Journal articles: 'Parts per million (ppm)'

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Cody, Robert B. "Why Are We Still Reporting Mass Accuracy in Parts per Million (ppm)?" Journal of the American Society for Mass Spectrometry 31, no. 4 (March 18, 2020): 1004–5. http://dx.doi.org/10.1021/jasms.9b00150.

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Sunberg, Richard J. "A simple procedure to convert parts per million (ppm) to molarity (m)." Journal of Chemical Education 63, no. 8 (August 1986): 714. http://dx.doi.org/10.1021/ed063p714.

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Li, Libo, Rui-Biao Lin, Rajamani Krishna, Xiaoqing Wang, Bin Li, Hui Wu, Jinping Li, Wei Zhou, and Banglin Chen. "Efficient separation of ethylene from acetylene/ethylene mixtures by a flexible-robust metal–organic framework." Journal of Materials Chemistry A 5, no. 36 (2017): 18984–88. http://dx.doi.org/10.1039/c7ta05598f.

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Gibbs, Shawn G., John J. Lowe, Philip W. Smith, and Angela L. Hewlett. "Gaseous Chlorine Dioxide as an Alternative for Bedbug Control." Infection Control & Hospital Epidemiology 33, no. 5 (May 2012): 495–99. http://dx.doi.org/10.1086/665320.

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Objective.This study evaluated the efficacy of gaseous chlorine dioxide (ClO2) for extermination of bedbugs (Cimex lectularius and Citnex hemipterus).Background.Bedbugs have received attention because of recent outbreaks. Bedbug eradication is difficult and often requires a time-consuming multifaceted approach.Setting.Laboratory and hospital room.Methods.Bedbugs were exposed to concentrations of ClO2 of 362, 724, and 1,086 parts per million (ppm) in an exposure chamber. Bedbug mortality was then evaluated. The ability of ClO2 to penetrate various spaces in a hospital room was evaluated using Bacillus atropheus as a surrogate organism.Results.Concentrations of 1,086 and 724 ppm of ClO2 yielded 100% bedbug mortality assessed immediately after exposure. Live young were not observed for any eggs exposed to ClO2 gas. ClO2 at a concentration of 362 ppm for 1,029 parts per million hours (ppm-hours) achieved 100% mortality 6 hours after exposure. A ClO2 concentration of 362 ppm for 519 ppm-hours had 100% mortality 18 hours after exposure. Up to a 6-log reduction in B. atropheus spores was achieved using similar concentrations of ClO2 in a hospital room, indicating that the concentrations needed to kill bedbugs can be achieved throughout a hospital room.Conclusions.ClO2 is effective at killing bedbugs in the laboratory, and similar concentrations of ClO2 gas can be achieved in a hospital room. ClO2 can be removed from the room without residuals.

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Mody, I., and J. J. Miller. "Levels of hippocampal calcium and zinc following kindling-induced epilepsy." Canadian Journal of Physiology and Pharmacology 63, no. 2 (February 1, 1985): 159–61. http://dx.doi.org/10.1139/y85-028.

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Hippocampal calcium and zinc content was determined using atomic absorption spectrophotometry in control and commissural-kindled rats. In animals exhibiting 5–10 consecutive motor seizures hippocampal calcium was slightly elevated (356.7 parts per million (ppm), dry weight) but not significantly different from controls (329.8 ppm), whereas the amount of zinc was significantly higher (101.6 ppm) than in nonstimulated animals (88.3 ppm). These results are indicative of certain pathophysiological changes in kindled hippocampi, most likely localized to the granule cells of the dentate gyrus where the bulk of hippocampal zinc is confined.

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Uozumi, Yasuhiro, Anggi Eka Purta, Shun Ichii, and Aya Tazawa. "C−H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex." Synlett 31, no. 16 (July 24, 2020): 1634–38. http://dx.doi.org/10.1055/s-0040-1707213.

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A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25–100 mol ppm of chlorido[(2-phenyl-κ-C 2)-9-phenyl-1,10-phenanthroline-κ2-N,N′]palladium(II) NNC-pincer complex, K2CO3, and pivalic acid in N,N-dimethylacetamide afforded the corresponding 2- or 5-arylated thiophenes in good to excellent yields. A combination of the present C–H arylation and Hiyama coupling with the same NNC-pincer complex provides an efficient synthesis of unsymmetrical 2,5-thiophenes with catalyst loadings at mol ppm levels.

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Fritz, Ronald D., and Yumin Chen. "Characterizing the Distribution of Ppm Gluten in Gluten Free Oatmeal Servings Contaminated with a Wheat Kernel." Journal of Food Research 6, no. 5 (August 25, 2017): 92. http://dx.doi.org/10.5539/jfr.v6n5p92.

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Oats are often contaminated with rogue kernels of gluten-containing grains like wheat, barley and rye. When producing gluten free oatmeal, possessing an understanding of the consequences of this possibility is prudent, as labeling requirements specify a maximum amount of gluten in terms of ‘parts per million’ (ppm) gluten. Variation in contaminant kernels, along with variation due to measurement itself though, can result in a wide range of possible ppm gluten outcomes in contaminated servings. This research pursues characterization of this variability, highlighting contributors to it, doing so by quantifying distributional outcomes of ppm gluten in wheat kernel contaminated servings. This is done via statistical simulation of wheat kernel contaminated servings, done for a collection of wheat types and incorporating various measurement influences. Results indicate substantial variability in ppm gluten per serving for a given wheat type, as well as between them, with this being compounded by the measurement task itself.

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Kosovichev, Alexander G., and Klaus G. Strassmeier. "Joint Discussion 8 Solar and stellar activity cycles." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 271–72. http://dx.doi.org/10.1017/s174392130701054x.

