All countries regulate CO
2
emissions, triggering similar evolution on powertrain at a similar pace all over the planet. Engine irregularities are more severe due to downsizing and uptorquing. ...Torsional filtration targets are also challenging powertrain performance. This drives powertrain market and more efficient torque transfer system. Conventional filtration solutions such as clutch/dampers and DMF have their own limitations. For the past few years the addtion of centrifugal pendulum absorber meets the required filtration target. The vehicle architecture and type of damper accompanying pendulum absorber contribute to the dynamic stability and performance. In this study, we have shown the behaviors of DMF pendulum in rear wheel driveline with six speed manual transmission. Normally the performance of a pendulum in high engine speed range is not so efficient compare to lower speed range. This study mainly focuses on variations on design parameters of pendulum, which enables better filtration in high speed range.
Design and Analysis of an Automotive Vacuum Pump Thaslim, A. Anisa; Suresh Kumar, J.; Jayachandran, A. ...
Applied Mechanics and Materials,
07/2014, Letnik:
592-594, Številka:
Dynamics of Machines and Mechanisms, Industrial Research
Journal Article
Recenzirano
In the present study, mathematical modelling of different chamber profile of the vacuum pump to evaluate the evacuation time is developed. The validity of the developed mathematical modelling is ...demonstrated by performing an experiment on the vacuum pump with elliptical profile. The performance of the elliptical profile is also compared with that of the circular profile chamber of vacuum pump. It is shown that the evacuation time of vacuum pump with an elliptical chamber is lower than with a circular profile. Various parametric studies are also performed to investigate the effect of rotor eccentricity, ratio of minor and major axes of the elliptical profiles, air tank capacity on evacuation time of the vacuum pump.
Osteopetrosis is a rare genetic bone disorder arising due to a defect in the differentiation or function of osteoclast which results in a generalized increase in bone mass. Osteomyelitis is one of ...the most common complications because of decreased bone marrow function and compromised blood supply. Radiologist plays a vital role in diagnosing osteopetrosis. Here, we present two cases of autosomal dominant osteopetrosis Type II (ADO II) with secondary osteomyelitis changes which were reported to our department. One of these two cases presented with secondary osteomyelitis in both maxilla and mandible and features of rickets, which is very rarely seen in ADO II. To the best of our knowledge, the presentation of rickets with ADO is the first of its kind to be reported. In this paper, we describe the clinical and radiological features leading to the diagnosis of ADO in these two patients. Further, a review of the literature regarding ADO is discussed.
Background: Temperature measurement is an important procedure in the diagnosis and management of childhood illness. Rectal measurement of temperature is often done with resentment from the child, ...the parents as well as the physician. Intra aural (Tympanic), temporal artery and axillary measurements are commonly undertaken for temperature recording in children. The aim of the study was to compare the various methods of temperature measurement (intra aural, temporal artery and axillary measurements) in children. This was a hospital based descriptive study (pilot study) from a pediatric tertiary care center.Methods: This was a hospital based descriptive study (pilot study) from a pediatric tertiary care center. 250 children admitted with history of fever in the pediatric ward. All consecutive children with fever were recruited for the study. Children with ear pain, ear discharge and wax in the ear were excluded.Results: Inter-group comparison was performed using student paired t-test. There was no difference in the temperature measured by axillary and temporal artery touch when compared with intra aural. Temperature measured by infra-red temporal at 3 cm showed significant lower temperature. Temporal artery and axillary measurements had a correlation coefficient of 0.74 and 0.64 respectively when compared with intra aural measurement.Conclusions: Temporal artery and axillary measurements are not significantly different from intra aural measurement in children. For the ease of measurement, better correlation, better compliance of the child, temporal artery method can be a reliable preferred temperature measurement in children with fever.
Osteopetrosis is a rare genetic bone disorder arising due to a defect in the differentiation or function of osteoclast which results in a generalized increase in bone mass. Osteomyelitis is one of ...the most common complications because of decreased bone marrow function and compromised blood supply. Radiologist plays a vital role in diagnosing osteopetrosis. Here, we present two cases of autosomal dominant osteopetrosis Type II (ADO II) with secondary osteomyelitis changes which were reported to our department. One of these two cases presented with secondary osteomyelitis in both maxilla and mandible and features of rickets, which is very rarely seen in ADO II. To the best of our knowledge, the presentation of rickets with ADO is the first of its kind to be reported. In this paper, we describe the clinical and radiological features leading to the diagnosis of ADO in these two patients. Further, a review of the literature regarding ADO is discussed.
