Yazarlar
- Gul, Muhammet(16)
- Kahraman, Gökhan(13)
- Onat, Onur(13)
- Yucesan, Melih(12)
- Etli, Serkan(11)
- Mete, Suleyman(11)
- Akkurt, Nevzat(10)
- Karataş, Mehmet(10)
- Utku, Anıl(10)
- Yön, Burak(10)
- Akmaz, Düzgün(8)
- Cemalgil, Selim(8)
- Demir, Yakup(8)
- Ergen, Burhan(8)
- Çil, Zeynel Abidin(8)
- Akgül, Melek(7)
- Doğan, Gürkan(7)
- Gülmez, Nihan(7)
- Xu, Qian(7)
- Yildirim, Ozal(7)
- Yilmaz, Mehmet(7)
- Özceylan, Eren(7)
- Celik, Erkan(6)
- Göçmen, Elifcan(6)
- Orhan, Ahmet(6)
- Ertarğın, Merve(5)
- Serin, Faruk(5)
- Yilmazer, Merve(5)
- Zheng, Qiang(5)
- Akpolat, Mustafa(4)
- Atangana, A(4)
- Baskonus, HM(4)
- Bulut, H(4)
- Ding, Yulong(4)
- Dogan, Akar(4)
- Eristi, Huseyin(4)
- Hammouch, Z(4)
- Işık, Erdem(4)
- Karakose, Mehmet(4)
- Kaya, Sema Kayapinar(4)
Yayınlar
- MakaleYalnız künye2021Temiz enerji sektörü, teknoloji sektörü ve ham petrol arasındaki yayılım ilişkisi
Ekinci, Ramazan; Gençyürek, Ahmet Galip
Küresel ısınmanın sonucu olarak ortaya çıkan iklim değişikliği yenilenebilir enerjiye diğer bir ifadeyle temiz enerjiye olan ilgiyi artırmıştır. Gelişen teknolojiyle birlikte verimliliğin artması ve maliyetlerin azalması sonucunda da yenilenebilir enerji tüketimi hızlanmıştır. Petrol piyasasının yenilenebilir enerjinin ikamesi olması, teknolojinin de yenilenebilir enerjinin önemli bir girdisi olması nedeniyle teoride yenilenebilir enerjinin her iki değişkenden etkilendiği düşünülmektedir. Yapılan çalışma ile teoride ileri sürülen bu görüş hem ortalamada hem de varyansta nedensellik ilişkisinin tespitine olanak sağlayan Hong (2001) yöntemiyle incelenmek istenmektedir. Temiz enerji sektörü, teknoloji sektörü ve petrol piyasası sırasıyla Willderhill Endeksi (ECO), ArcaTech Endeksi ve WTI tarafından temsil edilmektedir. 2004-2019 döneminin analiz edildiği çalışma sonucunda ortalamada temiz enerji sektöründen petrol piyasasına doğru, varyansta ise; petrol piyasasından temiz enerji sektörüne doğru Granger nedenselliğin olduğu tespit edilmiştir. Kappa-1 yöntemiyle belirlenen varyans kırılma tarihlerinin dikkate alınması sonrasında nedensellik ilişkilerinin varlığında herhangi bir değişim gözlemlenmemiştir. Elde edilen sonuçların araştırmacılara, politika yapıcılara ve yatırımcılara önemli bilgiler sunacağı düşünülmektedir.
