Eszter Horváth | BME - Academia.edu (original) (raw)
Papers by Eszter Horváth
Production Engineering Archives, 2020
In the recent years, additive manufacturing became an interesting topic in many fields due to the... more In the recent years, additive manufacturing became an interesting topic in many fields due to the ease of manufacturing complex objects. However, it is impossible to determine the mechanical properties of any additive manufacturing parts without testing them. In this work, the mechanical properties with focus on ultimate tensile strength and modulus of elasticity of 3D printed acrylonitrile butadi-ene styrene (ABS) specimens were investigated. The tensile tests were carried using Zwick Z005 loading machine with a capacity of 5KN according to the American Society for Testing and Materials (ASTM) D638 standard test methods for tensile properties of plastics. The aim of this study is to investigate the influence of printing direction on the mechanical properties of the printed specimens. Thus, for each printing direction ( and ), five specimens were printed. Tensile testing of the 3D printed ABS specimens showed that the printing direction made the strongest specimen at an ultimate ten...
Annual Research & Review in Biology, 2021
Cranioplasty is a surgery used to repair a bone defect in the skull caused by an injury. It invol... more Cranioplasty is a surgery used to repair a bone defect in the skull caused by an injury. It involves lifting the scalp and restoring the contour of the skull with an implant usually manufactured by additive manufacturing. The cranial implant is a sensitive topic; thus, it must be manufactured to the highest standards. Medical implants are growing significantly due to industrial digitalization and the rapid development of industrial software. With the help of computed Tomography (CT) equipment, a spatial, rotating model of the patient's current state can be obtained quickly, even in minutes where the replacement part of the deficiency can be perfectly designed. Although this requires considerable routine, computational capacity, and time, but taking advantage of the latest software presented in our manuscript, the development time of the implant can be up to 50 times shorter with significant improvements in suitability and adaptability. Subsequently, we can produce more accurate ...
Periodica Polytechnica Electrical Engineering, 2010
The processing of starch powder and polymer based sacrificial layer for fabrication of microfluid... more The processing of starch powder and polymer based sacrificial layer for fabrication of microfluidic structures in low temperature co-fired ceramics (LTCC) is described in the paper. Sacrificial volume material (SVM) was placed into the channel of LTCC sheets to avoid sagging by supporting embedded, three-dimensional structures such as channels, cavities during firing. Sagging of laminated structures is a common problem in the processing of the LTCC. A series of experiments were carried out for different lamination schemes which affect the quality of LTCC sheets. Samples were tested by an acoustic microscope to reveal the internal inhomogeneities and delaminations. As a consequence of burnout, the increased fraction of evolving gases from SVM requires an adequate adaptation of the firing process to provide a residue-free burnout without damaging the structure. Using thermal analysis the intensity of the evaporating gases was determined during co-firing. Based on these results, the modification of the heating profile could be done. It is proposed that the fabrication of embedded structures in a multi-layer LTCC platform could be achieved by controlling SVM burnout with a modified heating profile. Using this approach, fabrication of embedded channels in LTCC substrate is demonstrated.
Journal of Materials Science: Materials in Electronics, 2012
The mechanical behaviour of implantable scaffolds is of relevant interest in all applications whi... more The mechanical behaviour of implantable scaffolds is of relevant interest in all applications which require load-bearing capability. This study aims at establishing a quantitative relationship between the mechanical properties of glass-ceramic scaffolds for bone repair and the nano/micro-scale properties of their constituent materials. A nanoindentation study is carried out spanning different penetration depth on bulk (pore-free) glass-ceramic samples and on the walls of porous scaffolds. Micro-tomographical investigations allow assessing small-scale porosity of the scaffold walls. A simple homogenization model is used to establish the relationship between the elastic modulus of the bulk material and that of the microporous walls of the scaffolds. The elastic modulus of scaffold walls was found to be approximately 50% lower than that of the bulk glass-ceramic. The properties estimated experimentally on the walls of the scaffolds are quantitatively consistent with the analytical predictions provided by the homogenization model and the micro-porosity measured through tomographical analyses.
Transport, 2013
Nowadays low temperature co-fired ceramics (further on: LTCC) are used in sensor technology as se... more Nowadays low temperature co-fired ceramics (further on: LTCC) are used in sensor technology as sensors and actuators. Sensors and actuators are playing an important role in intelligent road vehicles. These sensors and actuators are built up by LTCC Microsystems. The processing of starch powder and polymer based on sacrificial layer for fabrication of microfluidic structures of LTCC is described in this paper. In order to determine the optimal lamination parameters the quality of the structure was examined for 30 different temperature-pressure-time adjustments. Samples were examined by scanning acoustic microscope to detect the subsurface delamination and internal inhomogenities. The acoustic microscopic image of each sample from different lamination method was evaluated by image processing algorithm in MATLAB environment.
