The appearance of a topic in a document stream is signaled by a burst of activity, with certain features rising sharply in frequency as the topic emerges. Although temporal bar graph (TBG) is ...frequently applied to present the burst spot in the bibliographical study, none of the research has combined the inflection point (IP) to interpret the burst spot feature. The aims of this study are to improve the traditional TBG and apply the TBG to understand better the evolution of a topic (e.g., publications and citations for a given author).
The EISTL model, including entity, indicator, selection of a few vital ones (named attributes) with higher values in quantity (e.g., the citation data of the top 10 entities), TBG and line-chart plots to verify the trend of interest, was proposed to demonstrate the TBG as a whole. The IP locations compared to the median point in data along with the heap map and line-chart trend were identified. The burst strength was computed. A dashboard on Google Maps was designed and launched for bibliometric analysis. Four authors in MDPI (Multidisciplinary Digital Publishing Institute) journals named to be Citation Laureates 2021 were recruited to compare their research achievements shown on the TBG, particularly displaying the burst spots and the recent developments and stages (e.g., increasing, ready to increase, slowdown, or decreasing).
We observed that the highest burst strengths in publication and citations are earned by Barry Halliwell (8.99) and Jean-Pierre Changeux (18.01). The breakthrough of TBG using the EISTL model to display the influence of authors in academics was made with 2 parts of the primary IP point and the trend feature in the data.
The dashboard-type TBG shown on Google Maps is unique and innovative and able to provide deeper insights to readers, not merely limited to the publications and citations for a given author as we did in this study.
This paper proposes an approach to assess the structural reliability of corroded pipes with calibrated strength models that reduce the subjectivity in model selection and incorporates their ...uncertainty. The approach calibrates and assesses the structural safety of pipes based on 25 burst strength models for corroded pipelines that are categorized into three classes of steel grades, i.e., low (X42 or less to X56), medium (X60 to X70) and high strength (X80 to X120). Statistical parameters such as the absolute mean error and standard deviation are adopted to analyse and compare the strength models’ performance against test results. Then, model uncertainties factors are derived and probabilistically characterized for each strength model. The importance of this methodology is demonstrated using a case study of one corroded pipe in each category of steel grade. The top 10 models from each steel pipe category are used for structural reliability evaluation. The First Order Reliability method is then employed for reliability and sensitivity assessments. Finally, partial safety factors are estimated by the best model in each steel category and compared with available codes. The proposed approach is believed to improve upon the existing methods by adopting the most accurate strength model and accounting for model uncertainties for different steel grades derived from test data and model predictions.
•This paper proposes an approach to assess the structural reliability of corroded pipes with calibrated strength models.•25 burst strength models are calibrated and used to assesses the structural safety of corroded pipelines.•Model uncertainties factors are derived and probabilistically characterized for each strength model.•The top 10 models from each of three steel pipe categories are used for structural reliability evaluation.•partial safety factors are estimated by the best model in each steel category and compared with available codes.
In the present study, starch was isolated from a non-conventional source (water chestnut) and various physicochemical properties were investigated. Nano starch was prepared by adopting the acid ...hydrolysis method having a yield of 27.5%. Particle size distribution of native and nano starch was 5559 nm and 396 nm. The unique feature of water chestnut starch was the shape of starch granule that looked oval, ellipsoidal, mixed with spherical granules without cracks and smooth surface. While the water chestnut nano starch appeared as an agglomerated form with irregular and rough surface. Water chestnut starch nanocomposites films with varying concentrations of starch nanoparticles (SNPs) were synthesized by a solution casting method. The thickness, moisture content, water vapour transmission rate, water solubility, burst strength of native starch and nano starch composite films were evaluated. The results showed that native starch film had thickness (0.041 ± 0.07 mm) moisture content (4.17 ± 0.32%), water vapour transmission rate (4.678 × 10−3 ± 0.42 g−2 s−1), water solubility (35.71 ± 0.17%) and burst strength (976.4 ± 12.47 g), respectively. The incorporation of SNPs results in an increase in thickness and burst strength while moisture content, water vapour transmission rate and solubility of films were decreased with the increase in the concentration of SNPs which is essential features of a good package.