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The solar magnetic field and its associated atmospheric activity exhibits periodic variations on a number of time scales. The 11-year sunspot cycle and its underlying 22-year magnetic cycle are, besides the 5-minute oscillation, the most widely known. Amplitudes and periods range from a few parts per million (ppm) and 2–3 minutes for p-modes in sunspots, a few 10 ppm and 10 minutes for the granulation turn around, a few 100 ppm and weeks for the lifetime of plages and faculae, 1000 ppm and 27 days for the rotational signal from spots, to the long-term cycles of 90 yr (Gleissberg cycle), 200 - 300 yr (Wolf, Spörer, Maunder minima), 2,400 yr from 14C tree-ring data, and possibly in excess of 100,000 yr.

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Turki Abdullah Aljalisi, Mohamed Hussein Madkour, Mohamed Mo, Turki Abdullah Aljalisi, Mohamed Hussein Madkour, Mohamed Mo. "Verifying the effective application of the HACCP system in some bottled water plants in the Eastern Province of the Kingdom of Saudi Arabia: التحقق من التطبيق الفعال لنظام الهاسب في بعض مصانع المياه المعبأة في المنطقة الشرقية بالمملكة العربية السعودية." Journal of agricultural, environmental and veterinary sciences 5, no. 2 (June 29, 2021): 64–48. http://dx.doi.org/10.26389/ajsrp.r100121.

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This study aims to verify the efficiency and effectiveness of applying the HACCP system in bottled water factories. A comparison was made between the factories that implement the HACCP system and the factories that do not implement the HACCP system. In this research، the chemical and bacteriological properties of bottled drinking water in the Eastern Province of the Kingdom of Saudi Arabia were studied. The pH، dissolved solids، nitrates، and fluoride were analyzed. Total coliforms، faecal coliforms، Escherichia coli، and pseudomonas. The results of the chemical analyzes indicated that they are in compliance with the standard limits stipulated in the Saudi Standard for Bottled Drinking Water, where the results of the chemical analysis of the factories were not applied to the HACCP system until the pH ranges between (6-7، 7). 71)، total dissolved solids (122-239) ppm، Nitrates (0،01-2،77) ppm، fluoride (0.01-1.05) ppm، while the results of factories applying HACCP system As follows: pH (6،93-7،34) total dissolved salts (168-197) parts per million، nitrates (0،004-0،42) parts per million، Fluoride (0.94-1،2) ppm. The microbiological results were within the limits allowed for the factories not applied and applied to HACCP system except in one sample for the factories that apply the HACCP system، as the analyzes showed a non-conformity to one of the water samples analyzed due to the presence of pseudomonas bacteria. The researcher presented appropriate recommendations and solutions، including continuous chemical and microbiological analyzes، while checking and reviewing HACCP system in bottled water factories.

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Punzalan, Kurt Brian Daine B., Franz Kevin B. Manalo, and Emmanuel A. Florido. "Ammonia Gas Detection Using Fabricated Zinc Oxide (ZnO) Nanoparticles on Glass Tube Substrates." Key Engineering Materials 775 (August 2018): 266–71. http://dx.doi.org/10.4028/www.scientific.net/kem.775.266.

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This study aimed to determine the ammonia (NH3) gas sensing ability of zinc oxide (ZnO) films deposited on glass tube substrates via successive ionic layer adsorption and reaction (SILAR) technique. The fabricated films were annealed at different temperatures. The sensor films were exposed to different volumes of ammonium hydroxide (NH4OH), converted to parts per million (ppm). The change in voltage from concentrations 595ppm up to 1189ppm exhibited a linear trend. However, no trend was revealed in concentrations 2378ppm and 3964ppm due to film saturation. Results showed that the films annealed at 250 °C, 300 °C, 350 °C, and 400 °C presented sensitivities of 2.7×10-4V/ppm, 1.0×10-4V/ppm, 2.3×10-4V/ppm, and 1.5×10-4V/ppm with R2values of 0.997, 0.994, 0.904, 0.999 and resolutions of 3.7 ppm/mV, 9.9 ppm/mV, 4.4 ppm/mV, and 6.6 ppm/mV, respectively. Furthermore, this research study had proven that high quality gas sensors may be fabricated at a lower cost.

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Tibballs, J., M. Hochmann, B. Carter, and A. Osborne. "An Appraisal of Techniques for Administration of Gaseous Nitric Oxide." Anaesthesia and Intensive Care 21, no. 6 (December 1993): 844–47. http://dx.doi.org/10.1177/0310057x9302100617.

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Gaseous nitric oxide (NO) is a potent selective pulmonary vasodilator. When mixed with O2 for more than 10-15 minutes it forms toxic amounts of nitrogen dioxide (NO2). We describe two techniques to administer 20 parts per million (ppm) during mechanical ventilation. A technique using flows of NO and O2 at low pressure to drive a Siemens Servo 900C ventilator provided a constant inspired concentration of NO. Another technique in which NO was added to the inspiratory limb of a Siemens Servo 900C ventilator driven by high pressure oxygen provided a highly variable concentration (9-53 ppm) of inspired NO.

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Ranganathan, S., and B. S. Narasinga Rao. "Development of a Simple Field Kit for Monitoring Iron in Fortified Salt." Food and Nutrition Bulletin 14, no. 1 (March 1992): 1–2. http://dx.doi.org/10.1177/156482659201400104.

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One practical way to control iron-deficiency anaemia is to fortify edible salt with iron. Effective implementation of a programme for producing and distributing iron-fortified salt requires regular monitoring of edible salt for iron, particularly at the retail sales and household levels. A simple, inexpensive (10 rupees) field kit was developed for this purpose. No glassware has to be carried, and reagents are supplied in the form of tablets. It is possible to detect iron fevers as low as 50 parts per million (ppm) and as high as 1,000 ppm. One kit can be used to test 200 salt samples.

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Ravichandar, D., Thangavel Balusamy, and K. Bommannan Nagashanmugam. "Reducing UT Rejections in Cr-Mo and High Mn Steels by Controlling Hydrogen and Optimising Superheat." Applied Mechanics and Materials 591 (July 2014): 38–42. http://dx.doi.org/10.4028/www.scientific.net/amm.591.38.

