182 research outputs found

    A Novel Structural Assessment Technique to Prevent Damaged FRP-Wrapped Concrete Bridge Piers from Collapse

    Get PDF
    Repairing deteriorated concrete bridge piers using externally wrapped fiber reinforced polymer (FRP) composites have been proven as an effective approach. This technique has also been applied to low-rise building structures. Failures in FRP-wrapped concrete structures may occur by flexural failures of critical sections or by debonding of FRP plate from the concrete substrate. Debonding in the FRP/adhesive/concrete interface region may cause a significant decrease in member capacity leading to a premature failure of the system. In this chapter, a novel structural assessment technique aiming at inspecting the near-surface FRP debonding and concrete cracking of damaged FRP-wrapped concrete bridge piers to prevent the structures from collapse is presented. In the first part of this chapter, failure mechanisms of FRP-wrapped concrete systems are briefly discussed. The second part of this chapter introduces a novel structural assessment technique in which far-field airborne radar is applied. In this development, emphasis is placed on inspection of debonding in glass FRP (GFRP)-wrapped concrete cylinders, while the technique is also applicable to beams and slabs with bonded GFRP composites. Physical radar measurements on laboratory specimens with structural damages were conducted and used for validating the technique. Processed experimental measurements have shown promising results for the future application of the technique. Finally, research findings and issues are summarized.National Science Foundation (U.S.) (Grant CMS-0324607)Lincoln Laborator

    Practical implications of GPR investigation using 3D data reconstruction and transmission tomography

    Get PDF
    Non-destructive investigation using ground penetrating radar is becoming more popular in the inspection of civil structures. Currently, traditional 2D imaging is used as a preliminary tool to fi nd possible areas of interest for more detailed inspection, which can be accomplished by more advanced techniques like 3D image reconstruction or tomography. In this paper, a general overview of the work done at University of Minho regarding these techniques is presented, together with their limitations and advantages over typical radargrams, with implications for civil engineering applications. For this purpose, data acquisition on two large masonry walls and one large concrete specimen have been carried out, using refl ection mode, 3D reconstruction and transmission tomography. The specimens have been specially built for non-destructive inspection techniques testing, incorporating different materials and internal voids. Radar tomography and 3D image reconstruction techniques provided much more detailed information about structural integrity and shapes and location of the voids, when compared to 2D imaging originally used for potential target identification.Fundação para a Ciência e a Tecnologia (FCT) - POCTI SFRH/BD/6409/2001"Sustainable Bridges" European project - FP6-PLT-0165

    Negative emotions set in motion : the continued relevance of #GamerGate

    Get PDF
    This chapter aims at making sense of the #GamerGate (#GG) online harassment campaign that was particularly active in 2014–2015 but to this day continues to produce hateful speech against certain ideologies and minorities in gaming culture. The campaign was especially successful at building online visibility through harassment, and the affective resonances of the issues it raised have since translated into general online campaigning how-to’s, financial earnings, and even political action outside of the gaming sphere. Although the primary breeding ground for this movement was 4chan (and later, 8chan), it only reached public awareness and visibility – hence, effectiveness – through Twitter and, to a lesser extent, through YouTube. In order to understand the emotional charge and political relevance of this campaign, we rely on both quantitative and qualitative activity analyses of the Twitter users that use the hashtag #GamerGate between 2014 and 2019. In addition to analyzing who were the most active tweeters and what kind of resonance their tweets elicited, we looked into the emotional qualities of their communication. The communication strategies of #GG tweeters took advantage of the language and cultural references of the target demographic to drive a set of topics into public discourse and, further, to political activism. This discourse utilized a combination of affective modes, based mainly on resentment and schadenfreude, that we see echoing in many places on the internet. In the end, we argue that while #GG may have been only one instance of a campaign with harassment elements, the sentiments it cultivated and amplified as well as its operational logics have since been successfully employed in many similar online movements, including the current political campaigning associated with the so-called alt-right.fi=vertaisarvioitu|en=peerReviewed

    The development of the Turkish Craving for Internet Gaming Scale (CIGS): a validation study

    Get PDF
    As the use of digital technology has increased, abuse and addiction to technology have been identified among a minority of users. In the mid-1990s, the concept of internet addiction was first used. Today, almost every digital technology use has been claimed to have a minority of disordered users. One key aspect of addictive substance behaviors is craving. Craving is also an important component of behavioral addictions including digital technology disorders such as Internet Gaming Disorder. The aim of the present study was to develop the Turkish version of the Craving for Internet Gaming Scale (CIGS) via an adaptation of the Penn Alcohol Craving Scale (PACS). The present study comprised 368 adolescents from four different samples. The measures used included the Craving for Internet Gaming Scale, Digital Game Addiction Scale, and Brief Self-Control Scale. The structural validity of CIGS was investigated with Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and criterion validity. The reliability of CIGS was evaluated using Cronbach α internal consistency reliability coefficient and corrected item total correlation coefficients. As a result of EFA, it was found that the five-item CIGS had a single-factor structure. The unidimensional CIGS obtained as a result of EFA was tested with CFA. As a result of CFA, the unidimensional structure of CIGS was confirmed in two different samples. Criterion validity of CIGS was assessed via digital gaming addiction, self-discipline, impulsiveness, daily internet gaming duration, and internet gaming history. As a result of criterion analysis, CIGS was associated with these variables in the expected direction. Finally, according to reliability analysis, the CIGS was found to be a reliable scale. When validity and reliability analysis of the CIGS are considered as a whole, it is concluded that the CIGS is a valid and reliable scale that assesses craving for internet gaming

    The effects of hydergine on the MAO activity of the aged and adult rat brain

    No full text
    WOS: A1995TL31100014PubMed ID: 8998407Despite the fact that hydergine has been used in the treatment of dementia for many years, its mechanism of action is still not clear. Current studies imply that the major effect of hydergine may be the modulation of synaptic neurotransmission rather than solely increasing blood flow as was once thought. A prominent feature that accompanies aging is an increase in monoamine oxidase (MAO) levels which results in decreased availability of catecholamines in the synaptic cleft. The aim of this study was to determine the effects of hydergine on the MAO activity in different brain regions (cortex, olfactory bulb, hypothalamus, hippocampus, striatum, cerebellum) of old (30 months) and adult (12 months) male Sprague-Dawley rats. In cortex and olfactory bulb MAO levels were higher in the aged group. In hippocampus and hypothalamus hydergine treatment caused significant decreases in MAO levels. An interaction between age and hydergine treatment was observed in the hypothalamus, hippocampus and cerebellum. The hydergine effect was more pronounced in the aged group in the hypothalamus and cerebellum, and more pronounced in the adult in the hippocampus. Our findings imply that increased brain MAO activity in aging can be modified by hydergine treatment in some brain regions
    corecore