scholarly journals Towards a Solid Particle Hydrodynamic (SPH)-Based Solids Transport Model Applied to Ultra-Low Water Usage Sanitation in Developing Countries

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 441
Author(s):  
Michael Gormley ◽  
Sophie MacLeod
Keyword(s):  
Urban Areas ◽  
Transport Model ◽  
Low Cost ◽  
Fluid Velocity ◽  
Water Usage ◽  
Middle Income ◽  
Solids Transport ◽  
Sph Model ◽  
Solid Transport ◽  
And Performance

Distribution of toilet facilities and low-cost small-bore simplified sewerage systems (SS) in peri-urban areas provide opportunities to improve public health, provide safely managed sanitation, and protect the environment in low-to-middle income countries. Smoothed particle hydrodynamics (SPH) offers opportunities for optimisation of ultra-low water usage systems, but not without computational challenges. Results from SPH modelling of low cost, low water usage sanitary appliances were compared to a validated 1D finite difference model (DRAINET) for evaluation and calibration. An evaluation of system performance linked solid transport capabilities to physical geometries. The SPH model was developed for a pour-flush toilet pan connected to a 100 mm diameter pipe. The scheme utilized a free surface turbulent model to evaluate solid (faecal) transport efficacy. Performance was greatly influenced by the artificial viscosity factor, ViscoBoundFactor, within SPH, relating to the interaction of fluid and fluid particles and fluid and boundary particles. Results indicate that an increase in this factor leads to a reduction in fluid velocity with an attendant reduction in solid transportation distance, leading to inaccuracies. Other issues such as the use of density and mass in the definition of solid characteristics made it less predictable than the established 1D model for predicting solid transport. Overall, SPH was found to be useful for characterising the geometry of the pour flush pan but not for whole system assessment. A hybrid method is thus recommended whereby the design and performance characteristics for the input stage can be modelling in SPH but the whole system pipe network evaluation is better suited to the 1D DRAINET model.

scholarly journals A study on visual preference for social stimuli in typical Ecuadorian preschoolers as a contribution to the identification of autism risk factors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paulina Buffle ◽  
Thalia Cavadini ◽  
Andres Posada ◽  
Edouard Gentaz
Keyword(s):  
Risk Factors ◽  
Eye Tracking ◽  
Urban Areas ◽  
Moving Objects ◽  
Low Cost ◽  
Autism Spectrum ◽  
Visual Preference ◽  
Middle Income ◽  
Rural And Urban Areas ◽  
Tracking Device

AbstractThe goal of this study was to examine the visual preference towards socially salient stimuli, using a low-cost eye-tracking device in a group of typically developing (TD) Ecuadorian preschoolers aged 11 to 60 months, from rural and urban areas, and from families with low to high socioeconomic status (SES). Series of original stimuli inspired by those used in Western experiments on the early detection of Autism Spectrum Disorder (ASD) were proposed in two eye-tracking tasks. Two types of movements (human vs. object) were presented in task 1, and dynamic speaking faces in task 2. Parental perceptions of the adaptability of the low-cost eye-tracking device used here were also investigated through a questionnaire. The analyses of mean fixation times showed a visual preference for human movements compared to moving objects whatever age, residency location or SES. In task 2, visual preference for the mouth’s area compared to the eyes’ area was observed in specific conditions, modulated by residency location and SES but not by age. The analyses of the parental perception indicated that the eye-tracking technique is well accepted. The findings suggest that these stimuli, along with the experimental procedure and low-cost eye-tracking device used in the present study may be a relevant tool that can be used in clinical settings as a contribution to the early identification of at-risk factors of ASD in low- and middle-income contexts.

scholarly journals The Outdoor Dust Information Node (ODIN) – development and performance assessment of a low cost ambient dust sensor

