
Bahadir TunaboyluMarmara University · Department of Metallurgy and Material Engineering
Bahadir Tunaboylu
PhD
About
95
Publications
57,275
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512
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Introduction
Bahadir Tunaboylu currently works at the Department of Met. and Materials Engineering, Marmara University. Bahadir does research in Solid State Physics, Nanoelectronics, Manufacturing, Smart Systems and Energy. He works on electric vehicle technologies, semiconductors, smart sensors and integrated clean energy systems.
Additional affiliations
August 2020 - present
February 2007 - July 2010
December 1997 - February 2007
Education
September 1991 - June 1997
September 1988 - June 1991
September 1984 - June 1988
Middle East Technical University
Field of study
- Metallurgical Engineering
Publications
Publications (95)
Bu makale sürdürülebilirlik, dayanıklılık ve akıllı şehir boyutlarını dikkate alan yeni bir yaşanabilirlik endeksi oluşturmaya odaklanmaktadır. Dirençli Şehir, Sürdürülebilir Şehir ve Akıllı Şehir endeksleri, kentsel yaşamın farklı yönlerini değerlendirmek için bir çerçeve sağlayarak yaşanabilirlik endeksinin oluşturulmasını etkileyebilir. Yeni end...
DMAIC Method for Semiconductor Manufacturing
In the highly competitive semiconductor manufacturing industry, optimizing yield is of utmost importance for improving profitability and maintaining a competitive edge. This case study explores the successful application of the Six Sigma methodology to enhance yield and overall process efficiency within a semiconductor research laboratory in single...
Hekzaborürler arasında lantan hekzaborür (LaB6) 2.4 eV ile 2.9eV arasındaki düşük çalşma fonksiyonu, yüksek erime sıcaklığı, yüksek kimyasal stabilitesi ve düşük buharlaşma sıcaklığı gibi eşsiz özellikleri sayesinde öne çıkmaktadır. Elektron mikroskoplarında elektron kaynağı olarak kullanılan LaB6 katotların magnetron sıçratma (MS) sistemi kullanıl...
Lithium ion battery technology is the most promising energy storage system thanks to many advantages such as high capacity, cycle life, rate performance and modularity. Many transportation applications including marine, aerospace and railway have been utilizing lithium ion batteries. Likewise, there is a dramatic transition from conventional vehicl...
GİRİŞ Günümüz elektron mikroskoplarında en sık kullanılan üç tip filament CeB6, LaB6 ve Tungsten filamentlerdir. Ce ve La elementlerinin 6 bor ile meydana getirdikleri hekzaborür bileşikleri, kristal yapıları sayesinde Tungsten filamente göre daha düşük çalışma fonksiyonu, 10 kat daha yüksek parlaklık, daha düşük buharlaşma değerleri ve 10 kat daha...
The electromobility presents a potential opportunity for nations to develop and produce their domestic cars especially for emerging markets. This paper proposes a new concept, called microfactory, for manufacturing Electric Vehicles (EV). It is a big challenge for newcomers to enter the automotive market as this industry remains heavily under the c...
Membrane systems have become one of the major technologies in water and wastewater treatment processes. In recent decades, membrane processes have made rapid progress owing to their advantageous properties over conventional systems. However, biofouling restricts their widespread application through irreversible deterioration of their structure, per...
The efficient and well-designed warehouses can provide critical advantages for retail stores. They also play a crucial role in the achievement of supply chain management. Nowadays, warehouses have become centers where fast access to the customer is provided apart from the storage and protection of the goods. The objective of this study is to find t...
With the increasing adoption of battery-based energy storage systems, especially in areas such as e-mobility and on- and off-grid energy storage applications, techniques to manage these batteries are being developed to address various application-related challenges. Battery Management Systems (BMS) are used to provide reliable protection for the co...
Blockchain technology offers important opportunities for the supply chain management. This paper aims to overview the employment of blockchain technology in the field of the supply chain. Although the technology has been widely associated with cryptocurrencies, non-financial applications such as supply chain, power, and food industry are also promi...
Increasing electronic appliances in residential buildings have caused researchers to study direct current (DC) powered systems in homes. In this paper, we state a scenario that a home with traditional alternating current (AC) powered appliances are replaced with DC devices. The questions which devices can be replaced, how much savings in terms of e...
One substantial need for human beings is “energy” in daily life. To generate energy especially from fossil fuels are frequently utilized. However; they are about to deplete day by day and this fluctuates fuel prices in addition to their adverse effect on environment. Leading countries are shifting their energy resources from fossil fuels to renewab...
Three different zwitterionic functional trimethoxysilane compounds, 4-(diethyl(3-(trimethoxysilyl)propyl)ammonia)butane-1-sulfonate (EPBS), 4-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)butane-1-sulfonate (MPBS), and 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)propane-1-sulfonate (MPPS), were synthesized and used for the surface modification of c...
