Stark effect, polarizability and electroabsorption in silicon nanocrystals

Demonstrating the quantum-confined Stark effect (QCSE) in silicon nanocrystals (NCs) embedded in oxide has been rather elusive, unlike the other materials. Here, the recent experimental data from ion-implanted Si NCs is unambiguously explained within the context of QCSE using an atomistic pseudopotential theory. This further reveals that the majority of the Stark shift comes from the valence states which undergo a level crossing that leads to a nonmonotonic radiative recombination behavior with respect to the applied field. The polarizability of embedded Si NCs including the excitonic effects is extracted over a diameter range of 2.5--6.5 nm, which displays a cubic scaling, $\alpha=c D^3$, with $c=2.436\times 10^{-11}$ C/(Vm), where $D$ is the NC diameter. Finally, based on intraband electroabsorption analysis, it is predicted that p-doped Si NCs will show substantial voltage tunability, whereas n-doped samples should be almost insensitive. Given the fact that bulk silicon lacks the linear electro-optic effect as being a centrosymmetric crystal, this may offer a viable alternative for electrical modulation using p-doped Si NCs.Comment: Published version, 7 pages, 7 figure

Tools for the Conceptual Design and Engineering Analysis of Micro Air Vehicles

Micro Air Vehicles (MAV) are a subset of Unmanned Aircraft (UAS) that are up to two orders of magnitude smaller than manned systems. Near-Earth environments, such as forests, caves, tunnels and urban structures make reconnaissance, surveillance and search-and-rescue missions difficult and dangerous to accomplish. Therefore, MAVs are considered ideal for these types of missions. However, the data using full size aircraft is inadequate to characterize miniature aircraft parameters due to the lower Reynolds numbers and low aspect ratio (LAR) wings and impact of wing-propeller interactions. The main objectives of this research were to: collect and synthesize the available data/tools; create a statistically integrated database/tool set of MAV designs for conceptual design trades; validate the tool set using published experimental data; synthesize and model a prototype design using conceptual and empirical analysis; highlight MAV-specific design criteria and identify gaps in existing data for later research. The following design tools have constituted the starting point for creating a demonstration tool-set for MAV design: Digital DATCOM (aerodynamics), Athena Vortex Lattice (AVL) (stability and control), QPROP (propeller, motor, and energy requirement), MATLAB (various applications), Microsoft Excel (power/battery modeling) and Phoenix Integration Model Center (MC) as the executive control program (integration, sizing and trade studies). Validation cases were completed for the current level of the single-prop, fixed-wing design tool. A coaxial MAV prototype was evaluated and some parametric studies were conducted for QPROP performance

Molekularno otkrivanje i genomska svojstva psećeg virusa Torque teno u Turskoj

Torque teno virus (TTV) was first detected in humans, and since then it has been reported in many host species, such as monkeys, cats, pigs, seagulls and dogs. The aim of this study was to investigate the presence of Torque teno canis virus (TTCaV) in shelter dogs housed in Sivas Municipal Animal Shelter, Turkey. Faecal specimens, including diarrheic and non-diarrheic (n=202), were collected from dogs of various age groups. In total, 32.18% (65/202) of samples were found positive for TTCaV. Out of the 65 positive samples, 34.64% (44/127) samples were from adult diarrheic dogs and 26.09% (6/23) belonged to diarrheic puppies. On the other hand, 28.84% (15/52) positive samples were detected from clinically healthy dogs. Eight sequences showed close homology among themselves, however, the sequences of two samples (CANEL130 and CANEL140) were genetically distinct from other published sequences. This is the first report on the detection of TTCaV in adult dogs and puppies in Turkey, and provides evidence that TTCaV cannot be considered as the sole cause of diarrhea.Virus Torque teno (TTV) otkriven je najprije u ljudi, no otada je zabilježen i u mnogim drugim domaćinima kao što su majmuni, mačke, svinje, galebovi i psi. Cilj ovoga rada bio je istražiti prisutnost psećeg virusa Torque teno (TTCaV) u pasa u azilu Sivas Municipal Animal Shelter u Turskoj. Uzorci izmeta (n = 202), uključujući one s proljevom i bez proljeva, prikupljeni su od pasa različitih dobnih skupina. Ukupno je 32,18 % (65/202) uzoraka bilo pozitivno na TTCaV. Od 65 pozitivnih uzoraka njih 34,64 % (44/127) potjecalo je od odraslih pasa s proljevom, a 26,09 % (6/23) od štenadi s proljevom. S druge strane, 28,84 % (15/52) pozitivnih uzoraka utvrđeno je u klinički zdravih pasa. Osam je sekvencija pokazalo međusobnu blisku srodnost, no sekvencije dvaju uzoraka (CANEL130 i CANEL140) genetski su se razlikovale od drugih sekvencija. Ovo je prvi nalaz TTCaV u odraslih pasa i štenadi u Turskoj i dokazuje da se TTCaV ne može smatrati jedinim uzročnikom proljeva

