Recent advances in hydrothermal carbonisation:from tailored carbon materials and biochemicals to applications and bioenergy

Introduced in the literature in 1913 by Bergius, who at the time was studying biomass coalification, hydrothermal carbonisation, as many other technologies based on renewables, was forgotten during the "industrial revolution". It was rediscovered back in 2005, on the one hand, to follow the trend set by Bergius of biomass to coal conversion for decentralised energy generation, and on the other hand as a novel green method to prepare advanced carbon materials and chemicals from biomass in water, at mild temperature, for energy storage and conversion and environmental protection. In this review, we will present an overview on the latest trends in hydrothermal carbonisation including biomass to bioenergy conversion, upgrading of hydrothermal carbons to fuels over heterogeneous catalysts, advanced carbon materials and their applications in batteries, electrocatalysis and heterogeneous catalysis and finally an analysis of the chemicals in the liquid phase as well as a new family of fluorescent nanomaterials formed at the interface between the liquid and solid phases, known as hydrothermal carbon nanodots

Artık eyleyicili küçük uydularda eyleyici arızalarına karşı kontrol dağıtımı.

In this thesis, design and analyses of honeycomb structures are investigated. Primary goal is to develop an equivalent orthotropic material model that is a good substitute for the actual honeycomb core. By replacing the actual honeycomb structure with the orthotropic model, during the finite element analyses, substantial advantages can be obtained with regard to ease of modeling and model modification, solution time and hardware resources . To figure out the best equivalent model among the approximate analytical models that can be found in the literature, a comparison is made. First sandwich beams with four different honeycomb cores are modeled in detail and these are accepted as reference models. Then a set of equivalent models with the same dimensions is generated. The material properties of the equivalent models are taken from different studies performed in the literature. Both models are analyzed under the same loading and the boundary conditions. In finite element analyses, ANSYS finite element program is used. The results are compared to find out the best performing equivalent model. After three major analyses loops, decision on the equivalent model is made. The differences between the total reaction forces calculated by the equivalent model and the actual honeycomb model are all found to be within 10%. The equivalent model gives stress results at the macro-scale, and the local stresses and the strains can not be determined. Therefore it is deemed that for stress analysis, equivalent model can be used during the preliminary design phase. However, the equivalent model can be used reliably for deflection analysis, modal analysis, stiffness determination and aero-elastic analysis.M.S. - Master of Scienc

Yeni asır ve anadolu gazetelerinde İzmir (1929-1939)

Türkiye’nin bugün üçüncü büyük şehri olan İzmir, Ege Bölgesi’nde yolların kesiştiği bir noktada bulunması dolayısıyla yüzyıllar boyunca önemli ticaret ve kültür merkezlerinden biri olmuş, çağlar boyunca önemini kaybetmemiştir. İzmir, iklimi, limanı ve geniş verimli topraklarıyla ayrı bir öneme sahiptir. Bünyesinde barındırdığı bütün bu özellikler nedeniyle sayısız istilalara uğramış, ancak Türkler buradaki varlıklarını koruyabilmişlerdir. İzmir, I. Dünya Savaşı’ndan sonra 18 Ocak 1919 tarihinde gerçekleşen Paris Barış Konferansında alınan karar üzerine 15 Mayıs 1919’da Yunanistan tarafından işgale uğramıştır. Bu işgal, halkın büyük direnci ve Mustafa Kemal Atatürk’ün engin askerlik ve liderlik yeteneği sayesinde 9 Eylül 1922 tarihinde son bulmuş, Türkler Kurtuluş Savaşı’ndan zaferle çıkmış, İzmir’deki Yunan istilası sonlanmıştır. İzmir’in 9 Eylül 1922 yılında işgalden kurtuluşundan hemen sonra 13 Eylül 1922’de İzmir’de büyük bir yangın baş göstermiş, yangın İzmir’in büyük bir kısmının tahrip olmasına neden olmuştur. Tez konum içerisinde yer alan 1929-1939 arası dönemde İzmir’de yangın alanından kurtulmak için çözüm yolları aranmıştır. 1929-1939 yılları arasında Türkiye, bir yandan 1929 dünya iktisadi buhranının etkilerini en aza indirmeye çalışmış, diğer yandan bu dönem içerisinde dünyada baş gösteren siyasi gerginlik, Türkiye’nin içe kapalı bir ekonomi uygulamasına neden olmuştur. 1929-1939 yılları arasında İzmir, Türkiye’nin bu dönemdeki politikasından ekonomik, siyasal, sosyal, idari, sağlık ve eğitim vb. alanlarda etkilenmiştir. Buna rağmen İzmir’de imar hareketleri ve modernleşme hız kazanmış, İzmir, bugünkü görüntüsüne büyük oranda kavuşmuştur. ABSTRACT İzmir, the third biggest city in Turkey today, has been one of the important commercial and cultural centres for centuries thanks to its location in the junction of highways in the Aegean Region, and has kept its prominence for ages. İzmir is of great importance regarding its climate, harbour and wide fertile land. The city was invaded innumerable times due to these properties it bore, however, Turks have managed to maintain their existence here. After World War I, İzmir was invaded by Greece on 15th May 1919, based on the arbitrament made in the Paris Peace Conference. This invasion was overcome on 9th September 1922 thanks to the great public resistance of Mustafa Kemal Atatürk’s profound military and leading skills. Turks won the War of Independence and the Greek invasion in İzmir ended. Just after İzmir’s salvation from the invasion on 9 September 1922, a great fire burst in the city on 13 September 1922 and this fire caused destruction of great part of the city. In the period between 1929-1939, which my thesis covers, solutions were sought to restore the burnt area. Between the years 1929 – 1939, Turkey both struggled to minimize the impacts of the Great Depression in 1929 and political occurring this period during these years caused Turkey to apply a closed economy. During 1929 – 1939 years, İzmir was affected by Turkey’s policy in the fields of economy, politics, social, administrative, health, education etc. Nevertheless, the improvement and modernization in İzmir gain acceleration and İzmir greatly attained its current appearance

