다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

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The Environmental Protection Agency

Non-destructive testing of concrete structures

Experimental data on compressive strength and ultrasonic pulse velocity properties of sustainable mortar made with high content of GGBFS and CKD combinations.

Structural health monitoring (SHM) is an important aspect of the assessment of various structures and infrastructure, which involves inspection, monitoring, and maintenance to support economics, quality of life and sustainability in civil engineering. Currently, research has been conducted in order to develop non-destructive techniques for SHM to extend the lifespan of monitored structures. This paper will review and summarize the recent advancements in non-destructive testing techniques, namely, sweep frequency approach, ground penetrating radar, infrared technique, fiber optics sensors, camera-based methods, laser scanner techniques, acoustic emission and ultrasonic techniques. Although some of the techniques are widely and successfully utilized in civil engineering, there are still challenges that researchers are addressing. One of the common challenges within the techniques is interpretation, analysis and automation of obtained data, which requires highly skilled and specialized experts. Therefore, researchers are investigating and applying artificial intelligence, namely machine learning algorithms to address the challenges. In addition, researchers have combined multiple techniques in order to improve accuracy and acquire additional parameters to enhance the measurement processes. This study mainly focuses on the scope and recent advancements of the Non-destructive Testing (NDT) application for SHM of concrete, masonry, timber and steel structures.

Recent Advancements in Non-Destructive Testing Techniques for Structural Health Monitoring

The Combined Effect of CKD and Silica Fume on the Mechanical and Durability Performance of Cement Mortar

The permeable pavement seems to be an established stormwater management solution that may be utilized in parking and low-traffic areas. These pavements can reduce the amount of runoff that reduces the environmental impact compared with a traditional drainage system. Traditional drainage systems, which carry stormwater runoff quickly to a stream by piped systems, cause increases in runoff volume, peak flow, and pollutants are taken to rivers. This paper tests permeable asphalt pavement in a purpose-designed laboratory apparatus. To understand the hydraulic flow conditions and the runoff performance that occurred within two layers of permeable and conventional pavement. The thickness of the permeable layer is 25, 37.5, and 50 mm, and the conventional layer is 80mm. An artificial rainfall covering an area of 1.5 ×1.0 m2 is constructed to study the relationship between surface runoff and subsurface runoff from a permeable pavement under different geometric design parameters of a roadway. Five slopes set at 0.0, 2.5, 5.0, 7.5 and 10 % in a short direction, and four discharge as 20, 40,60 and 80 L/min are tested. The result demonstrated that 50 mm thickness is suitable for permeable asphalt pavement under the most slope, increasing subsurface runoff and decreasing surface runoff water.

https://igj-iraq.org/igj/index.php/igj/article/download/834/937

Assessment of Surface and Subsurface Drainage from Permeable Friction Course (As a Sustainable Pavement) under Different Geometric and Hydrologic Conditions

Maintaining the optimum temperature in the living quarters is the key to a comfortable stay. Due to the lack of a central heating system or in the event of its insufficiency, they resort to the installation of additional heat sources. There is a wide range of devices on the market with different operating principles, hence the difficulty of which is better - a convector or infrared heater. A comparative analysis of devices will help you make the right choice. Asking the question of which is better a convection heater or an infrared heater, one must decide on its role in heating the house. It is better to use them as additional equipment with an existing heating system. One of the effective sources of additional heating are infrared radiators. Its principle of operation is based on infrared radiation, which provides a quick and qualitative increase in temperature in any part of your apartment. Today, more and more people prefer infrared radiators. From the usual electric convector, they differ in that they heat not the air in the room, but hard surfaces (floors, walls) and objects, and these, in turn, leak heat into the surrounding space. So, the entire room is heated up unnoticeably.

Sustainable heating system by infrared radiators

The technique of replacing the cement with other alternative materials focuses on the production of materials with similar performance and reduced environmental impacts relative to traditional cement. The main aim of this study is to investigate the effect of replacing the cement content with high volume of Pulverised Fuel Ash (PFA) on the mechanical performance of cement mortar. Three mixtures were prepared with different percentages of PFA (20%, 40% and 60%) as replacement of cement along with other mixture that made with 100% cement as a control mixture. In order to evaluate the performance of the cement mortars, compressive strength and Ultrasonic Pulse Velocity (UPV) tests after 7, 14 and 28 days of curing was used. The results indicated that for all ages of curing, the increase of PFA contents caused a reduction in the compressive strength and UPV in comparison with the control mixture. After 28 days of curing, the results indicated that the mixture incorporated 20% PFA has similar UPV value relative to the control mixture. Such findings will significantly contribute in reducing the cost of the produced mortar by reducing the amount of used cement and this consequently reduce the cement demands/manufacturing. Less production of cement will reduce the Carbon Dioxide (CO2) emissions of the cement industry.

Early age assessment of cement mortar incorporated high volume fly ash

This research aims to stabilize clayey soil utilizing fluid catalytic cracking with an unchangeable ordinary portland cement ratio of 3 percent. A soft clayey soil was blended with 1.5, 3, 4.5, and 6 percent of fluid catalytic cracking by the dry stabilized soil weight, the ordinary portland cement amount has been fixed at 3 percent. The adding of different FCC ratios impact cement stabilized soil evaluated based on the results of unconfined-compressive-strengths test that gained after curing for 7 and 28 days. It was noticeable from the results that the best combination is the combination of soil remedied with 3 percent of each cement and FCC in improving the compressive strengths from 249.80 to 806.20k Pa for the stabilized soil after curing for 28 days. The most highlighting soil binder combination was analyzed utilizing scanning electron microscopy. It was noticed from the scanning electron microscopy results; cementitious materials were produced after 7 days of curing and improved more after curing for eight days.

Zainab S. Al-Khafaji

Papers

The Combined Effect of CKD and Silica Fume on the Mechanical and Durability Performance of Cement Mortar

Assessment of Surface and Subsurface Drainage from Permeable Friction Course (As a Sustainable Pavement) under Different Geometric and Hydrologic Conditions

Sustainable heating system by infrared radiators

Early age assessment of cement mortar incorporated high volume fly ash

Soft Soil Treated with Waste Fluid Catalytic Cracking as a Sustainable Stabilizer Material