Journal articles on the topic 'Riveted members'

The work describes the effect of the atmospheric corrosion upon the mechanical properties of blind rivets. The subject of given research is: corrosion of metal materials, system resistance, design modification and others means of prevention against the corrosion attack. The problem of blind rivets, blind rivet setting, setting equipment, terminology and definitions, characteristic, and special blind rivet setting is also analysed. The experiment itself, the experimental method and the evaluation of the test are described. Mechanism of riveted joint damage produced by galvanic corrosion is proposed. Considerable corrosion damage occurred at combination of the joint members and connected materials with different electrochemical potentials. Exposition to the corroding environment produces release of rivet clam, together with decrease of rivet stiffness. The proof of these mechanisms is documented by functional dependence F – ∆L and metallographic tests.

The renovation or replacement of existing steel bridges in North America is a topic of increasing importance. Because most older structures used riveted connections, rather than the bolted or welded connections that are common today, information on the fatigue life of riveted connections is required for a proper evaluation of the structure.The study reported herein provides a summary and evaluation of the existing data on the fatigue strength of riveted connections, and reports on the results of fatigue tests on some highway bridge members taken from service. Fatigue tests were also carried out on new material containing unfilled holes, both as a reference for riveted connections (rivets with zero clamping force) and with respect to new work in which misplaced holes might be present. The beneficial effect of filling misplaced holes with high-strength bolts is noted. Key words: bolts, failure, fatigue, holes, steels.

According to the fatigue damage failure mechanism of riveted members, a riveted member probabilistic fatigue failure model (RMPFFM) was proposed, and a fracture finite element program is developed to calculate the geometry function of RMPFFM. Furthermore, a system fatigue damage reliability model of riveted bridges was proposed, and based on Monte-Carlo method, a large system fatigue damage reliability analysis program was developed to calculate the system fatigue failure probability. Then the system evaluation model was used to predicate the system fatigue damage reliability of Ganjiang Railway Bridge. According to assessment results, the probabilistic remaining fatigue life, safe inspection intervals and maintenance strategy are determined, which can control and avoid fatigue failure accident and reduce the contingent disaster in bridge service life.

This paper aims to evaluate the fatigue life of an existing railway riveted steel bridge. Based on the measured train load information, the current load spectrum of the bridge is obtained, and the stress histories and stress spectrum of main members of the bridge are achieved using FE model and rain-flow counting method. The fatigue life of the bridge using traditional method is evaluated. At the same time, the finite element (FE) model of riveted component is established and the stress intensity factor of crack tip is calculated. The fatigue crack is simulated on the basis of linear elastic fracture mechanics (LEFM), and the fatigue life of the main members is also evaluated based on the damage tolerance analysis method. The evaluated results of fatigue life show that the fatigue remaining life of the bridge is very long due to the lower live load stress level.

The remaining fatigue life of riveted structures is a topic of considerable importance, particularly for owners of bridges. Improved methods for the estimation of the actual fatigue life of such structures are required in order to make their continued safe use possible while at the same time avoiding the expense of unnecessary repairs. To evaluate the fatigue life expectancy of a structural detail, it is necessary to obtain an accurate estimate of the stress history. Two analytical models are assessed through comparison with measured strains taken from a bridge in service. The results illustrate that a simple model with pinned connections is adequate for the determination of stresses in truss members and that more advanced analysis methods give only marginal increases in accuracy. Stresses in the floor system are most accurately predicted by a model that has full bending moment continuity between connected members. Standard and advanced methods of fatigue life evaluation are discussed and are then implemented in the evaluation of the remaining fatigue life for components of the bridge. Comparison with the actual fatigue life of the components, which were obtained from laboratory experiments, shows that both prediction methods give reasonable estimates of the fatigue life.Key words: bridge, fatigue, rivets, steel, model, analysis.

Abstract The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

Steel corrosion is one of the most dominant factors in the degradation of transport infrastructure. This article deals with the impact of the atmospheric corrosion of structural steel on the load-carrying capacity of old riveted bridge structures. A study on the impact of corrosion losses on the resistance and, thus, the load-carrying capacity of eight chosen bridge members with riveted I-sections from three different bridge substructures is presented. The load-carrying capacity calculation is carried out using modern procedures and on the basis of the diagnosed state of the structural elements. Within the analysis of the results, the need for long-term in situ corrosion measurements, as well as the need for regular inspections on the existing bridges are also discussed.

A common problem associated with many engineering structures is the low damping capacity making it unsuitable for use in aerospace and related structures requiring high dynamic stiffness. Attempts have been made by many researchers to design and fabricate structures, which can contribute substantial damping to the structures. One of the techniques used for this purpose is the layered structure jointed with rivets because of its superiority with respect to the requirements of high damping capacity and stiffness compared to a solid one. The presence of joints in such structures allows slip, thereby increasing the inherent damping of the structures due to interface friction. An attempt has been made in the present investigation to study, both numerically and experimentally, the damping mechanism and methodologies adopted in the structures jointed with rivets for enhancing their damping capacity. This is particularly important in applications such as bridges, pressure vessels, building, aircraft and aerospace structures, and frames and machine members, where damping capacity is of primary consideration.

Results from monotonic and quasi-static cyclic tests on connections used in heavy timber construction are presented for two types of fasteners: steel bolts and glulam rivets. Bolted connections with three different diameter bolts, arranged in several configurations, as well as two different configurations of glulam rivet connections were tested. All configurations included a main glulam member and two steel side plates. For bolted connections, the seismic behaviour was found to be primarily dependent on the bolt slenderness ratio. Bolted connections with higher slenderness ratios (smaller diameter bolts) exhibited more ductile behaviour with considerable steel yielding and wood crushing before failure. Glulam riveted connections, which were designed in rivet failure mode, showed superior seismic performance when compared to bolted connections for similar design load levels. Riveted connections were also able to dissipate the highest amount of input energy before the failure was reached.Key words: timber connections, glulam rivets, bolts, ductility, timber, wood, braced frames, seismic performance, heavy timber construction.