Periodica Polytechnica Electrical Engineering, 2008
The materials that are used to create low temperature cofired ceramics (LTCC) circuits (produced ... more The materials that are used to create low temperature cofired ceramics (LTCC) circuits (produced from green tape and various pastes) can be processed by the equipment of the conventional thick-film technology (screen printing machine, drying and burning ovens). The equipment needed to produce multilayer boards (sinter press, tools, punching machine or Nd-YAG laser) can be purchased with a little investment. At the same time the high temperature co-fired ceramics (HTCC) technology requires completely new equipment, so the changeover is harder and more expensive. An LTCC test-circuit was designed and realized by using the thick-film technology equipment at the Department of Electronics Technology, BME. The surface and embedded resistors were made from thick-film paste. In the course of the realization and with circuit measurements it could be determined what have to be considered at the pre-calculation of the resistor values. Keywords LTCC manufacturing • thick-film • embedded resistor • glass ceramics Acknowledgement I would like to express my many thanks to my consultants Gábor Harsányi and Gábor Ripka for their help in writing this article. I am deeply grateful to Csaba Gyenes and Szilárd Szöllősi for their furthersome contribution in the experimental measurements and constructions. Thank DuPont for utilizing the compositions.
Brain Research Protocols, 2003
We developed a new neural transplantation protocol for the investigation of the repair of brain t... more We developed a new neural transplantation protocol for the investigation of the repair of brain trauma. Cortical lesion was induced by touching a cold (-60 degrees C) metal stamp to the dura over the forelimb motor cortex of adult rats. The procedure caused a localized lesion and the animals developed a significant motor deficit, which was monitored throughout the protocol. Six days later the animals received embryonic neural stem cells in the penumbra of the lesion. The donor cells were freshly isolated from E14 rat embryos, had a high viability, and expressed the stem cell marker nestin. A further 6 days later the survival and differentiation of the grafted cells were investigated by immunohistochemistry. The majority of the surviving grafted cells were found in the lesion and they did not express lineage-specific markers. Only 10% of all surviving transplanted cells were located in the penumbra. These cells had an astrocytic phenotype and expressed glial fibrillary acidic protein. A few cells expressed neural or oligodendrocytic markers. In conclusion, we established a novel neural transplantation protocol, which focuses on cortical brain trauma. The model is a combination of surgical, neurological and histological approaches, all adapted to each other to make a reliable and reproducible experimental model.
Production Engineering Archives, 2020
In the recent years, additive manufacturing became an interesting topic in many fields due to the... more In the recent years, additive manufacturing became an interesting topic in many fields due to the ease of manufacturing complex objects. However, it is impossible to determine the mechanical properties of any additive manufacturing parts without testing them. In this work, the mechanical properties with focus on ultimate tensile strength and modulus of elasticity of 3D printed acrylonitrile butadi-ene styrene (ABS) specimens were investigated. The tensile tests were carried using Zwick Z005 loading machine with a capacity of 5KN according to the American Society for Testing and Materials (ASTM) D638 standard test methods for tensile properties of plastics. The aim of this study is to investigate the influence of printing direction on the mechanical properties of the printed specimens. Thus, for each printing direction ( and ), five specimens were printed. Tensile testing of the 3D printed ABS specimens showed that the printing direction made the strongest specimen at an ultimate ten...
Annual Research & Review in Biology, 2021
Cranioplasty is a surgery used to repair a bone defect in the skull caused by an injury. It invol... more Cranioplasty is a surgery used to repair a bone defect in the skull caused by an injury. It involves lifting the scalp and restoring the contour of the skull with an implant usually manufactured by additive manufacturing. The cranial implant is a sensitive topic; thus, it must be manufactured to the highest standards. Medical implants are growing significantly due to industrial digitalization and the rapid development of industrial software. With the help of computed Tomography (CT) equipment, a spatial, rotating model of the patient's current state can be obtained quickly, even in minutes where the replacement part of the deficiency can be perfectly designed. Although this requires considerable routine, computational capacity, and time, but taking advantage of the latest software presented in our manuscript, the development time of the implant can be up to 50 times shorter with significant improvements in suitability and adaptability. Subsequently, we can produce more accurate ...
