The nonlinear analysis of an innovative slit reinforced concrete water tower in seismic regions

Water towers are widely used in our society as one of water distribution facilities within water network systems. In the event of a severe earthquake, however, a single plastic hinge that occurs in a water tower could cause its total collapse before nonlinear resources of the rest of the tower remains fully utilised. This research presents an innovative technique for the assembly of a water tower using the slits in its reinforced concrete shaft for the purpose of mitigating the seismic response. Slit shafts were designed to have four slits at 90 degree intervals along the full height of the shafts. The shaft parts were connected to each other at the bottom, top and every five meters with coupling beams. The slit width was used as a variable in this study which varied between 50 mm and 2000 mm. The nonlinear seismic performance of the proposed slit towers was analysed by means of a finite element approach with respect to soil types defined in Eurocode 8 and seismic behaviour were compared to the solid water tower. A detailed observation of the compression and tension stress distributions with respect to the slit width was performed. The obtained analytical results revealed that slit width in the reinforced concrete tower affect the failure mode and stiffness of a water tower significantly. With an appropriate design, the conversion of a solid water tower into a slit tower can significantly increase its ductility under seismic action without significantly compromising its bearing capacity. The results showed that contours of tension and compression stress intensity in shafts, which could lead to a failure of water towers, highly depended on the slit width. In the solid water tower, the stress concentration dominated at the base of the shaft, however in the narrow slit water towers the stresses were equally distributed along the height of the shafts. Also, the stresses were mostly concentrated at the top of the shafts in the wide slit water towers. Conclusively, the results provided useful information regarding the compression stress distribution along the slit shafts in the water towers which can be used in obtaining an optimum slit shaft design for different soil types

Sambandet mellan våld mot djur och våld i nära relationer

Våld i nära relationer är ett allvarligt samhällsproblem och ofta förekommer våld mot husdjur parallellt med den sortens våld. Denna överlappning mellan våld mot djur och våld i nära relationer har utretts, vilket har resulterat i att ett samband har synliggjorts och fastställts. Studien ämnar undersöka och beskriva djurhälsoperso-nalens roll i bemötandet av såväl djurs som människors utsatthet i våldsrelationer. För att undersöka och beskriva det påvisade sambandet och djurhälsopersonalens roll sammanställdes litteratur från tidigare forskning i ämnet. Det gjordes även tre djupintervjuer med informanter från olika grenar inom djursjukvård och arbetet med våldsutsatta i Sverige. Resultatet av litteraturstudien visade att sambandet mellan våld mot djur och våld i nära relationer samt igenkännandet av våldsutsatta djur har fått större plats inom forskningen de senaste två årtiondena. Det framkom att endast en begränsad an-del forskning som utforskar detta fenomen var från Sverige. Flertalet studier påta-lar hur personal inom djursjukvården kan medverka vid upptäckten av våldsutsatta djur och därigenom våldsutsatta människor. Från internationell forskning framkom ett resultat där djurhälsopersonal ansågs sakna den kunskap som krävs för att inta en nyckelroll i arbetet med våldsutsatta. Att inte acceptera det faktum att våldet är utbrett bidrar till att den verkliga orsaken till skadorna hos våldsut-satta djur förbises. Stress, rädsla för det egna ryktet och okunskap är faktorer som bidrar till att djurhälsopersonal verkar motvilliga till att rapportera och anmäla misstanken om våld mot djur. Genom intervjustudien framkom ett liknande förhållningssätt till fenomenet i Sve-rige gällande vilka utmaningar som försvårar arbetet med våldsutsatta. Det fram-kom att den största utmaningen anses vara bristen på kunskap i ämnet. Det fram-kom dock att djurhälsopersonal anses ha en central roll i bemötandet av såväl utsatta djur som människor och att det finns aktörer som arbetar för att utbilda och ta fram nödvändigt material som ämnar att underlätta för djurhälsopersonal vid hantering av fall av detta slag. Synen på djurhälsopersonalens ansvar skiljer sig i vad det grundar sig i. Ansvaret för djuren anses vara en skyldighet som tillhör yrket, medan ansvaret för den utsatta människan bör komma från medmänsklighet. Att universitetsutbildningar inom djuromvårdnad och veterinärmedicin behöver lägga större vikt vid utbildning av studenter inom ämnet våldsutsatta djur, sam-bandet mellan våld mot djur och våld i nära relationer, våldets mekanismer och att identifiera våldsrelaterade skador, är resultatet utifrån den här studien. Utifrån analysen framkom även att det finns ett visst behov av ett ökat engagemang gäl-lande arbetet med våldsutsatta hos kliniskt verksam djurhälsopersonal, så att de i högre utsträckning ska kunna fullfölja deras yrkesmässiga ansvar för god djurvälfärd

Nonlinear seismic response of reinforced concrete pedestals in elevated water tanks

