Sand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for deh... more Sand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for dehydrogenation of NaBH 4 in methanol. T and P sand samples were sieved to <250, 250 to 500, and >500 μm sizes, and the smallest fractions resulted in faster hydrogen generation rates (HGR), 565 ± 18 and 482 ± 24 mL H 2 (min.g of catalyst) −1 , respectively. After various base/acid treatments, HGR values of 705 ± 51 and 690 ± 47 mL H 2 (min g of catalyst) −1 for HCl-treated T and P sand samples were attained, respectively. Next, T and P sand samples were modified with polyethyleneimine (PEI) that doubled the HGR values, 1344 ± 103, and 1190 ± 87 mL H 2 (min.g of catalyst) −1 and increased $8-fold, 4408 ± 187, and 3879 ± 169 mL H 2 (min g of catalyst) −1 , correspondingly after protonation (PEI +). The Ea values of T and P sand samples were calculated as 24.6 and 25.9 kJ/mol, and increased to 36.1, and 36.6 kJ/mol for T-PEI + and P-PEI + samples, respectively.
Carbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/... more Carbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/ hexose and/or polysaccharides in addition to many starting materials by treatment of thermal, chemical and hydrothermal methods. Here, the porous carbon (PC) particles were prepared by removal of silica particles from previously prepared carbon-silica composites by hydrothermal and carbonization process from sucrose. Then, PC particles were modified with polyethyleneimine (PEI) to prepared amine functionalized PC-PEI particles and protonated with hydrochloric acid, PC-PEI þ. Finally, these prepared carbon-based particles were used as catalyst for H 2 release from NaBH 4 methanolysis and PC-PEI þ was found as the most effective catalyst at 25 C with 4040 ± 126 mL H 2. min À1 .g À1 HGR value. The E a value of 23.9 kJ/mol in H 2 release reaction from NaBH 4 methanolysis catalyzed by PC-PEI þ that is comparable and/ or better than most of studies reported in literature. The activity% of PC-PEI þ catalyst was 72% after fifth consequential runs. Additionally, the regeneration ability of PC-PEI þ catalyst was also shown that after fifth regeneration process, there is only 5% decrease in activity%.
ABSTRACT In this study, p(AMPS) hydrogels are synthesized from 2-acrylamido-2-methyl-1-propansulf... more ABSTRACT In this study, p(AMPS) hydrogels are synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) via a photo polymerization technique. The hydrogels are used as template for metal nanoparticles and magnetic ferrite nanoparticles, and also as a catalysis vessel in the generation of hydrogen from the hydrolysis of NaBH4. Approximately 5 nm Ru (0) and 20–30 nm magnetic ferrite particles are generated in situ inside this p(AMPS) hydrogel network and then used as a catalysis medium in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. With an applied external magnetic field, the hydrogel reactor, containing Ru and ferrite magnetic particles, can be removed from the catalysis medium; providing on-demand generation of hydrogen. The effect of various parameters such as the initial concentration of NaBH4, the amount of catalyst and temperature on the hydrolysis reaction is evaluated. The activation energy for hydrogen production by Ru (0) nanoparticles is found to be 27.5 kJ mol−1; while the activation enthalpy is 30.4 kJ mol−1. The hydrogen generation rate in presence of 5 wt% NaOH and 50 mg p(AMPS)-Ru catalyst is 8.2 L H2 min−1 g Ru.
We report the preparation of metal nanoparticles in various formulations inside p(2-acrylamido-2-... more We report the preparation of metal nanoparticles in various formulations inside p(2-acrylamido-2-methyl-1-propansulfonic acid; p(AMPS)) hydrogels and their utilization as a catalyst in hydrolysis of NaBH 4. The swollen, flexible p(AMPS) network was used for metal ion loading and reduction in situ for the preparation of Co:Ni nanoparticles as bimetallic clusters in various formulation, and Co and Ni bimetallic catalysts as Co þ Co, Co þ Ni, Ni þ Co and Ni þ Ni. In addition to utilization of hydrogels as support materials, the p(AMPS)-metal nanoparticle system was used as catalyst to generate hydrogen in the hydrolysis of NaBH 4 with very high yield. Various parameters for the hydrolysis reaction were determined and the activation parameters were calculated. For the first time, inclusion of ferrite magnetic particles to control hydrogen generation on demand by using an externally applied magnetic field to remove the hydrogel-catalyst system from the hydrolysis medium is reported.
