Cenk Kocer

• PhD
• Senior Researcher at The University of Sydney

This paper presents the first part of a study on the effect of wind loads on Vacuum Insulated Glass (VIG) units. The study provides background information on VIG and relevant Standards, explains the numerical modelling process, and discusses the implications of the results in relation to European and North American codes and Standards. The focus of...

Non-uniformities in the heat flow through the support pillars in vacuum insulating glass (VIG) can lead to significant errors in the measurement of the thermal insulating properties of these devices. This paper discusses these errors in instruments for which the measurement area is in direct thermal contact with the glass sheets. The spatial non-un...

This is the second of two papers concerning errors in the measurement of the thermal insulating properties of Vacuum Insulating Glass (VIG) due to non-uniformities in the heat flow due to the support pillars. Part 1 deals with the situation where the measurement area is in direct thermal contact with the glass sheets. This paper discusses how the n...

The Vacuum Insulated Glazing is a highly thermally insulating structure consisting of two (or more) glass sheets, separated by an evacuated gap, and sealed hermetically at the glass edges. An array of support pillars maintains the separation of the panes under the constant load of atmospheric pressure. The performance and durability of the VIG, in...

Vacuum insulated glazing (VIG) is a highly thermally insulating window technology, which boasts an extremely thin profile and lower weight as compared to gas-filled insulated glazing units of equivalent performance. The VIG is a double-pane configuration with a submillimeter vacuum gap maintained by small pillars positioned in between the panes, wh...

Das Interesse an Vakuumisolierglas (VIG), einer thermisch optimierten und dünneren Alternative zu herkömmlichen Mehrscheibenisoliergläsern, wächst. Während die jahrelange Optimierung der bauphysikalischen Eigenschaften bereits dazu führt, dass heute U g ‐Werte von unter 0,4 W/(m ² K) erreicht werden können, fehlen für das mechanische Verhalten dies...

This study presents in situ monitoring data of three different glazing systems over a period of one year. An insulated glass unit (IGU), a Vacuum Insulated Glass hybrid unit (VIG-hybrid) and an opaque architectural insulation module (AIM) were monitored under the equivalent environmental condition in this study. Different issues were observed and a...

Vacuum Insulated Glazing (VIG) is a highly thermally insulating window technology, which boasts an extremely thin profile and lower weight as compared to gas-filled insulated glazing units of equivalent performance. The VIG is a double-pane configuration with a submillimeter vacuum gap between the panes and therefore under constant atmospheric pres...

Soda-lime-silica glass is a widely used material in society today and its strength over various loading times is of major engineering concern. This paper reviews studies from the published literature, which report on the time-dependent tensile behaviour of soda-lime-silica glass. Furthermore, current normative definitions are reviewed and compared...

Thermal vacancies and vacancy complexes in solids have not been treated explicitly in the CALPHAD-type thermodynamic assessments. Since thermal vacancies have important roles in phase transformations, precipitations and diffusion processes, it is necessary to describe them in the thermodynamic models for various simulations e.g. phase field simulat...

The Gibbs energy functions of the phases in the Al-Cu binary system are taken from the CALPHAD-type thermodynamic assessment (Witusiewicz et al., 2004; Ansara et al., 1998) [1], [2], where the effect of the monovacancy (Va), divacancy (VaVa) and Va-solute atom pair are taken into account based on the formulation (Abe et al., In press). The divacanc...

Vacuum insulating glazing (VIG) is a relatively new glazing technology that was first developed primarily for its thermal insulation properties. This research aims to continue a preceding study about the acoustic performance of VIG and to analyse the effects of dissimilar thickness and additional damping to the sound insulation performance of VIG....

Graded Ti/C composite films with carbon topcoats are prepared on bendable stainless steel foils by hybrid cathodic arc / glow discharge plasma-assisted chemical vapor deposition to simulate cardiovascular stents. Strong adhesion between the stainless steel substrate and carbon topcoat is achieved due to the graded Ti/C interface and it is further i...

