Deep foundations are currently used in engineering practice to solve problems caused by weak geotechnical characteristics of the ground.Impact pile driving is an interesting and viable solution from economic and techn...Deep foundations are currently used in engineering practice to solve problems caused by weak geotechnical characteristics of the ground.Impact pile driving is an interesting and viable solution from economic and technical points of view.However,it is necessary to ensure that the environmental drawbacks,namely ground-borne vibration,are adequately met.For this purpose,the authors propose an axisymmetric finite element method-perfectly matched layer(FEM-PML)approach,where the nonlinear behavior of the soil is addressed through an equivalent linear methodology.Given the complexity of the problem,an experimental test site was developed and fully characterized.The experimental work comprised in-situ and laboratory soil characterization,as well as the measurement of vibrations induced during pile driving.The comparison between experimental and numerical results demonstrated a very good agreement,from which it can be concluded that the proposed numerical approach is suitable for the prediction of vibrations induced by impact pile driving.The experimental database is available as supplemental data and may be used by other researchers in the validation of their prediction models.展开更多
This paper tries to characterize volcanic rocks through the development and application of an empirical geomechanical system. Geotechnical information was collected from the samples from several Atlantic Ocean islands...This paper tries to characterize volcanic rocks through the development and application of an empirical geomechanical system. Geotechnical information was collected from the samples from several Atlantic Ocean islands including Madeira, Azores and Canarias archipelagos. An empirical rock classification system termed as the volcanic rock system(VRS) is developed and presented in detail. Results using the VRS are compared with those obtained using the traditional rock mass rating(RMR) system. Data mining(DM) techniques are applied to a database of volcanic rock geomechanical information from the islands.Different algorithms were developed and consequently approaches were followed for predicting rock mass classes using the VRS and RMR classification systems. Finally, some conclusions are drawn with emphasis on the fact that a better performance was achieved using attributes from VRS.展开更多
The iUPQC is a Unified Power Quality Conditioner in which the series converter emulates a sinusoidal current source and the shunt converter emulates a sinusoidal voltage source. This approach provides indirect power q...The iUPQC is a Unified Power Quality Conditioner in which the series converter emulates a sinusoidal current source and the shunt converter emulates a sinusoidal voltage source. This approach provides indirect power quality compensation of the load voltage and the source current. Recent studies have suggested that the iUPQC has technical advantages in comparison with the conventional UPQC due to its reduced switching frequency characteristic. In this paper, these technical advantages are investigated. Thus, the iUPQC performance is verified through a 150 kVA industrial equipment and technical design specifications are discussed: the iUPQC power circuit design, the converters arrangement and the driver configuration. Experimental results are provided to validate the technical feasibility and power quality compensation performance.展开更多
Many Brazilian federal universities do not make use of a concrete and effective maintenance policy of its public buildings.Taking this fact into consideration,the objective of this work is to contribute with an assess...Many Brazilian federal universities do not make use of a concrete and effective maintenance policy of its public buildings.Taking this fact into consideration,the objective of this work is to contribute with an assessment of the current maintenance management carried out in three federal universities in the State of Minas Gerais:the UFOP(Federal University of Ouro Preto),UNIFEI(University of Itajubá)and the UFMG(Federal University of Minas Gerais).These universities were chosen because they have buildings with metal structures and also for being a reference in the state of Minas Gerais,which is the largest steel producer in Brazil.Knowledge was sought about the management of the campus infrastructure maintenance by raising questions about the main tools used by managers and other professionals in the field.The adopted methodology was qualitative and performed through semi-structured interviews conducted via email,with servers working directly or indirectly within each building maintenance system.The results show lacking a well-formulated plan and building maintenance programs as well as a specialized and qualified skilled labor force for the performance of services.展开更多
Scalp cooling is a widely used method to prevent chemotherapy-induced transient alopecia. Although the success rates in maintaining hair can be high, authors have expressed their concerns regarding the risk of scalp m...Scalp cooling is a widely used method to prevent chemotherapy-induced transient alopecia. Although the success rates in maintaining hair can be high, authors have expressed their concerns regarding the risk of scalp metastasis after scalp cooling. We report a case of breast cancer scalp metastasis in a patient submitted to scalp cooling for alopecia prevention and discuss the physiopathology, risks and benefits of this treatment for patients under this treatment.展开更多