AtıfOpenAlex2TR Dizin3
İncele - MakaleAçık Erişim2021The Effect of Carbon Black on Moisture Performance of Asphalt Pavements
Geçkil, Tacettin; İnce, Ceren Beyza; Aksağan, Zülfükar
In this study, the effects of carbon black (CB) additive obtained from waste tires on the moisture performance of hot mix asphalt pavements were investigated. For this purpose, modified asphalts were prepared by adding 5%, 10%, 15% and 20% CB by weight to pure asphalt with penetration class B 160/220. Physical properties of pure and modified asphalts were determined by penetration, softening point and ductility tests, and workability properties were determined by rotational viscometer (RV) test. Then, the optimum asphalt content of the mixture was determined according to Marshall design method by using aggregate and pure asphalt for mixture design. Based on this determined ratio, pure and modified asphalts and hot mix samples were prepared. Pure and CB added modified mixture samples were subjected to Marshall stability, retained Marshall stability (RMS) and indirect tensile strength (ITS) tests. According to the physical test results, it was observed that the hardness and workability temperatures of the modified binders increased with the CB additive. According to the test results of the mixture, it was observed that CB additive had an improving effect on the moisture performance of road pavements due to the significant increases in Marshall stability, RMS and indirect tensile strength ratio (ITSR) values, especially at the rate of 10% CB.
AtıfOpenAlex5İncele - MakaleAçık Erişim2021Application Of The Passive House Certification System In Existing Buildings: EnerPHit Certification System
Erdem, Necla Seval; Asikoglu, Ahunur; Altun, Müjde
In order to improve today's conditions and to ensure a healthy life for future generations, different solutions have been sought in different areas around the world and important steps have been taken in this direction. As the building sector is one of the leading sectors in terms of energy consumption, steps towards creating living conditions in comfortable and healthy spaces made by various regulations, directives, etc. started to be taken with studies, while reducing the energy use in buildings. According to the Energy Performance in Buildings Directive-recast published by the European Union in 2010, member states were asked to set and implement their own NZEB (nearly zero energy building) targets. During this period, there has been an increase in the use of existing certification systems whose criteria meet the country's NZEB objectives. In recent years, countries in different climatic zones have started to construct buildings that comply with the Passive House certification system and the EnerPHit certification system, the version used in existing buildings. In the study, specifications have been analyzed in detail and the results achieved over values through 34 different EnerPhit certified buildings in the world, including one in Turkey. With this study, it is aimed to contribute to the literature with the examination the analysis of EnerPHit certification system criteria, the application techniques, potential for Turkey. Reducing the dependence on foreign energy in Turkey with energy efficient improvement of the existing building stock in country, creation of healthy and comfortable and energy consumption costs will be provided.
AtıfOpenAlex2TR Dizin2İncele - MakaleAçık Erişim2021Comparative Performance Analysis of Sinusoidal Pulse Width and Space Vector Pulse Width Modulations for Off-Grid Inverters
Zengin, Bilgin; Arslanoğlu, İbrahim
Since alternating current is widely used in many systems, it is desired to convert the direct current input voltage to a symmetrical alternating current output voltage with the desired amplitude and frequency. For this purpose, first of all, information about inverters and multilevel inverters is given in the study. Then, pulse width modulation techniques are explained and the working logic of Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM) techniques are examined in detail among these modulation techniques. Finally, the simulations of the inverters on R (Resistive) and R-L (Resistive-Inductive) loads are modeled using the grid-independent two-level SPWM and three-level SVPWM control method in MATLAB/Simulink environment. These measurements made in the Simulink environment were compared with the theoretical calculations and it was tried to determine which of the models showed the best performance in terms of power quality.
