12 research outputs found
Measuring Methods of Acoustic Properties and Influence of Physical Parameters on Natural Fibers: A Review
No full textNowadays, the world becomes more contaminated due to various factors such as pollution, global warming and unhealthy human practices. In this review paper, noise pollution is taken into major concern which affects quality of human life. Many researchers had attempted many studies to optimize the sound-absorbing capacity of natural fibers and to replace use of non-biodegradable synthetic sound barriers. This review research also focuses on the measurement of acoustic absorption coefficient (AAC) through various analytical such as Delany–Bazley, Garai–Pompoli and Biot–Allard method and experimental approaches such as impedance tube, reverberation room and environment anonymous (EA) noise. In addition to that, the influence of physical parameters such as fibrous material’s thickness, density and porosity are also reviewed. It was found that most of the reviewer used two microphone impedance test tubes for determining absorption coefficient (α) of natural fiber-reinforced laminates. The more denser, thicker and porous materials shows better absorption rate than less denser, thicker and porous materials due to its high polymerization blending. Finally, these measuring methods are used to enhance the properties such as absorbing and reflecting in applications like sound recording room, acoustic baffles, damping sheets, barrier decoupler, etc
Fabrication and Characterization of Partial Bio-nano-silica Inclusion in Fibre-Reinforced Concrete for High-performance Applications
No full textUltra-high-performance fibre-reinforced concrete (UHPFRC) is a specialized type of concrete (to create a very dense matrix) that is used for both new construction and renovation projects in order to improve the lifespan of structures. Researchers analyse and evaluate only the microstructure, porosity, and fresh and hardened concrete properties of UHPFRC but limited their exploration on the reduction of the mechanical properties of UHPFRC due to the presence of metallic particles and micro-fractures that occur during the generation of hydrogen. Hence, the present study aims to eliminate the existing problem by hybridization approach (mixing of bio-nano-silica (nS) and polypropylene) with different percentages to further improve the strength properties of UHPFRC. The result showed that the compressive strength is increased by 15.5% compared to traditional concrete due to the filling ratio of nS in the pores of the concrete; in addition, the fibre’s surface and roughness also contributed to the strength enhancement
Glass Fiber Hybrid Polymer Composites
No full textDuring last few decades, the hybrid composites emerged from natural fiber has brought incontestable advantages over synthetic materials. The environmental impact such as toxicity, nonbiodegradable garbage, and noise pollution has led to the identification of new class of fibers and also subsequent failure in critical stiffness and weight sensitivities of fiber-reinforced polymers has initiated magnification of mechanical toughness. In this present paper, fiber-reinforced composite materials are made with Camellia sinensis–Ananas comosus hybridized by glass fiber and epoxy resin matrix. The amalgamated laminates were forged by a compression molding process with the composition of 40% wt. of reinforcing fiber and 60% wt. of epoxy matrix in a constant proportion. A hydrophilic content present inside natural fibers are alkalized by 5% of NaOH to modify as hydrophobic nature for intensifying bonding between fiber and matrix. These hybridized fibers are mechanically, chemically, morphologically, and acoustically analyzed to meet the requirements of mechanical and sound proofing properties. The results shows that 25% wt. fraction of Camellia sinensis amalgamate with unidirectional fiber shows better average acoustical absorption coefficient (AAC) of 0.46 at 2000–6300 Hz frequency range and compared with existing material to establish the potential of using it in sound-proofing acoustical applications such as architectural acoustics, sound recording and reproduction room, noise barrier walls, loudspeaker design, etc
Acoustical Analysis and Drilling Process Optimization of Camellia Sinensis / Ananas Comosus / GFRP / Epoxy Composites by TOPSIS for Indoor Applications
No full textCamellia Sinensis/Ananas Comosus/GFRP/Epoxy Polymer composites are widely accepted to be a better material for indoor sound damping. It has a series of challenges, like force cuts on the drilling of these composites. The focus is to drill on hybrid laminates by changing the cutting conditions like the speed and feed and the selection of optimum machining process parameters. Nine experimental cycles have been performed, and five various attributes were analyzed, for example, torque, tangential force, thrust force, and also the factor of delamination (Enter & Exit). This study shows a sequential parameter selection for the drilling machining process. Using Multi-attribute optimization, order preference and optimum drilling machining process parameters are selected by the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). From the TOPSIS analysis, the best suitable optimum drilling conditions for hybrid laminates are chosen as 600 rpm and 0.02 m/min for cutting speed and feed rate, respectively
Preparation, Characteristics, and Application of Biopolymer Materials Reinforced with Lignocellulosic Fibres