Oxidized (GO) and expanded (G-Exp) graphite were employed to prepare composites with ultrahigh molecular weight polyethylene (UHMWPE) matrix using masterbatches of polyethylene with different compositions. The materia...Oxidized (GO) and expanded (G-Exp) graphite were employed to prepare composites with ultrahigh molecular weight polyethylene (UHMWPE) matrix using masterbatches of polyethylene with different compositions. The materials and a blend of UHMWPE/HDPE were prepared by extrusion and their properties were evaluated. The effect of carbon fillers on the crystalline structure, thermo dynamic-mechanical (DMTA) and thermal properties (melting and crystallization temperatures) of the composites were discussed. The thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) measurements showed that the addition of masterbatch with GO and G-Exp significantly increased the crystallite size of composites, increasing the temperatures of melting, degradation, glass transition and the degree of crystallinity of polyethylene. DMTA analysis indicated the storage and loss moduli of composites in relation to neat UHMWPE, the blend and UHMWPE/composites. SEM micrographs showed a flatter, continuous and uniform surface meaning a compact lamellar structure. The present work resulted in interesting findings on the effects of GO on the crystalline structures, mechanical and thermal properties of UHMWPE, which can lead to generalizations useful for future work.展开更多
The coarsening behavior of four quench-aged Fe-Ni-AI alloys with different Ni and Al con tents is studied.The alloys were solubilized at 1100℃for 24 h,water-quenched and aged at 850℃for periods ranging from 1 to 100...The coarsening behavior of four quench-aged Fe-Ni-AI alloys with different Ni and Al con tents is studied.The alloys were solubilized at 1100℃for 24 h,water-quenched and aged at 850℃for periods ranging from 1 to 100 h to promote phase separation and coarsening.The two alloys with the highest combined Ni and Al contents(>35 at.%)showed signs of spinodal decomposition,while the alloys with lower Ni and Al contents followed a classical nucleation process.Higher Ni and Al contents promoted an increase in NiAl(β′)phase fraction in concordance with phase equilibrium diagrams.The alloy with the highest[3'fraction presented a completely interconnected structure.The coarsening ofβ′particles in the other three alloys followed the predictions of the Lifshitz-Slyozov-Wagner(LSW)theory.The general trend was an increase in the coarsening kinetics with higher Ni and Al contents.The highest hardness was found in the alloys with higher fraction albeit these compositions are less resistant to coarsening and have been reported to present a low room-temperature ductility.展开更多
In this article, we study isoperimetric problems of the calculus of variations with left and right Riemann-Liouville fractional derivatives. Both situations when the lower bound of the variational integrals coincide a...In this article, we study isoperimetric problems of the calculus of variations with left and right Riemann-Liouville fractional derivatives. Both situations when the lower bound of the variational integrals coincide and do not coincide with the lower bound of the fractional derivatives are considered.展开更多
We present new U–Pb zircon and monazite ages from the Sunsas belt granitic magmatism in Bolivia, SW Amazonian Craton. The geochronological results revealed four major magmatic events recorded along the Sunsas belt do...We present new U–Pb zircon and monazite ages from the Sunsas belt granitic magmatism in Bolivia, SW Amazonian Craton. The geochronological results revealed four major magmatic events recorded along the Sunsas belt domains. The older igneous event formed a granitic basement coeval to the Rio Apa Terrane(1.95–1.85 Ga) in the southern domain. The second magmatic episode is represented by 1.68 Ga granites associated to the Paraguá Terrane(1.69–1.66 Ga) in the northern domain. The 1.37–1.34 Ga granites related to San Ignacio orogeny represent the third and more pervasive magmatic event, recorded throughout the Sunsas belt. Moreover, magmatic ages of ~1.42 Ga revealed that the granitogenesis associated to the Santa Helena orogeny also affected the Sunsas belt, indicating that it was not restricted to the Jauru Terrane. Lastly, the 1.10–1.04 Ga youngest magmatism was developed during the Sunsas orogeny and represents the final magmatic evolution related to Rodinia assembly. Likewise, the 1.95–1.85 and 1.68 Ga inherited zircon cores obtained in the ~1.3 Ga and 1.0 Ga granite samples suggest strong partial melting of the Paleoproterozoic sources. The 1079 ± 14 Ma and 1018 ± 6 Ma monazite crystallization ages can be correlated to the collisional tectono-thermal event of the Sunsas orogeny, associated to reactions of medium-to high-grade metamorphism. Thus, the Sunsas belt was built by heterogeneous 1.95–1.85 Ga and 1.68 Ga crustal fragments that were reworked at 1.37–1.34 Ga and 1.10–1.04 Ga related to orogenic collages. Furthermore, the 1.01 Ga monazite age suggests that granites previously dated by zircon can bear evidence of a younger thermal history. Therefore, the geochronological evolution of the Sunsas belt may have been more complex than previously thought.展开更多
