scholarly journals Correlating the Performance of a Fire-Retardant Coating across Different Scales of Testing

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2271 ◽  
Author(s):  
Yan Hao Ng ◽  
Indraneel Suhas Zope ◽  
Aravind Dasari ◽  
Kang Hai Tan
Keyword(s):  
Steel Substrate ◽  
Thermal Characteristics ◽  
Fire Retardant ◽  
Acrylic Resin ◽  
Expandable Graphite ◽  
Coating Materials ◽  
Significant Difference ◽  
Protective System ◽  
Definition Of ◽  
Structural Scale

Material-scale tests involving milligrams of samples are used to optimize fire-retardant coating formulations, but actual applications of these coatings require them to be assessed with structural-scale fire tests. This significant difference in the scale of testing (milligrams to kilograms of sample) raises many questions on the relations between the inherent flammability and thermal characteristics of the coating materials and their “performance” at the structural scale. Moreover, the expected “performance” requirements and the definition of “performance” varies at different scales. In this regard, the pathway is not established when designing and formulating fire-retardant coatings for structural steel sections or members. This manuscript explores the fundamental relationships across different scales of testing with the help of a fire-protective system based on acrylic resin with a typical combination of intumescent additives, viz. ammonium polyphosphate, pentaerythritol, and expandable graphite. One of the main outcomes of this work dictates that higher heat release rate values and larger amounts of material participating in the pyrolysis process per unit time will result in a rapid rise in steel substrate temperature. This information is very useful in the design and development of generic fire-retardant coatings.

Enhancing the Char Resistant of Expandable Graphite Based Intumescent Fire Retardant Coatings by Using Multi-Wall Carbon Nano Tubes for Structural Steel

2012 ◽  
Vol 185 ◽  
pp. 90-93 ◽  
Author(s):  
Sami Ullah ◽  
Faiz Ahmad
Keyword(s):  
Fire Test ◽  
Steel Substrate ◽  
Thermo Gravimetric Analysis ◽  
Fire Retardant ◽  
Steel Structure ◽  
Vital Role ◽  
Shielding Effect ◽  
Expandable Graphite ◽  
Gravimetric Analysis ◽  
Multi Wall Carbon Nanotubes

In the intumescent fire retardant (IFR) coating char thickness and its strength play a vital role to protect the base steel structure from the fire. The IFR coating contains expandable graphite (EG), ammonium polyphosphate (APP), melamine, boric acid, bisphenol, epoxy resin BE-188 (BPA) which is used as a binder with ACR hardener H-2310 polyamide amine and multi wall carbon nanotubes (MWCNTs). A range of different formations were prepared to study the heat shielding effect and char expansion after fire test. The intumescent coating was tested at 800°C for one hour in the furnace and found to be very stable and well bonded with the steel substrate. The characterization was done by using Thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FESEM) after fire test. The results confirmed that MWCNTs enhanced the char resistant of IFR coating on steel substrate after fire test. Keywords: Intumescent fire retardant coating, Expandable Graphite, Multiwall Carbonnano tubes, FESEM and TGA.

The Effect of Wollastonite Filler on Thermal Performance of Intumescent Fire Retardant Coating

2014 ◽  
Vol 970 ◽  
pp. 328-331 ◽  
Author(s):  
Muhammad Zia-ul-Mustafa ◽  
Faiz Ahmad ◽  
Puteri S. M. Megat-Yusoff ◽  
Hammad Aziz
Keyword(s):  
Fire Test ◽  
Steel Substrate ◽  
Fire Retardant ◽  
Expandable Graphite ◽  
Coated Steel ◽  
Fire Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Blowing Agent ◽  
Thermal Stability Of

Various types of intumescent fire retardant coatings (IFRCs) have been used to protect the substrates exposed to fire. In current study, high temperature filler Wollastonite (W) filler was used to improve fire performance of intumescent fire retardant coating. The basic ingredients of the coating were ammonium poly-phosphate (APP) as acid source, expandable graphite (EG) as carbon source, melamine (MEL) as blowing agent in epoxy binder, boric acid as additive and hardener as curing agent. In this study a range of coating formulations were developed by using different weight percentages of Wollastonite filler. The coated steel substrate samples were tested for fire performance using Bunsen burner and char expansion was measured using furnace fire test. Composition of the char was determined by X-ray diffraction (XRD) technique. The char morphology was studied using field emission scanning electron microscopy (FESEM). Results showed that Intumescent coating with addition of Wollastonite filler enhanced anti-oxidation of the char. Presence of phosphorus, calcium and silicon in char layer further improved the thermal stability of char.

