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Article
Publication date: 1 March 2010

Beverly B. Ray and Cynthia Lee A. Pemberton

This study explored perspectives of secondary social studies teachers, who reported using live media broad-casts to engage students in an examination of terrorism on 9/11…

Abstract

This study explored perspectives of secondary social studies teachers, who reported using live media broad-casts to engage students in an examination of terrorism on 9/11. Specifically, this study queried these teachers’ perceptions of preparedness on 9/11 to engage it as a learning event. Respondents (N=29) in one Mid-Atlantic state who were teaching in secondary social studies classrooms on September 11, 2001 (9/11), were asked to reflect on their level of preparedness to adapt and implement real-time teaching to address unfolding events. A Wilcoxon Signed Ranks Test for matched pairs revealed that respondents’ current perceptions of self-efficacy to teach about an unfolding terrorist act were positively modified by their experiences teaching about terrorism on 9/11 [Z = -4.507, p <.001 (two tailed)]. Respondents reported gains in confidence to teach about terrorism because of their teaching experiences on 9/11. Results add to the small knowledge base on the topic, even as they highlight the need for further research on the classroom response to 9/11.

Article
Publication date: 31 May 2011

S. Sethi and B.C. Ray

The purpose of this paper is to analyze microstructural integrity at the interface and consequent implicating effect on mechanical behavior of fiber‐reinforced polymer composites.

Abstract

Purpose

The purpose of this paper is to analyze microstructural integrity at the interface and consequent implicating effect on mechanical behavior of fiber‐reinforced polymer composites.

Design/methodology/approach

In the light of Fourier transform infrared spectroscope (FTIR imaging) and temperature‐modulated differential scanning calorimeter, a sorption mechanism was established. Thermal spike and thermal shock treatment was carried out at 150 and 80°C, respectively. This suggested that fiber/matrix adhesion rests on the structure and properties of both the fiber and matrix in the region near the interface during the hygrothermal treatment.

Findings

The carbon surface was found to selectively absorb the tertiary amine catalyst and to modify the chemical state of the cured resin apparently through the effects of absorbed water. The higher values of glass transition temperature (Tg) resulted in longer immersion time and higher exposure temperature. Together, these techniques provide a comprehensive picture of chemical and physical changes at the interphase region. Thermal spike of hybrid composite at 150°C temperature might possibly improve the adhesion level at the interface. Whereas, in case of thermal shock treatment at 80°C the fall in inter‐laminar shear strength value at higher number of cycles. This degradation of the interface region has been monitored by scanning electron microscope analysis.

Originality/value

The reported data are based on experimental investigation.

Details

International Journal of Structural Integrity, vol. 2 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 12 July 2021

Kawaljit Singh Randhawa and Ashwin Patel

This paper aims to investigate the mechanical and thermal behavior, i.e. tensile strength, hardness, impact strength and glass transition temperatures of water-treated…

Abstract

Purpose

This paper aims to investigate the mechanical and thermal behavior, i.e. tensile strength, hardness, impact strength and glass transition temperatures of water-treated polyamide6/boric oxide (PA) composites.

Design/methodology/approach

The PA6 and PA6/boric oxide composites were exposed to an open environment and immersed in water for 15 days to analyze the effect of environmental humidity and frequent water immersion conditions on the composite’s mechanical and thermal properties. The tensile strength, elastic modulus, hardness and impact strength of materials were measured to identify the mechanical properties. The scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) characterizations were used to see the effect of humidity/water absorption on microstructure, crystallinity and glass transition temperatures.

Findings

The testing results revealed the loss in strength, elastic modulus and hardness, while the impact resistance was improved after exposure of materials to humidity/water. SEM images clearly show the formation of voids and XRD graphs revealed the loss in crystallinity after water immersion. The DSC plots of water immersed materials revealed the loss of glass transition temperatures up to 15°C.

Originality/value

The mechanical and thermal behavior of PA composites varies according to the surrounding atmosphere. Experiments were performed to investigate the influence of water treatment on the PA6/B2O3 composite’s mechanical and thermal properties. Water treatment resulted in the bonding between PA and water molecules, which generated voids in the materials. These voids generations are found the main reason for the low strength and hardness of water-treated materials.

Details

Pigment & Resin Technology, vol. 51 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 6 July 2010

G. Mishra, S.R. Mohapatra, P.R. Behera, B. Dash, U.K. Mohanty and B.C. Ray

The main objective of this experimental investigation is to assess the effect of thermal and cryogenic treatment on hygrothermally conditioned glass fibre reinforced epoxy…

Abstract

Purpose

The main objective of this experimental investigation is to assess the effect of thermal and cryogenic treatment on hygrothermally conditioned glass fibre reinforced epoxy matrix composites, and the impact on its mechanical properties with change in percentage of individual constituents of the laminates.

