Additive and intensive grinding effects on the synthesis of cordierite

Cordierite was mechanochemically synthesized by mixing proper amounts of kaolin, talc and Al(OH)3. Full factorial experiments were planned, conducted, and the results were analyzed by the use of statistical techniques in order to understand the effects of process variables on the amount of synthesized product. The powder products were analyzed by XRD, DTA, and SEM-EDS. As a result of the statistical analysis, temperature was found to be the most important factor. Based on XRD peak intensity measurements, the cordierite mixture was completely amorphized by grinding at 300 rpm for 60 min. Cordierite was successfully produced at temperatures as low as 1150 °C by using the mixture after intensive grinding. The combined effect of magnesium borate additive and grinding on cordierite synthesis was also studied. These factors successfully decreased the synthesis temperature down to 1000 °C.2002-IYTE-0

Horticultural Characteristics of Summer Apple Cultivars from Turkey

Early varieties with a short active vegetation period are not exposed to abiotic stress factors for instance drought, high temperature, etc., caused by global climate change, and biotic stress factors such as codling moth (Cydia pomonella) and apple scab (Venturia inequalis) that cause serious economic losses. Therefore, their places are extremely important regarding sustainable, economical and quality production. In this context, four early varieties of apple (‘Vista Bella’, ‘Summer Red’, ‘Williams Pride’ and ‘Jersey Mac’) grown in Eskisehir—Turkey where has continental climate were characterized in terms of horticultural characteristics. The difference observed in flowering and harvest times between years showed that average air temperatures are essential on phenological characteristics. Furthermore, high temperature accelerates development physiology of fruit. Major important characteristics, namely, fruit length, width, weight, soluble solid content, antioxidant activity, vitamin C and total phenolic content were found in the range of 39.19–50.88 mm, 51.48–60.81 mm, 80.59–86.16 g, 11.87–12.19%, 50.69–80.57%, 2.24–4.79 mg 100 mL−1 and 259.23–871.42 mg GAE (gallic acid equivalent) L−1, respectively. ‘Summer Red’ and ‘Williams Pride’ varieties were found to be good in terms of pomological characteristics, while ‘Vista Bella’ came to the fore with its chemical properties. On the other hand, ‘Jersey Mac’ has shown superior performance in terms of both pomological and chemical characteristics. Pomological characteristics are affected more by ecological differences, while chemical characteristics vary according to the changes in the pomological properties. Pomological characteristics were found to have a significant positive correlation with each other but negatively correlated with chemical characteristics

Hexa­kis­(thio­urea-κS)nickel(II) nitrate: a redetermination

A preliminary X-ray study of the title mol­ecular salt, [Ni(CH4N2S)6](NO3)2, has been reported twice previously, by Maďar [Acta Cryst. (1961), 14, 894] and Rodriguez, Cubero, Vega, Morente & Vazquez [Acta Cryst. (1961), 14, 1101], using film methods. We confirm the previous studies, but to modern standards of precision and with all H atoms located. The central Ni atom (site symmetry ) of the dication is octa­hedrally coordinated by six S-bound thio­urea mol­ecules. The crystal structure is stabilized by intra- and inter­molecular N—H⋯S and N—H⋯O hydrogen bonds

Alanya ilçesi (Antalya) katı atık depolama alanının jeoteknik incelemesi

TEZ5838Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2006.Kaynakça (s. 40-41) var.vii, 42, 20 s. : res., hrt. ; 29 cm.This study aims to make the evaluation of conformance for the disorganized depot area to be reorganized properly, on Mount Yumru of Alanya, Antalya. Having this as the main purpose, 20 wells have been drilled and lugeon tests have been experimented. Also RQD and discontinuity evaluations have been made upon these units. According to these studies, it has been specified that the depot area constitutes permeable units of discontinuity frames and cavernous spaces. No aquiferous unit nor groundwater have been detected at the depot area or nearby. Lab experiments have been made on the rock samples to determine the bearing ratio of dolomite limestones. Results have shown us that the bearing pressure ratio changes between 47,88 kg/cm2 and 37,27 kg/cm2. Examinations have finally shown us that the studied area is too permeable to acquire full tightness and the area is not fit for organized storage.Yapılan bu çalısma, Antalya ili Alanya ilçesi Yumru dagında düzensiz olarak kullanılan deponi alanının düzenli depolama açısından uygunluk degerlendirmesinin yapılmasını amaçlamaktadır. Bu amaç dogrultusunda 20 adet sondaj kuyusu açılmıs ve Lugeon deneyleri yapılmıstır. Ayrıca bu birimler üzerinde RQD ölçümleri yapılmıs ve süreksizlik ölçümleri alınmıstır. Bu çalısmalara göre deponi alanının süreksizlik yapıları ve karstik bosluklar içeren çok geçirimli birimden olustugu belirlenmistir. Deponi alanı ve yakın civarında akifer özellik gösterecek bir birim bulunmamakta ve yer altı suyu içermemektedir. Dolomitik kireçtaslarının tasıma gücünün belirlenmesi için kayaç numuneleri üzerinde laboratuar deneyleri yapılmıstır. Elde edilen sonuçlara göre birimin izin verilebilir tasıma basıncının 47,88-37,27 kg/cm2 arasında degistigi belirlenmistir. İncelemeler sonucunda geçirimliligin çok yüksek oldugu inceleme alanı için sızdırmazlıgın tam olarak saglanabilmesinin mümkün olmadıgı belirlenmis ve bu alanının düzenli depolama açısından uygun olmadıgı tespit edilmistir.""Yumru Mevkii -Alanya (Antalya) Alanya Belediyesi Kompost ve katı atık düzenli depolama tesisi mevzii imar planı"" ve ""Jeoloji haritası"" va