Synthesis and Characterization of Carbonaceous Materials from Saccharides (Glucose and Lactose) and Two Waste Biomasses by Hydrothermal Carbonization

Carbonaceous particles are synthesized under hydrothermal conditions using two waste biomasses (olive oil waste and hazel nutshell) and saccharides (glucose and lactose). A stainless steel autoclave with 75 mL of capacity was used to apply the hydrothermal carbonization (HTC) process to the starting materials stated above. In the experiments, 2.5 g of sample dispersed in 50 mL of deionized water is subjected to HTC at 180 °C for 4 h. H/C and O/C ratios for the chars were found to be more similar to the lignite than those of the starting materials. The heating values for the chars were found to be higher as compared to that of the feedstocks. FTIR investigations of the chars reveal that biochars of saccharides have different chemical structures compared with glucose and lactose, while biochars of waste biomasses are similar chemical nature with their starting materials. Hydroxymethylfurfural (HMF), phenol, acids, and aldehyde contents of aqueous phases were also determined. Solid-state ¹³C CP/MAS NMR analysis of the chars gave hints about the formation mechanism of sphere-structured biochars. Two different formation mechanisms for the biochars of waste biomasses and saccharides were proposed according to solid-state ¹³C CP/MAS NMR analysis results. The structure of biochar obtained from glucose and lactose involved furanic chains, while the biochars from olive oil waste and hazel nutshell have mainly aromatic structure

Removal of heavy metals from water using engineered hydrochar:Kinetics and mechanistic approach

The isotherm, kinetics, and thermodynamics parameters, and mechanisms involved in the adsorption of Pb2+ and Cu2+ ions from an aqueous solution using engineered hydrochar were investigated. The hydrochar was produced through catalytic hydrothermal carbonization of rice straw at 200 °C with (engineered hydrochar) and without (hydrochar) FeCl3 (1.2 %) as iron catalyst which has been reported to have the ability to enhance surface properties. Batch experiments were conducted to examine the effect of sorbent dosage, pH, and initial metal ion concentration on the adsorptive performance. The results obtained revealed that the addition of iron catalyst increased the surface functional groups, and exhibit better adsorptive performance compared to non-treated hydrochar. The adsorptive performance of engineered hydrochar was higher for Pb2+ compared to Cu2+, which can be explained by surface complexation, cationic- π interaction, and mass diffusion process with the initial removal performance limited by mass transfer process. The Langmuir isotherm model gave the best fit for the adsorption of both metals compared to the other models tested. The adsorption kinetics followed the Lagergren's pseudo-second order model. Thermodynamic parameters revealed that Pb2+ and Cu2+ adsorption by engineered hydrochar is a spontaneous and endothermic process. Moreover, this study created new knowledge by providing an in-depth understanding of the effect of iron catalyst on the functional properties of engineered hydrochar and its adsorption mechanisms. Research on the use of catalysts in engineered hydrochar for pollutant removal is very limited. In addition, the study outcomes would contribute to the production of highly efficient magnetic hydrochars.</p