No full textVarious environmental concerns motivate scientists and researchers to look out for unique new materials in science and technology. In order to address the demand for polymeric materials with partial biodegradability, the usage of lignocellulosic fibre in the polymer matrix has risen. Lignocellulosic fibres are a cheap, easily renewable resource that is readily available in all regions. Cellulosic plant fibres also have a plethora of possibilities for use in polymer reinforcement because of their properties. Many researchers put their effort into developing a natural polymer with better mechanical properties and thermal stability using nanotechnology and the use of natural polymers to make its composites with lignocellulosic fibres. This study provides a review of the biodegradable composite market, processing methods, matrix-reinforcement phases, morphology, and characteristic improvements. In addition, it provides a concise summary of the findings of significant research on natural fibre polymer composites (NFRCs) that have been published. Indeed, a noticeably brief discussion is provided on the significant issues faced during composite extraction as well as the challenges encountered during the machining. Recent developments in the study of lignocellulosic fibre composites or NFRCs have demonstrated their enormous potential as structural elements in vehicles, aerospace structures, buildings, ballistics, soundproofing, and other structures
Mechanical and Acoustic Properties of Alkali-Treated Sansevieria ehrenbergii/Camellia sinensis Fiber–Reinforced Hybrid Epoxy Composites: Incorporation of Glass Fiber Hybridization
No full textExperimental Study on the Sound Absorption Properties of Finger Millet Straw, Darbha, and Ripe Bulrush Fibers
No full textNowadays, emerging noise pollution by external factors causes harmful diseases in human beings. The development of a bio-based filler or panel will help to eliminate some unwanted noise in working places and living rooms. This work aimed to develop an ecowaste fiber (leftover after harvesting)-based sound absorber and analyze its capabilities for sound absorption. The ecowaste fibers are collected by the gleaning process, i.e., the process of collecting leftovers from fields. The sound absorption capabilities of three natural fibers extracted from Eleusine coracana (Finger millet) straw, Desmostachya bipinnata (Darbha), and Typha domingensis (Ripe bulrush) plants are investigated in this study, both individually and in hybrid combinations. The sound absorption property mainly depends on factors such as porosity, flow resistivity, thickness, density, and tortuosity. Fiber length and fiber type play a significant role when fibers are arranged individually or in hybrid combinations. The stacking effect on the sound absorption coefficient of hybridized fiber arrangement was experimentally analyzed. The sound absorption coefficient (α) was found to be lower in the range of 1000 Hz–2500 Hz for all the combinations. As a homogenous fiber arrangement, the darbha fiber exhibited the better NRC (noise reduction coefficient) of 0.86 for 50 mm thickness among three different fibers and as a hybrid composition, ripe bulrush and darbha fibers exhibited NRC of 0.90 which is more capable of absorbing sound in the critical frequency range of 500 to 2000 Hz. These types of natural fiber fillers are highly capable of better sound absorbing and used in the applications such as classrooms, sound recording rooms, and theatres
Study of Wear, Stress and Vibration Characteristics of Silicon Carbide Tool Inserts and Nano Multi-Layered Titanium Nitride-Coated Cutting Tool Inserts in Turning of SS304 Steels
No full textCutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts
Flow accelerated preferential weld corrosion of X65 steel in brine
No full textPreferential weld corrosion (PWC) remains a major operational challenge that
jeopardizes the integrity of oil and gas production facilities. It is the selective
dissolution of metal associated with welds, such that the weld metal (WM) and / or the
adjacent heat-affected zone (HAZ) corrode rather than the parent metal (PM). Corrosion
inhibition is conventionally used to mitigate this problem however several indications
suggest that some corrosion inhibitors may increase PWC. Furthermore, it is not
possible to detect systems that are susceptible to PWC and or to understand the apparent
ineffectiveness of some corrosion inhibitors at high flow rates. Consequently, the aim of
this research is to assess the suitability of submerged jet impingement method to study
flow accelerated preferential weld corrosion, which is critical to safe and economic
operations of offshore oil and gas facilities.
In this research, a submerged jet-impingement flow loop was used to investigate
corrosion control of X65 steel weldment in flowing brine, saturated with carbon dioxide
at 1 bar, and containing a typical oilfield corrosion inhibitor. A novel jet-impingement
target was constructed from samples of parent material, heat affected zone and weld
metal, and subjected to flowing brine at velocities up to 10 ms-
1
, to give a range of
hydrodynamic conditions from stagnation to high turbulence. The galvanic currents
between the electrodes in each hydrodynamic zone were recorded using zero-resistance
ammeters and their self-corrosion rates were measured using the linear polarisation
technique. At low flow rates, the galvanic currents were small and in some cases the
weld metal and heat affected zone were partially protected by the sacrificial corrosion of
the parent material. However, at higher flow rates the galvanic currents increased but
some current reversals were observed, leading to accelerated corrosion of the weld
region. The most severe corrosion occurred when oxygen was deliberately admitted into
the flow loop to simulate typical oilfield conditions. The results are explained in terms
of the selective removal of the inhibitor film from different regions of the weldment at
high flow rates and the corrosion mechanism in the presence of oxygen is discussed
