Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture.

Multi-fluid dynamics simulations require appropriate numerical treatments based on the main flow characteristics, such as flow speed, turbulence, thermodynamic state, and time and length scales. In this thesis, two distinct problems are investigated: supersonic jet and crossflow interactions; and liquid plug propagation and rupture in an airway. Gaseous non-reactive ethylene jet and air crossflow simulation represents essential physics for fuel injection in SCRAMJET engines. The regime is highly unsteady, involving shocks, turbulent mixing, and large-scale vortical structures. An eddy-viscosity-based multi-scale turbulence model is proposed to resolve turbulent structures consistent with grid resolution and turbulence length scales. Predictions of the time-averaged fuel concentration from the multi-scale model are improved over Reynolds-averaged Navier-Stokes models originally derived from stationary flow. The response to the multi-scale model alone is, however, limited, in cases where the vortical structures are small and scattered thus requiring prohibitively expensive grids in order to resolve the flow field accurately. Statistical information related to turbulent fluctuations is utilized to estimate an effective turbulent Schmidt number, which is shown to be highly varying in space. Accordingly, an adaptive turbulent Schmidt number approach is proposed, by allowing the resolved field to adaptively influence the value of turbulent Schmidt number in the multi-scale turbulence model. The proposed model estimates a time-averaged turbulent Schmidt number adapted to the computed flow field, instead of the constant value common to the eddy-viscosity-based Navier-Stokes models. This approach is assessed using a grid-refinement study for the normal injection case, and tested with 30 degree injection, showing improved results over the constant turbulent Schmidt model both in mean and variance of fuel concentration predictions. For the incompressible liquid plug propagation and rupture study, numerical simulations are conducted using an Eulerian-Lagrangian approach with a continuous-interface method. A reconstruction scheme is developed to allow topological changes during plug rupture by altering the connectivity information of the interface mesh. Rupture time is shown to be delayed as the initial precursor film thickness increases. During the plug rupture process, a sudden increase of mechanical stresses on the tube wall is recorded, which can cause tissue damage.Ph.D.Aerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91550/1/ezadel_1.pd

Trekanten is not square : shaping a new meeting site at the parking lot Trekanten

En stads centrum är dit du går för att möta andra människor, bli överraskad, få nya intryck, föreviga ögonblick och skapa nya ögonblick. Luleås centrum dör ut under kvällstid, delvis eftersom den största attraktionen är detaljhandeln. Denna uppsats ger förslag på hur Luleå kommun kan tillgodose sina invånares önskan att få en central mötesplats i staden. Förslaget är att ge parkeringsplatsen Trekanten i Luleå centrum en ny funktion som mötesplats. Uppsatsen börjar med att ta undersöka vad en mötesplats är och vad som är de grundläggande förutsättningarna för att en mötesplats ska uppstå. Sedan redovisar den reultatet på en enkät ställd till Luleås invånare samt platsanalyser gjorda på Trekanten. Efter det presenteras själva förslaget som bygger på att möta, koppla och aktivera. Det föreslås att Trekanten ska bli en aktivitetspark som uppmuntrar till möten, ger det intilliggande Kulturens Hus plats på Trekanten samt förbinder stadens gågata med den populära Norra Hamn. En avslutande diskussion tar bland annat upp den egna processen, enkäten som arbetsverktyg, det externa köpcentrumet kontra stadskärnan, bilens nödvändighet, att gestalta efter klimatet samt förslag på forstatt arbete inom området.The city center is where you go to meet other people, to be surprised, get new impressions, eternalize moments and create new moments. Luleå city center is a center that fades out in the evenings partly because the main attraction is retail. This essay suggests how Luleå municipality can meet its residents desire to have a central meeting place in the city by giving the parking lot Trekanten in Luleå city center a new function as a meeting site. The essay begins to examine what a meeting place is and what the fundamental conditions are for a meeting place to occur. Then the reultat on a questionnaire addressed to Luleå’s residents is presented together with ite analyzes made on Trekanten. After that a proposal is shown which is based on Trekanten to be an activity park that gives the adjacent Kulturens Hus a better anchorage in the surrounding area and connects the city’s pedestrian street with the popular North Harbour. A final discussion addresses the writers own process, the questionnaire as a research tool, the external shoppingcenter versus city center, car necessity, design in regard to climate and suggestions for further work in the field

