Search results for " Modeling"

Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems

2011

The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Rea…

Measuring perceived community support: Factorial structure, longitudinal invariance, and predictive validity of the PCSQ (perceived community support…

2007

Social support from intimate and confiding relationships has received a great deal of attention; however, the study of the community as a relevant source of support has been comparatively lacking. In this article, we present a multidimensional measure of community support (Perceived Community Support Questionnaire, PCSQ). Through exploratory and confirmatory factor analyses on data from three samples of adult population (two-wave panel: sample 1, N = 1009 and sample 2, N = 780; and an independent sample 3, N = 440), results show that community integration, community participation, and use of community organizations are reliable indicators of the underlying construct of perceived community s…

Trait self-control and self-discipline : Structure, validity, and invariance across national groups

2021

The aim of the present study was to test the validity of the Brief Self-Control Scale (BSCS; Tangney, Baumeister and Boone 2004) including its dimensional structure based on competing one- and two-factor models, discriminant validity from the conceptually-related self-discipline construct, invariance across multiple samples from different national groups, and predictive validity with respect to health-related behaviors. Samples of undergraduate students (total N = 1282) from four national groups completed the brief self-control scale, the self-discipline scale from the NEO-PI-R, and self-report measures of binge drinking, exercise, and healthy eating. Confirmatory factor analytic models sup…

Aslian linguistic prehistory: A case study in computational phylogenetics

2011

This paper analyzes newly collected lexical data from 26 languages of the Aslian subgroup of the Austroasiatic language family using computational phylogenetic methods. We show the most likely topology of the Aslian family tree, discuss rooting and external relationships to other Austroasiatic languages, and investigate differences in the rates of diversification of different branches. Evidence is given supporting the classification of Jah Hut as a fourth top level subgroup of the family. The phylogenetic positions of known geographic and linguistic outlier languages are clarified, and the relationships of the little studied Aslian languages of Southern Thailand to the rest of the family ar…

Digital Technologies for Cultural Heritage Preservation. A case study.

2014

Within the study and knowledge of Cultural Heritage, the Virtual Restoration represents an innovative technical-scientific sector that involves the use of Information and Communications Technologies (ICT) within traditional and well-established methodologies. The study illustrates a practical experience carried out on a cycle of sculptural works made in stucco that currently shows a number of fragmentary and disjointed parts. In this research a methodological approach is described, whose aim was to build a 3D model and formulate an hypothesis of virtual recomposition of the fragments. In addition, it provided useful geometrical-formal support tools both for the physical-material restoration…

Numerical prediction of turbulent flow and heat transfer in helically coiled pipes

2010

Abstract Computational results were obtained for turbulent flow and heat transfer in curved pipes, representative of helically coiled heat exchangers. Following a grid refinement study, grid independent predictions from alternative turbulence models ( k – ɛ , SST k – ω and RSM– ω ) were compared with DNS results and experimental pressure drop and heat transfer data. Using the SST k – ω and RSM– ω models, pressure drop results were in excellent agreement with literature data and the Ito correlation. For heat transfer, the literature is not comparably complete or accurate, but a satisfactory agreement was obtained in the range of available data. Unsatisfactory results, both for pressure drop …

CFD Modelling of the Demister in the Multi Stage Flash Desalination plant

2011

Abstract Demisters are used to remove entrained brine droplets from flashed off vapor within the flashing stages of the multi stage flash desalination process (MSF). This is necessary to prevent accumulation of brine droplets on the outside surface of the condenser tubes and contamination of the desalinated water. The aim of this work is to design a new demister with lower pressure drop and unaffected separation efficiency which can be later installed in the flashing stages of the MSF plant and causes reduction in the required heat transfer area. In this work the demister performance is predicted as a function of design (wire diameter), and operating parameters (stage temperature). This obj…

Multivariate Methods and Molecular Modeling Techniques in the study of Antitumor Agents

2008

An Importance-Performance Matrix Analysis of the Factors Influencing US Tourists to Use Airbnb

2019

After 10 years of Airbnb and its significant growth, this research is conducted to identify which factors really matter to Airbnb users today. It provides an integrated approach, since it aggregates factors that other studies have considered separately. With a sample of 101 US respondents, the partial least squares structural equation modelling results evidence that the only factors that influence future intentions to use Airbnb are its unique and varied accommodations and satisfaction. Enjoyment was also found to have a positive effect on Satisfaction. The study further investigates these factors with an Importance Performance map, providing guidance for the prioritization of managerial ac…

Soil Science Challenges in a New Era: A Transdisciplinary Overview of Relevant Topics

2020

Transdisciplinary approaches that provide holistic views are essential to properly understand soil processes and the importance of soil to society and will be crucial in the future to integrate distinct disciplines into soil studies. A myriad of challenges faces soil science at the beginning of the 2020s. The main aim of this overview is to assess past achievements and current challenges regarding soil threats such as ero-sion and soil contamination related to different United Nations sustainable development goals (SDGs) including (1) sustainable food production, (2) ensure healthy lives and reduce environmental risks (SDG3), (3) ensure water availability (SDG6), and (4) enhanced soil carbo…