Terms Of Rigidity Research Articles

Running vacuum in quantum field theory in curved spacetime: renormalizing rho _{vac} without sim m^4 terms

The Lambda -term in Einstein’s equations is a fundamental building block of the ‘concordance’ Lambda CDM model of cosmology. Even though the model is not free of fundamental problems, they have not been circumvented by any alternative dark energy proposal either. Here we stick to the Lambda -term, but we contend that it can be a ‘running quantity’ in quantum field theory (QFT) in curved space time. A plethora of phenomenological works have shown that this option can be highly competitive with the Lambda CDM with a rigid cosmological term. The, so-called, ‘running vacuum models’ (RVM’s) are characterized by the vacuum energy density, rho _{vac}, being a series of (even) powers of the Hubble parameter and its time derivatives. Such theoretical form has been motivated by general renormalization group arguments, which look plausible. Here we dwell further upon the origin of the RVM structure within QFT in FLRW spacetime. We compute the renormalized energy-momentum tensor with the help of the adiabatic regularization procedure and find that it leads essentially to the RVM form. This means that rho _{vac}(H) evolves as a constant term plus dynamical components {{mathcal {O}}}(H^2) and mathcal{O}(H^4), the latter being relevant for the early universe only. However, the renormalized rho _{vac}(H) does not carry dangerous terms proportional to the quartic power of the masses (sim m^4) of the fields, these terms being a well-known source of exceedingly large contributions. At present, rho _{vac}(H) is dominated by the additive constant term accompanied by a mild dynamical component sim nu H^2 (|nu |ll 1), which mimics quintessence.

3D-Printed PEEK Extravascular Stent in the Treatment of Nutcracker Syndrome: Imaging Evaluation and Short-Term Clinical Outcome

Minimally invasive options are safe and reliable alternatives for the treatment of nutcracker syndrome (NCS). After continued efforts, our team successfully devised a new and effective therapeutic method: 3D-printed extravascular stenting of the left renal vein. From December 2017 to May 2019, 28 patients (25 men and 3 women) from different parts of China between 18 and 37 years old (mean, 23.6 years) diagnosed with NCS were admitted for laparoscopic 3D-printed extravascular stenting treatment. The post-operative follow-up duration was 6–24 months (median, 16.3 months). Technical success of the operation was achieved in all patients. After treatment, the NCS symptoms all patients resolved or improved during the follow-up period, without relapse. Most symptoms, including macro-/microhematuria, proteinuria, and flank/abdominal pain, tended to resolve within 3–6 months after the surgery; other symptoms, such as left-sided varicocele, also showed varying degrees of improvement at different times post-operatively. Perioperative complications were noted in two patients, including transient and mild lymphatic leakage, without any adverse effects. All extravascular stents were visualized on computed tomography and Doppler ultrasound scans, and no migration or any side effects occurred during the entire follow-up period. Compared to endovascular stenting or polytetrafluoroethylene artificial vessel procedures, 3D-printed polyetheretherketone extravascular stenting has more advantages in terms of stent design and rigidity and approach rationality while successfully preventing stent migration and thrombosis. Therefore, this method may serve as an accurate and effective treatment for NCS patients.

On Uniquely Registrable Networks

Consider a network with $N$ nodes in $d$ -dimensional Euclidean space, and $M$ subsets of these nodes $P_1,\ldots, P_M$ . Assume that the nodes in a given $P_i$ are observed in a local coordinate system. The registration problem is to compute the coordinates of the $N$ nodes in a global coordinate system, given the information about $P_1,\ldots, P_M$ and the corresponding local coordinates. The network is said to be uniquely registrable if the global coordinates can be computed uniquely (modulo Euclidean transforms). We formulate a necessary and sufficient condition for a network to be uniquely registrable in terms of rigidity of the body graph of the network. A particularly simple characterization of unique registrability is obtained for planar networks. Furthermore, we show that $k$ -vertex-connectivity of the body graph is equivalent to quasi $k$ -connectivity of the bipartite correspondence graph of the network. Along with results from rigidity theory, this helps us resolve a recent conjecture due to Sanyal et al. (R. Sanyal, M. Jaiswal, and K. N. Chaudhury, “On a registration-based approach to sensor network localization,” IEEE Trans. Signal Process. , vol. 65, no. 20, pp. 5357–5367, Oct. 2017.) that quasi three-connectivity of the correspondence graph is both necessary and sufficient for unique registrability in two dimensions. We present counterexamples demonstrating that while quasi $(d+1)$ -connectivity is necessary for unique registrability in any dimension, it fails to be sufficient in three and higher dimensions.