To overcome the low room temperature formability of AA7075-T6 aluminum sheet, without sacrificing the high strength properties of this alloy, a hat section beam member was formed and quenched within a cold die immediately after a 20 minute solutionizing treatment. Natural aging for 24 hours followed the forming process which was then followed by various heat treatments that included a typical precipitation hardening (PH) and industrial paint bake (PB) temperature-time treatment. Tensile specimens were extracted from the beams to evaluate their mechanical properties. When compared to the as-received AA7075-T6 mechanical properties, the beams heat treated with the PH, PHPB and PB treatment resulted in a 5%, 13% and 20% reduction in ultimate tensile strength respectively. A similar trend was shown for the yield strength measurements. There was little effect of the heat treatments on the total elongation, with the PH condition showing a slight improvement. A backing plate was riveted to the beams and a quasi-static 3 point bend test was conducted to evaluate the crush performance. The peak load for the PH, PHPB and PB beams was 9.2, 8.5 and 7.3 kN respectively, but the calculated energy-displacement (or energy absorption) curves were similar for the PH and PHPB parts due to a more ductile fracture behavior for the PHPB material condition.

The Blue Nile Steel Bridge over the Blue Nile River in Khartoum, Sudan, has been in service for 112 years. A riveted steel through-truss of Pettit Configuration with seven equal fixed spans of 65.53 m and a rolling lift span. The bridge currently accommodates approximately 61,000 vehicles per day along with insignificant pedestrian and railway traffic. Over the years from 1960 to 2014 several assessment studies were carried out by numerous parties have revealed that under cyclic loading of a long period time and effects of natural and man-made disasters, bridge deck was damaged severely and needed to be repaired and strengthened. A rehabilitation program was planned to extend the design life of the bridge for a more 50 years, which was carried out in period (2017 - 2018).This paper presents as a case study including a literature review on fatigue assessment of stringers on railway track. The rationale for selecting the rehabilitation strategy for the bridge is described, highlighting the challenging design aspects related to fatigue assessment, clarifying the methodology in which main members were identified for strengthening, using Midas Civil 2006 v7.01 and Midas FEA 2016 v1.1software to analyze the fatigue in the critical members by generating a model using Finite Element Method and estimating remaining fatigue life by adopting the classical approach (Stress-life method), the total damage accumulation was found greater than 1. Thus, it can be concluded that the stringers have no remaining fatigue life. Strengthening the stringers is considered the most favorable solution.

In the pursuit of a lighter composite wing design, fast and effective methodologies for sizing and validating the wing members (e.g., spar, ribs, skins, etc.) are required. In the present paper, the preliminary design methodology of an airliner main composite wing, which has an innovative multispar configuration instead of the conventional two-spar design, is investigated. The investigated aircraft wing is a large-scale composite component, requiring an efficient analysis methodology; for this purpose, the initial wing sizing is mostly based on simplified Finite Element (FE) stress analysis combined to analytically formulated design criteria. The proposed methodology comprises three basic modules, namely, computational stress analysis of the wing structure, comparison of the stress–strain results to specific design allowable and a suitable resizing procedure, until all design requirements are satisfied. The design constraints include strain allowable for the entire wing structure, stability constraints for the upper skin and spar webs, as well as bearing bypass analysis of the riveted/bolted joints of the spar flanges/skins connection. A comparison between a conventional (2-spar) and an innovative 4-spar wing configuration is presented. It arises from the comparison between the conventional and the 4-spar wing arrangement, that under certain conditions the multispar configuration has significant advantages over the conventional design.

In the State of Kedah Darul Aman, efforts to guide the muallaf are formally carried out by the Center for Islamic Guidance Abdul Halim of Kedah (PUSBA) under the administration of the Kedah State Islamic Religious Council. PUSBA conducts guidance classes on the basic principles of Islam in an effort to ensure that they can remain in Islam by practicing its true teachings. A question arises on whether this guidance also helps in increasing their knowledge and in appreciation of the Islamic principles. This paper will analyse one of these principles, in terms of prayer guidance. The study uses the Context, Input, Process, Product Evaluation Model (CIPP) which focuses on process evaluation, through the exploration of the practice of prayer teaching among members of the PUSBA community. This study is qualitative and employs face-to-face interview techniques in data collection. The results showed that there are two forms of guidance programs, the monthly program for four months conducted at PUSBA, and another open weekly program for muallaf who could not attend the monthly program. The teaching method of prayer guidance is carried out in the form of lectures, demonstrations, exercises, questionnaires and techniques concurring with the level and ability of the trainees. This study proposes that a more in-depth study of this teaching process be conducted to better understand the teaching process, whose additional inputs gained will further enhance the teaching process at PUSBA.

In recent years, the application of fiber-reinforced plastics (FRPs) as structural members has been promoted. Metallic bolts and rivets are often used for the connection of FRP structures, but there are some problems caused by corrosion and stress concentration at the bearing position. Fiber-reinforced thermoplastics (FRTPs) have attracted attention in composite material fields because they can be remolded by heating and manufactured with excellent speed compared with thermosetting plastics. In this paper, we propose and evaluate the connection method using rivets produced of FRTPs for FRP members. It was confirmed through material tests that an FRTP rivet provides stable tensile, shear, and bending strength. Then, it was clarified that non-clearance connection could be achieved by the proposed connection method, so initial sliding was not observed, and connection strength linearly increased as the number of FRTP rivets increased through the double-lapped tensile shear tests. Furthermore, the joint strength of the beam using FRTP rivets could be calculated with high accuracy using the method for bolt joints in steel structures through a four-point beam bending test.

The efficiency of glulam rivets has made them one of the most suitable connectors in heavy timber construction utilizing glued-laminated timber (glulam) members. Starting with the 1994 version of the CSA Standard for Engineering Design in Wood, design procedures are also available for the use of glulam rivet connections with sawn timbers. In the course of formulating these design provisions, several series of lateral resistance and withdrawal tests were performed using glulam rivets with sawn timbers to study the effects of material (sawn timber versus glulam), species, loading type and direction, environmental conditions, density, waiting period between assembly and test, pre-drilling, and plate thickness. The newly added design provisions increase structural engineers' choice of fastening systems in timber construction.Key words: glulam rivets, fasteners, connections, timber.

