Contact Vector Research Articles

On thermodynamic processes, state equations and critical phenomena for homogeneous mixtures

In this paper, we study the thermodynamics of homogeneous mixtures in equilibrium. From the perspective of thermodynamics, substances are understood as Legendre submanifolds, which are equipped with a Riemannian structure in addition. We refer to these as Legendre-Riemannian manifolds. This Legendre structure reflects the law of conservation of energy, while the Riemannian structure corresponds to the second central moment of measurement of extensive quantities, indicating that we only consider stable states. Thermodynamic processes, such as chemical reactions, correspond to contact vector fields that preserve the law of energy conservation, or are contact. The presence of a Riemannian structure distinguishes between three classes of processes: positive, which increase the metric; neutral, which preserve the metric; and negative, which decrease the metric. We provide a detailed description of the processes and suggest a method for finding state equations for a homogeneous mixture in mechanical or chemical equilibrium.

On the second $\mathfrak {osp}(1|2)$-relative cohomology of the Lie superalgebra of contact vector fields on $\mathcal{C}^{1|1}$

On the second $\mathfrak {osp}(1|2)$-relative cohomology of the Lie superalgebra of contact vector fields on $\mathcal{C}^{1|1}$

Stiffness Anisotropy and Micro-Mechanism of Calcareous Sand with Different Particle Breakage Ratios Subjected to Shearing Based on DEM Simulations

Stress-induced anisotropy in calcareous sand can cause an uneven displacement in island reef engineering. In this study, stiffness, as a quantitative indicator, is explored to reveal the stress-induced anisotropy in calcareous sand. Based on the discrete element method, the stiffness anisotropic characteristics of calcareous sand during shearing, as well as the impact of particle breakage, are investigated by numerical simulations. Both the macro and micro responses, i.e., the maximum shear modulus, contact normal, strong and weak contact normal force, and the direction of particle breakage, are explored for calcareous sand with different particle breakage ratios. The results show that calcareous sand exhibits notable anisotropy during shearing, with the maximum shear modulus in the vertical direction (deviatoric stress direction) being significantly greater than that in the horizontal direction. Moreover, the higher the particle breakage rate, the lower the stiffness and its anisotropy. The micro-mechanism results indicate that the primary particle breakage during the shearing process occurs in the vertical direction. That is, the particle breakage weakens the strong contact force in the vertical direction, leading to a redistribution of the strong contact forces from the vertical direction to other directions. This redistribution mainly manifests in a decrease in the anisotropy of contact normal and contact vector within the sample, as well as a decrease in the proportion of strong contact forces in the overall contacts. This, in turn, reduces the shear strength and stiffness of calcareous sand, particularly in the vertical direction, and results in a decrease in the maximum shear modulus and its anisotropy. The maximum reduction can be up to 50% of the original value. These insights can provide a certain theoretical support for the uneven displacement and long-term stability of calcareous sand for islands and reefs.

Equilibria and bifurcations in contact dynamics

We provide a systematic study of equilibria of contact vector fields and the bifurcations that occur generically in 1-parameter families, and express the conclusions in terms of the Hamiltonian functions that generate the vector fields. Equilibria occur at points where the zero-level set of the Hamiltonian function is either singular or is tangent to the contact structure. The eigenvalues at an equilibrium have an interesting structure: there is always one particular real eigenvalue of any equilibrium, related to the contact structure, that we call the principal coefficient, while the other eigenvalues arise in quadruplets, similar to the symplectic case except they are translated by a real number equal to half the principal coefficient. There are two types of codimension 1 equilibria, named Type I, arising where the zero-set of the Hamiltonian is singular, and Type II where it is not, but there is a degeneracy related again to the principal coefficient and the contact of the zero-level set of the Hamiltonian with the contact structure. Both give rise generically to saddle-node bifurcations. Some special features include: (i) for Type II singularities, Hopf bifurcations cannot occur in dimension 3, but they may in dimension 5 or more; (ii) for Type I singularities, a fold-Hopf bifurcation can occur with codimension 1 in any dimension, and (iii) again for Type I, and in dimension at least 5, a fold-multi-Hopf bifurcation (where several pairs of eigenvalues pass through the imaginary axis simultaneously together with one through the origin) may also occur with codimension 1.

