Search

This paper presents a numerical study on moisture transport in brick masonry walls with a special focus on the simulation of their hygric performance as well as the hydraulic phenomena at the brick-mortar interface. A diffusivity model based on Fick's law is used to describe the moisture transport accounting for both liquid and water vapor movement. The necessary hygric parameters are obtained directly from experimental tests or determined by curve fitting. The proposed model is validated with respect to water absorption and drying tests. The good-fitness of the results is qualitatively assessed and an overall good agreement is found between the simulated and measured curves. It is demonstrated that the chosen liquid water diffusivity expression needs to be adjusted to represent drying processes; the necessary adjustment is made through a diffusivity factor implemented in the original analytical expression. The interface impact on water absorption is introduced as a hydraulic resistance. Moreover, it is hypothesized that the presence of successive interfaces entails an additive in-series effect. Conversely, the interfacial impact on drying is negligible. Finally, the proposed model is extended to different modeling approaches commonly used for mechanical studies of masonry. The necessary input data, modeling methodology, advantages and disadvantages associated with each modeling strategy are also discussed. The present study points out the need of studying water absorption in multi-layered structures made up of constituents with relatively similar hygric behavior. In such cases, the impact of imperfect contact at the interface between materials is not negligible., Article publishing charge (APC) funded by agreement between Portugal (FCT/FCCN) and Elsevier

In the 1970s, social inclusion became a ubiquitous issue in the global scenario and professionals in the field of People Management began to adopt strategies for the inclusion of people with disabilities (PWD) in the labor market. However, currently, many organizations still face difficulties in hiring PWD, not adopting an effective inclusion, despite being provided for in Law number 8,213 of July 24, 1991 (Law of Quotas for PWD). Given this fact, the objective of this research was to analyze how Law number 8,213 is being applied in a mattress factory located in the city of Três Rios/RJ. This is a research of qualitative approach, which was conducted through an in-depth interview with the manager of the People Management area, through a questionnaire based on the Model of Campos, Vasconcellos and Kruglianskas (2013). To carry out the data analysis, it was used the content analysis technique according to Bardin (1977). As a result of the research, it was found that the factory does not perform as a strategy of People Management an effective inclusion program for the PWD, since practices are not developed to facilitate accessibility, retention and awareness of such individuals in the workplace. It is concluded that the admission of PWD is made tied to the legal obligation, i.e., for the mere fulfillment of the minimum percentage required by Law number 8,213. In this sense, the adoption of palliative strategies prevails in the factory so that people with disabilities are only inserted into the workplace.

The implementation of condition monitoring for damage identification and the generation of a reliable digital twin are essential elements of preventive conservation. The application of this promising approach to Cultural Heritage (CH) sites is deemed truly beneficial, constituting a minimally invasive mitigation strategy and a cost-effective decision-making tool. In this light, the present work focuses on establishing an informative virtual model as a platform for the conservation of the monastery of Santa Maria de Salzedas, a CH building located in the north of Portugal. The platform is the first step towards the generation of the digital twin and is populated with existing documentation as well as new information collected within the scope of an inspection and diagnosis programme. At this stage, the virtual model encompasses the main cloister, whose structural condition and safety raised concerns in the past and required the implementation of urgent remedial measures. In the definition of a vibration-based condition monitoring strategy for the south wing of the cloister, five modes were identified by carrying out an extensive dynamic identification. Nonetheless, significant challenges emerged due to the low amplitude of the ambient-induced vibrations and the intrusiveness of the activities. To this end, a data-driven Optimal Sensor Placement (OSP) approach was followed, testing and comparing five heuristic methods to define a good trade-off between the number of sensors and the quality of the collected information. The results showed that these algorithms for OSP allow the selection of sensor locations with good signal strength.

