Measurement of Ambient Ammonia over the National Capital Region of Delhi,India

Mixing ratio of ambient ammonia (NH₃) was measured at various locations of the National Capital Region (NCR) of Delhi, India using a NH₃-analyzer during January 2010 to June 2012 in campaign mode. The present study has been carried out on campaign based measurement of mixing ratios of NH₃ and NO _x for short period of time over the NCR of Delhi represent the indicative values over the region. The average mixing ratio of ambient NH₃ was 20.9 ± 1.6 ppb during the period. The maximum average mixing ratio of ambient NH₃ (28.8 ± 3.0 ppb) was recorded in an industrial area surrounded by intensive vehicular traffic followed by an agricultural farm (27.5 ± 2.1 ppb), whereas the minimum (6.4 ± 1.2 ppb) was recorded in the semi-urban area. The diurnal trend of NH₃ depended on the ambient temperature at most of the sites and was affected by wind direction. Ambient NH₃ was correlated with the NO _x mixing ratio suggesting that the vehicular emission may be one of the sources of ambient NH₃ in the NCR of Delhi. However, long-term measurements of ambient NH₃ and their precursors will lead to seasonal variation of source apportionment over the NCR, Delhi, India.     

Measurement of Ambient NH<Subscript>3</Subscript>, NO and NO<Subscript>2</Subscript> at an Urban Area of Kolkata,India

Mixing ratios of ambient NH₃, NO and NO₂ were measured in campaign mode at Kolkata a megacity of Indo-Gangetic plain of India to study the diurnal variation and mixing ratios of NH₃, NO and NO₂ during 24–27 February 2012. The present study has been carried out on campaign based measurement of mixing ratios of NH₃, NO and NO₂ for short period of time at Kolkata represent the indicative values over the region. The average mixing ratios of ambient NH₃, NO and NO₂ were recorded as 43.4 ± 7.0 ppb, 46.0 ± 8.7 ppb and 31.9 ± 5.5 ppb at Kolkata. In the present case, significant diurnal variation of NH₃, NO and NO₂ were recorded at Kolkata during study. Mixing ratio of ambient NH₃ reaches its maxima (78.9 ppb) at night and minimum during daytime. Result reveals that the ambient NH₃ mixing ratio is positively correlated with ambient NO (r ² = 0.395) and NO₂ (r ² = 0.404) mixing ratio and significant negatively correlated with ambient temperature (r ² = –0.669). Surface wind direction and wind speed analysis indicates that the local acitivities (livestock, drainage, agriculture, vehicles etc.,) may be the possible sources of ambient NH₃ at the observational site of Kolkata.     

Investigation of 1 GPa Controlled Clearance Piston Gauge Using Finite Element Analysis

A one GPa controlled clearance piston gauge used as a high pressure standard at KRISS was investigated. In establishing the high pressure standard, the distortion coefficient is one of the most important parameters, but it is not easy to determine. The conventional analysis using a Heydemann–Welch model has a problem when determining a stall pressure, because of the nonlinear characteristic of fall rates with respect to pressure. Some metrological characteristics, such as the distortion coefficient of the piston–cylinder assembly in free deformation (FD) mode and the jacket distortion coefficient and stall pressure in controlled clearance (CC) mode, were investigated using a finite element analysis (FEA). In particular, it was determined that the relation of cubic fall rate to jacket pressure becomes nonlinear above 600 MPa. The FEA results were verified by comparison with a 500 MPa pressure standard and a fall rate measurement of 1 GPa. The most important parameter, the distortion coefficient in the FD and CC mode, was determined to be (7.59 ± 0.24) × 10−7 MPa−1 and (3.35 ± 0.39) × 10−7 MPa−1, respectively. A zero-distortion coefficient was obtained in the FEA when around 17% of the applied pressure was used as the jacket pressure. This value was similar to the experimentally determined result of around 20%.     

