Superabsorbent polymer: application in natural rubber for making rubber roofing sheets

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Doaa Samir Mahmoud ◽  
Medhat Lotfy Tawfic ◽  
Abdel Gawad Rabie ◽  
Salwa H. El-Sabbagh
Keyword(s):  
Natural Rubber ◽  
Low Cost ◽  
Bulk Polymerization ◽  
Gravimetric Analysis ◽  
Content Type ◽  
Gel Fraction ◽  
Cross Linker ◽  
Hot Weather ◽  
And Performance ◽  
Polymer Application

Purpose The purpose of this paper is to prepare superabsorbent polymers (SAPs) based on acrylic acid, which is considered hygroscopic material to incorporate in rubber formulation, which results in producing moisten rubber that is used as roofing sheets. Design/methodology/approach SAPs were synthesized via free radical bulk polymerization technique using different content of cross-linker N, N'-methylenebisacrylamide and potassium persulfate. Differential scanning calorimeter, thermal gravimetric analysis, Fourier transform infrared spectroscopy and transmission electron microscopy were used to characterize SAPs and confirmed the formation of cross-linked hydrogel structure. The water absorbency and the gel fraction for sodium polyacrylate (NaPA) were investigated. Then, the influence of obtained NaPA on the swelling behavior of the prepared natural rubber (NR) compound has been discussed. Findings Absorption characteristics and gel fraction of NaPA were found to depend on the content of the cross-linker in the system. SAPs are used to improve the absorbance behavior and performance of the NR to produce, roofing sheets using in hot weather. The morphology of the obtained rubber compound was well-explained by using a scanning electron microscope. Research limitations/implications The research provides a simple way to produce moisten rubber that can be used as a roofing sheet to overcome warm weather. Originality/value Moisten rubber roofing sheets provide a low-cost option in many developing countries with hot climates, and thus, help save the environment from global warming.

Design of symmetrical half-bridge converter with a series coupling capacitor

2020 ◽  
Vol 17 (5) ◽  
pp. 609-620
Author(s):  
Ruchi Rashmi ◽  
Shweta Jagtap
Keyword(s):  
Low Cost ◽  
Control Mode ◽  
Variable Load ◽  
Content Type ◽  
Symmetrical Mode ◽  
Coupling Capacitor ◽  
Switched Mode Power Supply ◽  
And Performance ◽  
Asymmetrical Mode ◽  
Voltage Control Mode

Purpose With the advancement of technology, size, cost, and losses of the switched mode power supply (SMPS) have been decreasing. However, due to the high frequency switching, design of magnetic drives and isolation circuits are becoming a crucial factor in SMPS. This paper presents design criteria, procedure and implementation of AC-DC half bridge (HB) converter with lower cost, smaller size and lower voltage stress on the power switch. Design/Methodology/approach The HB converter is designed in a symmetrical mode with a series coupling capacitor. Isolated power supplies are used for the converter and control circuit. Further, a transformer based isolated gate driver is used to drive both MOSFETs. The control IC works in voltage control mode to regulate voltage by controlling the duty cycle of the MOSFETs. Findings Control characteristics and performance of the HB converter is simulated using the MATLAB software and prototype of 170 W HB converter is built to validate the analytical results under variable load current and source voltage. The power quality and variation of load voltage at 2 A, 5 A, 7 A are reported. Originality/value This paper presents the design of a low-cost HB converter in a symmetrical mode which saves the additional cost of symmetric correction circuit normally required in asymmetrical mode design. This paper also focuses on the selection of primary and secondary side switch, series coupling capacitor, commuting diode, isolated drive and charge equalizer resistor.

scholarly journals Impact of mission requirements on the design of low observable UCAV configurations

2019 ◽  
Vol 91 (10) ◽  
pp. 1295-1307
Author(s):  
Eduardo Sepulveda Palacios ◽  
Howard Smith
Keyword(s):  
Low Cost ◽  
Leading Edge ◽  
Aircraft Design ◽  
Considerable Proportion ◽  
Design Environment ◽  
Sweep Angle ◽  
Content Type ◽  
Aerial Warfare ◽  
And Performance ◽  
Excess Power