The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional...The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional strate-gies for cultivating naturally occurring microorganisms often limit the discovery of novel antimicrobial producers.This study presents a protocol for targeted selection of bacterial strains using the supernatant of Paenibacillus el-gii,which produces abundant signal molecules and antimicrobial peptides.Soil samples were inoculated in these enriched culture media to selectively cultivate bacteria resistant to the supernatant,indicating their potential to produce similar compounds.The bacterial strains isolated through this method were assessed for their antibac-terial activity.In addition,the functional annotation of the genome of one of these strains revealed several gene clusters of biotechnological interest.This study highlights the effectiveness of using this approach for selective cultivation of microorganisms with potential for biotechnological applications.展开更多
The purpose of this work is to present a methodology to provide a solution to a Bi-objective Green Vehicle Routing Problem (BGVRP). The methodology, illustrated using a case study (newspaper distribution problem) and ...The purpose of this work is to present a methodology to provide a solution to a Bi-objective Green Vehicle Routing Problem (BGVRP). The methodology, illustrated using a case study (newspaper distribution problem) and literature Instances, was divided into three stages: Stage 1, data treatment;Stage 2, “metaheuristic approaches” (hybrid or non-hybrid), used comparatively, more specifically: NSGA-II (Non-dominated Sorting Genetic Algorithm II), MOPSO (Multi-Objective Particle Swarm Optimization), which were compared with the new approaches proposed by the authors, CWNSGA-II (Clarke and Wright’s Savings with the Non-dominated Sorting Genetic Algorithm II) and CWTSNSGA-II (Clarke and Wright’s Savings, Tabu Search and Non-dominated Sorting Genetic Algorithm II);Stage 3, analysis of the results, with a comparison of the algorithms. An optimization of 19.9% was achieved for Objective Function 1 (OF<sub>1</sub>;minimization of CO<sub>2</sub> emissions) and consequently the same percentage for the minimization of total distance, and 87.5% for Objective Function 2 (OF<sub>2</sub>;minimization of the difference in demand). Metaheuristic approaches hybrid achieved superior results for case study and instances. In this way, the procedure presented here can bring benefits to society as it considers environmental issues and also balancing work between the routes, ensuring savings and satisfaction for the users.展开更多
基金Programmatic funding-UIDP/04708/2020 of the CONSTRUCT-Instituto de I&D em Estruturas e Construções-funded by national funds through the FCT/MCTES(PIDDAC)Project PTDC/ECI-CON/29634/2017-POCI-01-0145-FEDER-029634-funded by FEDER funds through COMPETE2020-Programa Operacional Competitividade e Internacionalização(POCI)+1 种基金by national funds(PIDDAC)through FCT/MCTES.Grant No.2022.00898CEECIND(Scientific Employment Stimulus-5th Edition)provided by “FCT-Fundação para a Ciência e Tecnologia”。
文摘Deep foundations are currently used in engineering practice to solve problems caused by weak geotechnical characteristics of the ground.Impact pile driving is an interesting and viable solution from economic and technical points of view.However,it is necessary to ensure that the environmental drawbacks,namely ground-borne vibration,are adequately met.For this purpose,the authors propose an axisymmetric finite element method-perfectly matched layer(FEM-PML)approach,where the nonlinear behavior of the soil is addressed through an equivalent linear methodology.Given the complexity of the problem,an experimental test site was developed and fully characterized.The experimental work comprised in-situ and laboratory soil characterization,as well as the measurement of vibrations induced during pile driving.The comparison between experimental and numerical results demonstrated a very good agreement,from which it can be concluded that the proposed numerical approach is suitable for the prediction of vibrations induced by impact pile driving.The experimental database is available as supplemental data and may be used by other researchers in the validation of their prediction models.
文摘This paper tries to characterize volcanic rocks through the development and application of an empirical geomechanical system. Geotechnical information was collected from the samples from several Atlantic Ocean islands including Madeira, Azores and Canarias archipelagos. An empirical rock classification system termed as the volcanic rock system(VRS) is developed and presented in detail. Results using the VRS are compared with those obtained using the traditional rock mass rating(RMR) system. Data mining(DM) techniques are applied to a database of volcanic rock geomechanical information from the islands.Different algorithms were developed and consequently approaches were followed for predicting rock mass classes using the VRS and RMR classification systems. Finally, some conclusions are drawn with emphasis on the fact that a better performance was achieved using attributes from VRS.