Thermodynamic analysis of solar assisted geothermal organic rankine cycle system in atmospheric conditions of Konya province

Bu çalışmada Konya ili atmosferik şartlarında güneş enerjisi destekli jeotermal kaynaklı Organik Rankine Çevrimi (ORÇ) sisteminin termodinamik analizi yapılmıştır. Sistemde iş akışkanı olarak R141b seçilmiştir. Jeotermal enerji kaynağı 50°C olarak belirlenmiştir. Sistem gündüz şartlarında güneş enerjisi ile desteklenmektedir. Birim jeotermal akışkan debisi (mj=1kg/sn) için sistemin elektrik üretimi, enerji ve ekserji verimleri saatlik, aylık ve yıllık peryotlar için belirlenmiştir. Sistem elemanlarının ekserji yıkım değerleri ve yüzdeleri yıllık verilere göre belirlenmiştir. Sistemden birim jeotermal akışkan debisi için yıllık elektrik üretimi 3711 kWh olarak hesaplanmıştır. Güneş enerjisi ve jeotermal enerjinin yıllık elektrik üretimine katkısı sırasıyla %5,3 ve %94,7 olarak belirlenmiştir. Sistemin enerji verimi saatlik, aylık ve yıllık peryotlar için %4,3 olarak belirlenmiştir. Sistemin yıllık ekserji verimi %6,1 olarak belirlenmiştir. Sistemin yıllık ekserji yıkım oranları güneş kolektörlerinde %60,2, kondenserde %16,3 evaporatörde %13,1, türbinde %11,3, ısı değiştiricide %0,6 ve çevrim pompasında %0,3 olarak elde edilmiştir.In this study, the thermodynamic analysis of the solar energy assisted geothermal Organic Rankine Cycle (ORC) system was made under the atmospheric conditions of Konya. R141b was considered as the work fluid in the system. The geothermal energy source is determined as 50°C. The system was supported by solar energy in daytime conditions. The energy production, first law and exergy efficiency of the system for unit geothermal fluid flow rate (mj=1kg/sec) were determined for hourly, monthly and annual periods. Exergy destruction values and percentages of the system elements were determined for the annual period. Annual electricity production was obtained 3711 kWh for unit geothermal fluid flow rate. The contribution of solar energy and geothermal energy to annual electricity generation has been determined as 5.3% and 94.7%, respectively. The first law efficiency of the system has been determined as 4.3% for daily, monthly and annual periods. The annual exergy efficiency of the system has been determined as 6.1%. The annual exergy destruction rates of the system were obtained as 60.2% in solar collectors, 16.3% in the condenser, 13.1% in the evaporator, 11.3% in the turbine, 0.6% in the heat exchanger and 0.3% in the cycle pump

Effects of boron addition and intensive grinding on synthesis of anorthite ceramics

Anorthite ceramics were synthesized starting from mixtures prepared by using mechanochemical methods with boron oxide addition. The raw materials used in this study were Sivas Kaolin, calcined alumina/Al(OH)3 and calcite. Statistical experimental design techniques (SED) were used in order to determine and analyze the more important process variables for synthesizing anorthite ceramics. Phase characterizations of synthesized powders were performed by XRD using Cu Kα radiation. Microstructural characterization was performed by SEM. The results of screening experimental design clarified that the temperature was the most important process variable. Second most important process variable was grinding speed of starting mixture which was followed by additive amount and additive type. The effect of both additive use and grinding on anorthite synthesis helped decrease the synthesis temperature down to 900 °C. © 2007 Elsevier Ltd and Techna Group S.r.l