Purpose The purpose of this paper is to characterise the effects of mission and performance parameters on the design space of low observable subsonic unmanned combat aerial vehicles (UCAVs) operating in typical Hi-Lo-Hi ground strike missions. Design/methodology/approach Conceptual design methodologies appropriate to low observable, tailless UCAVs have been integrated into a multidisciplinary aircraft design environment, GENUS, developed at Cranfield University’s aircraft design group. A basic Hi-Lo-Hi mission is designed and a baseline configuration is established through the GENUS framework. Subsequently, an evolutionary optimiser and a robust gradient-based optimiser are used to obtain convergent design solutions for various leading edge sweep angles, mission ranges, cruise Mach numbers and other operational constraints. Findings The results indicate that performance constraints, specifically in the form of specific excess power (SEP), have a large influence on the overall sizing of subsonic tailless UCAVs. This requirement drives the engine sizing, which represents a considerable proportion of the empty and gross mass of the vehicle. Cruise Mach number studies show that no significant advantages exist for operating at low speeds while maintaining performance requirements consistent with combat missions. There is a drastic increase in the vehicle’s mass and thrust requirements for flight speeds above Mach 0.8, with low sweep configurations showing a more pronounced effect. Increases in the range are not overly dependent on the leading edge sweep angle. Top-level radar cross section (RCS) results also favour configurations with higher leading edge sweep angles, especially from the nose-on aspect. Finally, research and development costs are shown to be directly linked to engine size. Originality/value This research shows the use of an integrated aircraft design environment that incorporates aerodynamics, performance, packaging and low observability aspects into the optimisation loop. Through this methodology, this study supports the efforts towards characterising and establishing alternate visions of the future of aerial warfare through the use of low cost, survivable unmanned platforms in network-centric cooperative tasks.

Assessment on the Synthesis and Performance of Low-Cost Chitosan-Coated Natural Zeolite Adsorbent for Post-Combustion Carbon Dioxide Capture

2018 ◽  
Vol 775 ◽  
pp. 383-389
Author(s):  
Dominique Jan Bacalso Tan ◽  
Bryan B. Pajarito
Keyword(s):  
Carbon Dioxide ◽  
Natural Zeolite ◽  
Carbon Dioxide Capture ◽  
Low Cost ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Zeolite Adsorbent ◽  
And Performance ◽  
Adsorption Desorption ◽  
Good Retention

An adsorbent for post-combustion carbon dioxide capture was prepared using low-cost and sustainable natural zeolite coated with chitosan. An optimum adsorbent was identified from 3 levels of particle size of natural zeolite and 10 levels of chitosan loading. The optimum adsorbent was characterized using infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis and differential scanning calorimetry. The chemical and thermal properties of the adsorbent indicated successful coating of chitosan on natural zeolite. The adsorbent registered competitive dynamic adsorption capacity of 0.81 mmol g-1 with good retention, at least, up to 5 adsorption-desorption cycles.

scholarly journals New water-based flexographic ink based on new ter-polymer nano-particles as eco-friendly binders – Part II

2020 ◽  
Vol 49 (6) ◽  
pp. 473-482
Author(s):  
H. Abd El-Wahab ◽  
G.A. Meligi ◽  
M.G. Hassaan ◽  
L. Lin
Keyword(s):  
Water Resistance ◽  
Low Cost ◽  
Thermo Gravimetric Analysis ◽  
Gel Permeation Chromatography ◽  
Nano Particles ◽  
Gravimetric Analysis ◽  
Adhesion Properties ◽  
Content Type ◽  
Low Viscosity ◽  
Water Based