•Water chestnut nano starch was characterized by Dynamic light scattering and Field Emission- Scanning Electron Microscopy•Nano starch based composite films were developed by adding 0.5, 1, 2, 5 and 10% nano starch in native starch.•Thickness, solubility, WVTR and burst strength were improved due to the addition of nano starch for development of films.
Exponential-like infection growth leading to peaks (denoted by inflection points IP or turning points) is usually the hallmark of infectious disease outbreaks, including coronaviruses. To determine ...the IPs of the novel coronavirus (COVID-19), we applied the item response theory model to detect phase transitions for each country/region and characterize the IP feature on the temporal bar graph (TBG).
The IP (using the item difficulty parameter to locate) was verified by the differential equation in calculus and interpreted by the TBG with 2 virtual and real empirical data (i.e., from Collatz conjecture and COVID-19 pandemic in 2020). Comparisons of IPs, R2, and burst strength BS = ln() denoted by the infection number at IP(Nip) and the item slope parameter(a) in item response theory were made for countries/regions and continents on the choropleth map and the forest plot.
We found that the evolution of COVID-19 on the TBG makes the data clear and easy to understand, the shorter IP (=53.9) was in China and the longest (=247.3) was in Europe, and the highest R2 (as the variance explained by the model) was in the US, with a mean R2 of 0.98. We successfully estimated the IPs for countries/regions on COVID-19 in 2020 and presented them on the TBG.
Temporal visualization is recommended for researchers in future relevant studies (e.g., the evolution of keywords in a specific discipline) and is not merely limited to the IP search in COVID-19 pandemics as we did in this study.
Zirconia-toughened alumina ceramic was introduced as a femoral head material for total hip arthroplasty. The material combines the stability of alumina with the toughness of zirconia. Despite ...inherent benefits for bearing surfaces, concern exists in the medical field that phase transformation of the zirconia grains could worsen wear resistance and lower the strength of the head. We examined these concerns in retrieved and artificially aged ceramic heads.
Twenty-eight ceramic composite heads retrieved at revision surgery were combined with 5 pristine heads (as negative controls for phase transformation) and 5 artificially aged pristine heads (as positive controls). The extent of zirconia phase transformation at the bearing surfaces was examined through confocal Raman spectroscopy and X-ray diffraction. Burst testing was conducted on all pristine and aged heads and the 4 retrieved implants with the longest lengths of implantation.
Retrieved heads had higher maximum average volume fractions of the monoclinic phase compared to pristine or aged heads. Length of implantation was not correlated to the volume fraction of the monoclinic phase. All the heads achieved a burst load far above the 46 kN Food and Drug Administration acceptance criterion; 3 of the 4 retrieved heads had burst strengths exceeding 100kN.
Our results showed that phase transformation occurs in vivo in ceramic composite femoral heads, but the amount transformed did not increase with the length of time the head had been implanted. The negligible effect upon burst strength of the retrieved and artificially aged heads is reassuring. These results support continued clinical use of this alumina-zirconia composite material as a head material.