Effect of Titanium Oxide on Fire Performance of Intumescent Fire Retardant Coating

2014 ◽  
Vol 935 ◽  
pp. 224-228 ◽  
Author(s):  
Hammad Aziz ◽  
Faiz Ahmad ◽  
Muhammad Zia-ul-Mustafa
Keyword(s):  
Bisphenol A ◽  
Titanium Oxide ◽  
Steel Substrate ◽  
Research Work ◽  
Fire Retardant ◽  
Expandable Graphite ◽  
Curing Agent ◽  
Fire Performance ◽  
Bunsen Burner ◽  
Weight Percentage

The objective of this research work was to study the thermal efficiency of intumescent fire retardant coating (IFRC) designed to protect structural steel in event of fire. IFRC has been effectively developed by using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL), boric acid (BA), titanium oxide (TiO2), and bisphenol A BE-188 with polyamide amine H-2310 as curing agent. Six formulations were developed using different weight percentage (wt. %) of TiO2 and samples were tested for char expansion in furnace at 500°C for 2 h. Bunsen burner test was used to investigate the thermal performance of coating and its performance was compared by using thermal margin value. FESEM was used for char morphology. Char composition was analyzed by XRD and FTIR. Results showed that the coating with 4 wt. % of TiO2 provides better thermal insulation to the steel substrate.

Synergistic Effects of Titanium Dioxide and Zinc Borate on Thermal Degradation and Water Resistance of Epoxy Based Intumescent Fire Retardant Coatings

2017 ◽  
Vol 740 ◽  
pp. 41-47 ◽  
Author(s):  
Norlaili Amir ◽  
Faiz Ahmad ◽  
Muhammad Hazwan Abdul Halim ◽  
Qandeel Fatima Gillani ◽  
Puteri S.M. Megat Yusoff ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Water Resistance ◽  
Sea Water ◽  
Synergistic Effects ◽  
Steel Substrate ◽  
Water Immersion ◽  
Fire Retardant ◽  
Zinc Borate ◽  
Expandable Graphite ◽  
Bunsen Burner

Abstract. This studies discuss the synergistic effects of titanium dioxide (TiO2) and zinc borate on thermal stability and water resistance of intumescent fire retardant coatings. TiO2 in association with a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine/ zinc borate (APP–EG–MEL-ZB) was introduced to epoxy based coatings to improve the fire resistance. The influences of TiO2 on the properties of the coatings were investigated in detail by using Bunsen burner fire test, thermogravimetric analysis (TGA), scanning electron microscope (SEM) and water immersion test. Bunsen burner test revealed that incorporation of titanium dioxide in intumescent formulation reduced the steel substrate temperature from 240 °C to 116 °C. The TGA results proved that addition of TiO2 could enhance the anti-oxidation of the char layers and increase the residue weights of the coatings. The FESEM images demonstrated that addition of TiO2 could improve the foam structure of the char residue. Sea water resistance test demonstrated that the optimum mass % age of TiO2 (6%) exhibited great synergism with natural anti-corrosion agent, zinc borate, and improved corrosion resistance performance of intumescent coating formulations.

scholarly journals Shear bond strength of novel calcium aluminate-based cement (EndoBinder) to root dentine

2014 ◽  
Vol 08 (04) ◽  
pp. 498-503 ◽  
Author(s):  
Lucas da Fonseca Roberti Garcia ◽  
Hebert Luis Rossetto ◽  
Fernanda de Carvalho Panzeri Pires-de-Souza
Keyword(s):  
Bond Strength ◽  
Calcium Aluminate ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Mineral Trioxide Aggregate ◽  
Acrylic Resin ◽  
Promising Alternative ◽  
Mean Values ◽  
Significant Difference ◽  
Molar Teeth

ABSTRACT Objective: To evaluate the shear bond strength of a novel calcium aluminate-based cement, EndoBinder (EB), to dentine in comparison with Grey and White Mineral Trioxide Aggregate (MTA). Materials and Methods: Root canal hemi-sections obtained from 30 extracted molar teeth were embedded in self-polymerized acrylic resin and were grounded wet in order to obtain a flat dentine surface. Next, the roots were randomly assigned into three groups (n = 10), according to the cement used, as follows: EB: EndoBinder; WMTA: White MTA and GMTA: Grey MTA. The shear bond strength test was performed using a Universal Testing Machine (0.5 mm/min) and the data were submitted to statistical analysis (1-way ANOVA and Tukey tests, P < 0.05). Results: EB presented the highest shear bond strength values; however, there was no statistically significant difference in comparison with GMTA (P > 0.05). WMTA presented the lowest mean values, which were significant in comparison with EB (P < 0.05). Conclusions: The novel calcium aluminate-based cement presented higher shear bond strength than WMTA, and should be considered as a promising alternative in endodontic therapy.