文摘The iUPQC is a Unified Power Quality Conditioner in which the series converter emulates a sinusoidal current source and the shunt converter emulates a sinusoidal voltage source. This approach provides indirect power quality compensation of the load voltage and the source current. Recent studies have suggested that the iUPQC has technical advantages in comparison with the conventional UPQC due to its reduced switching frequency characteristic. In this paper, these technical advantages are investigated. Thus, the iUPQC performance is verified through a 150 kVA industrial equipment and technical design specifications are discussed: the iUPQC power circuit design, the converters arrangement and the driver configuration. Experimental results are provided to validate the technical feasibility and power quality compensation performance.
文摘Many Brazilian federal universities do not make use of a concrete and effective maintenance policy of its public buildings.Taking this fact into consideration,the objective of this work is to contribute with an assessment of the current maintenance management carried out in three federal universities in the State of Minas Gerais:the UFOP(Federal University of Ouro Preto),UNIFEI(University of Itajubá)and the UFMG(Federal University of Minas Gerais).These universities were chosen because they have buildings with metal structures and also for being a reference in the state of Minas Gerais,which is the largest steel producer in Brazil.Knowledge was sought about the management of the campus infrastructure maintenance by raising questions about the main tools used by managers and other professionals in the field.The adopted methodology was qualitative and performed through semi-structured interviews conducted via email,with servers working directly or indirectly within each building maintenance system.The results show lacking a well-formulated plan and building maintenance programs as well as a specialized and qualified skilled labor force for the performance of services.
文摘Scalp cooling is a widely used method to prevent chemotherapy-induced transient alopecia. Although the success rates in maintaining hair can be high, authors have expressed their concerns regarding the risk of scalp metastasis after scalp cooling. We report a case of breast cancer scalp metastasis in a patient submitted to scalp cooling for alopecia prevention and discuss the physiopathology, risks and benefits of this treatment for patients under this treatment.
文摘Oxidized (GO) and expanded (G-Exp) graphite were employed to prepare composites with ultrahigh molecular weight polyethylene (UHMWPE) matrix using masterbatches of polyethylene with different compositions. The materials and a blend of UHMWPE/HDPE were prepared by extrusion and their properties were evaluated. The effect of carbon fillers on the crystalline structure, thermo dynamic-mechanical (DMTA) and thermal properties (melting and crystallization temperatures) of the composites were discussed. The thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) measurements showed that the addition of masterbatch with GO and G-Exp significantly increased the crystallite size of composites, increasing the temperatures of melting, degradation, glass transition and the degree of crystallinity of polyethylene. DMTA analysis indicated the storage and loss moduli of composites in relation to neat UHMWPE, the blend and UHMWPE/composites. SEM micrographs showed a flatter, continuous and uniform surface meaning a compact lamellar structure. The present work resulted in interesting findings on the effects of GO on the crystalline structures, mechanical and thermal properties of UHMWPE, which can lead to generalizations useful for future work.
基金The authors would like to thank Consejo Nacional de Ciencia y Tecnologfa(CONACYT)(Project CB-2013 No.222459)IPN-SIP-BEIFI for their financial support.
文摘The coarsening behavior of four quench-aged Fe-Ni-AI alloys with different Ni and Al con tents is studied.The alloys were solubilized at 1100℃for 24 h,water-quenched and aged at 850℃for periods ranging from 1 to 100 h to promote phase separation and coarsening.The two alloys with the highest combined Ni and Al contents(>35 at.%)showed signs of spinodal decomposition,while the alloys with lower Ni and Al contents followed a classical nucleation process.Higher Ni and Al contents promoted an increase in NiAl(β′)phase fraction in concordance with phase equilibrium diagrams.The alloy with the highest[3'fraction presented a completely interconnected structure.The coarsening ofβ′particles in the other three alloys followed the predictions of the Lifshitz-Slyozov-Wagner(LSW)theory.The general trend was an increase in the coarsening kinetics with higher Ni and Al contents.The highest hardness was found in the alloys with higher fraction albeit these compositions are less resistant to coarsening and have been reported to present a low room-temperature ductility.
基金supported by FEDER funds through COMPETE - Operational Programme Factors of Competitiveness("Programa Operacional Factores de Competitividade")Portuguese funds through the Center for Research and Development in Mathematics and Applications(University of Aveiro) and the Portuguese Foundation for Science and Technology("FCT - Fundao para a Ciencia e a Tecnologia"),within project PEst-C/MAT/UI4106/2011 with COMPETE number FCOMP-01-0124-FEDER-022690
文摘In this article, we study isoperimetric problems of the calculus of variations with left and right Riemann-Liouville fractional derivatives. Both situations when the lower bound of the variational integrals coincide and do not coincide with the lower bound of the fractional derivatives are considered.