In this study, hydrogels were synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS)... more In this study, hydrogels were synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) via a photo polymerization technique. Approximately 100 nm Ni metal nanoparticles were generated in situ inside these p(AMPS) hydrogel networks and used as a catalyst in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. The effects of several parameters on the hydrolysis reaction such as the amount of catalyst, the initial concentration of NaBH 4 , and the temperature were investigated. The activation energy, activation enthalpy and activation of entropy for the reaction were calculated as 42.28 kJ mol À1 , 39.59 kJ mol À1 and À171.67 J mol À1 K À1 , respectively.
Polymeric hydrogels derived from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were utilized... more Polymeric hydrogels derived from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were utilized in the preparation of cobalt (Co) metal nanoparticles and used as a composite-catalyst system in hydrogen generation from the hydrolysis of NaBH 4. The embedded Co nanoparticles in the p(AMPS) networks are on the order of 100 nm. It was demonstrated that the p(AMPS)-Co composite system was very effective in the production of hydrogen from alkali aqueous sodium boron hydride solutions. The effect of various parameters such as the initial concentration of NaBH 4 , the amount of catalyst and temperature on the hydrolysis reaction was evaluated. The activation energy for hydrogen production by Co particles was found to be 38.14 kJ mol −1 ; while the activation enthalpy was 35.46 kJ mol −1 .
Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin gelişt... more Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin geliştirilmesi planlanmaktadır. Uzay araçlarının yakıt ikmali için gerekli oksijen gibi ay malların yörüngedeki depolara taşınaması sağlanacaktır. Genel olarak aydan malzeme nakliyesi söz konusu olduğunda EMFS (Elektromanyetik Fırlatma Sistemi) teknolojisinin, yakın gelecekteki üstünlükleri çok iyi açıklanabilir. EMFS'nin kimyasal fırlatma sistemine göre, yüksek kapasiteli taşıma, yüksek güvenlik ve çevresel sürdürülebilirlik ile düşük bakım maliyetleri ve yüksek verimlilik gibi çeşitli avantajları bulunmaktadır. Sunulan ön konseptin geliştirilmesi ve bu tür bir sistemle dağıtımının fizibilite ve net faydası ile ilgili, yüksek yük taşıma kapasitesine sahip oluşu EMFS'yi desteklemektedir. EMFS halen sürdürülen bir çalışmadır ve özellikle donanım geliştirme aşamasında dikkate alınması gereken birçok zorlukları bulunmaktadır. Bu çalışmada Yüksek Sıcaklık Süperiletken (HTSC) MgB 2 gibi malzemeler, ana güç üretimi, veriyolu çalışması, endüktif enerji depolama, devre açma anahtarları, başlatıcı bobinler ve yükler dahil, birçok EMFS bileşenleri için yaygın olarak kullanılan uygulamalardır.
In this article, the flight of a mass driver was designed for launch from the Earth with Electro ... more In this article, the flight of a mass driver was designed for launch from the Earth with Electro Magnetic Space Launching System (EMSLS). Then the orbit exit from the Earth at 185 km and orbit entry the Moon at 100kmwere examined with respect to change of trajectories by using chemical fuel and the engine in the mass driver. Electromagnetically launched mass drivers should orbit with a specified orbital velocity at a designated altitude. In this paper, the energy is transferred externally to a mass driver throughout the flight path the electromagnetic coil system called multistage (EMSLS) designated in order to achieve the specified orbital velocity. The mass driver is synchronously accelerated by a voltage through the capacitors which are used for storing energy. This energy is transferred through a switching inductor to the circuit of the mass driver so that the mass driver is launched into the orbit with a muzzle velocity. However, this fact creates high air drag energy losses due to atmospheric conditions and high velocity obtained in EMSLS. Thus, in the mass driver at 21km altitude an engine starts to increase the velocity of the system to reach orbital velocity. The final aim of this article is to capture the transfer of v cost for traveling to the Moon. At any given arrival time in order to guide the system, designers only consider the gravity of the Earth and gravity of the Moon by using a Direct Lunar Transfer Trajectory for the Earth to the Moon approach. Finally, EMSLS was evaluated as a more advantageous and complimentary alternative to chemical propulsion systems for space transportation. INDEX TERMS Mass driver, electro magnetic space launching system (EMSLS), muzzle velocity, lunar transfer trajectory from earth, useful payload, V cost, perigee, apogee.
