Empirical Relationship Research Articles

A panel data study on the role of clean energy in promoting life expectancy.

Energy is a health issue. Energy intersects with health outcomes, as evidenced by the relationship between access to clean fuels and technologies and population health measured by life expectancy at birth. Utilizing a comprehensive dataset spanning 190 countries from 2000 to 2022, this paper employs a range of static and dynamic panel data models to analyze this empirical relationship, while effectively managing unobserved country-specific heterogeneity and endogeneity issues. The primary finding underscores that improved access to clean fuels and technologies positively correlates with increased life expectancy for both genders, males and females, on a global scale. Additionally, the study identifies a significant negative impact of food and nutritional deficiencies on human health, while highlighting positive associations between health outcomes and increased per capita health spending, immunization rates, education levels, and access to safe drinking water and sanitation facilities. Findings underscore the importance of policy interventions aimed at alleviating clean energy poverty and scaling up access to clean fuels and technologies to enhance both the duration and quality of life, thus fostering sustainable development efforts at both national and global levels.

Evaluation of empirical relationships in carbonates by developing a 1D mechanical earth model in an oil field in Southwestern Iran

Evaluation of empirical relationships in carbonates by developing a 1D mechanical earth model in an oil field in Southwestern Iran

Band together or go it alone? Climate risk and corporate collaborative innovation

Corporations are under increasing pressure to adapt their strategies to mitigate the adverse effects of climate risk. This study explores the theoretical and empirical relationship between climate risk and corporate collaborative innovation, highlighting the mechanisms involved. Theoretical analysis suggests that climate risk, by intensifying stranded assets and cross-risks, acts as a compensatory driver for collaborative innovation among corporations. Digital transformation strengthens this compensatory mechanism, while corporate risk-taking diminishes its impact. Empirical analysis using data from Chinese A-share listed companies supports the theoretical framework, revealing that climate risk compels companies to “band together” for technological advancement to manage external challenges. The mediating effect of digital transformation enhances the flow of innovation elements among firms, bolstering collaborative innovation, whereas risk-taking weakens this effect. This paper deepens the understanding of how climate risk shapes corporate strategy. It provides practical insights for corporate strategists seeking collaborative responses to environmental volatility and supports policymakers in designing sustainability-oriented policies.

The Choice among Sales Mechanisms: Auction v. Negotiated Sales of Private Timber

Abstract For many non-industrial private forest (NIPF) landowners, the standing timber on their property is an important component of their investment portfolios. The value of their timber is determined not only by the biological and physical attributes of their timber tracts, but also by the transaction costs associated with different contracting practices, pricing schemes, and sales mechanisms. In this paper, we examine the determinants of the choice by landowners between the two predominant sales mechanisms for selling standing timber—auctions and negotiations. Our examination provides industry participants with a framework for thinking about the benefits and costs of the choice between these two alternatives. Further, it provides them with information on empirical relationships among sales mechanisms and their determinants. We also discuss potential implications of our results for the USDA Forest Service (Forest Service), which is required to sell almost all of its tracts through auctions.

Decoupling both local and global abundance from global range size, challenging the abundance-occupancy relationship in birds.

In macroecology, a classic empirical observation has been positive relationships between local abundance and species' range, known as the abundance-occupancy relationships (AORs). The existence of this empirical relationship has informed both theory development and applied questions. Notably, the spatial neutral model of biodiversity predicts AORs. Yet, based on the largest known meta-analysis of 16,562,995 correlations from ~3 billion bird observations, this relationship was indistinguishable from zero. Further, in a phylogenetic comparative analysis, species range had no predictive power over the global mean abundance of 7464 bird species. We suggest that publication and confirmation biases may have created AORs, an illusion of a 'universal' pattern. This nullification highlights the need for ecologists to instigate a credibility revolution like psychology, where many classic phenomena have been nullified.

Decoupling both local and global abundance from global range size, challenging the abundance-occupancy relationship in birds

In macroecology, a classic empirical observation has been positive relationships between local abundance and species’ range, known as the abundance-occupancy relationships (AORs). The existence of this empirical relationship has informed both theory development and applied questions. Notably, the spatial neutral model of biodiversity predicts AORs. Yet, based on the largest known meta-analysis of 16,562,995 correlations from ~3 billion bird observations, this relationship was indistinguishable from zero. Further, in a phylogenetic comparative analysis, species range had no predictive power over the global mean abundance of 7464 bird species. We suggest that publication and confirmation biases may have created AORs, an illusion of a ‘universal’ pattern. This nullification highlights the need for ecologists to instigate a credibility revolution like psychology, where many classic phenomena have been nullified.