- MakaleAçık Erişim2021PLC ve SCADA Kullanılarak Bir Orcik Üretim Sisteminin Otomasyonu
Gencer, Cetin; Üstündag, Aybıke
Orcik, Elazığ yöresinde üzümden ya da duttan elde edilen şıranın un ve özel bir toprakla bulamaç haline getirilipceviz dizili ipin bu bulamaca istenilen kalınlığa göre bir veya daha fazla kez batırılıp güneşte kurutulmasıyla elde edilenyöresel bir üründür. Bu çalışmada, Türkiye'de tüketiminin yanısıra Avrupa ülkelerine de ihraç edilen orciğin fabrikaotomasyon sistemi ile üretimine yönelik bir benzetimi yapılmıştır. Doğal klasik yöntemlerle üretilen orciğin her birüretim aşaması ele alınarak Programlanabilir Mantıksal Denetleyici (PLC) otomasyon sistemi ile tasarımı yapılmış veSCADA üzerinde benzetimi gerçekleştirilmiştir. Elektrikli makineler, hızla büyüyen otomasyon hızının bir sonucuolarak sektörün bir parçası haline gelmiştir. Geleneksel endüstriyel işlemler makinelerin manuel çalıştırılmasıyla olur vebu işlemler manuel müdahaleye bağlıdır. Bu süreç zaman alıcı ve pahalıdır. Endüstrilerdeki yönlendirme görevlerininotomatikleştirilmesi verimliliği arttırır. Minimal insan müdahalesiyle PLC gibi otomasyon araçları kullanılaraktekrarlayan sürecin otomasyonu, geliştirilmiş verim, azaltılmış işletme maliyetleri, geliştirilmiş üretim hacimleri, dahaiyi kalite kontrol ve endüstriyel güvenlik sağlanır. Tasarlanan sistemle, orcik üretiminin klasik yöntem yerine PLCtabanlı otomasyon sistemine geçişi amaçlanmıştır.
- MakaleAçık Erişim2021Reuse of Industrial Metal Wastes as Partial Replacement of Aggregates in Mortar Production
Gülmez, Nihan
Sustainable waste management is becoming more and more important in the construction industry due to increasing waste costs as well as environmental effects. As a result of increasing level of wastes and environmental damage, the use of these wastes has become the focus for beneficial construction activities and sustainable industrial applications. This study presents experimental results on the effect of industrial wastes on the performance of cementitious mixtures. The scope of this study, therefore, was to assess the effect of waste aluminium on physical and mechanical properties of cement based mixtures prepared in different compositions. Consistency, bulk density, porosity, absorption, flexural and compressive strength tests were carried out on mixtures produced by using waste aluminium aggregates in different percentages instead of fine aggregate. Results showed that mixtures prepared with 4% aluminium aggregates had the highest water absorption and porosity. With the addition of %1 lathe waste, it was observed that the flexural behavior of mortar was maximum and the optimum percentage for flexural strength was noted. In addition, when mixtures produced with the same percentage of aluminium were compared, the amount of binder played a significant role on both compressive and flexural strength. Results have shown that to incorporate aluminium into mixtures can be a suitable solution for recycling in industrial applications.
AtıfOpenAlex5İncele - MakaleAçık Erişim2021Türkiye’de Endüstri 4.0 Döneminde Reklamcılığın Yol Haritasına Yönelik Bir Çalışma
Coskun, Engin; Şener, Betül Çepni
Sanayileşme süreçleri teknolojinin gelişimi ile birlikte belirli periyotlar halinde gelişim ve değişim göstermektedir. Günümüzde yapay zekaya sahip makinelerin var olduğu, ileri seviyelerde bağlantısallığın sağlandığı, yapay zeka, büyük veri, nesnelerin interneti, ileri teknoloji video teknolojilerinin kullanılmakta olduğu bir dönem olan Sanayi 4.0 kavramından söz edilmektedir. Bu teknolojilerin gelişim göstermesi ile insanoğlu daha önceki sanayi dönemlerinde olduğu gibi üretim sektöründen hizmet sektörüne teknoloji transferi sağlamaktadır. Bu dönemde endüstride geliştirilen teknolojiler reklamcılık alanında da uygulanmaya başlanmıştır. Reklamcılık alanına yeni teknolojilerin girmesiyle birlikte reklam teknolojilerinde, reklam türlerinde, reklam medyasında, reklam yöntemlerinde ve reklamın uygulama alanlarında inovatif değişiklikler beklenmektedir. Bu araştırmada da endüstri 4.0 ile birlikte anılan teknolojilerin reklamcılık endüstrisini nasıl değiştireceğini ve geliştireceğini öngörerek, geleceğe yönelik bir yol haritası oluşturulması hedeflenmektedir. Bu kapsamda, yol haritasının oluşturulabilmesi amacıyla reklam uzmanlarından üç aşamadan oluşan Delphi anketi yöntemi kullanılarak veri toplanmıştır. Çalışma kapsamında elde edilen veriler ile reklamcılık alanında endüstri 4.0 ile yaşanan gelişmelerin yansımalarına değinilmiş ve reklamcılığın gelecek yol haritası oluşturulmuştur. Bu doğrultuda yaşanacak değişimlerin reklam endüstrisinde teknolojik altyapıya uyum ve tüketicilerin değişen ihtiyaç ve beklentilerine yanıt verme konuları olduğu sonucuna varılmıştır. Çalışma çıktılarının reklam profesyonelleri ve uygulayıcılarının gelecekteki değişikliklere hazırlanmasına yol gösterici olması ve geleceğin reklam araştırmalarına ışık tutması beklenmektedir.
