Pole Strength Research Articles

Analysis of failure mechanism of concrete pole based on finite element extended method

Concrete poles play an important role in distribution networks and are prone to degradation due to environmental influences. Fracture failures primarily result from structural deterioration, including both damage to the concrete structure under stress overload conditions and the deterioration of the concrete material itself. Due to the lower tensile strength compared to compressive strength, concrete structures often exhibit cracking and fractures. This study initially analyzes the structural deterioration process of concrete electric poles and subsequently develops a damaged model using the finite element method. The results reveal that the maximum tensile strength of concrete electric poles occurs at 2.4 m, while the compression is maximum within the 2–6 m range. Furthermore, an analysis of the main factors contributing to fracture failures and structural deteriorations of these poles is conducted using the finite element extension method. It is determined that shallower crack depths and higher concrete strength enhance fracture resistance and the bearing capacity of concrete poles. Notably, annular cracks at the 2.4 m height are more prone to spreading.

Influence of the Long-Term Loading on the Strength and Rigidity of the Annular Section Poles

Introduction. The modern methods of analysis and conducting the numerical experiments referring to calculation and design of constructions are mostly aimed at a deeper study of parameter changes of different structures exposed to the influence of the certain loads. Due to the course of time and upon obtaining and analysing the new results of the numerical studies, there arises the need to revise and update the normative documents developed in the past in the frame of studying the certain modes of structures’ operation. Bearing in mind the above-mentioned objective, the numerical study presented in this article has been carried out.Materials and Methods. It should be mentioned, that most of the previously conducted research was based on the results of the short-term exposure of the structures to the loads, but not enough attention was paid to the study of the influence of the long-term loading on the structures' operation. This paper presents the results of the numerical experiments investigating the load-bearing capacity, flexural rigidity and maximum force of the power transmission line poles exposed to the short-term and long-term loads. The specimen under study is the cylindrical power transmission line pole complying with the GOST 22687.2 “Centrifugal cylinder reinforced concrete posts for high-voltage transmission lines”.Results. The paper presents the results of studying the behaviour of the cylindrical reinforced concrete poles, serving as the supports for the electrical power transmission lines, under the short-term and long-term loading. The work provides the results of numerical experiments investigating the strength and rigidity parameters of the above-mentioned structures under different types of loading, as well as upon changing the eccentricities of the application of these loads. The assessment of the rigidity parameters change under the long-term exposure of the poles to the loads is carried out.Discussion and Conclusion. Based on the results, obtained during the numerical experiments, the strength and rigidity parameters of the annular section power transmission line poles were analysed, and proposals for improving the design codes were made that could become a basis for the further research on this issue.

Studies of spun concrete poles for electric power transmission line supports reinforced with Au1000P rebars

Introduction. In connection with the present volumes of electrification in central Russia, the need for the construction of new electric power transmission lines (EPTLs) has decreased considerably. At the same time, the natural degradation of EPTL supports in time, as well as the prospects for developing the vast expanses of the northern, Siberian and Far Eastern regions, caused by the reorientation of Russia’s economic relations from the West to the East, make it urgent to increase production volumes and technical and economic efficiency of using spun reinforced concrete poles for EPTL supports.Aim. Industrial implementation of spun reinforced concrete poles with the high-strength innovation profile reinforcement by replacing A800 rebars with four-row-profile Au1000P rebars.Materials and methods. The article provides data on the full-scale tests of spun reinforced concrete poles for EPTL supports according to the GOST 22687.1-85 “Centrifugal cylinder reinforced concrete posts for high-voltage transmission lines. Structure and dimensions” [1]. Three pole samples with a length of 26 m were prepared and tested. One sample consisted of prestressed A800 rebars according to GOST 22687.1-85, while the other two prototypes include the prestressed Au1000P rebars with the four-row profile. In the second sample, the reinforcement scheme (diameters and rebar quantity) repeats the standard option, increasing the bearing capacity of the pole. Having the same bearing capacity as the pole, manufactured according to the GOST, the third sample promoted for the reduction in the quantity of non-stressed rebars.Results. A new scheme for reinforcing the pole sample using Au1000P rebars was developed. The results of the sample testing are presented; a comparative evaluation of the pole strength and deformation characteristics is given; technical and economic indicators, as well as the recommendations regarding the reinforcement of the prestressed spun concrete poles with Au1000P rebars are provided.Conclusion. According to the results of the performed study, an economic effect was established due to a reduction in the quantity of non-stressed rebars by 28 %. Poles with Au1000P prestressed rebars have an increased corrosion resistance and durability due to the closing of cracks formed during the impact of short-term dynamic loads from wind gusts, wire breaks, etc. In terms of a recommendation, it is proposed to update the GOST 22687.1-85 in order to use new types of high-strength reinforcement rolled products and higher strength concrete.

