Timber joinery in modern construction: Mechanical behavior of wood-wood connections

Thesis: S.M. in Building Technology, Massachusetts Institute of Technology, Department of Architecture, May, 2020Cataloged from the official PDF of thesis.Includes bibliographical references (pages [107]-112).Timber joinery is a method of geometrically interlocking timber elements prevalent in historic cultures around the world, including North America, Europe, and East Asia. The use of joinery as structural connections faded with the development of metallic screws and nails. Two recent developments offer the opportunity to revive this historic timber connection type: 1) the increasing desire to reduce embodied carbon in buildings by replacing more components with timber as a low-carbon structural material, and 2) recent digital fabrication capabilities which enable the precise milling of complex geometries as an alternative to the time- and labor-intensive handiwork required previously. How can joinery connections be designed in modern structural joints? Can we quantify the sustainability advantage of using these all-timber joints in lieu of the modern convention of metallic fasteners? This thesis addresses both questions as applied to the Japanese Nuki joinery type, though the workflows may be applied to any joinery geometry. First, the rotational stiffness of the Nuki joint is characterized and cross-verified using multiple methods. Second, the embodied carbon of a gravity frame using Nuki joints is compared to that of a gravity frame using conventional metallic fasteners. The use of Nuki joints not only eliminates the use of steel and aluminum but also provides rotational stiffnesses that enable smaller beam sections to be used. It is shown that gravity frames designed with Nuki joints could reduce embodied carbon by over 70% compared to gravity frames designed using conventional beam hanger connections. The findings make a case for all-timber joinery connections to be implemented as a sustainable alternative to conventional metallic connections used in modern timber construction.by Demi L. Fang.S.M. in Building TechnologyS.M.inBuildingTechnology Massachusetts Institute of Technology, Department of Architectur

Long-term Care in Turmoil

The reformulation of the regulation of long-term care seen in the recent White Paper and Royal Commission in the UK has led to topical debates on long-term care for older people. Given that there are over 500,000 people in residential nursing and dual registered homes across the country, there has, until now, been remarkably little research on the role of managers in the long-term care sector, the various tasks they undertake in the day-to-day operation of a care home, and the qualities and qualifications they bring to their work. This study investigates the range of tasks which managers of long-term care homes perform, and the skills they should possess to do their work. The opening chapter reproduced here provides a critical analysis of the current confusion which besets UK policy on long term care.long-term care; aging

The Kinetics Of Influenza A (A/CALIFORNIA/4/2009-H1N1) And B (B/PHUKET/3073/2013 (BYAM), B/BRISBANE/60/2008 (BVIC)) Virus Infection In Ferrets

Influenza is a persistent threat to individual and global health. Seasonal influenza kills nearly 500,000 people globally each year. Influenza viruses have circulated within the human population, causing a significant disease burden. In order to create the most effective antiviral therapies, knowledge concerning all lineages of influenza must be studied accurately and thoroughly. The influenza virus itself is not always responsible for these mortalities, rather, the secondary bacterial infections associated with death. In order to protect the population and examine the secondary infections that arise, the kinetics of influenza must be studied entirely. To understand the kinetics, researchers are turning to the use of laboratory experimentation using ferrets as an effective model. This is done through the use of common laboratory procedures such as TCID50’s and hemagglutination assays. Through the use of these procedures, the kinetics of influenza A and B can be confirmed. Within this study, it was confirmed that influenza A infects both the upper and lower respiratory system, while influenza B infects the upper respiratory tract but fails to reach the lower lungs. Understanding the kinetics of influenza is the first step toward creating effective therapies to reduce the mortality and illness associated with the influenza virus infection

Entrance of medium sized companies in PPP projects in Greece

A number of PPP projects have been announced recently in Greece introducing a new procurement method in the projects covering public needs. The aim of the present report is to present the strategy adopted by the majority of medium sized companies foreseeing in bidding such projects. The risks and the uncertainty of the PPPs led the firms to hesitate on participating on alone bidders and strategic alliances came as the solution. Moreover, the absence of knowledge on past infrastructure projects under the umbrella of PPPs was a subject of significant importance. Therefore, the strategy should be used as the mean to surpass the unfamiliarity with the PPPs while the rest of the bidders have already had experience. The partners in the strategic alliances were chosen carefully by the participating firms with the main characteristic being the repeated ties between them. So, they introduced the implementation of trust as their mean to overcome the barriers for entry in the field of the PPPs. Relational contracting is the concept that the firms used as their criterion for choosing partners. Key words: PPPs, medium sized companies, strategic alliances, relational contracting, trust Word

Observed cumulative time delay between second harmonic and fundamental component of pressure wave fields propagating through ultrasound contrast agentss

Several studies on the propagation velocity of pressure wave fields through ultrasound contrast agents (UCAs) have been reported in the literature. However, the variation of propagation velocity between the fundamental and the second harmonic component generated during the propagation of ultrasound through UCAs has, to our knowledge, not been studied yet. To this scope, dedicated transmission and backscattering measurements of pressure wave fields propagating through SonoVue and Definity contrast agents, are analyzed. Results show the occurrence of a cumulative delay between the time signals related to the second harmonic and fundamental component, suggesting a smaller propagation velocity for the second harmonic as compared to the fundamental component. Moreover, this time delay increases with increasing UCA concentration and propagation path length of ultrasound trough microbubbles, depends on mechanical index and frequency, and, most importantly, is not observed in the absence of UCAs. These results may be relevant to contrast-enhanced ultrasonography, opening up to new possibilities to increase contrast-to-tissue ratios and to quantify UCA concentration

Towards dynamic contrast specific ultrasound tomography

We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast.</p

Ultrasound transducer positioning aid for fetal heart rate monitoring

Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily

The atypical chemokine receptor Ackr2 constrains NK cell migratory activity and promotes metastasis

Chemokines have been shown to be essential players in a range of cancer contexts. In this study, we demonstrate that mice deficient in the atypical chemokine receptor Ackr2 display impaired development of metastasis in vivo in both cell line and spontaneous models. Further analysis reveals that this relates to increased expression of the chemokine receptor CCR2, specifically by KLRG1+ NK cells from the Ackr2−/− mice. This leads to increased recruitment of KLRG1+ NK cells to CCL2-expressing tumors and enhanced tumor killing. Together, these data indicate that Ackr2 limits the expression of CCR2 on NK cells and restricts their tumoricidal activity. Our data have important implications for our understanding of the roles for chemokines in the metastatic process and highlight Ackr2 and CCR2 as potentially manipulable therapeutic targets in metastasis