İnşaat Mühendisliği Bölümü

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A Case Study of Structural Failure of Mounting Systems for Solar Panels from South-Eastern Turkey: An Investigation of Design Parameters under Extreme Weather Events
(2019) Çelik, Gence Genç; Çelik, O.; 101566; İnşaat Mühendisliği
One of the biggest demand of growing population, and cornerstone of the socio-economical growth of Nations, Energy is expected today to be Sustainable, Easy to Reach, Economical, and Continuous. As one of the most common and imperative contributors of this Clean Energy Future, Solar Energy in various forms takes a significant role whole around the World. And It shows a great potential particularly for Turkey which imports the majority of its Energy Resources - including Conventional Ones - from Out Sources, to decrease Energy Dependency on Out-of-country Bases and increase awareness to develop competition in New Technology and Production Fields. Based on a Structural Failure Case of Supporting Frames designed for Solar Photovoltaics (PV) in a Solar Power Plant from Turkey, this paper addresses the significance of Local and Site-Specific Investigation of Climate Data to properly decide on Structural Design Parameters -particularly Loads of Snow and Wind- by staying still comformable with National Codes and Standards.
Citation - WoS: 6
Citation - Scopus: 9
A finite grid solution for circular plates on elastic foundations
(Korean Society of Civil Engineers-ksce, 2015) Karasin, Halim; Gulkan, Polat; Aktas, Gultekin; 5743; İnşaat Mühendisliği
The transmission of vertical or horizontal structural forces to the supporting soil is a challenge to analyze for structures on elastic foundation which represent a complex medium. The two-parameter elastic foundation model that provides a mechanical interaction between the individual spring elements shows a more realistic behavior of the soil reaction than does the single parameter Winkler model. Since the structural behavior of a beam resembles that of a strip in a plate, in this study, the exact stiffness and mass matrices of the beam element on two-parameter elastic foundation is extended to plates. The framework method that replaces a continuous surface by an idealized discrete system can represent a two-dimensional plate. In the light of this situation, circular plates are modeled as an assemblage of individual beam elements interconnected at their neighboring joints in radial and tangential direction. So, a useful tool called finite grid solution as a numerical method developed in this study lead to solve circular plates resting on two parameter elastic foundation problems. Examples for bending of ring, circular and annual plates on elastic foundation are solved to compare with known analytical solutions and other numerical solutions. The comparisons show that the literature and the computed results are compatible.
Citation - WoS: 6
Citation - Scopus: 8
A metaheuristic-guided machine learning approach for concrete strength prediction with high mix design variability using ultrasonic pulse velocity data
(Elsevier, 2023) Selcuk, S.; Tang, P.; İnşaat Mühendisliği
Assessment of concrete strength in existing structures is a common engineering problem. Several attempts in the literature showed the potential of ML methods for predicting concrete strength using concrete properties and NDT values as inputs. However, almost all such ML efforts based on NDT data trained models to predict concrete strength for a specific concrete mix design. We trained a global ML-based model that can predict concrete strength for a wide range of concrete types. This study uses data with high variability for training a metaheuristic-guided ANN model that can cover most concrete mixes used in practice. We put together a dataset that has large variations of mix design components. Training an ANN model using this dataset introduced significant test errors as expected. We optimized hyperparameters, architecture of the ANN model and performed feature selection using genetic algorithm. The proposed model reduces test errors from 9.3 MPa to 4.8 MPa.