Urban water demand forecasting based on climatic change scenarios

Water resources projects, are designed to serve for many years to meet water needs. Therefore, the future water demand forecasting is of great importance for planning and management of water resources. In this study, a multi linear regression model is built to forecast urban water consumptions based a series of variables, namely the population served, monthly mean temperature and monthly total precipitation. Using the extended values of the variables up to the year 2100 based on climatic change scenarios, urban water demands are forecasted up to 2100

Comparison of thoracotomy and thoracoscopy in patients with esophageal atresia - tracheoesophageal fistula

Objective: The aim of this study was to compare the patients who underwent EA-TEF repair with both classical and thoracoscopic methods, and thus to reveal the advantages and disadvantages of both techniques. Materials and methods: In this study, the files of 45 patients who underwent surgery for EA-TEF at the Erciyes University Faculty of Medicine (EUFM) Pediatric Surgery Clinic between August 2005 and July 2012 were retrospectively examined. Patients were divided into two groups based on the surgical method applied. Results: A total of 45 patients who presented with EA-TEF and underwent surgical procedures were evaluated. Thirty-one (70%) patients underwent thoracotomy (Group I), and 14 (30%) patients underwent surgery using the thoracoscopic method (Group II). The average gestational age was 37.5 weeks, and the birth weight was 2600 grams. Nineteen (42%) of the patients were female, and 26 (58%) were male. Group I was 39 weeks and 38 weeks in Group II. There was no significant difference in gestational age between the two groups (p>0.05). There was no significant difference between the groups regarding accompanying system anomalies (p>0.05). The time to surgery for patients in both groups was 2 days (p>0.05). The operation time in Group I (95 minutes) was shorter than in Group II (105 minutes) (p<0.05). The time to start gavage feeding after surgery in Group II was shorter compared to Group I (p<0.05). No difference was detected between the groups concerning the time to start oral feeding (p>0.05). No difference was detected between the groups concerning the length of hospital stay (p>0.05). There was no significant difference between the groups regarding the rate of complications (p>0.05). No patient died during surgery. Eleven (35%) of the 31 patients in Group I and 2 (14%) of the 14 patients in Group II died between postoperative days 1 and 25. There was no difference in mortality rates between the groups (p>0.05). Conclusions: Postoperative complications were detected at similar rates in both groups

Sanat Tarihine Geçmiş Eserlerin, Günümüz Sanatsal Tasarımlarına Etkilerinin Pastiş ve Parodi Kavramları Çerçevesinde Değerlendirilmesi

Sanat tarihi incelendiğinde, insanların varoluşundan bu yana büyük bir etkileşim silsilesi gözlenmektedir. İnsanlık, kendinden önceki toplumları doğrudan ya da dolaylı yollarla kendine ya da kendi topluluklarına mal etmiştir. Antik dönemde üretilen sanat eserleri Rönesans dönemini, Rönesans döneminde üretilen sanat eserleri de kendinden sonraki dönemlerin sanat eserlerini ve sanatçılarını etkilemiştir. Günümüz sanatında, teknolojinin gelişmesi iletişimi daha da güçlü hale getirdi. Sanatsal tasarımların, imgelerin aynı anda dünyaya yayılması etkileşimi arttırdı, pastiş ve parodinin gelişmesine katkı sağladı. Pastiş (öykünme), sanat eserinin oluşum evresinde yer alan bir yöntem olarak adlandırılır. Postmodern dönemde yer alan bir diğer yöntemde Parodi (yansılama)’dır. Pastiş yoluyla üretilen eserler, sanatçıya saygı niteliğini taşırken, parodi yoluyla üretilen eserler alaycı ve mizah dolu bir tavır sergilemektedir. Sanatçıya ve sanat eserine saygıyı gösteren pastiş, kendinden anlamca zıt olan parodiyi doğurmuştur. Postmodern öğretinin belirleyici unsurlarından olan pastiş ve parodi bir form olarak düşünüldüğünde, sanat dallarında bir alıntılama yöntemi olarak kullanılmaktadır. Eseri üreten sanatçılar, kendilerinden sonraki sanatçılara esin kaynağı olmuş ve onlara bakış açısı kazandırmışlardır. Sanata yeni arayış ve yorumlar getirerek anlam/kavramlar kazandıran bu yöntemler, çoğunlukla postmodern dönemde karşımıza çıkmakta, yeniden üretilen eserleri anlamaya ve yorumlamaya olanak sağlamaktadır

