Physical properties of concrete at early ages

The introduction of the motor vehicle and the subsequent rapid expansion of the highway systems of the United States have brought with them many problems. The Civil Engineer, in his attempts to provide adequate safe avenues of travel for the populace, has been faced with many problems. Handicapped by the need for speed in design and lack of information of the trends in motor vehicle design, the engineer has been forced at times to utilize design methods inconsistent with good engineering practices. Of the many types of pavement sections which have been designed in an effort to provide structurally and economically suitable transportation avenues, the rigid type portland cement section represents one of the best known and most durable in use today. Rigid and durable as they may be, these pavements are still cracking and breaking up under the action of traffic. Engineers in an effort to adapt this design to increasingly heavy axle loadings and higher traffic volumes and eliminate cracking and subsequent shortening of pavement life, have followed two separate design trends. One of these has been the use of short, un-reinforced slabs, whose action under load would be as a complete unit in the transference of stresses to the subgrade. Also, attempt has been made to thoroughly and completely compact the sub-grade so as to obviate any necessity for so-called bridging” and subsequent possibility of cracking. Still other designs have thought to handle heavier loadings by increasing the depth of paving section, thus lowering the sections flexibility, however, this procedure has increased the cost prohibitively. These attempts have failed to eliminate completely cracking, infiltration of moisture to the sub-grade, and the relatively short pavement life. Investigations have been, and are being conducted by various organizations throughout the United States in an effort to analyze pavement action under load, the effect of temperature change, and the possibility of developing new criteria for design. Effort is also being made to investigate the properties of the various materials used in highway construction so as to utilize them to better advantage. The last two mentioned items have led to this investigation. Development of pre-stressing procedures and technique and better understanding of this useful construction method has suggested its application to pavement design. If prestressing our highway slabs is to be practical, we must immediately consider the properties of the concrete to be used. Modern highway construction methods require continuity of action, no lost motion, no duplication of effort, and if we are to maintain the time sequence which has become standard we must understand the early age properties of the material we use. It is hoped that the result of this project and others of similar nature may be utilized for the development of better, safer, more durable highways for the use of future generations --Introduction, pages 1-2

Cell-format-dependent mechanical damage in silicon anodes

It is generally believed that silicon-based anodes for Li-ion batteries would benefit from stronger binders, as cyclic volume changes would not disrupt the cohesion of the composite electrode. Here, we put this belief to the proof by testing electrodes containing SiOx particles and an aromatic polyimide binder. We observe that the electrodes can stretch laterally by as much as 6% during the first cycle, indicating that internal stresses are high enough to induce plastic deformation on the copper current collector. Remarkably, no coating delamination is observed. Additional consequences were size-dependent: while pouch-cell-sized electrodes developed wrinkles, coin-cell-sized ones remained mostly smooth. We demonstrate that wrinkling of the current collector damages the electrode coating, inactivating SiOx domains and accelerating capacity fade. This size-dependent performance decay indicates that, in extreme cases, testing outcomes are highly dependent on scale. Novel battery materials may require testing at larger cell formats for complete validation

One size does not fit all: advanced practice provider considerations for the antimicrobial steward

Advanced practice providers are a diverse and established group of antimicrobial prescribers in both ambulatory and inpatient settings. We outline important considerations for antimicrobial stewardship programs and stewards to consider when engaging this important group of providers

An investigation into E-business service in the UK telecommunication manufacturing industry

Nowadays, suppliers’ product and service quality has risen in importance with a manufacturer’s push to develop core competencies and capitalise on global operations and markets. However, due to the complex features of business service, suppliers are facing significant challenges in providing service effectively and developing business collaboration. This is further complicated by the development of information and communication technologies (ICTs). This paper thus attempts to investigate the factors influencing buyers’ e-service (EBS) requirements and the impact of these requirements on business collaboration. Based on a questionnaire survey with 500 UK telecommunication manufacturers, this research identifies buyers’ different EBS requirements for different types of suppliers and the impact of ICTs on EBS requirements. While for suppliers our findings provide insights into buyers’ EBS requirements, they can help buyers to develop appropriate supplier selection criteria. The findings also contribute to a better understanding of the development of buyer and supplier business collaboration

HIV policy: the path forward--a joint position paper of the HIV Medicine Association of the Infectious Diseases Society of America and the American College of Physicians.

Executive Summary The American College of Physicians (ACP) and the Infectious Diseases Society of America (IDSA) have jointly published 3 policy statements on AIDS, the first in 1986 [1], the second in 1988 [2], and the third in 1994 [3]. In 2001, the IDSA created the HIV Medicine Association (HIVMA), and this updated policy paper is a collaboration between the ACP and the HIVMA of the IDSA. Since the last statement, many new developments call for the need to reexamine and update our policies relating to HIV infection. First, there have been major advances in treatment for HIV infection that have transformed HIV/AIDS from a terminal illness to a chronic disease for many of those who have access to potent therapies and expert medical care [4]. Second, there has been a profound expansion and intensification of the global HIV pandemic, particularly in sub-Saharan Africa, coupled with significant US leadership and resources aimed at providing prevention and care services to affected populations in developing countries. Third, the concerns that were prevalent in the mid-1990s regarding the possibility of HIV transmission in health care settings have ultimately proven to be unfounded as the result of the adoption of universal precautions in those settings. In this article, we emphasize the public health and clinical imperatives for earlier identification of persons with HIV infection; the urgent need to expand access to state-of-the-art HIV care and treatment for infected individuals; the need for access to comprehensive prevention and education for those living with and those at risk for HIV infection; and the need for stronger national leadership to respond to the HIV epidemic in the United States and in the developing world. In December 2008, the ACP and HIVMA released a guidance statement on screening for HIV infection in health care settings that recommended that clinicians adopt routine screening for HIV infection and encourage patients to be tested. Also included in the guidance statement is a recommendation that clinicians determine the need for additional screening on an individual basis