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JSW Steel Limited, Salem Works (JSWSL), is an integrated steel plant, having a production capacity of 1.0 mtpa (million tons per annum) of high-grade automotive special steels. At JSWSL, hydrogen induced cracks and center unsoundness contribute more to UT (Ultrasonic testing) rejections in chrome-molybdenum (Cr-Mo) and high manganese grade steels. Hydrogen induced cracks was controlled by increasing argon flow rate from 3-4 Nm3 to 7-9 Nm3 during vacuum degassing. Vigorous purging led to a reduction in hydrogen levels from around 2 ppm (parts per million) to less than 1.5 ppm. Center unsoundness was controlled through optimising superheats in tundish. Data of trial heats revealed that, UT rejections were more in heats cast with superheat levels more than 35°C. Based on the data obtained from trial heats superheat was optimised to 25-35°C for both Cr-Mo and high manganese steels. The present paper discusses the measures taken to reduce UT rejections in these grades.KeywordsJSWSL, Cr-Mo, High Mn steels, UT rejections, superheat, hydrogen induced cracks, center unsoundness, vacuum degassing, continuous casting.

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Bunce, Hubert W. F. "Empirical estimates of loss of value in a second growth coniferous forest related to changes in fluoride emissions." Forestry Chronicle 69, no. 1 (February 1, 1993): 71–74. http://dx.doi.org/10.5558/tfc69071-1.

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Empirical values for western hemlock in a forest surrounding an aluminum smelter are given. A reduced rate of growth loss is suggested to relate to a reduction in the level of emission of fluoride from the smelter. From 1971 to 1980, the trees showed reduced growth when emissions were 3.7 tonnes per day and the foliage fluoride content was 74 parts per million (ppm). An emission level of 1.4 tonnes/day produced foliage containing 19 ppm fluoride and no height growth reduction. From 1972 to 1981, 2.6 years of growth on 895 hectares were estimated to be lost which were equal to 26 993 cubic metres (m3) with a value of $18,000/yr. (1986 dollars). Key words: Growth reduction, value loss, second growth, western hemlock, air emissions, fluoride, aluminum smelter, British Columbia

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Cowles, Richard S. "Modeling the Effectiveness of Bifenthrin for Reducing Populations of Japanese and Oriental Beetle Larvae in Nursery Containers." Journal of Environmental Horticulture 21, no. 2 (June 1, 2003): 78–81. http://dx.doi.org/10.24266/0738-2898-21.2.78.

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Abstract Preplant potting mix incorporation of Talstar 0.2G (bifenthrin) can prevent root weevil and white grub infestations in container-grown nursery crops. Analysis of bifenthrin residues from potting media aged under northern nursery conditions indicated that this insecticide has a half-life of at least 3 years, irrespective of medium composition. Dose-response tests of bifenthrin for controlling Japanese and oriental beetle larvae indicated that the LD50 for these species is approximately 1.1 and 1.7 parts per million (ppm), respectively. These data suggest that >95% larval mortality of these scarab species can be expected up to three years following treatment of media with 10 ppm bifenthrin, and >99.9% larval mortality is expected for at least three years following treatment of media with 20 ppm bifenthrin.

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Packwood, R., M. W. Phaneuf, V. Weatherall, and I. Bassignana. "Analysis of completed commercial semiconductors using EPMA." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 502–3. http://dx.doi.org/10.1017/s0424820100164970.

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The development of specialized analytical instruments such as the SIMS, XPS, ISS etc., all with truly incredible abilities in certain areas, has given rise to the notion that electron probe microanalysis (EPMA) is an old fashioned and rather inadequate technique, and one that is of little or no use in such high technology fields as the semiconductor industry. Whilst it is true that the microprobe does not possess parts-per-billion sensitivity (ppb) or monolayer depth resolution it is also true that many times these extremes of performance are not essential and that a few tens of parts-per-million (ppm) and a few tens of nanometers depth resolution is all that is required. In fact, the microprobe may well be the second choice method for a wide range of analytical problems and even the method of choice for a few.The literature is replete with remarks that suggest the writer is confusing an SEM-EDXS combination with an instrument such as the Cameca SX-50. Even where this confusion does not exist, the literature discusses microprobe detection limits that are seldom stated to be as low as 100 ppm, whereas there are numerous element combinations for which 10-20 ppm is routinely attainable.

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Monico-Pifarre, Amalia, and Maria Xirau-Vayreda. "Monitoring Residues of Carbendazim (Applied as Benomyl) and Thiabendazole in Wellspur Apples." Journal of AOAC INTERNATIONAL 70, no. 3 (May 1, 1987): 596–98. http://dx.doi.org/10.1093/jaoac/70.3.596.

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Abstract Residues of benomyl (determined as carbendazim, widely accepted as MBC) and of thiabendazole in Wellspur apples were monitored after the apples were treated postharvest by immersion in a bath with each of the fungicides separately and stored under refrigeration. Whole fruit and pulp analyses were conducted over the period beginning 1 day after treatment and lasting up to 200 days afterwards. Under the conditions described, both benomyl (expressed as parts per million of carbendazim) and thiabendazole were found in the fruits in the following average amounts: 0.44 ± 0.03 and 0.11 ± 0.03 ppm benomyl (as carbendazim) in whole fruit and in pulp, respectively; 0.98 ± 0.10 and 0.39 ± 0.10 ppm thiabendazole in whole fruit and in pulp, respectively.

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Sangster, Jodi Lynn, Andrew Nelson, and Shannon L. Bartelt-Hunt. "THE OCCURRENCE OF LEAD IN SOIL AND VEGETABLES AT A COMMUNITY GARDEN IN OMAHA, NEBRASKA." International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship 7, no. 1 (May 30, 2012): 62–68. http://dx.doi.org/10.24908/ijsle.v7i1.4231.