AtıfOpenAlex1TR Dizin2İncele - MakaleAçık Erişim2021Dynamic Connectedness between Sector Indices: Evidence from Borsa Istanbul
Ekinci, Ramazan; Gençyürek, Ahmet Galip
The aim of the study is to analyze the shock and volatility spillover between BIST Finance, Industry, Technology, Tourism, Transportation, Food, and Retail-Trade sectors. In this direction, daily data obtained between January 5, 2010, and December 4, 2020, were analyzed using a new method named TVP-VAR Diebold Yilmaz Spillover Index developed by Antonakakis et al. (2019). Our results indicate that the industrial and financial sectors are in the leading position in terms of the shock and volatility spillover, while other sectors generally are in the lagging position.
AtıfWoS4OpenAlex6TR Dizin3
İncele - MakaleYalnız künye2021Scopus SJRQ1Assessment of Seismic Behavior Factor of Code-Designed Steel–Concrete Composite Buildings
Etli, Serkan; Güneyisi, Esra Mete
In this study, the seismic behavior factor of steel–concrete composite buildings was examined. For this purpose, 5-, 10-, 15- and 20-story composite moment-resisting frame (CMRF) buildings having concrete-filled steel tube columns and composite beams were designed at medium ductility (DCM) and high ductility (DCH) levels as per the regulations of Eurocode 8. Examined DCM structures were designed for a PGA of 0.2 g while DCH structures were designed for a PGA of 0.4 g. SeismoStruct software was utilized in the design and performance assessment of the case study structures. Nonlinear static pushover and incremental dynamic analyses were used. In the pushover analysis, the uniform and triangular load distributions were adopted while 12 earthquake ground motions were employed in the dynamic analysis. The effect of ductility levels and number of stories on the seismic behavior of CMRFs was studied using the results of the nonlinear analysis. To this, the variation in the lateral response, global yielding value, code-based behavior factor and component, and dynamic behavior factor were presented for CMRF structures with DCM and DCH. It was observed that the behavior factor of all CMRFs exhibited well above the design assumptions, especially DCM class CMRFs.
AtıfScopus16WoS11OpenAlex34
İncele - MakaleAçık Erişim2021Scopus SJRQ1Control of switched reluctance generator in wind power system application for variable speeds
Omaç, Zeki; Cevahir, Ceren
Switched reluctance generators (SRGs) come into prominence in other electrical machines with its simple structure, only stator winding, reliability, high fault tolerance and the possibility of working within wide speed range. These generators are used especially in wind power plants due to their ability to operate in variable speed range and applications of aviation and electric cars. In this study, the control of the SRG was performed. A simulation of SRG driver in Matlab/Simulink was performed and the real-time implementation control of SRG is carried out on DS1103 Ace kit digital signal processor to determine the performance of the SRG. The output voltage of the SRG is controlled by the proportional-integral (PI) voltage controller. As a result, the graphs of change in SRG phases currents and SRG output voltage were obtained according to different parameters. Simulation results compared with experimental results. Consequently, they overlap on experimental results.
