IYTE GCRIS Database (Izmir Institute of Technology)
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Experimental Investigation of Zinc Ferrite/Insulation Oil Nanofluid Natural Convection Heat Transfer, Ac Dielectric Breakdown Voltage, and Thermophysical Properties
No full textImproving the thermal and dielectric properties of insulation oil (INO) with nanoadditives is an important challenge, and achieving dispersion stability in these nanofluids is quite challenging, necessitating further investigation. The main goal of this study is the synthesis and use of the hydrophobicity of zinc ferrite (ZnFe2O4) nanoparticles, which can improve both the thermal and dielectric properties of the INO. This oil is made from distillate (petroleum), including severely hydrotreated light naphthenic oil (75-85%) and severely hydrotreated light paraffinic oil (15-25%). A comprehensive investigation was carried out, involving the creation of nanofluids with ZnFe2O4 nanoparticles at various concentrations, and employing various characterization methods such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR), scanning electron microscopy, energy dispersive X-ray (EDX), zeta potential analysis, and dynamic light scattering (DLS). The KD2 Pro thermal analyzer was used to investigate the thermal characteristics, including the thermal conductivity coefficient (TCC) and volumetric heat capacity (VHC). Under free convection conditions, the free convection heat transfer coefficient (FCHTC) and Nusselt numbers (Nu) were evaluated, revealing enhancements ranging from 14.15 to 11.7%. Furthermore, the most significant improvement observed in the AC Breakdown voltage (BDV) for nanofluids containing 0.1 wt% of ZnFe2O4 amounted to 17.3%. The most significant finding of this study is the improvement in the heat transfer performance, AC BDV, and stability of the nanofluids
Olay Sıra Çizgeleri için Alana Özgü Bir Dil
No full textYazılımın kalitesi, güvenilir ve hatasız yazılım çözümleri sunabilmek için ulaşılması gereken temel parametrelerden biridir. Sıklıkla model tabanlı testlerle kendini gösteren sistematik test yaklaşımı, yazılım kalitesini artırmak için kullanılan bir yöntemdir. Model tabanlı test yaklaşımına örnek olarak Olay Sıra Çizgeleri (OSÇ) verilebilir. Alana özel dil (AÖD), sınırlı bir alanda geliştirim sürecinde önemli avantajlar sağlayan bildirimsel bir dildir. Bu araştırma karar tablosuyla güçlendirilmiş hiyerarşik OSÇ tasarlama ve görselleştirme için OSÇ-AÖD adı verilen alana özgü bir dil geliştirmeye odaklanmaktadır. Değerlendirme amacıyla bir odak grubu ile çalışılmış ve belli senaryolar için hem Test Suite Designer (TSD) aracı ile hem de OSÇ-AÖD ile OSÇ’ler oluşturulmuştur. Odak grubuna uygulanan anket yoluyla elde edilen karşılaştırma sonuçları, OSÇ-AÖD yaklaşımının TSD yaklaşımına göre kolay kullanım ve tekrar kullanılabilirlik gibi bazı iyileştirmeler içerdiğini göstermektedir
Araştırmacılarımız Soruyor, Biz Cevaplıyoruz: Açık Erişim ile İlgili Doğru Bilinen Yanlışlar
No full textİzmir Yüksek Teknoloji Enstitüsü Daire Başkanı Gültekin Gürdal moderatörlüğünde 24 Ekim 2024 tarihinde Açık Erişim Haftası kapsamında Doç. Dr. Ahu Arslan Yıldız ve Dr. Öğretim Üyesi Atakan Ekiz ile birlikte gerçekleştirilen "Araştırmacılarımız Soruyor, Biz Cevaplıyoruz: Açık Erişim İle İlgili Doğru Bilinen Yanlışlar" başlıklı canlı yayının kaydıdır
Estimation of Heat Production Rate Using Thermal Data During Exercise in Indoor Environments: a Study of Heat Storage Rate in Male Athletes
No full textThe increasing preference for indoor exercise spaces highlights the relationship between indoor thermal environments and physiological responses, particularly concerning thermal comfort during physical activity. Determining the metabolic heat production rate during exercise is essential for optimizing the thermal comfort, well-being, and performance of individuals engaged in physical activities. This value can be determined during the activity using several methods, including direct calorimetry measurement, indirect calorimetry that uses analysis of respiratory gases, or approximations using collected data such as speed, body mass, and heart rate. The study aimed to calculate the metabolic heat production rate by infrared thermal evaluation (ITE) based on the body's thermal balance approach and compare it with the values determined by indirect calorimetry (IC). Fourteen participants volunteered for the study, using a cycling ergometer in a controlled climatic chamber. After the familiarization sessions, maximal O2 intake levels (VO2max) were determined through maximal graded exercise tests. Subsequently, constant work rate exercise tests were performed at 60% of VO2max for 20 min. The metabolic heat production rates were calculated by IC and ITE for each athlete individually. Respiratory gases were used to determine IC, while body skin and core temperatures, along with physical environmental data, were applied to calculate ITE using the human body thermal balance approximation of ASHRAE. According to the results, heat storage rates were misleading among the body's heat transfer modes, particularly during the first 8 min of the exercise. ITE showed a moderate level of correlation with IC (r: 0.03-0.86) with a higher level of dispersion relative to the mean (CV%: 12-84%). Therefore, a new equation (ITEnew) for the heat storage rates was proposed using the experimental data from this study. The results showed that ITEnew provided more precise estimations for the entire exercise period (p > 0.05). Correlations between ITEnew and IC values were consistently strong throughout the exercise period (r: 0.62-0.85). It can be suggested that ITEnew values can predict IC during the constant work rate steady-state exercise