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Abstract – Lead is a persistent and ubiquitous pollutant in urban environments and is of significant importance to public health. Elevated lead concentrations in soil may be due to the use of lead-based paints, emissions from the combustion of leaded gasoline, industrial emissions, waste incineration, and pesticide application. One potential pathway for exposure to lead can be consumption of produce grown in lead-contaminated soil. This may be of increasing concern as urban community gardens experience a resurgence in popularity and demand for locally grown produce increases. For this project, soil and vegetable samples were collected from a community garden with known soil lead contamination. Soil and vegetable samples were evaluated for total lead content using atomic absorption spectroscopy. The concentrations of lead measured in soil ranged from 4 to 574 parts per million (ppm), with an average lead concentration in the growing beds of 128.4 ppm and in the OmaGro compost of 31.5 ppm. Additionally, lead was present in vegetable samples at or below 16.25 ppm.

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Alpsoy, Lokman, Elif Kotan, Abdulgani Tatar, and Guleray Agar. "Protective effects of selenium against sister chromatid exchange induced by AFG 1 in human lymphocytes in vitro." Human & Experimental Toxicology 30, no. 6 (July 14, 2010): 515–19. http://dx.doi.org/10.1177/0960327110377523.

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Aflatoxins have been shown to be hepatotoxic, carcinogenic, mutagenic and teratogenic to different species of animals. Besides, at low concentrations, Selenium (Se4+) is antimutagenic and anticarcinogenic while it is toxic, mutagenic and carcinogenic at high concentrations. In this study, we aimed to evaluate the effect of Se4+ against aflatoxin GAFG1 (AFG1) on blood cultures in relation to induction of sister chromatid exchange (SCE). The results showed that at 0.4 and 0.8 parts per million (ppm) concentration of AFG1, the frequency of SCE increased in cultured human lymphocytes. When different concentration of Se4+ (0.08 and 8 ppm) were added to AFG1, the frequencies of SCE decreased. Howewer, when 800 ppm concentration of Se4+ together with 0.08 ppm AFG1 were added to cell division inhibited in the cultures. Results suggested that Se4+ could effectively inhibit AFG1-induced SCE. Besides, the protective role of Se4+ against AFG1-induced SCE is probably related to its doses.

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Stewart, Christopher, Noel Solomons, Ivan Mendoza, Sandy May, and Glen Maberly. "Salt Iodine Variation within an Extended Guatemalan Community: The Failure of Intuitive Assumptions." Food and Nutrition Bulletin 17, no. 3 (September 1996): 1–4. http://dx.doi.org/10.1177/156482659601700308.

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Guatemalan law mandates an iodine concentration from 30 to 700 parts per million (ppm) in all table salt offered in local commerce. Forty-four specimens of salt were collected in urban and rural sectors of a county on the outskirts of the capital of Guatemala and analysed for their iodine content by an iodate titration method. The concentrations ranged from 1 to 117 ppm, (mean ± SD 26.6 ± 21.7 ppm, median 24 ppm). Salt samples with iodine in both the adequate and the inadequate ranges were found in each of five subjurisdictions (township and four hamlets), and the median concentration was equivalent at all sites, without an urban-to-rural gradient. Similarly, the mandated iodine concentration was no more likely to be found in salt packaged under a brand name with a commercial label than in salt in a plain, unlabelled package. The findings place in relief the continuing difficulties in Guatemala in the effort to provide a universally protective level of iodine in table salt.

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Higgins, John A., Andrei V. Kurbatov, Nicole E. Spaulding, Ed Brook, Douglas S. Introne, Laura M. Chimiak, Yuzhen Yan, Paul A. Mayewski, and Michael L. Bender. "Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica." Proceedings of the National Academy of Sciences 112, no. 22 (May 11, 2015): 6887–91. http://dx.doi.org/10.1073/pnas.1420232112.

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Here, we present direct measurements of atmospheric composition and Antarctic climate from the mid-Pleistocene (∼1 Ma) from ice cores drilled in the Allan Hills blue ice area, Antarctica. The 1-Ma ice is dated from the deficit in 40Ar relative to the modern atmosphere and is present as a stratigraphically disturbed 12-m section at the base of a 126-m ice core. The 1-Ma ice appears to represent most of the amplitude of contemporaneous climate cycles and CO2 and CH4 concentrations in the ice range from 221 to 277 ppm and 411 to 569 parts per billion (ppb), respectively. These concentrations, together with measured δD of the ice, are at the warm end of the field for glacial–interglacial cycles of the last 800 ky and span only about one-half of the range. The highest CO2 values in the 1-Ma ice fall within the range of interglacial values of the last 400 ka but are up to 7 ppm higher than any interglacial values between 450 and 800 ka. The lowest CO2 values are 30 ppm higher than during any glacial period between 450 and 800 ka. This study shows that the coupling of Antarctic temperature and atmospheric CO2 extended into the mid-Pleistocene and demonstrates the feasibility of discontinuously extending the current ice core record beyond 800 ka by shallow coring in Antarctic blue ice areas.

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Sunmonu, TO, and OB Oloyede. "Performance and haematological indices in rats exposed to monocrotophos contamination." Human & Experimental Toxicology 29, no. 10 (March 1, 2010): 845–50. http://dx.doi.org/10.1177/0960327110363441.

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Monocrotophos is an organophosphate pesticide used in agriculture to control insect pests. Changes in performance and haematological parameters (such as packed cell volume, white blood cells, neutrophils, eosinophils and lymphocytes) were used to assess the effect of the pesticide on rats chronically exposed to 12.5 parts per million (ppm), 25 ppm, 50 ppm, 100 ppm and 200 ppm for 10 days, while the control rats were placed on borehole water. Administration of the pesticide to the animals resulted in several physical deteriorations including appearance and agility. A significant reduction (p < .05) was observed in the weight gained by rats while the liver-to-body weight ratio increased significantly (p < .05) as the level of exposure to monocrotophos increased. Whereas packed cell volume, white blood cells and lymphocytes increased significantly (p < .05), neutrophils and eosinophils counts reduced significantly (p < .05) as the concentration of monocrotophos in the drinking water increased. Overall, the data indicated that exposure to monocrotophos portends serious consequences on the performance and haematological parameters of rats.