AtıfScopus25WoS8OpenAlex27İncele - MakaleYalnız künye2021Scopus SJRQ1Performance of marble powder on cementitious composites including waste steel chips as an additive
Gülmez, Nihan
The reuse of industrial waste materials in cement-based composites contributed to preventing increasing environmental problems and reducing production costs. This article examined the effectiveness of using recycled steel chips (Ast) from metal industry waste and waste marble powder (BMP) instead of cement and the possibility of obtaining eco-efficient specimen. While steel chips included in mortars as additives decreased workability, marble powder increased it. An increment in the level of substitution of steel chips resulted in a subsequent increase in water absorption percentages and apparent porosities of mortars. Maximum flexural strength was obtained in 2% steel chips-10% marble powder in waste system.
AtıfScopus16WoS15OpenAlex21İncele - MakaleYalnız künye2021Scopus SJRQ1Crack failure in hydrodynamically lubricated bearings: A case study hydraulic turbine
Taşgın, Yahya; Kahraman, Gökhan
This study investigates the trunnion crack of a 50 MW hydraulic turbine in the generator guide bearing. The crack area has been examined metallographically and the fixing method for the the trunnion crack has been explained. Result of the study shows that the reason for the formation of the bearing trunnion crack can be the thermal stresses that occur during the mounting of the bearing trunnion to the turbine shaft and the material fatigue that occurs during the operation of the hydraulic turbine.
AtıfScopus9WoS7OpenAlex9İncele - MakaleAçık Erişim2021Scopus SJRQ1Thermoset powder coating wastes as filler in LDPE – Characterization of mechanical, thermal and morphological properties
Kismet, Yilmaz; Dogan, Akar; Wagner, Manfred H.
In this study, three different electrostatic powder coating wastes of thermoset structure were used as fillers for low-density polyethylene (LDPE). The mechanical, thermal, and morphological properties of these composites materials are reported. The thermoset powder coating wastes were hydrolyzed using water and alcohol, and then 10%, 20%, and 30% by weight of the deactivated wastes were mixed with LDPE, first in a mechanical dry mixer, and subsequently homogenized by melt compounding in an extruder at about 160 °C. Standard tensile test bars and plate-shaped samples were produced from these homogeneous compounds by injection molding. The effects of adding hydrolyzed powder coating wastes on the properties of LDPE were determined by mechanical, thermal, and morphological tests. Tensile strength and perforation threshold of the sample filled with powder coating wastes decreased to some extent compared to un-filled sample. However, an increase in izod impact and bending strengths has been observed. The results of this investigation demonstrate that powder coating wastes with thermoset structure can be used as fillers in LDPE.
AtıfScopus13WoS15OpenAlex16İncele - MakaleYalnız künye2021Scopus SJRQ1Sustainable supplier evaluation and transportation planning in multi-level supply chain networks using multi-attribute- and multi-objective decision making
Lo, Huai-Wei; Liaw, Ching-Fang; Gul, Muhammet; Lin, Kuan-Yu
Supplier selection and transportation planning are essential tasks in managing supply chain networks (SCNs). The choice of a supplier has a significant influence on the transportation planning of SCNs, as the transportation routes will change. A limited number of studies in the literature have addressed the supplier selection and transportation planning issues simultaneously. This study proposes a two-stage multi-criteria decision-making (MCDM) approach for sustainable supplier evaluation and transportation planning in multi-level SCNs. Initially, a supplier evaluation framework is proposed using the modified indifference threshold-based attribute ratio analysis (ITARA) and the performance calculation technique of the integrated multiple multi-attribute decision-making (PCIM-MADM) to determine the supplier's performance index. Subsequently, a multi-level SCN model is established, and the sustainable supplier selection and transportation planning problem is solved by the fuzzy multi-objective linear programming (FMOLP) method. A set of real-world data provided by a smart audio manufacturing company has been used to demonstrate the proposed approach. Decision-makers understand the importance of criteria through the weights constructed by the modified ITARA. Moreover, the results of the PCIM-MADM can effectively determine the supplier's ranking and provide improving strategies for underperforming suppliers. The augmented max–min technique of the FMOLP can produce a single optimal solution of the transportation allocation. The results show that our approach can effectively evaluate sustainable supplier performance and optimize transportation planning in SCNs.