Extensive measurements of cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations in the South Asian outflow to the northern Indian Ocean were carried out on board an instrumented ...research vessel, as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) during the winter season (January–February 2018). Measurements include a north–south transect across the South Asian plume over the northern Indian Ocean and an east–west transect over the equatorial Indian Ocean (∼2∘ S), which is far away from the continental sources. South Asian outflow over the northern Indian Ocean is characterized by the high values of CCN number concentration (∼5000 cm−3), low CCN activation efficiency (∼25 %) and a steep increase in CCN concentration with the increase in supersaturation. In contrast, low CCN concentration (∼1000 cm−3) with flat supersaturation spectra was found over the equatorial Indian Ocean. The CCN properties exhibited significant dependence on the geometric mean diameter (GMD) of the aerosol number size distribution, and CCN activation efficiency decreased to low values (<20 %) at the time of new-particle formation events over near-coastal and remote oceanic regions. The analysis of the activation efficiencies for the “similar” aerosol size distributions over the northern Indian Ocean indicated the primary role of aerosol number size distribution on CCN activation efficiency. The dependence of CCN properties and activation efficiency on size-segregated aerosol number concentration, especially during the ultrafine (<100 nm) particle events, is investigated in detail for the first time over the region.
The particle number concentrations, size distributions, and new particle formation (NPF) events were investigated in the South Asian outflow over the southeastern Arabian Sea (SEAS), the northern ...(NIO) and equatorial Indian Ocean (EIO) during the winter of 2018 based on the extensive measurements of particle number size distributions in size range 10–414 nm in the marine atmospheric boundary layer (MABL) as part of the Integrated Campaign for Aerosols, gases, and Radiation Budget (ICARB - 2018) experiment. The total particle concentrations were higher (as high as 106 cm−3; mean ~8857 ± 13425 cm−3) over the SEAS in the proximity to the continental outflow, which gradually decreased to reach the lowest values over the remote EIO (~3206 ± 4406 cm−3). Several NPF events with conspicuous bimodal size distributions and 3–10 times enhancement in nucleation particle (<25 nm) concentrations were noticed. NPF occurred more frequently over the remote oceanic EIO, but more intensely over the regions in the continental proximity demonstrating the varying precursor vapor source strengths. The vertical winds and dew point temperatures revealed the entrainment of free tropospheric air masses to the MABL enabling the downward transport of the nucleation mode particles, possibly formed in the free tropospheric altitudes, to the MABL which advected southward along with the primary outflow aerosols due to north-easterly surface winds. Collocated submicron aerosol chemical composition measurements revealed that most of the events were associated with enhanced particulate organics mass concentrations. Further investigations suggested that volatile organic compounds were possibly involved in the NPF pathways whose sources were advected polluted plumes in the outflow regions and marine emissions over the remote ocean. The newly formed particles grew to larger sizes with a median growth rate of 12 nm h−1, which suggest that these NPF events can contribute considerably to the regional aerosol loading, and potentially affect regional climate.
•Multimode PNSDs over the northern Indian Ocean.•New particle formation (NPF) events in coastal and remote ocean.•NPF events associated with subsidence of free-tropospheric air masses to the MABL.•Enhanced organics mass concentrations during the NPF events.
Regional climatic implications of aerosol black carbon (BC), which has a wide variety of anthropogenic sources in large abundance, are well recognized over South Asia. Significant uncertainties ...remain in its quantification due to a lack of sufficient information on the microphysical properties (its concentration, size, and mixing state with other aerosol components) that determine the absorption potential of BC. In particular, the information on the mixing state of BC is extremely sparse over this region. In this study, the first observations of the size distribution and mixing state of individual refractory black carbon (rBC) particles in the South Asian outflow to the south-eastern Arabian Sea and the northern and equatorial Indian Ocean regions are presented based on measurements using a single particle soot photometer (SP2) aboard the Integrated Campaign for Aerosols, gases, and Radiation Budget (ICARB-2018) ship during winter 2018 (16 January to 13 February). The results revealed significant spatial heterogeneity of BC characteristics. The highest rBC mass concentrations (∼938±293 ng m−3) with the highest relative coating thickness (RCT; the ratio of BC core to its coating diameters) of ∼2.16±0.19 are found over the south-east Arabian Sea (SEAS) region, which is in the proximity of the continental outflow. As we move to farther oceanic regions, though the mass concentrations decreased by nearly half (∼546±80 ng m−3), BC still remained thickly coated (RCT∼2.05±0.07). The air over the remote equatorial Indian Ocean, which received considerable marine air masses compared to the other regions, showed the lowest rBC mass concentrations (∼206±114 ng m−3) with a moderately thick coating (RCT∼1.73±0.16). Even over oceanic regions far from the landmass, regions that received the outflow from the more industrialized east coast/the Bay of Bengal had a thicker coating (∼104 nm) compared to regions that received outflow from the west coast and/or peninsular India (∼86 nm). Although different regions of the ocean depicted contrasting concentrations and mixing state parameters due to the varied extent and nature of the continental outflow as well as the atmospheric lifetime of air masses, the modal parameters of rBC mass–size distributions (mean mass median diameters ∼ 0.19–0.20 µm) were similar over all regions. The mean fraction of BC-containing particles (FBC) varied in the range of 0.08–0.12 (suggesting significant amounts of non-BC particles), whereas the bulk mixing ratio of coating mass to rBC mass was highest (8.31±2.40) over the outflow regions compared to the remote ocean (4.24±1.45), highlighting the role of outflow in providing condensable material for coatings on rBC. These parameters, along with the information on the size-resolved mixing state of BC cores, throw light on the role of sources and secondary processing of their complex mixtures for coatings on BC under highly polluted conditions. Examination of the non-refractory sub-micrometre aerosol chemical composition obtained using the aerosol chemical speciation monitor (ACSM) suggested that the overall aerosol system was sulfate-dominated over the far-oceanic regions. In contrast, organics were equally prominent adjacent to the coastal landmass. An association between the BC mixing state and aerosol chemical composition suggested that sulfate was the probable dominant coating material on rBC cores.