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Crespo, Jorge, Martin Reich, Fernando Barra, Juan José Verdugo, Claudio Martínez, Mathieu Leisen, Rurik Romero, Diego Morata, and Carlos Marquardt. "Occurrence and Distribution of Silver in the World-Class Río Blanco Porphyry Cu-Mo Deposit, Central Chile." Economic Geology 115, no. 8 (October 26, 2020): 1619–44. http://dx.doi.org/10.5382/econgeo.4778.

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Abstract Porphyry Cu-Mo deposits (PCDs) are the world’s major source of Cu, Mo, and Re and are also a significant source of Au and Ag. Here we focus on the world-class Río Blanco PCD in the Andes of central Chile, where Ag is a by-product of Cu mining. Statistical examination of an extensive multielemental inductively coupled plasma-mass spectrometry data set indicates compositional trends at the deposit scale, including Ag-Cu (r = 0.71) and Ag-In (r = 0.53) positive correlations, which relate to Cu-Fe sulfides and Cu sulfosalts in the deposit. Silver is primarily concentrated in Cu ores in the central core of the deposit, and significant variations in the Ag concentration are related to the different hydrothermal alteration types. The concentration of Ag is highest in the potassic core (avg 2.01 ppm) and decreases slightly in the gray-green sericite (phyllic) zone (avg 1.72 ppm); Ag is lowest in the outer propylitic alteration zone (avg 0.59 ppm). Drill core samples from major hydrothermal alteration zones were selected for in situ analysis of Ag and associated elements in sulfide and sulfosalt minerals. To ensure representativeness, sample selection considered the spatial distribution of the alteration types and ore paragenesis. Chalcopyrite is the most abundant Cu sulfide in Río Blanco, with Ag concentration that ranges from sub-parts per million levels to hundreds of parts per million. The highest concentration of Ag in chalcopyrite is associated with the high-temperature potassic alteration stage. Bornite is less abundant than chalcopyrite but has the highest Ag concentration of all studied sulfides, ranging from hundreds of parts per million up to ~1,000 ppm. The Ag concentration in bornite is higher in lower-temperature alteration assemblages (moderate gray-green sericite), opposite to the behavior of Ag in chalcopyrite. Pyrite has the lowest Ag content, although concentrations of other critical elements such as Co, Ni, and Au may be significant. The highest Ag concentrations, i.e., thousands of parts per million up to weight percent levels, were detected in late-stage Cu sulfosalts (enargite, tennantite, and tetrahedrite). The Ag content in these sulfosalts increases with increasing Sb concentrations, from the Sb-poor enargite to the Sb-rich tetrahedrite. The earliest Ag mineralization event is related to the potassic alteration stage represented by early biotite and transitional early biotite-type veinlets and where the predominant sulfides are chalcopyrite and bornite. Silver mineralization during this stage was predominantly controlled by crystallization of Cu-Fe sulfides. The second Ag mineralization event at Río Blanco is associated with the transitional Cu mineralization stage, which is represented by the gray-green sericite alteration (C-type veinlets). In this alteration type, Ag was partitioned preferentially into chalcopyrite, bornite, and to a lesser extent pyrite. The last Ag mineralization event is related to the late quartz-sericite alteration stage, characterized by D- and E-type veinlets with pyrite-chalcopyrite and enargite-tennantite-tetrahedrite. Our data indicate that Ag was associated with several Cu mineralization episodes at Río Blanco, with Ag concentration apparently controlled by cooling, changes in pH, fO2 and fS2 of the hydrothermal fluids, and the intensity of alteration. Overall, our results provide information on critical metal partitioning between sulfides, plus the distribution of critical element resources at the deposit scale. Knowledge of the mineralogical occurrence of critical metals in PCDs is necessary to better assess their resources and evaluate the potential for their recovery.

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Krzempek, Karol, Krzysztof Abramski, and Michal Nikodem. "Kagome Hollow Core Fiber-Based Mid-Infrared Dispersion Spectroscopy of Methane at Sub-ppm Levels." Sensors 19, no. 15 (July 31, 2019): 3352. http://dx.doi.org/10.3390/s19153352.

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In this paper, we demonstrate the laser-based gas sensing of methane near 3.3 µm inside hollow-core photonic crystal fibers. We exploit a novel anti-resonant Kagome-type hollow-core fiber with a large core diameter (more than 100 µm) which results in gas filling times of less than 10 s for 1.3-m-long fibers. Using a difference frequency generation source and chirped laser dispersion spectroscopy technique, methane sensing with sub-parts-per-million by volume detection limit is performed. The detection of ambient methane is also demonstrated. The presented results indicate the feasibility of using a hollow-core fiber for increasing the path-length and improving the sensitivity of the mid-infrared gas sensors.

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Mosier-Boss, P. A., and S. H. Lieberman. "Detection of Nitrate and Sulfate Anions by Normal Raman Spectroscopy and SERS of Cationic-Coated, Silver Substrates." Applied Spectroscopy 54, no. 8 (August 2000): 1126–35. http://dx.doi.org/10.1366/0003702001950922.

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The use of normal Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) of cationic-coated, silver substrates to detect nitrate and sulfate ions in aqueous environments is examined. For normal Raman spectroscopy using near-infrared excitation, a linear concentration response was observed with detection limits of 260 and 440 ppm for nitrate and sulfate, respectively. Detection limits in the low parts-per-million concentration range for these anions are achieved by using cationic-coated, silver SERS substrates. Adsorption of the anions on the cationic-coated SERS substrates is described by a Frumkin isotherm.

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Otieno, Jeremiah, Przemysław Kowal, and Jacek Mąkinia. "Monitoring Lead Concentration in the Surrounding Environmental Components of a Lead Battery Company: Plants, Air and Effluents—Case Study, Kenya." International Journal of Environmental Research and Public Health 19, no. 9 (April 25, 2022): 5195. http://dx.doi.org/10.3390/ijerph19095195.