Measurements of Particulate (PM2.5), BC and Trace Gases Over the Northwestern Himalayan Region of India

Ambient trace gases (NH₃, NO, NO₂ and SO₂) and black carbon (BC) were measured along with particulate matter (PM_2.5) over the northwestern Himalayan region (Palampur, Kullu, Shimla, Solan and Nahan) of Himachal Pradesh (HP), India in a campaign mode during 12–22 March 2013 to evaluate the ambient air quality of the region. The average mixing ratio of ambient NH₃, NO, NO₂ and SO₂ were recorded as 7.1 ± 2.6, 3.1 ± 1.3, 3.9 ± 1.4 and 1.7 ± 0.7 ppb respectively over the northwestern Himalayan region. The average concentration of BC was estimated as 2.2 ± 0.5 µg m^?3 over the region whereas average concentration of PM_2.5 mass was estimated as 41.8 ± 7.9 µg m^?3. The spatial variation of ambient trace gases (NH₃, NO, NO₂ and SO₂), BC and PM_2.5 over the northwestern Himalayan region, India reveals that the region is mainly influenced by local activities, i.e., tourism activities, agricultural activities, biomass burning and vehicular emission. A significant positive linear correlation of NH₃ and NH₄ ⁺ with SO₄ ^2?, NO₃ ^? and Cl^? (NH₄ ⁺ vs. SO₄ ^2? , r ² = 0.652; NH₄ ⁺ vs. NO₃ ^?, r ² = 0.701; and NH₄ ⁺ vs. Cl^?, r ² = 0.627) of the PM_2.5 indicates the possible formation of (NH₄)₂SO₄, NH₄NO₃ and NH₄Cl aerosols over the region.     

Studies on Low Altitude Clouds Over New Delhi,India Using Lidar

This study reports the altitude distribution of physical and optical properties of clouds in the lower troposphere over the urban tropical region Delhi using an UV (355 nm) lidar which is capable of operating in both day and night time. Most of the low altitude clouds are observed above the planetary boundary layer during the observation period. The low altitude cloud bottom and top height varies between 0.58 ± 0.21 and 1.5 ± 0.61 km respectively during the observation period. The depolarization ratio of the observed clouds varies from 0.18 ± 0.01 to 1.2 ± 0.58. The role of the atmospheric region below the cloud in the growth process of the cloud cell is studied. Cloud turbulence is derived to show its role in maintaining the strength of the cloud.     

Atmospheric Fine and Coarse Mode Aerosols at Different Environments of India and the Bay of Bengal During Winter-2014: Implications of a Coordinated Campaign

In this paper, we present mass concentrations of particulate matter [PM_2.5, PM₁₀ size fractions and total suspended particulates (TSP)] measured simultaneously over land stations (Kullu, Patiala, Delhi, Ajmer, Agra, Lucknow, Varanasi, Giridih, Kolkata, Darjeeling, Jorhat, Itanagar, Imphal, Bhubaneswar, and Kadapa), mostly distributed across the Indo-Gangetic plain (IGP) of India as well as in the marine atmosphere over Bay of Bengal (BoB) in the period from 20 January to 3 February, 2014. The main objective of this study was to quantify the continental outflow of particulates (PM_2.5, PM₁₀ and TSP) from IGP and associated regions into the BoB along with low level north-east wind flow during winter monsoon period. The present study provides a glimpse of the aerosol loading over the IGP region. During this campaign, the highest average PM_2.5 (187.8 ± 36.5 µg m^?3, range 125.6–256.2 µg m^?3), PM₁₀ (272.6 ± 102.9 µg m^?3, range 147.6–520.1 µg m^?3) and TSP (325.0 ± 71.5 µg m^?3, range 220.4–536.6 µg m^?3) mass concentrations were recorded at Varanasi, Kolkata and Lucknow over middle and lower IGP regions. The PM_2.5 (average 41.3 ± 11.9 µg m^?3; range 15.0–54.4 µg m^?3), PM₁₀ (average 53.9 ± 18.9 µg m^?3; range 30.1–82.1 µg m^?3) and TSP (average 78.8 ± 29.7 µg m^?3; range 49.1–184.5 µg m^?3) loading over BoB were found to be comparable to land stations and suggests possible continental outflow. Over the continental region, the highest PM_2.5/PM₁₀ ratio was recorded at Delhi (0.87). The PM_2.5/PM₁₀ ratio over BoB (0.77) was found to be quite high and comparable to Varanasi (0.80) and Agra (0.79).     

