5916 research outputs found
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MOF/COF hybrids as next generation materials for energy and biomedical applications
No full textThe rapid increase in the number and variety of metal organic frameworks (MOFs) and covalent organic frameworks (COFs) has led to groundbreaking applications in the field of materials science and engineering. New MOF/COF hybrids combine the outstanding features of MOF and COF structures, such as high crystallinities, large surface areas, high porosities, the ability to decorate the structures with functional groups, and improved chemical and mechanical stabilities. These new hybrid materials offer promising performances for a wide range of applications including catalysis, energy storage, gas separation, and nanomedicine. In this highlight, we discuss the recent advancements of MOF/COF hybrids as next generation materials for energy and biomedical applications with a special focus on the use of computational tools to address the opportunities and challenges of using MOF/COF hybrids for various applications.European Union’s Horizon 2020 ; European Research Counci
Influence of accelerometer type on uncertainties in recorded ground motions and seismic damage assessment
No full textStrong motion data recorded by strong-motion networks are essential for preventing and mitigating earthquake disasters, such as earthquake early warning and earthquake emergency responses, and the type of accelerometer can significantly influence the quality of recorded ground motions (GMs) and the subsequent usage. Different types of accelerometers vary significantly in both the price and the quality of collected data, because cheap accelerometers generate non-negligible self-noise and reduce the quality of the collected GMs. However, the effects of the accelerometer type and spatial density on the accuracy of GM-based seismic damage assessment are still unknown. The present study attempts to quantify these effects comprehensively at a regional scale. First, a method to simulate recorded data from different quality sensors is devised, using characteristics of existing low-, medium-, and high-quality accelerometers. These simulations use input data from either the Pacific Earthquake Engineering GM database or from a high-fidelity fault rupture and regional wave propagation simulation. Subsequently, the simulated sensor data are used to assess the seismic damage to typical buildings at a city scale. The results indicate that low-quality sensors found in most smartphones are currently insufficient for assessing seismic damage. Medium-quality accelerometers (MEMS-based instruments), on the other hand, can provide feasible solutions for cost-effective city-scale deployment and may offer deployment options that are superior to sensor networks with high-quality accelerometers.Shuimu Tsinghua Scholar Program ; Tencent Foundation ; Texas Advanced Computing Center ; Tsinghua University ; TÜBİTAK ; National Key Research and Development Program of Chin
Impact of a thermal medium on newly observed Zcs(3985) resonance and its b-partner
No full textMotivated by the very recent discovery of the strange hidden-charm exotic state Zcs(3985) by the BESIII Collaboration, we study the possible interpretation of this exotic state the both at T= 0 and T≠ 0. We analytically compute the mass and meson-current coupling constant of this resonance with spin-parity JP= 1 + at finite temperature approximation up to the sixth order of the thermal operator dimension including non-perturbative contributions. Extracting thermal mass and meson-current coupling constant sum rules, the modifications on properties of the Zcs(3985) state in hot medium are determined. As a by-product, the hadronic parameters of the bottom partner of Zcs(3985) is estimated as well. The search for temperature effects on the hadronic parameters of the hidden-charm meson Zcs(3985) and the bottom partner enable us to understand the phase transitions, chiral symmetry breaking, and the properties of hot-dense matter in QCD. Moreover, the full width of the resonance Zcs(3985) is calculated as (12.0±0.8)MeV using the strong decay in the tetraquark picture. Results for width and mass are in reasonable agreement with existing experimental data and results of other theoretical works. The information obtained about the parameters of the considered states is useful for experimental investigations of exotic mesons.Publisher versio
A 130 nm CMOS receiver for visible light communication
No full textVisible light communication (VLC) is an emerging technology that has been gaining attention over the last few years. Transmission of data at higher rates in a VLC system is mainly limited by the modulation bandwidth of the employed LED. To alleviate this limitation, equalization is frequently employed. This is usually achieved by either using discrete circuit elements or in digital form. In this paper, we present a power-efficient VLC receiver as a system-on-chip, implemented in 130 nm CMOS technology. The proposed receiver supports LEDs with different bandwidths thanks to the switchable equalizer. We tested the proposed receiver using phosphorescent white LEDs with different bandwidths on an experimental VLC link. For each tested LED, around 20 fold improvement in data rate was achieved compared to the original bandwidth of the LED. For the LED with a modulation bandwidth of 1.6 MHz, data rates of 32 Mbps and 50 Mbps at a BER of 102 were obtained at a distance of 2 meters without and with a blue filter, respectively
