Precast Concrete Deck-to-Girder Connection using UHPC

The implementation of ultra-high-performance concrete (UHPC) in bridge construction has been growing rapidly in the last two decades due to its excellent mechanical properties, workability, and durability. This report presents a new UHPC connection between precast concrete deck panels and bridge girders that eliminates changes to the design and production of girder shear connectors commonly used in conventional cast-in-place concrete deck construction. In conventional construction, girder shear reinforcement or studs are extended into the cast-in-place concrete deck to transfer interface shear and create composite section. In the new connection, girder shear reinforcement or studs are kept underneath the deck panels, while UHPC is used instead to fill the haunch and shear pockets and transfer interface shear between deck panels and girders. Using UHPC and eliminating changes to standard shear connectors make precast concrete deck systems more economical and enhance their constructability. The report presents the experimental investigation conducted to evaluate the interface shear resistance of UHPC using direct shear, slant shear, L-shape push-off, and double shear tests. Also, three full-scale specimens of the new connection were constructed and tested to evaluate its structural performance and constructability. Based on the experimental investigation results, empirical equations were developed to predict the interface shear resistance of the new connection and develop design aids for different bridge types and configurations. Design procedures and construction recommendations were also developed based on the outcomes of the experimental investigation

A Process for Producing Ice Coverage Marine Information Objects (MIOs) in IHO S-57 Format

While global warming may be opening up more Arctic waters in the summer, ice still infests key shipping lanes in the northern hemisphere during the winter months. To safely navigate these areas, mariners rely on daily ice coverage charts produced by national governmental agencies. Ice charts are primarily issued in paper format or as a fax. However, there is increased interest to ice coverage information on vessel navigation systems such as an Electronic Chart and Display Information Systems (ECDIS). However, to do so, the ice information must be provided as a separate layer of information to the Electronic Navigational Chart (ENC)

Changes in Technical Services and Their Effect on the Role of Catalogers and Staff Education: An Overview

Summary: Though all library operations are affected by the development of technology, technical services operations are the first to undergo massive organizational restructuring in response. Some current changes and their effects on library cataloging departments are addressed. Two cataloging options are discussed. One is the use of vendor services, such as OCLC's Contract Cataloging, Prompt-Cat, and OCLC Selection. The other is the use of non-traditional staff. The impact of such changes on the role of librarians and on staff education is considered

Breaking the Buildup-time Limit of sensitivity in Avalanche Photodiodes by Dynamic Biasing

Avalanche photodiodes (APDs) are the preferred photodetectors for direct-detection, high data-rate long-haul optical telecommunications. APDs can detect low-level optical signals due to their internal amplification of the photon-generated electrical current, which is attributable to the avalanche of electron and hole impact ionizations. Despite recent advances in APDs aimed at reducing the average avalanche-buildup time, which causes intersymbol interference and compromises receiver sensitivity at high data rates, operable speeds of commercially available APDs have been limited to 10Gbps. We report the first demonstration of a dynamically biased APD that breaks the traditional sensitivity-versus-speed limit by employing a data-synchronous sinusoidal reverse-bias that drastically suppresses the average avalanche-buildup time. Compared with traditional DC biasing, the sensitivity of germanium APDs at 3Gbps is improved by 4.3 dB, which is equivalent to a 3,500-fold reduction in the bit-error rate. The method is APD-type agnostic and it promises to enable operation at rates of 25Gbps and beyond

Metadata and Cataloging Practices

Metadata standards existing today range from very complex to very simple. Relative simplicity or complexity of metadata standards depends in large part on the resources for which they were created and the depth of description that is deemed necessary to make these resources accessible. This paper reviews the differences between metadata standards and current cataloging practices, and discusses how the various metadata standards are applied in libraries. In addressing these issues, the authors introduce definitions of key concepts of metadata and cataloging standards and provide an overview of the most common metadata schemes. The discussion of current cataloging practices includes an overview of the most commonly used cataloging practices and standards, the impact of metadata on library practice and the role of librarians related to metadata. The authors will discuss the OHIOLINK Electronic Thesis and Dissertations (ETD) as an example of how Anglo-American Cataloging Rules 2nd (AACR2) and Machine Readable Cataloging (MARC21) are used as metadata to store, describe and access this unique information resource

The Effect of Laboratory Experiments on the Upper Basic Stage Students Achievement in physics.

This study investigates the effect of laboratory experiments on grade ten students’ achievement in physics. It answers the question: Is there any effect on the tenth grade students( male and females discretely ) achievement that can be attributed to laboratory experiment? The sample of the study consisted of 130 Jordanian students. The experimental group students were taught physics in conjunction with  laboratory experiments for forty five days.  A thirty multiple choice item achievement test was designed to measure the students achievement .The study showed that the experimental group students achievement was higher than that of the control group students. The researcher recommends that(1) it is necessary to use the laboratory experiments in teaching science ,in general, and physics in particular, (2) the teaching schedule should include weekly classes for laboratory experiments in science, because this greatly enhances the student achievement in such topics .(3) Further similar studies involving  different school stages and science branches like biology, chemistry and geology should be carried out. Key words: lab experiments , students achievement . science , physics , science teachin

Towards a model and strategy for transformational change

Leaders must ask critical questions when deciding to initiate change such as: Where to begin? What and how to organize resources? How to distribute responsibilities within the organization? These questions are especially important when an organization faces the need to change in the instance of a crisis. Leaders must develop objectives, which accomplish strategic goals. Logically, these goals categorize into explicit actions: the organization should clarify how they sequence and correlate a change strategy.  Articulating precisely which capacities, structures, and product offerings influence how stakeholders perceive change within organizations is vital. This article sketches key processes and pathways that make transformational change possible

The histone chaperones Nap1 and Vps75 bind histones H3 and H4 in a tetrameric conformation

Histone chaperones physically interact with histones to direct proper assembly and disassembly of nucleosomes regulating diverse nuclear processes such as DNA replication, promoter remodeling, transcription elongation, DNA damage, and histone variant exchange. Currently, the best-characterized chaperone-histone interaction is that between the ubiquitous chaperone Asf1 and a dimer of H3 and H4. Nucleosome assembly proteins (Nap proteins) represent a distinct class of histone chaperone. Using pulsed electron double resonance (PELDOR) measurements and protein crosslinking, we show that two members of this class, Nap1 and Vps75, bind histones in the tetrameric conformation also observed when they are sequestered within the nucleosome. Furthermore, H3 and H4 trapped in their tetrameric state can be used as substrates in nucleosome assembly and chaperone-mediated lysine acetylation. This alternate mode of histone interaction provides a potential means of maintaining the integrity of the histone tetramer during cycles of nucleosome reassembly