scholarly journals Concrete Strengthening by Introducing Polymer-Based Additives into the Cement Matrix—A Mini Review

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6071
Author(s):  
Weronika Kujawa ◽  
Ewa Olewnik-Kruszkowska ◽  
Jacek Nowaczyk
Keyword(s):  
Construction Industry ◽  
Chemical Structure ◽  
Current Knowledge ◽  
Polymeric Materials ◽  
Cement Matrix ◽  
Polymer Additives ◽  
Polymeric Additives ◽  
Different Types ◽  
Concrete Strengthening ◽  
Promising Type

The modern types of concrete are a mixture of aggregates, cement, water and optional additives and admixtures. In particular, polymer additives seem to be a promising type of component that can significantly change concrete and mortar properties. Currently, the most popular polymer additives include superplasticizers, latexes and redispersible powders. Moreover, in order to improve the properties of concrete-based composite admixtures, which enhance the resistance to cracking, polymer fibres and recycled polymers have been researched. All the types of polymeric materials mentioned above are broadly used in the construction industry. This work summarizes the current knowledge on the different types of popular polymeric additives. Moreover, it describes the correlation between the chemical structure of additives and the macro-behaviour of the obtained concrete.

Potential Uses of Vinegar as a Medicine and Related in vivo Mechanisms

2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Review Paper ◽  
Heart Diseases ◽  
Folk Medicine ◽  
Active Role ◽  
Current Review ◽  
Different Types ◽  
Positive Effect

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.

scholarly journals Electrochemically Produced Copolymers of Pyrrole and Its Derivatives: A Plentitude of Material Properties Using “Simple” Heterocyclic Co-Monomers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 281
Author(s):  
Tomasz Jarosz ◽  
Przemyslaw Ledwon
Keyword(s):  
Biological Activity ◽  
Material Properties ◽  
Building Block ◽  
Conjugated Polymer ◽  
Chemical Structure ◽  
Heterocyclic System ◽  
Repeat Unit ◽  
Polymeric Materials ◽  
Pyrrole Derivatives ◽  
Pyrrole Monomer

Polypyrrole is a classical, well-known conjugated polymer that is produced from a simple heterocyclic system. Numerous pyrrole derivatives exhibit biological activity, and the repeat unit is a common building block present in the chemical structure of many polymeric materials, finding wide application, primarily in optoelectronics and sensing. In this work, we focus on the variety of copolymers and their material properties that can be produced electrochemically, even though all these systems are obtained from mixtures of the “simple” pyrrole monomer and its derivatives with different conjugated and non-conjugated species.

scholarly journals Biopolymeric Materials Used as Nonviral Vectors: A Review

2021 ◽  
Vol 2 (1) ◽  
pp. 100-109
Author(s):  
Jailson de Araújo Santos ◽  
Daniel Barbosa Liarte ◽  
Alessandra Braga Ribeiro ◽  
Marcia dos Santos Rizzo ◽  
Marcília Pinheiro da Costa ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Web Of Science ◽  
Gene Transfection ◽  
Genetic Material ◽  
Nonviral Vectors ◽  
Cationic Polymers ◽  
Genetic Trait ◽  
Low Diversity ◽  
Different Types ◽  
Materials Used

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.

scholarly journals Melatonin in Cancer Treatment: Current Knowledge and Future Opportunities

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2506
Author(s):  
Wamidh H. Talib ◽  
Ahmad Riyad Alsayed ◽  
Alaa Abuawad ◽  
Safa Daoud ◽  
Asma Ismail Mahmod
Keyword(s):  
Clinical Trials ◽  
Current Knowledge ◽  
Biological Activities ◽  
Experimental Studies ◽  
Therapeutic Effects ◽  
Cell Proliferation Inhibition ◽  
Different Types ◽  
Solid Foundation

Melatonin is a pleotropic molecule with numerous biological activities. Epidemiological and experimental studies have documented that melatonin could inhibit different types of cancer in vitro and in vivo. Results showed the involvement of melatonin in different anticancer mechanisms including apoptosis induction, cell proliferation inhibition, reduction in tumor growth and metastases, reduction in the side effects associated with chemotherapy and radiotherapy, decreasing drug resistance in cancer therapy, and augmentation of the therapeutic effects of conventional anticancer therapies. Clinical trials revealed that melatonin is an effective adjuvant drug to all conventional therapies. This review summarized melatonin biosynthesis, availability from natural sources, metabolism, bioavailability, anticancer mechanisms of melatonin, its use in clinical trials, and pharmaceutical formulation. Studies discussed in this review will provide a solid foundation for researchers and physicians to design and develop new therapies to treat and prevent cancer using melatonin.

