The MoS
2
nanoflakes can be a novel candidate as a solid lubricant in fabricating friction material for automotive brake-pad disc systems. In this paper, an investigation has been made to analyze the ...effect of MoS
2
nanoflakes on the mechanical and tribological behavior of the formulated copper-free low-metallic composite friction material. Three samples, namely S
1
, S
2,
and S
3,
have been fabricated containing different types of solid lubricant. Sample S
1
had a solid lubricant as graphite, while samples S
2
and S
3
had graphite mixed with solid lubricant MoS
2
with average flake sizes of 2 µm and 50 nm, respectively. Other components included steel, PAN, and aramid as reinforcing fibers; walnut powder, barium sulphate (BaSO
4
), and nitrile-butadiene rubber as fillers; phenolic resin as a binder; and FeO, Quartz, and MgO as abrasives. A pin-on-disc tribometer test (ASTM G-99) was conducted to carry out the wear test at a load of 60 N, sliding velocity of 2.09 m/s, and sliding distance of 6283 m at room temperature. A scanning electron microscope was used to study the micro-structural evolution of worn composite friction pin material. The results show that the nano-sized MoS
2
solid lubricant influences the structural integrity of the formulated composites, which governs the friction and wear behavior. The graphite and MoS
2
-based friction composites S
2
and S
3
perform better than the conventional friction material (S
1
) containing graphite in terms of physical–mechanical, thermal, and tribological properties. The specific wear rate of the S
1
sample is the highest (2.72 × 10
–5
mm
3
/Nm) followed by S
2
(1.84 × 10
–5
mm
3
/Nm) and S
3
(0.98 × 10
–5
mm
3
/Nm) respectively. The graphite and MoS
2
-based friction specimens S
2
and S
3
showed adequate coverage of friction plateaus, reducing wear and abrasion of the counter disc.
Graphical Abstract
In the current scenario, due to the high expectations and rapidly changing demands of the customers’, the majority of manufacturing sectors in developing nations now facing very tough to thrive. As ...this environment becomes more challenging, it is necessary to switch from conventional manufacturing systems to advanced manufacturing systems, such as CNC, FMS, HFMS, and CIM. This paper’s goal is to give researchers a foundation on which to choose proactive alternatives to CNC. This study’s objectives are to identify the elements that influence the manufacturing system and identify the most effective manufacturing system. For this purpose, different alternate technologies like flexible numerical control (FNC), The intelligent numerical control, open numerical control system, digital signal processor (DSP), and open-architecture CNC have been discussed in detail. The revised definition of an FMS, or FNC, proposed in this work gives room for the creation of more efficient systems and creates new avenues for research. Limitations of traditional FMS, design and working principle of DSP servo control technology, and other related alternate technologies to CNC in FMS have also been discussed in this research.
This work reports thermo-mechanical, thermo-gravimetric, thermal conductivity, and fracture toughness behavior of Cobalt particulates (0–2wt% @ step of 0.5%) reinforced Al 7075 alloy composites ...fabricated via a high vacuum casting method for gear materials. The experimentally evaluated results show that thermo-mechanical and thermo-gravimetric magnitudes improve with reinforcing phase content. The fracture toughness measured experimentally at various crack lengths of 1, 3, and 5 mm was found to be in the range of 1.69–4.07 MPa.m
1/2
and shows a rising trend with particulate content, while thermal conductivity (range 130–120 W/m°K) shows the diminishing trend. A theoretical model of both characteristics was proposed and validated with an error of ~ 4%.
In the present research work, organic hybrid friction composite materials based on synergistic binary and ternary fibrous combination of ceramic-organic fibers were designed and fabricated especially ...for automotive braking applications. It encompasses masterbatch of straight phenolic resin, barite, and graphite reinforced with aramid pulp, potassium titanate whiskers and aluminosilicate ceramic fiber amounting to 100% by weight. Fabrication was carried as per formulation design and as per standard industrial procedure using hot molding compression machine followed by post-curing and polishing of pad surface. Thereafter, specimens were characterized for their physical, thermal, mechanical and friction braking performance. The performance parameters (viz. frictional response, friction-fade, friction-recovery, wear, etc.) were evaluated on the Krauss friction testing machine following European Commission for Energy Regulation-90 (ECE R-90) regulations and (pulse velocity wave) PVW-3212 standard test protocol. In this work, thermal characteristics (i.e. DMA and TGA/DTG) of the investigated composites are discussed in details and an attempt has been made to correlate various thermophysical-mechanical characteristics and their possible influence on the braking tribology and wear performance.
The frothers of alcohol family (MIBC and Alpha-terpineol) were compared with polyglycol ethers (DF-1012) in terms of two phase characterization parameters like foamability, foam stability, surface ...activity and bubble size distribution. In this research, fundamental two phase frother characterization parameters were linked with three phase coal flotation behavior.