Sosyoekonomik durumun, anne psikopatolojisinin, yansıtıcı i̇şleyişin ve duygu sosyalleştirmenin erken çocukluk döneminde gözlenen davranış problemlerindeki rolü
No full textThe aim of the present study was to investigate the relationships between socio-economic status (SES), mother’s psychological symptoms, maternal reflective functioning, and mother’s use of emotional socialization practices and child behavioral problems during toddlerhood. The study also aimed to examine sex and age differences on the display of behavior problems of toddlers. Mothers who had children between the ages 1 to 3 and lived in different cities of Turkey (N = 534) participated in the study. The mothers were asked to complete a package of scales consisting of demographic form, Brief Symptom Inventory, Parental Reflective Functioning Questionnaire, Coping with Toddler Negative Emotions Scale, and Child Behavior Checklist. Based on the mothers’ reports, the results of hierarchical regression analyses showed that SES, maternal symptoms, and mother’s use of unsupportive emotion socialization behavior predicted toddler’s externalizing and internalizing behavior problems. Also, there was a significant age and sex differences on the child’ externalizing behavior problems with boys scoring higher than girls and older age children displaying more externalizing behavior problems than the younger ones. However, contrary to our expectations, mother’s supportive emotion socialization and reflective functioning didn’t predict child behavior problems. Overall, the present findings provide further support to family process model in predicting child behavior problems.TÜBİTAKPublisher versio
Decision model and application of electric vehicle charger installation to distribution transformers
No full textIt is very evident that the number of electric vehicles worldwide will increase and that the dominant mobility concept in the future will be at the center of EVs. As a requirement of e-mobility, EVs should be rechargeable anywhere and in any situation, and this will increase EV-based electrification. The effects of EV charging stations on the grid are very important in the increasing electricity demand level and the installation of EV charging stations on distribution transformers (DTs) should be balanced and should not have negative effects on the transformer. This paper aims to determine the number of EV charging stations to be loaded on distribution transformers in an optimized and safe manner. The data of 8361 distribution transformers in the Central Anatolian Region were collected and analyzed. Data verification was completed with data cleansing methods and an effective EV charging station installation modeling was developed. By modeling with three different risk levels, it is possible to determine which distribution transformer will be installed from four different EV charging socket types. The general situation of DTs in the region was determined with the pilot region application. Basic data can be revealed by modeling which region can be improved for the EV infrastructure going forward
Çelik kirişler için farklı endüstriyel intumesan boyaların yangından koruma performansları
No full textThis study covers comparison of fire protection performance efficiencies of two commercially available different intumescent coatings on two 1-meters steel beams which have S275 steel grade and UPN 200 steel sections for 2 hours by following ISO 834 fire curve in a furnace in Turkish Standards Institute (TSE) laboratory. Each beam was insulated with different industrial intumescent coatings to explore the efficiency of these intumescent coatings. Hence, all variables containing workmanship quality, period of application of intumescent coatings, steel grade, steel sections, furnace type, fire type and period of the experiment were kept constant except the type of intumescent coatings. First intumescent coating which is the Product A complies to BS 476-20,22 and EN 13381-8 and has an ISO Standards certificate. The Product B complies to ASTM UL-94 and EN 13381-8 and has a TSE certificate. 12 thermocouples were applied on each steel beams before the intumescent coatings performed to get temperature-time curves to determine the time to reach the critical temperatures of steel beams which were isolated. Fin EC software was used for the preliminary analysis to determine the critical temperatures and ABAQUS software was used to define the critical temperatures of each insulated steel beam and heat transfer analysis to compare with the temperature-time curves with experimental ones to have a better understanding of intumescent coating's thermal barrier duty in a case of ISO 834 fire type.Bu çalışma, ticari olan kullanılan iki farklı intumesan boyanın iki adet S275 çelik kaliteli ve UPN 200 kesit tipli 1'er metrelik çelik kirişe uygulanarak, Türkiye Standartları Enstitüsü'nün (TSE) yangın laboratuvarındaki fırında 2 saat süresince ISO 834 yangın tipine karşı yangına karşı koruma performanslarının verimliliğinin karşılaştırılmasını içermektedir. Her