Papers by Vlad-Alexandru Grosu
Nanomaterials
Composite membranes play a very important role in the separation, concentration, and purification... more Composite membranes play a very important role in the separation, concentration, and purification processes, but especially in membrane reactors and membrane bioreactors. The development of composite membranes has gained momentum especially through the involvement of various nanoparticles, polymeric, oxide, or metal, that have contributed to increasing their reactivity and selectivity. This paper presents the preparation and characterization of an active metal nanoparticle-support polymer type composite membrane, based on osmium nanoparticles obtained in situ on a polypropylene hollow fiber membrane. Osmium nanoparticles are generated from a solution of osmium tetroxide in tert-butyl alcohol by reduction with molecular hydrogen in a contactor with a polypropylene membrane. The composite osmium-polypropylene hollow fiber obtained membranes (Os-PPM) were characterized from the morphological and structural points of view: scanning electron microscopy (SEM), high resolution SEM (HR-SEM)...
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MDPI Membranes, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY)
Membranes are associated with the efficient processes of separation, concentration and purification, but a very important aspect of them is the realization of a reaction process simultaneously with the separation process. From a practical point of view, chemical reactions have been introduced in most membrane systems: with on-liquid membranes, with inorganic membranes or with polymeric and/or composite membranes. This paper presents the obtaining of polymeric membranes containing metallic osmium obtained in situ. Cellulose acetate (CA), polysulfone (PSf) and polypropylene hollow fiber membranes (PPM) were used as support polymer membranes. The metallic osmium is obtained directly onto the considered membranes using a solution of osmium tetroxide (OsO4), dissolved in tert–butyl alcohol (t–Bu–OH) by reduction with molecular hydrogen. The composite osmium–polymer (Os–P)-obtained membranes were characterized in terms of the morphological and structural points of view: scanning electron microscopy (SEM), high-resolution SEM (HR–SEM), energy-dispersive spectroscopy analysis (EDAX), Fourier Transform Infra-Red (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The process performance was tested for reduction of 5–nitrobenzimidazole to 5–aminobenzimidazole with molecular hydrogen. The paper presents the main aspects of the possible mechanism of transformation of 5–nitrobenzimidazole to 5–aminobenzimidazole with hydrogen gas in the reaction system with osmium–polymer membrane (Os–P)
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MDPI Membranes, 2021
The membranes and membrane processes have succeeded in the transition from major technological an... more The membranes and membrane processes have succeeded in the transition from major technological and biomedical applications to domestic applications: water recycling in washing machines, recycling of used cooking oil, recovery of gasoline vapors in the pumping stations or enrichment of air with oxygen. In this paper, the neutralization of condensation water and the retention of aluminum from thermal power plants is studied using ethylene propylene diene monomer sulfonated (EPDM-S) membranes containing magnetic particles impregnated in a microporous propylene hollow fiber (I-PPM) matrix. The obtained membranes were characterized from the morphological and structural points of view, using scanning electron microscopy (SEM), high resolution SEM (HR-SEM), energy dispersive spectroscopy analysis (EDAX) and thermal gravimetric analyzer. The process performances (flow, selectivity) were studied using a variable magnetic field generated by electric coils. The results show the possibility of correcting the pH and removing aluminum ions from the condensation water of heating plants, during a winter period, without the intervention of any operator for the maintenance of the process. The pH was raised from an acidic one (2–4), to a slightly basic one (8–8.5), and the concentration of aluminum ions was lowered to the level allowed for discharge. Magnetic convection of the permeation module improves the pH correction process, but especially prevents the deposition of aluminum hydroxide on hollow fibers membranes.
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Sensors
This paper describes the steps involved in obtaining a set of relevant data sources and the accom... more This paper describes the steps involved in obtaining a set of relevant data sources and the accompanying method using software-based sensors to detect anomalous behavior in modern smartphones based on machine-learning classifiers. Three classes of models are investigated for classification: logistic regressions, shallow neural nets, and support vector machines. The paper details the design, implementation, and comparative evaluation of all three classes. If necessary, the approach could be extended to other computing devices, if appropriate changes were made to the software infrastructure, based upon mandatory capabilities of the underlying hardware.