Periodica Polytechnica Electrical Engineering, 2010
The processing of starch powder and polymer based sacrificial layer for fabrication of microfluid... more The processing of starch powder and polymer based sacrificial layer for fabrication of microfluidic structures in low temperature co-fired ceramics (LTCC) is described in the paper. Sacrificial volume material (SVM) was placed into the channel of LTCC sheets to avoid sagging by supporting embedded, three-dimensional structures such as channels, cavities during firing. Sagging of laminated structures is a common problem in the processing of the LTCC. A series of experiments were carried out for different lamination schemes which affect the quality of LTCC sheets. Samples were tested by an acoustic microscope to reveal the internal inhomogeneities and delaminations. As a consequence of burnout, the increased fraction of evolving gases from SVM requires an adequate adaptation of the firing process to provide a residue-free burnout without damaging the structure. Using thermal analysis the intensity of the evaporating gases was determined during co-firing. Based on these results, the modification of the heating profile could be done. It is proposed that the fabrication of embedded structures in a multi-layer LTCC platform could be achieved by controlling SVM burnout with a modified heating profile. Using this approach, fabrication of embedded channels in LTCC substrate is demonstrated.
Journal of Materials Science: Materials in Electronics, 2012
The mechanical behaviour of implantable scaffolds is of relevant interest in all applications whi... more The mechanical behaviour of implantable scaffolds is of relevant interest in all applications which require load-bearing capability. This study aims at establishing a quantitative relationship between the mechanical properties of glass-ceramic scaffolds for bone repair and the nano/micro-scale properties of their constituent materials. A nanoindentation study is carried out spanning different penetration depth on bulk (pore-free) glass-ceramic samples and on the walls of porous scaffolds. Micro-tomographical investigations allow assessing small-scale porosity of the scaffold walls. A simple homogenization model is used to establish the relationship between the elastic modulus of the bulk material and that of the microporous walls of the scaffolds. The elastic modulus of scaffold walls was found to be approximately 50% lower than that of the bulk glass-ceramic. The properties estimated experimentally on the walls of the scaffolds are quantitatively consistent with the analytical predictions provided by the homogenization model and the micro-porosity measured through tomographical analyses.
Transport, 2013
Nowadays low temperature co-fired ceramics (further on: LTCC) are used in sensor technology as se... more Nowadays low temperature co-fired ceramics (further on: LTCC) are used in sensor technology as sensors and actuators. Sensors and actuators are playing an important role in intelligent road vehicles. These sensors and actuators are built up by LTCC Microsystems. The processing of starch powder and polymer based on sacrificial layer for fabrication of microfluidic structures of LTCC is described in this paper. In order to determine the optimal lamination parameters the quality of the structure was examined for 30 different temperature-pressure-time adjustments. Samples were examined by scanning acoustic microscope to detect the subsurface delamination and internal inhomogenities. The acoustic microscopic image of each sample from different lamination method was evaluated by image processing algorithm in MATLAB environment.
Periodica Polytechnica Electrical Engineering, 2008
The materials that are used to create low temperature cofired ceramics (LTCC) circuits (produced ... more The materials that are used to create low temperature cofired ceramics (LTCC) circuits (produced from green tape and various pastes) can be processed by the equipment of the conventional thick-film technology (screen printing machine, drying and burning ovens). The equipment needed to produce multilayer boards (sinter press, tools, punching machine or Nd-YAG laser) can be purchased with a little investment. At the same time the high temperature co-fired ceramics (HTCC) technology requires completely new equipment, so the changeover is harder and more expensive. An LTCC test-circuit was designed and realized by using the thick-film technology equipment at the Department of Electronics Technology, BME. The surface and embedded resistors were made from thick-film paste. In the course of the realization and with circuit measurements it could be determined what have to be considered at the pre-calculation of the resistor values. Keywords LTCC manufacturing • thick-film • embedded resistor • glass ceramics Acknowledgement I would like to express my many thanks to my consultants Gábor Harsányi and Gábor Ripka for their help in writing this article. I am deeply grateful to Csaba Gyenes and Szilárd Szöllősi for their furthersome contribution in the experimental measurements and constructions. Thank DuPont for utilizing the compositions.
Brain Research Protocols, 2003
We developed a new neural transplantation protocol for the investigation of the repair of brain t... more We developed a new neural transplantation protocol for the investigation of the repair of brain trauma. Cortical lesion was induced by touching a cold (-60 degrees C) metal stamp to the dura over the forelimb motor cortex of adult rats. The procedure caused a localized lesion and the animals developed a significant motor deficit, which was monitored throughout the protocol. Six days later the animals received embryonic neural stem cells in the penumbra of the lesion. The donor cells were freshly isolated from E14 rat embryos, had a high viability, and expressed the stem cell marker nestin. A further 6 days later the survival and differentiation of the grafted cells were investigated by immunohistochemistry. The majority of the surviving grafted cells were found in the lesion and they did not express lineage-specific markers. Only 10% of all surviving transplanted cells were located in the penumbra. These cells had an astrocytic phenotype and expressed glial fibrillary acidic protein. A few cells expressed neural or oligodendrocytic markers. In conclusion, we established a novel neural transplantation protocol, which focuses on cortical brain trauma. The model is a combination of surgical, neurological and histological approaches, all adapted to each other to make a reliable and reproducible experimental model.