Quoc Hung Bui - Academia.edu (original) (raw)
Papers by Quoc Hung Bui
Modern Earth Buildings, 2012
ABSTRACT Durability of earthen structures is mainly dependent on the action of water on the walls... more ABSTRACT Durability of earthen structures is mainly dependent on the action of water on the walls. In this chapter, the relevance of the current tests measuring the resistance of earthen material to water is analysed and some pertinent tests are suggested to corresponding domains of application. The second part of the chapter deals with the use of plaster to increase durability. The validation of the plaster is proposed thanks to two in situ tests: the shrinkage test and the shear test for surface coatings. The long-term performance of earthen material is then analysed through research that has been conducted on walls exposed to natural climatic conditions for several years. Key words: durability, weathering, erosion, surface coatings
Advanced Materials Research, 2014
For purpose of synthesis new epoxy coatings to protect the structural steel in sea environment, i... more For purpose of synthesis new epoxy coatings to protect the structural steel in sea environment, in this paper, two epoxy-based nanocomposite samples containing low-loading of ZnO-ZrO2/ZrO2-Al2O3 nanoparticles and organobentonite nanoparticles were prepared. Pure epoxy sample and epoxy-based composite added organobentonite nanoparticles were also prepared for comparison. Dispersion of metal oxide particles and organobentonite nanoparticles into epoxy-composites were evaluated by using XRD analyses. Microhardness, adhesion and corrosion resistance over 91 days of immersion in artificial seawater (ASW) solution of new composites were studied by Vickers’ hardness test (HV test), cross-cut test, electrochemical impedance spectroscopy (EIS) and polarization curves, respectively. Results showed that combined use of low-loading fillers had a positive effect on the organobentonite exfoliation behavior in resulting epoxy-based nanocomposites. Hardness, adhesion of two novel composites increas...
Lecture Notes in Computer Science, 2014
The quorumcast routing problem is a generalization of multicasting which arises in many distribut... more The quorumcast routing problem is a generalization of multicasting which arises in many distributed applications. It consists of finding a minimum cost tree that spans the source node and at least q out of m specified nodes on a given undirected weighted graph. In this paper, we solve this problem as a mixed integer program. The experimental results show that our four approaches outperform the state of the art. A sensitivity analysis is also performed on values of q and m.
Proceedings of the Second Symposium on Information and Communication Technology - SoICT '11, 2011
Partitioning a field into parcels is one step of the project of merging and repartitioning agricu... more Partitioning a field into parcels is one step of the project of merging and repartitioning agricultural lands which emerges in many provinces in Vietnam. Historically, this problem has been conducted based on human experiences and without using optimization technology nor computer science. In this paper, we propose a model for the problem of fields partitioning taking into account real issues.
Journal of Nanoscience and Nanotechnology, 2012
In this study, the electrochemical performance of an electroless nickel/immersion gold (ENIG) sur... more In this study, the electrochemical performance of an electroless nickel/immersion gold (ENIG) surface finish was evaluated as a function of the Au immersion time by the water immersion migration test. As the Au plating time increased, the electroless nickel phosphorous (EN-P) changed from amorphous to crystalline and then increased in crystallinity. X-ray diffraction (XRD) was used to evaluate the crystallinity of the plating layer. The electrical resistance of the electrodes was tracked as the sample was immersed in water with a 5 V bias. The microstructures of the electrodes after the electrochemical migration test were observed by using secondary electron microscopy (SEM) and energy dispersive spectroscopy (EDS). As the Au immersion time increased, the EN-P's crystallinity and Au thickness increased. This enhanced the electrochemical migration protection of the surface finish layer.
Current Applied Physics, 2012
A hybrid silver (Ag)-multiwalled carbon nanotube (MWNT) nanopaste was screen-printed onto a therm... more A hybrid silver (Ag)-multiwalled carbon nanotube (MWNT) nanopaste was screen-printed onto a thermoplastic polyurethane (TPU) substrate to create a stretchable electronic interconnection. The effects of various ratios of MWNT contents on the direct current electrical resistivity and the stretchability were investigated by a four-point probe method and a single tensile test, respectively. Square and dog-bone patterns were fabricated by using a 400-mesh stencil mask on a TPU substrate. All samples were predried and then sintered at 140 C for 1 h in air. The experimental results showed the electrical resistivity of the hybrid Ag-MWNT nanopaste increased with increasing MWNT volume fraction. On the other hand, the hybrid Ag-MWNT nanopaste containing a higher composite ratio of MWNT showed larger tensile resistance. Through optical microscope (OM) observation, we found there were Ag nanoparticles on the MWNT networks under a tensile load of 5%. Prior to rupture-failure, the maximum displacement rate was measured to evaluate the stretchability. The hybrid Ag-MWNT pattern containing 1.2 wt% of MWNT showed the largest displacement rate, 3.4%, this is a 2.70 times increase compared to the Ag nanopaste without MWNTs. To improve both the electrical and mechanical properties of the hybrid Ag-MWNT nanopaste, further research is required.