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Periodicals of Engineering and Natural Sciences (PEN)
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Periodicals of Engineering and Natural Sciences (PEN)
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Proceedings of the 9th Wseas International Conference on Advances in E Activities Information Security and Privacy, Dec 14, 2010
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International Journal of Information Security and Cybercrime, 2013
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CAS 2011 Proceedings (2011 International Semiconductor Conference), 2011
Autonomous weather monitoring applications, especially the distributed ones, implies low power co... more Autonomous weather monitoring applications, especially the distributed ones, implies low power consumption both for sensors and computing/storage facilities. Making the autonomous system more efficient requires optimizing consumption for the computing and storage facilities are they require more energy to function than the sensors. Modern embedded systems are a solution, as they have to continuously balance the need for increased performance,
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In this article I use a symmetrical cryptographic method based on symbols transposition: Hill's c... more In this article I use a symmetrical cryptographic method based on symbols transposition: Hill's cipher. This consists in a symmetrical approach based on 'modulo m' arithmetic. The theory says that one has to choose a prime number as the length of the modulo-m space used. Nevertheless, based on my conclusions here, this choice is not mandatory. As a proof of concept for the supportive case study, I chose a computational medium based on a system-on-chip solution offered by Texas Instruments, namely Beagleboard. The main purpose is to emphasize the original concepts that I introduced along my PhD thesis, 'self-recognition' and 'symmetrical copy'. The data
restoration operation that accompanies the set of compression/ decompression operations that I proposed requires the generation of a file called 'symmetrical copy'.
The overall details of the above mentioned new concepts can be found in my PhD thesis - "Real-time compression/decompression algorithms applied to embedded systems".
That very practical context is one of the possible situations within which Hill's cipher still suits.
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A set of recovery techniques is presented here, for special
computational working contexts as tho... more A set of recovery techniques is presented here, for special
computational working contexts as those for the embedded
systems. A novelty restoration technique, thought for
embedded systems, is presented here. The comparison is
made against Java Archive (.jar) often used for such
computational media. The most representative example in
this class is the smart mobile terminals, also known as
smartphones. For such a medium, there is a software
solution that relies upon a Java virtual machine and
extensively uses .jar file type that powers a large area of
smartphones: Android operating system. A new data
compression/decompression technique is introduced here,
that deals especially with decompression time. This new
compression method also comes with a restoration option for
corrupted archive .zha files, based on the 'symmetrical
copy'. Basically the symmetrical copy is based on a
symmetrical encryption based on the transposition of
symbols, namely Hill's cipher. Both the data restoration
idea and the phrases 'symmetrical copy' along with the
related 'self recognition' are all original. One can find
details upon this in my PhD thesis, ”Real-time
compression/decompression algorithms for embedded
systems”, held at Politehnica University in Bucharest,
within the Electronics Technology and Reliability
department of Electronics, Telecommunications and
Information Technology faculty.
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Conference Presentations by Vlad-Alexandru Grosu
SISOM symposium, 2017
This paper presents the extended techniques used in Spline interpolation for serial robotic manip... more This paper presents the extended techniques used in Spline interpolation for serial robotic manipulators. The new algorithms are meant to improve the motion stability for robotic joints with applications in walking and hybrid robots. The movement computation will be integrated into an interactive interface, as part of a versatile intelligent robotic platform. The obtained results show great opportunities for further development using a wide array of adaptive computational strategies.
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Papers by Vlad-Alexandru Grosu
Membranes are associated with the efficient processes of separation, concentration and purification, but a very important aspect of them is the realization of a reaction process simultaneously with the separation process. From a practical point of view, chemical reactions have been introduced in most membrane systems: with on-liquid membranes, with inorganic membranes or with polymeric and/or composite membranes. This paper presents the obtaining of polymeric membranes containing metallic osmium obtained in situ. Cellulose acetate (CA), polysulfone (PSf) and polypropylene hollow fiber membranes (PPM) were used as support polymer membranes. The metallic osmium is obtained directly onto the considered membranes using a solution of osmium tetroxide (OsO4), dissolved in tert–butyl alcohol (t–Bu–OH) by reduction with molecular hydrogen. The composite osmium–polymer (Os–P)-obtained membranes were characterized in terms of the morphological and structural points of view: scanning electron microscopy (SEM), high-resolution SEM (HR–SEM), energy-dispersive spectroscopy analysis (EDAX), Fourier Transform Infra-Red (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The process performance was tested for reduction of 5–nitrobenzimidazole to 5–aminobenzimidazole with molecular hydrogen. The paper presents the main aspects of the possible mechanism of transformation of 5–nitrobenzimidazole to 5–aminobenzimidazole with hydrogen gas in the reaction system with osmium–polymer membrane (Os–P)
restoration operation that accompanies the set of compression/ decompression operations that I proposed requires the generation of a file called 'symmetrical copy'.