Analysis of the Influence of Environmental Health Interventions Based on The Health Belief Model (HBM) on the Risk Factors of Dengue Hemorrhagic Fever (DHF) Benteng Village, Indonesia

Background: Palopo city is one of the endemic areas of DHF, which during the last 5 years DHF morbidity rate has fluctuated. One solution could be environmental health interventions, which aim to enhance disease prevention behavior through positive views based on powerful health messaging. Assessment of entomological indices (Container Index, Breteau Index, and House Index) which is one of risk factors for DHF incidents to see level of density of Aedes sp. larvae can help determine focus of vector control. This study wants to see whether there is an effect of environmental health interventions based on Health Belief Model (HBM) theory on risk factors for DHF. Methods: This research is an experimental study with a Quasy experimental design using One Group Pre-Post test design. The sampling technique is total sampling so that entire population is a sample of 71 houses. Data were analyzed using Mc Nemar test. Results: Result indicated that perceived susceptibility (p value = 0.021), perceived severity (p value = 0.000), perceived benefits (p value = 0.001), perceived barriers (p value = 0.000) and behavior to prevent contact vector (p value = 0.015) were all influenced by environmental health intervention, the entomological index Container Index (CI) was in the low group of moderate, whereas Breteau Index (BI) and House Index (HI) were in the high category of moderate. This indicates that HBM-based environmental health interventions can lower the density of larvae. Conclusion: Environmental health interventions based on HBM can be recommended as an effort to reduce the risk factors for DHF.

On the rigidity of the Sasakian structure and characterization of cosymplectic manifolds

We introduce new metric structures on a smooth manifold (called “weak” structures) that generalize the almost contact, Sasakian, cosymplectic, etc. metric structures (φ,ξ,η,g) and allow us to take a fresh look at the classical theory and find new applications. This assertion is illustrated by generalizing several well-known results. It is proved that any Sasakian structure is rigid, i.e., our weak Sasakian structure is homothetically equivalent to a Sasakian structure. It is shown that a weak almost contact structure with parallel tensor φ is a weak cosymplectic structure and an example of such a structure on the product of manifolds is given. Conditions are found under which a vector field is a weak contact vector field.

On torsion in linearized Legendrian contact homology

In this short note, we discuss certain examples of Legendrian submanifolds, whose linearized Legendrian contact (co)homology groups over integers have non-vanishing algebraic torsion. More precisely, for a given arbitrary finitely generated abelian group [Formula: see text] and a positive integer [Formula: see text], [Formula: see text], we construct examples of Legendrian submanifolds of the standard contact vector space [Formula: see text], whose [Formula: see text]th linearized Legendrian contact (co)homology over [Formula: see text] computed with respect to a certain augmentation is isomorphic to [Formula: see text].

The second cohomology spaces of 𝒦(1) with coefficients in the superspace of weighted densities and deformations of the superspace of symbols on S 1|1

Abstract We explicitly describe the second cohomology of the Lie superalgebra 𝒦 ⁢ ( 1 ) {\mathcal{K}(1)} of contact vector fields on the supercircle S 1 | 1 {S^{1|1}} with coefficients in the spaces of weighted densities. We deduce the second cohomology of 𝒦 ⁢ ( 1 ) {\mathcal{K}(1)} with coefficients in the Poisson algebra of pseudodifferential symbols on S 1 | 1 {S^{1|1}} . We study formal deformations of the standard embedding of 𝒦 ⁢ ( 1 ) {\mathcal{K}(1)} into the Poisson superalgebra of pseudodifferential symbols.

Particle shape effect on the structural evolution and force propagation inside the three-dimensional sandpile.

This paper employs the discrete element method to examine the impact of particle shape on the pressure dip phenomenon and structural characterization of the three-dimensional sandpiles. Particular attention has been given to the underlying mechanism in the sandpile, which arises from the interplay of the initial created structure and the induced changes in the subsequent deposition process. Different aspect ratios produced different initial local geometry. The contact vector and strong contact force rotated away from the z-axis when the aspect ratio deviates from 1.0. The flat particles had a better memory of initial structures under the subsequent deposition process, which plays a vital role in force transmission and stress propagation. However, when the aspect ratio approaches 1.0, the stress state behaves as a joint result of maintained and gained contacts. For a certain range of aspect ratios, the newly generated interactions of elongated particles induced the major stress in the horizontal plane, which thus produces a significant pressure dip phenomenon. The results indicated that complex models accounting for contact creation are required to capture the pressure profile.