AtıfScopus67WoS56OpenAlex64İncele - MakaleYalnız künye2021Scopus SJRQ2Smart airport: Evaluation of performance standards and technologies for a smart logistics zone
Göcxmen, Elifcan
Owing to the current context of Industry 4.0, the importance of smart technologies in airport systems have increased substantially. State-of-art applications for transportation planning incorporating baggage services, routing, security, and safety are an evolving domain for both practitioners and researchers dealing with aviation applications. In this context, this paper seeks to answer these questions: Which standards are aimed at a smart airport to make the transportation planning sound? Which propositions are made based on the obtained prioritized standards? This study deals with standards including Environmental Effects, Docking & Navigation, Object Detection & Protection, Communications & Integration, and Terminology using a practical decision support system based on an analytical hierarchy process (AHP) and fuzzy inference system (FIS). Computational results reveal that the Object Detection & Protection standard has an effect on a safe and smart system. To give an overview of this standard for a smart logistics zone (SLZ), an architecture of autonomous robot units and a baggage handling system is proposed in this study. The suggested approach analyzes the obstacle photos obtained by cameras and allows the end-user to control the calculations visually. This research could provide advice to airport planners about smart policies and improving operations.
AtıfScopus25WoS10OpenAlex26İncele - MakaleYalnız künye2021Scopus SJRQ1Bacterial crack healing in metakaolin based geopolymer mortars
Yılmazer Polat, Berivan; Uysal, Mucteba
Geopolymer mortars have emerged as an environmentally friendly binding alternative to conventional cement. However, the gaps in their structure and early cracks reduce their service life. There are various bacterial healing studies in the literature that have been conducted on cemented mortar cracks. Nevertheless, the present study focuses on the healing of metakaolin based geopolymer mortar cracks. For this purpose, mortars with different molarities were prepared with two different endospore forming methods that did not require encapsulation or mixed chemical processes for the bacterial crack repairs on the geopolymer mortars. These mortars were then left in different healing environments with crack damage. The samples were tested using physical, optical and internal structure analyses. As a result, the cracks were improved by reducing the amount of gaps in the samples. The results showed that it is possible to bacterially repair early cracks in new generation ceramic materials with alkali-activated mortars and reduce the amount of gaps.
AtıfScopus41WoS35OpenAlex36İncele - BildiriAçık Erişim2021Designing the Clamp System with the Emergency Braking System in the trains by using PLC and SCADA
Ustundag, Aybike; Gencer, Cetin; Paul, R.
As a result of the developments in rail technologies, the vehicles and equipment used in these systems are also developing rapidly. It is in a rapid technological development in vehicles used in rail systems. The resistance forces affecting the movement of the rail system vehicles try to prevent its movement. In addition, the incident adherence and skidding that occur during the course of the rail system vehicles play an important role in the movements of these vehicles. Calculation of forces affecting the movement of rail system vehicles and designing these vehicles accordingly is also important for the safety of these vehicles. When braking is applied on a train running at a certain speed; It stops for a certain time and distance according to road condition, braking and speed on the train. The distance traveled until braking and stopping is the braking distance. Trains have an emergency braking system, but this system locks the train wheels. In this study along with the Anti-Lock Braking System (ABS), the rail clamping system was designed with PLC and SCADA. By using the ABS used in cars on the locomotive and wagons of the train, it is aimed to lock the wheels when the train brakes and to prevent the train from derailment in case of sudden braking with the rail clamp system.