Açılı CFRP Ankrajlı Şeritler ile Beton Yüzey Arasındaki Gerilme Deformasyon Davranışı için Yeni Bir Model Önerisi
(2020) Özgür, A. C. Anıl; Ghoroubi, Rahim; Mercimek, Ömer; İnşaat Mühendisliği
Betonarme, çelik veya yığma yapılar birçok farklı nedenden dolayı güçlendirilmeleri veya onarılmaları gerekmektedir. Karbon takviyeli elyaf kumaşlar (CFRP) deprem performansı yetersiz yapıların onarım ve güçlendirme çalışmalarında son 20 yıldır yaygın olarak kullanılmaktadır. CFRP ile geliştirilen onarım ve güçlendirme detaylarında önemli olan tasarım kriterlerinden biri CFRP elemanların yüzeyden soyulmalarını geciktirmektir. Bu amaçla CFRP ile geliştirilen güçlendirme detaylarında ankrajların kullanılması artış göstermiştir. Güçlendirme detaylarında kullanılan fan tipi CFRP ankrajlı CFRP şeritler ile ilgili gerilme-kayma deplasmanı modellerinin ankrajsız CFRP şeritlere göre çok daha sınırlı sayıda olduğu görülmektedir. Bu konudaki sınırlı sayıdaki çalışmada ankrajlar CFRP şeritlere uygulanan eksenel çekme kuvvetine göre 90o açılı olacak şekilde yerleştirilmiştir. Yapılan literatür taramasında eksenel yüke göre değişik açılarda yerleştirilen ankrajlı CFRP şeritlerin eksenel kuvvet taşıma gücü ve gerilme kayma deplasmanı modelleri ile ilgili bir çalışmaya rastlanmamıştır. Bu nedenle deneysel bir çalışma düzenlenmiş ve 28 adet beton yüzeyine yapıştırılan açılı ankrajlı CFRP şerit deney elemanı eksenel çekme kuvveti etkisinde yazarlar tarafından tasarlanan bir deney düzeneği kullanılarak test edilmiştir. Deneysel çalışmada incelenen değişkenler CFRP şerit genişliği ve CFRP şeritler üzerindeki CFRP fan tipi ankrajların açılarıdır. Deneysel çalışma sonucunda açılı ankrajlı CFRP şeritlerin maksimum taşıma gücü değerlerinin hesaplanması için bir denklem ve yeni bir gerilme kayma deplasmanı modeli önerilmiştir.
Ahşap Bağlantı Noktalarında Mekanik Ankraj Sayısı ve Yerleşim Şeklinin Kayma Gerilmesi-Kayma Deplasmanı Davranışı Üzerindeki Etkilerinin Deneysel Olarak İncelenmesi
(2021) Acehan, Ayşegül Özden; Mercimek, Ömer; Ghoroubi, Rahim; Anıl, Özgür; İnşaat Mühendisliği
Ahşap yapılar ve yapı elemanlarında yapıştırıcı ve mekanik bağlantı elemanları ile bir araya getirilmiş birleşim bölgerinin genel yük-deplasman davranışı, kayma gerilmesi- kayma deplasmanı davranışları, yapısal sistemin kapasitesi ve göçme mekanizmaları üzerinde son derece etkilidir. Ahşap-ahşap bağlantı bölgelerinin davranışları, malzemenin mekanik özelliklerine, yapısına ve türüne göre çok büyük oranda değişim gösteren farklı kayma gerilmesi-kayma deplasmanı davranışları sergileyen, incelenmesi gerekli olan önemli bir konudur. Ahşap yapı elemanlarının yapıştırıcı ve yapıştırıcı ile birlikte mekanik ankrajlar ile birleştirilmesi durumunda genel yük-deplasman davranışlarının, bağlantı bölgesindeki gerilme dağılımları ile kayma gerilmesi - kayma deplasmanı davranışlarının incelendiği kapsamlı bir deneysel çalışmaya literatürde rastlanmamıştır. Bu nedenle deneysel bir çalışma planlanmıştır. Bu çalışma kapsamında birbirlerine yapıştırıcı ve yapıştırıcı ile birlikte mekanik ankrajlar ile bağlanmış olan, kenetlenme uzunlukları 180, 240 ve 350 mm olarak değişim gösteren ahşap bağlantı bölgelerinin, eksenel çekme yükü etkisi altındaki genel yük deplasman davranışları deneysel olarak incelenmiştir. Ayrıca çalışma kapsamında birleşim bölgesinde kullanılan mekanik ankraj sayısı ve yerleşiminin değişim göstermesinin, genel yük-deplasman davranışı ve kayma gerilmesi-kayma deplasmanı davranışları üzerindeki etkileri de araştırılmıştır.
