Portland Cement Association

<h2>Abstract</h2><h3>Aim</h3> To evaluate the drug release capacity and the antibacterial properties of incorporating chlorhexidine digluconate (CHX) liposomal formulation in a calcium hydroxide-based root canal sealer. <h3>Methods</h3> The sealers tested were SEALAPEX and APEXIT, containing 1 % of the different liposomal formulations. The drug release capacity was assessed by Rhodamine B detection and CHX detection by spectrophotometer, and the antibacterial properties by agar diffusion test (ADT), direct contact test (DCT), and modified direct contact test (MDCT). <h3>Results</h3> The best release profile was found for the SEALAPEX with the liposomal formulation using the 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)/L-α-phosphatidylcholine hydrogenated (HSPC). This liposomal formulation containing 4 % CHX improved the antibacterial properties of SEALAPEX compared to non-encapsulated CHX and control. <h3>Conclusion</h3> The liposomal formulation increased the release of CHX, improving the antibacterial effect of the SEALAPEX, representing a promising strategy for local anti-biofilm therapy in the endodontic field.

Electronic resource reviews written by librarians are a valuable way to identify potential content platforms and stay current on new resources. Resource-focused articles can also assist with learning about useful features, training others, and marketing to potential user groups. However, articles evaluating or highlighting innovative uses of resources may be published in disparate journals or online platforms and are not collocated. Small or solo-staffed libraries may not subscribe to library and information sciences databases or journals that contain reviews of electronic resources. And many of these reviews or other useful articles are open access. With this in mind, the main aim of the LERRN citation database was to create a freely available citation database that brings together electronic resource reviews and other content that can assist librarians in appraising and using electronic resources.

Cement and concrete are all around us, from sidewalks and buildings to runways and dams, and yet most of us hardly stop

Particle size reduction is one of the most energy intensive and inefficient processes in use today. Traditional means for calculating energy requirements used for sizing equipment rely on empirically derived formulas and indices. The standard work indices of Kick, Bond and Von Rittinger each work within specific particle size ranges based on empirically derived factors. To date the true energy required for size reduction alone is still unknown. Because of this the true efficiency of size reduction processes are also unknown. Fundamental research at the Massachusetts Institute of Technology's (MIT) Concrete Sustainability Hub (CSH) is taking a closer look at the theoretical power required for particle size reduction on the micro scale. This work has the potential to greatly reduce the power required for cement manufacture. This paper reviews the MIT research and discusses the possible implications and next steps for that work.

This paper addresses the implementation of a mining software package at the Colton Quarry and discusses the advantages and benefits that have been realized by management and engineering personnel in both day-to-day mining operations and long term strategic planning. The paper describes how the implementation has progressed from initial installation to its current state and continuing developments.

Abstract The purpose of a management team is to provide continuous feedback to the instructor on two major issues: instructor performance and course structure and content. Successful student management team projects at the University of Wisconsin, University of Colorado and University of Minnesota have demonstrated that team members working together for the good of the class can accomplish a great deal. In the Michigan State University pilot project, the student management teams operated during a 15‐week course on construction materials. This is a 4‐credit required junior level course for all Civil Engineering majors and has both a classroom and a laboratory component. The average class size is thirty‐five students. The team met every week for about thirty to forty‐five minutes over the course of the semester. Their principal assignment was to improve the quality of the course by collecting data through classroom assessment techniques and regular group discussions with the instructor. It was clear from the formative surveys that 85% and 88% of the students were comfortable (level of understanding between 4–5) with the material “uncovered” in the Portland cement concrete (PCC) and hot mix asphalt concrete (HMAC) modules respectively. This paper discusses the concept of management teams along with other details in developing the management teams and results from the pilot study.

The users of soil-cement in the water resources application have broadened over the past years. Still one construction related task has remained essentially the same: quality control. Soil-cement is a highly compacted mixture of soil; usually sand, Portland cement, and water. It has the properties of a low-strength concrete. Without adequate controls on the quality of the materials and construction methods, the performance of the project may not meet expectations. A successful soil-cement project begins with the development of a quality control program with the responsibilities of each party clearly defined. The quality control plan should address submittals which must receive approval from the project engineer; mixture proportioning considerations; minimum requirements for equipment such as the mixing plant, compactors, and curing equipment; types and frequencies of material testing; and acceptance criteria for construction procedures and individual material tests. Quality control practices during construction do hot have to negatively impact the contractor's production. Each member of the project team, from the laborer to the project manager, can be aware and trained in his or her responsibilities to ensure a quality product. The benefits of having everyone on the project buy into and execute their responsibilities will minimize any rework and ensure that the performance criteria will be met or exceeded. This paper will focus on quality control issues where soil-cement is used for bank stabilization grade control structures and slope protection. Issues involving mixing of soil-cement will be directed at central plant pugmills.

A numerical method has been developed for the prediction of coupled heat and mass transfer and related processes in porous media exposed to elevated temperatures. The computer model predictions have been validated against experimental results of carbonate aggregate concrete slabs subjected to the ASTM E119 standard fire exposure. Output from the model depicts the coupled relationships between the temperature, moisture content, and pore pressure histories and distributions. This article investigates the numerical effect of grid spacing on the pore pressure fluctuations and the influence of the pore pressure on the spalling potential of concrete exposed to elevated temperatures.

A mathematical and computational model simulating the coupled heat and mass transfer and related processes in porous media exposed to elevated temperatures has been developed. Taking into account the conservation of mass, momentum, and energy, and the evaporation of free and chemically bound water released by dehydration and their effect on the transport phenomena, a set of three coupled nonlinear differential equations is obtained. Carbonate aggregate concrete slabs subjected to the ASTM E119 standard fire exposure are modeled and validated against test data. Output depicts the coupled relationships between the material's temperature, moisture content, and pore pressure histories and distributions. Language: en