Purpose The purpose of this study is to prepare, characterise and evaluate nano-emulsions of ter-polymers of various compositions as eco-friendly binders for flexographic ink industry. Design/methodology/approach Various nano-emulsions of ter-polymers were prepared based on Vinyl acetate, Vinyl Versatate, butyl acrylate, acrylic acid and acrylamide monomers by means of a conventional seeded emulsion polymerisation technique, using K2S2O8 as the initiator. The characterisation of the prepared emulsions was performed using Fourier transform infrared, thermo-gravimetric analysis, gel permeation chromatography and transmission electron microscopy. A selection of co-polymers and ter-polymers were formulated with pigments and additional ingredients, as water-based flexographic inks. The inks were characterised for their rheological properties, pH, degree of dispersion, water-resistance and colour density. Findings It was found that the low viscosity of the prepared polymers may reduce the film thickness of the flexographic inks and may also increase the spreading of the ink on the surface. As a result, stable modified poly acrylate-based latex with improved physico-mechanical properties was obtained. The prepared latexes showed improved properties such as enhanced thermal stability and better water resistance. The effect of the emulsifier type on the properties of the resulting emulsion latexes and their corresponding films were investigated. Also, as the hydrophobic monomer increases, so does the colour density and increasing the binder ratio enhances the gloss values. The improving in gloss values were obtained and provide excellent adhesion properties for both the pigment particles and the base paper. Research limitations/implications The study focusses on the preparation of new water-based ter-polymer nano-particles and their use as eco-friendly binders for flexographic ink industry. Ink formulations based on other different type emulsion polymers could also be studied to assess the applicability of the ink formulation system found for other binders. Practical implications The ink formulations developed could find use in industrial-scale printing. Originality/value Eco-friendly environment and low-cost ink formulations for printing on paper substrates are novel.

Mechanical, morphological, flamability and thermal properties of artificial wood plastic

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Emad S. Shafik ◽  
Medhat L. Tawfic ◽  
Adel F. Younan
Keyword(s):  
Maleic Anhydride ◽  
Flame Retardant ◽  
Coupling Agent ◽  
Low Cost ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Wide Range ◽  
Efficient Coupling ◽  
Analytical Tools

Purpose The purpose of this study is to manufacture composites from sawdust and polymer high-density polyethylene (HDPE) with different loading from alum as natural and cheap flame retardant and subsequently characterized using standard analytical tools. Design/methodology/approach Artificial wood plastic composites (WPCs) were prepared by mixing HDPE with sawdust as a filler with constant ratio (2:1) using hot press. Polyethylene-graft-maleic anhydride (PE-g-MAH) used as a coupling agent between two parents of the composites with different ratios (2.5, 5, 7 and 10). Alum as a flame retardant was incorporated into HDPE with 5 phr polyethylene grafted with maleic anhydride (PE-g-MAH) with different ratios (10, 15 and 20). Flame retardant efficiency was investigated using differential scanning calorimetry, thermal gravimetric analysis and the technique of ASTM E162. Findings The results revealed that the composite containing 5 phr from (PE-g-MAH) exhibited higher mechanical properties and this proved that (PE-g-MAH) act as an efficient coupling agent using the aforementioned ratio. The results also revealed that incorporation of alum as a flame retardant increased the thermal stability of the composites. Originality/value Artificial WPCs are ecofriendly materials with a wide range of applications in the constructions field. Moreover, they have high mechanical and physical properties with low cost. Evaluate alum as a natural and cheap flame retardant.

scholarly journals Service fitness ladders: improving business performance in low cost and differentiated markets

2017 ◽  
Vol 37 (10) ◽  
pp. 1266-1303 ◽  
Author(s):  
Alex Hill ◽  
Richard Cuthbertson ◽  
Benjamin Laker ◽  
Steve Brown
Keyword(s):  
Business Performance ◽  
Low Cost ◽  
Differentiated Services ◽  
Business Strategies ◽  
Direct Result ◽  
Content Type ◽  
Strategic Fit ◽  
Market Needs ◽  
And Performance ◽  
The Impact

