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Nanoscience and Nanotechnology Commons™
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- Keyword
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- Atmospheric Pollution (15)
- Catalysis (4)
- Greenhouse Gas Emissions (4)
- Indoor air quality (4)
- Biodiesel (3)
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- Energy (3)
- Forest Fires (3)
- Portugal (3)
- Environmental Engineering (2)
- Heterogeneous Catalysts (2)
- Kraft Pulp Mills ; Atmospheric Emissions (2)
- Toxicology (2)
- Unit operations and transport phenomena (2)
- Welding (2)
- Acid oils (1)
- Air Emissions (1)
- Ambient air (1)
- Artificial Turf (1)
- Biodiesel ; heterogeneous catalysts ; hydrotalcites (1)
- Biodiesel feedstock (1)
- Building downwash (1)
- CO2 ; Amines ; Flue Gases (1)
- CO2 ; dinamic model ; amine (1)
- CO2 absorption (1)
- Compliance (1)
- Corrosion (1)
- Dioxin (1)
- Dispersion of pollutants (1)
- Distillation ; McCabe and Thiele method ; Chemical Engineering Teaching (1)
- Dynamic simulation (1)
- Publication Year
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Articles 1 - 30 of 40
Full-Text Articles in Nanoscience and Nanotechnology
Biodiesel Production From Waste Trying Oils Over Lime Catalysts, João F. Gomes
Biodiesel Production From Waste Trying Oils Over Lime Catalysts, João F. Gomes
João F Gomes
No abstract provided.
Monitoring Exposure To Airborne Ultrafine Particles In Lisbon, Portugal, João F. Gomes
Monitoring Exposure To Airborne Ultrafine Particles In Lisbon, Portugal, João F. Gomes
João F Gomes
No abstract provided.
Comparison Of Deposited Surface Area Of Airborne Ultrafine Particles Generated From Two Welding Processes, João F. Gomes
Comparison Of Deposited Surface Area Of Airborne Ultrafine Particles Generated From Two Welding Processes, João F. Gomes
João F Gomes
No abstract provided.
Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes
Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes
João F Gomes
This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 ºC and 700 ºC, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1 % Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2 % FAME in the 2nd reaction step and 34 % FAME in the 3rd reaction …
Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes
Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes
João F Gomes
Small wastewater treatment plants (WWTP) are frequently located, by necessity, in remote and isolated sites, which increases the difficulty of its energy supply. Some of them are located near the seaside, in environmental sensible zones, and due to tourism activity of these sites, seasonal effects related with population size fluctuation can occur, which can originate certain inefficiencies concerning WWTP design and energy supply. The objective of this paper is to describe a step by step procedure for evaluation of the wind potential of sites that are dependent of in-situ energy generation, as well as, a case study on the utilization …
Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes
Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes
João F Gomes
Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is …
Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes
Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes
João F Gomes
A test chamber was projected and built (according to ISO 16000-9 Standard) to simulate atmospheric conditions experienced by rubber infill (when applied in synthetic turf pitches) and measure accurately the airborne emissions of pollutants such as dusts and volatile organic compounds (VOC), as well as pollutants present in leacheates. It should be pointed out that standard ISO 16000-9 is only concerned with the determination of the emission of VOC from building products and furnishing (not specific of synthetic turf materials), while other standards are concerned with the emission of leacheates only. This procedure is to be considered as a technical …
What Is A Chemical Engineer ?, João F. Gomes
On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes
On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes
João F Gomes
No abstract provided.
Advances On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes
Advances On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes
João F Gomes
This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work …
Study On The Activity Of New Amine Based Absorbents For Co2 Absorption From Flue Gases, João F. Gomes
Study On The Activity Of New Amine Based Absorbents For Co2 Absorption From Flue Gases, João F. Gomes
João F Gomes
The capture of CO2 from flue gases can be done by chemical absorption with aqueous amine solutions like MEA (monoethanolamine). Although this is a proven process, there are still operational problems to overcome [1], namely those resulting from solvent degradation, precipitation, corrosion and foaming. Also, the absorption capacity of the most current amines must be improved in order to obtain a more profitable operation. It has been shown previously that relationships exist between the amine structure and the activity/capacity for CO2 absorption. The introduction of amine substituents at the α-carbon creates a carbamate instability, which causes the hydrolysis to go …
A Simulation Study On The Abatement Of Co2 Emissions By De-Absorption, João F. Gomes
A Simulation Study On The Abatement Of Co2 Emissions By De-Absorption, João F. Gomes
João F Gomes
Due to the adverse effect of CO2 from fossil fuel combustion on the earth’s ecosystems, the most cost effective method for CO2 capture is an important area of research. The predominant process for CO2 capture currently employed by industry is chemical absorption in amine solutions. A dynamic model for the de-absorption process was developed with Monoethanolamine (MEA) solution. Henry’s law was used for modeling the vapour phase equilibrium of the CO2, and fugacity ratios calculated by the Peng Robinson equation of state (EOS) were used for H2O, MEA, N2 and O2. Chemical reactions between CO2 and MEA were included in …
Studies On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes
Studies On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes
João F Gomes
No abstract provided.