Tunable Hydrophobic Octadienyl-Ether Nanocelluloses by In Situ Ultrasonication for Reinforced Polymers and Water-Resistant Paper

One-pot syntheses and in situ ultrasonication have been optimized to generate tunable and highly hydrophobic 2,7-octadienyl-ether (ODE) cellulose nanofibrils (CNFs). Using only butadiene sulfone to serve as dual reaction medium and precursor to 1,3-butadiene (1,3-BD) for telomerization with cellulose hydroxyls, the OH-to-ODE conversion significantly improved from ca. 0.7 to 1.2, 1.8, 3.1, and 4.1 mmol of ODE/g-cellulose at 103–110 °C for 1–2 h. Ultrasonication was highly effective and versatile in the direct disintegration of ODE-cellulose (ODE-cell) in nonpolar organic solvents and plant oils into ODE-CNFs as well as pretreating cellulose for improved functionalization. Mixing 2 wt % in situ ultrasonicated 1.2 mmol of ODE/g-cell improved the modulus of polybutadiene six times and the strength of poly(styrene-b-isoprene-b-styrene) three times, whereas in situ ultrasonication of 1.8 mmol/g-cell directly with linseed oil at merely 0.07 wt % created holistic biobased hydrophobic cellulose paper to resist water penetration while also significantly improving the tensile strength. This optimized telomerization and streamlined in situ ultrasonication approach has presented a sustainable synthesis and processing strategy to generate highly hydrocarbon-compatible nanocelluloses previously unattainable.

Valence and core-level X-ray photoemission spectroscopy of light-sensitive molecules: Lumazine and alloxazine

Valence and core-level photoemission spectra of two gaseous nitrogen containing heterocycles, lumazine and alloxazine, have been studied experimentally and theoretically. Comprehensive information about the electronic structure of these aromatic molecules has been acquired. The outer-valence Green’s function (OVGF) approach was used to calculate vertical ionization energies and relative intensities (pole strengths) of the valence band spectra. The C, N, and O 1s core level spectra of both compounds were measured and assigned on the basis of Δ-Kohn–Sham calculations. The relative stability of different tautomers of lumazine and alloxazine was investigated through DFT calculations. Only the single, most stable tautomer for lumazine and alloxazine was populated at the present experimental conditions and this finding is confirmed by the core-level photoemission signal, which is able to discriminate between different isomers of a molecule. Other tautomers of lumazine and alloxazine have not been clearly identified spectroscopically, however their relative free energies and Boltzmann populations were calculated and compared with previous studies.

Amelioration of pathologic α-synuclein-induced Parkinson’s disease by irisin

Physical activity provides clinical benefit in Parkinson's disease (PD). Irisin is an exercise-induced polypeptide secreted by skeletal muscle that crosses the blood-brain barrier and mediates certain effects of exercise. Here, we show that irisin prevents pathologic α-synuclein (α-syn)-induced neurodegeneration in the α-syn preformed fibril (PFF) mouse model of sporadic PD. Intravenous delivery of irisin via viral vectors following the stereotaxic intrastriatal injection of α-syn PFF cause a reduction in the formation of pathologic α-syn and prevented the loss of dopamine neurons and lowering of striatal dopamine. Irisin also substantially reduced the α-syn PFF-induced motor deficits as assessed behaviorally by the pole and grip strength test. Recombinant sustained irisin treatment of primary cortical neurons attenuated α-syn PFF toxicity by reducing the formation of phosphorylated serine 129 of α-syn and neuronal cell death. Tandem mass spectrometry and biochemical analysis revealed that irisin reduced pathologic α-syn by enhancing endolysosomal degradation of pathologic α-syn. Our findings highlight the potential for therapeutic disease modification of irisin in PD.