2015 ◽  
Vol 8 (7) ◽  
pp. 7511-7533 ◽  
Author(s):  
G. Olivares ◽  
S. Edwards
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Low Cost ◽  
Field Tests ◽  
Significant Challenge ◽  
Air Quality Measurements ◽  
Spatial Coverage ◽  
Baseline Response ◽  
And Performance ◽  
Outdoor Dust

Abstract. The large gradients in air quality expected in urban areas present a significant challenge to standard measurement technologies. Small, low-cost devices have been developing rapidly in recent years and have the potential to improve the spatial coverage of traditional air quality measurements. Here we present the first version of the Outdoor Dust Information Node (ODIN) as well as the results of the first real-world measurements. The lab tests indicate that the Sharp dust sensor used in the ODIN presents a stable baseline response only slightly affected by ambient temperature. The field tests indicate that ODIN data can be used to estimate hourly and daily PM2.5 concentrations after appropriate temperature and baseline corrections are applied. The ODIN seems suitable for campaign deployments complementing more traditional measurements.

scholarly journals Estimate of Secondary NO2 Levels at Two Urban Traffic Sites Using Observations and Modelling

2020 ◽  
Vol 12 (19) ◽  
pp. 7897 ◽  
Author(s):  
Grazia Ghermandi ◽  
Sara Fabbi ◽  
Giorgio Veratti ◽  
Alessandro Bigi ◽  
Sergio Teggi
Keyword(s):  
Urban Areas ◽  
Transport Model ◽  
Simulation Models ◽  
Particle Dispersion ◽  
Reggio Emilia ◽  
Urban Traffic ◽  
Chemical Transport Model ◽  
Urban Background ◽  
Regulatory Limits ◽  
And Performance

Assessing secondary and primary NO2 in urban areas is important to support carefully designed environmental policies, particularly in areas with recurrent exceedance of NO2 regulatory limits. The share of secondary NO2 was preliminary estimated in intense traffic areas of Modena and Reggio Emilia (Northern Italy) by the combined analysis of regulatory air quality observations at urban traffic and urban background conditions. In addition simulations performed by the Lagrangian particle dispersion models Micro SWIFT SPRAY and the chemical transport model WRF-Chem were performed. The former was applied on the urban area representative of traffic conditions for both cities, in winter. The latter was applied twice in Modena, both with and without urban traffic emissions. Results suggest a large amount of secondary NO2 mainly at the Modena traffic site, and a better representativity of background conditions of the corresponding urban station in Reggio Emilia. NOx levels simulated by WRF-Chem show good results at Modena urban background and performance in line with reference benchmark values in reproducing observed NO2 and NOx concentrations at rural background sites, although a non-negligible bias in simulated urban NO2 remained. Overall the simulation models suggest that contribution to atmospheric NOx by domestic heating or industrial combustion emissions are not as relevant compared to traffic, consistently with the local emission inventory.

scholarly journals Construction and Performance Testing of a Fast-Assembly COVID-19 (FALCON) Emergency Ventilator in a Model of Normal and Low-Pulmonary Compliance Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Luke A. White ◽  
Ryan P. Mackay ◽  
Giovanni F. Solitro ◽  
Steven A. Conrad ◽  
J. Steven Alexander
Keyword(s):  
Low Cost ◽  
Healthcare Providers ◽  
Performance Testing ◽  
Plug And Play ◽  
Middle Income ◽  
Test Conditions ◽  
Do It Yourself ◽  
Identical Test ◽  
And Performance ◽  
Flow Waveforms