scholarly journals Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 773
Author(s):  
Ahmad Safwan Ismail ◽  
Mohammad Jawaid ◽  
Norul Hisham Hamid ◽  
Ridwan Yahaya ◽  
Azman Hassan
Keyword(s):  
Mechanical Properties ◽  
Phase Separation ◽  
Polymer Blends ◽  
Epoxy Polymer ◽  
Flexural Modulus ◽  
Polymeric Materials ◽  
Morphological Properties ◽  
Comparison Results ◽  
Unique Material ◽  
Different Types

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.

Influence of the Residue of Casting by Lost Wax in the Modulus of Elasticity and Porosity of Concretes

2014 ◽  
Vol 805 ◽  
pp. 343-349
Author(s):  
Carine F. Machado ◽  
Weber G. Moravia
Keyword(s):  
Construction Industry ◽  
Modulus Of Elasticity ◽  
Chemical Characterization ◽  
Microstructural Characterization ◽  
Cement Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardened State ◽  
Material Powder

This work evaluated the influence of additions of the ceramic shell residue (CSR), from the industries of Lost Wax Casting, in the modulus of elasticity and porosity of concrete. The CSR was ground and underwent a physical, chemical, and microstructural characterization. It was also analyzed, the environmental risk of the residue. In the physical characterization of the residue were analyzed, the surface area, and particle size distribution. In chemical characterization, the material powder was subjected to testing of X-ray fluorescence (XRF). Microstructural characterization was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The residue was utilized like addition by substitution of cement in concrete in the percentages of 10% and 15% by weight of Portland cement. It was evaluated properties of concrete in the fresh and hardened state, such as compressive strength, modulus of elasticity, absorption of water by total immersion and by capillarity. The results showed that the residue can be used in cement matrix and improve some properties of concrete. Thus, the CSR may contribute to improved sustainability and benefit the construction industry.

Adhesives for the Installation of Cast Basalt Elements on Metal and Comparison of Properties when Using Different Types of Fillers

2021 ◽  
Vol 898 ◽  
pp. 35-41
Author(s):  
Jakub Hodul ◽  
Tomáš Žlebek ◽  
Lenka Mészárosová ◽  
Aleš Jakubík ◽  
Rostislav Drochytka
Keyword(s):  
Construction Industry ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Mineral Admixtures ◽  
Maximum Efficiency ◽  
Organic Additives ◽  
Metal Base ◽  
Secondary Raw Materials ◽  
Ecological Benefit ◽  
Different Types

The polymeric adhesives for the installation of basalt elements on a metal base are designed primarily for environments with increased chemical and mechanical stress. They are composed of polymer resins (epoxy, polyurethane) as binders, as well as organic additives and mineral admixtures that mainly fulfill the function of filler. In all sectors of today's construction industry, maximum efficiency in the production of materials is required for sustainability purposes, which, however, must never be at the expense of the quality or the required performance. Due to these requirements, great emphasis is placed on the maximum use of secondary raw materials. Talc is used as the primary filler for polymer adhesives. Sawdust, tire rubber, and fly ash are used as secondary raw materials. The use of these in building supplies can positively affect some physical and mechanical properties of polymeric adhesives. Also, the use of secondary raw materials has the above-mentioned ecological benefit. Basic properties, such as bulk density and adhesion to both metallic and basalt elements, were monitored. The details of the cohesion of the adhesive with the bonded material, as well as the distribution of secondary raw materials in the polymer matrix, were assessed microscopically.

scholarly journals MICROSCOPIC FEATURES OF CEMENT PASTE MODIFIED BY FINE PERLITE

2016 ◽  
Vol 7 ◽  
pp. 12
Author(s):  
Vladimír Hrbek ◽  
Veronika Koudelková ◽  
Pavel Padevět ◽  
Petr Šašek
Keyword(s):  
Electron Microscopy ◽  
Construction Industry ◽  
Lightweight Aggregate ◽  
Cement Matrix ◽  
Instrumented Indentation ◽  
Cement Sample ◽  
Cement Material ◽  
Material Development ◽  
Microscopic Features ◽  
Cement Binder