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Lead (Pb) pollution from smelters and lead–acid battery has become a serious problem worldwide owing to its toxic nature as a heavy metal. Stricter regulations and monitoring strategies have been formulated, legislated and implemented in various parts of the world on heavy metal usage. Developed countries such as the USA and in Europe largely operate within the set standards, however, developing countries such as Kenya, Nigeria and India, with limited regulatory capacity, resources and sufficient data, face poor Pb waste management and exposure of the population to health risks. This study assessed the pollution concerns from Associated Battery Manufacturers (East Africa) Limited (ABM), located in the Nairobi Industrial Area in Kenya. Samples of air, extracts from plants (leaves) and factory wastewaters were taken from different operations units, prepared and analysed with Atomic Absorption Spectrometry (AAS). Pb traces remained fairly controlled with averages of 1.24 ± 0.42 parts per million (ppm), 1.21 ± 0.02 ppm and 0.29 ± 0.01 ppm in the air, plant extracts and effluents, respectively. The conducted research shows that the obtained lead concentrations in the air, wastewater and surrounding plants exceeded the recommended standards, and are potentially harmful not only to workers, but also to the surrounding villages.

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Otieno, Jeremiah, Przemysław Kowal, and Jacek Mąkinia. "Monitoring Lead Concentration in the Surrounding Environmental Components of a Lead Battery Company: Plants, Air and Effluents—Case Study, Kenya." International Journal of Environmental Research and Public Health 19, no. 9 (April 25, 2022): 5195. http://dx.doi.org/10.3390/ijerph19095195.

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Lead (Pb) pollution from smelters and lead–acid battery has become a serious problem worldwide owing to its toxic nature as a heavy metal. Stricter regulations and monitoring strategies have been formulated, legislated and implemented in various parts of the world on heavy metal usage. Developed countries such as the USA and in Europe largely operate within the set standards, however, developing countries such as Kenya, Nigeria and India, with limited regulatory capacity, resources and sufficient data, face poor Pb waste management and exposure of the population to health risks. This study assessed the pollution concerns from Associated Battery Manufacturers (East Africa) Limited (ABM), located in the Nairobi Industrial Area in Kenya. Samples of air, extracts from plants (leaves) and factory wastewaters were taken from different operations units, prepared and analysed with Atomic Absorption Spectrometry (AAS). Pb traces remained fairly controlled with averages of 1.24 ± 0.42 parts per million (ppm), 1.21 ± 0.02 ppm and 0.29 ± 0.01 ppm in the air, plant extracts and effluents, respectively. The conducted research shows that the obtained lead concentrations in the air, wastewater and surrounding plants exceeded the recommended standards, and are potentially harmful not only to workers, but also to the surrounding villages.

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COELHO JUNIOR, ALOISIO, and JOSE R. P. PARRA. "Effect of Carbon dioxide (CO2) on mortality and reproduction of Anagasta kuehniella (Zeller 1879), in mass rearing, aiming at the production of Trichogramma spp." Anais da Academia Brasileira de Ciências 85, no. 2 (June 2013): 823–31. http://dx.doi.org/10.1590/s0001-37652013000200021.

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Eggs of Anagasta kuehniella (Zeller 1879) are widely used for mass rearing of Trichogramma spp. and other parasitoids and predators, largely commercialized in many countries. The aim of this study is to evaluate the effect of carbon dioxide (CO2) originated from larval metabolism on the biological parameters of A. kuehniella. For that purpose, we assess the production of carbon dioxide (CO2) per rearing tray of A. kuehniella and the effect of CO2 on the viability of egg-to-adult period and oviposition of A. kuehniella. Results allow to estimate that a rearing tray, containing 10,000 larvae between the 4th and 5th instars, produces an average of 30.67 mL of CO2 per hour. The highest egg production of A. kuehniella was obtained when the larvae were kept in rooms with lower concentration of CO2 (1,200 parts per million - ppm), producing 23% more eggs than in rooms with higher CO2 concentrations. In rooms with high density of trays (70 trays/room), CO2 concentration exceeded 4,400 ppm. The viability of the egg-to-adult period was not influenced by carbon dioxide.

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Wales, Michael, Eminet Gebremichael, Xiao Wang, Elisabeth Perea, Palitha Jayaweera, and Indira Jayaweera. "Flue Gas Desulfurization (FGD) Wastewater Treatment Using Polybenzimidazole (PBI) Hollow Fiber (HF) Membranes." Membranes 11, no. 6 (June 5, 2021): 430. http://dx.doi.org/10.3390/membranes11060430.

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Polybenzimidazole (PBI) hollow fiber membranes were used to treat flue gas desulfurization (FGD) wastewater (WW) from a coal fired power plant. Membranes were tested using both single salt solutions and real FGD WW. The PBI membranes showed >99% rejection for single salt solutions of NaCl, MgCl2, CaSO4, and CaCl2 at approximately 2000 PPM (parts per million). The membranes also showed >97% rejection for FGD WW concentrations ranging from 6900 to 14,400 PPM total dissolved solids (TDS). The pH of the FGD WW was adjusted between 3.97–8.20, and there was an optimal pH between 5.31 and 7.80 where %rejection reached a maximum of >99%. The membranes were able to operate stably up to 50 °C, nearly doubling the water flux as compared to room temperature, and while maintaining >98% salt rejection.

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Vengarai Jagannathan, Badrinath, Steven Kitchens, Paul Priyesh Vijayakumar, Stuart Price, and Melissa Morgan. "Potential for Bacteriophage Cocktail to Complement Commercial Sanitizer Use on Produce against Escherichia coli O157:H7." Microorganisms 8, no. 9 (August 29, 2020): 1316. http://dx.doi.org/10.3390/microorganisms8091316.