Water Dams: From Ancient To Present Times and Into the Future
No full textSince ancient times, dams have been built to store water, control rivers, and irrigate agricultural land to meet human needs. By the end of the 19th century, hydroelectric power stations arose and extended the purposes of dams. Today, dams can be seen as part of the renewable energy supply infrastructure. The word dam comes from French and is defined in dictionaries using words like strange, dike, and obstacle. In other words, a dam is a structure that stores water and directs it to the desired location, with a dam being built in front of river valleys. Dams built on rivers serve various purposes such as the supply of drinking water, agricultural irrigation, flood control, the supply of industrial water, power generation, recreation, the movement control of solids, and fisheries. Dams can also be built in a catchment area to capture and store the rainwater in arid and semi-arid areas. Dams can be built from concrete or natural materials such as earth and rock. There are various types of dams: embankment dams (earth-fill dams, rock-fill dams, and rock-fill dams with concrete faces) and rigid dams (gravity dams, rolled compacted concrete dams, arch dams, and buttress dams). A gravity dam is a straight wall of stone masonry or earthen material that can withstand the full force of the water pressure. In other words, the pressure of the water transfers the vertical compressive forces and horizontal shear forces to the foundations beneath the dam. The strength of a gravity dam ultimately depends on its weight and the strength of its foundations. Most dams built in ancient times were constructed as gravity dams. An arch dam, on the other hand, has a convex curved surface that faces the water. The forces generated by the water pressure are transferred to the sides of the structure by horizontal lines. The horizontal, normal, and shear forces resist the weight at the edges. When viewed in a horizontal section, an arch dam has a curved shape. This type of dam can also resist water pressure due to its particular shape that allows the transfer of the forces generated by the stored water to the rock foundations. This article takes a detailed look at hydraulic engineering in dams over the millennia. Lessons should be learned from the successful and unsuccessful applications and operations of dams. Water resource managers, policymakers, and stakeholders can use these lessons to achieve sustainable development goals in times of climate change and water crisis
Methylene Blue (mb) Loaded Zif-8 Synthesis, Characterization and Investigation of Photodynamic Therapy Activity on Breast Cancer
No full textGünümüzde meme kanserinin teşhis ve tedavisinde çeşitli yöntemler kullanılmasına rağmen, geleneksel yöntemlerin ilaç direnci, ilaç sitotoksisitesi, metastaz ve nüks gibi dezavantajları vardır. Bu nedenle, hastalığın erken teşhisi ve tedavi sürecinin iyileştirilmesi için yeni yöntemler geliştirilmesi gerekmektedir. Fotodinamik tanı ve tedavi, son yıllarda bu bağlamda önem kazanan bir yaklaşımdır. Bu çalışmanın temel amacı, metal-organik iskeleleri ilk kez fotodinamik tedavi ile birlikte metilen mavisinin meme kanseri tedavi sürecine dahil etmek için kullanmaktır. Metilen mavisi kullanılan nano-taşıma sistemi, meme kanseri hücre hatları MDA-MB231 ve MCF-7 üzerindeki sitotoksik etkisi açısından incelenmiştir. ZIF-8'in bozunarak hücrelere çinko sağlaması nedeniyle, bu malzemenin fotodinamik tedaviye ek olarak terapötik bir özellik göstermesi beklenmiştir. Ayrıca, tek bir nanopartikül içerisinde birden fazla sitotoksik bileşenin birleştirilmesi ve bunların kombine etkileri değerlendirilmiştir. Yeni nesil nano taşıyıcılar, metilen mavisini düşük pH'a sahip kanser hücrelerinde spesifik olarak salmak üzere tasarlanmış olup, sağlıklı dokulara zarar vermekten kaçınılarak tedavi sürecinin kalitesinin artırılması hedeflenmiştirAlthough various methods are used today in the diagnosis and treatment of breast cancer, traditional approaches have disadvantages such as drug resistance, drug cytotoxicity, metastasis, and relapse. Therefore, new methods need to be developed for early diagnosis of the disease and improvement of the treatment process. Photodynamic diagnosis and therapy have gained importance in this context in recent years. The primary purpose of this study was to use metal-organic frameworks for the first time to include methylene blue in the breast cancer treatment process with photodynamic therapy. The nano-delivery system using methylene blue was examined for its cytotoxic effect on breast cancer cell lines MDA-MB-231 and MCF-7. Since ZIF8 degrades and provides zinc to cells, this material was expected to have an additional therapeutic property alongside photodynamic therapy. In addition, the combination of multiple cytotoxic components in a single nanoparticle and their combined effects was evaluated. The new generation nanocarriers were designed to release methylene blue specifically in cancer cells with low pH, avoiding damage to healthy tissues and enhancing the quality of the treatment process
Beyond Lux: Methods for Species and Photoreceptor-Specific Quantification of Ambient Light for Mammals