Elektromanyetik fırlatma sistemlerinin, Uzay taşımacılığında, kimyasal itkili sistemlerden daha u... more Elektromanyetik fırlatma sistemlerinin, Uzay taşımacılığında, kimyasal itkili sistemlerden daha uygun bir alternatif olacağı tartışılmıştır. Elektromanyetik fırlatma sistemindeki uçuş kütlesi, manyetik fırlatıcı içindeki uçuş hattı boyunca depolanmış elektrik enerjiyle yörünge hızına ulaştırılır. Kimyasal yakıt kullanan fırlatma sistemleri yörünge hızına ulaşmak için faydalı yüke ilave olarak yakıt ve yakıt sistemlerini de yörüngeye taşımak durumundadır. Faydalı yüke eşlik eden bu yakıt sistemleri ilave maliyet ve zaman gerektirir. Bu nedenler elektromanyetik fırlatma sistemlerini, kimyasal itki sistemlerinden daha avantajlı ve masraf etkin yapmaktadır. Literatür taramasında elektromanyetik fırlatma sisteminin teknolojik gelişim tarihi derlendi. Taşınacak kütle, ivme, hız, fırlatıcı uzunluğu ve elektromanyetik fırlatma sisteminin çeşidi teknolojik gelişimin ana konuları oldu. Tek kademeli ve çok kademeli olmak üzere mini ölçekli iki elektromanyetik fırlatma sistemi tasarlandı, üreti...
Sand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for deh... more Sand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for dehydrogenation of NaBH 4 in methanol. T and P sand samples were sieved to <250, 250 to 500, and >500 μm sizes, and the smallest fractions resulted in faster hydrogen generation rates (HGR), 565 ± 18 and 482 ± 24 mL H 2 (min.g of catalyst) −1 , respectively. After various base/acid treatments, HGR values of 705 ± 51 and 690 ± 47 mL H 2 (min g of catalyst) −1 for HCl-treated T and P sand samples were attained, respectively. Next, T and P sand samples were modified with polyethyleneimine (PEI) that doubled the HGR values, 1344 ± 103, and 1190 ± 87 mL H 2 (min.g of catalyst) −1 and increased $8-fold, 4408 ± 187, and 3879 ± 169 mL H 2 (min g of catalyst) −1 , correspondingly after protonation (PEI +). The Ea values of T and P sand samples were calculated as 24.6 and 25.9 kJ/mol, and increased to 36.1, and 36.6 kJ/mol for T-PEI + and P-PEI + samples, respectively.
Carbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/... more Carbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/ hexose and/or polysaccharides in addition to many starting materials by treatment of thermal, chemical and hydrothermal methods. Here, the porous carbon (PC) particles were prepared by removal of silica particles from previously prepared carbon-silica composites by hydrothermal and carbonization process from sucrose. Then, PC particles were modified with polyethyleneimine (PEI) to prepared amine functionalized PC-PEI particles and protonated with hydrochloric acid, PC-PEI þ. Finally, these prepared carbon-based particles were used as catalyst for H 2 release from NaBH 4 methanolysis and PC-PEI þ was found as the most effective catalyst at 25 C with 4040 ± 126 mL H 2. min À1 .g À1 HGR value. The E a value of 23.9 kJ/mol in H 2 release reaction from NaBH 4 methanolysis catalyzed by PC-PEI þ that is comparable and/ or better than most of studies reported in literature. The activity% of PC-PEI þ catalyst was 72% after fifth consequential runs. Additionally, the regeneration ability of PC-PEI þ catalyst was also shown that after fifth regeneration process, there is only 5% decrease in activity%.