Treatability of landfill leachate treatment in anaerobic fluidized bed reactors

Katı atık depolama alanı sızıntı suyunun kalitesi oldukça değişken olup birçok endüstriyel atıksuya göre daha geniş aralıkta bir kirlilik yüküne sahiptir. Bu çalışmada, İstanbul Avrupa yakası, Kemerburgaz (Odayeri) katı atık düzenli depolama alanı sızıntı sularının Anaerobik Akışkan Yataklı Reaktör’de (AAYR) arıtılabilirliği araştırılmıştır. Çalışmanın yapıldığı akışkan yataklı reaktörün çapı 10 cm, yüksekliği 165 cm, etkili hacmi 13 L’dir. Yatak malzemesi olarak 0.5 mm’lik filtre kumu kullanılmış ve sabit yatak yüksekliği 70 cm’dir. Organik Yükleme (OLR) sekiz kademede sırasıyla 2.5; 4.5; 8; 12; 18; 27; 37 ve 20 kgKOİ/m3-gün olarak yapılmıştır. Giderilen KOİ başına üretilen gaz miktarı parametresi izlenerek reaktör kontrol altında tutulmuştur. KOİ giderimi, birinci kademede %80’ler civarında iken, sonraki kademelerde %90’lar seviyesine ulaşmış ve sistem yaklaşık 6 haftada kararlı hale gelmiştir. Yükleme artırıldıkça biyogaz üretimi de artmıştır. Sekiz kademede gerçekleştirilen organik yüklemede biyogaz üretimleri, 14 - 203 L/gün arasında değişmiştir. Sistem her yükleme kademesinde kararlı hale ulaştığında, giderilen KOİ başına üretilen toplam gaz miktarı 0.51-0.53 L/gKOİgid.gün olarak elde edilmiştir. Yapılan ölçümlerde toplam gazdaki metan içeriği %75 olarak bulunmuştur. Reaktörün üç noktasından (30, 80 ve 110 cm) kum numuneleri alınarak biyofilm gelişimi izlenmiştir. Tutunmuş biyokütle konsantrasyonunun (Xatt) taban ve tepe noktaları arasındaki değer farkı %3 ile %38 arasında değişmiştir. Yaklaşık yedi ayda ortalama biyokütle konsantrasyonu 70.000 mgUAKMatt/L değerine erişmiştir. Anahtar Kelimeler: Sızıntı suyu, anaerobik arıtma, akışkan yataklı reaktör, biyogaz üretimi.The sanitary landfill method for ultimate disposal of municipal and industrial solid wastes is widely used in many countries around the world. The leachate generated from a landfill site containing organic, inorganic and heavy metal compounds, is a complex mixture with foul odour. The flow rate and composition of sanitary landfill leachate vary depending on the site, season and age of the landfill. Leachate from young landfill is usually high-strength wastewaters consisted of 10000 - 70000 mg/L COD, pH of 7-8 and several toxic/hazardous components. The main applicable methods for leachate treatment include biological, chemical and physical treatment processes. Many investigators have studied treatment of the sanitary landfill leachate using coagulation-flocculation, electro-Fenton method, Sequencing Batch Reactor (SBR), combined electro-Fenton oxidation and SBR, membrane processes Upflow Anaerobic Sludge Blanket (UASB) reactors and moving-bed biofilm process. The fixed film reactors such as biofilter and fluidized bed reveal a greater efficiency than the conventional systems. The advantage of fluidized bed processes is the accumulation of a large amount of biomass by natural attachment, including high volumetric flow rates, short retention times and good stability performance. The fluidized bed technology has been successfully applied for the treatment of industrial wastewaters, and also the removal of nitrate, phosphorus and refractory/toxic organic. The Anaerobic Fluidized Bed Reactors (AFBR) have many advantages over the aerobic treatment processes due to lower energy costs and low sludge production. These reactors have been operated with different wastewaters and a large range of organic loading rate values between 3-150 gCOD/L day. Anaerobic fluidized bed reactors have been applied to different wastewaters for various Volumetric  Loading Rates (VLR) ranging from a few kg COD/m3.d to as much as 150-180 kg COD/m3.d. Although anaerobic biological processes often present the most economical solutions for high strength wastewater treatment, Advanced Oxidation Processes (AOPs) provide an effective means of treating biorefractory compounds with efficient process control. In this study, treatability of leachate from Odayeri sanitary landfill located on the European part of Istanbul was investigated in an anaerobic fluidized bed reactor. The experiments have been performed in a pilot-scale fluidized bed reactor having an inner diameter of 10 cm, a height of 165 cm and an effective volume of 13 L. The reactor media was typical filter sand having an arithmetic mean diameter of 0.5 mm and a fixed bed height of 70 cm. The AFBR experiments were carried out by increasing the Organic Loading Rate (OLR) from 2.5 to 37 kg COD/m3.day in eight operating steps. During 270 days of the operation, the feed rate (Qf) and the Hydraulic Retention Time (HRT) were 13 L/d and 1 day, respectively. Ammonia removal efficiency appeared to be very low, however, ammonia inhibition did not occur during the study. COD removal increased from 80% to 90% with increasing organic loading rates and the AFBR attained steady state conditions with a COD removal of 90% after 6 weeks. The AFBR systems have the characteristics of three-phase fluidized bed reactors due to the biogas formation. Therefore, the classic solid?liquid fluidized bed can be obtained introducing a correction factor for the biogas effects. Biogas production in the AFBR continuously increased during the leachate treatment process. The biogas production rate (Qgas) (L/d) obtained as 14 L/d after 20 days of the operation, also increased with increasing the OLR and the influent COD.Good biogas production yield (Ygas ) was obtained as 0.51-0.53 L biogas per g CODrem with a methane (CH4) content of 75%. The attached biomass concentration (Xatt) amounted to about 90% of the total biomass concentration and showed an increase throughout the bed between the ranges 3-38%. The mean attached biomass concentration also increased up to 70000 mgVSSatt/L in the last two months. Keywords: Landfill leachate, anaerobic treatability, fluidized bed reactor, biogas production