Elevated water tanks are employed in water distribution facilities in order to provide storage and necessary pressure in water network systems. These structures have demonstrated poor seismic performance in the past earthquakes. In this study, a finite element method is employed for investigating the nonlinear seismic response of reinforced concrete (RC) pedestal in elevated water tanks. A combination of the most commonly constructed tank sizes and pedestal heights in industry are developed and investigated. Pushover analysis is performed in order to construct the pushover curves, establish the overstrength and ductility factor, and evaluate the effect of various parameters such as fundamental period and tank size on the seismic response factors of elevated water tanks. Furthermore, a probabilistic method is implemented to verify the seismic performance and response modification factor of elevated water tanks. The effect of wall openings in the seismic response characteristics of elevated water tanks is investigated as well. Finally, the effect of axial compression on shear strength of RC pedestals is evaluated and compared to nominal shear strength from current guideline and standards. The results of the study show that the tank size, pedestal height, fundamental period, and pedestal height to diameter ratio, could significantly affect the overstrength and ductility factor of RC pedestals. The nonlinear dynamic analysis results reveal that under the maximum considered earthquake (MCE) intensity, light and medium size tank models do not experience significant damages. However, heavy tank size models experience more damage in comparison with light and medium tank sizes. This study shows that the current code response modification factor values are appropriate for light and medium tank sizes; however they need to be modified for heavy tank sizes. The results of this study also reveal that if the pedestal wall openings are designed based on current design guidelines, then nearly identical nonlinear seismic response behaviour is expected from the pedestals with and without openings. Finally, it is shown that the pedestal maximum shear strength calculated by finite element method for the full tank state is higher than the nominal shear strength determined based on the current design guidelines compared to the nominal shear strength from current guideline and standards.</jats:p

Nonlinear seismic response of reinforced concrete pedestals in elevated water tanks

Elevated water tanks are employed in water distribution facilities in order to provide storage and necessary pressure in water network systems. These structures have demonstrated poor seismic performance in the past earthquakes. In this study, a finite element method is employed for investigating the nonlinear seismic response of reinforced concrete (RC) pedestal in elevated water tanks. A combination of the most commonly constructed tank sizes and pedestal heights in industry are developed and investigated. Pushover analysis is performed in order to construct the pushover curves, establish the overstrength and ductility factor, and evaluate the effect of various parameters such as fundamental period and tank size on the seismic response factors of elevated water tanks. Furthermore, a probabilistic method is implemented to verify the seismic performance and response modification factor of elevated water tanks. The effect of wall openings in the seismic response characteristics of elevated water tanks is investigated as well. Finally, the effect of axial compression on shear strength of RC pedestals is evaluated and compared to nominal shear strength from current guideline and standards. The results of the study show that the tank size, pedestal height, fundamental period, and pedestal height to diameter ratio, could significantly affect the overstrength and ductility factor of RC pedestals. The nonlinear dynamic analysis results reveal that under the maximum considered earthquake (MCE) intensity, light and medium size tank models do not experience significant damages. However, heavy tank size models experience more damage in comparison with light and medium tank sizes. This study shows that the current code response modification factor values are appropriate for light and medium tank sizes; however they need to be modified for heavy tank sizes. The results of this study also reveal that if the pedestal wall openings are designed based on current design guidelines, then nearly identical nonlinear seismic response behaviour is expected from the pedestals with and without openings. Finally, it is shown that the pedestal maximum shear strength calculated by finite element method for the full tank state is higher than the nominal shear strength determined based on the current design guidelines compared to the nominal shear strength from current guideline and standards.</jats:p

The impact of the digital tool Zoom on students’ motivation and engagement : Focusing on students from the faculty of Technology and Society at Malmo university.

Till följd av Covid-19 pandemin som bröt ut fick Malmö Universitet i mars 2020 förflytta merparten av utbildningar till att genomföras digitalt över Zoom. Universitetet, lärarna och studenterna var snabbt tvungna att anpassa sig till den nya situationen utan vidare förberedelser. Zoom blev snabbt det videokonferensverktyg som flera universitet kom att använda sig av vid övergången till digitala studier, vilket även Malmö universitet valde att använda sig av. Syftet med denna studie var att undersöka om studenterna på Teknik och Samhälle upplevde att deras motivation och engagemang påverkats sedan den digitala övergången. Detta utforskades genom frågeställningen: ”Hur påverkar Zoom studenters motivation och engagemang vid digital undervisning?”. Studien undersökte huruvida det fanns en koppling mellan hur studenterna upplevde Zooms användarvänlighet och användbarhet, deras studiemotivation samt engagemang i form av deltagande. Metoderna som användes för studien var observationer samt en enkätundersökning.   Slutsatserna av studien var att studenterna ansåg att Zoom var användarvänligt men inte lika användbart och att studenternas motivation och engagemang hade påverkats negativt. Slutligen indikerade även slutsatsen på att studiemotivation hade ett samband med användarvänlighet, användbarhet och engagemang. Men engagemang hade dock endast ett samband med motivation och användarvänlighet.As a result of the Covid-19 pandemic Malmö University had to transfer most of their educations to be carried out digitally in March 2020. The university, teachers and students were quickly forced to adapt to the new situation without further preparation. Zoom quickly became the video conferencing tool that several universities came to use in the transition to digital studies, which Malmö University also chose to use. The purpose of this study was to investigate whether the students at the faculty of Technology and Society felt that their motivation and engagement had been affected since the digital transition. This was explored through the research question: “How is the motivation and engagement of students affected when attending lectures through the digital tool Zoom?”. The study examined how students experienced Zoom's perceived ease of use and perceived usefulness, their study motivation and finally their engagement in the form of participation. The methods used in the study were observations and a questionnaire survey. The conclusions of the study were that the students felt that Zoom was easy to use, but not as useful and that the students' motivation and engagement had been negatively affected. Finally, the conclusion also indicated that study motivation had a correlation with perceived ease of use, perceived usefulness and engagement. But engagement only had a correlation with perceived ease of use and motivation