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- Atmospheric Pollution (15)
- Catalysis (5)
- Heterogeneous catalysis (5)
- Greenhouse Gas Emissions (4)
- Indoor air quality (4)
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- Zeolite Synthesis (4)
- Biodiesel (3)
- Energy (3)
- Forest Fires (3)
- Portugal (3)
- Zeolites (3)
- Environmental Engineering (2)
- Heterogeneous Catalysts (2)
- Ionothermal synthesis (2)
- Kraft Pulp Mills ; Atmospheric Emissions (2)
- Lubricant oil (2)
- Nanocrystals (2)
- Nanoparticles (2)
- Toxicology (2)
- Unit operations and transport phenomena (2)
- Water sorption (2)
- Welding (2)
- Zeolite (2)
- Acid oils (1)
- Air Emissions (1)
- AlPO-18 (1)
- Ambient air (1)
- Antioxidant (1)
- Artificial Turf (1)
- Biodiesel ; heterogeneous catalysts ; hydrotalcites (1)
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Articles 1 - 30 of 50
Full-Text Articles in Nanoscience and Nanotechnology
Nanonickel Catalyst Reinforced With Silicate For Methane Decomposition To Produce Hydrogen And Nanocarbon: Synthesis By Co-Precipitation Cum Modified Stöber Method, Upm Ashik, Wma Wan Daud
Nanonickel Catalyst Reinforced With Silicate For Methane Decomposition To Produce Hydrogen And Nanocarbon: Synthesis By Co-Precipitation Cum Modified Stöber Method, Upm Ashik, Wma Wan Daud
upm ashik
Co-precipitation cum modified Stöber method is a continuous process avoiding application of higher temperature treatment before supporting nanometal with SiO2, irrespective of pre-preparation methods. We have conducted the co-precipitation process without undertaking calcination under air in order to avoid even a partial particle agglomeration and hence maintained average particle size [similar]30 nm after enforcing with SiO2. This is the first report adopting such an unceasing preparation for preparing metal/silicate nanostructures. Furthermore, n-Ni/SiO2 nanostructured catalysts were used for thermocatalytic decomposition of methane to produce hydrogen and carbon nanotubes. The catalyst was found to be very stable and the methane transformation activity …
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.
Capturing Ultrasmall Emt Zeolite From Template-Free Systems, Eng-Poh Ng Dr.
Capturing Ultrasmall Emt Zeolite From Template-Free Systems, Eng-Poh Ng Dr.
Eng-Poh Ng
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.
Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr.
Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr.
Eng-Poh Ng
Lubricants play a significant part in current environmental considerations since they are an integral and indispensable component of modern technology. The production, application and disposal of the lubricants have to follow increasingly strict requirements for protecting the environment and living organisms. In this respect, molecular sieve (LTL type zeolite) is investigated as a potential environmentally friendly alternative to traditional antioxidant additives for lubricant oils. Accelerated oxidation experiments using pure base oil and additivated base oil in the presence of the LTL molecular sieve are carried out in parallel, and the oxidation processes are monitored by FT-IR spectroscopy, spectrophotometry, chromatography, total …
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.
Micro- To Macroscopic Observations Of Mnalpo-5 Nanocrystal Growth In Ionic-Liquid Media, Eng-Poh Ng Dr.
Micro- To Macroscopic Observations Of Mnalpo-5 Nanocrystal Growth In Ionic-Liquid Media, Eng-Poh Ng Dr.
Eng-Poh Ng
Micro- and macroscopic studies of nucleation and growth processes of MnAlPO-5 nanosized crystals under ionothermal synthesis conditions are reported herein. The samples treated at 150 8C were extracted from the reaction mixture at various stages of crystallization, and characterized by XRD; SEM; thermogravimetric analysis (TGA); 31P and 27Al solid-state magic angle spinning (MAS) NMR, Raman, UV/Vis, and X-ray fluorescence spectroscopy (XRF). The starting raw materials (alumina, manganese, and phosphorous) were dissolved completely in the ionic liquid and transformed into an amorphous solid after 5 h of ionothermal treatment. This amorphous solid then undergoes structural changes over the following 5–25 h, …
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.
Discrete Mnalpo-5 Nanocrystals Synthesized By An Ionothermal Approach, Eng-Poh Ng, Satpal Singh Sekhon, Svetlana Mintova
Discrete Mnalpo-5 Nanocrystals Synthesized By An Ionothermal Approach, Eng-Poh Ng, Satpal Singh Sekhon, Svetlana Mintova
Eng-Poh Ng
Discrete MnAlPO-5 nanocrystals with monomodal particle size distribution (diameter of 80 nm) were synthesized using an ionothermal technique; the pore filling effect of the ionic liquid molecules during the synthesis of microporous nanocrystals is verified.
Selective Capture Of Water Using Microporous Adsorbents To Increase The Lifetime Of Lubricants, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova
Selective Capture Of Water Using Microporous Adsorbents To Increase The Lifetime Of Lubricants, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova
Eng-Poh Ng
Eco-recycling towards an increase of the lifetime of lubricating mineral oil by selective capturing of water with nanosized microporous aluminophosphate and aluminosilicate materials is reported. Quantitative water measurements of oxidized lubricating oil before and after treatment with microporous materials were carried out by FT-IR spectroscopy combined with Karl Fischer titration method. The high selectivity of the nanosized aluminophosphate to water without adsorbing other additives in comparison to nanosized aluminosilicates that are adsorbing altogether polar oxidation products, ionic additives and water are revealed. A removal of nearly 98 % of moisture from the lubricating oil at ambient condition is achieved, which …
Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova
Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova
Eng-Poh Ng
The main types of nanoporous adsorbents for water are identified and described with emphasis on the mechanism of adsorption, modification, improvement of the water sorption capacity, possible regeneration, and stabilization. Among the three main groups of water sorbents, i.e. inorganic materials (zeolites, clays, silica), carbon based materials and organic polymers, the first one is described in details. The significance of their porosity, chemical and structural features relative to the water adsorptive properties of each inorganic type materials is reviewed. Important features for silicates, zeolites, aluminophosphates, mesoporous materials and clays are described, which define the interactions between the water and the …
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.
Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle
Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle
Eng-Poh Ng
AlPO-18 layers were prepared on Si wafers via spin-coating or the Langmuir−Blodgett (LB) method using nanosized crystals. Multilayers were deposited by spin-coating, whereas the seeds assembled by the LB technique were monolayers. The seeded layers were not stable upon secondary growth under microwave radiation, and no films were formed on the supports. Dense AlPO-18 films could be obtained by secondary growth after stabilization of the seed layers by adding prehydrolyzed tetraethylorthosilicate (TEOS) to the colloidal AlPO-18 suspension prior to support seeding. The stabilized seed layers and the grown AlPO-18 films were stable. The structure and the morphology of the films …
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.