In the last two decades, high-rise timber buildings have been built using the glulam truss system, even with limited openings. Moment-resisting timber frames (MRTF) with semi-rigid beam-to-column connections can be an architecture-friendly way to provide a load-carrying system to vertical and horizontal loads for timber buildings. In these structures, connections of adequate ductility are crucial to ensure robustness and energy dissipation. This paper presents a review of the main types of timber beam–column moment connections with improved ductility and proposes to carry out a ductility assessment of these connections based on the most relevant ductility factors. Joints have a significant influence on the global performance of MRTF, and the application of ductile connections have improved the mechanical parameters of the timber frame. The reinforced bolted slotted-in steel plate and glued-in rods connections have similar mechanical performance, with high rotation capacity and good ultimate moment, but exhibited different failure modes under cyclic loading. The connections were classified within ductility classes. In general, the glued-in steel rods presented better results because of the high influence of steel profiles in the connection yielding. Despite the excellent mechanical behavior, the reinforced bolted slotted-in steel plate connections presented medium ductility values.

Quality control (QC) may be applied as a framework for maintenance planning when assigning different intervention measures to single structural elements or systems. This work proposes a reliability-based maintenance decision-making process for planning visual inspections on bridges based on the value of information and prior inspection data, and also promotes updating and improvement cycles for subsequent planning. To that aim, an integration between SHM (Structural Health Monitoring) data with a multidisciplinary approach is proposed to obtain a reliability index attending to QC. The data analysis was mainly carried out with respect to an existing measurement database and structural assessments, which were combined to obtain weighted importance coefficients for each component according to their significance in the structure. The Iranian railway network has a built stock of nearly 28,200 bridges from which a database obtained from 104 bridges was studied in this work, considering the data obtained from technical identification checklists. The results were then calibrated and validated with a dataset of seven bridges, which were inspected onsite. The inspection comprised the identification and grading of damages and defects on each element. Observed defects were considered as input for the risk analysis of each component of the network by considering the probability of detection, occurrence and its likely consequences. Decision making with inspection and intervention costs optimization was then performed, for a specific case study, using Principal Component Analysis (PCA) together with the value of information (VOI) for data filtering. With this approach, several parameters with lower values reduced from inspection and other valuable data remain for bridge quality assessment with optimum maintenance cost.

Unreinforced masonry structures are susceptible to man-made hazards such as impact and blast loading. However, the literature on this subject mainly focuses on masonry wall behavior, and there is a knowledge gap about the behavior of masonry arches under high-strain loading. In this context, this research aims to investigate both quasistatic and impact response of a dry-joint stone masonry arch using the discrete element method. Rigid blocks with noncohesive joint models are adopted to simulate dry-joint assemblages. First, the employed modeling strategy is validated utilizing the available experimental findings, and then sensitivity analyses are performed for both static and impact loading, considering the effect of joint friction angle, contact stiffness, and damping parameters. The outcomes of this research strengthen the existing knowledge in the literature regarding the computational modeling of masonry structures that are subjected to usual and extreme loading conditions. The results highlight that applied discontinuum-based numerical models are more sensitive to stiffness parameters in high-strain loading than static analysis.

This paper presents a digital tool for the rapid structural assessment of historic masonry domes. It is especially suited for masonry domes that present long meridian cracks, ergo each partitioned element governed by a pushing failure mode. The proposed procedure considers a Heyman’s no-tension mechanical model has been implemented within a commercial user-friendly visual programming environment. The numerical approach consists of a parametric modelling of the failure mechanism and, therefore, exploring the domain of possible solutions using the theorems of the limit analysis. Hence, a heuristic search method is subsequently adopted to refine the geometry of the collapse mechanism and to compute the value of the horizontal trust. The validation of the developed approach has been achieved considering the Saint Peter’s dome. As reported in the literature, the behaviour of the Saint Peter’s dome gradually shifted from a rigid shell-type – stiffened by hoop stresses –, towards a pushing type of dome partitioned by long meridian cracks. The study also evaluated the structural integrity of the drum. In converse with more time-consuming and advanced methods of analysis, the present procedure allows the users to perform a structural assessment of a historic masonry dome in a fast and computationally efficient manner. The developed digital tool will be freely available from a web archive hosted by the University of Minho and, therefore, easily able to reach students, researchers and structural engineers.