Clinical Neurophysiology, 2010
Methods: Four individuals of a German family harbouring the S85C mutation in the MATR3 gene were ... more Methods: Four individuals of a German family harbouring the S85C mutation in the MATR3 gene were studied. Results: Three individuals were symptomatic. Age of onset ranged from 25 to 45 years. Creatine kinase ranged from normal to 5-fold elevation. In two patients myalgias were the initial symptom. Two patients had distal and proximal weakness of the lower limbs with Gowers manoeuvre. One patient had mild proximal weakness of the legs and generalized myalgia. Two patients showed severe fatty degeneration on MRI of the following muscles: anterior tibial, peroneus longus and brevis, gastrocnemius, soleus, semimembranosus, semitendinosus, paraspinal and deltoid. Involvement of the posterior compartment of the thigh and of the paraspinal muscles was not reported so far. One patient and the asymptomatic individual showed degeneration of the medial part of the gastrocnemius muscle on MRI. None of the patients had vocal cord palsy. Diabetes mellitus type II cosegregated with the myopathy. In none patient heart involvement was found by MRI, ultrasound, and Holter-ECG. Muscle biopsy revealed dystrophic changes with abnormal invaginations of the nucleus, perinuclear absence of sarcomers, and vacuoles. In two patients the EMG revealed myotonic discharges. Conclusion: We report on the third family worldwide with Matrin3 myopathy. The S85C missense mutation in the MATR3 gene might not only be associated with a predominantly distal myopathy but also with axial and proximal weakness. Vocal cord palsy is not obligatory. Myalgias and degeneration of the medial gastrocnemius muscle can be the first sign. Paraspinal and posterior thigh muscles are significantly affected on MRI. Due to myotonia in EMG and the distal weakness, Matrin3 myopathy contributes to the differential diagnosis of myotonic diseases.
Modern Earth Buildings, 2012
ABSTRACT Durability of earthen structures is mainly dependent on the action of water on the walls... more ABSTRACT Durability of earthen structures is mainly dependent on the action of water on the walls. In this chapter, the relevance of the current tests measuring the resistance of earthen material to water is analysed and some pertinent tests are suggested to corresponding domains of application. The second part of the chapter deals with the use of plaster to increase durability. The validation of the plaster is proposed thanks to two in situ tests: the shrinkage test and the shear test for surface coatings. The long-term performance of earthen material is then analysed through research that has been conducted on walls exposed to natural climatic conditions for several years. Key words: durability, weathering, erosion, surface coatings
Advanced Materials Research, 2014
For purpose of synthesis new epoxy coatings to protect the structural steel in sea environment, i... more For purpose of synthesis new epoxy coatings to protect the structural steel in sea environment, in this paper, two epoxy-based nanocomposite samples containing low-loading of ZnO-ZrO2/ZrO2-Al2O3 nanoparticles and organobentonite nanoparticles were prepared. Pure epoxy sample and epoxy-based composite added organobentonite nanoparticles were also prepared for comparison. Dispersion of metal oxide particles and organobentonite nanoparticles into epoxy-composites were evaluated by using XRD analyses. Microhardness, adhesion and corrosion resistance over 91 days of immersion in artificial seawater (ASW) solution of new composites were studied by Vickers’ hardness test (HV test), cross-cut test, electrochemical impedance spectroscopy (EIS) and polarization curves, respectively. Results showed that combined use of low-loading fillers had a positive effect on the organobentonite exfoliation behavior in resulting epoxy-based nanocomposites. Hardness, adhesion of two novel composites increas...
Lecture Notes in Computer Science, 2014
The quorumcast routing problem is a generalization of multicasting which arises in many distribut... more The quorumcast routing problem is a generalization of multicasting which arises in many distributed applications. It consists of finding a minimum cost tree that spans the source node and at least q out of m specified nodes on a given undirected weighted graph. In this paper, we solve this problem as a mixed integer program. The experimental results show that our four approaches outperform the state of the art. A sensitivity analysis is also performed on values of q and m.
