742 research outputs found

    Chloride and sodium ion increases in rain from salt seeded clouds

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    Chloride and sodium ion concentrations in rainwater from warm clouds seeded with a salt soapstone mixture were two to three times greater than in rain from non-seeded clouds east of Poona, India, during the 1974 summer monsoon. The warm cloud seeding experiment, begun in 1973 and studied intensively in 1974, 1976, 1979 and 1980, involved two 1600 sq. km experimental areas, each having 40 raingauges and separated by an intervening buffer (Fig. 1). Crossover randomization was use

    Chemical composition and size distribution of atmospheric aerosols over the Deccan Plateau, India.

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    Measurements on atmospheric total aerosol were made at Poona during the summer and winter seasons of 1978–79. An Andersen particle sampler Model 20–810, Mark II (Andersen 2000 Inc. U.S.A.) which samples atmospheric particles with diameters ranging between 0.4 and 10.0 μm was used for the measurement. The mass distribution of the total aerosol, and separately for the chloride, sodium, ammonium, sulphate and nitrate components were obtained. The mass distribution of the aerosols exhibited a bimodal distribution in the size ranges 0.4–0.6 μm and 5–6 μm. The chloride and sodium components exhibited by and large a unimodal distribution. The ammonium and sulphate components exhibited a bimodal distribution during the monsoon and a unimodal distribution during the winter. The nitrate component exhibited a bimodal distribution during the monsoon and winter. The molecular form of this component appears to be ammonium nitrate in the sub-micron range and sodium nitrate in the higher size range (1–10 μm)

    Variation in the ionic composition in convective showers in Pune, India

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    Rain water samples of equal volume (100 ml) were collected sequentially from 5 convective shower events for a period of 2 years during the summer monsoon seasons of 1988 and 1989 at Pune. A marked decrease in the concentrations of soil-oriented elements Na+, K+, Ca2+ and Mg2+ was observed in the first few samples in all the events followed by a decrease in pH of the subsequent samples. Surprisingly, SO42- also showed similar variation, indicating that soil is contributing some SO42- in rain water. Washout process appears to be an important mechanism for the removal of the major ions from the atmosphere. However, rainout processes seem to be important for the removal of NO3- ions. The study points out that sequential sampling during a single shower appears to give better information about the relationship among H+, Na+, K+, Ca2+, Mg2+, SO42- and NO3- as compared to bulk sampling for longer duration

    Characteristics of aerosols at traffic junctions in Pune city

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    Vehicular emissions are one of the potential sources of air pollution in the urban regions. Pune, one of the rapidly growing cities of India, faces the severe threat from this problem. Observations of total suspended particulates and Aitken nuclei were conducted at 4 traffic junctions in Pune city during summer (May 2000) and winter (Jan-Feb. 2001). Concentrations of TSP crossed the CPCB limit, recommended for commercial zone, at all the traffic junctions and also the number density of Aitken nuclei was very high. However, aerosols were alkaline in nature, in spite of high concentrations of SO4 and NO3, mainly due to the neutralizing effect of Ca, NH4, Na, Mg and K

    Studies of trace gases and Aitken Nuclei at inland and coastal stations - A part of INDOEX programme

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    As a part of the Indian Ocean Experiment (INDOEX) programme, ground-based measurements of trace gases (SO2, NO2, NH3 and O3) and Aitken Nuclei (AN) were carried out at Pune during March-April 1998. Also, measurements of surface ozone and AN were made during 5-10 January 1998, the inter comparison campaign of various instruments at Thiruvananthapuram. The mean concentrations of SO2, NO2, NH3 and O3 at Pune were 3.75, 5.81, 3.21 and 57.8 μg/m3 respectively and that of O3 at Thiruvananthapuram was 44 μg/m3. The average concentration of AN was about five times higher at Pune (19,000/cm3) than that at Thiruvananthapuram (4,400/cm3), indicating more pollution at Pune than at Thiruvananthapuram. The diurnal variation of surface ozone showed high concentrations during the day and low concentrations during the night at both the locations. Diurnal variation of AN at Pune showed a daytime maximum and a night-time minimum. Whereas, at Thiruvananthapuram night-time values were higher than the daytime values which can be attributed to the influence of the land and sea breeze

    Atmospheric aerosol characteristic studies at Pune and Thiruvananthapuram during INDOEX programme - 1998

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    Total suspended particulates (TSP) and mass size distribution of aerosols were monitored by using a high-volume air sampler and a low-volume 9-stage Anderson sampler, respectively during March-April 1998 at Pune and during 5-9 January 1998 at Thiruvananthapuram. All these samples were extracted for water-and acid-soluble components using the standard extraction method. The water-soluble extracts were analysed for Cl, SO4, NO3, NH4, Na, K, Ca and Mg and acid-soluble extracts for Al, Fe, Mn, Cu, Zn, Pb, Cd, Ni and Sb. The concentration of TSP varied from 67 to 185 μg/m3 with an average of 122 μg/m3 at Pune and from 35 to 73 μg/m3 with an average of 57 μg/m3 at Thiruvananthapuram. The mass size distribution of aerosols showed bimodal distribution having one peak in coarse mode and the other in fine mode at both the locations. The results of the study are presented here