In the context of historical heritage, curved masonry structures as arches, vaults and domes represent the most distinctive and charming feature. Since the 17th century, several approaches have been developed in order to analyze their behavior, achieving nowadays techniques enable to combine ancient and modern methods. However, as these elements act as weak points of the structures during seismic events, the necessity of evaluating their vulnerability and safety level pushed the research to implement new numerical approaches. Although, the behavior of such structures is still not deeply investigated in literature as the high number of variables and uncertainty involved. An innovative discrete homogenized model approach is here proposed. The method provides the main features needed for proper simulation of masonry curved structures, including the orthotropy and the typical in-and-out-of-plane coupled behavior exhibited by masonry vaults. Moreover, homogenization procedures directly implemented in the method allows reducing by far the number of variables, leading to non-linear analyses without unpractical computational time. The model is conceived as an assembly of elastic units joint by non-linear interfaces. These latter are modeled as bricks elements and Concrete Damage Plasticity is used for modeling non-linear mechanical properties, coming from homogenization procedures. The discrete mesh is obtained automatically by means of an ad-hoc script. With the aim to validate the proposed approach, some non-linear simulations are carried out on examples of an unreinforced dome, of which experimental and numerical data are available, showing the reliability of the method and the accuracy of reproducing the evolution of the damage with a limited computational burden.

The seismic behaviour of unreinforced masonry (URM) structures is generally governed by a complex interaction between the out-of-plane and in-plane responses of the walls, depending on the in-plane stiffness of floor/roof diaphragms and the efficiency of wall-to-floor/roof connections. The presence of timber diaphragms, which are typically characterised by low in-plane stiffness and poor connection to the masonry walls, adds challenges to the numerical modelling and analysis, as well as to the structural assessment of URM structures under seismic actions. This work aims at investigating the applicability of refined FE modelling using macro-modelling approach and mass-proportional pushover analysis for simulating the response of URM structures with flexible diaphragms, comparing the results with experimental data obtained from incremental dynamic testing. A full-scale two-storey prototype building with timber diaphragms, which was tested in shaking table at the European Centre for Training and Research in Earthquake Engineering (EUCENTRE), in Italy, was considered to perform this study. A refined finite element (FE) model was developed in DIANA software, considering the wall-to-diaphragm (WTD) connections. While the strength values of masonry were adopted according to axial and diagonal compression tests, the modulus of elasticity was calibrated after simulating in-plane cyclic shear tests of masonry piers, which were part of the same experimental program at EUCENTRE. Recommendations from international guidelines were used to derive the assumed material properties for diaphragms and wall-to-diaphragm connections. Mass-proportional pushover analysis was performed and a comparison between numerical and experimental results is presented to investigate the assumptions, advantages and limitations of the presented numerical modelling and analysis approach., This work was financed by FCT -Portuguese Foundation for Science and Technology, within the INFRARISK PhD program and ISISE (Ref. UID/ECI/04029/2019). The authors would like to acknowledge Prof. Guido Magenes and Dr. Ilaria Senaldi for providing useful information on the experimental program at EUCENTRE.