Membrane separation has become a prevalent technique in water and wastewater treatment. However, fouling is still the most challenging issue in case of membranes. Fouling causes flux decline, loss in rejection performance, increased energy consumption, etc. Different modification techniques have been applied to mitigate fouling on the membrane surf...
The future of the manufacturing sector is evolving with the Industry 4.0, and its repercussions are felt in the factory, the business, product launch and also impacts customer aspects in the overall cycle. These technological innovations create opportunities for new disruptive entries to the market, for instance in automotive manufacturing. It is w...
The aim of this project is to analyze and reorganize the current processes of the relevant company and to make improvements to increase the efficiency of the processes as a result of the studies and to manage the process flow of the Human Resources Departments in Turkish Technic INC. Current processes are prepared according to five thousand employe...
Thin films of rare-earth hexaborides are promising for wear and corrosion protective, decorative, and thermionic coatings. Among many hexaborides available, due to its unique properties lanthanum hexaboride (LaB6) is used as a bright and long life thermionic electron source mostly in electron microscopes. Unlike single-crystal LaB6 cathodes used to...
Sustainable development and globalization are becoming important subjects for policy makers to formulate the worldwide strategies and rubrics for ensuring simultaneous adoption of its components and monitoring of its consequences. Sustainable Development Goals (SDGs) published by United Nations are the guidelines to incorporate the assurance of sus...
The aim of the project was to increase the success rate of molds due to the measurement mistakes in AKPA Aluminum. Several problems of defects were identified by using 5S and six sigma methods and Pareto analysis, the quality function deployment (QFD ANALYSIS) with the help of Ishikawa Diagram. The project duration included the progress in four qua...
Zwitterionic modification of membrane surfaces is a promising approach to decrease membrane biofouling. In this study, biofouling properties of two commercial polyamide (PA) reverse osmosis (RO) desalination membranes coated with zwitterionic sulfobetaine silane compounds including4-(diethyl(3-(trimethoxysilyl)propyl) ammonia)butane-1-sulfonate (EP...
The bipolar plate is one of the most significant components of a polymer electrolyte membrane (PEM) fuel cell, and contributes substantially to the cost structure and the weight of the stacks. A number of graphite polymer composites with different fabrication techniques have been reported in the literature. Graphite composites show excellent electr...
The eucalyptus and araucaria fibers were used as alternatives to virgin cellulose common in fiber-cement production. Three different types of these virgin-cellulose replacements were utilized as main raw materials while silica sand was the aggregate. Chemical and physical analyses were performed on the raw materials. In the experiments, the effect...
This paper presents the experimental testing and simulation results of ballistic impact tests on laminated armor samples that consist of three layers of different materials: fiber-cement, Kevlar fabric, and steel. In experimental tests, a 9 mm FMJ bullet was launched towards a 100 cm ² sample of the armor from the fiber-cement side. Ansys Workbench...
As the form factor of microelectronic systems and chips are continuing to shrink, the
demand for increased connectivity and functionality shows an unabated rising trend.
This is driving the evolution of technologies that requires 3D approaches for the integration
of devices and system design. The 3D technology allows higher packing densities as
wel...
Fuel Cell?
• Motivation
• Challenges for FC commercialization
• Focus of our study
• Introduction – Bipolar plates
• Novel design
• Experimental results
• Conclusions
This present study was carried out to check the feasibility of different cellulose fibers obtained from cropped virgin cellulose, blenched eucalyptus, and araucaria pulps through different new environmentally friendly curing processes for fiber-cement production. The aim is to introduce the different sources of cellulose fibers with lower cost to p...
Nanopowders of copper indium diselenide were produced with five different organic solvents: ethylenediamine, triethanolamine, oleylamine, oleic acid, and polyetheramine. We successfully synthesized pure CIS nanopowders at a temperature of 240°C at three different durations of 10 h, 20 h, and 40 h with a one-step process. This shorter time method of...
Organic photovoltaics (OPVs) are considered as a future alternative for conventional silicon based solar cells, owing to their low cost, ease of production and high-throughput. The transparent conducting electrode (TCE) is a fundamental component of OPVs. Traditionally, indium tin oxide (ITO) has been mainly utilized as a TCE in OPV applications du...
Standard connections from the probe head to the PCB for vertical type probe cards in wafer test are individual separate wires in space transformers (STs), traditionally used for device pitches 80 µm and above for quick turn inexpensive solutions compared to multilayer ceramic substrates. There are inherent signal integrity issues using separate wir...
Laser monitoring (remote sensing) may be considered as the science of collecting and interpreting information about the atmosphere, earth and sea using sensors on earth, on platforms in our atmosphere (airplanes, balloons) or in space (satellites) without being in direct physical contact with them. Remote sensing by LIDARs (Light Identification Det...