The 1984 edition of the Canadian Standards Association Standard 086 restricts the use of glulam rivets to Douglas-fir– larch glued-laminated timber (glulam) only. This study, undertaken in order to extend the use of glulam rivets to both spruce glulam and solid timber, presents the results from the short-term ramp testing of 33 glulam rivet connections assembled using white spruce and Douglas-fir glulam beams and Douglas-fir solid wood joists. Half of these connections were tested to failure with load applied parallel to the grain of the wood member; the other half were tested with load applied perpendicular to the grain. A species factor of 0.80 is recommended for application to the design values of Douglas-fir–larch glulam rivet connections in order to obtain values for spruce glulam rivet conne-ctions. Also, small (less than 4%) differences were found between the lateral load-carrying capacities of glulam rivet connections made with Douglas-fir glulam and connections made with Douglas-fir solid timber free from major checks and (or) splits. To provide theoretical representations of the load–slip curves of the experimental treatment groups, an exponential function was fitted to the test data. Key words: glulam rivet, timber engineering, fasteners, nails, glued-laminated, wood connectors.

A new design approach to evaluate the resistance of bolted timber connections loaded perpendicular-to-grain is presented in this paper. The design method consists of calculating the resistances of the ductile failure modes, based on the original European yield model, and that of the splitting mode, and of using the smallest of the two. The splitting calculations are adapted from the wood resistance calculation for timber rivet connections. The new design method is based on the assumption that the bolted connection is forming a cluster considered to be equivalent in dimension to a cluster of timber rivets. The rivet design equations were modified to reflect the fact that bolts extend to the full thickness of the wood members, whereas rivets do not. In this paper, the research program is described, results are presented and the alternative design approach is proposed to predict the failure modes and the ultimate strengths of steel–wood–steel, wood–wood–wood, and wood–steel–wood bolted connections.Key words: connections, strength, design, bolt, connection, prediction, failure, perpendicular-to-grain.

This paper proposes a new joining approach for dissimilar materials, called ‘the fastenerless-riveting,’ employing the friction stir forming (FSF). The FSF is a friction stir process invented by Nishihara in 2002. In FSF, a substrate material was put on a die firstly. Next, friction stirring was conducted on the back surface of the material. The material then deformed and precisely filled the cavity of the die due to high pressure and heat caused by the friction stirring. The authors utilized the FSF approach to generate rivet like joints as followings. First, a substrate which is capable for friction stirring, i.e. an aluminum alloy plate, was put on a dissimilar material plate having holes, i.e. a steel plate. The authors call the former ‘the host member,’ the latter ‘a joined member.’ These members were put on a die having the cavity to fabricate the head of the rivet-like structure. Then FSF was conducted to form the stems and heads of the structure. Joint members are able to be stacked within the forming limit. In the study, the authors firstly conducted the proof of the concept (PoC) tests to generate rivet-like structure between steel and aluminum alloy plate and between CFRP and aluminum alloy plate, then investigated the forming conditions, i.e. tool feed rate, tool pass and the corresponding results, including the volume of the generated stem and head of the individual rivet-like structure. 3mm-thick A5083P-O aluminum alloy plates was utilized as the host member, and a 0.7mm-thick SPCE steel plate and a 0.8mm-thick CFRP plate as the joined members.

A frictional contact model is adopted for the analysis of conventional solid rivet setting. Material properties for the selected plates and rivets are obtained from analytical method using elastic constants and tensile strengths for each material. Rigid- and elasto-plastic models are selected for process analysis in this paper. Process variables are selected to investigate the effect of variables on the successful rivet setting and servicing in any structure as force transmitting member. Major variables in riveting process are material variables such as material properties and geometrical variables, which are dimensions of head, shank, and blank diameters. Analysis in this study is concentrated on the influence of variety of materials and of shank dimensions on the contact area after rivet setting, i.e. after forming process of rivet head. Soft and hard materials are selected as mother materials to investigate how the selection of material influences on the riveting process in quantitative manner. The geometry of head is closely investigated through simulation in terms of contact status, i.e. contact area between rivet head and mother material, which would affect the snap fit joint by riveting.

In order to study the progressive collapse resistance of the panel-rod composite latticed shell, a static test was performed on two latticed shells with the same size, one of which was removed a key member. The results of experiments and numerical simulations show that the composite reticulated shells were damaged due to the fracture of some members and the shearing of some rivets. Compared with the complete latticed shell, the bearing capacity of the latticed shell which was removed a key member did not decrease too much, but its displacement of the joints increased significantly. The phenomenon indicated that the removal of the key member had a certain effect on the progressive collapse resistance of the composite latticed shell. The key members of the composite latticed shell must be locally strengthened.

The overall number of railcars recorded in the North American railcar fleet from 2010 to 2015 increased about 5%; the number of all 130 tonne (286,000 lb) gross weight railcars (heavy axle load (HAL) railcars) increased 19%. The increase in shipments in short railcars increases the loading on railway bridges, especially the 12.8-m railcars, commonly used to ship sand and cement, which is approximately a 25% increase in load per unit length compared to 16.2-m coal cars. Significant differences between maximum effects of shorter railcars and common 16.2-m railcars were predicted in analysis for bridge spans longer than 18.3 m. The differences were more prominent on spans 24.4 m and longer. This study presents analytical and measured effects of freight railcars on a two-span truss bridge, with spans of 61 m and 33.5 m, and a 35-m riveted steel deck plate girder (DPG) bridge. The investigation confirmed that short railcars cause higher load effects on main bridge components: the 35-m riveted steel DPG has 28% higher stresses at mid-span, while in the truss, the difference in stresses depends on the location of the member and ranges from 15 to 35%.

Fibre composite guardrails are increasingly being used due to its high strength, high corrosion resistance and low maintenance, although there is very limited information on their structural behaviour. In this study, full-scale pultruded glass fibre reinforced polymer guardrail is experimentally investigated to have a better understanding on the behaviour of fibre composites guardrail system. Glass fibre reinforced polymer guardrail systems mounted on top and side of a steel beam with different joint connectors are loaded horizontally to top of the guardrail post and to the middle of the guardrail member. The results showed that the guardrail system with joints connected with either polypin or rivets combined with epoxy exhibited 20% higher failure load and almost double the stiffness than those connected using polypin or rivets alone. The side-mounted guardrail failed due to failure of the base connector, while the guardrail mounted on top of the beam failed due to failure of the joint connector. Finally, the results of the study indicated that the structural behaviour of glass fibre reinforced polymer guardrail system is affected mainly by the type of joints connecting the different members.