To provide a basis for selecting formulas or extending their applied ranges,applying probability theory and mathematical statistics,a comparison and evaluation method of formula stability and ...precision was established. Based on the study that the ratio of actual burst pressure to the formula calculated value was basically in accordance with the normal distribution random variables, comparing and evaluation the formula stability from the variation coefficient of distribution parameters fluctuation range,comparing and evaluation the formula precision from the distribution parameters value interval contact ratio.When the bilateral confidence was 98% and in the applied range of the formula,the stability and precision of Mid-diameter formula,Tresca formula,Faupel formula and Rheological stress formula were compared and evaluated. The researching results shown that:（ 1） It is the basic conditions for selecting formulas or extending their applied ranges that stability and precision not reduced.（ 2） For pressure-bear
Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep wells. This paper aims to predict the casing burst strength with considerations of both ...wear and corrosion. Firstly, the crescent wear shape is simplified into three categories according to common mathematical models. Then, based on the mechano-electrochemical (M-E) interaction, the prediction model of corrosion depth is built with worn depth as the initial condition, and the prediction models of burst strength of the worn casing and corroded casing are obtained. Secondly, the accuracy of different prediction models is validated by numerical simulation, and the main influence factors on casing strength are obtained. At last, the theoretical models are applied to an ultra-deep well in Northwest China, and the dangerous well sections caused by wear and corrosion are predicted, and the corrosion rate threshold to ensure the safety of casing is obtained. The results show that the existence of wear defects results in a stress concentration and enhanced M-E interaction on corrosion depth growth. The accuracy of different mathematical models is different: the slot ring model is most accurate for predicting corrosion depth, and the eccentric model is most accurate for predicting the burst strength of corroded casing. The burst strength of the casing will be overestimated by more than one-third if the M-E interaction is neglected, so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.
The failure of corroded ultra-high-strength steel (X100 and X120) pipelines under combined axial loads and internal pressure is investigated numerically by finite element analyses, and an empirical ...model is proposed for burst strength prediction. The finite element structural models are constructed with uniformly oriented axial defects and consider material non-linearity. After validating the finite element models against test data of intact and corroded ultra-high-strength pipes, they are used to study the effect of axial tensile force on burst strength. Extensive parametric analyses are then conducted to investigate the influence of corrosion defect parameters on the burst strength under combined loading. The results revealed that both axial tension and corrosion defect can significantly reduce the burst strength of UHS pipe. Later, the results of the parametric analysis are used to develop an empirical model for burst strength prediction of ultra-high-strength steel corroded pipelines subjected to combined loading. Finally, the model's prediction capability is validated by comparisons with other available models.
•The failure of corroded X100 and X120 pipelines under combined axial loads and internal pressure is investigated.•The FE models are built with uniformly oriented axial defects and material non-linearity.•The FE models were validated against test data of intact and corroded ultra-high strength pipes.•Extensive parametric analyses are then conducted to investigate the influence of corrosion defect parameters.•The results of the parametric analysis are used to develop an empirical model for burst strength prediction.
Casing wear is a serious problem affecting casing integrity and casing strength, especially in ultra-deep wells, directional wells and horizontal wells. After casing is worn, degraded casing strength ...will lead to such hazardous problems as casing deformation, sustained casing pressure and even casing failure. Therefore, it is crucial and meaningful to predict residual casing strength and design casing string considering wear effect. Residual strength calculation model of worn casing, however, is still a challenge in casing design and safety evaluation. The purpose of this paper is to explore a simple and accurate model to predict the residual burst strength of crescent-shaped worn casing. The most commonly used mathematical models are discussed and compared in this paper. Through investigation and derivation, it is found that API (American Petroleum Institute) standard model assumes a uniform wear reduction around casing inner wall, while eccentric wear model simplifies worn casing as an eccentric pipe in bipolar coordinate. Then this paper presents a crescent-shaped wear model based on the force balance and moment balance of crescent-shaped worn casing. Finite element analysis proves that crescent-shaped wear model is more rigorous and accurate for residual burst strength prediction of worn casing. The work presented in this paper can provide a theoretical foundation and technical basis for casing wear evaluation and casing string design in directional wells.
•A mathematical model for to predict the residual burst strength of crescent-shaped worn casing is established.•The most commonly used mathematical models are discussed and compared.•Finite element analysis is carried out and the distribution of hoop stress is studied.•Crescent-shaped wear model is more rigorous and accurate for residual burst strength prediction of worn casing.
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