scholarly journals From Colour Catcher® to colorimetric sensors: disposable and cheap devices for inorganic ions determination

2021 ◽  
Vol 16 (2) ◽  
pp. 93-102
Author(s):  
Giancarla Alberti ◽  
Sofia Callegari ◽  
Ilaria Concardi ◽  
Lorenzo Ronca ◽  
Maria Teresa Sbardi
Keyword(s):  
Low Cost ◽  
Inorganic Ions ◽  
Solid Material ◽  
Least Squares Regression ◽  
Biological Interest ◽  
Analyte Content ◽  
Commercial Paper ◽  
Indicator Dye ◽  
The Relationship ◽  
Colorimetric Sensors

We describe disposable and cheap colorimetric devices obtained by fixing classical dyes on the commercial paper sheet known as "Colour Catcher®" (here named under the acronym CC), the product used to prevent color runs in washing machines cycles. These devices can be used as colorimetric sensors for different analytes of environmental and biological interest since the indicator dye, fixed on the solid material, changes its spectral properties (color and hence UV-vis spectrum) upon contact with the analyte. The relationship between the analyte content and the UV-vis spectrum (or RGB values) change of each sensor is provided using a chemometric tool: the Partial Least Squares regression (PLS). Promising results were obtained when applying these sensors to actual samples, so because of their simple preparation with low-cost reagents, they can be effective for application in environmental and food analysis.

scholarly journals Modelling the elastic mechanical properties of bioactive glass-derived scaffolds

2020 ◽  
Vol 6 (1) ◽  
pp. 50-56
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Solid Material ◽  
Poisson's Ratio ◽  
Predictive Capability ◽  
Shear Moduli ◽  
Wide Range ◽  
Constitutive Parameters ◽  
The Relationship

AbstractPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson’s ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson’s ratio is well fitted by a linear equation.

The impact of executives’ perceptions of environmental threats and organizational slack on innovation strategies

2016 ◽  
Vol 7 (2) ◽  
pp. 216-230 ◽  
Author(s):  
Chengyuan Wang ◽  
Biao Luo ◽  
Yong Liu ◽  
Zhengyun Wei
Keyword(s):  
Cognitive Theory ◽  
Environmental Changes ◽  
Ordinary Least Squares ◽  
Organizational Slack ◽  
Least Squares Regression ◽  
Content Type ◽  
Environmental Threats ◽  
Innovation Strategies ◽  
The Impact ◽  
The Relationship

Purpose The paper aims to study the relationship between executives’ perceptions of environmental threats and innovation strategies and investigate the moderating effect of contextual factor (i.e. organizational slack) on such relations. It proposes a dualistic relationship between executives’ perceptions of environmental threats and innovation strategies, in which different perceptions of environmental threats will lead to corresponding innovation strategies, and dyadic organizational slack can promote such processes. Design/methodology/approach The paper is based on a survey with 163 valid questionnaires, which were all completed by executives. Hierarchical ordinary least-squares regression analysis is used to test the hypotheses proposed in this paper. Findings The paper provides empirical insights about that executives tend to choose exploratory innovation when they perceive environmental changes as likely loss threats, yet adopt exploitative innovation when perceiving control-reducing threats. Furthermore, unabsorbed slack (e.g. financial redundancy) positively moderates both relationships, while absorbed slack (e.g. operational redundancy) merely positively influences the relationship between the perception of control-reducing threats and exploitative innovation. Originality/value The paper bridges the gap between organizational innovation and cognitive theory by proposing a dualistic relationship between executives’ perceptions of environmental threats and innovation strategies. The paper further enriches innovation studies by jointly considering both subjective and objective influence factors of innovation and argues that organizational slack can moderate such dualistic relationship.

scholarly journals Retrospectives: The Introduction of the Cobb–Douglas Regression

2012 ◽  
Vol 26 (2) ◽  
pp. 223-236 ◽  
Author(s):  
Jeff Biddle
Keyword(s):  
Time Series Data ◽  
Series Data ◽  
Mathematical Representation ◽  
Least Squares Regression ◽  
Empirical Measures ◽  
Stable Relationship ◽  
Initial Application ◽  
Economic Association ◽  
The Relationship ◽  
Theory Of Production