IntroductionThe COVID-19 pandemic has revealed an immense, unmet and international need for available ventilators. Both clinical and engineering groups around the globe have responded through the development of “homemade” or do-it-yourself (DIY) ventilators. Several designs have been prototyped, tested, and shared over the internet. However, many open source DIY ventilators require extensive familiarity with microcontroller programming and electronics assembly, which many healthcare providers may lack. In light of this, we designed and bench tested a low-cost, pressure-controlled mechanical ventilator that is “plug and play” by design, where no end-user microcontroller programming is required. This Fast-AssembLy COVID-Nineteen (FALCON) emergency prototype ventilator can be rapidly assembled and could be readily modified and improved upon to potentially provide a ventilatory option when no other is present, especially in low- and middle-income countries.HypothesisWe anticipated that a minimal component prototype ventilator could be easily assembled that could reproduce pressure/flow waveforms and tidal volumes similar to a hospital grade ventilator (Engström CarestationTM).Materials and MethodsWe benched-tested our prototype ventilator using an artificial test lung under 36 test conditions with varying respiratory rates, peak inspiratory pressures (PIP), positive end expiratory pressures (PEEP), and artificial lung compliances. Pressure and flow waveforms were recorded, and tidal volumes calculated with prototype ventilator performance compared to a hospital-grade ventilator (Engström CarestationTM) under identical test conditions.ResultsPressure and flow waveforms produced by the prototype ventilator were highly similar to the CarestationTM. The ventilator generated consistent PIP/PEEP, with tidal volume ranges similar to the CarestationTM. The FALCON prototype was tested continuously for a 5-day period without failure or significant changes in delivered PIP/PEEP.ConclusionThe FALCON prototype ventilator is an inexpensive and easily-assembled “plug and play” emergency ventilator design. The FALCON ventilator is currently a non-certified prototype that, following further appropriate validation and testing, might eventually be used as a life-saving emergency device in extraordinary circumstances when more sophisticated forms of ventilation are unavailable.

Tenants' Satisfaction in High Residential Building

2020 ◽  
Vol 17 (1) ◽  
pp. 41
Author(s):  
UMMU SHOLEHAH MOHD NOR
Keyword(s):  
Urban Areas ◽  
Residential Buildings ◽  
Low Cost ◽  
Residential Building ◽  
Real Estate Market ◽  
The Real Estate ◽  
Level Of Satisfaction ◽  
Considerable Impact ◽  
Residential Living ◽  
Medium Cost

High residential living in Malaysia has not been widely given a significant emphasises in literature despite its increasing scale and significance in the real estate market. The significance of high rise is mainly due the increasing rate of migration from rural to urban. It is estimated a total of 77.2 percent of the Malaysian population lived in urban areas in 2020. Approximately, 30 percent of this urban population lives in strata housing. These percentages are predicted to continue to increase in the future. The emergence of high residential building has been argued as confronting various problems which has considerable impact on this life style. Satisfaction is an important outcome of living in one’s dwelling, although it is not the only consideration. High residential building in Malaysia encountered numerous problems in term of management aspects, legislation aspects, and residents’ satisfaction. The purpose of this paper is to investigate the tenants’ satisfaction living in high residential buildings in Klang Valley. The questionnaires survey is conducted amongst 276 tenants at low cost and medium cost HRB using random sampling in HRB located at areas under jurisdiction Dewan Bandaraya Kuala Lumpur (DBKL), Majlis Bandaraya Subang Jaya (MBSJ), Majlis Bandaraya Shah Alam (MBSA), Majlis Bandaraya Subang Jaya (MBSJ), Majlis Perbandaran Selayang (MPS) and Majlis Perbandaran Ampang Jaya (MPAJ). The result from this study shows that tenant in medium cost residential building are more satisfied in term of facilities and management as compared to tenants in low cost residential building. Tenants also not disclosed to the existing act and procedure related to high residential building. In conclusion, this study suggested the Local Authority to emphasise the role of tenant. These recommendation hopefully will increase the level of satisfaction amongst the residents in HRB.

