4653 research outputs found
Sort by
How does exercise affect energy metabolism? An in silico approach for cardiac muscle
No full textWe explored an in silico model of muscle energy metabolism and demonstrated its theoretical plausibility. Results indicate that energy metabolism triggered by activation can capture the muscle condition, rest, or exercise, and can respond accordingly adjusting the rates of their respiration and energy utilization for efficient use of the nutrients. Our study demonstrated during exercise higher respiratory activity causes a substantial increase in exergy release with an increase in exergy destruction, and entropy generation rate. The thermodynamic analysis showed that at the resting state when the exergy destruction rate was 0.66 W/kg and the respiratory metabolism energetic efficiency was 36% and exergetic efficiency was 32% || whereas, when the exergy destroyed was 1.24 W/kg, the energetic efficiency was 58% and exergetic efficiency was 50% during exercise. The efficiency results suggest the ability of the system to regulate itself in response to higher work demand and become more efficient in terms of converting energy coming from nutrients to useable energy when the circulating medium has sufficient energy precursor.Multidisciplinary Science
Data-driven decision making for modelling covid-19 and its implications: A cross-country study
No full textGrounded in big data analytics capabilities, this study aims to model the COVID-19 spread globally by considering various factors such as demographic, cultural, health system, economic, technological, and policy-based. Classified values on each country's case, death, and recovery numbers (per 1000,000 population) were used to represent COVID-19 spread. Data sets also included 29 input variables for the corresponding six factors, containing data from 159 countries. The proposed model used a Multilayer Perceptron algorithm. The results show that each of the pre-mentioned factors significantly affects disease spread. Urban population, median age, life expectancy, numbers of medical doctors and nursing personnel, current health expenditure as a % of GDP, international health regulations capacity score, continent, literacy rate, governmental response stringency index, testing policy, internet usage %, human development index and GDP per capita were identified as significant. Taking early measures and adopting open public testing policies were recommended to policymakers in fighting pandemic diseases since the created scenarios on policy-based factors revealed their importance.Business || Regional & Urban Plannin
Self-powered photodetector array based on individual graphene electrode and silicon-on-insulator integration
No full textOne of the key limitations for the device performance of the silicon (Si) based photodetector arrays is the optical crosstalk effect encountered between photoactive elements as well. The scope of this work is to reduce optical crosstalk and thus increasing the device performances with graphene and Si integration. This paper presents the design, fabrication process, and performance evaluation of self-powered individual Graphene/Silicon on Insu-lator (GSOI) based Schottky barrier photodiode array (PDA) devices. A 4-element GSOI Schottky barrier PDA with separate graphene electrodes is fabricated to examine possible optical crosstalk encountered between each diode in the array structure. Here, monolayer graphene is utilized as hole collecting separate electrode on individually arrayed n-type Si on SOI substrate by photolithography technique. Each diode in the array exhibited a clear rectifying Schottky character. Photoresponse characterizations revealed that all diodes had excellent device performance even in self-powered mode in terms of an Ilight/Idark ratio up to 104, a responsivity of-0.12 A/W, a specific detectivity of around 1.6 x 1012 Jones, and a response speed of-1.32 & mu;s at 660 nm wavelength. As revealed by optical crosstalk measurement, the device with pixel pitch of 1.5 mm had a total crosstalk of about 0.10% (-60 dB) per array. These results showed that the optical crosstalk between neighboring n-Si elements can be greatly minimized when graphene is used as separated electrode on arrayed Si on SOI substrate. Our study is expected give an insight into the performance characteristics of GSOI PDA devices which have great potential to be used in many technological applications such as multi-wavelength light measurement, level metering, high-speed photometry and position/motion detection.Engineering, Electrical & Electronic || Instruments & Instrumentatio
Avoidable thermodynamic inefficiencies evaluation of a sewage water source heat pump system
No full textThe performance of a sewage water source heat pump system is assessed through conventional/enhanced exergy-based methods in this present study. The experimental data used in the analyses are based the cooling mode. According to the conventional-based results, the condenser has the lowest exergy efficiency. Beside this, the enhanced exergy-based analysis results show the sewage water heat exchanger should be considered as the most significant component as it has the highest avoidable exergy destruction rate in the whole system and takes the improvement priority. Based on the enhanced exergy analysis, 56% of the total exergy destruction belongs to the avoidable part.Thermodynamics || Energy & Fuel
Cost and performance comparison of tier-captive SBS/RS with a novel AVS/RS/ML
No full textThis paper introduces a novel autonomous vehicle-based storage and retrieval system that utilizes movable lifts (AVS/RS/ML), proposed as an alternative to the tier-captive shuttle-based storage and retrieval system (SBS/RS). The newly proposed system aims to provide an affordable solution with highly utilised AGVs, that can also perform operations out of warehouse. The performance of this novel system is compared with the equivalent tier-captive SBS/RS warehouse design, where each shuttle is dedicated in a specific tier in that design. The comparison is based on the initial system investments costs, throughput rates, and average utilisation of lifts/MLs in the system. Collision prevention rules are also applied to AVS/RS/ML, and its performance is tested through simulation. The results show that the tier-captive SBS/SR system becomes cost-efficient under high throughput rate requirements, while the AVS/RS/ML technology is preferred for relatively moderate and low process rate requirements. The unit-cost per month performance metric of AVS/RS/ML is less sensitive to an increase in number of tiers in the system, compared to the tier-captive SBS/RS case, indicating that AVS/RS/ML may be promising for high-tier warehouse system designs.Engineering, Industrial || Engineering, Manufacturing || Operations Research & Management Scienc
Drivers for circular economy development: making businesses more environmentally friendly