Effect of contact vector direction on achieving cavotricuspid isthmus block

Cavotricuspid isthmus (CTI) ablation is an important treatment strategy for CTI-dependent atrial flutter (AFL). The location of the catheter contact area is confirmed by the contact vector direction (CVD) through three-dimensional mapping during the procedure. However, the relationship between CVD during radiofrequency ablation and its efficacy in achieving CTI block has not been clarified. This study aimed to investigate the relationship between CVD and efficacy in achieving CTI block. CVDs during radiofrequency ablation were divided into proximal vectors against the distal tip (P-vector) and other vectors (normal-vector). In 39 patients who underwent CTI linear ablation, the CTIs were divided into two segments: the tricuspid valve area (anterior) and inferior vena cava area (posterior). The frequency of the residual conduction gap was compared between segments in which the P- and normal-vectors were observed. P-vectors were observed in 13 of the 78 segments. The median ablation index was not significantly different between segments in which the P-vector and normal-vector were observed (398.2 [384.2–402.2] vs. 393.3 [378.3–400.1], p = 0.15). However, residual conduction gaps were significantly more frequently observed in the segment in which the P-vector was observed than those in which only the normal-vector was observed (6/13, 46.2% vs. 3/65, 4.6%; p < 0.01). During a 6-month follow-up, two patients required a second session of ablation due to AFL recurrence. A residual conduction gap was observed in one patient at the site where the P-vector was observed in the first session. Avoiding the P-vector might be an important factor in improving CTI block and reducing AFL recurrence.

Mathematical Modeling and Dynamic Analysis of a Spherical Contact Vector Thruster

Mathematical Modeling and Dynamic Analysis of a Spherical Contact Vector Thruster

On [formula omitted]-relative cohomology on [formula omitted

Over the (1,2)-dimensional real superspace R1|2. We compute the second aff(2|1)-relative cohomology space of K(2) with coefficients in the module of λ-densities Fλ2 on R1|2, where K(2) is the Lie superalgebra of contact vector fields on R1|2 and aff(2|1) is the affine Lie superalgebra. We give explicitly 2-cocycles spanning these cohomology spaces. This result is based specially on the classification of aff(2|1)-invariant bilinear differential operators acting on the superspaces of weighted densities given in [2].

A study of conformal almost Ricci solitons on Kenmotsu manifolds

The goal of this paper is to study conformal almost Ricci solitons within the framework of Kenmotsu manifolds. First, we demonstrate that if the potential vector field is Jacobi along the Reeb vector field, then the soliton reduces to a conformal Ricci soliton. If the manifold is [Formula: see text]-Einstein Kenmotsu manifold, we show that either the manifold is of constant scalar curvature or the potential vector field is an infinitesimal contact transformation. In addition, if we consider the soliton vector field as a contact vector field, then either the gradient of [Formula: see text] is pointwise collinear with the Reeb vector field or the manifold becomes [Formula: see text]-Einstein. Lastly, we develop an example of a conformal almost Ricci soliton on the Kenmotsu manifold.

The possibility of X(4014) as a D^*{bar{D}}^* molecular state

Within the framework of the local hidden gauge approach, we have studied the near-threshold D^* {bar{D}}^* interaction with quantum numbers I(J^{PC}) = 0(0^{++}), 0(2^{++}), 1(0^{++}), and 1(2^{++}), respectively. The contact term and vector meson exchange term in coupled channels are taken into account in this work. One pole, which is found in the case of the quantum numbers I(J^{PC}) = 0(0^{++}), could be associated to the X(4014) recently observed by the Belle Collaboration. Thus, we suggest that the X(4014) may be an D^* {bar{D}}^* molecular state with I(J^{PC}) = 0(0^{++}), and more precise information about X(4014), such as resonance parameters and decay properties, could be useful to shed light on its structure.

Electromyography measurements of the deep hip muscles do not improve estimates of hip contact force

The deep hip muscles are often omitted in studies investigating hip contact forces using neuromusculoskeletal modelling methods. However, recent evidence indicates the deep hip muscles have potential to change the direction of hip contact force and could have relevance for hip contact loading estimates. Further, it is not known whether deep hip muscle excitation patterns can be accurately estimated using neuromusculoskeletal modelling or require measurement (through invasive and time-consuming methods) to inform models used to estimate hip contact forces. We calculated hip contact forces during walking, squatting, and squat-jumping for 17 participants using electromyography (EMG)-informed neuromusculoskeletal modelling with (informed) and without (synthesized) intramuscular EMG for the deep hip muscles (piriformis, obturator internus, quadratus femoris). Hip contact force magnitude and direction, calculated as the angle between hip contact force and vector from femoral head to acetabular center, were compared between configurations using a paired t-test deployed through statistical parametric mapping (P < 0.05). Additionally, root mean square error, correlation coefficients (R2), and timing accuracy between measured and modelled deep hip muscle excitation patterns were computed. No significant between-configuration differences in hip contact force magnitude or direction were found for any task. However, the synthesized method poorly predicted (R2-range 0.02–0.3) deep hip muscle excitation patterns for all tasks. Consequently, intramuscular EMG of the deep hip muscles may be unnecessary when estimating hip contact force magnitude or direction using EMG-informed neuromusculoskeletal modelling, though is likely essential for investigations of deep hip muscle function.