Self-Regulation, Academic Performance and Psychological Well-Being among University Students

The purpose of the present study was to establish an empirical relationship between self-regulation, psychological well-being, and academic performance in university students. The study involved 350 university students, aged between 18 and 30 years (mean age=20.59, standard deviation=1.86). Three assess instruments were applied and these include The Short Self- Regulation Scale, Ryff’s Scales of Psychological Well-Being and the Academic performance Scale. It was found that there exists a linkage between self-regulation of students, their psychological Wellbeing, and academic achievement. Hence, research concludes that self-regulation and overall psychological health have a greater impact on the academic capability of university learners.

Microscopic Air–Water Properties in Non-Uniform Self-Aerated Flows

Supercritical open channel flows contribute substantially to the air–water transfer process in spillways, rivers, and streams. They are characterized by strong turbulent mixing and a substantial amount of air entrainment. The microscopic air–water properties in non-uniform self-aerated flows are investigated experimentally with various chute slopes, including air chord size and air–water transfer frequency. Microscopic air–water structures are primarily affected by chute slope, whereas the approach flow Reynolds number hardly influences them, resulting in self-similarity of the probability distribution of air chord length and air–water transfer frequency distribution in the self-aerated region. The distribution of bubble chord length is more continuous from the small to large scale in the high-air-concentration region for a greater chute slope, and the position of maximum air frequency moves to the higher-aeration zone and gets closely to the free surface. Moreover, empirical relationships are provided to predict the microscopic air–water properties in non-uniform self-aerated flows.

Breaking the Hardness-Wear Trade-Off: Quantitative Correlation in Nano-Al2O3-Reinforced Al10Cr17Fe20NiV4 High-Entropy Alloys.

Multi-principal element alloys (MPEAs) exhibit distinct characteristics compared to conventional single-principal element-based metallic materials, primarily due to their unique design, resulting in intricate microstructural features. Currently, a comprehensive understanding of the fabrication processes, compositional design, and microstructural influence on the tribological and corrosion behavior of multi-component alloys remains limited. While the hardness of MPEAs generally correlates positively with wear resistance, with higher hardness typically associated with improved wear resistance and reduced wear rates, quantitative relationships between these properties are not well established. In this study, the Al10Cr17Fe20NiV4 alloy was selected as a model system. A homogeneous Al10Cr17Fe20NiV4 alloy was successfully synthesized via mechanical alloying followed by spark plasma sintering (SPS). To further investigate the correlation between hardness and wear rate, varying concentrations of alumina nanoparticles were incorporated into the alloy matrix as a reinforcing phase. The results revealed that the Al10Cr17Fe20NiV4 alloy exhibited a single-phase face-centered cubic (FCC) structure, which was maintained with the addition of alumina nanoparticles. The hardness of the Al10Cr17Fe20NiV4 alloy without nano-alumina was 727 HV, with a corresponding wear rate of 2.9 × 10-4 mm3·N-1·m-1. The incorporation of nano-alumina increased the hardness to 823 HV, and significantly reduced the wear rate to 1.6 × 10-4 mm3·N-1·m-1, representing a 45% reduction. The Al2O3 nanoparticles effectively mitigated alloy wear through crack passivation and matrix strengthening; however, excessive addition reversed this effect due to the agglomeration-induced brittleness and thermal mismatch. The quantitative relationship between hardness (HV) and wear rate (W) was determined as W = 2348 e(-0.006HV). Such carefully bounded empirical relationships, as demonstrated in studies of cold-formed materials and dental enamel, remain valuable tools in applied research when accompanied by explicit scope limitations.

Exploring and refining testing approaches for hardwood dowels under axial and flexural loading: an experimental and numerical study

ABSTRACT The widespread use of metal fasteners and adhesives in engineered wood products raises concerns regarding end-of-life disposal, recyclability, reusability, health implications, and sustainability. Dowel-laminated timber has emerged as an efficient alternative, addressing these challenges. However, the mechanical characterisation of wooden dowels, the primary connectors in dowel-laminated timber systems, remains largely unexplored. The properties of dowels differ from the sawn timber from which they are derived due to machining, their cylindrical shape, and limited transverse dimensions. This necessitates independent testing to determine their mechanical properties. Currently, no standardised testing protocols exist specifically for wooden dowels, and their small size and round geometry pose challenges for mechanical testing. In this study, Australian Tasmanian oak and eucalyptus grandis dowels were tested under bending, tension, and compression, both parallel and perpendicular to grain. Relevant literature was critically analysed to evaluate the applicability of existing testing methods to wooden dowels, with recommendations proposed to address their unique requirements. Empirical relationships were developed for various mechanical properties. Furthermore, advanced numerical modelling was performed using the MAT-143 material model in LS-DYNA, which accurately captures post-elastic behaviour. The findings demonstrated that the testing methodologies, presented in this study are applicable for evaluating the mechanical behaviour of wooden dowels.