A detailed contaminant transport model for facility hazard assessment in urban areas

1999 ◽  
Author(s):  
Bohdan Cybyk ◽  
Jay Boris ◽  
Theodore Young, Jr. ◽  
Charles Lind ◽  
Alexandra Landsberg
Keyword(s):  
Contaminant Transport ◽  
Hazard Assessment ◽  
Urban Areas ◽  
Transport Model

Natural Bioactive Compounds As Adjuvant Therapy For Hepatitis C Infection

2020 ◽  
Vol 16 ◽  
Author(s):  
Moema S. Santana ◽  
Rute Lopes ◽  
Isabela H. Peron ◽  
Carla R. Cruz ◽  
Ana M. M. Gaspar ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Bioactive Compounds ◽  
Low Cost ◽  
Chemical Diversity ◽  
Acute Hepatitis C ◽  
Hepatitis C Infection ◽  
Middle Income ◽  
Broad Perspective ◽  
Cost Of Production

Background: Hepatitis C virus infection is a significant global health burden, which causes acute or chronic hepatitis. The acute hepatitis C is generally asymptomatic and progresses to cure, while persistent infection can progress to chronic liver disease and extrahepatic manifestations. Standard treatment is expensive, poorly tolerated, and has variable sustained virologic responses amongst the different viral genotypes. New therapies involve direct acting antivirals; however, it is also very expensive and may not be accessible for all patients worldwide. In order to provide a complementary approach to the already existing therapies, natural bioactive compounds are investigated as to their several biologic activities, such as direct antiviral properties against hepatitis C, and effects on mitigating chronic progression of the disease, which includes hepatoprotective, antioxidant, anticarcinogenic and anti-inflammatory activities; additionally, these compounds present advantages, as chemical diversity, low cost of production and milder or inexistent side effects. Objective: To present a broad perspective on hepatitis C infection, the chronic disease, and natural compounds with promising anti-HCV activity. Methods: This review consists of a systematic review study about the natural bioactive compounds as a potential therapy for hepatitis C infection. Results: The quest for natural products have yielded compounds with biologic activity, including viral replication inhibition in vitro, demonstrating antiviral activity against hepatitis C. Conclusion: One of the greatest advantages of using natural molecules from plant extracts is the low cost of production, not requiring chemical synthesis, which can lead to less expensive therapies available to low and middle-income countries.

Programmable Integrated Photonics

2020 ◽  
Author(s):  
José Capmany ◽  
Daniel Pérez
Keyword(s):  
Integrated Circuit ◽  
Performance Monitoring ◽  
Low Cost ◽  
Limiting Factors ◽  
External Control ◽  
Integrated Photonics ◽  
New Paradigm ◽  
Photonic Integrated Circuit ◽  
And Performance ◽  
Application Fields

Programmable Integrated Photonics (PIP) is a new paradigm that aims at designing common integrated optical hardware configurations, which by suitable programming can implement a variety of functionalities that, in turn, can be exploited as basic operations in many application fields. Programmability enables by means of external control signals both chip reconfiguration for multifunction operation as well as chip stabilization against non-ideal operation due to fluctuations in environmental conditions and fabrication errors. Programming also allows activating parts of the chip, which are not essential for the implementation of a given functionality but can be of help in reducing noise levels through the diversion of undesired reflections. After some years where the Application Specific Photonic Integrated Circuit (ASPIC) paradigm has completely dominated the field of integrated optics, there is an increasing interest in PIP justified by the surge of a number of emerging applications that are and will be calling for true flexibility, reconfigurability as well as low-cost, compact and low-power consuming devices. This book aims to provide a comprehensive introduction to this emergent field covering aspects that range from the basic aspects of technologies and building photonic component blocks to the design alternatives and principles of complex programmable photonics circuits, their limiting factors, techniques for characterization and performance monitoring/control and their salient applications both in the classical as well as in the quantum information fields. The book concentrates and focuses mainly on the distinctive features of programmable photonics as compared to more traditional ASPIC approaches.

scholarly journals Influence of Chemical Osmosis on Solute Transport and Fluid Velocity in Clay Soils

2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han
Keyword(s):  
Solute Transport ◽  
Transport Model ◽  
Fluid Velocity ◽  
Diffusion Mechanism ◽  
Clay Material ◽  
Chemical Osmosis ◽  
Advection Diffusion Equation ◽  
Test Study ◽  
Proposed Model ◽  
Membrane Effect

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.

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