No full textBackgroundLight is a key environmental regulator of physiology and behaviour. Mistimed or insufficient light disrupts circadian rhythms and is associated with impaired health and well-being across mammals. Appropriate lighting is therefore crucial for indoor housed mammals. Light is commonly measured in lux. However, this employs a spectral weighting function for human luminance and is not suitable for 'non-visual' effects of light or use across species. In humans, a photoreceptor-specific (alpha-opic) metrology system has been proposed as a more appropriate way of measuring light.ResultsHere we establish technology to allow this alpha-opic measurement approach to be readily extended across mammalian species, accounting for differences in photoreceptor types, photopigment spectral sensitivities, and eye anatomy. We develop a high-throughput method to derive spectral sensitivities for recombinantly expressed mammalian opsins and use it to establish the spectral sensitivity of melanopsin from 13 non-human mammals. We further address the need for simple measurement strategies for species-specific alpha-opic measures by developing an accessible online toolbox for calculating these units and validating an open hardware multichannel light sensor for 'point and click' measurement. We finally demonstrate that species-specific alpha-opic measurements are superior to photopic lux as predictors of physiological responses to light in mice and allow ecologically relevant comparisons of photosensitivity between species.ConclusionsOur study presents methods for measuring light in species-specific alpha-opic units that are superior to the existing unit of photopic lux and holds the promise of improvements to the health and welfare of animals, scientific research reproducibility, agricultural productivity, and energy usage
Anomalous Crustal Structure Beneath the Örenli-Eğiller Depression Zone, Inferred From Magnetotelluric Studies, Western Anatolia, Türkiye
No full textIn Türkiye, the prevalence of high radiogenic granites makes them ideal locations for initiating enhanced geothermal system (EGS) projects. One such occurrence of these granites is observed in the Kozak area of the Bergama region. To assess the energy potential of this site, a magnetotelluric (MT) survey was conducted, focusing on determining the depth distribution of the intrusive granite. The survey employed dimensionality analysis, utilizing Bahr skew and phase tensor analyses that denote a 2D subsurface nature up to 100 s and beyond that a 3D nature. In the present study, we interpreted MT data up to 100 s. The data collected, including rotated impedance tensors and tippers, were inverted using a nonlinear conjugate gradient algorithm integrated into the MT interpretation software of the WinG Link 2D inversion data modeling package. Multiple homogeneous half-space initial models were tested during the 2D inversion process. The findings indicate the existence of a midcrustal conductor associated with graphites and iron sulfides in the source region. This conductivity may be attributed to processes such as exsolution of metamorphic fluids, influx of mantle sources, or the entry of magmatic fluids through transcrustal fault zones. The findings indicate that the intrusive granite was emplaced along a NE–SW major fault, penetrating shallow crustal levels. The depth of this granite intrusion is determined to be 15 km, covering an outcrop area of 60 km². This detailed geological information allows a comprehensive assessment of the power-generating capacity of the intrusive granite. The results of this investigation contribute valuable insights for the development and optimization of Enhanced Geothermal System (EGS) projects in the region. © 2024, TUBITAK. All rights reserved
The Statistical Assessment of Variables Affecting Conservation Condition for Historic Houses
No full textConservation condition is the structural state of a historic building at a particular time. This study aims to determine the variables affecting conservation condition of heritage buildings in historic urban sites. The methodology includes selection of the case study, site survey and listing of historic house characteristics with conventional tools of architectural conservation, and determination of variables affecting their conservation condition with statistical tools. The houses in a portion of Kuyulu neighborhood, and in a portion of Kurtuluş Street, presenting variety in terms of built heritage characteristics in Antakya historic urban site, which experienced a destroying earthquake sequence in 2023, were focused on. The dataset prepared in 2019 site survey is examined by T-tests, ANOVA, regression, and exploratory spatial data analysis statistical tools. As a result, construction technique, land use, and number of storeys were determined as significant variables affecting conservation condition. While addressing abandonment issues and considering both commercial and residential functions for adaptive reuse can positively affect conservation conditions, it is crucial to recognize buildings with combined construction systems show a negative effect on conservation condition which should not be preferred in future constructions and need priority for consolidation interventions. Meanwhile, the construction period and alterations are revealed as insignificant variables on conservation condition. The study concludes that systematic planning, guided by statistical insights, can prioritize interventions and enhance positive variables corresponding to the heritage qualities that have positive impact on conservation condition while mitigating negative ones, thus ensuring the preservation of historic urban sites. © 2024, Avestia Publishing. All rights reserved