Starch nanocrystals as the particle emulsifier to stabilize caprylic/capric triglycerides-in-water emulsions

Starch nanocrystals (SNCs) grafted with octenyl succinic anhydride (OSA) were used to stabilize caprylic/capric triglycerides (GTCC)-in-water emulsions. The morphology and viscoelasticity of emulsions were studied in terms of particle loadings and degrees of substitution (DSs). It is found that the emulsifying capacities of SNCs increase with increased DSs. Both the pristine SNC and modified ones can be well used to stabilize emulsions, whereas the emulsification follows different mechanisms. The platelet-like structure of SNCs, together with its improved amphiphilicity after surface treatments, are important to the formation and evolution of droplet clusters. The deformation and relaxation of those clusters result in weak flow overshoots and strong thixotropy in different shear flow fields, which favor storage and applications of GTCC-in-water emulsions as hydrocolloids. The mechanisms were then discussed in terms of rigidity of SNC and relaxations of clusters. This work proposes a promising application of SNC in food and cosmetic industries.

Evaluation of the experimental curvature ductility of RC beams externally strengthened with CFRP bands

This paper presents an experimental research about bending response of a set of reinforced concrete beams strengthened with external CFRP (RCB-SCFRPs). The aim of the research was to make an evaluation of curvature ductility using experimental data and to generate simplified expressions to estimate the ductility of RCB-SCFRP. In addition, the experimental behavior and the resulting failure modes on bending are also studied by experimental tests. Seventeen natural-scale RCB-SCFRPs with different configurations of reinforced steel bars and FRP (Fiber-reinforced polymer) bands from three manufacturers are designed and loaded under monotonic four points bending tests. In fact, three groups of RCB-SCFRPs were designed in order to evaluate the effect of FRP longitudinal ratio and the external transverse FRP reinforcement (Groups I and II) and to obtain the failure bending modes described in ACI 440.2R [1] (Group III).Flexural capacity and curvature ductility are some of the most important and well-known parameters for analysis and design of traditional RC beams. The calculation of these same parameters in the application of RCB-SCCFRP is not straightforward to compute. Because of this difficulty, the present research focuses on the study of bending behavior and evaluating ductility in terms of FRP axial rigidity, and the steel and CFRP reinforcement ratio.For this purpose, the experimental bending moment-curvature (M-Ф) diagrams were constructed using a proposed approach based on geometric compatibility. The effect of the transverse FRP reinforcement such as U-clamps is not completely clear, but in most cases, the RCB-SCFRPs with transverse reinforcement showed the best performance in final curvature and a greater ductility. Test results indicate that the RCB-SCFRP bending behavior was critically influenced by the FRP properties. Additionally, the FRP axial rigidity had a critically adverse effect on the curvature ductility of the RCB-SCFRPs tested.Furthermore, several expressions based on internal forces equilibrium for predicting the failure bending mode and curvature ductility of RCB-SCFRPs are proposed, which are consistent with experimental data.Finally, a simplified method is proposed to obtain a well-estimated value of curvature ductility considering FRP axial rigidity and steel reinforcement ratio, which could be very helpful to the researcher and designer engineer.