The concepts of structural assessment and retrofit of historical constructions are of particular complexity and require advanced knowledge in material science, conservation techniques and structural analysis. In particular, adobe constructions, given their low mechanical properties and brittle failure modes, are in immense need of comprehensive assessment and retrofitting plans. The current work focuses on the adobe Church of Kuñotambo in Peru, having experienced long periods of deterioration and earthquake-related damage. Under the ongoing Seismic Retrofitting Project (SRP) of the Getty Conservation Institute (GCI), the structural assessment of the church initiated in 2015 confirmed the low lateral capacity of the building and the poor connectivity between the structural parts. Based on the existing cracks and damage, a strengthening scheme was optimized and validated. After the implementation of the retrofitting plan, the quality of its execution and efficiency were assessed in 2019 with a new in situ campaign, which included ambient vibration testing (AVT) and sonic testing. From the acquired field data, the FE model of the retrofitted church was optimized, by updating the stiffness properties of masonry and discontinuities. Moreover, nonlinear static analyses were performed on the updated model in all in-plan directions. Finally, a displacement-based performance assessment was undertaken, under different earthquake limit states, demonstrating the adequacy of the retrofitting., Partial funding by Getty Conservation Institute – Seismic Retrofitting Project.

The preservation and seismic risk mitigation of built cultural heritage is considered today as a major priority in the international political agenda. Among the great variety of heritage structures spread worldwide, masonry towers belong to one of the most vulnerable categories against earthquake actions due to their morphological and material singularity. The proper understanding of the structural behavior of these artefacts at the micro, meso and macro scales, combined with a thorough knowledge of the best analysis practices deriving from the shared experience of the scientific community working in this field, is a fundamental prerequisite to appropriately address their seismic assessment. In this context, the present work offers an extensive discussion on the major challenges that slender monumental towers pose in terms of characterization of their actual behavior under seismic actions. A critical appraisal of the principal analysis methods applicable to the study of these structures is also presented along with a brief review of the existing modelling strategies for their numerical representation. Relevant examples are discussed in support of each argument. In spite of being a relatively young discipline, earthquake engineering has made remarkable progress in the last years and appropriate modi operandi have been consolidating to tackle the seismic assessment of unconventional systems, such as slender heritage structures. The work is conceived in a format of interest for both practitioners and researchers approaching the seismic assessment of this type of structures, and for those in need of an overall practical review of the topic.

Seismic actions have been a great challenge for structures in the structural engineering community, and the need for further developments has been approved by catastrophic seismic events at each time. Reproducing the dynamic behavior of structures with an acceptable level of accuracy is a complex task due to uncertainties related to the geometrical, material and physical structural system, more particularly, in the case of existing historical masonry structures. The use of dynamic analysis is a better choice than the use of static or quasi-static approaches since it is a better representation of the dynamic response of a structure by taking account of its energy dissipation capacity. The scope of the present paper is focused on a seismic assessment of a historical masonry structure, Kütahya Kurşunlu Mosque located in Turkey, before and after it has been retrofitted. The historical mosque is located in a seismic prone zone where it is crucial to ensure seismic safety of structures and the local community. Based on the condition of the structure reported from the site inspections, a seismi retrofitting by using steel girder elements was implemented on the structural load-bearing walls. The effectiveness of the seismic retrofitting to the seismic response of the mosque was investigated by means of the finite element method. Three bi-directional nonlinear dynamic analyses were performed by using real ground motion records aiming at the validation of the nonlinear dynamic response of the numerical model in terms of damage patterns, and demonstration of the contribution of the seismic retrofitting by comparing the representative model with its retrofitted counterpart. The comparison has been carried out in terms of peak displacement and damage patterns. It is found that the contribution of the seismic retrofitting is considerable for the out-of-plane displacements of the load-bearing walls. Furthermore, a good correlation between existing damage and the numerical damage is achieved, and, therefore, the validation of the nonlinear response of the representative model is attained.

This study explores the use of macro-modelling techniques based on smeared crack and damage-plastic constitutive laws for the cyclic in-plane analysis of masonry panels. The numerical investigation is focused on two material macromechanical models, known as Total Strain Cracking and Crack and Plasticity models. These show some limitations when analysing the behaviour of masonry structures subjected to in-plane cyclic loading. A modified version of the Drucker-Prager model including cohesive softening is introduced to overcome these shortcomings. A suite of numerical simulations is performed referring to an experimental campaign on two masonry (squat and slender) panels. A comparison of distinctive features of flexural and shear response of masonry panels is addressed. The results derived from the two FE macro-models are compared with the experimental outcomes, highlighting the effects of geometry, stiffness degradation, and post-peak energy dissipation. Furthermore, a comparison with another macromechanical model is performed.