In this research, we investigated the influence of the surface coatings of silver nanowires on the sensitivity of surface acoustic wave (SAW) humidity sensors. Silver nanowires, with poly(vinylpyrrolidone) (PVP), which is a hydrophilic capping agent, were chemically synthesized, with an average length of 15 µm and an average diameter of 60 nm. Humi...
A novel electroplating system and approach for selectively coating of probe tips for wafer and package testing are presented. A Ni-alloy probe tip with an overcoat layer of 3.5um thick PdCo provided less tip wear and better electrical contact resistance performance in wafer testing. Microstructures of films resulting from different conditions of el...
Polymer electrolyte Membrane (PEM) fuel cell is an electrochemical device producing electricity by the reaction of hydrogen and oxygen without combustion. PEM fuel cell stack is provided with an appropriate clamping torque to prevent leakage of reactant gases and to minimize the contact resistance between gas diffusion media (GDL) and bipolar plate...
Nanoparticles of layered GaSe, InSe were fabricated by laser ablation (LA) method (KrF laser, λ = 248 nm, 50 Hz, maximum energy 200 mJ, τ = 4 ns) and characterized by: •XRF; •GDOES; •SEM and TEM; •UV-, VIS-, and IRabsorption; •Raman and PL spectroscopy (also in confocal geometry). Results are discussed in relation to the particle size. Absorption s...
Polymer exchange membrane fuel cells (PEMFC) are the devices that directly convert Chemical energy into Electrical energy and are potential candidates for portable and stationary power supply applications due to their several advantages over combustion engines. Among several challenges, cost and weight of PEMFC are prominent factors to be controlle...
A power delivery model of a probe test system used in wafer testing is presented. Designs for critical components contributing to voltage drop in the system including the PCB, the interposer the space transformer, vertical-type MEMS-based probes along with the contact resistance (CRes) were analyzed. Simulation results show that a reduction of 38%...
The probing test is a typical quality control method for individual chips on a wafer. This study investigates the cantilever wafer probe current carrying capacity along a probe body in order to model the probe burn phenomenon by using experimental techniques and numerical simulation. The standard measurement approach used in the test industry is co...
This paper investigates transient heat transfer between a heated spring probe and its air environment. A continuum finite volume simulation is used to analyze of heat flow within and from the resistively heated probe to its environment. Experimental results are conducted for spring probe with laminar air flow and without air flow. The numerical res...
Novel spring contactors were designed and characterized for wafer-level interposer and high-speed package test system applications, especially for wafer-level packages. These contactors can be used as replacement for vertical wafer probes as well as test sockets used in the final test. The contactor pin consists of a plunger section made of berylli...
The solar cells using silicon technology have been modeled and fabricated reaching 19% cell efficiency in the past. In an effort to maximize efficiency and reduce cost to reach the grid parity, thin films of silicon are being investigated. In this study, a solar cell hetero-junction with an intrinsic thin layer (HIT) was simulated on a p-type subst...
In an embodiment, a modular space transformer for use in a probe card assembly includes a bottom plate, a guide plate, and a top plate. The guide plate is configured for mounting in a cut-out of the bottom plate. The guide plate has a first surface and a second surface and additionally has a first plurality of spaced electrical connections disposed...
This study investigates the wafer probe temperature distribution along a probe body in order to model probe burn phenomenon by using computational mechanics techniques. The finite volume software is used to study the effects of different materials and different geometrical factors on the temperature along a special design vertical/spring and cantil...
Novel anode nanopowder materials consisting of ceria-based components synthesized by glycine-nitrate process were investigated for solid oxide fuel cells. Glycine-nitrate process involves a self-combustion reaction at 220°C of water-based nitrate and glycine solutions which subsequently can reach up to 1200°C. The resulting morphology, the size of...
Using a copper pillar interconnect in flip chip packaging provides a lead-free solution that is more reliable, and also scalable to very fine pitch. Vertical probe card technology, also called buckling beam technology, was used in characterization of wafer probe process and electrical contact on solder bumps and copper pillars at 150 $\mu{\rm m}$ p...
A method was developed for the deposition and annealing of Ni-alloy layers to obtain a low-stress film required for high cycle wafer probe applications. Ni-alloy layers with uniform compositions from 0.145 to 0.357 wt.% of Mn were electrodeposited. A high strength alloy with good ductility was produced using pulsed plating with a low internal stres...
Reliability in wafer test is critical for sort yield and the probe life is key to sort the floor performance. Probes made of Ni-alloys are becoming common as increasing parallelism and fine pitch requirements in test transform probe cards into microelectromechanical system products. NiMn probes, with a composition of 0.25 wt Mn and good spring prop...