Force-Distance Relation for Dental Magnets - Fitted Equation.

The force-distance power law for dental magnets had been unresolved until a theoretical study found that only even inverse powers were allowed; for simple magnets inverse fourth power was the only possibility. It remained to demonstrate that this indeed did apply to real magnets, the present purpose. The force exerted by a series of real dental magnets to a large steel plate, and in a few cases to dental magnet keepers, as a function of distance was recorded. Curve-fitting of that data was explored. using the equation previously used for long dipoles, but allowing the power to be a free parameter. An index of 4 was the only feasible value. Corresponding fitted parameter values were then examined in relation to magnet design and each other. The theoretical power law index was confirmed to be 4. For a satisfactory fit, a 'polar offset' and a 'stretch power' were again required to better approximate the experimental results. Polar offset appears to be a function of apparent pole strength; stretch power less clearly so. The motivating question is settled.

Outer-valence ionization of nitrous oxide: A high-resolution electron momentum spectroscopy investigation

We report a detailed study on the outer-valence ionization of nitrous oxide (N2O) by a high-resolution (e, 2e) spectrometer employing asymmetric non-coplanar kinematics at an impact energy of 2500 eV. Binding energy spectrum in the energy region of 11–30 eV is obtained. Benefiting from the high energy resolution of 0.55 eV, four main peaks and six satellite structures are clearly identified in this region. The measured electron momentum profiles are compared with the theoretical calculations. Renner-Teller-effect induced geometry distortion is used to qualitatively interpret the observed discrepancy at low momentum between experiment and theory for B2Π state. The assignments and the pole strengths for these ionization states are determined by comparing the shape and the intensity of the experimental electron momentum profiles with those of the theoretical ones. In particular, two low-lying satellites at 21.0 eV and 27.1 eV are confirmed for the first time and attributed to the 2Π and 2Σ shake-up states. The present results show the evidence of strong electron correlation effects in the final states for the outer-valence ionization of N2O.

Study on the Influence of Polymer/Particle Properties on the Resilience of Superhydrophobic Coatings.

Enhancement in the resilience of superhydrophobic coatings is crucial for their future applicability. However, the progress in this aspect is currently limited due to the lack of a consistent resilience analysis methodology/protocol as well as the limited understanding of the influence of the materials components on the resultant coating performance. This study applies a quantitative analysis methodology involving image analysis and mass tracking and utilizes it to investigate how the properties of coating components can influence coating resilience. The factors examined were changing the molecular weight/tensile strength of poly(vinylchloride)/poly(dimethylsiloxane) (PVC/PDMS) polymers and changing the size of the roughening particles. In addition to the examination of resilience data to evaluate degradation patterns, three-dimensional (3D) mapping of the scratches was performed to obtain an insight into how material removal occurs during abrasion. The results can indicate preferential polymer selection (using higher-molecular-weight polymers for PVC) and optimal particle sizes (smaller particles) for maximizing coating resilience. The study, although focused on superhydrophobic materials, demonstrates wide applicability to a range of areas, particularly those focused on the development of high-strength coatings.

Preparation and properties of high melt strength PBS and its environmentally friendly foaming materials

In order to improve the melt strength of Poly(butylene succinate) (PBS) resin, the silane graft-crosslinked PBS copolyester materials were prepared by melt blending method with vinyltriethyl silane as graft material and benzyl peroxide (BPO) as initiator. At the same time, the environmentally friendly compound foaming agent (citric acid and sodium bicarbonate) was used as foaming agent. The results showed that the tensile properties and melt strength of PBS resin were greatly improved after silane grafting and cross-linking, and the graft and cross-linking reaction between PBS resin and silane occurred, forming a three-dimensional space network structure, and the viscosity and elasticity of polymer melt was changed, which increased the entropy elasticity of the material and strengthened the polymer melt strength. The additional amount of compound foaming agent and the cross-linking degree of material had important influence on the diameter and distribution of PBS foaming material.

Intermediate state representation approach to physical properties of molecular electron-attached states: Theory, implementation, and benchmarking.