The seismic response of masonry structures without box-type behaviour is given by a complex interaction between in-plane and out-of-plane behaviours. Previous earthquakes demonstrated that out-of-plane failure mechanisms represent the main cause of structural collapses of UnReinforced Masonry (URM) and historical structures. Previous experimental and analytical studies, investigating the out-of-plane behaviour of URM structures, mostly considered the effects of one-way bending moment. In this regard, recent experimental campaigns and numerical simulations have been conducted in order to investigate the out-ofplane behaviour of masonry walls subjected to two-way bending. These investigations have demonstrated the complexity of this mechanism and stressed the need for accurate numerical tools capable of providing reliable predictions in terms of ultimate strength and failure mechanisms. This paper focuses on the assessment of the dynamic behaviour of a U-shape URM prototype, subjected to shaking table tests, by means of a simplified computational strategy denoted as Discrete Macro-Element Method (DMEM). In this investigation, a comparison between experimental and numerical results was conducted in order to validate the capabilities of the proposed modelling approach. Subsequently, a parametric analysis was carried aiming at determining the influence that masonry mechanical properties, and additional model parameters, have on the out-of-plane nonlinear dynamic response of URM masonry structures.

This book is about Heritage Building Information Modelling (HBIM). This is a term that has only begun to be used in the latter part of the last decade, since Building Information Modelling (BIM) superseded 3D digital modelling and computer aided design (CAD) as the term generally used to describe the use of information and communication technology (ICT) for the design, construction, and procurement of the modern built environment. It is sometimes also defined as Historic Building Information Modelling, a somewhat narrower term (Murphy et al 2009). One of the earliest definitions of the principles and purpose of Heritage Information Modelling stemmed from the Getty Conservation Institute’s Recording, Documentation,& Information Management (RecorDIM) Initiative (2003–2007) (Eppich & Chabbi 2007). The book provides a critical analysis of current HBIM development and research. Building Information Modelling is still variously defined and described, and so it is that current approaches that are claimed to be HBIM display equal or greater diversity. This introductory chapter first discusses the origins of HBIM, then outlines the format of the book and gives a context to that format. It will be of use to all those who care for our built heritage and seek better tools with which to record its value, clarify its significance, and conserve it in the long term. In preparing for the workshop on HBIM in March 2015 in Luxor, Egypt, the authors claimed a need for “analysis of the long-term potential for sustainable redeployment and reuse of Heritage”. They argued that “increasing resource scarcities require improved analytical tools for conserving existing buildings in general, and mitigating climate change; and that Heritage buildings form a particular challenge, due to the need to conserve their historic and aesthetic worth, addressing environmental social and economic sustainability.” These pillars of sustainability are not fixed; perceptions of quality of life change over time, with resulting dissatisfaction with heritage structures and a view that they have become unfit for their purpose. The authors also claimed that the “Heritage Buildings that are most relevant and at risk were not so much unoccupied national or internationally important monuments, but the cultural backdrop of occupied architecture that: has historic and aesthetic value; demands particular maintenance and refurbishment skills and analysis; deploys expensive materials that may be in increasing shortage; and generally cannot affordably be replaced with better performing new constructions.

This paper presents the development of a three dimensional computational model, based on the Discrete Element Method (DEM), which was used to investigate the effect of the angle of skew on the load carrying capacity of twenty-eight different in geometry single span stone masonry arches. Each stone of the arch was represented as a distinct block. Mortar joints were modelled as zero thickness interfaces which can open and close depending on the magnitude and direction of the stresses applied to them. The variables investigated were the arch span, the span : rise ratio and the skew angle. At each arch, a full width vertical line load was applied incrementally to the extrados at quarter span until collapse. At each load increment, the crack development and vertical deflection profile was recorded. The results compared with similar “square” (or regular) arches. From the results analysis, it was found that an increase in the angle of skew will increase the twisting behaviour of the arch and will eventually cause failure to occur at a lower load. Also, the effect of the angle of skew on the ultimate load that the masonry arch can carry is more significant for segmental arches than circular one.