Purpose The purpose of this paper is to present 13 propositions about how internal strategic fit (often referred to as fit) impacts the business performance of low cost and differentiated services. It then uses these relationships to develop two “fitness ladder” frameworks to help practitioners understand how to improve fit given their business strategy (low cost or differentiation) and performance objectives (operational, financial or competitiveness). Design/methodology/approach In total, 11 strategic business units were studied that perform differently and provide a range of low cost and differentiated services to understand how changes in internal strategic fit impacted business performance over a 7 year period. Findings The findings suggest aligning systems with market needs does not improve performance. Instead, firms serving low cost markets should first focus managers’ attention on processes and centralise resources around key processes, before reducing process flexibility and automate as many steps as possible to develop a low cost capability that is difficult to imitate. By contrast, firms serving differentiated markets should first focus managers’ attention on customers and then locate resources near them, before increasing customer contact with their processes and making them more flexible so they can develop customer knowledge, relationships and services that are difficult to imitate. Research limitations/implications Some significant factors may not have been considered as the study only looked at the impact of 14 internal strategic fit variables on 7 performance variables. Also, the performance changes may not be a direct result of the strategic fit improvements identified and may not generalise to other service organisations, settings and environments. Practical implications The strategic fit-performance relationships identified and the “fitness ladder” frameworks developed can be used by organisations to make decisions about how best to improve fit given their different market needs, business strategies and performance objectives. Originality/value The findings offer more clarity than previous research about how internal fit impacts business performance for low cost and differentiated services.

Pencil-on-paper flexible electronics for daily sensing applications

Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 189-195 ◽  
Author(s):  
Yan Liu ◽  
Hai Wang ◽  
Wei Zhao ◽  
Min Zhang ◽  
Hongbo Qin
Keyword(s):  
Flexible Electronics ◽  
Low Cost ◽  
Daily Activities ◽  
Content Type ◽  
Practical Applications ◽  
Sensing Applications ◽  
Rapid Fabrication ◽  
Temporary Solution ◽  
Finger Motion ◽  
And Performance

Purpose Inspired by the development of eco-friendly flexible electronics, this paper aims to present a series of paper-based electronics drawn by pencils, which can be used as favorable sensing elements in daily life. Design/methodology/approach Pencil traces are deposited on the porous surface of Xerox paper by the mechanical exfoliation during writing process, which can be used as basic components to construct functional electronics for daily sensing applications. By changing pencil grade, the obtained traces can work as conductive wires, electrodes, resistors and piezoresistive gauges. Findings The experimental results confirm their practical applications in sensing several daily activities, including finger motion, touching and the temperature of water in paper cup. Moreover, the used electronics can be easily handled and recycled. Research limitations/implications The shortage in functionality, reliability and performance consistency induced by manual operation is an evident challenge, which makes the pencil-on-paper devices more suitable to work as a temporary solution to satisfying the demands from emergency circumstances. Originality/value The pencil-on-paper devices, motivated by the electroconductibility and piezoresistivity of pencil trace, can be explored as sensing prototypes in detecting daily activities. Meantime, their advances in easy accessibility, rapid fabrication, low cost and eco-fitness endow them excellent capacity of meeting the “on-site, real-time” demands.

International backpackers' experiences of precarious visa-contingent farmwork

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chris Kossen ◽  
Nicole McDonald ◽  
Peter McIlveen
Keyword(s):  
Low Cost ◽  
Job Demands ◽  
Job Resources ◽  
Personal Resources ◽  
Work Experiences ◽  
Structured Interviews ◽  
Content Type ◽  
Agricultural Industry ◽  
And Performance ◽  
Emic Perspective

PurposeAustralia's agricultural industry has become highly dependent on young low-cost, overseas “working holiday” visa workers known as “backpackers”, who are notoriously subject to exploitative workplace practices. This study aimed to explore backpackers' experiences in terms of how job demands, job resources and personal resources influence their appraisals of working in agriculture.Design/methodology/approachIn-depth semi-structured interviews were used to explore the work experiences of N = 21 backpackers employed under the Australian Working Holiday visa (subclass 417). Data were analyzed by thematic analysis and organized in terms of job demands and resources.FindingsThis study revealed job demands commonly experienced by agricultural backpacker workers (e.g. precarity, physically strenuous work, low pay), and job resources (e.g. adequate training, feedback) and personal resources (e.g. attitude, language) that buffer the demands. The findings indicate that backpackers' appraisals of their experiences and performance decline when demands outweigh resources.Originality/valueThis study offers an emic perspective on the work of an understudied segment of the agricultural workforce. The findings have implications for improving work practices and policies aimed at attracting and retaining this important labor source in the future.