The mechanical behaviour of carbon films prepared with a variety of densities and microstructures was investigated using nanoindentation. Deposition energies between 25 and 600 eV and temperatures in the range 25–600 °C were used. Films prepared at low temperatures and moderate energies were amorphous with a high density. Finite element methods wer...

For interstitial solid solutions various sublattice configurations have been applied in CALPHAD-type thermodynamic assessments. To construct a thermodynamic database for multi-component systems from the assessed binary and ternary systems, one difficulty is consistency of the thermodynamic models for those phases with sublattices. Previously, to co...

In this work the assessment of the Cr–Re system, using a combined ab initio and CALPHAD (CALculation of Phase Diagrams) approach, is presented. To model the sigma phase, a five-sublattice combined CEF model was applied and the present description reproduces reasonably well the previously published experimental phase diagram. Formation enthalpies of...

The formation enthalpies of the Z- and B1 MN-phases, where M = Cr, Fe, Nb, and V, were calculated using an ab initio computational method. The relative stability of the Z- and MN-phases was examined in the framework of the CALPHAD methodology. The analysis indicates that the Z-phase is more stable than the B1 MN-phase in the 9–12% Cr ferritic steel...

The theory of elasticity predicts a variety of phenomena associated with solids that possess a negative Poisson's ratio. The fabrication of metamaterials with a 'designed' microstructure that exhibit a Poisson's ratio approaching the thermodynamic limits of 1/2 and -1 increases the likelihood of realising these phenomena for applications. In this w...

In many large and small scale devices metal and glass are used side-by-side. In general, metal components are coupled directly to glass components to provide extra strength. However, in certain configurations the metal-glass interface is a structural weak point. This is particularly the case when the composite metal-glass systems are subjected to i...

The thermodynamic assessment of the Al–Ir binary system was performed using the CALPHAD technique. The B2-AlIr phase was described, using the two sublattice model with the formula (Al,Ir,V a)1/2(Al,Ir,V a)1/2, while Al9Ir2, Al3Ir, Al13Ir4, Al45Ir13, Al28Ir9, and Al2.7Ir compounds were treated as stoichiometric compounds. The fcc-based phases (L10-A...

Al-rich portion of the Ir–Al phase diagram has been investigated with 10 alloys by means of differential thermal analysis, X-ray diffraction, scanning electron microscopy, inductivity coupled plasma spectrometry and electron probe microanalysis. Invariant reactions are observed: L↔AlIr+Al2.7Ir, L+Al2.7Ir↔Al3Ir, L+Al3Ir↔Al13Ir4, L+Al13Ir4↔Al9Ir2. Al...

The thermodynamic assessment of the Al-Ir binary system, one of the key sub-systems of the Ir-based alloys, was performed using the CALPHAD technique. The AlIr(B2) phase was described using the two sublattice model with the formula (Al,Ir)0.5(Ir,Va)0.5, while other intermetallic phases were treated as stoichiometric compounds. The calculated data o...

The transition of diamond-like materials from an sp to sp rich state is of particular interest because of the desirable properties of tetrahedral amorphous carbon (ta-C). Previous works indicate that infrequent processes may dominate this transition, but simulation of these processes presents significant difficulties, since the infrequent processes...

This thin-film deposition study of tetrahedral amorphous carbon shows that including infrequent processes on the millisecond scale substantially improves the accuracy of molecular dynamics simulations. Elevated temperature between energetic impacts is used to activate processes which are typically ignored. In agreement with experiment, the simulati...

The mechanical behavior of the cubic spinel SiAlON polymorph (c-Si 6Àz Al z O z N 8Àz , z = 1), was modeled using an ab initio den-sity functional technique. The cubic spinel structure exhibits a maximum stress response of $33 and $40 GPa, for the applied c 11 and c 23 components of strain, respectively. An existing empirical technique was employed...