Effects of expandable graphite on char morphology and pyrolysis of epoxy based intumescent fire‐retardant coating

2021 ◽  
pp. 51206
Author(s):  
Sami Ullah ◽  
Faiz Ahmad ◽  
Abdullah G. Al‐Sehemi ◽  
Muhammad Rafi Raza ◽  
Mohammed Ali Assiri ◽  
...  
Keyword(s):  
Fire Retardant ◽  
Expandable Graphite

Infodemic surrounding COVID-19: Can LIS students recognize and categorize “problematic information” types on social media?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shamima Yesmin ◽  
S.M. Zabed Ahmed
Keyword(s):  
Social Media ◽  
Online Survey ◽  
Information Science ◽  
Wrong Answer ◽  
Student Groups ◽  
Content Type ◽  
Correct Definition ◽  
Significant Difference ◽  
Definition Of ◽  
And Task

Purpose The purpose of this paper is to investigate Library and Information Science (LIS) students’ understanding of infodemic and related terminologies and their ability to categorize COVID-19-related problematic information types using examples from social media platforms. Design/methodology/approach The participants of this study were LIS students from a public-funded university located at the south coast of Bangladesh. An online survey was conducted which, in addition to demographic and study information, asked students to identify the correct definition of infodemic and related terminologies and to categorize the COVID-related problematic social media posts based on their inherent problem characteristics. The correct answer for each definition and task question was assigned a score of “1”, whereas the wrong answer was coded as “0”. The percentages of correctness score for total and each category of definition and task-specific questions were computed. The independent sample t-test and ANOVA were run to examine the differences in total and category-specific scores between student groups. Findings The findings revealed that students’ knowledge concerning the definition of infodemic and related terminologies and the categorization of COVID-19-related problematic social media posts was poor. There was no significant difference in correctness scores between student groups in terms of gender, age and study levels. Originality/value To the best of the authors’ knowledge, this is the first time an effort was made to understand LIS students’ recognition and classification of problematic information. The findings can assist LIS departments in revising and improving the existing information literacy curriculum for students.

The Effect of Bleach Liquid and Household Cleaner on Surface Hardness and Roughness of Acrylic Base of Orthodontic Appliances

2021 ◽  
Author(s):  
Saeed Noorollahian ◽  
Farinaz Shirban ◽  
Vahid Mojiri
Keyword(s):  
Surface Roughness ◽  
Hydrochloric Acid ◽  
Sodium Hypochlorite ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Liquid Sodium ◽  
P Value ◽  
Orthodontic Appliances ◽  
Acrylic Resins ◽  
Significant Difference

Introduction: The daily use of orthodontic removable plates can interfere with the self-cleansing function of the mouth. Although various techniques have been proposed for cleaning removable orthodontic appliances, there is no consensus on the use of a safe method that preserves the physical properties of the appliance. This study aimed to investigate the effect of using hydrochloric acid (10%, for removal of mineral deposits) and sodium hypochlorite (5.25%, to remove organic matter and discolorations) on surface hardness and roughness of self-cure orthodontic acrylic resins. Materials & Methods: This cross-sectional laboratory study was conducted in the fall of 2017 at Isfahan University of Medical science and Isfahan University of Technology. In this study two orthodontic acrylic resins (Orthocryl® and Acropars®) were used. Eighty samples (12×10×3 mm) from each one were fabricated and divided into four groups (n = 20). Group 1: 15 minutes immersion in household cleaner liquid (Hydrochloric acid, 10%) followed by15 minutes immersion in household bleach liquid (Sodium Hypochlorite, 5.25%). In group 2, immersions were repeated just like group two times and in group 3, were done three times. Group 4 was as control and had no immersion. The surface hardness and roughness of samples were measured. Data were analyzed with Two Way ANOVA and the significance level was set at 0.05. Results: The number of immersion procedures did not significantly affect the surface hardness (p value = 0.958) and surface roughness (p value = 0.657) in the different study groups. There was no significant difference in the surface hardness between the two acrylic resin brands (p value = 0.077); however, Acropars acrylic resin samples exhibited significantly higher surface roughness compared to the Orthocryl acrylic resin samples(p value < 0.001). Conclusion: 15 minutes of immersion in 10% HCl, followed by 15 minutes of immersion in 5.25% NaOCl and repetition of the procedure three times did not significantly affect the surface hardness and roughness of self-cured acrylic resins.

