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Solid-Liquid Phase Equilibrium: Alkane Systems for Low-Temperature Energy Storage
No full textThe thermal characterization of two binary systems of n-alkanes that can be used as Phase Change Materials (PCMs) for thermal energy storage at low temperatures is reported in this work. The construction of the solid-liquid binary phase diagrams was achieved using differential scanning calorimetry (DSC) and Raman spectroscopy. The solidus and liquidus equilibrium temperatures were determined using DSC for thirty-nine different samples, three for the pure n-alkanes and the remaining for binary mixtures at selected molar compositions and used to acquire the corresponding solid-liquid phase diagrams. The two binary systems of n-octane/n-decane (C8/C10) and n-decane/n-dodecane (C10/C12) are characterized by a eutectic behavior at low temperatures. The eutectic temperature for the system C8/C10 was found at 211.95 K and the eutectic composition appeared at the molar fraction xoctane = 0.87. For the system C10/C12, the eutectic temperature was found at 237.85 K, and the eutectic composition appeared for the molar fraction xdecane = 0.78. This work aims to fulfill the lack of available data in the existing literature, considering the potential application of these systems for low-temperature thermal energy storage. Raman spectroscopy was used to complement the DSC data for the construction of the solid-liquid phase equilibrium diagrams, enabling the identification of the solid and liquid phases of the system. Additionally, the liquidus curve of the phase diagram was successfully described using a modified freezing point depression curve as fitting equation, the absolute root mean square deviation for the data correlation of the C8/C10 and C10/C12 systems being 2.56 K and 1.22 K, respectively. Ultimately, the fitting procedure also enabled a good prediction of the eutectic point for both studied systems.Fundacao para a Ciencia e a Tecnologia (FCT
16. Ulusal Okul Öncesi Öğretmenliği Öğrenci Kongresi: Cumhuriyetin 100. Yılında Erken Çocukluk Eğitimi
No full text▪️ Kongre, ‘Cumhuriyetin 100. Yılında Erken Çocukluk Eğitimi’ ana teması ile 9-11 Kasım 2023 tarihinde İstanbul Kültür Üniversitesi Ataköy Kampüsünde gerçekleştirilmiştir
Neurophysiological and Biosignal Data for Investigating Occupational Mental Fatigue: MEFAR Dataset
No full textThe prevalence of mental fatigue is a noteworthy phenomenon that can affect individuals across diverse professions and working routines. This paper provides a comprehensive dataset of physiological signals obtained from 23 participants during their professional work and questionnaires to analyze mental fatigue. The questionnaires included demographic information and Chalder Fatigue Scale scores indicating mental and physical fatigue. Both physiological signal measurements and the Chalder Fatigue Scale were performed in two sessions, morning and evening. The present dataset encompasses diverse physiological signals, including electroencephalogram (EEG), blood volume pulse (BVP), electrodermal activity (EDA), heart rate (HR), skin temperature (TEMP), and 3-axis accelerometer (ACC) data. The NeuroSky MindWave EEG device was used for brain signals, and the Empatica E4 smart wristband was used for other signals. Measurements were carried out on individuals from four different occupational groups, such as academicians, technicians, computer engineers, and kitchen workers. The provision of comprehensive metadata supplements the dataset, thereby promoting inquiries about the neurophysiological concomitants of mental fatigue, autonomic activity patterns, and the repercussions of a cognitive burden on human proficiency in actual workplace settings. The accessibility of the aforementioned dataset serves to facilitate progress in the field of mental fatigue research while also laying the groundwork for the creation of customized fatigue evaluation techniques and interventions in diverse professional domains.Qatar National Research Fund (QNRF)
Graphene-Assisted Chemical Stabilization of Liquid Metal Nano Droplets for Liquid Metal Based Energy Storage