This work presents a procedure for the use of probabilistic modelling techniques in the assessment of safety parameters of existing timber structures, when influenced by two types of actions. The parameters of the models have been defined as probabilistic variables, and Monte Carlo simulation technique was taken into account for safety evaluation. The case study here examined concerns four king post trusses on which a safety evaluation method was conducted to determine a target reliability index. Since the structures presented a high level of deterioration, a model considering the variation of the residual cross-section and the influence of environment in resistance was taken into account. Time dependent deterioration models have also been considered. With the results given by the different used models, it was possible to obtain probabilities of failure and respective reliability indices, as well as time evolution deterioration curves for a deteriorated historical structure.

Part 1: Framework Vernacular architecture: A paradigm of the local seismic culture F. Ferrigni Vernacular architecture? G.D. Carlos, M.R. Correia, S. Rocha & P. Frey Seismic-resistant building practices resulting from Local Seismic Culture J. Ortega, G. Vasconcelos & M.R. Correia Practices resulting from seismic performance improvement on heritage intervention R.F. Paula & V. Coias Criteria and methodology for intervention in vernacular architecture and earthen heritage M.R. Correia Structural conservation and vernacular construction P.B. Lourenco, H. Varum, G. Vasconcelos & H. Rodrigues Seismic retrofitting of historic earthen buildings C. Cancino & D. Torrealva Local building cultures valued to better contribute to housing reconstruction programs T. Joffroy & P. Garnier Part 2: Local seismic culture around the world Local seismic culture in Latin America L.F. Guerrero Baca & J. Vargas Neumann Local seismic culture in the Mediterranean region L. Dipasquale & S. Mecca The central and eastern Asian local seismic culture: Three approaches F. Ferrigni The earthquake resistant vernacular architecture in the Himalayas Randolph Langenbach Traditional construction in high seismic zones: A losing battle? The case of the 2015 Nepal earthquake X. Romao, E. Pauperio & A. Menon Case study: Local seismic culture in vernacular architecture in Algeria A. Abdessemed, Y. Terki & D. Benouar Case study: Assessment of the seismic resilience of traditional Bhutanese buildings T. Ilharco, A.A. Costa, J.M. Guedes, B. Quelhas, V. Lopes, J.L. Vasconcelos & G.S.C. Vasconcelos Case study: Vernacular seismic culture in Chile N. Jorquera & H. Pereira Case study: Seismic resistant typologies technology in vernacular architecture in Sichuan Province, China J. Yao Case study: Seismic retrofitting in ancient Egyptian adobe architecture S. Lamei Case study: Seismic resistant constructive systems in El Salvador F. Gomes, M.R. Correia & R.D. Nunez Case study: Seismic retrofitting of Japanese traditional wooden structures N. Takiyama Case study: Seismic retrofitting constructive typology of vernacular Moroccan architecture (Fez) A. Abdessemed-Foufa Case study: Local seismic culture in Romanian vernacular architecture M. Harmanescu & E.S. Georgescu Case study: Local seismic culture in Taiwan vernacular architecture Y.R. Chen Part 3: Local seismic culture in Portugal Recognising local seismic culture in Portugal, the SEISMIC-V research M.R. Correia & G.D. Carlos Seismic hazard analysis: An overview J.F.B.D. Fonseca & S.P. Vilanova A brief paleoseismology literature review: Contribution for the local seismic culture study in Portugal M.R. Correia, M. Worth & S. Vilanova Portuguese historical seismicity G.Sousa Seismic behaviour of vernacular architecture H.Varum, H. Rodrigues, P.B. Lourenco & G. Vasconcelos The design of 1758's master plan and the construction of Lisbon 'downtown': A humanistic concept? V. Lopes dos Santos Timber frames as an earthquake resisting system in Portugal E.Poletti, G. Vasconcelos & P.B. Lourenco Part 4: Portuguese local seismic culture: Assessment by regions Lisbon: Downtown's reconstruction after the 1755 earthquake G.D. Carlos, M.R. Correia, G. Sousa, A. Lima, F. Gomes & V. Lopes dos Santos The 1909 earthquake impact in the Tagus Leziria region E. Gomes, A. Lima, G.D. Carlos & M.R. Correia Costal Alentejo region: Identification of local seismic culture F. Gomes, A. Lima, G.D. Carlos & M.R. Correia Seismic-resistant elements in the Historical Centre of Evora G.D. Carlos, M.R. Correia, G. Sousa, A. Lima & F. Gomes Seismic-resistant features in Lower Alentejo's vernacular architecture A. Lima, F. Gomes, G.D. Carlos, D. Viana & M.R. Correia Seismic vulnerability of the Algarve coastal region G.D. Carlos, M.R. Correia, G. Sousa, A. Lima, F. Gomes, L. Felix & A. Feio The high and intense seismic activity in the Azores F. Gomes, M.R. Correia, G.D. Carlos & A. Lima Part 5: Typology performance study Seismic behaviour assessment of vernacular isolated buildings J. Ortega, G. Vasconcelos, P.B. Lourenco, H. Rodrigues & H. Varum Seismic behaviour analysis and retrofitting of a row building R.S. Barros, A. Costa, H. Varum, H. Rodrigues, P.B. Lourenco & G. Vasconcelos Seismic vulnerability of vernacular buildings in urban centres-the case of Vila Real de Santo Antonio J. Ortega, G. Vasconcelos, P.B. Lourenco, H. Rodrigues & H. Varum Part 6: Conclusions of the research Systematisation of seismic mitigation planning at urban scale D.L. Viana, A. Lima, G.D. Carlos, F. Gomes, M.R. Correia, P.B. Lourenco & H. Varum Systematisation of seismic retrofitting in vernacular architecture A. Lima, M.R. Correia, F. Gomes, G.D. Carlos, D. Viana, P.B. Lourenco & H. Varum Common damages and recommendations for the seismic retrofitting of vernacular dwellings M.R. Correia, H. Varum & P.B. Lourenco