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The increasing concern for food safety has created a need to evaluate novel techniques to eliminate or control pathogens, resulting in safe food. In this study, four bacteriophages of bovine origin, specific to E. coli O157:H7, were successfully isolated and characterized. A microplate reader assay demonstrated the efficacy of the bacteriophage (phage) cocktail against E. coli O157:H7 resulting in a significant reduction (p < 0.01) in the target pathogen population. The phage cocktail demonstrated significant efficacy (p < 0.05) against E. coli O157:H7 in the presence of the most utilized sanitizers in the United States, namely 100 parts per million (ppm) free chlorine and 100-ppm peroxyacetic acid. Survival in the sanitizer concentrations demonstrates the potential use of phage cocktail and sanitizer synergistically to enhance sanitation operations in the food industry.

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Petrov, Dmitry V. "Features of Measuring Low CO Concentrations in N2-Containing Mixtures at Different Temperatures Using Spontaneous Raman Spectroscopy." Applied Spectroscopy 75, no. 1 (October 8, 2020): 81–86. http://dx.doi.org/10.1177/0003702820957009.

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Raman spectroscopy is a promising tool for combustion processes optimization, due to the possibility of rapid determination of the exhaust gases composition. An important gas component in this task is carbon monoxide whose emission limits vary from 100 to 200 parts per million (ppm), depending on the heat generator technology. However, for the correct determination of its concentration from the sample Raman spectrum, it is necessary to take into account the contribution of nitrogen lines intensity due to their mutual overlap. This paper discusses a technique for deriving carbon monoxide intensity based on fitting the nitrogen spectrum at various temperatures. It is shown that ignoring the Herman–Wallis factors in the fitting procedure lead to an additional measurement error, which increases with temperature and exceeds 350 ppm at T = 1800 K.

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Boyle, Sean Michael, Gabor Bartha, John Lyle, Jason Harris, Josette Northcott, Dan Norton, Rachel Marty Pyke, et al. "Abstract 5163: A high sensitivity, tumor-informed liquid biopsy platform, designed to detect minimal residual disease at part per million resolution." Cancer Research 82, no. 12_Supplement (June 15, 2022): 5163. http://dx.doi.org/10.1158/1538-7445.am2022-5163.

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Abstract Tumor-informed liquid biopsy approaches have proven promising for detecting minimal residual disease (MRD) and recurrence of cancer following surgical resection or other therapy. However, current liquid biopsy MRD assays typically detect ctDNA in a range above 30 to 300 parts per million (PPM), leaving a significant fraction of MRD cases undetected, particularly soon after surgery and in early stage cancers where ctDNA can be at very low levels. To address this, we have developed NeXT Personal™, a tumor-informed liquid biopsy assay that achieves sensitivity down to 1 PPM, therefore enabling earlier detection of MRD and recurrence. NeXT Personal leverages tumor/normal whole genome sequencing to design personalized MRD liquid biopsy panels for each patient. The panel is composed of >1,200 somatic tumor variants enabling higher sensitivity MRD detection in plasma through tracking of larger numbers of high quality and lower noise variants. This allows the platform to achieve high sensitivity across cancer types and stages, including early stage cancers and low mutational burden tumors, utilizing ~4 mL of plasma. Two independent methods were used to establish utility and performance: a proprietary cell-line media system, and well-characterized matched tumor-normal-plasma patient samples. Samples were serially diluted to <1 PPM, with replicates used to confirm performance. Digital droplet polymerase chain reaction (ddPCR) was used to orthogonally validate platform performance to the limit of detection (LOD) of ddPCR. Characterization of MRD LOD in three cell-line media systems, HCC1143, HCC38, and HCC1937, yielded accurate and reproducible detection of signal across a broad range of concentrations, to a lower limit of 1-2 PPM. We then used our platform to characterize MRD LOD in a set of serially diluted patient samples, demonstrating sensitivity down to as low as 1 PPM, with high specificity in normal control samples. Finally, we demonstrated the performance of NeXT Personal with matched tumor-normal-plasma patient samples (8 different cancer types, stages II-IV). In this series, NeXT Personal detected cancers down to 0.8 PPM with high specificity demonstrated across a set of healthy normal donor samples. We estimate that ~50% of the cases in this set of patients would not have been detected by other commercially available liquid biopsy MRD platforms. NeXT Personal achieved highly sensitive and specific MRD detection, reproducibly demonstrating a LOD down to 1 PPM in different cancer types and cell line dilutions, representing approximately 10 to 100 times higher sensitivity than other liquid biopsy MRD approaches. The high sensitivity of NeXT Personal potentially enables MRD detection across a broad variety of cancers and stages, including typically challenging early stage, low mutational burden, and low-shedding cancers. Citation Format: Sean Michael Boyle, Gabor Bartha, John Lyle, Jason Harris, Josette Northcott, Dan Norton, Rachel Marty Pyke, Fabio C. P. Navarro, Alexander Stram, Christian Haudenschild, Rose Santiago, Robin Li, Chris Nelson, Yelia Huo, Manju Chinnappa, Qi Zhang, Lloyd Hsu, John West, Richard O. Chen. A high sensitivity, tumor-informed liquid biopsy platform, designed to detect minimal residual disease at part per million resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5163.

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Dai, Jixiang, Yi Li, Hongbo Ruan, Zhuang Ye, Nianyao Chai, Xuewen Wang, Shuchang Qiu, Wei Bai, and Minghong Yang. "Fiber Optical Hydrogen Sensor Based on WO3-Pd2Pt-Pt Nanocomposite Films." Nanomaterials 11, no. 1 (January 8, 2021): 128. http://dx.doi.org/10.3390/nano11010128.

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In this paper, WO3-Pd2Pt-Pt nanocomposite films were deposited on a single mode fiber as the hydrogen sensing material, which changes its reflectivity under different hydrogen concentration. The reflectivity variation was probed and converted to an electric signal by a pair of balanced InGaAs photoelectric detectors. In addition, the performance of the WO3-Pd2Pt-Pt composite film was investigated under different optical powers, and the irrigating power was optimized at 5 mW. With the irrigation of this optical power, the hydrogen sensitive film exhibits quick response toward 100 ppm hydrogen in air atmosphere at a room temperature of 25 °C. The experimental results demonstrate a high resolution at 5 parts per million (ppm) within a wide range from 100 to 5000 ppm in air. This simple and compact sensing system can detect hydrogen concentrations far below the explosion limit and provide early alert for hydrogen leakage, showing great potential in hydrogen-related applications.