Citation - WoS: 8
Citation - Scopus: 16
An analysis on the relationship between safety awareness and safety behaviors of healthcare professionals, Ankara/Turkey
(Oxford Univ Press, 2020) Uzuntarla, Fatma; Kucukali, Serhat; Uzuntarla, Yasin; 20413; İnşaat Mühendisliği
Objectives: This descriptive study aims to examine the relationship between the safety awareness of healthcare professional and their safety behaviors. Methods: The study was carried out on 418 healthcare professionals working in a training and research hospital in Ankara/Turkey. The survey method was used as data collection tool. The questionnaire consisted of 3 sections and 18 questions. First section consisted of questions on sociodemographic characteristics and, second section consisted of the awareness scale and third section consisted of safety behaviors scale. Results: The safety awareness and safety behaviors are scored on a scale from 1 (completely disagree) to 5 (completely agree). The safety awareness and safety behaviors has an average score of 3.85 +/- 0.81 and 3.56 +/- 0.82, respectively. The safety awareness and safety behavior levels of healthcare professionals were found to be high. Conclusion: A significant positive correlation was found between safety awareness and safety behaviors and it was concluded that the increase in safety awareness led to an increase in safety behavior.
Citation - WoS: 9
Citation - Scopus: 12
Assessment of the effectiveness and the initial cost efficiency of hot recycled asphalt using polymer modified bitumen
(Elsevier, 2023) Almusawi, Ali; Shoman, Sarmad; Lupanov, Andrei P.
The drastic increase in environmental concerns and increasing costs of road construction materials necessitate evaluating some alternative solutions. One of the most suitable alternatives is recycling old asphalt pavement to produce reclaimed asphalt pavement (RAP). The RAP materials have been commonly combined with asphalt mixtures during pavement construction. Incorporating RAP material should demonstrate an equivalent or better performance than conventional asphalt mixtures. Conversely, the inclusion of RAP mainly needs to improve performance compared to conventional asphalt mixtures. The key issue of using RAP is to restore the loss properties of aged materials and normally asphalt Agent Rejuvenator (ARA) was used. Also, adding polymers with RAP into the asphalt mixture becomes necessary to obtain the required performance. This study investigated the RAP effects of elastomeric polymer on the performance of the asphalt mixture following Russian standards (GOST). The impact of using PMB with RAP material on the asphalt mixture's performance was primarily considered by employing tests that can reveal the adhesion property. Additionally, the performance of the pavement was evaluated in terms of strength and low-temperature cracking. For this purpose, numerous test methods were implemented to appraise the asphalt performance, such as compressive strength, moisture susceptibility, shear resistance, tensile strength, porosity of the mineral particles, and residual porosity. The results indicated that the overall performance of the asphalt mixtures prepared with RAP and combined with polymer depicted a better performance. Moreover, the initial construction cost for each asphalt composition was estimated and compared. The utilization of PMB increased the cost of the asphalt mixture. However, such an increase in the cost would lead to an increase in the overall performance, especially for RAP mixtures.