Preparation of PLGA/β-TCP composite scaffolds with supercritical CO 2 foaming technique

A high porosity scaffold with suitable compressive strength prepared by a gentle method has become a pressing need. To meet this demand, poly(DL-lactide-co-glycolide) (PLGA) and β-tricalcium phosphate (β-TCP) were designed to prepare composite scaffolds by the supercritical technique. The preparation process consisted of three units: the mixing of PLGA and β-TCP, compression molding of the mixture, and the foaming process. Six influencing factors — temperature, pressure of the scCO₂ system, maintaining time of scCO₂, the ratio of β-TCP to PLGA, the rate of depressurization, and the molecular weight — were investigated. The results collectively indicated that the optimized conditions for the foaming process were that CO₂ pressure and temperature be 8MPa and 39°C, respectively, which should be kept for 8h; the content of β-TCP in the mixture should be 25% and the depressurizing rate be 0.1 MPa/s, using PLGA of an 80kDa molecular weight. Scaffolds with a porosity of 65.47% and a compressive strength of 4.76 MPa could be obtained. The pore size ranged around 100 µm. The material’s use as tissue engineering scaffolding is expected.     

Gravity Induced Absorption Changes in <Emphasis Type="Italic">Phycomyces blakesleanus</Emphasis> and Coleoptiles of <Emphasis Type="Italic">Zea mays</Emphasis> as Measured on the Drop Tower in Bremen (FRG)

Various spectroscopic experiments performed on the AIRBUS ZERO G in the years 2002 to 2007 clearly exhibited optical reflection changes as a result of gravitational changes (GIAC = Gravity Induced Absorption Change) in Phycomyces sporangiophores and corn coleoptiles. GIACs that occurred during flight parabolas in response to hyper- and microgravity were detected by a micro dual wavelength spectrometer (MDWS) for wavelengths pairs in the visible and the near infrared. We assume that GIACs indicate redox-changes of electron transport components such as flavins and cytochromes. Because microgravity on the AIRBUS 300 ZERO G only amounts to moderate values of ±4 ×10^− 2 g, i.e. far below sensitivity of the MDWS, we performed an experiment on the drop tower in Bremen (Germany) that generates microgravity as low as 4 ×10^− 5 g for 4.7 s. We detected small but significant GIACs during the microgravity phase, different in various specimen.     

Source characterization of total suspended particulate matter near a riverbed in Central Taiwan

Samples of total suspended particulate (TSP) matter were collected by using TSP samplers from certain areas representing the estuary of the Jhuoshuei River, Taiwan during monsoon and non-monsoon seasons in 2005. A total of 12 elements and nine inorganic ions were identified by inductively coupled plasma atomic emission spectrometry (ICP-AES) and ion chromatography (IC), respectively. Enrichment factors explaining a preponderance of the variance in the data were applied to the data sets. The results show that wind direction significantly affected the concentration of TSP during the monsoon season; moreover, these concentrations were also markedly higher during the monsoon than during the non-monsoon season. Low enrichment factor (EF) values (1.18-2.88) were observed during the monsoon for Ca, Fe, Na, Ba, Cd, Co, Li, Mn, and Sr, reflecting the importance of dust contribution by natural processes. Conversely, the EF values calculated for Ca, K, Ba, Co, Li, and Zn were relatively high (7.03-20.26) when observed during non-monsoon season, a phenomenon suggesting that they are mainly contributed from non-crustal sources. The observations of relatively enhanced EF values during monsoon indicate that the changes in wind direction between monsoon and non-monsoon seasons are associated with the different contribution sources. The high concentration of TSPs observed in the ambient air is believed to be primarily due to surface soil particle emission from the riverbeds.     