No full textStakeholders have been pressuring companies to develop more environmentally friendly strategic and operational solutions. In this sense, companies are seeking alternatives that reduce the negative impacts of organizational activities, Circular Economy (CE) is one of the solutions with the greatest potential for success. Thus, the goal of this paper is to provide drivers for organizations' transition from a linear to a CE. For this reason, content analysis was used as the scientific method, for being appropriate for the interpretation of qualitative data and the identification, clustering, and systematization of themes in a given field of knowledge. In the case of this work, a set of 30 articles with information related to the implementation and development of CE were analyzed, allowing the identification of 19 key elements of CE. These key elements were then grouped and systematized into four drivers: decision-making || capacity and training || sustainable practices || and green supply chain. Scientifically, this work contributes to the improvement and increase of the block of knowledge about the CE, because the drivers can be used to advance the state of the art and as a starting point for the development of new research. In an applied way, the drivers proposed in this article provide a range of actions for managers to make their companies greener and improve their organizational performance, thus contributing environmentally and socially to the planet.Environmental Science
Power function and binomial series on T(q,h)
No full textThis article is devoted to present (q , h) -analogue of power function which satisfies additivity and derivative properties similar to the ordinary power function. In the light of nabla (q , h) -power function, we present (q , h)-analogue of binomial series and conclude that such power function is (q , h)-analytic. We prove the analyticity by showing that both the power function and its absolutely convergent Taylor series solve the same IVP. Finally, we present the reductions of (q , h)-binomial series to classical binomial series, Gauss' binomial and Newton's binomial formulas.Engineering, Multidisciplinary || Mathematics, Interdisciplinary Application
A collaborative numerical simulation-soft computing approach for earth dams first impoundment modeling
No full textUncertainty quantification plays a crucial role in the design, monitoring, and risk assessment of earth dams. To reduce the computational burden, we employ a combination of finite difference method and soft computing techniques to investigate material uncertainties in earth dams during the initial impoundment stage. The findings of sensitivity analysis with the Tornado diagram indicate that key material properties such as dry density, elasticity modulus, friction angle, and Poisson's ratio significantly influence the displacements and stress analysis. In our study, we explore four variants of extreme learning machines (ELMs): the standalone ELM, hybridized versions with the improved grey wolf optimizer algorithm, ant colony optimization for continuous domains, and artificial bee colony. These methods are assessed across various training sizes to predict multiple parameters, including horizontal and vertical displacements, stresses, and the factor of safety (FoS). The hybridized ELM with the improved grey wolf optimizer algorithm emerges as the superior choice for most of the response variables. A minimum of 200 numerical simulations is required to establish a stable and accurate meta-model with an average prediction error of less than 3% for responses and the FoS.Computer Science, Interdisciplinary Applications || Engineering, Geological || Geosciences, Multidisciplinar
Barriers to Cement Industry Towards Circular Economy
No full textCement, as the main component of concrete, is a crucial industrial product for economic development and civilization. Nevertheless, its production is highly energy-intensive, environmentally polluting, and a source of extreme CO2 emissions. For success in the transition to the circular economy and accelerating sustainable manufacturing in the cement industry, understanding and addressing the main barriers are essential. Using the above point of view, this study intends to address the challenges and barriers of the cement industry in the transition to a circular economy, define the causal relationships between these barriers, and determine the necessary practical implications to overcome the barriers. Systematic literature review and focus group study results enable a holistic model that integrates research results and business practical criteria. The DEMATEL method is used for the clarification of causal relations between factors. A total of 18 barriers in 6 clusters have been revealed to be used for managerial implications to speed up the transition to CE applications in the cement business. Out of 18 barriers, 6 were effect groups, which were the outcomes due to the remaining 12 causing barriers. The top three cause factors are an unstable waste market, lack of management competencies, and unstable macroeconomic conditions, while the leading three effect factors are revealed as giving priority to other issues, insufficient organisational structures, and deviations in product quality. Although there are many studies on CE in cement, they are concentrated on technical and laboratory studies enabling the use of different alternative materials as inputs to the cement process. Studying and revealing the barriers holding back the cement sector in the transition to CE is this study's core contribution, making it novel and unique.Engineering, Multidisciplinary || Operations Research & Management Science || Mathematics, Applie
DISENTANGLING THE INNOVATION ORIENTATION, INTELLECTUAL CAPITAL, AND DYNAMIC INNOVATION CAPABILITY RELATIONSHIPS IN EMERGING ECONOMY START-UPS
No full textPurpose: Based on the Dynamic Capabilities View (DCV) and Knowledge-based View (KBV), this study investigates the relationships between intellectual capital (IC) resources and dynamic innovation capabilities in the context of new ventures.Design/methodology/approach: Data for the study is collected from 311 start-up firms in Turkey and is analysed via Structural Equation Modelling.Findings: The results indicate that the effects of human capital and social capital on dynamic innovation capability are fully mediated by innovation orientation (IO). Besides, dynamic innovation capability is found to be strongly associated with innovation performance.Practical implications: In the study, IO is suggested as a useful mechanism for encouraging the deployment of an innovation focus in all functions of a firm for attaining long-term sustained competitiveness. Thereby, the findings are expected to present important implications for start-up founders and policy-makers, by highlighting the importance of knowledge management and investing in human and social capital resources for generating the capability to innovate.Originality/value: The most significant contribution of the study is the development of a model suggesting IO as a mediating variable between the IC resources and dynamic innovation capability relationship in the context of start-up firms. Furthermore, the findings indicate a positive and significant association between the dynamic innovation capability and innovation performance in these economic units.Managemen