Empirical relations using symbolic regression models for cluster decay half-lives

Empirical relations using symbolic regression models for cluster decay half-lives

Size-Controllable Synthesis of Cu Nanoparticles via Hydrogen Reduction at Low Temperatures.

The general polyol methods used for synthesizing copper nanoparticles (CuNPs) usually require high temperatures to ignite the reduction reaction, which leads to the difficulty of controlling the particle size. Herein, a new polyol method for the size-controllable synthesis of CuNPs at low temperatures by adopting high-pressure hydrogen as the reductant is verified. It is proven that hydrogen is capable to reductively produce CuNPs at temperatures as low as 120 °C. The size of the CuNPs can be controlled between 19.29 nm and 140.46 nm by adjusting the hydrogen pressure, the reaction temperature, and duration. An empirical relationship between temperature and particle size is proposed. This work verifies a low-temperature strategy to synthesize nanoparticles with good size-controllability.

Strength experimental studies of multi-cavity floor slabs support sections in platform joints, taking into account partial pinching

Domestic standards for large-panel buildings design contain a methodology for calculating multi-cavity floor slabs in platform joints support sections, considering the effect of their partial pinching in walls. The calculation method is based on empirical relationships and does not take into account various factors that can significantly affect the stress-strain state of a join in general and a slab support section in particular. These include joint compression level, as well as the slab support depth. Since the specified features of the existing methodology can lead to incorrect assessment of the multi-cavity slabs supporting sections bearing capacity, experimental studies of platform joints with multi-cavity slabs at various compression levels, as well as sealing depths, have been carried out. When analyzing the test results, it was found that bearing capacity theoretical values calculated according to standard methods do not exceed the actual cracking moment values for most samples. This fact indicates that the methods under consideration assume sufficiently large safety margins. It is established that the magnitude of experimental negative bending moment that occurs on the slab support sections under load at the stage of a crack appearance on the support, considering the free support actual reaction, can reach the values of the theoretical moment obtained according to elastic scheme for support rigid pinching.

Experimental study of heat transfer to air flowing through an inclined porous duct

AbstractInclined duct has many engineering applications like air conditioning system, solar collector and cooling system of photovoltaic module. Forced convection of air flowing through an inclined square porous duct is described in this paper. The experiments by varying Reynolds number, heat flux and inclination angle have been conducted under Reynolds number at 8355, 13485 and 18600 range, heat flux 480, 990 and 1520 W m−2 and inclination duct angle 30°–60°. The porous pad used was zig-zag metallic wire mesh with porosity equals 0.99. The results show that Nusselt number is increased with increasing heat flux and Reynolds number at all orientations. At the same Reynolds number and heat flux, Nusselt number is enhanced about 4.7% with increasing inclination angle from 30° to 60°. Nusselt number is to be 24%, 21% higher than horizontals porous duct at inclination angle 60°–30°, respectively. Many empirical relations have been obtained.

A short version of Perceived Destination Restorative Quality Scale (PDRQS): empirical structure and relationship with tourist satisfaction

ABSTRACT Applied context research, such as tourism, requires tools that minimize data collection time without sacrificing statistical rigour. The aim of this study is to develop a short version of the Perceived Destination Restorative Quality Scale (PDRQS), developed by XInran Lehto in 2013, and examine its relationship with tourist satisfaction to assess nomological validity. Study 1 involved 454 people completing the PDRQS and the Tourist Satisfaction and Enjoyment Scale developed by Jianyu Ma, Noel Scott, Jun Gao, and Peiyi Ding in 2017 in relation to the last tourist site visited. Results confirm a two-factor model for the short version of PDRQS, with one general factor and five specific factors. In Study 2, 2036 tourists responded to the short version of the PDRQS and the Tourist Satisfaction and Enjoyment Scale, in a survey, at the end of their tourist visit to one of three different sites of Tenerife: a mountainous area, a swimming pool and an urban seafront promenade. Results show an appropriate fit for the 16-item PDRQS, and optimal reliability ratings. The invariance of the model was checked by tourist site visited. Finally, the general factor of restorative qualities explains 73% of the variance in tourist satisfaction. These findings contribute to the literature by presenting a more concise scale with good fit indices.

Mechanically Tunable DNA Hydrogels as Prospective Biosensing Modules.

Sequence-programmable DNA building blocks offer high degree of freedom in designing arbitrarily complex networks of tunable viscoelastic properties. Yet, the deployment of DNA-based functional materials remains limited due to insufficient control over the emerging structures and their mechanics. In an ongoing effort to place structure-property relations in stimuli-responsive DNA materials on a firm foundation, here a systematic rheological study of self-assembling DNA networks is presented, comprised of short DNA nanomotifs, namely trivalent nanostars and bivalent linkers, where the latter differ in their composition on a single base-pair level. Notably, we found through combining conventional bulk rheology with diffusing wave spectroscopy (DWS-based) passive microrheology a relationship between the melting temperature of a DNA hydrogel and its DNA sequence composition. By providing a use case, we demonstrated how the determination of such empirical relations could impact the areas of biosensing and mechanical computing, where control over the system state and target identification arekey.