Continuous measurements of the mass concentrations of composite (MT) and Black Carbon (MB) aerosols were carried out on-board an Oceanographic Research Vessel (ORV) Sagar Kanya (cruise number – ...SK345) during its cruise (from 16 January to 13 February, 2018) over the southeastern Arabian Sea and equatorial Indian Ocean as a part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018). In general, mass concentrations of aerosols during the cruise period of northern hemispheric winter were found to be high over the southeastern Arabian Sea (MT > 50 μg m−3; MB > 3 μg m−3), which gradually reduced to low values over the far oceanic regions of equatorial Indian Ocean (MT < 20 μg m−3; MB < 1 μg m−3). Aerosol mass size distributions were bimodal in nature having a prominent accumulation mode over both near coastal and far oceanic regions. Interestingly, BC mass fraction (FBC) also showed significant higher values (3.7%) at the far oceanic equatorial Indian Ocean, indicating the continental anthropogenic influence even in the remote environment. Over the near coastal locations of Arabian Sea, FBC increased significantly during the return phase of the cruise after a rainfall event. Considering latitudinal gradient between 15°N and 2°S, within the longitude sector of 65°E to 75°E, both MT and MB showed a scaling distance of 17.08° and 14.28° respectively. Investigation of the long-term temporal change of MT and MB over the experimental domain indicates that the values observed in the present study are significantly higher than those reported elsewhere two decades back, which is very significant over the Arabian Sea.
•Spatial variations of aerosol physical properties over Arabian Sea and Indian ocean.•Higher aerosol concentrations over Arabian sea, comparable to continental aerosols.•Significantly high values of BC over pristine equatorial Indian ocean.•Transport of anthropogenic aerosols to far Indian ocean during dry winter.•Enhancement in aerosol concentration over Indian ocean compared to INDOEX.
As a part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018), shipborne measurements of aerosol properties were carried out to study the influence of South Asian outflow ...on cloud condensation nuclei (CCN) characteristics over the South East Arabian Sea (SEAS) and equatorial Indian Ocean (EIO) during winter, 2018. The poor association between CCN concentration and mass concentrations of the major aerosol species (organic matter, sulfate, and elemental carbon) is observed over SEAS, where airmass is mostly continental. In comparison, the CCN is well-correlated with aerosol mass concentrations over remote EIO. The dependence of CCN activation (at lower supersaturations) on the ultrafine particle fraction differs between SEAS and EIO depending on the mass concentration of organic aerosols. The coexistence of small and hydrophobic aerosols (organics) decreased the CCN activation ratio during ultrafine particle events. The hygroscopicity estimated using the chemical composition of aerosols is comparable to that estimated from CCN measurements over the Indian Ocean, except for the SEAS, where organic aerosols dominate. The effect of outflow aerosols on cloud droplet number concentration (CDNC) is simulated using a parcel model, which showed a good association (R ∼0.96) with CCN measurements over the EIO; however, the estimated CDNC did not follow the CCN variation over the SEAS region. This study highlights the importance of aerosol chemical composition, especially organics, in CCN activation and cloud droplet formation in the South Asian outflow over the Indian Ocean.
•Hygroscopicity (κ) of continental aerosols over the Indian Ocean is examined.•Ultrafine particles and organics decrease the CCN activation of South Asian outflow.•CCN at 0.2% SS estimated from measured κ has positive bias over the Arabian Sea.•Estimated CDNC over near-coastal regions is mostly invariant with CCN concentration.
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