Computational schemes for comprehensive studies of molecular electron-attached states and the calculation of electron affinities (EAs) are formulated and implemented employing the intermediate state representation (ISR) formalism and the algebraic-diagrammatic construction approximation for the electron propagator (EA-ADC). These EA-ADC(n)/ISR(m) schemes allow for a consistent treatment of not only electron affinities and pole strengths up to third-order of perturbation theory (n = 3) but also one-electron properties of electron-attached states up to second order (m = 2). The EA-ADC/ISR equations were implemented in the Q-Chem program for Ŝz-adapted intermediate states, allowing also open-shell systems to be studied using unrestricted Hartree-Fock references. For benchmarking of the EA-(U)ADC/ISR schemes, EAs and dipole moments of various electron-attached states of small closed- and open-shell molecules were computed and compared to full configuration interaction data. As an illustrative example, EA-ADC(3)/ISR(2) has been applied to the thymine-thymine (6-4) DNA photolesion.

ΔSCF Dyson orbitals and pole strengths from natural ionization orbitals.

The calculation of photoionization cross sections can play a key role in spectral assignments using modeling and simulation. In this work, we provide formal relationships between pole strengths, which are proportional to the photoionization cross section, and terms related to the natural ionization orbital model for ΔSCF calculations. A set of numerical calculations using the developed models is carried out. Pole strength values computed using the two approaches developed for ΔSCF calculations demonstrate excellent agreement with an electron propagator theory model.

No Change - No Gain; The Effect of Age, Sex, Selected Genes and Training on Physiological and Performance Adaptations in Cross-Country Skiing.

The aim was to investigate the effect of training, sex, age and selected genes on physiological and performance variables and adaptations before, and during 6 months of training in well-trained cross-country skiers. National-level cross-country skiers were recruited for a 6 months observational study (pre – post 1 – post 2 test). All participants were tested in an outside double poling time trial (TTDP), maximal oxygen uptake in running (RUN-VO2max), peak oxygen uptake in double poling (DP-VO2peak), lactate threshold (LT) and oxygen cost of double poling (CDP), jump height and maximal strength (1RM) in half squat and pull-down. Blood samples were drawn to genetically screen the participants for the ACTN3 R577X, ACE I/D, PPARGC1A rs8192678, PPARG rs1801282, PPARA rs4253778, ACSL1 rs6552828, and IL6 rs1474347 polymorphisms. The skiers were instructed to train according to their own training programs and report all training in training diaries based on heart rate measures from May to October. 29 skiers completed all testing and registered their training sufficiently throughout the study period. At pre-test, significant sex and age differences were observed in TTDP (p < 0.01), DP-VO2peak (p < 0.01), CDP (p < 0.05), MAS (p < 0.01), LTv (p < 0.01), 1RM half squat (p < 0.01), and 1RM pull-down (p < 0.01). For sex, there was also a significant difference in RUN-VO2max (p < 0.01). No major differences were detected in physiological or performance variables based on genotypes. Total training volume ranged from 357.5 to 1056.8 min per week between participants, with a training intensity distribution of 90–5–5% in low-, moderate- and high-intensity training, respectively. Total training volume and ski-specific training increased significantly (p < 0.05) throughout the study period for the whole group, while the training intensity distribution was maintained. No physiological or performance variables improved during the 6 months of training for the whole group. No differences were observed in training progression or training adaptation between sexes or age-groups. In conclusion, sex and age affected physiological and performance variables, with only a minor impact from selected genes, at baseline. However, minor to no effect of sex, age, selected genes or the participants training were shown on training adaptations. Increased total training volume did not affect physiological and performance variables.

Form-invariant solution to quantum state on the sphere

This paper investigates the quantum states that emerge from the transformation design of conformal mapping on the two-dimensional sphere. Three results are reported. First, the construction of form-invariant spherical harmonics labelled by the fractional quantum number through a scalar potential interaction is given. Second, the form-invariant equation of the charge-monopole system is studied. Rather than the half-integer classification of the monopole harmonics, the quantization of the monopole harmonics here can be any fractional number specified by the conformal index. The gauge equivalent condition of the vector potentials which result in the invariant equation shows that the monopole field and the quantization condition of the pole strength due to Dirac can be generalized to more general vector fields and values in the conformal space. Finally, we explore the quadratic conformal image of the charged particle coupling to the constant monopole field on the sphere. It is shown that the lowest order approximation of the image is the magnetic Hooke-Newton transmutation.