Endargement Of Undeveloped Areas Of Serbia By Forest Fires, João F. Gomes
Endargement Of Undeveloped Areas Of Serbia By Forest Fires, João F. Gomes
João F Gomes
Considering the significance of discovering the causes of forest fires, the hypothesis on the solar activity is presented (i.e. physical–chemical characteristics of the solar wind) as the possible cause of these natural disasters. The empirical confirmation of the mentioned hypothesis was disabled by the non existence of an adequate data base on the (regional) distribution of the number of fires and burned areas on the level of Serbia. Therefore an emphasis is put on theoretical explanations, but also on the characteristic situations in which there is an agreement between the processes occurring on the Sun and fire phenomena in the …
2008 Report Of Crerg Research Activities, João F. Gomes
2008 Report Of Crerg Research Activities, João F. Gomes
João F Gomes
No abstract provided.
Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes
Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes
João F Gomes
This paper describes the study that led to the development of a carbon dioxide emissions matrix for the Oeiras municipality, one of the largest Portuguese municipalities, located in the metropolitan area of Lisbon. This matrix takes into account the Greenhouse Gases (GHG) Emissions, due an increase of electricity demand in buildings as well as solid and liquid wastes treatment, from the domestic and services sectors. Using emission factors that were calculated from the relationship between the electricity produced and amount of treated wastes, the GHG emissions in the Oeiras municipality, were estimated for a time series of 6 years (1998 …
Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes
Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes
João F Gomes
CO2 capture from combustion flue gases is currently an issue of main interest due to the high taxes being imposed on industrial companies as a measure to achieve CO2 emissions abatement. CO2 capture can be efficiently achieved by gas absorption using amines, namely Monoethanolamine (MEA). Based on henrys law, validated with previously published experimental work, this study considers the development of a dynamic model of an absorption column for post combustion CO2 capture. A dynamic model of the temperature swing de-absorption process was developed with the integration of both models for absorption and de-absorption (with the introduction of heat exchangers, …
Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes
Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes
João F Gomes
This paper analyses the current energy balance of Portugal, considering the actual sources which are mainly traditional fossil fuels, hydroelectric power and renewables. Other potential sources are discussed also and taken into consideration in view of the previewed evolution of the country in energetic terms. Among these, nuclear power, once regarded as an option, is now being re-considered. This paper also sums up the main issues to be considered in a future debate on the subject.
Assessing The Possibility Of Corrosion Occurrence In Metallic Stacks Caused By Hydrochloric Acid, João F. Gomes
Assessing The Possibility Of Corrosion Occurrence In Metallic Stacks Caused By Hydrochloric Acid, João F. Gomes
João F Gomes
This article presents a simple method to estimate the possibility of corrosion in metallic stacks and surfaces due to hydrochloric acid deposition from stack gases, based on the HCl content in gases and also the flue gas temperature
New Technologies For Effective Forest Fire Fighting, João Gomes
New Technologies For Effective Forest Fire Fighting, João Gomes
João F Gomes
Efficient fire extinction with water could be greatly improved by using superabsorbent polymers, added to the water used for fire fighting, or sprayed over surfaces of combustible materials in order to protect them from fire. Specially developed superabsorbent polymers such as acrylamide/2-acrylamide-2-methyl-propane-sulphonate (AA/AMPS) seem to be particularly efficient for this purpose. In terms of water absorption, the experimental tests performed, showed that the optimal composition of this polymer is 30:70 AMPS versus AA, using 0.5% of bis-acrylamide (BA) as crosslinking agent.