An improved design for a blade utilised in a probe card is presented. The comparison is made with a current blade design and prototype test cards were manufactured for the study. Measurement results on S-parameters are reported on test cards with the new design and new blade material.
Submicron and nanocrystalline grain sizes were achieved in the A1203-ZrO2 eutectic composition through conventional, microwave and plasma sintering of rapidly solidified starting powders and through shock compaction of commercial powders. Post sintering studies revealed nanocrystalline intragranular ZrO2 in the 1-2 pm A1 2 0 3 grains, which is thou...
Shock compaction of Al2O3-ZrO3 binary and ternary powder compositions resulted in dense, one-piece samples without visible cracks for pressures ≤12.6 GPa. Dynamic pressures were achieved by using a 6.5-m-long two-stage gas gun. It is believed that plastic deformation by dislocation slip of α-Al2O3 partially accommodates the tensile stresses created...
We report on the phase transformation behavior of Pb0.91La0.09Zr0.65Ti0.35O3 (9/65/35) PLZT films grown on r-sapphire substrates via rf-magnetron sputtering. A complex microstructure results in these films depending on deposition and annealing conditions. A random equiaxed polycrystalline grain morphology was observed after rapid thermal annealing...
The transformation to perovskite phase of Pb0.91La0.09Zr0.65Ti0.35O3 (9/65/35) films on r-sapphire and resulting annealed microstructures were examined by transmission electron microscopy. A random equiaxed polycrystalline grain morphology (approximately 600 nm) was observed after rapid-thermal annealing or furnace annealing when the as-deposited (...
Homogeneous KTN (Potassium Tantalate Niobate) solutions were prepared using potassium acetate and metal alkoxides in 2-methoxyethanol by controlled hydrolysis with 1:2 (KTN/H2O) molar ratio. We report on the synthesis of sol-gel KTN for both the fabrication of homogeneous, dense and stoichiometrically correct ceramic discs by hot isostatic pressing...
The pyrochlore to perovskite phase transformation in PLZT 9/65/35 (Lead-lanthanum-zirconate-titanate) films are considered to be diffusion-controlled and the activation energy required for the formation of perovskite phase was determined to be 322 +- 48 kJ/mol.
The microstructural development and crystal structures of sputtered PLZT 9/65/35 films on r-plane sapphire with respect to deposition/annealing conditions were studied. The films were deposited at substrate temperatures below 500°C and annealed in the range 700° to 730°C for 1 min to 20 min for complete perovskite formation either by rapid thermal...
Lead lanthanum zirconate titanate (PLZT) thin films were deposited on r-plane sapphire at low temperatures by RF triode magnetron sputtering using lead compensated hot-pressed targets. To obtain fully perovskite phase in the films, two types of post-deposition processing were investigated: rapid thermal annealing (RTA) and furnace annealing (FA). D...
The use of integrable ferroelectric electro-optic thin films is a
revolutionary approach in the development of high-speed, low-voltage and
high-contrast ratio integrated electro-optic spatial light modulators
(SLM) for free-space optoelectronic interconnects. Thin films offer
improved performance over bulk ferroelectric (FE) materials because of
th...
Lead lanthanum zirconate titanate, PLZT (9/65/35) thin films were
deposited on r-plane sapphire and Pt/Si by triode-magnetron sputtering
at low temperature and transformed to the perovskite phase by
rapid-thermal annealing. To form perovskite phase directly during
deposition requires high substrate temperatures which generally cause
lead and/or tit...
The Al2O3-ZrO2 eutectic composition was rapidly solidified, forming amorphous and crystalline structures. The as-quenched material was crushed and pressed into pellets which were sintered conventionally or with microwaves. Conventional and microwave sintering at temperatures up to 1600 °C resulted in a microstructure where 100–200 nm ZrO2 grains we...
Shock compaction of Al[sub 2]O[sub 3]-ZrO[sub 2] binary and ternary powder compositions resulted in dense, one-piece samples without visible cracks for pressures [le]12.6 GPa. Dynamic pressures were achieved by using a 6.5-m-long two-state gas gun. It is believed that plastic deformation by dislocation slip of [alpha]-Al[sub 2]O[sub 3] partially ac...
The eutectic in the Al2O3-ZrO2 system was rapidly solidified by heating with an O2-H2 torch and then quenching the melt with a twin roller device. The as-quenched material, which was amorphous or nanocrystalline, was milled with B4C or Al2O3 media and pressed into pellets which were sintered conventionally or with microwaves. Samples contaminated w...
The eutectic in the AlâOâ-ZrOâ system was rapidly solidified by heating with an 0â-Hâ torch and then quenching the melt with a twin roller device. The as-quenched material, which was amorphous or nanocrystalline, was milled with BâC or Alâ0â media and pressed into pellets which were sintered conventionally or with microwaves. Samples contaminated w...