AtıfScopus7OpenAlex7İncele - MakaleYalnız künye2021Scopus SJRQ2A modified failure modes and effects analysis using interval-valued spherical fuzzy extension of TOPSIS method: case study in a marble manufacturing facility
Gul, Muhammet; Ak, M. Fatih
Failure modes and effects analysis (FMEA) is a commonly used step-by-step approach to assess potential failures existing in a product or process design. In this paper, a modified FMEA model based on an interval-valued spherical fuzzy extension of technique for order preference by similarity to ideal solution (IVSF-TOPSIS) is proposed to cope with drawbacks of the traditional risk priority number (RPN) computation. Spherical fuzzy sets are the integration of Pythagorean fuzzy sets and neutrosophic sets. They provide more freedom to experts in decision making by including the degree of membership, non-membership, and hesitation of fuzzy sets. Therefore, initially, TOPSIS is merged with a special branch of spherical sets “interval-valued spherical fuzzy sets” to determine priorities of emerged failures. As a novelty to traditional RPN of FMEA, three parameters called cost, prevention, and effectiveness in addition to the existed parameters of severity, occurrence and detection are attached to the proposed approach. Weights of these parameters are determined via an interval-valued spherical weighted arithmetic mean operator (IVSWAM). As a demonstration, a case study in a marble manufacturing facility is provided to show the applicability of the novel model. Results show that the most crucial failure modes concern with the maintenance and repairing works of the factory and the lack of technical periodic checks of lifting vehicles regarding “block area: crane” failures. Some comparative and validation studies are also performed to test the solidity of the approach.
AtıfScopus108WoS93OpenAlex103İncele - MakaleYalnız künye2021Scopus SJRQ1Effect of pumice powder and artificial lightweight fine aggregate on self-compacting mortar
Etli, Serkan; Cemalgil, Selim; Onat, Onur
An experimental program was conducted to investigate the fresh properties, mechanical properties and durability characteristics of the self-compacting mortars (SCM) produced with pumice powder and Artificial Lightweight Fine Aggregate (aLWFA). aLWFA was produced by using fly ash. A total of 16 different mixtures were designed with a constant water-binder ratio of 0.37, in which natural sands were partially replaced with aLWFA and pumice powder at different volume fractions of 5%, 10% and 15%. The artificial lightweight aggregates used in this study were manufactured through cold bonding pelletisation of 90% of class-F fly ash and 10% of Portland cement in a tilted pan with an ambient temperature and moisture content. Flowability tests were conducted on the fresh mortar mixtures beforehand, to determine the self-compacting characteristics on the basis of EFNARC. To determine the conformity of the fresh mortar characteristics with the standards, mini-slump and mini-V-funnel tests were carried out. Hardened state tests were conducted after 7, 28 and 56 days to determine the flexural strength and axial compressive strength respectively. Durability, sorptivity, permeability and density tests were conducted at the end of 28 days of curing time. The test results showed that the pumice powder replacement improved both the fresh state and the hardened state characteristics of the mortar and the optimum mixture ratio was determined as 15%, considering other studies in the literature. In the aLWFA mixtures used, the mechanical and durability characteristics of the modified compositions were very close to the control mixture. It is concluded in this study that mixtures with pumice powder replacement eliminated the negative effects of the aLWFA in the mortars and made a positive contribution.
AtıfScopus16WoS15OpenAlex17İncele - MakaleYalnız künye2021Scopus SJRQ1A new type of two-supply, one-return, triple pipe-structured heat loss model based on a low temperature district heating system
Xu, Qian; Wang, Kang; Zou, Zhenwei; Zhong, Liqiong; Akkurt, Nevzat; Feng, Junxiao; Xiong, Yaxuan; Han, Jingxiao; Wang, Jiulong; Du, Yanping
Based on the design concept of a fourth-generation smart pipe network system, this paper innovatively proposes a new TOTS (Two-supply/One-return, triple pipe structure) arrangement method for district heating systems. Moreover, to accurately predict the heat loss due to the pipeline operation of the multi-pipe system, based on the multipole calculation method, a new heat loss theoretical analytical model for the TOTS was created; additionally, a corresponding three-dimensional numerical simulation model was established, which was analyzed and numerically solved. The results showed that in comparison with thermal loss data measured by Danfoss et al., the above analytical and numerical models have a high accuracy, and the deviation is within 2%. Additionally, through calculations, it was found that the distance between the heating pipes is an important factor that affects the total heat loss from the new multi-control heating system and the actual heat exchange between pipes.
AtıfScopus74OpenAlex75İncele
