acrylic fabrics were prepared at various color depths and hues and then were applied with relatively equal amount of pilling on the surface of samples. The amount of perceived pilling was evaluated by human observers by employing paired comparison method and the results were analyzed using statistical methods. Findings According to the results, color depth and the visual perception of pilling in achromatic sample were nearly independent. Color hue can be considered as an important factor in the visual perception of pilling so when the color contrast between the pill and background decreases, the visual perception of pilling decreases as well. Hence, the achromatic sample have the most amount of pilling perception whereas green and blue samples show less pilling, in visual sensation. Originality/value There is a strong demand for acrylic fabrics in apparel industry but they have high tendency for pilling formation. To overcome this problem, experts have suggested some methods to prevent or reduce pilling. If it is proved that color influences on pilling perception, an useful instruction will be available for acrylic fabric manufacturers in order to satisfy their customer with good quality of products. In this work, the authors tried to find such relationships between the color and the pilling perception for human observers.

Predicting Equivalent Static Density of Fuzzy Ball Drilling Fluid by BP Artificial Neutral Network

A back-propagation artificial neutral network model is built based on 220 groups of PVT experimental data to predict the equivalent static density versus depth for fuzzy ball drilling fluid which is a kind of gas-liquid two-phase material. The model is applied in the Mo80-C well located in Sichuan Province of China; the maximum relative error between calculated results and measured data is less than 2%. By comparing with the multiple regression model, the present model has a higher precision and flexibility. The equivalent static density of fuzzy ball drilling fluid from ground to the depth of 6000 m is predicted by the present model, and the results show that the equivalent static density of fuzzy ball drilling fluid will decrease slowly with the growth of depth, which indicates that the gas cores of the fuzzy balls still can exist as deep as 6000 m.

On fuzzy soft metric spaces

In this paper an idea of fuzzy soft point is introduced and using it fuzzy soft metric space is established. The concepts like fuzzy soft open balls and fuzzy soft closed balls are introduced. Some properties of fuzzy soft metric spaces are developed.

Fuzzy Ball Drilling Fluid for CBM in the Ordos Basin of China

Fuzzy ball drilling fluids have been developed in order to effectively control lost circulation during CBM drilling. Depending upon fuzzy balls and colloids in fuzzy balls, the fuzzy ball drilling fluids changed their shapes and properties to completely plug underground heterogeneous seepage channels so as to strengthen the pressure bearing capacity of formations. This paper describes the available features of the fuzzy ball drilling fluid including efficient plugging, good carrying and suspension, formation damage control, compatible weighted by any weighted materials without auxiliary equipment. The fuzzy ball drilling fluids can finish drilling in low pressure natural gas zone, control CBM leakage; control the natural fractures, drilling in different pressures in the same open hole, combination with the air drilling mode, etc. during Ordos CBM drilling. The fuzzy ball drilling fluid will not affect down-hole motors and MWD. The fuzzy ball drilling fluid will be blend simply as conventional water based drilling fluids. The existing CBM drilling equipment can completely meet the fuzzy ball drilling mixing and it is maintained conveniently. The fuzzy ball drilling fluid is the efficient drilling fluid.

Fuzzy Ball Drilling Fluids for CBM in the Ordos Basin of China

Fuzzy ball drilling fluids have been developed in order to effectively control lost circulation during CBM drilling. Depending upon fuzzy balls and colloids in fuzzy balls, the fuzzy ball drilling fluids changed their shapes and properties to completely plug underground heterogeneous seepage channels so as to strengthen the pressure bearing capacity of formations. This paper describes the available features of the fuzzy ball drilling fluid including efficient plugging, good carrying and suspension, formation damage control, compatible weighted by any weighted materials without auxiliary equipment. The fuzzy ball drilling fluids can finish drilling in low pressure natural gas zone, control CBM leakage; control the natural fractures, drilling in different pressures in the same open hole, combination with the air drilling mode, etc. during Ordos CBM drilling. The fuzzy ball drilling fluid will not affect down-hole motors and MWD. The fuzzy ball drilling fluid will be blend simply as conventional water based drilling fluids. The existing CBM drilling equipment can completely meet the fuzzy ball drilling mixing and it is maintained conveniently. The fuzzy ball drilling fluid is the efficient drilling fluid.

Fluorescent Structural DNA Nanoballs Functionalized with Phosphate-Linked Nucleotide Triphosphates

Highly labeled DNA nanoballs functionalized with phosphate-linked nucleotide triphosphates (dNTPs) were developed as a source of dNTPs for DNA polymerase. The particles were prepared by strand-displacement polymerization from a self-complementary circular template. Imaged by atomic force microscopy, these functionalized particles appear as condensed fuzzy balls with diameters between 50 and 150 nm. They emit a bright fluorescent signal, detected in 2 ms exposures with a signal-to-noise ratio of 25 when imaged using a TIR fluorescence microscope.

Aspects on the reverse fuzzy distance transform

We extend the concept of the reverse distance transform for binary images to a fuzzy framework, leading to the reverse fuzzy distance transform. Furthermore, we introduce centres of maximal fuzzy balls intended for, e.g. fuzzy distance based skeletonization of a fuzzy object. Finally, we propose to use the reverse fuzzy distance transform as an alternative region growing process to the seeded watershed segmentation, in order to further emphasize the shape of fuzzy objects. We make a comparison using an application where the aim is to identify the cytoplasms in fluorescence microscopy images of cells.

On fuzzy pseudo-normed vector spaces

We provide a method for introducing fuzzy pseudo-metric topologies on sets, and fuzzy pseudo-normed topologies on vector spaces over R or C which will be fuzzy linear topologies. We define fuzzy pseudo-metrics for pairs of crisp points, and fuzzy pseudo-norms for crisp points, as fuzzy real numbers ⩾ 0 (as defined by Hutton). We define the associated fuzzy open balls, with crisp points for their centres and fuzzy real numbers > 0 for their radii. These form a basis for the associated fuzzy pseudo-metric topology. The axioms governing fuzzy pseudo-metric and fuzzy pseudo-norm are straightforward extensions for the corresponding axioms in the crisp case. The formulation conforms with Zadeh's Extension Principle. We show that Katsaras' concept of fuzzy seminorm (Fuzzy Sets and Systems 12 (1984) 143–154) is equivalent to ours, in the sense that both concepts will result in same fuzzy linear topologies.