At the 1927 meetings of the American Economic Association, Paul Douglas presented a paper entitled “A Theory of Production,” which he had coauthored with Charles Cobb. The paper proposed the now familiar Cobb–Douglas function as a mathematical representation of the relationship between capital, labor, and output. The paper's innovation, however, was not the function itself, which had originally been proposed by Knut Wicksell, but the use of the function as the basis of a statistical procedure for estimating the relationship between inputs and output. The paper's least squares regression of the log of the output-to-capital ratio in manufacturing on the log of the labor-to-capital ratio—the first Cobb–Douglas regression—was a realization of Douglas's innovative vision that a stable relationship between empirical measures of inputs and outputs could be discovered through statistical analysis, and that this stable relationship could cast light on important questions of economic theory and policy. This essay provides an account of the introduction of the Cobb–Douglas regression: its roots in Douglas's own work and in trends in economics in the 1920s, its initial application to time series data in the 1927 paper and Douglas's 1934 book The Theory of Wages, and the early reactions of economists to this new empirical tool.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

Audit committee characteristics and the moderating effect of Malaysian code of corporate governance on IPO liquidity

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amal Mohammed Al-Masawa ◽  
Rasidah Mohd-Rashid ◽  
Hamdan Amer Al-Jaifi ◽  
Shaker Dahan Al-Duais
Keyword(s):  
Corporate Governance ◽  
Initial Public Offerings ◽  
Audit Committee ◽  
Ordinary Least Squares ◽  
Moderating Effect ◽  
Least Squares Regression ◽  
Content Type ◽  
Code Of Corporate Governance ◽  
The Impact ◽  
The Relationship

Purpose This study aims to investigate the link between audit committee characteristics and the liquidity of initial public offerings (IPOs) in Malaysia, which is an emerging economy in Southeast Asia. Another purpose of this study is to examine the moderating effect of the revised Malaysian code of corporate governance (MCCG) on the link between audit committee characteristics and IPO liquidity. Design/methodology/approach The final sample consists of 304 Malaysian IPOs listed in 2002–2017. This study uses ordinary least squares regression method to analyse the data. To confirm this study’s findings, a hierarchical or four-stage regression analysis is used to compare the t-values of the main and moderate regression models. Findings The findings show that audit committee characteristics (size and director independence) have a positive and significant relationship with IPO liquidity. Also, the revised MCCG positively moderates the relationship between audit committee characteristics and IPO liquidity. Research limitations/implications This study’s findings indicate that companies with higher audit committee independence have a more effective monitoring mechanism that mitigates information asymmetry, thus reducing adverse selection issues during share trading. Practical implications Policymakers could use the results of this study in developing policies for IPO liquidity improvements. Additionally, the findings are useful for traders and investors in their investment decision-making. For companies, the findings highlight the crucial role of the audit committee as part of the control system that monitors corporate governance. Originality/value To the authors’ knowledge, this work is a pioneering study in the context of a developing country, specifically Malaysia that investigates the impact of audit committee characteristics on IPO liquidity. Previously, the link between corporate governance and IPO liquidity had not been investigated in Malaysia. This study also contributes to the IPO literature by providing empirical evidence regarding the moderating effect of the revised MCCG on the relationship between audit committee characteristics and IPO liquidity.

Kinetostatic backflip strategy for self-recovery of quadruped robots with the selected rotation axis

Robotica ◽  
2021 ◽  
pp. 1-19
Author(s):  
Shengjie Wang ◽  
Kun Wang ◽  
Chunsong Zhang ◽  
Jian S Dai
Keyword(s):  
Optimal Design ◽  
Energy Analysis ◽  
Rotation Axis ◽  
Low Cost ◽  
Minimum Energy ◽  
Design Parameters ◽  
Quadruped Robots ◽  
Design Idea ◽  
The Relationship

Abstract A kinetostatic approach applied to the design of a backflip strategy for quadruped robots is proposed in this paper. Inspired by legged animals and taking the advantage of the leg workspace, this strategy provides an optimal design idea for the low-cost quadruped robots to achieve self-recovery after overturning. Through kinetostatic and energy analysis, a four-stepped backflip strategy based on the selected rotation axis with minimum energy is proposed, with a process of selection, lifting, rotating, and protection. The kinematic factors that affect the backflip are investigated, along with the relationship between the design parameters of the leg and trunk being analyzed. At the end of this paper, the strategy is validated by a simulation and experiments with a prototype called DRbot, demonstrating that the strategy endows the robot a strong self-recovery ability in various terrains.