ABSTRACT In this study, p(AMPS) hydrogels are synthesized from 2-acrylamido-2-methyl-1-propansulf... more ABSTRACT In this study, p(AMPS) hydrogels are synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) via a photo polymerization technique. The hydrogels are used as template for metal nanoparticles and magnetic ferrite nanoparticles, and also as a catalysis vessel in the generation of hydrogen from the hydrolysis of NaBH4. Approximately 5 nm Ru (0) and 20–30 nm magnetic ferrite particles are generated in situ inside this p(AMPS) hydrogel network and then used as a catalysis medium in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. With an applied external magnetic field, the hydrogel reactor, containing Ru and ferrite magnetic particles, can be removed from the catalysis medium; providing on-demand generation of hydrogen. The effect of various parameters such as the initial concentration of NaBH4, the amount of catalyst and temperature on the hydrolysis reaction is evaluated. The activation energy for hydrogen production by Ru (0) nanoparticles is found to be 27.5 kJ mol−1; while the activation enthalpy is 30.4 kJ mol−1. The hydrogen generation rate in presence of 5 wt% NaOH and 50 mg p(AMPS)-Ru catalyst is 8.2 L H2 min−1 g Ru.
We report the preparation of metal nanoparticles in various formulations inside p(2-acrylamido-2-... more We report the preparation of metal nanoparticles in various formulations inside p(2-acrylamido-2-methyl-1-propansulfonic acid; p(AMPS)) hydrogels and their utilization as a catalyst in hydrolysis of NaBH 4. The swollen, flexible p(AMPS) network was used for metal ion loading and reduction in situ for the preparation of Co:Ni nanoparticles as bimetallic clusters in various formulation, and Co and Ni bimetallic catalysts as Co þ Co, Co þ Ni, Ni þ Co and Ni þ Ni. In addition to utilization of hydrogels as support materials, the p(AMPS)-metal nanoparticle system was used as catalyst to generate hydrogen in the hydrolysis of NaBH 4 with very high yield. Various parameters for the hydrolysis reaction were determined and the activation parameters were calculated. For the first time, inclusion of ferrite magnetic particles to control hydrogen generation on demand by using an externally applied magnetic field to remove the hydrogel-catalyst system from the hydrolysis medium is reported.
In this study, hydrogels were synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS)... more In this study, hydrogels were synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) via a photo polymerization technique. Approximately 100 nm Ni metal nanoparticles were generated in situ inside these p(AMPS) hydrogel networks and used as a catalyst in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. The effects of several parameters on the hydrolysis reaction such as the amount of catalyst, the initial concentration of NaBH 4 , and the temperature were investigated. The activation energy, activation enthalpy and activation of entropy for the reaction were calculated as 42.28 kJ mol À1 , 39.59 kJ mol À1 and À171.67 J mol À1 K À1 , respectively.
Polymeric hydrogels derived from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were utilized... more Polymeric hydrogels derived from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were utilized in the preparation of cobalt (Co) metal nanoparticles and used as a composite-catalyst system in hydrogen generation from the hydrolysis of NaBH 4. The embedded Co nanoparticles in the p(AMPS) networks are on the order of 100 nm. It was demonstrated that the p(AMPS)-Co composite system was very effective in the production of hydrogen from alkali aqueous sodium boron hydride solutions. The effect of various parameters such as the initial concentration of NaBH 4 , the amount of catalyst and temperature on the hydrolysis reaction was evaluated. The activation energy for hydrogen production by Co particles was found to be 38.14 kJ mol −1 ; while the activation enthalpy was 35.46 kJ mol −1 .
Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin gelişt... more Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin geliştirilmesi planlanmaktadır. Uzay araçlarının yakıt ikmali için gerekli oksijen gibi ay malların yörüngedeki depolara taşınaması sağlanacaktır. Genel olarak aydan malzeme nakliyesi söz konusu olduğunda EMFS (Elektromanyetik Fırlatma Sistemi) teknolojisinin, yakın gelecekteki üstünlükleri çok iyi açıklanabilir. EMFS'nin kimyasal fırlatma sistemine göre, yüksek kapasiteli taşıma, yüksek güvenlik ve çevresel sürdürülebilirlik ile düşük bakım maliyetleri ve yüksek verimlilik gibi çeşitli avantajları bulunmaktadır. Sunulan ön konseptin geliştirilmesi ve bu tür bir sistemle dağıtımının fizibilite ve net faydası ile ilgili, yüksek yük taşıma kapasitesine sahip oluşu EMFS'yi desteklemektedir. EMFS halen sürdürülen bir çalışmadır ve özellikle donanım geliştirme aşamasında dikkate alınması gereken birçok zorlukları bulunmaktadır. Bu çalışmada Yüksek Sıcaklık Süperiletken (HTSC) MgB 2 gibi malzemeler, ana güç üretimi, veriyolu çalışması, endüktif enerji depolama, devre açma anahtarları, başlatıcı bobinler ve yükler dahil, birçok EMFS bileşenleri için yaygın olarak kullanılan uygulamalardır.
In this article, the flight of a mass driver was designed for launch from the Earth with Electro ... more In this article, the flight of a mass driver was designed for launch from the Earth with Electro Magnetic Space Launching System (EMSLS). Then the orbit exit from the Earth at 185 km and orbit entry the Moon at 100kmwere examined with respect to change of trajectories by using chemical fuel and the engine in the mass driver. Electromagnetically launched mass drivers should orbit with a specified orbital velocity at a designated altitude. In this paper, the energy is transferred externally to a mass driver throughout the flight path the electromagnetic coil system called multistage (EMSLS) designated in order to achieve the specified orbital velocity. The mass driver is synchronously accelerated by a voltage through the capacitors which are used for storing energy. This energy is transferred through a switching inductor to the circuit of the mass driver so that the mass driver is launched into the orbit with a muzzle velocity. However, this fact creates high air drag energy losses due to atmospheric conditions and high velocity obtained in EMSLS. Thus, in the mass driver at 21km altitude an engine starts to increase the velocity of the system to reach orbital velocity. The final aim of this article is to capture the transfer of v cost for traveling to the Moon. At any given arrival time in order to guide the system, designers only consider the gravity of the Earth and gravity of the Moon by using a Direct Lunar Transfer Trajectory for the Earth to the Moon approach. Finally, EMSLS was evaluated as a more advantageous and complimentary alternative to chemical propulsion systems for space transportation. INDEX TERMS Mass driver, electro magnetic space launching system (EMSLS), muzzle velocity, lunar transfer trajectory from earth, useful payload, V cost, perigee, apogee.
Elektromanyetik fırlatma sistemlerinin, Uzay taşımacılığında, kimyasal itkili sistemlerden daha u... more Elektromanyetik fırlatma sistemlerinin, Uzay taşımacılığında, kimyasal itkili sistemlerden daha uygun bir alternatif olacağı tartışılmıştır. Elektromanyetik fırlatma sistemindeki uçuş kütlesi, manyetik fırlatıcı içindeki uçuş hattı boyunca depolanmış elektrik enerjiyle yörünge hızına ulaştırılır. Kimyasal yakıt kullanan fırlatma sistemleri yörünge hızına ulaşmak için faydalı yüke ilave olarak yakıt ve yakıt sistemlerini de yörüngeye taşımak durumundadır. Faydalı yüke eşlik eden bu yakıt sistemleri ilave maliyet ve zaman gerektirir. Bu nedenler elektromanyetik fırlatma sistemlerini, kimyasal itki sistemlerinden daha avantajlı ve masraf etkin yapmaktadır. Literatür taramasında elektromanyetik fırlatma sisteminin teknolojik gelişim tarihi derlendi. Taşınacak kütle, ivme, hız, fırlatıcı uzunluğu ve elektromanyetik fırlatma sisteminin çeşidi teknolojik gelişimin ana konuları oldu. Tek kademeli ve çok kademeli olmak üzere mini ölçekli iki elektromanyetik fırlatma sistemi tasarlandı, üreti...
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