The overall details of the above mentioned new concepts can be found in my PhD thesis - "Real-time compression/decompression algorithms applied to embedded systems".
That very practical context is one of the possible situations within which Hill's cipher still suits.
computational working contexts as those for the embedded
systems. A novelty restoration technique, thought for
embedded systems, is presented here. The comparison is
made against Java Archive (.jar) often used for such
computational media. The most representative example in
this class is the smart mobile terminals, also known as
smartphones. For such a medium, there is a software
solution that relies upon a Java virtual machine and
extensively uses .jar file type that powers a large area of
smartphones: Android operating system. A new data
compression/decompression technique is introduced here,
that deals especially with decompression time. This new
compression method also comes with a restoration option for
corrupted archive .zha files, based on the 'symmetrical
copy'. Basically the symmetrical copy is based on a
symmetrical encryption based on the transposition of
symbols, namely Hill's cipher. Both the data restoration
idea and the phrases 'symmetrical copy' along with the
related 'self recognition' are all original. One can find
details upon this in my PhD thesis, ”Real-time
compression/decompression algorithms for embedded
systems”, held at Politehnica University in Bucharest,
within the Electronics Technology and Reliability
department of Electronics, Telecommunications and
Information Technology faculty.
Conference Presentations by Vlad-Alexandru Grosu
Membranes are associated with the efficient processes of separation, concentration and purification, but a very important aspect of them is the realization of a reaction process simultaneously with the separation process. From a practical point of view, chemical reactions have been introduced in most membrane systems: with on-liquid membranes, with inorganic membranes or with polymeric and/or composite membranes. This paper presents the obtaining of polymeric membranes containing metallic osmium obtained in situ. Cellulose acetate (CA), polysulfone (PSf) and polypropylene hollow fiber membranes (PPM) were used as support polymer membranes. The metallic osmium is obtained directly onto the considered membranes using a solution of osmium tetroxide (OsO4), dissolved in tert–butyl alcohol (t–Bu–OH) by reduction with molecular hydrogen. The composite osmium–polymer (Os–P)-obtained membranes were characterized in terms of the morphological and structural points of view: scanning electron microscopy (SEM), high-resolution SEM (HR–SEM), energy-dispersive spectroscopy analysis (EDAX), Fourier Transform Infra-Red (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The process performance was tested for reduction of 5–nitrobenzimidazole to 5–aminobenzimidazole with molecular hydrogen. The paper presents the main aspects of the possible mechanism of transformation of 5–nitrobenzimidazole to 5–aminobenzimidazole with hydrogen gas in the reaction system with osmium–polymer membrane (Os–P)
restoration operation that accompanies the set of compression/ decompression operations that I proposed requires the generation of a file called 'symmetrical copy'.
The overall details of the above mentioned new concepts can be found in my PhD thesis - "Real-time compression/decompression algorithms applied to embedded systems".
That very practical context is one of the possible situations within which Hill's cipher still suits.
computational working contexts as those for the embedded
systems. A novelty restoration technique, thought for
embedded systems, is presented here. The comparison is
made against Java Archive (.jar) often used for such
computational media. The most representative example in
this class is the smart mobile terminals, also known as
smartphones. For such a medium, there is a software
solution that relies upon a Java virtual machine and
extensively uses .jar file type that powers a large area of
smartphones: Android operating system. A new data
compression/decompression technique is introduced here,
that deals especially with decompression time. This new
compression method also comes with a restoration option for
corrupted archive .zha files, based on the 'symmetrical
copy'. Basically the symmetrical copy is based on a
symmetrical encryption based on the transposition of
symbols, namely Hill's cipher. Both the data restoration
idea and the phrases 'symmetrical copy' along with the
related 'self recognition' are all original. One can find
details upon this in my PhD thesis, ”Real-time
compression/decompression algorithms for embedded
systems”, held at Politehnica University in Bucharest,
within the Electronics Technology and Reliability
department of Electronics, Telecommunications and
Information Technology faculty.