Design/methodology/approach

The present investigation is an attempt at evaluating the performance of the laminates subjected to different thermal and cryogenic treatments for varying time with prior hygrothermal treatment. The variability of hygrothermal exposure is in the range of 4‐64 h. Glass fibre reinforced plastics laminates with different weight fractions 0.50‐0.60 of fibre reenforcements were used. The ILSS, which is a matrix dominated was studied by three‐point bend test using INSTRON 1195 material testing machine.

Findings

The post‐hygrothermal treatments (both thermal and cryogenic exposures) resulted in an increase in the rate of desorption of moisture. It is noted that the hygrothermal treatment prior to the exposure to thermal or cryogenic conditioning is the major attribute to the variations in the ILSS values. The extent of demoisturisation of the hygrothermally conditioned composites due to a thermal or a cryogenic exposure is observed to be inversely related to its ILSS, independent of the fibre‐weight fractions. Also the ILSS is inversely related to the fibre‐weight fraction irrespective of the post‐hydrothermal treatment.

Originality/value

The reported data are based on experimental investigations.

Details

Aircraft Engineering and Aerospace Technology, vol. 82 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 19 September 2017

Puneet Kumar and J. Srinivas

The purpose of this paper is to perform a numerical analysis on the static and dynamic behaviors of beams made up of functionally graded carbon nanotube (FG-CNT…

Abstract

Purpose

The purpose of this paper is to perform a numerical analysis on the static and dynamic behaviors of beams made up of functionally graded carbon nanotube (FG-CNT) reinforced polymer and hybrid laminated composite containing the layers of carbon reinforced polymer with CNT. Conventional fibers have higher density as compared to carbon nanotubes (CNTs), thus insertion of FG-CNT reinforced polymer layer in fiber reinforced composite (FRC) structures makes them sustainable candidate for weight critical applications.

Design/methodology/approach

In this context, stress and strain formulations of a multi-layer composite system is determined with the help of Timoshenko hypothesis and then the principle of virtual work is employed to derive the governing equations of motion. Herein, extended rule of mixture and conventional micromechanics relations are used to evaluate the material properties of carbon nanotube reinforced composite (CNTRC) layer and FRC layer, respectively. A generalized eigenvalue problem is formulated using finite element approach and is solved for single layer FG-CNTRC beam and multi-layer laminated hybrid composite beam by a user-interactive MATLAB code.

Findings

First, the natural frequencies of FG-CNTRC beam are computed and compared with previously available results as well as with Ritz approximation outcomes. Further, free vibration, bending, and buckling analysis is carried out for FG-CNTRC beam to interpret the effect of different CNT volume fraction, number of walls in nanotube, distribution profiles, boundary conditions, and beam-slenderness ratios.

Originality/value

A free vibration analysis of hybrid laminated composite beam with two different layer stacking sequence is performed to present the advantages of hybrid laminated beam over the conventional FRC beam.

Details

Multidiscipline Modeling in Materials and Structures, vol. 13 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 1 March 2016

Katherine Assante Perrotta and Joseph R. Feinberg

College instructors are entering a new frontier of teaching in the 21st century. Millennial students are bringing to university classrooms different experiences regarding…

Abstract

College instructors are entering a new frontier of teaching in the 21st century. Millennial students are bringing to university classrooms different experiences regarding the ways they learn and engage in critical thinking. As online universities gain more popularity across the country, higher education institutions are offering more hybrid and distance-learning courses on the Internet match the demand for using technology for teaching and learning. This action research study evaluates how the Annenberg Media digital simulation The Constitutional Convention of 1787 effected student engagement in an undergraduate history course at a community college in a metropolitan region of the Southeast. Practical suggestions are provided for college level history instructors to adapt digital simulations for teaching curricular and content skills that foster critical thinking, digital literacy, and engaged learning.