With the human being in light

Kvällens och nattens miljöer formas av ljussättningen i densamma. Kunskap om hur människan påverkas av ljussättningen i våra miljöer, är en viktig del för skapandet av tillfredsställande platser under kvällstid. Den här uppsatsen ämnar ta upp en grundläggande bas, från människans perspektiv, att stå på inom ämnet ljusdesign inför en framtida fördjupning inom ämnet. Uppsatsen undersöker forskning och litteratur om ljuset och ljusfärgers indirekta påverkan på komfort och välmående. Den tar upp en metod för utvärdering och läsning av ljus, för skapande av personliga preferenser och kunskaper om hur ljussatta miljöer kan te sig. Utvärderingsmetoden tillämpas även på Möllevångstorget i Malmö. Intervjuer har gjorts med yrkesverksamma inom ljusdesign, med avsikt att undersöka hur det resoneras kring de mänskliga faktorerna i planeringen av utemiljöer idag. En diskussion avslutar uppsatsen där forskning, litteratur och intervjuer vävs samman med författarens egna reflektioner.The evening and nights environments are shaped by the lighting of the same. Knowledge about how humans are affected by the lighting in our environments is an important component in the creation of satisfactory places in the evening. This essay intends to raise a fundamental base, from the human perspective, to lean against in the subject of lighting design prior to further studies in the subject. The essay examines literature and research on light and lightcolors indirect impact on comfort and well being. It brings up a method for evaluating and reading light, for the creation of personal preferences and knowledge on how lit environments can appear. The method is also applied on Möllevångstorget in Malmö. Interviews have been made with professionals in lighting design, with intent to examine how they reason regarding human factors in planning of outdoor environments today. A discussion concludes the essay where research, literature and interviews are interwoven with the author’s own reflections

The therapeutic benefit of ALPPS technique for classically described marginal irresectable intrahepatic cholangiocarcinoma tumors: a propensity score analysis

Introduction: Despite of its encouraging primary results, “Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy” ALPPS procedure remains highly controversial. At present, the mid and long-term outcome of ALPPS procedures performed for Intrahepatic Cholangiocarcinoma (IC) patients remain unverified. Aim of Work To evaluate the long-term therapeutic benefit of ALPPS procedure for Intrahepatic cholangiocarcinoma in terms of oncological outcome and overall survival, in comparison to palliative chemotherapy with special emphasis on morbidity and early mortality. Patients and Methods: This is a longitudinal cohort multicenter study with prospective evaluation of long-term outcome of ALPPS procedure for IC patients in comparison to a propensity scored matched patients received palliative chemotherapy (CTH). Results: For ALPPS group (n=79), the median overall survival (OS) was 27.6 months. The 1,2,3-year survival rates were 68,1%, 60.1% and 40.8%. For propensity score matched group of CTH patients (n=79), the median OS was 12 months. The 1,2,3-year survival rates were 49,7%, 18.4% and 9.2%. (p value < 0.004). By multivariate COX regression analysis poor prognosis has been reported for cases developing infection post 2nd stage hepatectomy (p=0.03, HR=2.1, CI= 95%) and/or positive lymph node metastasis(p=0.007, HR=2.7, CI95%). During the study period, 90-day mortality rate was reported in 19% of the cases. According Dindo-Clavien classification of postoperative complications; 34.5% had score ≥ 3b (n=28/81). Sever infection classified as Dindo-Clavien grade IIIb was reported in 9% (n=7/77). According to ISLGS; biliary leakage reported in 9 % of the patients which is classified as grade C and 13.4 % of the patients (n=9/67) have developed PHLF classified as grade C. Conclusion: Despite of its relatively high morbidity and early mortality; ALPPS approach shows remarkable superior results in overall survival analysis compared to palliative chemotherapy for Intrahepatic cholangiocarcinoma patients. More strict risk adjustments are mandatory to avoid post-operative morbidity and mortality. Further studies are needed to identify the subgroup of IC patients who would potentially benefit from the procedure with acceptable morbidities and negligible early postoperative mortalit

Multi-Scale Turbulence Model in Simulation of Supersonic Crossflow

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90706/1/AIAA-2011-478-317.pd

NDM-559: EXPERIMENTAL INVESTIGATION OF TWO-WAY CONCRETE PANELS EXPOSED TO IMPACT LOAD

Protecting existing and new structures from potential terrorist attacks and accidents is becoming an essential consideration in the design of most structures. Building façade is the first layer exposed to external loading, thus it acts as the first line of defence against external loads. Precast concrete panels are mostly used in external building\u27s façade for modern construction, and therefore their resistance to other dynamic loads such as impact load needs further evaluation. This paper presents the results of an experimental research on two-way reinforced concrete panels as well as thin ferrocement concrete panels under impact loading. The impact test apparatus used is versatile enough to test large variety of specimens modeling façade units. The performance of the panels under impact load is evaluated in terms of: the failure mode; the maximum impact loads sustained by the panels; the number of impact loads up to failure; the maximum load transmitted to the supporting frame; and the strain induced in the panels. The effect of the different design parameters including the reinforcement amount, spacing and location across the panel thickness on the dynamic response of the panel to impact load are considered. Results clearly showed the significant effect of reinforcement on the overall resistance to impact loading. This research outcomes provide a better understanding of the performance of concrete panels under impact loading that can help enhancing structural design under such loads