Study on Comparison of Indian Ozonesonde Data with Satellite Data

This paper assesses the quality of ozone data of modified Brewer Mast (MBM) balloonborne ozonesonde and its comparison with MOZAIC Data (version 4), TES data (version 6), UARS MLS (version 5), EOS Aura MLS Data (version 5) and SBUV (version 8.1). The stations that have been used for this analysis: Delhi (28.58N, 77.20E) (Ozonesonde, MOZAIC, TES, UARS MLS, AURA MLS and SBUV), Pune (18.53N, 73.85E) Ozonesonde, UARS MLS, AURA MLS, SBUV and MOZAIC over Bombay presently called Mumbai (20.19N, 72.34E)), Madras presently called Chennai (13N, 80.18E) (MOZAIC and MLS) and Trivandrum (8.48N, 76.95E) (Ozonesonde, UARS MLS, AURA MLS and SBUV). Analysis shows that reasonable amounts of ozonesonde data are of good quality according to WMO criteria (1982) as 70–80 % of data over all the three stations are within the normalization factor of 1.3–0.8 ± (0.05–0.1) although some major changes in instrumentation e.g., new fast running nonreactive Teflon pump, modernized electronics, and smaller case since 1971. Several international intercomparisons carried out in 1970, 1982, 1991 and 1996 respectively, has also been confirmed the same, in spite of fundamental differences among the methods of these intercomparisons as well as ozonesonde types on procedure for sonde preparation, data processing and analysis. The intercomparison of Indian ozonesonde data (1995–1999) is made at troposphere with MOZAIC data (1995–2000) over Delhi and Pune/Mumbai, ozonesonde data (2013–2014) also compare with TES (2013–2014) special observation data over particular station Delhi at troposphere and at stratosphere with UARS MLS (1995–1999), EOS Aura MLS (2005–2014) and SBUV (2005–2013) data at Delhi, Pune and Trivandrum. Tropospheric value of Ozonesonde shows on average 10–20 % higher value than MOZAIC value over Delhi and Pune except in the lower height (<800 hPa) but ozonesonde show 10–15 % higher value than TES over Delhi in the lower height (<800 hPa). The percentage difference between ozonesonde data and UARS MLS data at Delhi, Pune and Trivandrum show variation of ±15 % and ozonesonde data, EOS Aura MLS and SBUV data at Delhi, Pune and Trivandrum show variation of ±45 % in the vertical range of 46 to 10 hPa, where, MLS data show highest accuracy.     

Hydrogen production in a reversible flow filtration combustion reactor

The noncatalytic process of syngas production by means of partial oxidation of methane by air oxygen in a reversible flow filtration combustion reactor has been investigated experimentally. We have investigated the influence of the equivalent ratio and the specific mass flow of the fuel mixture on the composition of conversion products and the maximum temperature in the reaction zone. The optimal conditions for the process providing the most effective conversion of methane to syngas have been established. The concentration of hydrogen is maximal for the equivalent ratio γ = 2.8 and the specific flow rate g = 1.8 kg / (m²⋅s).     

Melt-electrospinning of polypropylene with conductive additives

In this paper, the feasibility of fabricating polypropylene (PP) nanofibres was investigated using conductive additives such as sodium oleate (SO) and sodium chloride (NaCl) during melt-electrospinning. PP of high melt flow index (MFI = 2000) was used with varying amounts of additives. The effects of amount of additives on the fibre diameter and morphology were investigated. The lowest fibre diameters of 0.371 ± 0.106 and 0.310 ± 0.102 μm were achieved with 7 % SO and 5 % NaCl, respectively. The fabrication of nanofibres was attributed to the increase in the electrical conductivity with the introduction of the additives. The increase in the electrical conductivity was greater in the case of NaCl, due to the smaller ionic size of NaCl. Differential scanning calorimetry results showed complex melting behaviour during the heating cycles for the fibres containing SO; and double melting peaks during the second heating cycle for the fibres containing NaCl. X-ray diffraction studies showed the fibres fabricated with the additives contained lower degrees of crystallinity compared to the as-spun fibre and the crystallinity was increased after annealing. The fibres fabricated with the additives contained α-form crystals only which did not change after annealing. The fibres fabricated from pure polymer and with the additives were hydrophobic in nature. The hydrophobicity was marginally decreased with the addition of SO and NaCl.     

