scholarly journals A Review of Recent Developments and Advances in Eco-Friendly Geopolymer Concrete

2020 ◽  
Vol 10 (21) ◽  
pp. 7838
Author(s):  
Lahiba Imtiaz ◽  
Sardar Kashif Ur Rehman ◽  
Shazim Ali Memon ◽  
Muhammad Khizar Khan ◽  
Muhammad Faisal Javed

The emission of CO2 and energy requirement in the production of Ordinary Portland Cement (OPC) causes the continuous depletion of ozone layer and global warming. The introduction of geopolymer concrete (GPC) technology in the construction industry leads to sustainable development and cleaner environment by reducing environmental pollution. In this article, constituents of GPC and their influence on properties of GPC has been reviewed critically. Fresh and hardened properties of GPC as well as the factors influencing these properties are discussed in detail. Flow charts have been proposed to show which factors have higher/lower impact on the fresh and hardened properties of GPC. A comprehensive review on the mix design of GPC, nanomaterial-based GPC, 3D printing using GPC, reinforced GPC and Global warming potential (GWP) assessment was conducted. Finally, the practical applications of GPC in the construction industry are provided.

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4547
Author(s):  
Aneta Skoratko ◽  
Jacek Katzer

Additive manufacturing has been of increasing interest to the construction industry for the last ten years. The subject of the research is the printing of concrete, metals, and plastics. In their analysis and research, authors have focused on printing plastics. 3D printing of reinforcement of concrete elements made of plastics can significantly improve the efficiency of their erection, reduce the amount of waste, and optimize their shape. In this paper, recent developments in the 3D printing of plastics for construction are reviewed. Various applications were discussed, including unconventional spatial reinforcement (impossible to achieve in a traditional way), printed permanent formwork, etc. The challenges for further research and practical applications of such solutions were also discussed.


2020 ◽  
Vol 5 ◽  
pp. 17-25
Author(s):  
Branko Savija

Additive manufacturing has been a topic of interest in the construction industry for the past decade. 3D printing of concrete structures promises great improvements in construction efficiency, waste reduction, and shape optimization. Another field where additive manufacturing offers opportunities is on the material level of cementitious composites. Techniques developed in other fields can be used to create multifunctional cementitious composites beyond what is possible with conventional technologies. This letter reviews recent developments in the field. Different applications are discussed: creating reinforcement for cementitious composites, creating capsules and vascular networks, and cementitious composites with superior mechanical behavior. Challenges for further research and practical applications of such materials are also discussed.


Author(s):  
Daniel Johnson

This chapter on assessing student learning and Orff Schulwerk examines the foundations of this approach, its focus on creativity, and practical applications of this pedagogy. By reviewing current research literature and international adoptions of the Schulwerk, the chapter focuses on three assessment-related challenges: a lack of clearly defined teaching practices, a de-emphasis of evaluation in the Orff process, and inherent challenges related to assessing creativity. An examination of professional resource documents and recent developments in national standards provides ways to address each of these assessment challenges in Orff-based instruction. A discussion of curricular levels offers more possibilities for enhancing authentic assessment strategies. Practical recommendations for Orff Schulwerk teachers to improve their assessment protocols and implications for teacher-educators conclude this chapter.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 484
Author(s):  
Syed Arif Hussain Rizvi ◽  
Justin George ◽  
Gadi V. P. Reddy ◽  
Xinnian Zeng ◽  
Angel Guerrero

Since the first identification of the silkworm moth sex pheromone in 1959, significant research has been reported on identifying and unravelling the sex pheromone mechanisms of hundreds of insect species. In the past two decades, the number of research studies on new insect pheromones, pheromone biosynthesis, mode of action, peripheral olfactory and neural mechanisms, and their practical applications in Integrated Pest Management has increased dramatically. An interdisciplinary approach that uses the advances and new techniques in analytical chemistry, chemical ecology, neurophysiology, genetics, and evolutionary and molecular biology has helped us to better understand the pheromone perception mechanisms and its practical application in agricultural pest management. In this review, we present the most recent developments in pheromone research and its application in the past two decades.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1449
Author(s):  
Wenfeng Wang ◽  
Shaochan Duan ◽  
Haoran Zhu