Proceedings of the Second Symposium on Information and Communication Technology - SoICT '11, 2011
Partitioning a field into parcels is one step of the project of merging and repartitioning agricu... more Partitioning a field into parcels is one step of the project of merging and repartitioning agricultural lands which emerges in many provinces in Vietnam. Historically, this problem has been conducted based on human experiences and without using optimization technology nor computer science. In this paper, we propose a model for the problem of fields partitioning taking into account real issues.
Journal of Nanoscience and Nanotechnology, 2012
In this study, the electrochemical performance of an electroless nickel/immersion gold (ENIG) sur... more In this study, the electrochemical performance of an electroless nickel/immersion gold (ENIG) surface finish was evaluated as a function of the Au immersion time by the water immersion migration test. As the Au plating time increased, the electroless nickel phosphorous (EN-P) changed from amorphous to crystalline and then increased in crystallinity. X-ray diffraction (XRD) was used to evaluate the crystallinity of the plating layer. The electrical resistance of the electrodes was tracked as the sample was immersed in water with a 5 V bias. The microstructures of the electrodes after the electrochemical migration test were observed by using secondary electron microscopy (SEM) and energy dispersive spectroscopy (EDS). As the Au immersion time increased, the EN-P's crystallinity and Au thickness increased. This enhanced the electrochemical migration protection of the surface finish layer.
Current Applied Physics, 2012
A hybrid silver (Ag)-multiwalled carbon nanotube (MWNT) nanopaste was screen-printed onto a therm... more A hybrid silver (Ag)-multiwalled carbon nanotube (MWNT) nanopaste was screen-printed onto a thermoplastic polyurethane (TPU) substrate to create a stretchable electronic interconnection. The effects of various ratios of MWNT contents on the direct current electrical resistivity and the stretchability were investigated by a four-point probe method and a single tensile test, respectively. Square and dog-bone patterns were fabricated by using a 400-mesh stencil mask on a TPU substrate. All samples were predried and then sintered at 140 C for 1 h in air. The experimental results showed the electrical resistivity of the hybrid Ag-MWNT nanopaste increased with increasing MWNT volume fraction. On the other hand, the hybrid Ag-MWNT nanopaste containing a higher composite ratio of MWNT showed larger tensile resistance. Through optical microscope (OM) observation, we found there were Ag nanoparticles on the MWNT networks under a tensile load of 5%. Prior to rupture-failure, the maximum displacement rate was measured to evaluate the stretchability. The hybrid Ag-MWNT pattern containing 1.2 wt% of MWNT showed the largest displacement rate, 3.4%, this is a 2.70 times increase compared to the Ag nanopaste without MWNTs. To improve both the electrical and mechanical properties of the hybrid Ag-MWNT nanopaste, further research is required.
Clinical Neurophysiology, 2010
Methods: Four individuals of a German family harbouring the S85C mutation in the MATR3 gene were ... more Methods: Four individuals of a German family harbouring the S85C mutation in the MATR3 gene were studied. Results: Three individuals were symptomatic. Age of onset ranged from 25 to 45 years. Creatine kinase ranged from normal to 5-fold elevation. In two patients myalgias were the initial symptom. Two patients had distal and proximal weakness of the lower limbs with Gowers manoeuvre. One patient had mild proximal weakness of the legs and generalized myalgia. Two patients showed severe fatty degeneration on MRI of the following muscles: anterior tibial, peroneus longus and brevis, gastrocnemius, soleus, semimembranosus, semitendinosus, paraspinal and deltoid. Involvement of the posterior compartment of the thigh and of the paraspinal muscles was not reported so far. One patient and the asymptomatic individual showed degeneration of the medial part of the gastrocnemius muscle on MRI. None of the patients had vocal cord palsy. Diabetes mellitus type II cosegregated with the myopathy. In none patient heart involvement was found by MRI, ultrasound, and Holter-ECG. Muscle biopsy revealed dystrophic changes with abnormal invaginations of the nucleus, perinuclear absence of sarcomers, and vacuoles. In two patients the EMG revealed myotonic discharges. Conclusion: We report on the third family worldwide with Matrin3 myopathy. The S85C missense mutation in the MATR3 gene might not only be associated with a predominantly distal myopathy but also with axial and proximal weakness. Vocal cord palsy is not obligatory. Myalgias and degeneration of the medial gastrocnemius muscle can be the first sign. Paraspinal and posterior thigh muscles are significantly affected on MRI. Due to myotonia in EMG and the distal weakness, Matrin3 myopathy contributes to the differential diagnosis of myotonic diseases.