No full textEnergy storage devices with liquid-metal electrodes have attracted interest in recent years due to their potential for mechanical resilience, self-healing, dendrite-free operation, and fast reaction kinetics. Gallium alloys like Eutectic Gallium Indium (EGaIn) are appealing due to their low melting point and high theoretical specific capacity. However, EGaIn electrodes are unstable in highly alkaline electrolytes due to Gallium oxide dissolution. In this letter, this bottleneck is addressed by introducing chemically stable films in which nanoscale droplets of EGaIn are coated with trace amounts of graphene oxide (GO). It is demonstrated that a GO to EGaIn weight ratio as low as 0.01 provides enough protection for a thin film formed by GO@EGaIn nanocomposite against significantly acidic or alkaline environments (pH 1-14). It is shown that GO coating significantly enhances the surface stability in such environments, thus improving the energy storage capacity by over 10x. Microstructural analysis confirms GO@EGaIn composite stability and enhanced electrochemical performance. Utilizing this, a thin-film supercapacitor is fabricated. Results indicate that when coating the EGaIn with GO to EGaIn ratio of 0.001, the areal capacitance improves by 10 times, reaching 20.02 mF cm(-2). This breakthrough paves the way for advanced liquid metal-based thin-film electrodes, promising significant improvements in energy storage applications.European Research Council (ERC)
European Union under a European Research Council
SMART Display project
European Regional Development Fund, through Portuga
q-Analog of Prestarlike Functions
No full textWe introduce a class Rαq of q-prestarlike functions of order α by using q-difference operator. We obtain necessary and sufficient conditions involving convolution for functions to be in the class Rαq. We prove that the well-known class of analytic prestarlike functions, Rα, is properly contained in Rαq. Apart from finding bounds on some initial coefficients of functions in the class Rαq, we also investigate some convolution properties of functions in the class Rαq. The results of the present manuscript essentially generalize some well-known results in the literature. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024
The Reflections of Industry 4.0 in Logistics: A Case Study on Logistics 4.0 Applications
No full textEndüstri 4.0, sanayi sektöründe önemli kırılma noktalarından birini oluşturan büyük bir dönüşüm sürecidir ve otomasyon sistemleri, veri yönetimi ile üretim teknolojilerini kapsayan bir platform, sistemler seti veya toplu bir terim olarak tanımlanmaktadır. Endüstri 4.0, diğer bir deyişle Dördüncü Sanayi Devrimi, üretim süreçlerini, iş modellerini, çeşitli sektörleri etkilediği gibi yaşanan dönüşümün lojistik sektöründeki yansımaları sonucu ortaya çıkan anlayış, Lojistik 4.0 olarak adlandırılmıştır. Lojistik 4.0'ın gelişmesinin nedenleri sadece teknolojik gelişmeler değil aynı zamanda e-lojistikte öngörülemeyen artış, uluslararası ticaretin inanılmaz gelişimi ve e-ticaretin yaygınlaşmasıdır. Bu araştırmada Türkiyedeki lojistik firmaları arasında Lojistik 4.0 algısını, hangi aşamada olduğunu, konuyla ilgili farkındalık düzeyini, bu konudaki önemli hususları ve başarı faktörlerini ortaya koymak amacıyla Lojistik 4.0 yaklaşımı ile iş süreçlerini yöneten bir lojistik şirketinde keşifsel ve tanımsal yöntemle bir örnek olay incelemesi gerçekleştirilmiştir. Yapılan derinlemesine görüşme kayıtları MAXQDA 2020 programı ile analiz edilerek veriler, arşiv kayıtları ve literatür ile karşılaştırılmıştır. Çalışmanın bulguları, lojistik şirketlerinin Lojistik 4.0 konusunda bilinçlenmeye başladığını, bu anlamda müşteri odağında teknolojik dönüşüm için çalışmalar yapıldığını, Ar-Ge merkezleri kurmaya başladıklarını ve teknolojik adaptasyon eğitimlerinin ne kadar önemli olduğunu göstermektedir. Sonuçların ilgili literatüre katkı sağlamasının yanı sıra lojistik firmalarına, Lojistik 4.0'a geçiş için fikir vermesi hedeflenmektedir
A Study on Harmonic Functions
No full textThe class of functions that have bounded boundary rotation and bounded radius rotation are the generalization of the convex and the starlike functions, respectively. The concept of such functions was introduced by LOWNER [1]. But he did not use the present terminology. It was PAATERO [2,3] who systematically developed their properties and made an exhaustive study of the class of functions that have bounded boundary rotation. We will examine in this paper, the subclass of S-H H that is related to the class of functions that have bounded radius rotation
Yalın Tekniklerin İnşaat Projeleri Performansına Etkisinin Değerlendirilmesi