AN EXPLORATION OF THE RELATIONSHIP BETWEEN THE QUALITY OF PUBLIC GOVERNANCE AND INCOME INEQUALITY: A CASE STUDY OF VIETNAM

2021 ◽  
pp. 1-15
Author(s):  
PHUC VAN PHAN
Keyword(s):  
Income Inequality ◽  
Local Governance ◽  
Low Cost ◽  
Generalized Method Of Moments ◽  
Dynamic Panel Data ◽  
Living Standard ◽  
Public Governance ◽  
The Relationship

Public governance and income inequality relationship is complex and debatable. This paper examines the extent to which the quality of local governance affects inequality in Vietnam spanning the 2006–2016 period. I apply a generalized method of moments (GMM) estimators to a dynamic panel data extracted from the Vietnam’s provincial competitiveness index and the Vietnam household living standard surveys. The findings are that there is a positive inequality — corruption link but no statistically significant correlation coefficient between the overall level of governance and income disparity. The study, therefore, suggests that the Vietnamese Government at all levels should consider both more effective legal practices and economic low-cost solutions to mitigate corruption.

Trilateration approaches for seamless out-/indoor GNSS and Wi-Fi smartphone positioning

2019 ◽  
Vol 13 (1) ◽  
pp. 47-61
Author(s):  
Guenther Retscher ◽  
Jonathan Kleine ◽  
Lisa Whitemore
Keyword(s):  
Inertial Sensors ◽  
Low Cost ◽  
Ground Truth ◽  
Mobile User ◽  
Location Based Services ◽  
Raspberry Pi ◽  
Indoor Environments ◽  
Point Location ◽  
Point Determination ◽  
The Relationship

Abstract More and more sensors and receivers are found nowadays in smartphones which can enable and improve positioning for Location-based Services and other navigation applications. Apart from inertial sensors, such as accelerometers, gyroscope and magnetometer, receivers for Wireless Fidelity (Wi-Fi) and GNSS signals can be employed for positioning of a mobile user. In this study, three trilateration methods for Wi-Fi positioning are investigated whereby the influence of the derivation of the relationship between the received signal strength (RSS) and the range to an Access Points (AP) are analyzed. The first approach is a straightforward resection for point determination and the second is based on the calculation of the center of gravity in a triangle of APs while weighting the received RSS. In the third method a differential approach is employed where as in Differential GNSS (DGNSS) corrections are derived and applied to the raw RSS measurements. In this Differential Wi-Fi (DWi-Fi) method, reference stations realized by low-cost Raspberry Pi units are used to model temporal RSS variations. In the experiments in this study two different indoor environments are used, one in a laboratory and the second in the entrance of an office building. The results of the second and third approach show position deviations from the ground truth of around 2 m in dependence of the geometrical point location. Furthermore, the transition between GNSS positioning outdoors and Wi-Fi localization indoors in the entrance area of the building is studied.

scholarly journals Low-Cost Polyethylene Terephthalate Fluidic Sensor for Ultrahigh Accuracy Measurement of Liquid Concentration Variation

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7410
Author(s):  
Ruey-Ching Twu ◽  
Kai-Hsuan Li ◽  
Bo-Lin Lin
Keyword(s):  
Polyethylene Terephthalate ◽  
Low Cost ◽  
Phase Variation ◽  
Liquid Solution ◽  
Concentration Variation ◽  
Accuracy Measurement ◽  
Common Path ◽  
The Relationship ◽  
Index Unit ◽  
Measured Phase

A low-cost polyethylene terephthalate fluidic sensor (PET-FS) is demonstrated for the concentration variation measurement on fluidic solutions. The PET-FS consisted of a triangular fluidic container attached with a birefringent PET thin layer. The PET-FS was injected with the test liquid solution that was placed in a common path polarization interferometer by utilizing a heterodyne scheme. The measured phase variation of probe light was used to obtain the information regarding the concentration change in the fluidic liquids. The sensor was experimentally tested using different concentrations of sodium chloride solution showing a sensitivity of 3.52 ×104 deg./refractive index unit (RIU) and a detection resolution of 6.25 × 10−6 RIU. The estimated sensitivity and detection resolutions were 5.62 × 104 (deg./RIU) and 6.94 × 10−6 RIU, respectively, for the hydrochloric acid. The relationship between the measured phase and the concentration is linear with an R-squared value reaching above 0.995.

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