New data on the Lower Cretaceous Falskebugt Member (Palnatokes Bjerg Formation) and Stratumbjerg Formation in easternmost Wollaston Forland, northern East Greenland, are interpreted here. The type locality of the Falskebugt Member on the north-west corner of the Falkebjerg ridge has been revisited, and additional new good exposures were found in a riverbed just north of Falkebjerg and more in river beds on the plain further to the north, where both the Falskebugt Member and the Stratumbjerg Formation are exposed. Previously, only a limited marine fauna was reported providing a restricted middle Valanginian age of the Falskebugt Member. New fossil faunas in other parts of the Falskebugt Member suggest an early Valanginian – Hauterivian age and confirm lateral correlation with the Albrechts Bugt and Rødryggen Members of the Palnatokes Bjerg Formation. However, in places where the Falskebugt Member is exposed in contact with the lower Stratumbjerg Formation, dinoflagellate cysts from these units indicate Barremian and late Barremian ages, respectively. The stratigraphic range of the combined biostratigraphic data from the Falskebugt Member indicates an early Valanginian – late Barremian age. Dinoflagellate cysts from part of the assemblage in the Stratumbjerg Formation suggest a marginal marine/brackish water depositional environment. Comparable depositional environments are also recorded in upper Barremian sediments on Store Koldewey and in the Ladegårdsåen Formation on Peary Land much farther to the north in Greenland. The dark mudstones of the Stratumbjerg Formation show no potential for generation of liquid hydrocarbons, and the immature and poorly sorted sediments of the Falskebugt Member have little potential as a petroleum reservoir.

The theologian and politician Bodil Koch was an influentialplayer in politics regarding the Danish national church in the 20th century.During her twenty-four years as MP for the Social Democrats shemade an effort to avoid an independent constitution of the Church anda separation of church and state. During her thirteen years as Minister ofEcclesiastical Affairs she worked to adjust the church to the welfare state.This article examines one of her initiatives: A commission to modernizethe structure of the church. The surveys and studies from the commissionintroduced methods from sociology and social science into the fieldof church politics in Denmark. The work focused on the activities of thechurch and it revealed a scarce knowledge of traditional Christianityamong the members as well as low Church attendance. Thus the introductionof social science in the ecclesiastical sphere reinforced public notionsof a gap between the Danish national Church and the Danish population– against all intentions.

The adaptation to adverse environmental conditions can lead to adapted microbial communities that may be screened for mechanisms involved in halophily and, in this case, metal tolerance. At a former uranium mining and milling site in Seelingstädt, Germany, microbial communities from surface waters and sediment soils were screened for isolates surviving high salt and metal concentrations. The high salt contents consisted mainly of chloride and sulfate, both in soil and riverbed sediment samples, accompanied by high metal loads with presence of cesium and strontium. The community structure was dominated by Chloroflexi, Proteobacteria and Acidobacteriota, while only at the highest contaminations did Firmicutes and Desulfobacterota reach appreciable percentages in the DNA-based community analysis. The extreme conditions providing high stress were mirrored by low numbers of cultivable strains. Thirty-four extremely halotolerant bacteria (23 Bacillus sp. and another 4 Bacillales, 5 Actinobacteria, and 1 Gamma-Proteobacterium) surviving 25 to 100 mM SrCl2, CsCl, and Cs2SO4 were further analyzed. Mineral formation of strontium- or cesium-struvite could be observed, reducing bioavailability and thereby constituting the dominant metal and salt resistance strategy in this environment.

The Triassic Yanchang Formation in the Ordos Basin is one of the main exploration targets. Based on the detailed exploration of the outcrop at the southern margin of the Ordos Basin, combined with previous results, a systematic analysis of lithology, rock assemblage, sedimentary facies characteristics and temporal evolution is carried out. The results show that the Changchang 9 oil-bearing group on the southern margin of the Ordos Basin can be divided into 9 lithofacies types, and three types of sedimentary facies, meandering river, meandering river delta, and braided river delta are developed. The meandering river facies develops riverbed retention deposits, beaches, and There are four types of microfacies in natural dikes and rupture fans. There are five types of microfacies in meandering river deltas: underwater distributary channels, underwater natural dikes, divert bays, estuary dams, and remote sand dams. Braided river deltas develop underwater distributary channels, There are two kinds of microfacies between distributary channels; the Chang 9 oil-bearing group has a coarse-fine-coarse compound rhythm in the vertical direction; meandering river sand bodies and delta front sand bodies are the main places for oil and gas migration and accumulation.

Fibre composite guardrails are increasingly being used to ensure safety of workers from fall-from-height incidents due to its high strength, high corrosion resistance and low maintenance. In this study, the structural behaviour of pultruded glass fibre-reinforced polymer (GFRP) guardrail was evaluated following AS1657-1992. GFRP guardrail systems mounted on top and side of a steel beam with different joint connectors are loaded horizontally to top of the guardrail post and to the middle of the guardrail member. The results showed that the guardrail system with joints connected with either polypin or rivets combined with epoxy exhibited 20% higher failure load and almost double the stiffness than those connected using polypin or rivets alone. The side-mounted guardrail failed due to failure of the base connector while the guardrail mounted on top of the beam failed at the joints indicating that the structural behaviour of GFRP guardrail system is affected mainly by the type of joints.

Enterococcus faecalisis a commensal and pathogen of humans and insects. InManduca sexta,E. faecalisis an infrequent member of the commensal gut community, but its translocation to the hemocoel results in a commensal-to-pathogen switch. To investigateE. faecalisfactors required for commensalism, we identifiedE. faecalisgenes that are upregulated in the gut ofM. sextausing recombinase-basedin vivoexpression technology (RIVET). The RIVET screen produced 113 clones, from which we identified 50 genes that are more highly expressed in the insect gut than in culture. The most frequently recovered gene was locus OG1RF_11582, which encodes a 6-phosphogluconolactonase that we designatedpglA. ApglAdeletion mutant was impaired in both pathogenesis and gut persistence inM. sextaand produced enhanced biofilms compared with the wild type in anin vitropolystyrene plate assay. Mutation of four other genes identified by RIVET did not affect persistence in caterpillar guts but led to impaired pathogenesis. This is the first identification of genetic determinants forE. faecaliscommensal and pathogenic interactions withM. sexta. Bacterial factors identified in this model system may provide insight into colonization or persistence in other host-associated microbial communities and represent potential targets for interventions to preventE. faecalisinfections.