Uncertainty Assessment in Cognitive Load for Multiple Object Tracking Based on EEG

Cognitive load varies the attention level, which has serious consequences in complex dynamic situations. Assessment of uncertainty in cognitive load during multiple object tracking task is necessary, as it is used to improve the cognitive capabilities. The present research work investigates the uncertainty in cognitive load of multiple object tracking task using electroencephalograph (EEG) on 25 football players. A d2 test of neuropsychological measure of attention was employed before starting the experiment. Each player participated in four levels of the task with variation in the cognitive load, which varies in terms of the targets from 2 to 5. Percentage changes in the power spectral density were estimated for the cognitive levels. Results show that the percentage changes were much more in high cognitive load than in low cognitive load. Significant changes (p < 0.05) were observed in level 1 (− 11.07 to 1.91%), level 2 (− 3.13 to − 14.51%), level 3 (− 6.33 to − 19.46%) and level 4 (− 8.10 to − 20.88%). Variation in the EEG data in terms of the combined uncertainty corresponds very well with low to high cognitive loads. The fourth level of the task with high cognitive load has more uncertainty than the low cognitive load levels. The results are useful for assessing the cognitive state of the player, which is valuable for the design of the effective training model.     

Combustion synthesis and structural characterization of Li–Ti mixed nanoferrites

Polycrystalline samples of the mixed nanoferrites, Li_{0·5 + 0·5x} Ti _x Fe_{2·5 − 1·5x} O₄ (0·02 ≤ x ≤ 0·1), were prepared by combustion method at lower temperatures compared to the conventional high temperature sintering for the first time at low temperatures, using PEG which acts as a new fuel and oxidant. XRD patterns reveal a single-phase cubic spinel structure. The as synthesized Li–Ti ferrites are in nanocrystalline phase. The crystallite size was found to be in the range 16–27 nm. SEM images reveal rod-like morphology in all the samples with a discontinuous grain growth. The B–H loops have been traced using VSM technique, for all the compositions, at room temperature and the hysteresis parameters are calculated. Saturation magnetization decreases with increase in Ti content due to the fact that the Ti^4 + ion, which is a non-magnetic ion, replaces a magnetic Fe^3 + ion. The hysteresis loops show clear saturation at an applied field of ±10 kOe and the loops are highly symmetric in nature. The cation distribution is known indirectly by using saturation magnetization values.     

Turbidity Sensor for Bacterial Growth Measurements in Spaceflight and Simulated Micro-gravity

For the BIOFILTER flight experiment a set of turbidity sensors was developed for the measurement of the growth rate of the bacteria Xanthobacter autrophicus GJ10 in a fluid medium. During the flight experiment on FOTON M2 in 2005, bacterial growth was measured revealing growth rates between 0.046–0.077 h^− 1 in microgravity, i.e. approximately 1.5–2.5 times slower than routinely measured under optimal laboratory conditions on earth. To increase confidence in the equipment and for comparison of the results, a ground-reference experiment was carried out in 2006, using BIOFILTER hardware mounted on a random positioning machine (RPM). The RPM performed random rotations at 0.5°/min (for settling compensation) and 90°/min (for simulated microgravity) while the environment was controlled, accurately repeating the BIOFILTER flight temperature conditions. Despite the rotations of the RPM, a normal growth rate of 0.115 h^− 1 was confirmed in both cases. The operation of the turbidity sensor was verified. Biological interpretation of the measurements is however compromised due to poor mixing and other unknown physical and biological phenomena that need to be addressed for further space experiments using these kinds of systems.     

Fatigue properties of notched specimens made of FeP04 steel

Fatigue properties of specimens with different notches made of FeP04 steel are presented. The specimens are characterized by double symmetric lateral notches with radius of the notch root ranging from ρ = 0.2 to 10 mm. An MTS 809 servohydraulic device was used for the tests. All fatigue tests were performed under force control by imposing a constant value of the nominal load ratio (R = 0) and a load amplitude P _a  = 6 kN for the notch root ρ = 0.2 mm and 7 kN for the notch roots ρ = 1.25, 2.5 and 10 mm. The test frequency varied from 13 to 15 Hz. During the tests performed under constant loading, we observe the fatigue weakening of the material and an increase in strain.     

