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•Mn-based SCR catalysts with different CuO content were analyzed and tested over TiO2/CNTs composite support for NO conversion.•Effect of CuO and CNTs addition to Mn/Ti catalyst on ...H2O/SO2 resistance was investigated.•Test results depicted that addition of 5 wt% CuO was sufficient to achieve better NO conversion in the temperature regime of 150–350 °C.•Remarkable low temperature SCR activity was achieved with the addition of CuO to Mn/Ti-C catalyst.
A series of titania-carbon nanotubes (TiO2-CNTs) supported MnOx-CuO catalysts were prepared and investigated for NH3-SCR of NO at low temperature. It was observed that the addition of Cu and/or CNTs to Mn/TiO2 has a beneficial effect in improving the activity of the catalyst. In addition, the effect of Cu loading was also studied and found that the catalyst with 5 wt% Cu (Mn-Cu5/Ti-CNTs) exhibited the best NH3-SCR performance. Remarkably, the Mn-Cu5/Ti-CNTs showed excellent resistance to SO2/H2O in comparison to the Mn/TiO2 catalyst. The addition of CNTs has increased the specific surface area, total pore volume, and reduced the average pore size of the catalyst. Meanwhile, the Cu loading has enhanced the Mn4+ species and chemisorbed oxygen species on the surface of the catalyst. Besides, the incorporation of both Cu and CNTs have decreased the catalyst reduction temperature and increased the amount and strength of acidic sites on the catalyst. All these factors contributed to the superior NH3-SCR activity and SO2/H2O resistance of the catalyst.
Purpose
Finite element analysis is frequently used for lumbar spine biomechanical analysis. The primary scope of this work is to illustrate, using finite element analysis, how the biomechanical ...behavior of the Transforaminal lumbar Interbody fusion (TLIF), along with a novel combination of the Interspinous process device (IPD) and pedicle screws, improves lumbar spine stability.
Methods
In this study, Unilateral Pedicle Screw Fixation (UPSF) and Bilateral Pedicle Screw Fixation (BPSF) were used. Four FE model was developed using ANSYS software, as follows: (1) Intact model; (2) TLIF with "U"-shaped Coflex-F IPD (UCF); (3) TLIF with Coflex-F and UPSF (UCF + UPSF); and (4) TLIF with Coflex-F and BPSF (UCF + BPSF). The intact model was subjected to four pure moments (10 Nm), and the results were validated with previous literature data. The intact model results correlated well with the literature data, and the model was validated. Three surgical models were subjected to 7.5 Nm four pure moments, Flexion (FL), Extension (ET), Lateral bending (LB), and Axial rotation (AR) and a 280N follower load.
Results
The surgical model results are compared with the intact model. The comprehensive analysis results show the UCF + BPSF surgical model gave a good advantage on range of motion, cage stress, Coflex-F stress, and endplate stress compared among the two models.
Conclusions
This study proposes that the UCF + BPSF system helps to reduce the stress on the implant and adjacent endplates and gives very good stability to the lumbar spine under the various static loading conditions.
•deNOx efficiency was more influenced by Zeolite catalysts than traditional catalysts (Vanadium, Manganese, Cerium, etc.) in the NH3-SCR activity.•Among zeolite catalysts, Cu-doped and Fe-doped ...zeolite catalysts exhibit excellent deNOx efficiency in lower and higher operating temperatures respectively.•The parameters such as GHSV, operating temperature window, and doping percentage exhibit the catalyst's performance for NOx in ammonia-selective catalytic reduction.
Emission plays a vital role in the pollution of air and influences various effects on the living beings in the environment, including significant health effects for living beings. Therefore, several emission control measures were implemented to achieve a pollution-free environment. Selective Catalytic Reduction (SCR) is one of the post-combustion technologies predominantly used in an internal combustion engine to reduce the percentage of oxides of Nitrogen (NOx) emissions in the exhaust gases. This review covers various types of catalysts used in SCR for the reduction of NOx emissions, such as metal-based catalysts (Vanadium, Manganese, Titanium, and Cerium) and zeolite-based catalysts, providing an insight into the performance along with the effects of characteristics behaviour of each catalyst such as GHSV, efficiency for various temperature window, percentage doping, and NOx conversion efficiency. The review concludes zeolite catalyst exhibits excellent deNOx efficiency, which 2 to 4 wt% doping of Cu shows deNOx around 95%, and doping of Fe widens the operating window temperature.
Hand-operated tools transmit a high magnitude of vibration exposure to the hand-arm system that causes occupational diseases. The health effects caused in various countries for the past years due to ...usage of hand tools are necessary to identify the occupational disorders. Researchers have conducted various studies on biological effects, hand-transmitted vibration exposure and biodynamic responses throughout the years. This article goes over each of these studies in detail, as well as identifying areas where more research is needed. The majority of studies deal with the following topics: general guidelines for hand-transmitted vibrations; assessment techniques of vibration exposure; hand-tool evaluation methods; influence of hand-tool design to overcome the biomechanical effects; and finite element modelling for quantifying vibration exposure. In response to this, understanding the biodynamic behaviour of the hand-arm system is useful for better ergonomic intervention in hand tools to reduce fatigue and increase comfort.
Non-automated tool handles transmit a large magnitude of vibration to operators' hands, causing discomfort and pain. Therefore, the need for a better handle design is a matter of prime concern to ...overcome musculoskeletal disorders such as hand-arm vibration syndrome.
This study aimed to examine the influence of handle shapes in reducing the transmission of hand-arm vibration.