Abstract. The large difference in the fractionation of stable carbon isotopes between C3 and C4 plants is widely used in vegetation reconstructions, where the predominance of C3 plants suggests wetter and that of C4 plants drier conditions. The stable carbon isotopic composition of organic carbon (OC) preserved in soils or sediments may be a valuable (paleo-)environmental indicator, based on the assumption that plant-derived material retains the stable carbon isotopic value of its photosynthetic pathway during transfer from plant to sediment. In this study, we investigated the bulk carbon isotopic values of C3 and C4 plants (δ13C) and of organic carbon (δ13Corg) in soils, river suspended particulate matter (SPM) and riverbed sediments to gain insight into the control of precipitation on C3 and C4 plant δ13C values and to assess changes in δ13Corg values along the plant–soil–river continuum. This information allows us to elucidate the implications of different δ13C end-members on C3 / C4 vegetation reconstructions. Our analysis was performed in the Godavari River basin, located in the core monsoon zone in peninsular India, a region that integrates the hydroclimatic and vegetation changes caused by variation in monsoonal strength. The basin has distinct wet and dry seasons and is characterised by natural gradients in soil type (from clay-rich to sandy), precipitation (∼ 500 to 1500 mm yr−1) and vegetation type (from mixed C3 / C4 to primarily C3) from the upper to the lower basin. The δ13C values of Godavari C3 plants were strongly controlled by mean annual precipitation (MAP), showing an isotopic enrichment of ∼ 2.2 ‰ from ∼ 1500 to 500 mm yr−1. Tracing δ13Corg values from plant to soils and rivers revealed that soils and riverbed sediments reflected the transition from mixed C3 and C4 vegetation in the dry upper basin to more C3 vegetation in the humid lower basin. Soil degradation and stabilisation processes and hydrodynamic sorting within the river altered the plant-derived δ13C signal. Phytoplankton dominated the δ13Corg signal carried by SPM in the dry season and year-round in the upper basin. Application of a linear mixing model showed that the %C4 plants in the different subbasins was ∼ 7 %–15 % higher using plant end-members based on measurement of the Godavari vegetation and tailored to local moisture availability than using those derived from data compilations of global vegetation. Including a correction for the 13C enrichment in Godavari C3 plants due to drought resulted in maximally 6 % lower estimated C4 plant cover. Our results from the Godavari basin underline the importance of making informed choices about the plant δ13C end-members for vegetation reconstructions, considering characteristics of the regional vegetation and environmental factors such as MAP in monsoonal regions.

ABSTRACTEnterococcus faecalisis a member of the mammalian gastrointestinal microflora that has become a leading cause of nosocomial infections over the past several decades.E. faecalismust be able to adapt its physiology based on its surroundings in order to thrive in a mammalian host as both a commensal and a pathogen. We employed recombinase-basedin vivoexpression technology (RIVET) to identify promoters on theE. faecalisOG1RF chromosome that were specifically activated during the course of infection in a rabbit subdermal abscess model. The RIVET screen identified 249 putativein vivo-activated loci, over one-third of which are predicted to generate antisense transcripts. Three predicted antisense transcripts were detected inin vitro- andin vivo-grown cells, providing the first evidence ofin vivo-expressed antisense RNAs inE. faecalis. Deletions in thein vivo-activated genes that encode glutamate 5-kinase (proB[EF0038]), the transcriptional regulator EbrA (ebrA[EF1809]), and the membrane metalloprotease Eep (eep[EF2380]) did not hinder biofilm formation inin vitroassays. In a rabbit model of endocarditis, the ΔebrAstrain was fully virulent, the ΔproBstrain was slightly attenuated, and the Δeepstrain was severely attenuated. The Δeepvirulence defect could be complemented by the expression of the wild-type gene intrans. Microscopic analysis of early Δeepbiofilms revealed an abundance of small cellular aggregates that were not observed in wild-type biofilms. This work illustrates the use of a RIVET screen to provide information about the temporal activation of genes during infection, resulting in the identification and confirmation of a new virulence determinant in an important pathogen.

The bivalve genus Galatea Bruguière, 1797 (Venerida: Donacidae) was thought to contain exclusively brackish-water clams, the ranges of which are confined to estuaries and lower tidal parts of large rivers in West Africa. This genus was therefore included to the global freshwater bivalve checklists (Bogan 2013; Graf 2013) as a largely estuarine group. Conversely, a review of published data alongside our field surveys indicate that at least three populations of Galatea spp. largely occur in freshwater environment, i.e. those from the Sanaga (Cameroon), Niger (Nigeria), and Volta (Ghana) rivers. The systematic placement of these populations is unclear, as are the taxonomic status and validity of numerous nominal taxa described in this genus from a variety of localities throughout the Atlantic Coast of Africa (Angola to Senegal). We tentatively assign the populations from Niger and Volta to Galatea paradoxa (Born, 1778), while the Sanaga’s population is considered here as Galatea schwabi (Clench, 1929). However, these taxa do not share clear morphological differences and may belong to a single widespread species. In this study, we present the first DNA sequence data for a Galatea member, i.e. G. schwabi. Our COI phylogeny supports its placement within the family Donacidae suggesting sister relationships between Galatea and Donax Linnaeus, 1758. Most Galatea populations play a vital role for local riparian communities in West Africa as an intensively exploited food source. Furthermore, the clams are heavily threaten by anthropogenic impacts such as dam construction, riverbed substrate mining, and river pollution. The fishing loads and habitat degradation altogether lead to the rapid decreasing of Galatea populations in several water bodies, e.g. the Volta River in Ghana. It is impossible to develop conservation and management plans for these clams due to the lack of reliable species-level taxonomic concept of the genus. It is clear that the Galatea taxonomy and ecology need a thorough revision in the future based on DNA sequences of newly collected samples from all West African rivers, in which these remarkable clams occur.