Structure, activity and dynamics of extra virgin olive oil-in-water nanoemulsions loaded with vitamin D3 and calcium citrate

Extra virgin olive oil-in-water (O/W) nanoemulsions loaded with vitamin D3 and calcium citrate were developed and studied in terms of structure, activity and dynamics. The nanoemulsions were formulated with a two-step emulsification procedure using water as the continuous phase, extra virgin olive oil (EVOO) as the dispersed phase and mixtures of food grade surfactants as stabilizers. The nanoemulsions were investigated for their particle size, polydispersity and stability over time by Dynamic light scattering (DLS) analysis. Among the different nanoemulsions studied, those based on polysorbate 20 in combination with lecithin produced systems owing EVOO droplets of 285 ± 5 nm diameter and 0.202 ± 0.01 PdI that were stable for 37 days. These stable nanoemulsions were loaded with calcium citrate and vitamin D3 to result formulations containing both water and oil soluble micronutrients. The presence of calcium ions in the aqueous phase strongly affected the stability of the nanoemulsions whereas vitamin D3 addition in the dispersed oil phase affected the size of the oil cores by several nanometers. Interfacial properties were investigated using Electron Paramagnetic Resonance (EPR) spectroscopy employing an amphiphilic spin probe. The nature of the surfactant and the presence of vitamin D3 and calcium citrate affected the properties of the surfactants' layer in terms of rigidity, local viscosity and polarity. More specifically, upon encapsulation vitamin D3 resulted in more ordered and viscous interfaces. Antioxidant potential of the proposed nanocarriers was investigated with an EPR procedure based on the scavenging the 4-hydroxy-TEMPOL. EPR signal inhibition was observed due to the scavenging activity of hydrogen donating moieties present both in empty and loaded nanoemulsions. Diffusion ordered NMR spectroscopy (DOSY NMR) successfully revealed the solubilization of the lipophilic vitamin D3 in the dispersed oil phase of the nanoemulsion formulation.

Synthesis of partially bio‐based triepoxides from naturally occurring myo‐inositol and their polyadditions

AbstractPartially bio‐based triepoxides, 1,3,5‐tri‐O‐methyl‐2,4,6‐tri‐O‐(oxiran‐2‐yl‐methyl)‐myo‐inositol (4) and 2,4,6‐tri‐O‐(oxiran‐2‐yl‐methyl)‐myo‐inositol 1,3,5‐orthoacetate (5), were synthesized from naturally occurring myo‐inositol. These two triepoxides differ from each other in terms of rigidity of the core structure; while the former triepoxide has a more flexible cyclohexane core, the latter has a highly rigid adamantane‐like orthoester core. Triepoxide 5 readily reacted with nucleophilic monomers such as diamines, dithiol, and trithiol to yield networked polymers. The glass transition temperatures (Tgs) of these polymers were higher than those of comparable networked polymers obtained by the polyaddition of triepoxide 4 with the same nucleophilic monomers, implying that the rigidity of the orthoester moiety contributed to the efficient restriction of the polymer chain in the synthesized networked polymers.

Coquasi-Bialgebras with Preantipode and Rigid Monoidal Categories

By a theorem of Majid, every monoidal category with a neutral quasi-monoidal functor to finitely-generated and projective $\Bbbk$-modules gives rise to a coquasi-bialgebra. We prove that if the category is also rigid, then the associated coquasi-bialgebra admits a preantipode, providing in this way an analogue for coquasi-bialgebras of Ulbrich's reconstruction theorem for Hopf algebras. When $\Bbbk$ is field, this allows us to characterize coquasi-Hopf algebras as well in terms of rigidity of finite-dimensional corepresentations.

KEEFEKTIFAN KALIMAT DALAM TEKS EKSPLANASI SISWA KELAS VIII SMP PEMBANGUNAN LABORATORIUM UNP

ABSTRACT The purpose of this study is to describe the sentences in the explanatory text of students in terms of four things. First, the effectiveness of sentences in terms of structural clarity, there are 78 (19.60%) errors. The ineffectiveness of the sentence is in the active / passive structure (1 error), the subject is not an explanation (21 errors), the predicate is not lost (28 errors), the description is not in the form of a subject (4 errors), and the subject is not lost (25 errors). Second, the effectiveness of sentences in terms of logical meaning there are 76 (19.09%) errors. The ineffectiveness of the sentence lies in the logical relationship S and P (52 errors) and the logical relationship of details or parallel meaning (23 errors). Third, the effectiveness of sentences in terms of word saving is 142 (35.68%) errors. The ineffectiveness of the sentence is on one subject from the same subject (46 errors), one word from several synonymous words (21 errors), and the required word (115 errors). Fourth, the effectiveness of sentences in terms of word rigidity there are 102 (25.63%) errors. Based on these results it can be concluded that the sentences in the explanatory text of eighth grade students of SMP Pembangunan Laboratorium Laboratory are not effective. This is evidenced from the 221 sentences studied, there were 31 (14.03%) effective sentences and 190 (85.97%) ineffective sentences with 398 errors. Kata kunci: Keefektifan Kalimat, Teks Eksplanasi