Birden Fazla Boşluklu Çift Doğrultulu Betonarme Döşemelerin Zımbalama Performansının İyileştirilmesi için Tekstil ile Güçlendirilmiş Sıva Şeritler ile Güçlendirilmesi
(2021) Mercimek, Ömer; Ghoroubi, Rahim; Anıl, Özgür; Baran, Mehmet; İnşaat Mühendisliği
Betonarme kirişsiz döşemelerde meydana gelebilecek olan ani ve gevrek bir şekilde, hiçbir deformasyon belirtisi göstermeden oluşan zımbalama göçme mekanizması yapı içerisinde yaşayanlara zarar verebilecek son derece tehlikeli bir göçme şeklidir. Bu nedenle tasarım aşamasında kaçınılan göçme mekanizmalarının başında gelmektedir. Betonarme döşemelerde havalandırma, elektrik veya dogalgaz gibi alt yapı sistemlerinin geçirilmesi veya merdiven ya da asansör boşluğu gibi mimari zorunluluklar nedeniyle bırakılan boşlukların, döşemelerin zımbalama dayanımını ve davranışını olumsuz etkilediği bilinmektedir. Ancak birden fazla boşluklu çift doğrultulu betonarme döşemelerin zımbalama yüklemesi etkisi altındaki davranışının incelendiği bir araştırmaya literatürde rastlanmamıştır. Bu nedenle betonarme çift doğrultulu döşemelerde birden fazla boşluğun döşemelerin zımbalama davranışı üzerindeki olumsuz etkilerinin belirlenmesi ve boşlukların meydana getirdiği davranış problemlerinin azaltılabilmesi için tekstil ile takviye edilmiş sıva şeritler ile döşemelerin güçlendirilmesinin incelendiği deneysel bir çalışma planlanmıştır. Bu çalışma kapsamında biri boşluksuz referans elemanı, 4 deney elemanı ise 300x300 mm boyutlarında kare kesitli iki adet boşluklu olacak şekilde toplamda 5 döşeme deney elemanı üretilmiştir. Boşluklu deney elemanlarının ikisi tekstil ile güçlendirilmiş sıva katmanlı (TGSK) şeritler ile güçlendirilerek deney elemanlarının zımbalama davranışı üzerinde boşlukların meydana getirdiği olumsuz etkilerin ne ölçüde iyileştirilebildiği deneysel olarak araştırılmıştır. Çalışma kapsamında TGSK şeritler ile geliştirilen ve uygulanan güçlendirme metodunun döşemelerin zımbalama dayanımını önemli ölçüde artırdığı, boşlukların meydana getirdiği olumsuz etkileri sınırlandırdığı görülmüştür.
Determination of Optimum Bitumen Content in Porous Asphalt Pavement by Different Methods
(2022) İbiş, Ahmet Buğra; Şengöz, Burak; almusawi, Ali; Kaya Özdemir, Derya; Topal, Ali
In recent years, studies on porous asphalt have gained more importance and countries are conducting various studies in order to improve the engineering properties of this type of pavement. As a result of these studies, each country developed its own standard and therefore different optimum bitumen content (OBC) determination methods emerged. This paper investigates the determination of the optimum bitumen content of porous asphalt samples prepared by using different aggregate types and polymers by the methods implemented in Turkey and in other countries. The results have shown that the application of each method yielded different bitumen content.
Citation - WoS: 12
Citation - Scopus: 12
Economic and environmental impacts of utilizing lower production temperatures for different bitumen samples in a batch plant
(Elsevier, 2022) Almusawi, Ali; Sengoz, Burak; Ozdemir, Derya Kaya; Topal, Ali
The utilization of hot mix asphalt (HMA) for road construction necessitates high temperatures during mixing bitumen and aggregate at asphalt plant. The required (mixing) production temperature is calculated by the standard method (ASTM 2493). The application of this method for polymer modified bitumen (PMB) and warm mix asphalt (WMA) have tendency of higher temperatures. Therefore, some alternative methods suggested by literatures for the determination of production temperature for PMB and WMA have been implemented aiming to determine lower temperatures than the standard method (ASTM 2493). Moreover, the economic impacts of the determined production temperatures through different models are evaluated by the estimation of energy consumption in terms of electricity and natural gas costs for the batch type asphalt plants. Besides, the possible environmental effects are calculated by considering the carbon dioxide emissions. The results of this study have shown that the reduction in production temperatures led to a significant decrease in the total construction cost of each type of asphalt and a significant reduction in the estimated carbon dioxide emission. The results of this study can be used as a reference point for the estimation of both economic and environmental impacts of utilizing lower production temperatures for different bitumen samples.
Citation - WoS: 0
Citation - Scopus: 0
Effect of Downstream Expansion of a Long-Throated Flume on Flow Properties
(Gazi Univ, 2021) Hatipoglu, Murat; Gogus, Mustafa; Ucar, Muhammed; 6062
Long throated flumes are widely used flow measurement devices that not requiring site-specific level to flow curves and therefore laboratory experiments. In this study, downstream expansion effect of the long throated flumes with rectangular cross section were analysed for the dimensionless parameters derived from Buckingham's pi theorem and some other known hydraulic quantities such as discharge coefficient, approach velocity coefficient, submergence ratio of the flow etc. Therefore, five downstream transitions with different expansion angles were tested. In each test, the critical depth y(c), the flow head at the depth measurement section h(1), minimum required energy dissipater length L-t and the head after hydraulic jump y(2) were measured for both modular and free flow conditions. The relation of hydraulic quantities of calculated dimensionless parameters with relevant parameters; modular limits, approach velocity coefficients and discharge coefficients etc. were graphed to represent the design relationships for long throated flumes.