Deriving An Indoor Environmental Index For Portuguese Office Buildings, João F. Gomes
Deriving An Indoor Environmental Index For Portuguese Office Buildings, João F. Gomes
João F Gomes
The EC issued a Directive in 2002 aiming to reduce the energy consumption of buildings, which was adopted by the EU member states and came into force in 2006. Portugal adopted it by issuing law decrees in 2006 which considered not only the energy saving aspects but also additional specific measures aiming to protect indoor air quality (IAQ). This new legislation is now being enforced and it will be necessary to define compliance acceptance levels for the prescribed indoor air limits. The use of comfort or environmental indexes could be of considerable help in order to ameliorate the evaluation of …
The Importance Of Considering Building Downwash When Assessing The Need To Heighten Stacks Of Existing Small And Medium Sized Industries, João F. Gomes
João F Gomes
No abstract provided.
Measurements Of Indoor Air Pollutant Levels In A University Office Building, João F. Gomes
Measurements Of Indoor Air Pollutant Levels In A University Office Building, João F. Gomes
João F Gomes
This work consisted of a series of determinations performed in typical rooms of a building belonging to the Technical University of Lisbon, which is located in a central urban area of Lisbon. The main objective was to evaluate the Indoor Air Quality (IAQ) of the rooms so that further corrective measures could be taken if unsatisfactory IAQ levels were to be found. Correlations were derived, between indoor and outdoor pollutant concentrations, in order to assess the existence of contaminations coming from outside. Also, correlations were derived between total volatile organic compounds (VOC) concentrations and specific individual organic species measured in …
Reflections On The Use Of The Mccabe And Thiele Method, João F. Gomes
Reflections On The Use Of The Mccabe And Thiele Method, João F. Gomes
João F Gomes
This paper reflects on the continuity of teaching the McCabe and Thiele method on chemical engineering courses for understanding the vapour-liquid equilibrium phenomena involved in distillation. Some exercises comparing the results obtained by this method as well as by other accurate analytical methods are presented and solved, as they are taught in ISEL courses. Because of its accuracy and easiness of use, and also because of the fact as this method allows an easy visualisation of the whole operation itself, the McCabe and Thiele method continues to be widespread used and students show a remarkable adherence to it.
Forest Fires In Portugal: How They Happen And Why They Happen, João F. Gomes
Forest Fires In Portugal: How They Happen And Why They Happen, João F. Gomes
João F Gomes
Forest fires are recurrent phenomena in Southern European countries, due to the nature of Mediterranean forest and climatic characteristics. However, in Portugal, in the last years, forest fires attained the dimension of public calamity and are now endangering sustainability of forest itself, as well as several derived economic activities. This paper reviews the past and current situation of forest fires in Portugal, analyses its main causes and consequences and derives recommendations to effectively overcome this problem.
Leaching Of Heavy Metals From Steelmaking Slags, João F. Gomes
Leaching Of Heavy Metals From Steelmaking Slags, João F. Gomes
João F Gomes
Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most …
Estimation Of Uncertainty In The Determination Of Nitrogen Oxides Emissions, João F. Gomes
Estimation Of Uncertainty In The Determination Of Nitrogen Oxides Emissions, João F. Gomes
João F Gomes
This paper presents a methodology for estimation of uncertainty on a reference test method for determination of nitrogen oxides concentration in gaseous emissions from stationary sources. As a first stage for identification of uncertainty sources, the test method is carefully reviewed in detail. Afterwards, these sources are quantified, bearing in mind its partial uncertainty, allowing the determination of the combined uncertainty and, finally, the expanded uncertainty. The calculation procedure was implemented into an excel calculation file. Using this file and considering several numerical applications from real situations, uncertainities around 15 mg/Nm3 over determined concentrations of 350 mg/Nm3 of NOx (expressed …
Fume Emissions During Metal Arc Welding, João F. Gomes
Fume Emissions During Metal Arc Welding, João F. Gomes
João F Gomes
No abstract provided.
Avoid Sulfuric Acid Corrosion In Metallic Stacks, João F. Gomes
Avoid Sulfuric Acid Corrosion In Metallic Stacks, João F. Gomes
João F Gomes
Acidic gaseous effluents frequently cause corrosion on metallic stacks. This paper presents a method for prevision of probability of corrosion occurrence caused by gaseous effluents containing sulphur oxides which is based on the sulphur trioxide and moisture content measured in stack
Emissions Of Dioxin And Dibenzofuran From Electric Arc Furnaces, João F. Gomes
Emissions Of Dioxin And Dibenzofuran From Electric Arc Furnaces, João F. Gomes
João F Gomes
This paper describes work done in order to clarify the formation mechanism of highly toxic micropollutants, such as dioxins and dibenzofurans, from electric arc furnaces used in the production of carbon steel from scrap. The study is allowing to derive relationships between the levels of airborne micropollutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropollutants emitted by this particular stationary source.