Color removal from textile wastewater in modified fixed bed zeolite column reactor and regeneration of zeolite bed.

Bu çalışmada, sabit yataklı modifiye zeolit kolon reaktörde gerçek tekstil atıksularından zeolit ile adsorpsiyon uygulamasıyla renk giderimi araştırılmıştır. Doğal zeolitin adsorpsiyon kapasitesini arttırmak için zeolit yüzeyi, tipik kuaterner amin yüzey aktif madde hegzadesil trimetil amonyum bromür (HTAB) ile modifiye edilmiştir. Deneyler temel olarak modifikasyon, renk giderimi ve rejenerasyon olmak üzere üç ana kademeden oluşan toplam beş aşamada tamamlanmıştır. Kolondaki zeolit yatağın modifiye edilmesini takiben, tekstil atıksuyundan renk giderilmesi çalışılmıştır. Adsorpsiyon işleminden sonra doygun yatağın rejenerasyonu yapılmıştır. Rejenerasyonun etkinliğinin belirlenmesi amacıyla, zeolit yatak yeniden modifiye edilerek adsorpsiyon işlemi gerçekleştirilmiştir. Modifikasyon prosesinde kırılma eğrileri değişik HTAB konsantrasyonları için C/Co – süre ve BV (birim yatak hacmi başına arıtılan atıksu miktarı) olarak çizilmiştir. Renk gideriminde ise atıksuyun pik absorpsiyon değeri spektrofotometrede tespit edilmiş ve renk giderimi renk şiddeti olarak değerlendirilerek atıksulardan renk giderim kapasitesi, herhangi bir andaki absorbans değerinin başlangıç absorbans değerine oranı (bağıl renk şiddeti) olarak ifade edilmiştir. Modifikasyon, renk giderim ve rejenerasyon çalışmaları, 25 cm sabit yatak yüksekliğinde, 0.5–1 mm boyut aralığındaki 150 g zeolit ile 1 g/L HTAB konsantrasyonunda, 0.025 L/dk HTAB ve atıksu debilerinde yapılmıştır. Zeolitin adsorpsiyon kapasitesinin, atıksu debisine bağlı olarak belirli bir çalışma süresi sonunda azaldığı görülmüştür. 100 BV’ lik bir çalışma süresi verimli kabul edilirek 1 g/L HTAB modifikasyonu sonrası 0.025 L/dk atıksu debisi için renk giderimi başarılı olmuştur. Rejenerasyon çalışması pH 12 ve 60 oC’da gerçekleştirilmiştir. Doğal ve rejenere edilen zeolit için kırılma noktaları sırasıyla 930 ve 390 dakikada 132 BV ile 55 BV olarak gerçekleşmiştir. Anahtar Kelimeler: Adsorpsiyon, modifikasyon, rejenerasyon, renk giderimi, tekstil atıksuyu, zeolit.Textile industries consume large amounts of water and chemicals for dyeing processes and also dye wastewaters usually consist of a number of contaminants including acids, bases, dissolved solids, toxic compounds, and color. Reactive dyes are extensively used in textile dyeing processes, but about 20 to 40 % of these dyes remain in the effluents. The reactive (water-soluble) dyes cannot be easily removed by chemical coagulation/ flocculation because they strongly resist to biodegradation in an aerobic environment. Removal of reactive dyes from textile wastewater is considered as an important application of the adsorption process using low-cost adsorbents such as fly ash, chitosan, natural minerals against expensive adsorbents like activated carbon and polymer resins. The presence of 50 billion tons of natural zeolites of high quality, mainly those of clinoptilolite in Turkey, created an impetus for the utilization of clinoptilolite in wastewater treatment as a low cost adsorption material. In this study, color removal from real textile wastewater, which contains reactive dyes in a fixed bed column reactor, was investigated. In the studies, zeolites from Manisa-Gördes Region was used as a low cost adsorption material Adsorption of reactive dyes from the wastewater collected from a textile industry dye bath house effluent was researched using natural zeolite. The aim of this study was to investigate zeolites applicability to textile effluents for the removal of color, which contains reactive dyes in the fixed bed reactor and regenetability. The