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a widely used technique for assessing tissue physiology. Spoiled gradient echo (SPGR) pulse sequences are one of the most common methods for acquisition of DCE-MRI data, providing high temporal and spatial resolution with strong T(1)-weighting. Conversion of SPGR signal to concentration is briefly reviewed, and a new closed-form expression for concentration measurement uncertainty for finite signal-to-noise ratio (SNR) and baseline scan time is derived. This result is applicable to arbitrary concentration-dependent relaxation rate and is valid over the same domain as the theoretical SPGR signal equation. Expressions for the lower and upper bounds on measurable concentration are also derived. The existence of a concentration- and tissue-dependent optimal flip angle that minimizes concentration uncertainty is demonstrated and it is shown that, for clinically relevant pulse sequence parameters, this optimal flip angle is significantly larger than the corresponding Ernst angle. Analysis of three pulse sequences from the DCE-MRI literature shows that optimization of flip angle using the methods discussed here leads to potential improvements of 10-1166% in effective SNR over the 0.5-5.0 mM concentration range with minimal or no loss of measurement accuracy down to 0.1 mM. In vivo data from three study patients provide further support for our theoretical expression for concentration measurement uncertainty, with predicted and experimental estimates agreeing to within +/- 30%. Equations for concentration bias resulting from biases in flip angle and from pre-contrast relaxation time and contrast relaxivity (both longitudinal and transverse) are also derived in closed-form. The resulting equations show the potential for significant contributions to bias in concentration measurement arising from even relatively small mis-specification of flip angle and/or pre-contrast longitudinal relaxation time, particularly at high contrast concentrations.