Citation - WoS: 6
Citation - Scopus: 10
Environmental impact assessment of coal power plants in operation
(E D P Sciences, 2017) Bartan, Ayfer; Kucukali, Serhat; Ar, Irfan; 20413; İnşaat Mühendisliği
Coal power plants constitute an important component of the energy mix in many countries. However, coal power plants can cause several environmental risks such as: climate change and biodiversity loss. In this study, a tool has been proposed to calculate the environmental impact of a coal-fired thermal power plant in operation by using multicriteria scoring and fuzzy logic method. We take into account the following environmental parameters in our tool: CO, SO2, NOx, particulate matter, fly ash, bottom ash, the cooling water intake impact on aquatic biota, and the thermal pollution. In the proposed tool, the boundaries of the fuzzy logic membership functions were established taking into account the threshold values of the environmental parameters which were defined in the environmental legislation. Scoring of these environmental parameters were done with the statistical analysis of the environmental monitoring data of the power plant and by using the documented evidences that were obtained during the site visits. The proposed method estimates each environmental impact factor level separately and then aggregates them by calculating the Environmental Impact Score (EIS). The proposed method uses environmental monitoring data and documented evidence instead of using simulation models. The proposed method has been applied to the 4 coal-fired power plants that have been operation in Turkey. The Environmental Impact Score was obtained for each power plant and their environmental performances were compared. It is expected that those environmental impact assessments will contribute to the decision-making process for environmental investments to those plants. The main advantage of the proposed method is its flexibility and ease of use.
Citation - WoS: 22
Citation - Scopus: 25
Evaluation of soil-structure interaction effects from system identification of structures subject to forced vibration tests
(Elsevier Sci Ltd, 2019) Star, Lisa M.; Tileylioglu, Salih; Givens, Michael J.; Mylonakis, George; Stewart, Jonathan P.; 42369; İnşaat Mühendisliği
We describe procedures to evaluate the dynamic properties of test structures subject to forced vibration testing. We seek modal vibration periods and damping ratios corresponding to the actual flexible-based response of the structure (incorporating the effects of compliance in the soil medium supporting the foundation) and similar attributes for a fixed-base condition in which only the flexibility of the structure is represented. Our approach consists of using suitable input and output time series with conventional parametric system identification procedures, and as such extends previously developed procedures for use with earthquake recordings. We verify the proposed approach and demonstrate its application using data from two test structures supported on shallow foundations that have been used in forced vibration tests and that have recorded earthquakes. The structures were tested with and without braces to modify their stiffness and were deployed at two sites with different soil conditions. We analyze the results to evaluate experimental period lengthening ratios and foundation damping. The results show (1) strong increases in period lengthening and foundation damping with the wave parameter (dimensionless ratio of structure-to-soil stiffness), (2) compatibility between modal properties from forced vibration testing and earthquake excitation, (3) soil nonlinearity increases period lengthening and modifies foundation damping in a manner that can be reasonably captured in predictive models using equivalent-linear soil properties compatible with a proposed shear strain index.