Background of the study. Due to the increasing intensity and frequency of catastrophic floods occurrence, one of the most important tasks of the water management of Ukraine is to increase the efficiency of the existing system of flood protection due to the implementation of integrated flood risk management methods based on the assessment of flood hazard levels requirements according to Directive 2007/60/EC. The development of scientific and methodological bases for the assessment and mapping of flood hazard and risk levels, as well as the development of integrated flood risk management plans based on them, is an important and urgent task in Ukraine as an associated EU member. The purpose of the work is to highlight the main works results, performed at the Institute on the study of patterns of riverbed transformations, the development of strategies for flood risk management and scientific and methodological support of the assessment and mapping of flood hazard and risk, taking into account the nature and the intensity of river bed transformation and exogenous processes in river basins of Ukraine. Outline of the main material. Systematic research on flood protection issues and river bed evolution in IWPaLR has been conducted since the middle of the last century. The problems of the dynamics of river bed’s evolutions, ensuring the stability of dams, erosion of the tail water of dam, development of active hydraulic structures and their arrangement in river beds, forecasting river bed evolution, runoffs, development study of permissible (nondestructive) flow velocities for alluvial soils, taking into account the phenomenon of self-patching of the river bed, the dynamic equilibrium of the beds, the typing of the beds of mountain rivers, etc., were studied and solved under the natural conditions and in the hydraulic laboratory of the Institute. Based on the results of theoretical and experimental studies of river bed evolution, a number of methodological provisions on the complex regulation of channel deformations and safe passage of high floods were formulated and published a number of regulatory and methodological documents on the calculation and forecasting of river bed transformations, designing of dams and protection structures. An important role was given to the issues of regulation and redistribution of floodwater by the system of river reservoirs and replenishment of groundwater reserves. The methodological recommendations for sampling of river bed deposits and sediments, on the base of the international ISO standards’ requirements and recommendations of have been developed at the Institute, as well as the method of estimation of the river bed transformation’s dynamics, for the discrete and quantitative assessments of river bed deformations and their intensity. The paper also highlights the main results of work on the implementation of the Flood Directive 2007/60/EC in Ukraine, in particular, the development of a Flood Risk Management Strategy in the Ukrainian Carpathian River basins. In the Strategy declared the latest approaches to flood response, which foresee the abandonment of the current paradigm of "flood protection" to favor integrated flood risk management. It defines national mechanisms of strategic management in the field of flood risk reduction, directions of transboundary cooperation, coordination of works within river basins. For the future development of this Strategy, the paper presents the scientific and methodological bases for a comprehensive assessment of the total levels of flood hazard and flood risk and their mapping on a GIS basis. Conclusion. In the future, scientific research on integrated flood risk management should focus on the study of patterns of evolution of river bed and development of mathematical models of regulation of channel deformations, improvement of the flood forecasting and prevention methodology based on simulation modeling, as well as the development new management schemes for runoff ‘s regulation.

To improve the efficiency and performance can be achieved by decreasing the aircraft weight through considerable usage of composite material in primary aircraft structures. In fuselage construction it consist of various structural members such as skin, stringers, frames, bulkheads etc., all fastened together by rivets and bolts. The failure of riveted joint take place when tearing of the plate, shearing of rivets and plate under the action of over load. This project deals with the tensile strength analysis of riveted lap joints of three different composite materials such as Glass fiber, Basalt fiber and Carbon fiber are reinforced with epoxy resins. By using universal testing machine the tensile strength of the riveted single lap joint of three different composite materials are tested experimentally.

Most of the research on hybrid natural fiber composites has been focused on non-structural applications. The aim of this research is to improve the understanding of how to use hybrid natural fiber composites for structural applications, such as in the aerospace and automotive industries. The joining of subassemblies with rivets, bolts, or screws is a prominent feature in these industries, which implies that the presence of holes in the structural members is unavoidable. The study of the effect of holes on the mechanical behavior of these members is therefore imperative, especially given that holes are stress risers. An important factor in the design of open-hole hybrid flax composites is their fatigue behavior under cyclic loading because it accounts for most failures in composite structures. The investigation of this behavior is reported in this study where three types of 16-ply symmetric hybrid composites that were manufactured using woven carbon (C) and unidirectional flax (F), namely, unidirectional (CF[0]), cross-ply (CF[0/90]) and angle-ply (CF[[Formula: see text] 45]) are employed. A circular hole was made in the center of each specimen using either an abrasive water jet or conventional drilling methods. The observed machining-induced critical defect was delamination, which manifested in three forms: peel-up, push-out, and secondary. Stepwise fatigue tests were conducted to determine the damage evolution and high-cycle fatigue strength of each layup. The damage evolution of the material was assessed via stiffness damage, thermographic methods, and dissipated energy per cycle. It was observed that CF[0] layups are unaffected by the machining process and they have an identical high-cycle fatigue strength. For the CF[0/90] and CF[[Formula: see text] 45] layups, conventional drilling specimens have a higher high-cycle fatigue strength than their abrasive water jet counterparts.

Abstract In 2019, an Extraordinary General Assembly International Council of Museums (ICOM) met in Kyoto, Japan to vote on a new museum definition. Among other things, the controversial proposal described museums as “democratising, inclusive and polyphonic spaces for critical dialogue about the pasts and the futures” that should also aim “to contribute to human dignity and social justice, global equality and planetary wellbeing.” The motion to postpone the vote, which was supported by a large majority in Kyoto, caused a crisis in the most important international organization for museums and museum professionals. In the years since, ICOM Define led an elaborate consultation process resulting in a newly revised museum definition to be voted on at ICOM’s Extraordinary General Assembly in Prague in August 2022. In this conversation, several prominent members of ICOM who have been deeply involved in the debates about a new museum definition take a critical look at the consultation process before Kyoto, the reasons for postponing the vote, the work of ICOM Define, and also share their expectations for Prague.