The use of waste material and replacement of binder element in cementitious composites is in focus of material development. Perlite in the construction industry is usually used in form of lightweight aggregate enhancing the insulating performance of concrete. This paper focuses on integration of fine perlite into the cement matrix and possible replacement of the cement binder in the composition of the material. The macromechanical performance of the modified paste is tested on specimens with 5, 10, 15 and 20% fine perlite substitution and pure cement sample. To distinguish the effect of the perlite on the microstructural level, pure cement material and specimen containing 10% of fine perlite are investigated by the electron microscopy. Furthermore, the mechanical properties of individual phases are examined and compared on same samples by instrumented indentation. The presented results enabled estimation of fine perlite impact on the macro and microscopic performance of the material.

Mafia infiltration, public administration and local institutions: A comparative study in Northern Italy

2018 ◽  
Vol 17 (5) ◽  
pp. 540-562 ◽  
Author(s):  
Joselle Dagnes ◽  
Davide Donatiello ◽  
Valentina Moiso ◽  
Davide Pellegrino ◽  
Rocco Sciarrone ◽  
...  
Keyword(s):  
Public Administration ◽  
Construction Industry ◽  
Social Relations ◽  
Local Level ◽  
Northern Italy ◽  
Comparative Case Study ◽  
Local Institutions ◽  
Opportunity Structure ◽  
Different Types

Nuanced explanations of the factors underpinning the mafia’s movements across territories have recently been proposed. However, more light must be shed on the mechanisms through which mafiosi try to infiltrate the legal economy in non-traditional territories. Accordingly, this study aims to micro-found interactions and exchanges that mainly involve mafiosi, politicians and economic actors in expansion areas. Focusing on the local level, we will show how the misuse of several administrative tools generates a profitable opportunity structure for mafiosi. To this end, we present an in-depth comparative case study of three events involving the construction industry that took place in Northern Italy. The main findings show that: (i) mafiosi are skilled at smoothing social relations, enlarging and consolidating opaque networks predating their arrival; (ii) they give rise to different types of mutual exchanges and network structures.

scholarly journals Engineering project networks: providing “sustainable work systems” for construction knowledge workers

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Reza Hosseini ◽  
David John Edwards ◽  
Tandeep Singh ◽  
Igor Martek ◽  
Amos Darko
Keyword(s):  
Construction Industry ◽  
Current Knowledge ◽  
Work Life ◽  
Quality Of Work Life ◽  
Work Place ◽  
Future Research ◽  
Engineering Project ◽  
Content Type ◽  
Project Networks ◽  
Life Issues

Purpose The construction industry faces three emergent developments that in all likelihood will transform the industry into the future. First, engineering project networks (EPNs), in which teams collaborate on projects remotely in time and space, are transforming global construction practices. Second, as a major consumer of resources and significant producer of green-house gases, construction is under pressure to reduce its carbon footprint. Third, the construction industry presents as one of the least socially sustainable work environments, with high job dissatisfaction, skewed work–life balance and over representation of depressive and mental disorders. It is incumbent on the industry to reconcile these issues. Specifically, what scope is there to shape the evolution of EPNs towards a configuration that both promotes sustainability generally, and enhances quality of work-life issues, while at the same time continuing to apprehend the economic dividends for which it is adopted? As salient as this question is, it has not been broached in the literature. Therefore, this study aims to survey the extent to which EPNs align with the sustainability agenda, more broadly, and that of employee work-place satisfaction, more specifically. Design/methodology/approach A literature review of current knowledge of these concerns is explored and a summative assessment presented. Findings To the best of the authors’ knowledge, as the first in its kind, the study brings to light that EPNs go a long way towards facilitating economic objectives, part way towards realising ecological and sociological objectives but make hardly any impact on improving employee work satisfaction. Originality/value This paper examines an entirely novel area that has not been studied yet. Future research should take up this finding to determine how EPNs may be further adapted to accommodate these wider necessary objectives.

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