No full textYüksek lisans tezi.Inefficiency and waste permeate the construction industry, manifesting as extended timelines, inflated costs, and suboptimal resource utilization. Lean construction principles, however, offer a promising paradigm shift, enabling process streamlining and enhanced productivity. This research delves into a crucial question: to what extent can lean tools demonstrably improve construction efficiency, productivity, and performance compared to traditional methods? By adopting a rigorous simulation modeling approach, this study utilizes Discrete Event Simulation Approach to develop comprehensive models encompassing both baseline (conventional) and lean scenarios. By meticulously comparing these models, statistically significant insights were generated into the effectiveness of integrating lean techniques. The findings provide compelling evidence for the transformative power of Lean in improving project outcomes. Applying key principles like value specification, value stream mapping, value flow, pull production, and continuous improvement resulted in significant performance gains, while optimizing process and operational aspects further reduced project total time, solidifying the benefits of a leaner approach. Lean models demonstrated a 7.79% increase in process efficiency and a 30.29% reduction in cycle time for the retaining wall construction process, Moreover, the research transcends mere potential demonstration by quantifying the measurable impact of implementing specific lean tools, providing construction practitioners with clear evidence of their effectiveness, and developing practical guidelines for seamlessly integrating lean thinking into established management approaches, bridging the gap between theory and practice
KZPY'de Alternatif Tampon Boyutlandırma Yaklaşımları: Filistin'de Bir Vaka Çalışması
No full textYüksek lisans tezi.The implementation of project management methodologies is pivotal in achieving success in an increasingly complex and globally connected world. The widely used project scheduling method have been the Critical Path Method (CPM) until Critical Chain Project Management (CCPM) is introduced in 1997. Although CPM still dominates the scheduling approach in practice, CCPM is also continuously adopted to scheduling management of especially for resource constrained projects. On the other hand, finding the optimum buffer size introduced in CCPM approach is still a big challenge and studies on this area are still quite scarce. With this motivation, this thesis study is initiated to explore the adoption of CCPM principles to a resource-intensive mall project case in Palestine. Moreover, four different buffer sizing approaches proposed in the literature such as; Square Root of Sum of the Squares (SSQ), Adaptive Procedure with Density (APD), Adaptive Procedure with Resource Tightness (APRT) and Relative dispersion (RD) are studied and their performance are compared for their applicability for the selected case. The results revealed that the best option for project buffer size is obtained by applying APD Method; the duration to complete the project is computed as 555 which is 114 days (17%) less than CPM approach (with leveled resources). The study and the findings, underscores the importance of adopting appropriate buffer size considering the project characteristics in order to improve CCPM practices
Istanbul University rare works library poetry magazine no. TY 5481: Classification of the review text according to MESTAP
No full textYüksek lisans tezi.Mecmualar XIV. yüzyıldan bugüne birçok tür ve şekli içinde barındıran derleme eserlerdir. Muhteva yönünden de farklı alanlarda yazılıp derlenmiştir. Mecmualar ortaya çıkışından bugüne dek şairlerin not defterleri olarak da görülebilmektedir. Mecmualar yazıldığı dönemin şiir zevkini yansıtması açısından da çağına tanıklık eden önemli eserlerdir. Aynı zamanda mecmualar sayesinde tabiri câizse kıyıda köşede kalmış, tanınmayan yahut keşfedilmemiş ve divanı olmayan şairlerin de şiirlerini görme, tanıma, keşfetme ve bilime kazandırma şansı bulmaktayız. Bu çalışmamız İstanbul Üniversitesi Nadir Eserler Kütüphanesi TY05481 Numaralı Şiir Mecmuasının tavsifi, transkripsiyonlu metni, incelemesi ve MESTAP'a göre tasnifinden oluşmaktadır. Tezimize konu olan mecmua 81 varaktan müteşekkildir. Mecmuada 14. yüzyıldan 19. yüzyıla dek ekseriyetle halk şairleri ve şiirleri bulunmakla birlikte divan şiirlerine de yer verilmiştir. Mecmuada 78 şaire ait 209 şiir bulunmaktadır. En çok kullanılan nazım şekli müfreddir. Mecmuanın mürettibi belli değildir. Mecmua şair ve şiir bakımından da zengin bir içeriğe sahiptir. Mecmuada gazel, koşma, türkü gibi nazım şekillerinin yanında hammamiye gibi türler de bulunmaktadır. Ayrıca mecmuada bazı şairlerin divanlarında yer almayan şiirlerin de bulunması mecmuanın önemini ortaya koyan hususlardandır