Second cohomology of the Lie superalgebra of contact vector fields on weighted densities on the superspace [formula omitted

We consider the superespace K1|n endowed with its standard contact structure defined by the 1-form αn. We compute the second differential cohomology of the Lie superalgebra K(n) of contact vector fields with coefficients in the superspace of weighted densities on the (1,n)-dimensional superspace, n>2. Following Feigin and Fuchs, we explicitly give 2-cocycles spanning this cohomology space. This work is the simplest generalization of a result by O. Basdouri et al. (2020) [6].

A review on microbiological safety of Ready-To-Eat Salads

Eating of road side ready-to-eat (RTE) salads that is made with green leafy vegetables (GLVs) commonly lettuce (Lactuca sativa L.), cabbage (Brassica oleracea var. capitata) or Cress (Lepidium sativum Linn.) as the key constituents coupled with adding tomatoes, sliced onions, cucumber, groundnut cake and so on has been reported to cause severe safety threats owing to its being extremely disposed to microbiologically inclined contamination, thereby leading to a public health issue. Pathogenic microorganisms pollute salads as a result of mishandling of raw vegetables, during preparation of salads and also associated environment. Soils typically harbor abundant microorganisms, some of which are human pathogens such as B. cereus, Clostridium botulinum, C. perfringens, Listeria monocytogenes and Aeromonas. Birds are carriers of pathogens such as E. coli O157:H7, Salmonella and Campylobacter. Reptiles and arthropods are usually in cultivation fields, and therefore have unrestricted access to produce and many bacterial species have evolved to exploit these animals as hosts or vectors. Insect deterioration creates openings that aid the ingress of pathogens into inner plant tissues, thereby enhancing colonization of spoilage and pathogenic bacteria on produce. Not only animals, similarly people working with the vegetables produce are known to be a source and direct contact vector of microorganisms. Hence this type of food is regarded as potential vehicles of food borne illnesses resulting in large and serious national and international outbreaks. Thus, the essence of this study is to review the safety of the RTE vegetable salads, assessing the contamination level of the most prevalent pathogenic microorganisms. RTE salads can be contaminated with different types of foodborne pathogens from farm-to-fork that makes them unsafe for human consumption. Regulatory bodies should design periodic workshop training for RTE food hawkers to help fix the problems and enhance the effectiveness of RTE vegetables salads preparation. Public awareness on the serious health risk associated with mishandled or poorly prepared minimally processed RTE foods most especially vegetable salads should be considered.

On topologically distinct infinite families of exact Lagrangian fillings

In this note we construct examples of closed connected Legendrian submanifolds in high dimensional contact vector space that admit an arbitrary finite number of topologically distinct infinite families of diffeomorphic, but not Hamiltonian isotopic exact Lagrangian fillings.

Lifting the non-isothermal CSTR dynamics to the complete Thermodynamic Phase Space

This paper deals with the contact formulation of the contact geometry of irreversible thermodynamics. Firstly, a family of parameterized contact Hamiltonian functions, defined on the complete Thermodynamic Phase Space, generating non-strict contact vector fields which are equivalent on the associated Legendre submanifold, is proposed using both the Gibbs relation and the Gibbs-Duhem relation. Secondly, the parameterized lifts of the CSTR dynamics to the complete Thermodynamic Phase Space are performed, while guaranteeing the global attractivity of the Legendre submanifold on which the dynamics of the system is living.

Some classes of 3-dimensional Trans-Sasakian manifolds with respect to semi-symmetric metric connection

The object of the present paper is to study semi-symmetric metric connection on a 3-dimensional trans-Sasakian manifold. We found the necessary condition under which a vector field on a 3-dimensional trans-Sasakian manifold will be a strict contact vector field. Then, we obtained extended generalized phi-recurrent 3-dimensional trans-Sasakian manifold with respect to semi-symmetric metric connection. Next, a 3-dimensional trans-Sasakian manifold satises the condition ~L.~ S = 0 with respect to semi-symmetric metric connection is studied.