AbstractAs an increasingly important aspect of water management, historical dry river-channels, ponds or lakes are operated for the storage of reclaimed water as a landscape with the need for reuse of water. However, the percolated reclaimed water may have an adverse effect on groundwater quality. The aims of this work are to evaluate the potential for using various groundwater constituents or characteristics as tracers of percolated reclaimed water, to clarify the groundwater hydrochemical process with the effect of the reclaimed water recharge, and to estimate the degree to which the infiltrated reclaimed water has mixed with the native groundwater. Results obtained by comparing analysis between the dry season and wet season are presented based on multivariate statistics analysis, correlation of hydrochemical elements, and stable isotopes. The groundwater with the impact of reclaimed water was clustered together with higher Cl, K and NH4–N concentrations, lower Ca concentrations and more enriched heavy isotopes using unprecedentedly 3D-biplot; The water types of the groundwater change from Ca–Mg–HCO3–Cl, via Ca–Na–Mg–HCO3–Cl to Na–Ca–Mg–Cl–HCO3 with increasing reclaimed water percolated into the groundwater; the most useful tracers for evaluation of the fate and mixing of reclaimed water are chloride ion and oxygen-18 and chloride ion is more accurate than oxygen-18 to quantify the recharge source of the groundwater from the reclaimed water; using a two-end-member mixing model to calculate the reclaimed water discharged into the groundwater, the proportion of reclaimed water in groundwater is up to 94% near the unlined riverbed and up to 43% far from it. These results demonstrate the potential of the combined application of multivariate statistics analysis, traditional hydrochemical analysis and isotopes to assess the percolated reclaimed water in the groundwater, especially using 3D-biplot to determine the spatial water quality changes defined by the different factors.