Citation - Scopus: 0
Farklı savak yüksekliğine ve konfigürasyona sahip dairesel labirent savakların deneysel modellenmesi
(Gumushane University, 2023) Yildiz, A.; Marti, A.İ.; Göğüş, M.; 6062
Due to their zigzag geometry in plain view, labyrinth weirs require less crest length compared to linear weirs in the dam body or in the channels where they are placed. In this study, the effect of the number of cycles (N) and weir heights (P) of the semi-circular labyrinth weirs on the flow efficiency was investigated. Semi-circular labyrinth weirs, unlike triangular and trapezoidal labyrinth weirs, increase the discharge efficiency by making the areas that reduce the flow capacity at the intersection areas more efficient and by allowing the flow to move in a more perpendicular direction to the weir walls. The experiments were carried out on 3 different configurations (N=2, 3 and 4) depending on the number of semi-circles they contain. In all configurations, a total of 3 weir heights (P=0.20, 0.30 m and 0.40 m) were used and 9 test setups were prepared. In addition, to reference the results obtained from circular weirs, experiments were carried out with linear weirs at 3 different weir heights (P=0.20, 0.30 m and 0.40 m), and a total of 12 experiments were carried out. n this study, the effect of the number of cycles (N) and weir heights (P) of the semicircular labyrinth weirs on the discharge efficiency was investigated. The results obtained from the circular labyrinth weir experiments were compared with previous studies and it was seen that the semi-circular labyrinth weirs had higher discharge capacity than the triangular labyrinth weirs. In addition, semi-circular labyrinth weirs provided a longer effective crest length than the triangular form with the same channel width, they provide higher flow rates at the same weir load. © 2023, Gumushane University. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 3
Flow Rate along the Length of the Swirling Vortex Axis at an Intake
(Turkish Chamber Civil Engineers, 2021) Tastan, Kerem; Yildirim, Nevzat; 12654; İnşaat Mühendisliği
In this study, the characteristics of the flow in the region of swirling vortex are examined. The potential flow model based on the summing infinite number of spherical sinks along the vortex core is introduced to predict the flow field and the flow rate along the vortex axis. The flow towards the swirling vortex core has considerable effects on the radial velocity distribution within the ambient fluid flow region near the intake. The agreement between available test data relating to the radial velocity and the method introduced in this study is found to be satisfactory.
Citation - WoS: 0
Citation - Scopus: 0
Frame finite element model for nonlinear and vibration analysis of steel structures with Beam-Column and Column-Base Semi-Rigid Connections
(Gazi Univ, Fac Engineering Architecture, 2022) Ozel, Halil Firat; Saritas, Afsin; 237150; İnşaat Mühendisliği
In this paper, a shear deformable force-based frame finite element with semi-rigid connections is derived for nonlinear analysis of steel structures. Distributed plasticity approach is defined along element length and section depth, and linear or non-linear semi-rigid connection behavior can be specified anywhere along elements without the necessity to define additional nodes and to increase the degrees of freedom of the structural system. To perform vibration analyses with similar accuracy, force-based consistent mass matrix is used considering semi-rigidity in connections and an appropriate shear correction coefficient for I-sections. The element formulation is presented in 2 dimensions to simplify the formulation, and numerical validation and comparison studies are carried out on complex and irregular structures in 2-D and 3-D. In models with semi-rigid connections, the effect of nonlinear behavior on the structural system has been studied in both beam-column and column-bases. In the presented examples, it was possible to push structures higher than the existing displacements, and it was revealed that the nonlinear behavior in the column-base connections could create much more critical results for the structural systems with P-Delta effects. In addition, high-level accuracy results were obtained when performing vibration analyses with the application of force-based consistent mass matrix.
Citation - WoS: 2
Citation - Scopus: 2
Improved Equations for the Profile of a Vertical Air-Core Vortex
(Korean Society of Civil Engineers-ksce, 2023) Tastan, Kerem; Yildirim, Nevzat; 12654; İnşaat Mühendisliği
The available formulas for the profile of a vertical non-air-entraining vortex are not practical because they involve unknown parameters and need measurements of the local viscous-core radii across the height of the air-core vortex. Also, these formulas can not be used for the air-entraining vortices. In the present study, the available formulas involving unknown parameters were further improved. Findings are as follows. 1) the magnitudes of the unknown parameters vary across the height of the profile of the air-core vortex and they are the function of the ratio of the height of the air-core vortex to the submergence of the intake; 2) simple charts and formulas were obtained for the variations of the unknown parameters for the air-core vortices with and without an intake; 3) in lieu of the local viscous-core radius, the radius at the half-depth of the profile of the air-core vortex was used; 4) no laborious work of measurements are needed to determine the local viscous-core radii along the profile of the vortex; and 5) the improved formulas are in good agreement with available test data for the profiles of both the non-air-entraining and the air-entraining vortices with or without a vertically flowing downward intake.