This paper describes the conception and design of a micropump for gas, with no moving or deformable parts, for use on the future sensor network system, which includes environment monitoring. This design is original because of the complete absence of moving parts for the pumping of gas. In fact, fluid movement was obtained by means of repetitive hea...

Following a brief review of the past work published on the structural and mechanical properties of the β-SiAlON crystal, an ab initio computational method is outlined, which was employed to investigate the material properties and electronic structure of the β-Si6−zAlzOzN8−z, where z=0–5, single crystal configuration. Using data of preferred lattice...

This paper discusses the difference between the experimentally observed angle of Hertzian cone cracks and the angle defined by the trajectories of the preexisting stress fields. It is argued that there is no reason why these angles should be the same, as has usually been assumed. A finite element method has been used to model the growth of cracks i...

The rate of very slow crack growth in glass is measured by inducing small, controllable changes in the direction of propagation of Hertzian cone cracks at known times. After completion of a growth sequence, the sample is sectioned to reveal the fracture surface. The stress intensity factor at each stage of crack growth is calculated by using finite...

A derivative of the Si3N4 ceramic is the quaternary SiAlON solid solution. In this paper the characteristic stress-strain response of the,Band c-SiAION phases is investigated using an ab initio computational procedure, for the gamma(11) strain component, where different substitutions of the atomic pairs, Al-O, were performed. From the modeled data...

A derivative of the Si 3 N 4 ceramic is the quaternary SiAlON solid solution. In this paper the characteristic stress-strain response of the -and c-SiAlON phases is investigated using an ab initio computational procedure, for the 11 strain component, where different substitutions of the atomic pairs, Al-O, were performed. From the modeled data the...

In this study, the ideal tensile and shear strengths of single crystal α- and β-Si3N4 were calculated using an ab initio density functional technique. The stress–strain curve of the silicon nitride polymorph was calculated from simulations of predefined strain deformation in various directions. In particular, the ideal strength calculated for an ap...

The Ln(2)O(3) rare-earth oxides, sesquioxides, in the lanthanide series are a group of compounds of particular importance, which are the most widespread lanthanide compounds generally used as a catalyst for the synthesis of many other 4f-materials. In this study, density functional theory was employed to calculate the equilibrium crystal lattice di...

In this study, the ideal tensile and shear strength of single-crystal β–Si3N4 was calculated using an ab initio density functional technique. The stress-strain curve of the silicon nitride polymorph was calculated from simulations of uniaxial strain deformation. In particular, the ideal strength calculated for an applied ∈11 tensile strain was esti...

In this study a novel finite element method is presented for modeling Hertzian cone crack growth. The method involves the automation of an existing incremental finite element technique. The local stress fields in the vicinity of the crack tip at each stage of growth of the crack are determined, and the crack is advanced by a small amount along the...

In this study, the ideal tensile and shear strength of the recently discovered cubic spinel silicon nitride polymorph was calculated using an ab initio density functional technique. The stress-strain curve of the cubic silicon nitride structure was calculated from simulations of applied ɛ11 and ɛ23 components of strain, and the ideal strengths were...

In order to describe better the probability of failure of structures, crack growth data of the underlying material is required. In particular, it is well known that to calculate accurately the probability of failure of a structure that has sustained low loads for long periods, crack growth data of very low rates of growth are necessary. There exist...

The molecular dynamics method was used to simulate energy transport in α- and β-Si3N4 single crystals. The simulation data, in conjunction with the Green-Kubo formulation, was used to calculate the thermal conductivity of the single crystals, as a function of temperature. Although a relatively small simulation supercell size was employed, the therm...

In this study, the ideal strength of β-silicon nitride was calculated using a first-principles molecular dynamics method. The stress-strain curve of β-silicon nitride was calculated from simulations of uniaxial extension in the [100] and [001] axial directions, and an ideal tensile strength of ∼72.2 and ∼75.0 GPa, respectively, was obtained. In add...