Composites of styrene butadiene rubber/modified clay: mechanical, dielectric and morphological properties

2017 ◽  
Vol 46 (3) ◽  
pp. 161-171 ◽  
Author(s):  
Salwa H. El-Sabbagh ◽  
Doaa Samir Mahmoud ◽  
Nivin M. Ahmed ◽  
A.A. Ward ◽  
Magdy Wadid Sabaa
Keyword(s):  
Tensile Strength ◽  
Low Cost ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Gravimetric Analysis ◽  
Scanning Electron Micrographs ◽  
Butadiene Rubber ◽  
Content Type ◽  
Modified Clay ◽  
Styrene Butadiene

Purpose This paper aims to study the role of organobentonite (OB) as a filler to improve the mechanical strength of styrene butadiene rubber (SBR). Organoclay was first prepared by modifying bentonite with different concentrations of N-cetyl-N, N, N-triethyl ammonium bromide. A series of SBR composites reinforced with OB were prepared using master-batch method. Design/methodology/approach The curing characteristics, mechanical properties, thermal behavior, dielectric properties and morphology of SBR/OB composites were investigated. Findings The elastic modulus and tensile strength of composites were increased by inclusion of OB, while the elongation at break was decreased, due to the increase in the degree of cross-linking density. Thermal gravimetric analysis revealed an improvement in the thermal stability of the composite containing 0.5 cation exchange capacity (CEC) OB, while the scanning electron micrographs confirmed more homogenous distribution of 0.5CEC OB in the rubber matrix. Also, SBR/0.5CEC OB showed low relative permittivity and electrical insulating properties. Research limitations/implications Bentonite has been recognized as a potentially useful filler in polymer matrix composites because of their high swelling capacity and plate morphology. Practical implications OB improves the cured rubber by increasing the tensile strength and the stiffness of the vulcanizate. Social implications Using cheap clay in rubber industry lead to production of low cost products with high efficiency. Originality/value The clay represents a convenient source because of their environmental compatibility. The low cost and easy availability make the modified clay used as fillers in rubber matrices, and the resultant composites can be applied in variety industrial of applications such as automobile industries, shoe outsoles, packaging materials and construction engineering.

Synthesis of nanosized mixed metal oxides heat and corrosion resistant pigments: CaMnO3, Ca2Cr2O5 and CaSb2O6

2015 ◽  
Vol 44 (6) ◽  
pp. 379-385 ◽  
Author(s):  
Osama A. G. Wahba ◽  
Ali M. Hassan ◽  
H. Abd El-wahab ◽  
A. Mohy-Eldin ◽  
A.M. Naser ◽  
...  
Keyword(s):  
Low Cost ◽  
Chemical Properties ◽  
Mixed Metal Oxide ◽  
Corrosion Resistant ◽  
Content Type ◽  
Mixed Metal ◽  
Nanosized Materials ◽  
Physico Chemical ◽  
And Performance ◽  
Co Precipitation

Purpose – The purpose of this paper is to investigate the synthesis of calcium-based group of mixed metal oxide (MMO) pigments. The evaluation of these pigments as heat and corrosion resistant was also explored. Design/methodology/approach – Two simple synthesis techniques, namely, co-precipitation and solid-state calcination method, were used to synthesise nanosized MMO pigments. And then the physico-chemical requirements according to standards for the synthesised pigments are investigated. Findings – The prepared MMO pigments were mainly in the single phase double oxide forms. The prepared oxides exhibited good heat (up to 600°C) and corrosion resistance properties (in 5 per cent NaCl for 500 h). Research limitations/implications – This paper investigates the physico-chemical properties of synthesised calcium-based group of MMO pigments. And then evaluate it as heat and corrosion resistant paints. The simple techniques used for synthesis of nanosized MMO pigments will significantly improve the research and development of pigments’ structure and performance. Practical implications – Calcium-based MMO pigments can be used as heat and corrosion resistant pigments. The easy synthesis of the mixed oxide pigments will open the door for further vital special industrial uses and applications. Originality/value – Low cost, simple techniques and using naturally abundant material can be used for mass production of some other low-cost nanosized materials.

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