On single-station, six degree-of-freedom observations of local to regional seismicity at the Piñon Flat Observatory in Southern California

In September 2022, a portable, three-component rotational rate sensor, namely a blueSeis-3A gyroscope, has been deployed at the underground vault of the Pinon Flat Observatory (PFO) in southern California. A three-component, broadband seismometer is co-located, jointly forming a six degree-of-freedom (DoF) station for long-term observations of local and regional seismicity and multi-component wavefield studies. The seismic recordings are available online via IRIS FDSN services as PY.BSPF (BlueSeis at Pinon Flat). The instrumentation at PFO additionally provides high-quality strain observations, allowing now to study translation, rotations and strain of the seismic wavefield in a low noise and high seismicity area (e.g. San Andreas fault zone). The seismic array at PFO is used to compute array derived rotations and validate the direct observations of rotational ground motions. We show results of 6-DoF processing applied to a local Mw 4.1 and a regional Mw 6.2 event to obtain backazimuth estimates, which we validate with array beamforming, and estimates of local seismic phase velocities. For observed events between October 2022 and October 2023, we detect more than 400 events of which 118 are triggered on all six components. Peak rotation rate amplitudes are used to derive empirical peak amplitude relations for vertical and horizontal rotation rates to provide valuable insights towards resolvability for comparable 6~DoF campaigns. We find the dominating limitations for rotational motion observations currently to be set by the self-noise level of the blueSeis-3A rotation sensor and encourage further instrumental development.

Empirical relationship between the Geological Strength Index (GSI) and rock mass quality (Q-system) in granite and sedimentary rocks

This paper presents the relationship between Rock Mass Quality (Q-system) and the Geological Strength Index (GSI) parameters. Equations are suggested based on field data and calculations of the empirical results of granitic rock masses (Hungary) and siltstones, sandstones and quartzite formations (Australia). Measured and calculated GSI values vs Q values are given for granitic rocks, showing a higher correlation than that of the sedimentary rocks of Australia. The different behaviors of rock masses explain the higher correlation between GSI vs Q and GSI chart vs GSI calculated for igneous rock bodies. Despite the differences in stress fields and the highly tectonised structural geological setting of the granitic rock mass, the isotropic nature of granitic rocks vs. anisotropy of sedimentary rock bodies is reflected in the correlation coefficients.

Benchmark stars for mean stellar density and surface gravity estimates of solar-type stars

ABSTRACT Adding an independent estimate of the mean stellar density, $\rho _{\star }$, as a constraint in the analysis of stars that host transiting exoplanets can significantly improve the precision of the planet radius estimate in cases where the light curve is too noisy to yield an accurate value of the transit impact parameter, e.g. the light curves of Earth-size planets orbiting in the habitable zone of Sun-like stars that will be obtained by the PLAnetary Transits and Oscillations of stars (PLATO) mission. I have compiled a sample of 36 solar-type stars for which analysis of high-quality light curves together with constraints on the orbital eccentricity yield mean stellar density measurements with a median error of 2.3 per cent. Of these, 8 are in transiting exoplanet systems and 28 in eclipsing binary systems with very low mass companions that contribute <0.1 per cent of the total flux in the V band. A recalibrated empirical relation for stellar mass as a function of T$_{\rm eff}$, $\rho _{\star }$, and [Fe/H] has been used to find mass estimates with a typical precision of 5.2 per cent for the stars in this sample. Examples are given of how this sample can be used to test the accuracy and precision of $\rho _{\star }$ and $\log g$ estimates from catalogues of stellar parameters for solar-type stars.

Modelling the impact of emotional intelligence on academic performance: A conceptual and empirical approach in higher education

ABSTRACT Universities develop students’ emotional intelligence-oriented education strategies to gain competitiveness in academic delivery. Formulation of those strategies requires empirical insights into students’ emotional intelligence. This paper attempts to develop a conceptual model that advocates the impact of students’ emotional intelligence (Emotional Quotient/EQ) on their educational achievement using an empirical model. The model proposes direct and indirect pathways influencing cognitive, social, and self-growth outcomes. By analysing critical secondary data (from 2005 to 2023), the researchers have explored the empirical relationship between students’ EQ and academic performance. The findings reveal that EQ is a positive, desirable, and realistic academic phenomenon across various disciplines, teaching methods, and academic settings. The study suggests that students’ EQ significantly influences their academic performance and outcomes, such as pursuing higher grades, gaining subject knowledge, active engagement, and real-world learning. This research aids universities, students, and organisational leaders in examining, determining, and regulating students’ EQ.