Abstract 255: A Fibroblast Population Shares A Developmental Origin With Cardiovascular Lineages

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Sara Ranjbarvaziri ◽  
Shah Ali ◽  
Mahmood Talkhabi ◽  
Peng Zhao ◽  
Young-Jae Nam ◽  
...  
Keyword(s):  
Heart Development ◽  
Cardiac Fibroblasts ◽  
Immunohistochemical Analysis ◽  
Cell Types ◽  
Mouse Heart ◽  
Developmental Potential ◽  
Reporter Mice ◽  
Significant Difference ◽  
Definition Of

Rationale: The traditional definition of “cardiovascular” lineages describes the eponymous cell types - cardiomyoctes, endothelial cells, and smooth muscle cells - that arise from a common mesodermal progenitor cell during heart development. Fibroblasts are an abundant mesenchymal population in the mammalian heart which may have multiple, discrete developmental origins. Mesp1 represents the earliest marker of cardiovascular progenitors, contributing to the majority of cardiac lineages. To date no link between Mesp1 and fibroblast generation has been reported. Objective: We hypothesized progenitor cells expressing Mesp1 can also give rise to cardiac fibroblasts during heart development. Methods and Results: We generated Mesp1cre/+;R26RmTmG reporter mice where Cre-mediated recombination results in GFP activation in all Mesp1 expressing cells and their progeny. To explore their developmental potential, we isolated GFP+ cells from E7.5 Mesp1cre/+;R26RmTmG mouse. In vitro culture and transplantation studies into SCID mouse kidney capsule as wells as chick embryos showed fibroblastic adoption. Results showed that at E9.5 Mesp1+ and Mesp1- progenitors contributed to the proepicardium organ and later at E11.5 they formed epicardium. Analysis of adult hearts demonstrated that the majority of cardiac fibroblasts are derived from Mesp1 expressing cells. Immunohistochemical analysis of heart sections demonstrated expression of fibroblast markers (including DDR2, PDGFRα and Col1) in cells derived from both Mesp1+ and Mesp1- progenitors. Additionally, we investigated whether the two distinct fibroblast populations have different potency towards reprogramming to cardiomyocytes. Results showed no significant difference between Mesp1 and non-Mesp1 isolated fibroblasts to convert to cardiomyocyte fate. Conclusions: Our data demonstrates that cardiovascular progenitors expressing Mesp1 contribute to the proepicardium. These cells, as cardiovascular progenitors, also give rise to the highest portion of cardiac fibroblasts in the mouse heart.

IMMERSION OF HEAT POLYMERIZED ACRYLIC RESIN DENTAL BASE IN ARAK BALI AGAINST SURFACE ROUGHNESS

2021 ◽  
Vol 17 (1) ◽  
pp. 22-26
Author(s):  
Kadek Ayu Wirayuni ◽  
◽  
I Made Hendri Dwi Saputra ◽  
Keyword(s):  
Surface Roughness ◽  
Acrylic Resin ◽  
Control Group ◽  
Surface Strength ◽  
Denture Base ◽  
A Value ◽  
Removable Denture ◽  
Significant Difference ◽  
Post Test ◽  
Oral Tissue

Introduction: The denture base is the part of the removable denture that is supported by good adaptation to the underlying oral tissue. Most of the denture bases are made of acrylic or polymethyl methacrylate resin, better known as PMMA. However, the acrylic resin also has disadvantages such as easily broken and absorbs liquids both water and chemicals. The chemical absorption like alcohol, ethanol, and some drinks that contain acidic materials will chemically be induced with acrylic resin and settle in the pores of the acrylic resin. The chemical damage or defect creates roughness on the surface of the acrylic resin which can cause cracking or crazing and a decrease in surface strength and hardness. Materials and Methods: The method used in this research was a laboratory experimental design with a post-test-only control group using 12 samples consisting of 2 different types of samples by measuring the surface roughness of the acrylic resin after immersing the sample with a predetermined time. Results and Discussions: One-way ANOVA test results showed a significant difference in surface roughness after the samples immersion with a value of p = 0.006 (p <0.05). Conclusions: Based on this research, can be concluded that there is an increase in the surface roughness of the heated polymerized acrylic resin for 3 hours and 4 hours of immersion. The longer the heated polymerized acrylic resin is soaked in arak hence the level of surface roughness increases.

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