How graphene oxide affects shape memory properties and strength of poly(l-lactide-co-ε-caprolactone)

Poly( l-lactide-co-ε-caprolactone) is an environment-friendly shape memory polymer. Molecular dynamics method was used to study the shape memory effect and mechanical properties of graphene oxide–reinforced poly( l-lactide-co-ε-caprolactone) to understand the microscopic mechanism. Two models containing dispersed graphene oxide were constructed. It is shown that the addition of graphene oxide causes the glass transition temperature of material to rise because of limitation on polymer activity. The uniaxial tensile properties of the composites were studied. The results exhibited that strength of composites depend on the interface state of the polymer and graphene oxide. The strength of the composite with covalent bond is much higher than that of another without the covalent bond between graphene oxide and poly( l-lactide-co-ε-caprolactone) generated. Stress softening effect was observed in the cross-linked composite in the glass state. Their uniaxial tension thermodynamic cycles were carried out to consider the shape memory effect of the composites. It is shown that graphene oxide–reinforced composites with different interactions exhibit fair shape memory effect in the direction of paralleling graphene oxide surface. In terms of the direction perpendicular to graphene oxide sheet, the fixed ratios of the composites decrease slightly about 1.64%–3.63%, and the recovery ratios of the composites with the covalent bond are higher than others about 3.22%–12.93%.

An All-Scale Hierarchical Architecture Induces Colossal Room-Temperature Electrocaloric Effect at Ultralow Electric Field in Polymer Nanocomposites.

Composed of electrocaloric (EC) ceramics and polymers, polymer composites with high EC performances are considered as promising candidates for next-generation all-solid-state cooling devices. Their mass application is limited by the low EC strength, which requires very high operational voltage to induce appreciable temperature change. Here, an all-scale hierarchical architecture is proposed and demonstrated to achieve high EC strength in poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)-based nanocomposites. On the atomic scale, highly polarizable hierarchical interfaces are induced by incorporating BiFeO3 (BFO) nanoparticles in Ba(Zr0.21 Ti0.79 )O3 (BZT) nanofibers (BFO@BZT_nfs); on the microscopic scale, percolation of the interfaces further raises the polarization of the composite nanofibers; on the mesoscopic scale, orthotropic orientation of BFO@BZT_nfs leads to much enhanced breakdown strength of the nanocomposites. As a result, an ultrahigh EC strength of ≈0.22 K m MV-1 is obtained at an ultralow electric field of 75 MV m-1 in nanocomposites filled with the orthotropic composite nanofibers, which is by far the highest value achieved in polymer nanocomposites at a moderate electric field. Results of high-angle annular dark-field scanning transmission electron microscopy, in situ scanning Kelvin probe microscopy characterization, and phase-field simulations all indicate that the much enhanced EC performances can be attributed to the all-scale hierarchical structures of the nanocomposite.

Anti-neuroinflammatory effects of Eucommia ulmoides Oliv. In a Parkinson's mouse model through the regulation of p38/JNK-Fosl2 gene expression

Ethnopharmacological relevanceEucommia ulmoides Oliv., a Chinese medicinal herb called “Duzhong” from the bark of Eucommia ulmoides Oliv., has been shown to possess significant protective effects in Parkinson's disease (PD). However, the molecular mechanism remains unclear. Aim of the studyIn this study, we explored the anti-neuroinflammatory mechanisms of Duzhong on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model to elucidate the traditional medical theories with modern pharmacological methods and to provide a reference for further clarifying its mechanisms of action. Materials and methodsThe representative components in Duzhong extract were identified by UPLC-Q-TOF/MS. Male C57BL/6J mice were intraperitoneally injected with MPTP to establish an in vivo PD model. The pole, rotarod, and grip strength tests were performed to evaluate the motor coordination ability of the PD mice. HPLC-ECD was used to detect the striatal levels of dopamine (DA), 3,4- dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). The expression of tyrosine hydroxylase (TH) was studied by immunohistochemistry (IHC) and Western blot assays. ELISA and Q-PCR were used examined the levels of proinflammatory cytokines in the serum and midbrain, respectively. Whole-transcriptome analysis of the midbrain was performed to explore the therapeutic effect of Duzhong on PD mice, and Q-PCR was then used to validate the differential gene expression changes in the PD mice treated with Duzhong. ResultsTen compounds were identified from Duzhong extract. Duzhong significantly alleviated the behavioral impairments and dopaminergic neuron degeneration of PD mice, and inhibited the expression of proinflammatory cytokines. Whole-transcriptome analysis revealed nine oppositely regulated genes, and the Fosl2 gene was consistent with the trend of observed by RNA-seq. Furthermore, Duzhong downregulated mRNA expression of p38 and JNK, which are key upstream genes of Fosl2. ConclusionsDuzhong has promising therapeutic potential in PD mice, and its molecular mechanism is mediated by downregulating p38/JNK-Fosl2 gene expression to alleviate neuroinflammation.

