Structural enhancement of low strength masonry using retro-reinforcement

One of the most effective ways of achieving sustainable construction is to extend the life of an existing structure by repair or strengthening. This needs to be carried out at minimal cost and with minimal disruption to the owners or end users without creating a future maintenance liability. In the case of masonry buildings this can be achieved with the use of retro-reinforcement. Retro-reinforcement involves the installation of small diameter reinforcing bars into pre-cut grooves or pre-drilled holes in the near-surface zones of the masonry that are likely to be subject to tensile stress. The reinforcement usually consists of stainless steel bars to minimise the risk of corrosion. The principal objectives of adding such reinforcement are to improve flexural crack control, increase flexural and shear strength and to increase robustness and ductility. In the UK the technique has been used extensively to strengthen the masonry cladding of low to medium rise buildings, particularly where cracking has occurred adjacent to a long-span window or similar opening. This paper summarises recent experimental research into the behaviour of clay brick wall panels containing 2m and 3m span openings. Single leaf walls with different arrangements of reinforcement constructed using very low strength (1:12 cement:sand) mortar were tested under short-term in-plane vertical loading. Similar plain and retro-reinforced wall panels constructed from natural hydraulic lime (NHL2) mortar were also tested. Some of the panels were constructed to simulate damage (cracking and excessive deflection) that occurs in practice. The retro-reinforced walls showed increases in strength of between 59% and 206% when compared with the unreinforced experimental controls. In addition, the load at which first visible cracking occurred and the reserve of strength beyond first cracking were enhanced

Sustainable built environment design: some lessons from the past

This paper seeks to demonstrate the potential benefits of reflecting on the past with a view to identifying how we might improve in the future. A number of lessons from the past are highlighted. These have been drawn from the author’s experiences as a professionally qualified civil and structural engineer gained from the planning, design, construction, operation, maintenance, repair and strengthening of built environment infrastructure during a period of just over 35 years. Ten main lessons have been identified from a brief review of vernacular construction; other industries; feedback from asset managers; the author’s site experience; strength assessment, repair and strengthening work; multi-disciplinary design challenges; feedback from construction and maintenance specialists and the author’s interaction with various client organisations. The challenge we face as construction professionals is to ensure that these lessons are not forgotten and that appropriate action is taken to improve the service we provide to our clients and to Society, in general

Probing the local dielectric function of WS2 on an Au substrate by near field optical microscopy operating in the visible spectral range

The optoelectronic properties of nanoscale systems such as carbon nanotubes (CNTs), graphene nanoribbons and transition metal dichalcogenides (TMDCs) are determined by their dielectric function. This complex, frequency dependent function is affected by excitonic resonances, charge transfer effects, doping, sample stress and strain, and surface roughness. Knowledge of the dielectric function grants access to a material’s transmissive and absorptive characteristics. Here we use the dual scanning near field optical microscope (dual s-SNOM) for imaging local dielectric variations and extracting dielectric function values using a pre-established mathematical inversion method. To demonstrate our approach, we studied a monolayer of WS2 on bulk Au and identified two areas with differing levels of charge transfer. The experiments highlight a further advantage of the technique: the dielectric function of contaminated samples can be measured, as dirty areas can be easily identified and excluded for the calculation, being important especially for exfoliated 2D materials (Rodriguez et al., 2021). Our measurements are corroborated by atomic force microscopy (AFM), Kelvin force probe microscopy (KPFM), photoluminescence (PL) intensity mapping, and tip enhanced photoluminescence (TEPL). We extracted local dielectric variations from s-SNOM images and confirmed the reliability of the obtained values with spectroscopic imaging ellipsometry (SIE) measurements

Heart and Lung Transplantation in the United States, 1996–2005

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74833/1/j.1600-6143.2007.01783.x.pd

The in vivo study of cardiac mechano-electric and mechano-mechanical coupling during heart development in zebrafish

In the adult heart, acute adaptation of electrical and mechanical activity to changes in mechanical load occur

Soft topographic map for clustering and classification of bacteria

In this work a new method for clustering and building a topographic representation of a bacteria taxonomy is presented. The method is based on the analysis of stable parts of the genome, the so-called “housekeeping genes”. The proposed method generates topographic maps of the bacteria taxonomy, where relations among different type strains can be visually inspected and verified. Two well known DNA alignement algorithms are applied to the genomic sequences. Topographic maps are optimized to represent the similarity among the sequences according to their evolutionary distances. The experimental analysis is carried out on 147 type strains of the Gammaprotebacteria class by means of the 16S rRNA housekeeping gene. Complete sequences of the gene have been retrieved from the NCBI public database. In the experimental tests the maps show clusters of homologous type strains and present some singular cases potentially due to incorrect classification or erroneous annotations in the database

Radial Alignment of Carbon Nanotubes via Dead‐End Filtration

Dead-end filtration is a facile method to globally align single wall carbon nanotubes (SWCNTs) in large area films with a 2D order parameter, S2D, approaching unity. Uniaxial alignment has been achieved using pristine and hot-embossed membranes but more sophisticated geometries have yet to be investigated. In this work, three different patterns with radial symmetry and an area of 3.8 cm2 are created. Two of these patterns are replicated by the filtered SWCNTs and S2D values of ≈0.85 are obtained. Each of the radially aligned SWCNT films is characterized by scanning cross-polarized microscopy in reflectance and laser imaging in transmittance with linear, radial, and azimuthal polarized light fields. The former is used to define a novel indicator akin to the 2D order parameter using Malu\u27s law, yielding 0.82 for the respective film. The films are then transferred to a flexible printed circuit board and terminal two-probe electrical measurements are conducted to explore the potential of those new alignment geometries

A Critical Review of Anti‐Bullying Programs in North American Elementary Schools

BACKGROUNDBullying behavior is a concern among school‐aged youth and anti‐bullying programs have been implemented in schools throughout North America. Most anti‐bullying programs are delivered to adolescent youth because antisocial‐aggressive behaviors are typically associated with this developmental stage. This paper is a review of empirically evaluated school‐based bullying prevention and intervention programs in North American elementary schools.METHODSWe conducted a systematic, critical review of bullying prevention programming. Data were analyzed to determine the study method, intervention components, measurement of bullying, aggression, or peer victimization, outcomes measured, and results.RESULTSOur review resulted in the identification of 10 interventions aimed at youth in grades K‐6 enrolled in North American elementary schools. Effective intervention strategies targeted a variety of bullying behaviors using diverse mechanisms and included a school—and community‐wide approach. Direct outcomes of the reviewed evaluations were centered on bullying, aggression, and victimization. Indirect outcomes of review evaluations included strategies for bystanders, school achievement, perceived school safety, and knowledge or attitudes about bullying.CONCLUSIONSRecommendations for promising practices in effective bullying intervention programming are offered. The review concludes with suggestions for supporting school health staff and in‐service teachers drawn from the body of research, and offers direction for future study.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151360/1/josh12814_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151360/2/josh12814.pd