Multi-objective topology optimization and structural analysis of periodic spaceframe structures

Reduction of structural weight provides significant benefits in many engineering applications. While methods to optimise structural shape and topology of both continuous solids and discrete frame structures have existed for a while, the advent of additive layer manufacturing processes has enabled more complex geometries to be feasible. In this paper, a periodic spaceframe structure is designed for minimum mass and maximum effective flexural and torsional rigidities. A method of parametrising the spaceframe through its constituent unit cells is proposed, and Genetic Algorithm (GA) multi-objective optimisation is used to optimise its topology, size and geometry as a generic structure. The superior performance of the topology optimised periodic spaceframe is highlighted in terms of structural rigidity, large deformation capability, buckling and vibrational modal analysis in compare to equivalent beam structures of identical weight and comparable domain. The results show that the proposed method can effectively generate lightweight substitute structures of great mechanical performance in many beam structures applications, such as: aircraft wing spars. The periodic spaceframe is applied into a conventional aircraft wing structure to demonstrate the possibilities of promoting weight saving in the design of civil aircraft wings.

Effectiveness of Deep Brain Stimulation in Parkinsonism

Introduction: Deep brain stimulation (DBS) is a neurosurgical procedure indicated for patients with advanced Parkinson’s disease (PD).This study aimed to investigate the relative efficacy and safety of DBS when medical therapy is ineffective in advanced PD. Material and Method: 50 patients whom were on medical treatment for long and started to have side effects of the drugs were the part of the study to find the improvement in the status in terms of tremors, dyskinesia and rigidity. Results: Preoperatively and postoperatively comparison in the improvement was done which revealed, improvement was 75%, 61.5% and 58 % respectively in tremors, rigidity and dyskinesia. There was statically significantly improvement rigidity, tremor and the dyskinesia, the patients needed smaller doses of the medications and showed less signs of distress. Conclusion: Our results clearly suggested that with Deep Brain Stimulation patients showed significant improvement with decreased dose of medication.

Effectiveness of Deep Brain Stimulation in Parkinsonism

Introduction: Deep brain stimulation (DBS) is a neurosurgical procedure indicated for patients with advanced Parkinson’s disease (PD).This study aimed to investigate the relative efficacy and safety of DBS when medical therapy is ineffective in advanced PD. Material and Method: 50 patients whom were on medical treatment for long and started to have side effects of the drugs were the part of the study to find the improvement in the status in terms of tremors, dyskinesia and rigidity. Results: Preoperatively and postoperatively comparison in the improvement was done which revealed, improvement was 75%, 61.5% and 58% respectively in tremors, rigidity and dyskinesia. There was statically significantly improvement rigidity, tremor and the dyskinesia, the patients needed smaller doses of the medications and showed less signs of distress. Conclusion: Our results clearly suggested that with Deep Brain Stimulation patients showed significant improvement with decreased dose of medication.

‘Beat Your Plowshares into Swords and Your Pruninghooks into Spears’: A Contextual Critique of Expulsion Decisions and Appeal Rights in the United Kingdom

