Performance of plant produced HMA mixtures with high RAP content in terms of low temperature cracking, fatigue cracking, and moisture induced damage

The Use of Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt Mixtures (HMA) has become a regular practice in the United States. Nowadays, many State DOTs are comfortable using RAP contents up to 20%. However, the need to include higher percentages of RAP in mixtures is increasing due to the increase of virgin material prices. Concerns about low temperature cracking, fatigue cracking and the potential need to bump binder grades limit the amounts of RAP in HMA mixtures. Moisture damage is an issue in some regions as well. This study presents testing and analysis results of plant produced mixtures with different RAP contents up to 40%. Results showed that including high RAP content as well as using stiffer binders may decrease mixture compliance, increase dynamic and relaxation moduli. It also generally leads to relatively warmer cracking temperature, and better fatigue performance. For moisture damage, all mixtures have relatively acceptable resistance

Risk factors for Autistic Spectrum Disorders at Assiut City

Autism is a neurological disorder characterized by qualitative impairments in social interaction, qualitative impairments in communication, and restricted repetitive, stereotyped patterns of behavior, interests, and activities. Autistic Spectrum Disorders are relatively common without known etiology can be found in 80-90% of cases. The aim of this study is to recognize the risk factors for Autistic Spectrum Disorders at Assiut City. The study was descriptive research design; it was conducted in all autism centers at Assiut city which includes 7 centers and included 47 parents who agree to participate in this study selected by convenient sample. The study included a structured interview sheet; this sheet divided into two parts Socio demographic characteristics, and parent’s knowledge about risk factors of Autism. The main findings of the study are: male represent a higher prevalence (72.3%) rate of autism than females (27.7%), and autistic children were more prevalent among families living in urban areas (80.9%) than rural (19.1%). The present study clears that (63.8%) of the fathers and 61.7% of the mothers had university level, the majority (85.1%) of autistic parents’ children hadn’t consanguinity degree while only (14.9%) from them had consanguinity from first degree (cousin), the vast majorities (97.9%) of studied children haven’t family history of autism; the present study found that all mothers of studied children hadn't any history of rubella, diabetes, thyroid and infectious diseases while only (4.3%) were exposed to eclampsia. The study recommended that, increase of public awareness about the risk factors of autism and its prevention by community leaders, mass media, and others especially at rural area. The curriculum of medicine and nursing faculties should include the Autistic Spectrum Disorder (risk factors, diagnosis and different treatment methods). Further studies should be conducted and gained a lot of attention for Autistic children and their parents. Key wards: Autism - Autism Spectrum Disorders – Risk factor

New approaches to the modelling of multi-component fuel droplet heating and evaporation

The previously suggested quasi-discrete model for heating and evaporation of complex multi-component hydrocarbon fuel droplets is described. The dependence of density, viscosity, heat capacity and thermal conductivity of liquid components on carbon numbers n and temperatures is taken into account. The effects of temperature gradient and quasi-component diffusion inside droplets are taken into account. The analysis is based on the Effective Thermal Conductivity/Effective Diffusivity (ETC/ED) model. This model is applied to the analysis of Diesel and gasoline fuel droplet heating and evaporation. The components with relatively close n are replaced by quasi-components with properties calculated as average properties of the a priori defined groups of actual components. Thus the analysis of the heating and evaporation of droplets consisting of many components is replaced with the analysis of the heating and evaporation of droplets consisting of relatively few quasi-components. It is demonstrated that for Diesel and gasoline fuel droplets the predictions of the model based on five quasi-components are almost indistinguishable from the predictions of the model based on twenty quasi-components for Diesel fuel droplets and are very close to the predictions of the model based on thirteen quasi-components for gasoline fuel droplets. It is recommended that in the cases of both Diesel and gasoline spray combustion modelling, the analysis of droplet heating and evaporation is based on as little as five quasi-components