Initial value problems spreadsheet solver using VBA for engineering education
(2018) Dinçkal, Çiğdem; 26773; İnşaat Mühendisliği
Spreadsheet solver using VBA programming has been designed for solving initial value problems (IVPs), analytically and numerically by all Runge-Kutta (RK) methods including also fifth order with calculation of true percent relative error for corresponding RK method. This solver is user-friendly especially for beginner users of Excel and VBA.
Citation - WoS: 18
Citation - Scopus: 23
Measuring fluid flow and heat output in seafloor hydrothermal environments
(Amer Geophysical Union, 2015) Germanovich, Leonid N.; Hurt, Robert S.; Smith, Joshua E.; Genc, Gence; Lowell, Robert P.; İnşaat Mühendisliği
We review techniques for measuring fluid flow and advective heat output from seafloor hydrothermal systems and describe new anemometer and turbine flowmeter devices we have designed, built, calibrated, and tested. These devices allow measuring fluid velocity at high-and low-temperature focused and diffuse discharge sites at oceanic spreading centers. The devices perform at ocean floor depths and black smoker temperatures and can be used to measure flow rates ranging over 2 orders of magnitude. Flow velocity is determined from the rotation rate of the rotor blades or paddle assembly. These devices have an open bearing design that eliminates clogging by particles or chemical precipitates as the fluid passes by the rotors. The devices are compact and lightweight enough for deployment from either an occupied or remotely operated submersible. The measured flow rates can be used in conjunction with vent temperature or geochemical measurements to obtain heat outputs or geochemical fluxes from both vent chimneys and diffuse flow regions. The devices have been tested on 30 Alvin dives on the Juan de Fuca Ridge and 3 Jason dives on the East Pacific Rise (EPR). We measured an anomalously low entrainment coefficient (0.064) and report 104 new measurements over a wide range of discharge temperatures (5 degrees-363 degrees C), velocities (2-199 cm/s), and depths (1517-2511 m). These include the first advective heat output measurements at the High Rise vent field and the first direct fluid flow measurement at Middle Valley. Our data suggest that black smoker heat output at the Main Endeavour vent field may have declined since 1994 and that after the 2005-2006 eruption, the high-temperature advective flow at the EPR 9 degrees 50'N field may have become more channelized, predominately discharging through the Bio 9 structure. We also report 16 measurements on 10 Alvin dives and 2 Jason dives with flow meters that predate devices described in this work and were used in the process of their development. This includes the first advective measurements in the Lau Basin and at the EPR 9 degrees 39.5'N. We discuss potential error sources and how they may affect the accuracy of measurements by our devices and other devices. In particular, we use the turbulent plume theory to evaluate the effect of entrainment of ambient seawater.
Citation - WoS: 3
Citation - Scopus: 4
Mechanical Characteristics of Environmentally Friendly Permeable Pavement: Enhanced Porous Asphalt
(Jordan Univ Science & Technology, 2024) Ibis, Ahmet Bugra; Sengoz, Burak; Almusawi, Ali; Ozdemir, Derya Kaya; Topal, Ali
This study explores the mechanical properties of porous -asphalt pavement, focusing on the influence of various polymers (elastomeric and reactive elastomeric terpolymers) and different aggregate compositions. Two aggregates were utilized: one is exclusively limestone -based and the other is a blend of limestone and basalt aggregates. The research findings unveiled that mixtures containing the conventional bitumen failed to meet the Cantabro loss -test criterion required for porous asphalt, necessitating a maximum threshold of 20%. In contrast, asphalt mixtures modified with polymers exhibited notably superior performance, particularly in terms of permeability, Cantabro loss and the ratio of indirect tensile strength. These results underscore the significant impact of polymer modification on enhancing the crucial mechanical properties of porous asphalt. Therefore, the study suggests the adoption of polymer -modified asphalt as a viable strategy to improve pavement longevity and overall performance, promoting its use for sustainable and durable infrastructure.

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