An updated radiocarbon-based ice margin chronology for the last deglaciation of the North American Ice Sheet Complex

The North American Ice Sheet Complex (NAISC; consisting of the Laurentide, Cordilleran and Innuitian ice sheets) was the largest ice mass to repeatedly grow and decay in the Northern Hemisphere during the Quaternary. Understanding its pattern of retreat following the Last Glacial Maximum is critical for studying many facets of the Late Quaternary, including ice sheet behaviour, the evolution of Holocene landscapes, sea level, atmospheric circulation, and the peopling of the Americas. Currently, the most up-to-date and authoritative margin chronology for the entire ice sheet complex is featured in two publications (Geological Survey of Canada Open File 1574 [Dyke et al., 2003]; ‘Quaternary Glaciations – Extent and Chronology, Part II’ [Dyke, 2004]). These often-cited datasets track ice margin recession in 36 time slices spanning 18 ka to 1 ka (all ages in uncalibrated radiocarbon years) using a combination of geomorphology, stratigraphy and radiocarbon dating. However, by virtue of being over 15 years old, the ice margin chronology requires updating to reflect new work and important revisions. This paper updates the aforementioned 36 ice margin maps to reflect new data from regional studies. We also update the original radiocarbon dataset from the 2003/2004 papers with 1541 new ages to reflect work up to and including 2018. A major revision is made to the 18 ka ice margin, where Banks and Eglinton islands (once considered to be glacial refugia) are now shown to be fully glaciated. Our updated 18 ka ice sheet increased in areal extent from 17.81 to 18.37 million km2, which is an increase of 3.1% in spatial coverage of the NAISC at that time. Elsewhere, we also summarize, region-by-region, significant changes to the deglaciation sequence. This paper integrates new information provided by regional experts and radiocarbon data into the deglaciation sequence while maintaining consistency with the original ice margin positions of Dyke et al. (2003) and Dyke (2004) where new information is lacking; this is a pragmatic solution to satisfy the needs of a Quaternary research community that requires up-to-date knowledge of the pattern of ice margin recession of what was once the world’s largest ice mass. The 36 updated isochrones are available in PDF and shapefile format, together with a spreadsheet of the expanded radiocarbon dataset (n = 5195 ages) and estimates of uncertainty for each interval

What Did Jesus Do: Answering Religious Conservatives Who Oppose Bullying Prevention Legislation

Conservative Christian organizations assert that anti-bullying programs are a stealth effort by gay activists to introduce into American schools an aggressive lesbian, gay, bisexual, transgender (LGBT) agenda. They contend that legislation and bullying prevention programs that mention gays are an attempt to indoctrinate children to embrace homosexual lifestyles; tolerate homosexual behavior; and celebrate homosexuality, bisexuality, and transgender identity. These voices are having an impact on state legislatures and the damage is immense. Educational research has made clear the devastating effects of bullying upon children, and LGBT students are among the most often targeted and least protected students. Given that schools are already failing to address bullying effectively, efforts to thwart protection of any group of students -- especially one that is routinely targeted -- is unconscionable. Yet these devoted Christians zealously interfere with protection of LGBT students from abuse by their peers and believe wholeheartedly that they are doing children and Christ a great service. We believe they fundamentally misunderstand three things: the dynamics of bullying, the law pertaining to student-on-student abuse, and the example and teachings of Christ. This Article addresses these misunderstandings. We propose a response to the distortions that are used to promote what is an anti-gay agenda that represents neither the teachings of the Bible nor the position of most Christians and evangelicals, whom these organizations purport to represent. Our hope is that, once the distortions are debunked, thinking Christians will reject the misguided efforts of a relatively few but influential individuals and organizations. If new voices can confront the misleading claims of anti-gay zealots with informed educational, legal, and Biblical responses, perhaps the distortions will be seen for what they are by Christians and non-Christians alike

Rotationally resolved infrared spectrum of the Li+_D2 cation complex

The infrared spectrum of mass selected Li +-D 2 cations is recorded in the D-D stretch region (2860-2950 cm -1) in a tandem mass spectrometer by monitoring Li + photofragments. The D-D stretch vibration of Li +-D 2 is shifted by -79 cm -1 from that of the free D 2 molecule indicating that the vibrational excitation of the D 2 subunit strengthens the effective Li +-D 2 intermolecular interaction. Around 100 rovibrational transitions, belonging to parallel K a=0-0, 1-1, and 2-2 subbands, are fitted to a Watson A-reduced Hamiltonian to yield effective molecular parameters. The infrared spectrum shows that the complex consists of a Li + ion attached to a slightly perturbed D 2 molecule with a T-shaped equilibrium configuration and a 2.035 A vibrationally averaged intermolecular separation. Comparisons are made between the spectroscopic data and data obtained from rovibrational calculations using a recent three dimensional Li +-D 2 potential energy surface [R. Martinazzo, G. Tantardini, E. Bodo, and F. Gianturco, J. Chem. Phys. 119, 11241 (2003)]