Details

Social Studies Research and Practice, vol. 11 no. 1
Type: Research Article
ISSN: 1933-5415

Keywords

Content available
Book part
Publication date: 28 March 2017

Chandan Kumar Sadangi and Sanjay Mohapatra

Abstract

Details

Change Management for Organizations
Type: Book
ISBN: 978-1-78714-119-3

Book part
Publication date: 13 May 2019

Hasan Dinçer and Serhat Yüksel

The purpose of the study is to analyze the risk of violent conflict with the global conflict risk factors in the Middle East economies by using an integrated fuzzy…

Abstract

The purpose of the study is to analyze the risk of violent conflict with the global conflict risk factors in the Middle East economies by using an integrated fuzzy decision approach. For this purpose, five different dimensions and 24 different criteria are defined by analyzing similar studies in the literature. The dataset is borrowed from the European Commission, and experts appointed for the linguistic evaluation of each dimension and criterion. Additionally, fuzzy Decision Making Trial and Evaluation Laboratory (DEMATEL) methodology is used to weigh dimensions and criteria and Multi-objective Optimization on the basis of Ratio Analysis (MOORA) approach is considered to rank the countries with respect to the conflict risk. Social dimension was concluded to have the highest importance of the Global Conflict Risk Index. Moreover, Syria, Libya, and Saudi Arabia were identified as the countries that have high conflict risk. Because these countries have high risk of facing conflict in the future, it is strongly recommended that they should primarily focus on social factors in order to minimize this risk.

Details

The Impact of Global Terrorism on Economic and Political Development
Type: Book
ISBN: 978-1-78769-919-9

Keywords

Article
Publication date: 30 January 2007

B. Das, S.K. Sahu and B.C. Ray

The objective of the present work is to ascertain the failure modes under different loading speeds along with change in percentage of constituents of FRP composites.

Abstract

Purpose

The objective of the present work is to ascertain the failure modes under different loading speeds along with change in percentage of constituents of FRP composites.

Design/methodology/approach

This involves experimental investigation of FRP composites with woven roving fibers and matrix. Different types of composites, i.e. glass: epoxy, glass: polyester and (carbon+glass): epoxy are used in the investigation with change in percentage of constituents. The variability of fiber content of the composite is in the range of 0.55‐0.65 weight fractions. The matrix dominated property, like inter laminar shear strength (ILSS) has been studied by three point bend test using INSTRON 1195 material testing machine with increasing five cross head velocities.

Findings

The variation of ILSS of laminates of FRP composites is significant for low loading speed and is not so prominent for high speed. The variation of ILSS are observed to be dependent on the type and amount of constituents present in the composites. The laminates with carbon fiber shows higher ILSS than that of glass fiber composites. The laminates with epoxy matrix shows higher ILSS than polyester matrix composites for the same fiber. There is no significant variation of ILSS beyond loading speed 200 mm/min and this can be used for specifications of testing. Matrix resins such as polyester and epoxy are known to be highly rate sensitive. Carbon fiber are relatively rate independent and E‐glass fibers are rate sensitive. Woven roving carbon glass fiber reinforced polymer shows small rate dependence and woven roving glass fiber reinforced polymer shows significant rate sensitivity.

Originality/value

The findings are based on original experimental investigations in the laboratories of the institute and can be used for characterization of composites.

Details

Aircraft Engineering and Aerospace Technology, vol. 79 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 22 May 2009

A.K. Khan, B.C. Ray, J. Maiti and S.K. Dolui

The purpose of this paper is to study the effect of monomer composition in core‐shell latex prepared from co‐polymer of styrene‐butylacrylate (BA)‐methyl methacrylate…

Abstract

Purpose

The purpose of this paper is to study the effect of monomer composition in core‐shell latex prepared from co‐polymer of styrene‐butylacrylate (BA)‐methyl methacrylate (MMA) and their paint properties.

Design/methodology/approach

The core‐shell latex was prepared by a stepwise semi‐batch emulsion polymerisation. A set of dispersion was made with the different core‐shell compositions. The core phase consists of a copolymer of styrene‐BA‐acrylic acid (AA) and the shell phase consists of a copolymer of MMA‐AA. The properties of latex were determined by solid content, viscosity, pH and particle size. Subsequently, emulsion paint (PVC‐37 per cent and NVM‐53 per cent) was prepared using core‐shell latex. The paint properties were determined by block resistance, gloss, elongation at break, etc. The particle morphology was characterised with transmission electron microscope (TEM).

Findings

Core‐shell structure of latex was confirmed by TEM. The performance of core‐shell latex has been optimised and the best combination achieved with 25‐40 per cent of hard phase in core‐shell latex.

Research limitations/implications

Although the core‐shell structured latex was prepared from co‐polymer of styrene‐BA‐MMA monomer, the system could be extended with other monomers depending on the end use of surface coating.

Practical implications

The paint industry may use this method to improve paint properties.

Originality/value

The paper shows that, by use of core‐shell latex, it is possible to achieve high‐block resistance, hardness, elasticity and gloss.

Details

Pigment & Resin Technology, vol. 38 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

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