Modelling the influence of age of steel fibre reinforced self-compacting concrete on its compressive behaviour

Steel fibre reinforced self-compacting concrete (SFRSCC) can combine the benefits of self-consolidating concrete technology with those derived from adding steel fibres to quasi-brittle cement based materials. In a recent applied research project joining pre-casting industry, private and public research institutions, a method was developed to design cost-competitive SFRSCC of rheological and mechanical properties required for the prefabrication of SFRSCC fac¸ade panels. To assure safe demoulding process of the panels, the influence of the concrete age on the compression behaviour of the SFRSCC should be known. For this purpose, series of tests with specimens of 12 h to 28 days were tested in order to analyze the age influence on the compressive strength, strain at peak stress, Young’s modulus, and compressive volumetric fracture energy. The experimental program was divided in two groups of test series, one with SFRSCC of a volumetric fibre percentage of 0.38% and the other with 0.57%. To apply the obtained data in the design and numerical analysis framework, the influence of the age on these SFRSCC properties was modelled. This work describes the carried out experimental program, presents and analyzes the obtained results, and provides the derived analytical expressions

Drive-up INR testing and phone-based consultations service during COVID-19 pandemic in a pharmacist-lead anticoagulation clinic in Qatar: Monitoring, clinical, resource utilization, and patient- oriented outcomes

Background: Coronavirus disease 2019 (COVID-19) pandemic has resulted in unprecedented pressure on healthcare systems and led to widespread utilization of telemedicine or telehealth services. Combined with teleclinics, using drive-up fingerstick International normalized ratio (INR) testing was recommended to decrease exposure risk of anticoagulation patients. Objective: To evaluate the impact of transitioning from clinic-based anticoagulation management services to drive-up and phone-based services during COVID-19 pandemic in Qatar. Methods: The study comprised of two components: a retrospective cohort study of all eligible patients who attended anticoagulation clinic over 1-year period (6 months before and 6 months after service transition) and a cross-sectional survey of eligible patients who agreed to provide data about their satisfaction with the new service. Monitoring parameters, clinical outcomes, and resource utilization related to warfarin therapy were compared before and after service transition. Patients' experience was explored through a structured survey. Results: There was no statistically significant difference between clinic-based and phone-based anticoagulation services in mean time and number of visits within therapeutic range (P =.67; P =.06 respectively); mean number of extreme subtherapeutic and supratherapeutic INR values (P =.32 and P =.34, respectively); incidence of thromboembolic complications and warfarin related hospitalization. There was one reported bleeding and one emergency visit (0.9%) in the phone-based group vs none in the clinic-based group. Frequency of INR testing and compliance to attending clinics appointments declined significantly (P =.002; P =.001, respectively). Overall, patients were highly satisfied with the new service. The majority of patients found it better (51.6%) or just as good as the traditional service (44.5%). Patients who preferred the new service were significantly younger than their counterparts (P =.005). Conclusion: The service of drive-up INR testing and phone-based consultations was shown to be comparable to traditional anticoagulation service, a finding that supports maintaining such services as part of the new normal after the pandemic is over

Large volume, high-performance applications of fibers in civil engineering

This article presents an overview of fiber applications in cementitious composites. The socio-economic considerations surrounding materials development in civil engineering in general, and fiber reinforced cementitious materials in particular, are described. Current FRC appliations are summarized, and the where, how, and why fibers are used in these applications, are documented. An attempt is made to extract common denominators among the widely varied applications. The R&D and industrial trends of applying fibers in enhancing structural performance are depicted. An actual case study involving a tunnel lining constructed in Japan is given to illustrate how a newly proposed structural design guideline takes into account the load carrying contribution of fibers. Composite properties related to structural performance are described for a number of FRCs targeted for use in load carrying structural members. Structural applications of FRCs are currently under rapid development. In coming years, it is envisioned that the ultra-high performance FRC, with ductility matching that of metals, will be commercially exploited in various applications. Highlights of such a material are presented in this article. Finally, conclusions on market trends are drawn, and favorable fiber characteristics for structural applications are provided. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 660–686, 2002Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34401/1/2263_ftp.pd