Stability Of Thin Liquid Film Under Effect Of Apolar And Electrostatic Forces On A Horizontal Plane

The understanding of stability, dynamics and morphology of supported th (<100nm) liquid films and nanodrops are important in phenomena like flotation, adhesion of fluid particles to surfaces, kinetics and thermodynamics of precursor films in wetting, heterogeneous nucleation, film boiIing/condensation, multilayer adsorption/film pressure, instability of biological films/membranes, and many other areas While the wetting of surface by large drops is relatively well understood, wetting charactenstics of nanodrops and films have not been extensively studied in some applications like trickle bed reactors, thick coating, contact equipment for heat and mass transfer. and the like Factors that would affect the total free excess energy (per unit area) of a thin film on a substrate include the film thickness, as well as the apolar and electrostatic spreading coefficients for the system. The dynamics of the liquid film is formulated using the Navier-Stokes equations augmented by a body forces describing the apolar and electrostatic interactions

Characteristics and oil sorption effectiveness of kapok fiber, sugarcane bagasse and rice husks: Oil removal suitability matrix

The characteristics and water/oil sorption effectiveness of kapok fiber, sugarcane bagasse and rice husks have been compared. The three biomass types are subjected to field-emission scanning electron microscopy-energy dispersive x-ray spectroscopy while the surface tension analyses for liquid-air and oil-water systems have also been conducted. Both kapok fiber and sugarcane bagasse exhibit excellent oil sorption capabilities for diesel, crude, new engine and used engine oils since all their oil sorption capacities exceed 10 g/g. Synthetic sorbent exhibits oil sorption capacities comparable to sugarcane bagasse while rice husks exhibit the lowest oil sorption capacities among all the sorbents. Kapok fiber shows overwhelmingly high oil-to-water sorption (O/W) ratios ranging from 19.35 to 201.53 while sugarcane bagasse, rice husks and synthetic sorbent have significantly lower O/W ratios (0.76 to 2.69). This suggests that kapok fiber is a highly-effectual oil sorbent even in well-mixed oil-water media. An oil sorbent suitability matrix has been proposed to aid relevant stakeholders for evaluation of customized oil removal usage of the natural sorbents

Date Palm Leaflet-Derived Carbon Microspheres Activated Using Phosphoric Acid for Efficient Lead (II) Adsorption

\ua9 2024 by the authors.The removal of lead metals from wastewater was carried out with carbon microspheres (CMs) prepared from date palm leaflets using a hydrothermal carbonization process (HTC). The prepared CMs were subsequently activated with phosphoric acid using the incipient wetness impregnation method. The prepared sample had a low Brunauer–Emmet–Teller (BET) surface area of 2.21 m2\ub7g−1, which increased substantially to 808 m2\ub7g−1 after the activation process. Various characterization techniques, such as scanning electron microscopy, BET analysis, Fourier transform infrared, and elemental analysis (CHNS), were used to evaluate the morphological structure and physico-chemical properties of the CMs before and after activation. The increase in surface area is an indicator of the activation process, which enhances the absorption properties of the material. The results demonstrated that the activated CMs had a notable adsorption capacity, with a maximum adsorption capacity of 136 mg\ub7g−1 for lead (II) ions. This finding suggests that the activated CMs are highly effective in removing lead pollutants from water. This research underscores the promise of utilizing activated carbon materials extracted from palm leaflets as an eco-friendly method with high potential for water purification, specifically in eliminating heavy metal pollutants, particularly lead (II), contributing to sustainability through biomass reuse

Estimation of PM10-bound As, Cd, Ni and Pb levels by means of statistical modelling: PLSR and ANN approaches

Air quality assessment regarding metals and metalloids using experimental measurements is expensive and time consuming due to the cost and time required for the analytical determination of the levels of these pollutants. According to the European Union (EU) Air Quality Framework Directive (Directive 2008/50/EC), other alternatives, such as objective estimation techniques, can be considered for ambient air quality assessment in zones and agglomerations where the level of pollutants is below a certain concentration value known as the lower assessment threshold. These conditions occur in urban areas in Cantabria (northern Spain). This work aims to estimate the levels of As, Cd, Ni and Pb in airborne PM10 at two urban sites in the Cantabria region (Castro Urdiales and Reinosa) using statistical models as objective estimation techniques. These models were developed based on three different approaches: partial least squares regression (PLSR), artificial neural networks (ANNs) and an alternative approach consisting of principal component analysis (PCA) coupled with ANNs (PCA-ANN). Additionally, these models were externally validated using previously unseen data. The results show that the models developed in this work based on PLSR and ANNs fulfil the EU uncertainty requirements for objective estimation techniques and provide an acceptable estimation of the mean values. As a consequence, they could be considered as an alternative to experimental measurements for air quality assessment regarding the aforementioned pollutants in the study areas while saving time and resources.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the Project CMT2010-16068. The authors also thank the Regional Environment Ministry of the Cantabria Government for providing the PM10 samples at the Castro Urdiales and Reinosa sites

Development of educational software for designing shell-and-tube heat exchangers

A framework for developing educational software using the Visual Basic (VB) programming language for designing shell-and-tube heat exchangers (based on Kern and Bell-Delaware methods) is presented in this study. Simulation values from the software have been validated using manual calculations and compared with those from related software (HEXTRAN)

Design and Development of an Integrated Chemical Accident System for Monitoring Risk Potential of Hazard Installation