O estudo da avaliação de alternativas de controle da Leucose Enzoótica Bovina (LEB), foi aplicado num rebanho de 110 animais das raças holandesa e jersey, pertencente a Em presa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), Cambuquira, Minas Gerais, onde a prevalência inicial da doença era de 70,19%, com o objetivo de avaliar a eficiência de um conjunto de medidas preventivas, apropriadas a determinado sistema de produção, a fim de prevenir a transmissão horizontal do Vírus Leucose Bovina (VLB). Para verificação do estado sorológico dos bovinos, utilizou-se como diagnóstico, a prova de imunodifusão em gel de agar (IDGA), em placa, com antígeno glicoprotéico. Foram acompanhados 47 bezerros, do nascimento aos 19 meses de idade, período de execução do programa de controle, num total de oito testes sorológicos. Após o nascimento, os bezerros eram separados das mães, sendo que 13 bezerros receberam colostro e/ou leite de vacas soronegativas, e 34 bezerros receberam colostro e/ou leite de vacas soropostivas, aquecido à 560C por 30 minutos. Dos 13 bezerros que ingeriram colostro e/ou leite de vacas soronegativas, somente um apresentou reação soropositiva durante todo o período considerado, e neste caso, não se descartou a possibilidade de transmissão através de vetores, onde infecção transplacentária, uma vez que, este bezerro era filho de vaca soropositiva. Dos 34 bezerros que ingeriram colostro e/ou leite de vacas soropositivas à LEB, aquecido à 56°C por 30 minutos, dois apresentaram reação soropositiva ao primeiro teste, negativando-se ao reteste, e cinco ficaram reagentes após a desmama. Ao final do estudo, verificou-se que 79,16% dos bezerros desmamados deste grupo, apresentaram reações soronegativa a prova de IDGA. Adotou-se ainda neste rebanho, como medidas de controle da LEB, a separação dos bezerros em grupos soronegativos e soropositivos à prova de IDGA; uso individual de agulhas nas colheitas de sangue, medicações e vacinações; lavagem e desinfecção dos instrumentos cirúrgicos com iodofor e controle de insetos hematófagos, através da distribuição adequada de dejetos orgânicos oriundos da limpeza do curral. A prevalência da LEB no rebanho diminuiu significativamente (P < 0,01) durante O período estudado, de 70,19% para 38,18%. Apesar das dificuldades operacio nais verificadas no decorrer do estudo, tais como, prática não definida de descarte, falta de medidas rigorosas na entrada e saída de animais do rebanho e inadequada infra-estrutura de campo, os resultados alcançados podem ser considerados satisfatórios. Concluiu-se que, a intervenção sobre as variáveis relacionadas a transmissão horizontal da LEB determinou a redução da prevalência da LEB no rebanho no período estudado

The paper describes in detail the application of a vibration-based structural health monitoring system installed in the “San Pedro Apostol” church of Andahuaylillas located in Cusco (Peru), a 16th century adobe church considered a representative example of South America baroque architecture. The results of three years of long-term vibration and temperature and humidity monitoring program are reported in detail in the paper, with a focus on the long-term and short-term correlations between natural frequencies and environmental parameters. The results demonstrate that an accurate estimation of the first eight frequencies in the range 2-6 Hz is possible in the case of complex adobe structure and the existence of an annual cyclical behavior of the natural frequencies with a clear correspondence with the changes in environmental conditions due to seasonal influences. The performed correlations of ambient conditions and structural parameters confirmed the presence of different timescales and their not negligible influence in the case of a vibration-based structural health monitoring assessment of adobe systems with large thermal inertia large thermal inertia.

The paper presents a strategy for the non-linear dynamical analysis of ancient masonry structures through two case studies ("Maniace Castle" in Syracuse, Italy and the Qutb Minar in Delhi, India)., (undefined)