Seven different handles were designed and fabricated using 3D printing technology at the SSN College of Engineering, with consideration for the anatomical shape of the hand. The frequency-weighted Root Mean Square (RMS) values of the vibration levels transmitted were recorded at the wrist of twelve subjects, unaffected by musculoskeletal disorders. Subjective ratings of vibration and comfort perception were measured using the Borg Scale of Perceived Exertion.
The total vibration value (ahv) of each of the six novel prototype handles (B-G) was compared to that of the reference handle denoted handle-A. The vibration reductions for handles B to G respectively were 0.542 m/s2 (14.59%), 0.481 m/s2 (12.95%), 0.351 m/s2 (9.45%), 0.270 m/s2 (7.27%), 0.407 m/s2 (10.96%) and 0.192 m/s2 (5.17%).
A significant level of vibration reduction was achieved by the prototype handles. Qualitative feedback from the study subjects suggests that they were not aware of the levels of vibration being transmitted to the hand with each handle.
This research work aims to study the performance of biochar-supported manganese-based catalysts for conversion of NOx in the selective catalytic reduction (SCR) process. Biochar, a high energy ...density solid generated from biomass pyrolysis, usually is combusted to provide extra heat to the pyrolysis process. Compared to other carbonaceous materials, biochar has a larger surface area, large surface functional groups and is more economically advantageous. An experimental and observational methodology was adopted in which biochar with activation temperatures of 500 °C, 600 °C, and 700 °C were used as additional catalytic support to the Manganese-based SCR catalyst. The prepared samples were analyzed by various techniques like X-ray diffraction, Scanning electron microscopy, X-ray photoelectron spectroscopy, NH
3
-Temperature-programmed desorption and H
2
-Temperature programmed reduction to study various parameters like crystallographic structure and crystal properties, chemical states and elemental composition, surface acidity, and reducibility of the catalyst. Upon adding biochar, it was observed that the pore volume increased by 150% and the surface area by 114%. Subsequently, catalytic activity tests were conducted on the effect of biochar on NOx removal, SO
2,
and H
2
O tolerance, and the optimum catalyst composition were found. Catalytic performance increases with the addition of biochar over all temperature ranges, with Mn/TiO
2
-Char
700
reaching a maximum NOx conversion rate of 90%, indicating that biochar is a viable alternative to existing catalytic supports.
Graphical Abstract
Composites reinforced with landfill waste materials have find the applications in engineering materials and they can lead to reduce the environmental pollutions. Waste tyre rubber, broken ceramic ...tiles and wood particles are creating the environmental hazard to the surroundings. In particular, the recycling of used tyre rubber is highly challenging, but it has very good property to absorb the energy. The reinforcement of rubber as single filler in composite has the limitations in processing and applications. Hence, the above waste materials are incorporated to prepare the composite in the present work. The fracture toughness and shear strength of composites were evaluated and compared with other combinations along with pure epoxy specimen. In order to find the application of composite in dynamic conditions the vibration analysis were done. The presents of rubber decreased the fracture toughness and at the same time the incorporation of ceramic largely improved the fracture toughness of epoxy composite. The shear strength of composites increased with the addition of ceramic and wood particles. But the rubber particle has the great influence on the damping behavior of ceramic base epoxy composites. The addition of ceramic with the epoxy increased the natural frequency and decreased the damping factor. This can be compensated by the inclusion of rubber with ceramic in epoxy resin matrix. 15 wt % addition of rubber with ceramic and epoxy increased the natural frequency of 18.52% and damping factor of 288% than 5 wt % of rubber with ceramic and epoxy. The natural frequency and damping factor of ceramic and rubber based epoxy composite have the highest amount of all combinations and can be used for vibration applications to absorb the energy at high frequencies.
•NOx conversion efficiency was influenced by metal substituted zeolite.•In the low temperature window, Cu-Z has a greater tendency than Fe-Z to recover active sites.•SAR value of zeolite will ...determine the efficiency of selective catalytic reduction.
Internal combustion (IC) engines rely heavily on NOx emissions. Various studies are being conducted to lower NOx emission in order to achieve the BS-VI norms. This review examines a zeolite catalyst using metal substitutes, primarily copper Cu, and iron Fe, and compares it to a commercial vanadium catalyst in terms of deNOx efficiency and deactivation process. Based on the size of pores of zeolite, it has been classified into large size, medium size and small size zeolites. At low temperature, small pore zeolite with Cu substituted has better deNOx efficiency with higher thermal stability with high-temperature reaction conditions. Whereas, Cu-SSZ-13 & Cu-SAPO-34 exhibits wider temperature window and also exhibits good thermal stability even below 350 °C. Si/Al ratio (SAR) plays a vital role in deNOx efficiency.
Industrial vehicle operator's solace and safety have gained significant consideration because of the increment in occupational health issues and accidents. The purpose of this work was to amend the ...design of the excavator driver cabin through human factor analysis. Thirty operators of excavators who were serving as subjects, were interviewed and identified that their wrist, upper arm and trunk were at a higher risk level while operating. Photograph of the operators was taken and the work environment was simulated. RULA (Rapid Upper Limb Assessment) and REBA (Rapid Entire Body Assessment) scoring was made on different simulated work posture of operators using CATIA V5 and UEAT1.8 softwares. Based on overall RULA and REBA scoring, it was found nearly 46% of the operators were operating at a high hazard level and needed investigation immediately, whereas 35% of operators were at a medium risk level and only 19% of operators were operating safely. The individual RULA and REBA scoring proved prevalence of discomfort in wrist, upper arm and trunk while operating. Identifying the optimized conditions to hold the control levers will help to reduce the operator strain. From the design optimization in excavators, the optimal conditions to hold the control lever is found to be 40cm for popliteal height, 60.51 cm for distance from elbow to ground and 15.07º for reach angle from the seat reference point.
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