Mathematical models are extremely useful tools to predict the impacts of chemical process accidents. The applications of these models require competency in mathematics and computer programming. Therefore the procedural and methodology for the calculation of consequences and risks from installations handling toxic or flammable materials have been computerized by using a software called the Simulation of Chemical Industrial Accidents (SCIA). The SCIA software was successfully developed using Visual Basic (VB) programming language with integration of GIS tools. The explosion, fire and toxic release models are implemented in an interactive VB environment. The first step to evaluate the hazard consequence by using the SCIA software is to select whether the material is a toxic or flammable substance which is accidentally released into the environment, the specification of the position of the installations, and of all the damage states under analysis. For each and every plant damage state the following tasks are performed. An outflow model calculates the rate of release of the hazardous substance. For a toxic material the software will precede the dispersion calculations, in order to estimate the concentration of the substance in the environment. In the case of a flammable substance a distinction is made on whether an immediate or a delayed ignition will occur. If the flammable substance along with the plant damage state results in an immediate ignition, an appropriate model is called to calculate the resulting thermal radiation. If delayed ignition is appropriate, the software will proceed to dispersion calculations to determine the explosive mass and its position in the resulting cloud. In the second step, the explosion, fire and toxic release models are used to calculate the overpressure, radiation and concentration effects around the site. Assessment of the dose follows the calculation of concentrations, thermal fluxes and overpressures as appropriate. The third step is to estimate the probability of fatality or injury that an individual will die or suffer as a result of its exposure to extreme phenomenon which is estimated in terms of dose-response models. All dose-response models employed in SCIA are based on a “probit” function for the substance and phenomenon. The results obtained from all three scenario models (explosion, fire and toxic release) were compared with results from previous software or data from real accidents, spreadsheets and manual calculations. However slight differences can be noticed with those results obtained from earlier studies. The final step is to present the hazard zones located in the vicinity of the accident area. This can be done by using GIS functionality to present the results as a circle around the point of release from the source. The software is capable of handling multiple and alternative accident scenarios, complex terrain dispersion, uncertain quantification (including parameter and model uncertainty) and is characterized by a user-friendly Graphic User Interface (GUI). Furthermore the software is linked to GIS for screening hazard displays. The development is done by customizing ArcGIS Engine using Visual Basic (VB). With ArcGIS Engine user can efficiently build and deploy custom desktop ArcGIS applications and use embedded GIS logic in non-GIS centric applications. Using the ArcGIS applications, users can create and manage maps used in custom applications which will save in development and effort. The results from SCIA software were extensively validated and compared with other commercial softwares such as: FRED (developed by Shell Global company, 2004), BIS (developed by ThermDyne Technologies Ltd, 2003), EFFECT (developed by TNO, 1987) and MAXCRED (developed by Khan and Abbasi, 1998) and with established data. It was observed that the difference between results from the SCIA software in comparison to the others can be considered insignificant. Furthermore the SCIA software has been developed successfully to be utilized as a stand alone application, which allows users to run the software independently on a PC. The SCIA software is useful due to various reasons; the cost of developing the software is cheap, the program size is small which enables users to run the application instantly, compatible to download for all windows operating systems, work as a stand alone application and finally contains a flexible database to add or delete records in the future. Furthermore the application includes an internal help option to provide and guide users with instructions to use the software. Therefore SCIA is considered as a user-friendly application

Synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: Microbial viabilities at different ionic liquids concentrations

Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimCn][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC50 values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity

Consequence analysis of catastrophic release of diesel and fuel oil from their storage tanks using SCIA software

Catastrophic release of diesel and fuel oil from their storage tanks can lead disasters to human, property and the environment. Thus consequences analysis of the accident has significant importance to human communities living in the surrounding area and the authorities involved in land planning. Consequence analysis is normally carried out using mathematical models for predicting the impacts of chemical accidents. This paper presents result of the consequence analysis from study cases namely catastrophic release of diesel and fuel oil from their storage tanks using Simulation of Chemical Industrial Accident (SCIA) software. The software is a user-friendly and effective tool for evaluating the consequences of major chemical accidents, process decision making for land-use planning, namely locating suitable hazardous installations, hazardous waste disposal areas and emergency response plan. Release of diesel and fuel oil might escalate to pool fires and thus require evaluating their characteristics and the posed hazard. It is recommended for future land planning and development, a town must be located at least half kilometre away from the storage tanks to minimize the disaster impacts

Estimating the flammability of vapours above refinery wastewater laden with hydrocarbon mixtures

In this study, the likelihood of fire hazards attributed to the vapourisation of hydrocarbon components derived from refinery wastewater drainage systems was assessed. Liquid samples containing mixtures of hydrocarbon products and water were collected from a refinery drainage system and subjected to a distillation process to separate oil and water. The oil–liquid phase was analysed using gas chromatography–mass spectrometry (GC–MS) to examine the composition of the sample. Hydrocarbon compounds ranging from C9 to C16 were detected. Mole fractions of 28 selected components in the liquid phase were obtained from the GC–FID data and used to calculate mole fractions of components in the gas phase via modified Raoult’s law. Lower Flammability Limits (LFLs) and Upper Flammability Limits (UFLs) for individual components were calculated using a stoichiometric concentration method, while the LFL and UFL values for the mixture (LFL mix and UFLmix) were calculated using the Le Chatelier equation. The LFL mix and UFLmix values were used to construct a flammability diagram and subsequently used to determine the flammability of the mixture. The findings of this study may assist in minimising fire hazards associated with the presence of hydrocarbon vapours derived from refinery wastewater streams