Optimization of Condition-Based Maintenance of Wood Utility Pole Network Subjected to Hurricane Hazard and Climate Change

Electric power distribution systems that link the bulk power grid (generation and transmission systems) to customers are the leading cause of power outages due to their vulnerability to extreme wind events, especially hurricanes. The strength of the wood poles that typically support the distribution lines also deteriorate over time. The vulnerability of the poles is expected to increase due to the potential impact of climate change on both hurricane hazard and wood decay rate. As such, an effective maintenance planning method is required for the vast number of poles supporting distribution lines. This paper presents a framework to optimize the maintenance of a network of wood utility poles. Corrective replacement due to failure caused by hurricanes and preventive replacement due to excessive decay are considered. The objective is to find the optimal inspection interval for the preventive replacement to minimize the long-term maintenance cost. To solve the optimization problem, the decay of the poles is modeled as a stationary gamma process. The impact of climate change on the rate of pole failure and replacement is also investigated. Two locations are considered as case studies: Miami, Florida, and New York City, New York. The period from 2010 to 2099 is considered for the study. The results of the case study show that the optimal inspection/replacement cycle determined using the developed framework results in lower total maintenance costs compared to current typical utility practice. Based on the inspection and replacement costs used in the study, the results show that adopting a periodic preventive maintenance policy decreases the failure rate of the poles but increases the total maintenance cost. However, only the cost of replacing the poles is considered here. Other considerations, such as indirect costs due to power outages and the impact of pole failure on system reliability, can render the adoption of a preventive replacement policy cost-effective. The results also show that climate change can increase the total maintenance cost. Based on current typical utility maintenance practice, climate change can increase the total maintenance cost by up to 8% in Miami and 6% in NYC, depending on the emission scenario considered.

Reliability Assessment of Electrical Grids Subjected to Wind Hazards and Ice Accretion with Concurrent Wind

The supportive structures of power grids are vital but susceptible to weather-related events, such as extreme wind and icing rain with concurrent wind. The objective of this paper is to assess the reliability of the power grids subjected to high wind and ice accretion. The material and geometry uncertainty and the strength deterioration of poles due to decay are included in probabilistic models considering the bending failure of the poles and tensile failure of the wires. The extreme wind speed and icing accretion thickness are modeled with the Weibull distribution and generalized Pareto distribution, respectively. The fragility and reliability are analyzed with a Monte Carlo simulation for the comparison of two example locations with different hazard conditions. Case studies are implemented with a notional system and the system of Centerville, a fictitious study domain. The results illustrated that the fragility of wires is noteworthy in icing hazard reliability assessment. During icing rain, the concurrent wind speed significantly impacts the reliability of the power grids. The system reliability subjected to wind hazards is more sensitive to pole strength deterioration than in icing scenarios. The presented analysis framework will be beneficial for the design and maintenance of power grids subjected to both wind and icing hazards.

Precise Feshbach resonance spectroscopy using tight anharmonic traps

Feshbach resonances are among the essential control tools used in ultracold atom experiments. However, for complex atomic species the theoretical characterization of resonances becomes challenging. For closely spaced resonances, the measurement of three-body losses does not provide sufficient resolution to discriminate them. For this reason, resonance spectroscopy of trapped isolated atoms is becoming the state of the art. Here we show that trapping the atoms in a double well potential such as an optical lattice or a pair of optical tweezers enables precise characterization of not only the resonance position and width, but also its pole strength, giving valuable information about the atomic structure relevant for subsequent many-body studies.