The frothers are found to have a major impact on bubble size. It seems that frothers not only prevent bubble coalescence, but also, affect the bubble break-up process. DF-1012 is more efficient in preventing bubble coalescence and provides more stable and viscous foams compare to MIBC and Alpha-terpineol. The least surface-active frother, MIBC, produces the finest bubbles and the largest bubbles are observed when the most surface-active frother DF-1012 is used. DF-1012 is showing parallel (loop and coil) orientation at the air–water interface. DF-1012 is showing maximum frothing performance (max. retention time) and foam stability (max. collapse time) at all pH. DF-1012, Alpha-terpineol and MIBC are insensitive to solution pH. Two phase frother characterization indices and observations are well correlating with three phase flotation performance indices like selectivity, kinetics and size wise flotation efficiency.
In this work, AA7075 ˗ SiC (0–8 wt.% @ step of 2%) / marble dust (8–0 wt.% @ step of 2%) / graphite (3 wt.%) hybrid alloy composites have been designed and fabricated via high vacuum casting method ...as per standard procedure, leading to five samples namely SM-08, SM-26, SM-44, SM-62, SM-80 respectively. Thereafter, possible synergistic impact of the complementary combination of SiC/marble dust reinforcing particulates on physical, mechanical, and sliding wear performance of hybrid alloy composites were investigated followed by surface morphology studies. Taguchi approach has been used for sliding wear parametric optimization and hybrid ENTROPY-VIKOR decision-making technique is used for ranking of material based on performance measures. It is observed that with the reinforcing phase the properties like wear performance, coefficient of friction, density, voids content, compressive strength, and impact strength of composites increases considerably while flexural strength diminishes. Thus, SM-62 alloy composite (having 6 wt.% SiC, and 2 wt.% marble dust) shows better improved overall performance relative to others.
This research paper describes the fabrication of different weight percentages of (0-2 wt-%) nickel powder-filled aluminium alloy composites by stir casting techniques under a controlled environment. ...The physical, mechanical and tribological analyses of the nickel powder-filled aluminium alloy (Al-7075 series) composites are studied experimentally. The void content, Vickers hardness, compressive strength and impact strength of the unfilled and particulate-filled alloy composites are increased with the increase in filler content, while flexural strength of the composites shows reverse in trend. At the end, sliding wear analysis is performed to assess the wear performance of the unfilled and particulate-filled alloy composites. It is also observed that 2 wt-% nickel powder-filled alloy composite exhibits higher wear resistance as compared to other alloy composites. Finally, the microstructure analysis of the worn out composites is observed through scanning electron microscope to comprehend the wear mechanism of the composites for gear material application.
This research work examines the physical, mechanical, thermal, thermo-mechanical, and dry sliding wear performance of hybrid waste flyash particulates (F-class; 0-20 wt% @ step of 5%) – Lapinus ...fibres (fixed 10 wt%) reinforced Polyamide 66 polymer composites fabricated using the twin screw extruder and injection moulding machine. This follows worn surface morphology to understand the prevailing wear mechanisms responsible for surface damage during sliding. Optimization of control parameters and identification of their order of significance in the dry sliding wear process is performed using Taguchi’s design of experiments and analysis of variance (ANOVA). Further, ranking optimization of the hybrid composite specimens based on their performance metrics is analysed using the hybrid AHP-R method. It has been observed that the hybrid composite specimens having 10 wt% flyash particulates optimize the overall performance metrics; therefore, it may be recommended to fabricate parts or components for industrial usage. It tends to have an experimental density of 1.18 g/cc, voids content of 7.11%, water absorption of 3.87%, tensile strength of 105.95 MPa, flexural strength of 144.86 MPa, Rockwell hardness of 58.12 HRM, fracture toughness of 4.11 MPa√m, Impact strength of 1.86 J, thermal conductivity of 1.08 W/mK, and specific wear rate of 1.12 × 10−3 mm3/Nm. This observation was attuned to the ranking analysis using the hybrid AHP-R method.
Summary
This paper focuses on automatic generation control (AGC) in deregulated environment for the multiarea interconnected power system. Each area consists of different kind of generating sources ...like thermal, hydro, and gas, each having different characteristics with physical constraint likes governor dead band and generation rate constraint. Loads are divided among different generator using the concept of economic load dispatch. The AC/DC links has been installed in all areas as well as unified power flow controller (UPFC) in tie lines to mitigate the effect of oscillation and to improve the system response. Thus, a more systematic and synchronized control of AGC with UPFC and AC/DC links has been proposed. Small signal stability of each area has been analyzed for finding out the oscillation states of the studied system. The proposed controller is optimized through Fruit Fly Algorithm, and its promising results reveal that the proposed controller is more efficient and effective in all different power transaction modes of restructured scenario.
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