Project Ecosystem Competency Model

AbstractThis study proposes a conceptual framework of Project Ecosystem Competency Model that could contribute to the creation of sustainable performance in engineering organizations and industries as well as enhancing the value of project stakeholders to contribute to project sustainability.Within the engineering organizations, working processes are evolving from operational-oriented processes, which are repetitive and sustainable, to project-oriented processes, which can be defined as temporary and unique. In addition, organizational structures are changing from functional structures to project-driven structures. For example, engineering projects are becoming influential to industrial and organizational sustainability because of its performance of special features and requirements of the projects. However, engineering projects are not easily sustainable because they are only evaluated by one criterion whether the project has succeeded or failed.For many organizations or industries, more than one project is being executed simultaneously, and these multi-project environments can affect the sustainability of the organizations or industries. This study proposes a Project Ecosystem Competency Model to show how ecosystem impacts project lifecycle and understand mutual and reciprocal relationship for successful management of multiple projects. Project Ecosystem Competency Model consists of three aspects: design and maturity of the project ecosystem; project success factors and performance index; and the competency of engineering project management organization that contributes to the maturity of the project ecosystem

Optimization of gear teeth in the wind turbine drive train with gear contact’s uncertainty using the reliability-based design optimization

Although gear teeth give lots of advantages, there is a high possibility of failure in gear teeth in each gear stage in the drive train system. In this research, the authors developed proper gear teeth using the basic theorem of gear failure and reliability-based design optimization. A design variable characterized by a probability distribution was applied to the static stress analysis model and the dynamics analysis model to determine an objective function and constraint equations and to solve the reliability-based design optimization. For the optimization, the authors simulated the torsional drive train system which includes rotational coordinates. First, the authors established a static stress analysis model which gives information about endurance limit and bending strength. By expressing gear mesh stiffness in terms of the Fourier series, the equations of motion including the gear mesh models and kinematical relations in the drive train system were acquired in the form of the Lagrange equations and constraint equations. For the numerical analysis, the Newmark Beta method was used to get dynamic responses including gear mesh contact forces. From the results such as the gear mesh contact force, the authors calculated the probability of failure, arranged each probability and gear teeth, and proposed a reasonable and economic design of gear teeth

VIBRATIONAL CASE STUDY FOR THE MOLD OSCILLATOR WITH HYDRAULIC SERVO SYSTEM

We have conducted sensitivity analysis to investigate the two-hydraulic-servo system for the mold oscillator. By modelling mathematical models for operating fluid flow to control a hydraulic cylinder, we changed design parameters and environment conditions including friction, additional spring stiffness and fluid leakage. From the one-hydraulic servo system to the two-hydraulic cylinder, modal analysis was conducted to figure out dynamic characteristics of the real system. Especially, we categorized important natural mode shape. When the system was excited into the natural frequency, the 1st mechanical natural frequency could cause a pressure gain by reducing internal pressure of a hydraulic cylinder, but other natural frequencies were critically dangerous by generating imbalance, over-vibration and distortion. By comparing the results to the experimental data, we could find a dramatic pressure drop near 3 Hz oscillation when the system has the 1st mechanical natural frequency 2.499 Hz. Also, the system has the imbalance near 6 Hz oscillation when the system has 2nd mechanical natural frequency 5.446 Hz. Based on these fact, we have suggested some tips to oscillate a mold efficiently and safely

VIBRATIONAL CASE STUDY FOR THE MOLD OSCILLATOR WITH HYDRAULIC SERVO SYSTEM

We have conducted sensitivity analysis to investigate the two-hydraulic-servo system for the mold oscillator. By modelling mathematical models for operating fluid flow to control a hydraulic cylinder, we changed design parameters and environment conditions including friction, additional spring stiffness and fluid leakage. From the one-hydraulic servo system to the two-hydraulic cylinder, modal analysis was conducted to figure out dynamic characteristics of the real system. Especially, we categorized important natural mode shape. When the system was excited into the natural frequency, the 1st mechanical natural frequency could cause a pressure gain by reducing internal pressure of a hydraulic cylinder, but other natural frequencies were critically dangerous by generating imbalance, over-vibration and distortion. By comparing the results to the experimental data, we could find a dramatic pressure drop near 3 Hz oscillation when the system has the 1st mechanical natural frequency 2.499 Hz. Also, the system has the imbalance near 6 Hz oscillation when the system has 2nd mechanical natural frequency 5.446 Hz. Based on these fact, we have suggested some tips to oscillate a mold efficiently and safely