Historic-Archaeological Research of the Catholic University of the Sacred Heart of Milano on the Indus Delta (2010-2018). The following text is only an abridged note on the excavations at Banbhore and some significant extra-moenia surveys carried out by the Italian Team within the Institutional framework of a “Pak-French-Italian Historical and Archaeological Research at Banbhore” on the basis of a Licence issued by the competent Pakistani Authorities (2010-2015 - Coordinator of the Project Dr Kaleemullah Lashari), and, some later, within a new institutional asset: a “Memorandum of Understanding” (MoU) signed in the 2017 between the Director General of the Department of Antiquities of Sindh (Manzoor A. Kanasro) and the Magnifico Rettore of the Catholic University of the Sacred Heart of Milan (Prof. Franco Anelli). Aims of the said MoU are: (a) historical-archaeological research-work at Banbhore and Rani Kot; (b) training (theoretical and on the job) to selected students and officers of the DAS. The Italian group works under the sponsorship of the Italian Ministry for Foreign Affairs (now Ministry for Foreign Affairs and International Cooperation/MAECI). Scientific director for the Italian Team is Prof. Valeria Piacentini, member of the Board of Directors of the Research Centre CRiSSMA of the Catholic University. In the following dissertation I won’t linger on the debated issue about the identification of the site of Banbhore with historic sites on the Indus delta (the historical Mihrān river) mentioned and described in the written sources of the past. Too many respected scholars and archaeologists have entered this debate since the end of the 19th Century, for which I refer to a well-known exhaustive literature. In the “50s of the previous century, Leslie Alckok – then official to the Department of Archaeology of Pakistan – carried out some preliminary excavations, followed by Dr Rafique Mughal and F.A. Khan. This latter carried out a systematic and extensive archaeological campaign of several years between the “50s and the “60s, well backed by one of the most authoritative Pakistani historians, N.A. Baloch. Khan brought to light extraordinary archaeological and architectural evidence, but, unfortunately, his excavation-notes have gone lost and little or nothing has been published. Thence, our research-work had to start from nothing. First of all and most urgent was an updated planimetric and altimetric study of the site by kite-photos: a massive wall of c. 1,4 km with 55 towers, 7 posterns, and major and secondary accesses to the citadel (2010-2012 by Y. Ubelman, S. Reynard, A. Tilia), regularly updated with advanced technologies (A. Tilia). Then, in collaboration with Dr M. Kervran, head of the French Team, we undertook an accurate study of the bastions and the shapes of its towers (squared, U-shaped, circular), which has brought to envisage three main occupational phases of the intra-moenia area: 1. Indo-Parthian/Indo-Kushan phase (c. III-II Century b.CE – III-IV Century CE); 2. Sasanian/Indo-Sasanian phase (c. III-IV Century – early VIII Century CE); 3. Islamic phase (VIII – XII/early XIII Century CE). Decay and/or abandonment and end of any settled life on the site can be dated around the XII-early XIII Century, due to attacks and pillaging by Turco-Mongol nomadic tribes, and/or the deviation of this branch of the Indus delta and consequent filling of the harbour, or both. Archaeological evidence come to light confirms the historical information. Our third aim (2010-2015) was to arrive to a first chronological panorama of the site through levels in stratigraphy and the assemblage of pottery and other significant evidence with the individual levels (N. Manassero – A. Fusaro – A. Tilia). Deep trenches were excavated (T/7 and T/9 on the Italian side; T/1 on the French side near the western portion of the bastions skirting the Hindu Temple. These brought to the very early Sasanian period or late Indo-Parthian (c. II-III Century CE), then the water-table invaded the trenches preventing us to go deeper; however, drillings (T/9) have allowed to go deeper for c.1,8 mt of shards …thus reaching a much earlier occupational phase. The question about an Hellenistic occupation at the bottom of the site (Arrian’s harbour of Alexander) is still unanswered… a dream…but the importance of Banbhore has induced to take it seriously and include it within our priorities. Ours and the French trenches have also produced significant information on the architectural panorama of the site for its earlier periods of life. A main N-S and E-W road axis was traced. The site was organised in insulae, each insula with its pits of organic and inorganic refusals, densely built along narrow roads by small mono-nuclear houses, roofed, bases in local stones and the elevation in unbacked bricks. Interesting the presence of refusals of some crafts, as if each building had at the same time the function of “home” and workshop. The refusals shew activities of ivory-working (T/1,T/4, T/9), and other crafts carried out “within the bastions of the citadel”, such as glass, shells and mother of pearl, alloys and various metallurgic activities, too, and so on. Significant the presence of a wealth of clay-moulds. T/5 has produced a clay-mould nearly intact in its shape. No less interesting, in the deeper layers, the presence of a well arranged organisation of the hydraulic resources (small canals, little domed cisterns in roughly cut local stones, wells..: T/9). One element of the site attracted our attention: the so called “Partition Wall”. It has a North-South direction; then, it bends Eastwards, including the Mosque and the Eastern lagoon, but cutting out the majestic Southern Gate. So far, it had been interpreted as a Wall that had a “religious” or “social” function to separate – after the Islamic conquest – the Muslims from the non-Muslim inhabitants of the site. Manassero dedicated the 2014 Field-Season to investigate: T/7 and T/8 were the trenches that gave a new profile to this structure and to the general occupational organisation of the citadel during its last period of life. The round-shaped tower in mud-bricks and the walls on both sides show that they had been hurriedly erected in a late phase of the life of the citadel (around the end of the X – early XI Century CE). They had been built on the top of pre-existing buildings either abandoned and collapsed or hastily flatted-down, likely to defend this eastern portion of the site and its Mosque by some human ravage that had succeeded to open a breach in the lower western bastion leaving the higher north-eastern area exposed to attacks (the skeleton found by Dr Kervran on her portion of the wall, and Khan’s skeletons with arrow-heads in their skulls and chests). According to F.A. Khan’s excavations and what he left us in his little booklet that so far – printed and re-printed – is the guide for visitors to Banbhore, in the eastern portion of the site during the latest stage of its life still stood beautiful palaces, the Friday Mosque, markets, and an eastern gate where a staircase (still in situ in the 2015) brought to a lagoon at the foot of the eastern bastions and to the river. At the end of this first stage of our historical and archaeological research-work, the identification of the site of Banbhore with the historic Sasanian/Indo-Sasanian fortified harbour-town seemed quite feasible. When we resumed our field-work in the 2017, we decided to go deeper in this direction. In the meantime, Dr Manassero had resigned due to personal choices of life. Dr Simone Mantellini bravely accepted to be our Field-Director for the archaeological sector. T/9 had unearthed an imposing Building (Building 1) running along the East-West road-axis, parallel to a second Building (Building 2). The road – wide about 5 meters – must have been a major road, that had played a central role within the general architectural urban asset of the site. Building 2 had the typical structure of the local houses: base in rough stones, elevation in mud-bricks. Excavations of Building 1 produced fillings well flatted and an endless chronological procession of floors in row mud, likely the re-occupation of an important palace during the last phase of the occupational life of Banbhore. The material (pottery and others) associated with the various levels in stratigraphy (Dr A. Fusaro) confirmed the dating of the dug portion from c. the early XIII to the XI Century CE. Historically speaking, it makes sense: chronicles of the time report about the invasion of Lower Sindh by the Seljuks (second half of the XI Century CE); they indulge on the assaults against the walls of its great harbour-town named Daybul, its long siege concluded with a peace-treaty that fixed the border with Makrān at Gwadar and gave to Daybul an autonomous status (nāḥiya) within the Seljuk dominion of Qāvurd-Khān ibn Chaghrī Beg. More interesting was the copious filling with ivory refusals. Along Building 2, were found semi-worked shells, glass, iron and brass rivets, iron instruments, alloys, coins and other. This induced to think to a late quarter of work-shops outside the Partition Wall, built on previous buildings. Lastly, some surveys extra-moenia and in the Lahiri Bandar and Mullah-ka Kot islands have revealed a close connection and interaction between these spaces and the citadel. Around the bastions: the remains of a densely settled area and a well organised regulation of the waters and the territory, rock quarries, urban quarters, dwellings, cairn-tombs (some of them re-used), an artificial lake of sweet water delimited to the south by a “barrage”, wells, and a vast so called “industrial area” to the north-northwest of the bastions, pottery kilns and others completed the image of a urban asset at least for a given span of time. Architectural and archaeological evidences have regularly been graphically, photographically and topographically documented (A. Tilia). Archaeometric analyses on the job (pottery, metals, alloys, coins…) and in Italy (ivory, glass, clay-moulds, shards…) have provided precious support and new elements to the archaeological work. We are now confronted with the plan of a positive shahristān. Banbhore is no longer only a fortified citadel. Written sources in Arabic and Persian confirm this feature. After the Jan.-Feb. 2018 field-season, the Islamic occupational phase of Banbhore and the “archaeological park” surrounding it enhanced this image: a positive fluvial and maritime system stemmed out, a well-fortified system and harbour-town, a centre of mercantile power, production and re-distribution of luxury goods, an international centre of pilgrimage and religious learning, too, outlet to the sea of the capital-city of the moment. For the forthcoming field-seasons, it was decided to concentrate the attention on the sector where the North-South axis crosses the East-West one. In particular: to further investigate Building 1; to look for the ivory-workshops that must be there around – given the copious pieces so far brought to light and used as refilling (more than 9.000 fragments) and some fragments of rough ivory (specialist of the Italian Team G. Affanni); to organise a deep-trench in the Pakistani sector (T/11), in order to resume Manassero’s investigations on the urban and architectural features of the pre-Islamic phases...and (why not?) try to overcome the water-table problem with the technological support offered by the Bahrya University of Karachi…the much dreamed quest of Alexander the Macedonian’s port. All in all and to conclude. Nowadays, at the end of this first stage of historical and archaeological research-work in collaboration with the DAS, the identification of the site of Banbhore and its surrounding area with the Sasanian/Indo-Sasanian and the Early-Islamic well-fortified harbour-town of Daybul/Debol can be confirmed. No other site with the characteristics described by the written sources of the time (chronicles, geographies, travelogues…plus Marco Polo and some significant Genoese archival documents) has so far come to light on the Indus deltaic region. Conversely, still un-answered are other queries: Banbhore can be identified also with the great harbour of Alexander the Macedonian? Or with the Barbaricum/Barbarikon/Barbariké, harbour-town of Parthian rulers or local lords of “Skuthia”, also mentioned in the Periplus Maris Erythraei? Or again with Dib/Deb, harbour mentioned in a Parthian-Manichaean text? Or again the Dibos of Greek sources? Or the Dêbuhl/Dêphul of an Arminian text à propos of the Prophet Mani? Wishful thinking; however, these queries represent some amongst the ambitious aims of our future research-work.