reactive dyes have negative sulfonate groups, which are repelled by the negatively charged zeolite surface. This induces a relatively low adsorption capacity for natural zeolite. For this reason, in order to increase the adsorption capacity, the surface of zeolite was modified with a typical quaternary amine surfactant hexadecyl trimethylammonium bromide (HTAB). In this respect, adsorption studies were carried out using modified zeolite in the fixed bed reactor and color removal performance of real textile wastewater was investigated. A series of tests were conducted by three stages as modification, color removal and regeneration. Each run consisted of modifying zeolite with HTAB in the column followed by removal of color from the real textile wastewater in the modified zeolite bed. Afterwards regeneration of modified zeolite column loaded with color was studied. At the end, in order to see the effect of regeneration on color removal, zeolite column once more modified. Finally, the real textile wastewater was given to modified zeolite column. Breakthrough curves for modification process were constructed under different conditions by plotting normalized effluent concentrations (C/Co) versus time (minute) or bed volumes (BV). Modification, color removal and regeneration studies were conducted by 1g/L HTAB concentrations a constant HTAB feeding flowrate of 0.025 l/min. and at a constant bed height of 25 cm (150 g of zeolite). Dimension of zeolite was 0.5-1 mm. and wastewater feeding flowrate was 0.025 l/min. Samples were taken every 30 minutes and analyzed using a visible spectrophotometer in 448 nm. In modification process, HTAB solution was pumped to the bottom of the column on the contrary of color removal process.  In color removal studies, at a C/Co value of 0.1, the bed volume (BV) reached approximately 132 after 930 minutes running period in the modified fixed bed column. Empty bed contact time (EBCT) found to be 7 min. The results were successful for color removal as above the 100 BV at a C/Co value of 0.1 was accepted. Regeneration studies were performed at the condition of 60 oC at pH 12. The regeneration solution prepared as 10.5 l with 30 g/L NaCl solution and 3 g/L NaOH. The regeneration solution was pumped to the top of the bed using a pump that maintained both mixing and expansion of the bed. Thus, the flow in the bed accelerated, the desorption of color from clinoptilolite particles. In second modification after regeneration process, the zeolite column was needed less HTAB quantity comparing the first one. In color removal studies after regeneration process at a C/Co value of 0.1, BV reached approximately 55 after a 390 min. running period. Experimental results indicated that modification of zeolite column with the flowrate of 0.025 l/min and 1 g/l HTAB dosage was successful for color removal. The modified column showed a good performance by comparing the regenerated column for the color removal from the real textile wastewater. As a result, the information obtained from the present research will be applied to remove color from the textile industry effluents. Keywords: Adsorption, color removal, modification, regeneration, textile wastewater, zeolite

H1N1 virüs enfeksiyon nedeniyle meydana gelen myokardit

A 25-year-old male patient, applied to emergency department with complaints of fever lasting for 3 days, non-productive cough and tachycardia. Troponin I level was 18 ng/ml. The patient had no previously known disease and was hospitalized in coronary intensive care unit. We presented a case of acute myopericarditis occurred after an acute influenza infection, caused by H1N1 virus that recently led to pandemics worldwide