Dietary calcium intake and the risk of colorectal cancer: a case control study

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background High intake of dietary calcium has been thought to be a protective factor against colorectal cancer. To explore the dose-response relationship in the associations between dietary calcium intake and colorectal cancer risk by cancer location, we conducted a case-control study among Korean population, whose dietary calcium intake levels are relatively low. Methods The colorectal cancer cases and controls were recruited from the National Cancer Center in Korea between August 2010 and August 2013. Information on dietary calcium intake was assessed using a semi-quantitative food frequency questionnaire and locations of the colorectal cancers were classified as proximal colon cancer, distal colon cancer, and rectal cancer. Binary and polytomous logistic regression models were used to evaluate the association between dietary calcium intake and risk of colorectal cancer. Results A total of 922 colorectal cancer cases and 2766 controls were included in the final analysis. Compared with the lowest calcium intake quartile, the highest quartile group showed a significantly reduced risk of colorectal cancer in both men and women. (Odds ratio (OR): 0.16, 95 % confidence interval (CI): 0.11–0.24 for men; OR: 0.16, 95 % CI: 0.09–0.29 for women). Among the highest calcium intake groups, decrease in cancer risk was observed across all sub-sites of colorectum in both men and women. Conclusion In conclusion, calcium consumption was inversely related to colorectal cancer risk in Korean population where national average calcium intake level is relatively lower than Western countries. A decreased risk of colorectal cancer by calcium intake was observed in all sub-sites in men and women

Single atom and defect engineering of CuO for efficient electrochemical reduction of CO 2 to C 2 H 4

Electrochemical CO2 transformation to high‐value ethylene (C2H4) at high currents and efficiencies is desired and yet remains a grand challenge. We show for the first time that coupling single Sb atoms and oxygen vacancies of CuO enable synergistic electrocatalytic reduction of CO2 to C2H4 at low overpotentials. Highly dispersed Sb atoms occupying metal substitutional sites of CuO are synthesized under mild conditions. The overall CO2 reduction faradaic efficiency (FE) reaches 89.3 ± 1.1% with an FE toward C2H4 exceeding 58.4% at a high‐current density of 500 mA/cm2. Addition of the p‐block metal is found to induce transformation of CuO from flakes to nanoribbons rich in nanoholes and oxygen vacancies, greatly enhancing CO2 adsorption and activation while suppressing hydrogen evolution. Further density functional theory calculations with in situ X‐ray diffraction reveal that combining Sb sites and oxygen vacancies prominently lessen the dimerization energy of adsorbed CO intermediate, thus boosting the conversion of CO2 to produce C2H4. This study provides a new perspective for promoting selective C–C coupling for electrochemical CO2 reduction

Therapeutic effect of ascorbic acid on dapsone-induced methemoglobinemia in rats

Objective Dapsone (diaminodiphenyl sulfone, DDS) is currently used to treat leprosy, malaria, dermatitis herpetiformis, and other diseases. It is also used to treat pneumocystis pneumonia and Toxoplasma gondii infection in HIV-positive patients. The most common adverse effect of DDS is methemoglobinemia from oxidative stress. Ascorbic acid is an antioxidant and reducing agent that scavenges the free radicals produced by oxidative stress. The present study aimed to investigate the effect of ascorbic acid in the treatment of DDS induced methemoglobinemia. Methods Male Sprague-Dawley rats were divided into three groups: an ascorbic acid group, a methylene blue (MB) group, and a control group. After DDS (40 mg/kg) treatment via oral gavage, ascorbic acid (15 mg/kg), MB (1 mg/kg), or normal saline were administered via tail vein injection. Depending on the duration of the DDS treatment, blood methemoglobin levels, as well as the nitric oxide levels and catalase activity, were measured at 60, 120, or 180 minutes after DDS administration. Results Methemoglobin concentrations in the ascorbic acid and MB groups were significantly lower compared to those in the control group across multiple time points. The plasma nitric oxide levels and catalase activity were not different among the groups or time points. Conclusion Intravenous ascorbic acid administration is effective in treating DDS-induced methemoglobinemia in a murine model