    A Mechanical Mass Sensor with Yoctogram Resolution

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    Nanoelectromechanical systems (NEMS) have generated considerable interest as inertial mass sensors. NEMS resonators have been used to weigh cells, biomolecules, and gas molecules, creating many new possibilities for biological and chemical analysis [1-4]. Recently, NEMS-based mass sensors have been employed as a new tool in surface science in order to study e.g. the phase transitions or the diffusion of adsorbed atoms on nanoscale objects [5-7]. A key point in all these experiments is the ability to resolve small masses. Here we report on mass sensing experiments with a resolution of 1.7 yg (1 yg = 10^-24 g), which corresponds to the mass of one proton, or one hydrogen atom. The resonator is made of a ~150 nm long carbon nanotube resonator vibrating at nearly 2 GHz. The unprecedented level of sensitivity allows us to detect adsorption events of naphthalene molecules (C10H8) and to measure the binding energy of a Xe atom on the nanotube surface (131 meV). These ultrasensitive nanotube resonators offer new opportunities for mass spectrometry, magnetometry, and adsorption experiments.Comment: submitted version of the manuscrip

    Primary Squamous Cell Carcinoma of the Liver: An Uncommon Finding in Contrast-Enhanced Ultrasonography Imaging

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    Primary squamous cell carcinoma (SCC) of the liver is rare tumor with an unfavorable prognosis. We report a case of advanced primary SCC of the liver arising adjacent to a nonparasitic liver cyst, invading into the right diaphragm and the right lung tissue. Contrast-enhanced ultrasonography (CE-US) demonstrated unique enhancement in the late vascular phase, which was incompatible with those observed in hepatocellular carcinoma, cholangiocellular carcinoma, or metastatic adenocarcinoma. The patient underwent surgical resection of the tumor followed by systemic chemotherapy with 5-fluorouracil (5-FU) and cisplatin (CDDP), while radiation chemotherapy was not applied because of relatively poor performance status. Although postoperative image analysis revealed no recurrence 4 months later, the patient died 13 months after the operation from recurrence. Immunohistological analysis of the resected specimen revealed that this SCC contained many capillary endothelial vessels expressing CD31 or CD34, possibly reflecting the unique imaging pattern in the late vascular phase of CE-US, which has been reported in choangiolocellular carcinoma. In addition, we reviewed which kind of treatment would be suitable for advanced hepatic primary SCC in the literature. From the review, it could be proposed that a combination of radiation therapy, systemic chemotherapy (5-FU and CDDP) and surgical resection, if possible, is appropriate for advanced primary SCC of the liver

    Abrasion resistance and compressive strength of unprocessed rice husk ash concrete

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    This paper investigates the effects of adding natural rice husk ash collected from uncontrolled burning and without previous grinding (NRHA) as cement replacement in concrete. To obtain an adequate particle size, NRHA was mixed with coarse aggregate for a convenient period of time before adding the other components. Compressive strength, water absorption, porosity, and abrasion resistance expressed as weight loss were examined. Test results show that decreasing the particle size through mixing with coarse aggregate improved the compressive strength, reduced the permeability, and increased the abrasion resistance of concrete. By mixing NRHA with aggregate for 8 min, abrasion resistance improved by 10.35 and 23.62% over the control concrete at 28 and 91 days, respectively. Incorporating NRHA in concrete by grinding with coarse aggregate during the mixing process could be suitable for making normal-strength concrete and for applications where abrasion resistance is an important parameter. In addition, using NRHA as a partial replacement cement contributes to the reduction of CO2 emissions due to the production of cement

    Diffuse idiopathic skeletal hyperostosis in ancient clergymen

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    Diffuse idiopathic skeletal hyperostosis (DISH) is a common but often unrecognized systemic disorder observed mainly in the elderly. DISH is diagnosed when the anterior longitudinal ligament of the spine is ossified on at least four contiguous spinal levels or when multiple peripheral enthesopathies are present. The etiology of DISH is unknown but previous studies have shown a strong association with obesity and insulin-independent diabetes mellitus. DISH can lead to back pain, dysphagia, myelopathy, musculoskeletal impairment and grossly unstable spine fractures after minor trauma. In archeological studies a high prevalence of DISH has been demonstrated in ancient clergymen. The present study describes the pathological changes of human remains excavated from the abbey court (Pandhof) in the city of Maastricht, The Netherlands. Human remains of 51 individuals buried between 275 and 1795 ce were excavated and examined. The remains were investigated according to a standardized physical anthropological report and individuals demonstrating ossification of spinal ligaments and/or multiple peripheral enthesopathies were included in the study group. The authors reviewed all available material and after reaching consensus, each abnormality found was given a diagnosis and subsequently recorded. After examination, 28 individuals were considered to be adult males; 11 adult females; three adults of indeterminate sex and nine individuals were of sub adult age. The mean age at death for adults was 36.8 years. Seventeen adult individuals (40.4% of all adults), displayed ossifications of at least four contiguous spinal levels and/or multiple enthesopathies of the appendicular skeleton and were therefore, assigned the diagnosis DISH. The mean age of these individuals was 49.5 ± 13.0 years. In at least three of these individuals, DISH had led to extensive ossification and subsequent ankylosis of axial and peripheral skeletal structures. In this population of (presumably) clergymen and high-ranking citizens, DISH was observed in unusual high numbers at a relatively young age. Some of the examined cases suggest that DISH may be a seriously incapacitating disorder when the more advanced stages of the disease have been reached. It is hypothesized that “a monastic way of life” can predispose to DISH. Present demographic trends in obesity and diabetes mellitus as potential co-factors for the development of DISH warrant further study to investigate its future prevalence
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