Synthesis and photoluminescence characterization of Ce<Superscript>3 + </Superscript> and Dy<Superscript>3 + </Superscript> activated ALa(WO<Subscript>4</Subscript>)<Subscript>2</Subscript>(A = Na and Li) novel phosphors

In this paper, we report the synthesis of Ce^3 + and Dy^3 + activated alkali lanthanide tungstates, ALa(WO₄)₂(where A = Na and Li), prepared by solid state reaction method. The prepared phosphors were characterized by X-ray diffraction and photoluminescence techniques. The NaLa(WO₄)₂:Dy^3 + and LiLa(WO₄)₂:Dy^3 + phosphors show two emission peaks at around 574 and 486 nm (λ_exc = 354 nm). NaLa(WO₄)₂:Ce^3 + and LiLa(WO₄)₂:Ce^3 + show two emission peaks at around 378 and 425 nm (λ_exc = 350 nm). Excitation wavelengths of Ce^3 + and Dy^3 + activated alkali lanthanide tungstates are in near UV region i.e. Hg free excitation. These characterizations of phosphors are applicable for solid state lighting. Accordingly, Ce^3 + and Dy^3 + activated NaLa(WO₄)₂ and LiLa(WO₄)₂ may be the promising materials for solid state lighting applications.     

Effect of Firing Temperature on the Structure and Superconducting Properties of YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7−<Emphasis Type="Italic">x</Emphasis></Subscript> Films

YBa₂Cu₃O_7−x (YBCO) films were prepared on LaAlO₃ single crystal substrate under various firing temperatures (750–800 °C) in the crystallization process by metalorganic deposition (MOD) method. The coating solution was made by mixing the fluorine-free precursor solution containing Y and Cu with Ba–fluorine precursor solution (Ba-TFA). The effect of firing temperature on the structure and superconducting properties of YBCO films was systematically investigated. The results indicated that YBCO-films were smooth, crack-free, exhibited good textures and retain high oxygen content according to the XRD and SEM images. Sample of YBCO-film fired at 780 °C showed highest superconducting properties including high critical transition temperature T _c=89 K, sharp transition temperature ΔT _c<1 K, and critical current density J _c=2.8 MA cm⁻², which are attributable to excellent in-plane textures and dense microstructures with good connectivity between the grains.     

Nanostructural modification of an Al–C–Ti coating on alloy AZ91D under the multipulse action of Nd:YAG and Ng-glass lasers

Experimental results on the nanostructural modification of an Al–C–Ti coating on magnesium alloy AZ91D under the multipulse action of Nd:YAG lasers (λ = 1064 nm, τ = 20 ns, and E = 200 mJ) and Nd-glass lasers (λ = 1060 nm, τ = 85 ns, and E = 2 J) are given. It is shown that the formation of the found nanocrystalline coating structure with a grain size of 35 to 400 nm involves the process of background deposition of ablated particles and condensed clusters formed in the plasma plume.     

Cost-effective electrostatic-sprayed SrAl<Subscript>2</Subscript>O<Subscript>4</Subscript>:Eu<Superscript>2 + </Superscript> phosphor coatings by using salted sol–gel derived solution

3 Mol% of europium doped strontium aluminate (SrAl₂O₄:Eu^2 +) coatings on silicon substrates were prepared by electrostatic spray deposition method using a salted sol–gel derived solution as a starting material. As-deposited films at 100°C for 5 h were heated at 1100°C for 2 h under a reducing ambient atmosphere of 95%N₂ + 5%H₂. Nanocrystalline SrAl₂O₄ film was confirmed by surface morphological and crystallographic analyses. Monitored at 520 nm, the excitation spectrum showed a broad band from 300 ~ 500 nm and the emission intensity showed a maximum yellow peak intensity at 512 nm with a broad band from 460 ~ 610 nm.