The putative question is whether the United Kingdom complies with its treaty obligations under International Human Rights Law (IHRL) in the expulsion of migrants? The debate is that expulsion laws as they stand may have been contrived to enhance deportability or removability. It is further argued that the ever increasing and shifting pattern of deportation laws (some of which are retroactive) appears to violate the basic principles of human rights norms. This is heightened by the fact that these laws are either discretionary or couched in rigid terms leaving less chance for compassionate considerations even in the light of unclear judicial interpretation given to some of these expulsion laws. Although, States are afforded some discretion as to the manner in which they conform to their obligations under IHRL, that discretion, however, must not result in the practical denial of the minimum procedural safeguards needed to protect the migrant against arbitrary expulsion. By certifying decisions regarding expulsion, the paper finds that the State ab initio creates the amphitheater for expulsion of migrants. The argument is that the dichotomy between an ‘immigration decision’ and ‘non-immigration decision’ is a false one as it is probably anchored with the apparent intention of achieving expulsion of migrants from the UK in an ostensibly hostile environment. It is curious that the irregular migrant who makes an application (usually by payment of a fee) to the Home Office to regularize his stay which was eventually refused will not be accorded a right of appeal simply because, the State sees such applications as not befitting of a right of appeal. It is therefore difficult to justify the rationale to deny a right of appeal to a migrant or to dichotomize between an immigration decision and a non-immigration decision in the light of the immigration rules. The doctrinal methodology is applied in this paper.

The Global Attractors and Dimensions Estimation for the Higher-Order Nonlinear Kirchhoff-Type Equation with Strong Damping

The initial boundary value problems for a class of high order Kirchhoff type equations with nonlinear strongly damped terms are considered. We establish the existence and uniqueness of the global solution of the problem by using prior estimates and Galerkin’s method under proper assumptions for the rigid term. Then the compact method is used to prove the existence of a compact family of global attractors in the solution semigroup generated by the problem. Finally, the Frechet differentiability of the operator semigroup and the decay of the volume element of linearization problem are proved, and the Hausdorff dimension and Fractal dimension of the family of global attractors are obtained.

Adhesive Joint Stiffness in the Aspect of FEM Modelling.

The paper presents the results of nanoindentation testing, carried out along the thickness of the adhesive joint joining sheets of aluminum alloy. The purpose of the tests was to determine changes in the Young’s modulus in the joint resulting from the active impact of the joined aluminum alloy sheets on the adhesive during curing of the adhesive bond. Structural changes that take place during curing of the joint, especially in the boundary zone, can have a significant impact on the adhesive properties and consequently, on the adhesive joint strength. The Young’s modulus of the adhesive (Ek) in the joint assumes variable values as the distance from the connections changes. This phenomenon is called the apparent Young’s modulus. The problem is to define the size of the boundary zone in which the value of Ek significantly differs from the value in the so-called core. Based on the obtained results of experimental tests, a numerical model was built taking into account the observed differences in the properties of the joint material. The stress distribution in the adhesive joint, single-lap connection with the three-zone adhesive joint, was analyzed in comparison to the classical numerical model in which adhesive in the adhesive joint is treated as isotropic in terms of rigidity.

Experimental Studies on the Performance of Prestressed Concrete Slabs with Parabolic Tendon Profile Shapes

Slab without beams cause bending cracks in the tensile region at a low loading level. One way to overcome these weaknesses is to provide a pre-concentric or eccentric initial bias style. In this study, we wanted to compare the performance of prestressed concrete slabs in terms of cross-sectional strength capacity and rigidity of concrete slab without prestressing through experiments. Objects that were tested without prestressing were made 1 piece, namely P1, and objects that were tested with prestressing were 3 piecesnamely P2 with 2 tendons, P3 with 3 tendons, and P4 with 4 tendons. The dimensions of each object tested are 100 × 40 × 8 cm and all of them are designed with concrete qualityf'c = 30 Mpa. The tendon usedis 8 mm plains teel that is pulled by tightening the nuts at both ends, with a parabolic profile shape and eccentricity value in the middle span of 1.5 cm. From the test results obtained a very significant increase in the crosssectional strength capacity of specimens P2, P3 and P4 against P1. The increase in peak load that can be borne by 192.18% is for P2, 286.54% is for P3, and 383.00% is for P4. It also happened to increase the peak bending moment which can be borne by 161.57% for P2, 241.05% for P3, and 322.68% for P4. Keywords: Concrete, Moment . DOI : 10.7176/CER/11-10-05 Publication date: November 30 th 2019

Coupled states of dual side-by-side inverted flags in a uniform flow

The dynamics of dual side-by-side inverted flags with free leading edges and clamped trailing edges in a uniform flow are simulated using the immersed boundary method. The dynamics of the two inverted flags are systematically analyzed in terms of the bending rigidity, the gap distance between flags and the six initial conditions which are set by adjusting the initial angle of attack of flags. Four distinct dynamic regimes are observed: straight, flapping, chaotic and deflected regimes. According to the relative bending directions in which the inverted flags are bent, the deflected regime is further divided into three sub-regimes: outside deflected, inside deflected and one-side sub-regimes. It is found that the initial conditions exert an influence on which sub-regime to occur. Bistable state occurs in transition from the straight regime to the flapping regime, from the chaotic regime to the flapping regime, and from the flapping regime to the deflected regime.