基金The authors acknowledge the support of the Laboratório de Geocronologia(Universidade de Brasília)the Grupo de Pesquisa em Evolução Crustal e Tectônica(Guaporé)+3 种基金This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil(CAPES)-Finance Code 001The authors also acknowledge Fundação de ApoioàPesquisa do Distrito Federal(FAPDF)INCT Estudos Tectônicos(CNPq-CAPESFAPDF)for financial support.IMN thanks CAPES and Programa de Excelência Acadêmica(PROEX,Edital-0487)for granting the Doctorate scholarshipRAF and ASR acknowledge CNPq for research fellowship.
文摘We present new U–Pb zircon and monazite ages from the Sunsas belt granitic magmatism in Bolivia, SW Amazonian Craton. The geochronological results revealed four major magmatic events recorded along the Sunsas belt domains. The older igneous event formed a granitic basement coeval to the Rio Apa Terrane(1.95–1.85 Ga) in the southern domain. The second magmatic episode is represented by 1.68 Ga granites associated to the Paraguá Terrane(1.69–1.66 Ga) in the northern domain. The 1.37–1.34 Ga granites related to San Ignacio orogeny represent the third and more pervasive magmatic event, recorded throughout the Sunsas belt. Moreover, magmatic ages of ~1.42 Ga revealed that the granitogenesis associated to the Santa Helena orogeny also affected the Sunsas belt, indicating that it was not restricted to the Jauru Terrane. Lastly, the 1.10–1.04 Ga youngest magmatism was developed during the Sunsas orogeny and represents the final magmatic evolution related to Rodinia assembly. Likewise, the 1.95–1.85 and 1.68 Ga inherited zircon cores obtained in the ~1.3 Ga and 1.0 Ga granite samples suggest strong partial melting of the Paleoproterozoic sources. The 1079 ± 14 Ma and 1018 ± 6 Ma monazite crystallization ages can be correlated to the collisional tectono-thermal event of the Sunsas orogeny, associated to reactions of medium-to high-grade metamorphism. Thus, the Sunsas belt was built by heterogeneous 1.95–1.85 Ga and 1.68 Ga crustal fragments that were reworked at 1.37–1.34 Ga and 1.10–1.04 Ga related to orogenic collages. Furthermore, the 1.01 Ga monazite age suggests that granites previously dated by zircon can bear evidence of a younger thermal history. Therefore, the geochronological evolution of the Sunsas belt may have been more complex than previously thought.
文摘The biotechnological industry faces a crucial demand for novel bioactive compounds,particularly antimicrobial agents,to address the rising challenge of bacterial resistance to current available antibiotics.Traditional strate-gies for cultivating naturally occurring microorganisms often limit the discovery of novel antimicrobial producers.This study presents a protocol for targeted selection of bacterial strains using the supernatant of Paenibacillus el-gii,which produces abundant signal molecules and antimicrobial peptides.Soil samples were inoculated in these enriched culture media to selectively cultivate bacteria resistant to the supernatant,indicating their potential to produce similar compounds.The bacterial strains isolated through this method were assessed for their antibac-terial activity.In addition,the functional annotation of the genome of one of these strains revealed several gene clusters of biotechnological interest.This study highlights the effectiveness of using this approach for selective cultivation of microorganisms with potential for biotechnological applications.
文摘The purpose of this work is to present a methodology to provide a solution to a Bi-objective Green Vehicle Routing Problem (BGVRP). The methodology, illustrated using a case study (newspaper distribution problem) and literature Instances, was divided into three stages: Stage 1, data treatment;Stage 2, “metaheuristic approaches” (hybrid or non-hybrid), used comparatively, more specifically: NSGA-II (Non-dominated Sorting Genetic Algorithm II), MOPSO (Multi-Objective Particle Swarm Optimization), which were compared with the new approaches proposed by the authors, CWNSGA-II (Clarke and Wright’s Savings with the Non-dominated Sorting Genetic Algorithm II) and CWTSNSGA-II (Clarke and Wright’s Savings, Tabu Search and Non-dominated Sorting Genetic Algorithm II);Stage 3, analysis of the results, with a comparison of the algorithms. An optimization of 19.9% was achieved for Objective Function 1 (OF<sub>1</sub>;minimization of CO<sub>2</sub> emissions) and consequently the same percentage for the minimization of total distance, and 87.5% for Objective Function 2 (OF<sub>2</sub>;minimization of the difference in demand). Metaheuristic approaches hybrid achieved superior results for case study and instances. In this way, the procedure presented here can bring benefits to society as it considers environmental issues and also balancing work between the routes, ensuring savings and satisfaction for the users.