Biomass Carbonization

Carbonization is the art of reinventing the waste biomass into a carbon−/energy-rich charcoal. It redefines the principles of renewable energy and power generation. Char is produced by a pyrolysis process in which the biomass is heated in an inert atmosphere to high temperatures until absorbed volatiles are expelled thus enriching its heating value and energy content. Carbonization itself is an old process that is being used till now, but the renewed interest in it especially with biomass is because it opens new doors for commercial and scientific applications. The carbon can be extracted from the produced char to form the precious graphite and graphene. This chapter provides a general overview about slow pyrolysis processes including carbonization and the torrefaction process which is a mild carbonization process. The characterization of different biomass species and their effect on the carbonization process and the final product will be also discussed. Different carbonization processes and methodologies which vary in the process parameters will be addressed, and the most promising ones will be highlighted. An important addition to this chapter is the general design parameters, methodologies, and factors that must be taken into consideration when designing carbonization reactors for lab and industrial designs

Modelling of blended Diesel and biodiesel fuel droplet heating and evaporation

The paper presents a new approach to the modelling of heating and evaporation of dual-fuel droplets with a specific application to blends of biodiesel (represented by the widely used soybean methyl ester, SME) and Diesel fuels in conditions representative of internal combustion engines. The original compositions, with up to 105 components of Diesel and biodiesel fuels, are replaced with a smaller number of components and quasi-components using the recently introduced multi-dimensional quasi-discrete (MDQD) model. Transient diffusion of these components and quasi-components in the liquid phase and temperature gradient and recirculation inside droplets are taken into account. The results are compared with the predictions of the case when blended biodiesel/Diesel fuel droplets are represented by pure biodiesel fuel or pure Diesel fuel droplets. It is shown that droplet evaporation time and surface temperature predicted for 100% SME, representing pure biodiesel fuel, are close to those predicted for pure Diesel fuel. Also, it is shown that the approximations of the actual compositions of B5 (5% SME and 95% Diesel) and B50 (50% SME and 50% Diesel) dual-fuels by 17 quasi-components/components, using the MDQD model, lead to under-predictions in droplet lifetimes by up to 9% and 4%, respectively, under the same engine conditions. The application of the latter model has resulted in above 83% reduction in CPU time compared to the case when all 105 components are taken into account using the discrete component model

A model for mono- and multi-component droplet heating and evaporation and its implementation into ANSYS Fluent

[EN] A model for heating and evaporation of mono- and multi-component droplets, based on analytical solutions to the heat transfer and species diffusion equations in the liquid phase, is summarised. The implementation of the model into ANSYS Fluent via User-Defined Functions (UDF) is described. The model is applied to the analysis of pure acetone, ethanol, and mixtures of acetone/ethanol droplet heating/cooling and evaporation. The predictions of the customised version of ANSYS Fluent with the newly implemented UDF model are verified against the results predicted by the previously developed in house, one-dimensional code.The authors would like to recognise that this work was supported by the UK’s Engineering and Physical Science Research Council, a studentship to support one of the authors (LP) [EPSRC grant EP/N509607/1; EP/K005758/1; EP/K020528/1; EP/M002608/1]Poulton, L.; Rybdylova, O.; Sazhin, SS.; Crua, C.; Qubeissi, M.; Elwardany, AE. (2017). A model for mono- and multi-component droplet heating and evaporation and its implementation into ANSYS Fluent. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 67-74. https://doi.org/10.4995/ILASS2017.2017.4759OCS677

A model for multi-component droplet heating and evaporation and its implementation into ANSYS Fluent

The main ideas of the model for multi-component droplet heating and evaporation, based on the analytical solutions to the heat conduction and species diffusion equations in the liquid phase, and its implementation into ANSYS Fluent CFD software are described. The model is implemented into this software via User-Defined Functions (UDF). The predictions of ANSYS Fluent with the newly implemented model are verified against the results predicted by the previously developed in-house research code for droplets comprising of a mixture of ethanol and acetone evaporating and cooled down in ambient air.Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in International Communications in Heat and Mass Transfer. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Communications in Heat and Mass Transfer, [90, (2017)] DOI: 10.1016/j.icheatmasstransfer.2017.10.018© 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/<br/