In order to improve the durability of the asphalt pavement on a cement concrete bridge, this study investigated the effect of the modulus of the asphalt mixture at the bottom layer on the mechanical response of bridge pavement, along with a type of emerging bridge pavement structure. In addition, the design method and pavement performance of a high-modulus asphalt mixture were investigated using laboratory and field tests, and the life expectancy of the deck pavement structure was predicted based on the rutting deformation. The results showed that the application of a high-modulus asphalt mixture as the bottom asphalt layer decreased the stress level of the pavement structure. The new high-modulus asphalt mixture displayed excellent comprehensive performance, i.e., the dynamic stability reached 9632 times/mm and the fatigue life reached 1.65 million cycles. Based on the rutting depth prediction, using high-modulus mixtures for the bridge pavement prolonged the service life from the original 5 years to 10 years, which significantly enhanced the durability of the pavement structure. These research results could be of potential interest for practical applications in the construction industry.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1145
Author(s):  
Yuan Zhao ◽  
Xuecheng Zhu ◽  
Wei Jiang ◽  
Huilin Liu ◽  
Baoguo Sun

With the rapid development of global industry and increasingly frequent product circulation, the separation and detection of chiral drugs/pesticides are becoming increasingly important. The chiral nature of substances can result in harm to the human body, and the selective endocrine-disrupting effect of drug enantiomers is caused by differential enantiospecific binding to receptors. This review is devoted to the specific recognition and resolution of chiral molecules by chromatography and membrane-based enantioseparation techniques. Chromatographic enantiomer separations with chiral stationary phase (CSP)-based columns and membrane-based enantiomer filtration are detailed. In addition, the unique properties of these chiral resolution methods have been summarized for practical applications in the chemistry, environment, biology, medicine, and food industries. We further discussed the recognition mechanism in analytical enantioseparations and analyzed recent developments and future prospects of chromatographic and membrane-based enantioseparations.


2019 ◽  
Vol 11 (21) ◽  
pp. 6082 ◽  
Author(s):  
Judith Rosenow ◽  
Hartmut Fricke

Contrails are one of the driving contributors to global warming, induced by aviation. The quantification of the impact of contrails on global warming is nontrivial and requires further in-depth investigation. In detail, condensation trails might even change the algebraic sign between a cooling and a warming effect in an order of magnitude, which is comparable to the impact of aviation-emitted carbon dioxides and nitrogen oxides. This implies the necessity to granularly consider the environmental impact of condensation trails in single-trajectory optimization tools. The intent of this study is the elaboration of all significant factors influencing on the net effect of single condensation trails. Possible simplifications will be proposed for a consideration in single-trajectory optimization tools. Finally, the effects of the most important impact factors, such as latitude, time of the year, and time of the day, wind shear, and atmospheric turbulence as well as their consideration in a multi-criteria trajectory optimization tool are exemplified. The results can be used for an arbitrary trajectory optimization tool with environmental optimization intents.


2011 ◽  
Vol 6 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Karin du Plessis

To date there has been a theoretical and empirical gap in workplace-centered health promotion research—particularly as it applies to blue-collar men’s diets. To begin addressing the paucity of research, five qualitative focus groups ( N = 53) were conducted in Australian training colleges to explore the dietary behaviors of apprentices. Thematic analysis was used by the researcher who concludes that although some apprentices were health conscious and attempted to eat healthy foods, many had diets high in saturated fats and sugar. These types of diets are associated with increased risks for developing chronic disease and are associated with decreased life expectancy. As such it poses a serious challenge for health promoters. Apprentices’ dietary practices were also found to be moderated by convenience, availability, and cost of foods in their environment. Their nutritional beliefs, significant others, colleagues in the workplace, and their body image also influence their food choices.


2016 ◽  
Vol 32 (1) ◽  
Author(s):  
Yuehao Luo ◽  
Xia Xu ◽  
Dong Li ◽  
Wen Song

AbstractWith the rapid development of science and technology, increasing research interests have been focused on environment protection, global warming, and energy shortage. At present, reducing friction force as much as possible has developed into an urgent issue. Sharkskin effect has the potential ability to lower viscous drag on the fluid-solid interface in turbulence, and therefore, how to fabricate bio-inspired sharkskin surfaces is progressively becoming the hot topic. In this review, various methods of fabricating drag reduction surfaces covering biological sharkskin morphology are illustrated and discussed systematically, mainly involving direct bio-replicated, synthetic fabricating, bio/micro-rolling, enlarged solvent-swelling, drag reduction additive low-releasing, trans-scale enlarged three-dimensional fabricating, flexible printing, large-proportional shrunken bio-replicating, ultraviolet (UV) curable painting, and stretching deformed methods. The overview has the potential benefits in better acquainting with the recent research status of fabricating sharkskin surfaces covering the biological morphology.


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