iki çelik kiriş, iki farklı ticari intumesan boya ile izole edilerek bu boyaların verimliliği açığa çıkartılmaya çalışılmıştır. İntumesan boya tipleri hariç olmak üzere uygulayıcı kalitesi, boyama süresi, çelik kalitesi, çelik kesiti, fırın tipi, yangın tipi ve deney süresi gibi tüm değişkenler sabit tutulmuştur. Product A diye adlandırdığımız birinci ürün ISO Standartlarına sahip ve BS 476-20,22 ile EN 13381-8'e göre uygunluk gösterecek şekilde test edilmiştir. Product B diye adlandırdığımız ikinci ürün ise TSE sertifikasına sahip ve ASTM UL-94 ve EN 13381-8 'e göre uygunluk göstermektedir. İntumesan boyaların kaplanmasından önce her kirişe 12 şer tane aynı lokasyonlarda olacak şekilde sıcaklık-zaman eğrileri elde ederek kritik sıcaklıkları belirleyebilmek amacıyla ısıölçerler sabitlenmiştir. Fin EC programıyla kritik sıcaklıkları belirlemek için ön analiz yapılmış olup, ABAQUS programıyla teorik olarak kritik sıcaklıklara ulaşma zamanı belirlenerek, elde edilen sıcaklık-zaman grafikleri karşılaştırılarak ve ısı analizi de yapılarak intumesan boyaların ISO 834 yangınına karşı termal bariyer görevi görerek yangından koruma performansları hakkında daha iyi bilgi sahibi olmaya çalışılmaktadır
Uzamsal korelasyonları kullanarak eşitsizlik (derinlik) görüntülerini sıkıştıran verimli bir algoritma ve onun düşük maliyetli donanım mimarısı
No full textThis thesis proposes a low-cost Disparity Map (DM) compression algorithm and its hardware architecture for high resolution and high frame rate applications, where limited computational capacity and power consumption make it a significant challenge to run these applications in real-time. The proposed algorithm uses spatial correlations between neighboring disparity values and has two variants. The first variant, Single Neighbor (SN), encodes the current disparity using its left neighbor, whereas the second variant, Multiple Neighbor (MN), benefits from left and upper neighbors. The performance of the proposed algorithm is evaluated on DMs that are obtained using the most common low-cost stereo matching techniques for state of- the-art benchmarks. When evaluating the performance of the proposed compression algorithm, a median filter is applied to smooth out the DMs. After the median filter, the proposed algorithm with respect to original DM sizes, obtains 48% and 56% savings in memory space on the average for its SN and MN variants, respectively. Transferring DMs to the memory within the System-on-Chip (SoC) and transmitting them between SoCs in a compressed format will reduce the memory bandwidth usage and save power. Implementation results show that the proposed architecture can support 1920x1080 resolution at 60 fps on a low-cost FPGA while consuming very low area and power.Bu tezde, Eşitsizlik (Derinlik) Görüntülerini (DM) sıkıştırmak için düşük maliyetli bir algoritmanın yanısıra, yüksek çözünürlük ve yüksek kare hızı gerektiren ugyulamalara uygun bir donanım mimarisi önerilmektedir. Özellikle bu uygulamaların gerçek zamanda çalıştırılabilmesi, hesaplama kapasitesi ve güç tüketimi açısından büyük bir zorluktur. Önerilen algoritma, komşu piksellerin arasındaki uzamsal korelasyonlarını kullanır ve iki varyantı vardır. Tek Komşu (SN), sol komşusunu kullanarak mevcut eşitsizlik değerini kodlarken, ikinci varyant, Çoklu Komşu (MN), sol ve üst komşulardan yararlanır. Önerilen algoritmanın performansı, son model DM veri setine bağlı bir şekilde, yaygın düşük maliyetli stereo eşleştirme teknikleri kullanılarak elde edilen DM'ler üzerinde değerlendirildi. Önerilen sıkıştırma algoritmasının performansını değerlendirirken, DM'leri aşırı gürültüden temizlemek için bir medyan filtresi uygulanır. Medyan filtresinden sonra önerilen algoritma, SN ve MN varyantları için sırasıyla ortalama olarak bellek alanında %48 ve %56 tasarruf elde etmektedir. DM'leri Yonga-üzeri-Sistem (SoC) içindeki belleğe aktarmak ve bunları SoC'ler arasında sıkıştırılmış bir biçimde iletmek, bellek bant genişliği kullanımını azaltacak ve güç tasarrufu sağlayacaktır
A fluid approximation for the single-leg fare allocation problem with nonhomogeneous poisson demand
No full textFare allocation for legs and O&D pairs plays a crucial role in airline revenue management. Despite a large number of dynamic pricing studies, there are only a few widely adopted studies in which assumptions affect most tactical decisions with potentially large impacts on airline profitability. These decisions involve approximating future pricing schemes, allocation of fare classes, and setting booking limits. We propose a fare allocation model for a single leg in the presence of a realistic nonhomogeneous Poisson demand with an increasing rate. We aim to compute when and how to markup the price for an airfare product (switch to an upper fare class) to maximize the expected revenue. We study a fluid approximation of the underlying stochastic problem considering independent demand from each customer segment and examine different properties that lead to several important insights. Finally, we propose a dynamic look-ahead pricing scheme to compare our fluid approximation results against the well-known EMSRb heuristic and a dynamic programming solution on randomly generated booking request data. Numerical examples illustrate the effectiveness of our proposed approach