Low temperature synthesis of spinel powders by mechanical grinding

Proceedings of the 8th Conference and Exhibition of the European Ceramic Society; Istanbul; Turkey; 29 June 2003 through 3 July 2003Low temperature synthesis of spinel powder via intense mechanical grinding was performed. A dramatic decrease in the synthesis temperatures of ground powders was achieved. We were able to produce partially crystallized spinel at room temperature via a 110 minute grinding. Characterization of the synthesized powders was performed using SEM, XRD and DTA. Each stage of synthesis was analyzed using these techniques. Mixtures of Mg(OH)2 and Al(OH) 3 were used for synthesis. Temperatures as low as 800°C were able to produce bumps in the XRD patterns of ground powders at the 2θ angles for spinel crystals

Sintering and microstructural investigation of gamma–alpha alumina powders

Sintering behaviors of commercially available alumina powders were investigated using constant-heating rate dilatometric experiments. Each powder had different proportion of alpha/gamma alumina. Densification behaviors of powders were studied up to 1600 °C with three different heating rates of 1, 3.3 and 6.6 °C/min. Compacts of different gamma content alumina powders exhibited systematic anomalous second peaks in the densification rate curves at certain heating rates and temperatures. At 3.3 °C/min heating rate experiments, densification curves of 10% gamma phase alumina powder compacts reached a plateau after 1450 °C, and did not increase any further at higher temperatures. This phenomenon was double checked to understand powder behavior during sintering. 10% gamma phase alumina powder compacts showed the highest density for each heating rate. It reached 94% theoretical density with 1 °C/min heating rate. But 20% gamma phase alumina powder compacts had the finest grain size of about 1.40 μm. Final density and porosity of compacts were also tested by image analysis and the results were coherent with Archimedes results

Horticultural Characteristics of Summer Apple Cultivars from Turkey

Early varieties with a short active vegetation period are not exposed to abiotic stress factors for instance drought, high temperature, etc., caused by global climate change, and biotic stress factors such as codling moth (Cydia pomonella) and apple scab (Venturia inequalis) that cause serious economic losses. Therefore, their places are extremely important regarding sustainable, economical and quality production. In this context, four early varieties of apple (‘Vista Bella’, ‘Summer Red’, ‘Williams Pride’ and ‘Jersey Mac’) grown in Eskisehir—Turkey where has continental climate were characterized in terms of horticultural characteristics. The difference observed in flowering and harvest times between years showed that average air temperatures are essential on phenological characteristics. Furthermore, high temperature accelerates development physiology of fruit. Major important characteristics, namely, fruit length, width, weight, soluble solid content, antioxidant activity, vitamin C and total phenolic content were found in the range of 39.19–50.88 mm, 51.48–60.81 mm, 80.59–86.16 g, 11.87–12.19%, 50.69–80.57%, 2.24–4.79 mg 100 mL−1 and 259.23–871.42 mg GAE (gallic acid equivalent) L−1, respectively. ‘Summer Red’ and ‘Williams Pride’ varieties were found to be good in terms of pomological characteristics, while ‘Vista Bella’ came to the fore with its chemical properties. On the other hand, ‘Jersey Mac’ has shown superior performance in terms of both pomological and chemical characteristics. Pomological characteristics are affected more by ecological differences, while chemical characteristics vary according to the changes in the pomological properties. Pomological characteristics were found to have a significant positive correlation with each other but negatively correlated with chemical characteristics

Energy storage and semiconducting properties of polyaniline/graphene oxide hybrid electrodes synthesized by one-pot electrochemical method

WOS:000701766500002Polyaniline/graphene oxide composites are produced by the one-pot electrochemical deposition method and are used as an electrode for supercapacitor energy storage. The electrochemical tests related to the energy storage performance of the PANI/GO electrodes at different mass loading of GO are successfully studied. The biggest specific capacitance for all of the electrodes is observed at a specific current of 0.3 A g−1. Pure PANI electrode has a specific capacitance of 158.0 F g−1, a specific energy of 18.2 W h kg−1, and a corresponding specific power of 118.8 W kg−1. After the loading of graphene oxide into PANI, the best specific capacitance measured at a current density of 0.3 A g−1 is 295.9 F g−1, and the corresponding specific energy and specific power are 34.0 Wh kg−1 and 126.9 W kg−1, respectively. The PANI/GO hybrid materials also exhibit a remarkably cycling stability with a capacitance retention range of 62.3%–83.7% after 5000 charge-discharge cycles. Charge transfer resistance of the PANI electrode desreases as GO loading increases. This means that electroactive surface area of the electrode increases due to the addition of GO into PANI. The enhancement in energy storage capability is supported by the increase in electroactive surface area. The high energy storage performance and easy production of PANI/GO materials make them promising electrodes for supercapacitor devices