Estimation of efficiency of hip joint capsule cut fixation with polypropylene mesh

Relevance. Dislocation of the femoral component of the endoprosthesis is one of the most frequent complications in the total hip joint endoprosthesis (THJE). There are many factors for the development of dislocations. The best option to «treatment» a dislocation in THJE is to prevent the development of primary instability. Of particular relevance to the restoration of the capsule-ligament apparatus is for people with obesity. Careful restoration of soft tissue structures or the preservation of these structures using modified accesses significantly reduces the incidence of dislocations. Currently developed many ways to strengthen and restore the posterior structures of the hip joint capsule. In this paper, we study a method for restoring and strengthening the posterior structures of the hip joint capsule using polypropylene-based mesh implants. Purpose: to evaluate the effectiveness of using a polypropylene mesh to close a defect in the hip joint capsule. Materials and methods. The study was carried out in a software package based on the finite element method. For the rational use of computer resources, a computational model was built, which consisted only of the capsule model and the endoprosthesis head model. The dimensions of the elements of the computational model corresponded to the actual dimensions of these objects. In this paper, two ways of capsule suturing were investigated: interrupted sutures and polypropylene mesh. Also, an additional control model of the same dimensions was constructed, but in which the incision was not sutured. Results and its discussion. As a result of the calculations, pictures of the distribution of the stress-strain state in the «head-capsule» system were obtained. To assess the effectiveness of the method of closing the capsule, as the main characteristics, the values of the opening of the incision, as well as the stresses arising in the joint capsule, were chosen. An additional characteristic is selected stresses in the head. Conclusions. The obtained calculation results indicate that with the considered options for fixing the cut, both in terms of rigidity and strength, the model of fixing the defect with a mesh is more effective.

Development of a microstructural grand potential-based sintering model

Microstructure is a controlling factor in the behavior of sintered materials. This work presents a quantitative phase field model of thermal sintering that predicts the evolution of the microstructure by capturing the sintering stress, GB/vacancy interactions, non-uniform diffusion, and grain coarsening without introducing a separate rigid body motion term. The model provides a mechanistic description of sintering using the grand potential phase field approach. Small test simulations are used to verify the new model against sintering theory, and they show that 3D simulations predict faster densification and coarsening than 2D simulations. 3D simulations are compared against experimental data available in the literature. The results of this comparison show that the model provides a reasonable estimate of the sintering behavior, though it overpredicts the sintering rate. This may be due to uncertainty in the material parameters and the relatively small scale of the simulation.

Data-driven weight optimization for real-time mesh deformation

3D model deformation has been an active research topic in geometric processing. Due to its efficiency, linear blend skinning (LBS) and its follow-up methods are widely used in practical applications as an efficient method for deforming vector images, geometric models and animated characters. LBS needs to determine the control handles and specify their influence weights, which requires expertise and is time-consuming. Further studies have proposed a method for efficiently calculating bounded biharmonic weights of given control handles which reduces user effort and produces smooth deformation results. The algorithm defines a high-order shape-aware smoothness function which tends to produce smooth deformation results, but fails to generate locally rigid deformations.To address this, we propose a novel data-driven approach to producing improved weights for handles that makes full use of available 3D model data by optimizing an energy consisting of data-driven, rigidity and sparsity terms, while maintaining its advantage of allowing handles of various forms. We further devise an efficient iterative optimization scheme. Through contrast experiments, it clearly shows that linear blend skinning based on our optimized weights better reflects the deformation characteristics of the model, leading to more accurate deformation results, outperforming existing methods. The method also retains real-time performance even with a large number of deformation examples. Our ablation experiments also show that each energy term is essential.