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Martin, Cory R., Ning Zeng, Anna Karion, Russell R. Dickerson, Xinrong Ren, Bari N. Turpie, and Kristy J. Weber. "Evaluation and environmental correction of ambient CO2 measurements from a low-cost NDIR sensor." Atmospheric Measurement Techniques 10, no. 7 (July 3, 2017): 2383–95. http://dx.doi.org/10.5194/amt-10-2383-2017.

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Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square error (RMSE) between ∼ 5 and 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had an RMSE of between 1.7 and 4.3 ppm for 1 min data. The median RMSE improved from 9.6 for off-the-shelf sensors to 1.9 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

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Dai, Jixiang, Yi Li, Hongbo Ruan, Zhuang Ye, Nianyao Chai, Xuewen Wang, Shuchang Qiu, Wei Bai, and Minghong Yang. "Fiber Optical Hydrogen Sensor Based on WO3-Pd2Pt-Pt Nanocomposite Films." Nanomaterials 11, no. 1 (January 8, 2021): 128. http://dx.doi.org/10.3390/nano11010128.

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In this paper, WO3-Pd2Pt-Pt nanocomposite films were deposited on a single mode fiber as the hydrogen sensing material, which changes its reflectivity under different hydrogen concentration. The reflectivity variation was probed and converted to an electric signal by a pair of balanced InGaAs photoelectric detectors. In addition, the performance of the WO3-Pd2Pt-Pt composite film was investigated under different optical powers, and the irrigating power was optimized at 5 mW. With the irrigation of this optical power, the hydrogen sensitive film exhibits quick response toward 100 ppm hydrogen in air atmosphere at a room temperature of 25 °C. The experimental results demonstrate a high resolution at 5 parts per million (ppm) within a wide range from 100 to 5000 ppm in air. This simple and compact sensing system can detect hydrogen concentrations far below the explosion limit and provide early alert for hydrogen leakage, showing great potential in hydrogen-related applications.

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Gregory, Timothy, Tu-Han Luu, Christopher D. Coath, Sara S. Russell, and Tim Elliott. "Primordial formation of major silicates in a protoplanetary disc with homogeneous 26Al/27Al." Science Advances 6, no. 11 (March 2020): eaay9626. http://dx.doi.org/10.1126/sciadv.aay9626.

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Understanding the spatial variability of initial 26Al/27Al in the solar system, i.e., (26Al/27Al)0, is of prime importance to meteorite chronology, planetary heat production, and protoplanetary disc mixing dynamics. The (26Al/27Al)0 of calcium-aluminum–rich inclusions (CAIs) in primitive meteorites (~5 × 10−5) is frequently assumed to reflect the (26Al/27Al)0 of the entire protoplanetary disc, and predicts its initial 26Mg/24Mg to be ~35 parts per million (ppm) less radiogenic than modern Earth (i.e., Δ′26Mg0 = −35 ppm). Others argue for spatially heterogeneous (26Al/27Al)0, where the source reservoirs of most primitive meteorite components have lower (26Al/27Al)0 at ~2.7 × 10−5 and Δ′26Mg0 of −16 ppm. We measured the magnesium isotope compositions of primitive meteoritic olivine, which originated outside of the CAI-forming reservoir(s), and report five grains whose Δ′26Mg0 are within uncertainty of −35 ppm. Our data thus affirm a model of a largely homogeneous protoplanetary disc with (26Al/27Al)0 of ~5 × 10−5, supporting the accuracy of the 26Al→26Mg chronometer.

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Williams, Ammon N., and Supathorn Phongikaroon. "Elemental Detection of Cerium and Gadolinium in Aqueous Aerosol Using Laser-Induced Breakdown Spectroscopy." Applied Spectroscopy 70, no. 10 (July 28, 2016): 1700–1708. http://dx.doi.org/10.1177/0003702816648327.

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Laser-induced breakdown spectroscopy (LIBS) was used to detect and measure the concentrations of Ce and Gd in aqueous aerosol solutions. A total of 36 standards, with concentrations of Ce and Gd ranging from 100 parts per million (ppm) to 10 000 ppm, were made to explore the relationship between them. In this study, a Collison nebulizer with an argon carrier gas was used to generate the aerosol droplets. For each liquid sample, ten repetitions of 200 laser shots each were recorded. The percent relative standard deviations (%RSD) were on an average of 7.5% between the ten different sample repetitions. Due to the close proximity of the Ce and Gd lines, it was challenging to identify peaks with low interferences. However, several lines were identified, calibration curves were constructed, and the best curves were generated using the 457.228 nm line for Ce and the 409.861 nm line for Gd. The LODs for these curves were calculated to be 209.7 ppm and 216.4 ppm for the Ce line and Gd line, respectively.

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Li, Chuanliang, Ligang Shao, Lijun Jiang, Xuanbing Qiu, Jilin Wei, and Weiguang Ma. "Simultaneous Measurements of CO and CO2 Employing Wavelength Modulation Spectroscopy Using a Signal Averaging Technique at 1.578 μm." Applied Spectroscopy 72, no. 9 (April 25, 2018): 1380–87. http://dx.doi.org/10.1177/0003702818766904.

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A resolved line pair was selected for simultaneous measurement of carbon monoxide (CO) and carbon dioxide (CO2) in the near-infrared (NIR) region. The spectral lines of CO and CO2 at 1.578 µm were measured by wavelength modulation spectroscopy (WMS)-2 f and the absorption was enhanced with a multipass absorption cell. The white noise was further reduced by averaging technology. The detection sensitivity (1σ) for the system is estimated at 2.63 × 10−7 cm−1 for direct absorption spectroscopy. The ultimate detection limits of CO2 and CO mixed with pure N2 at 75 Torr are 29 parts per million (ppm) and 47 ppm, respectively. It is demonstrated that the signal is highly linear with the concentration in the range of 100–800 ppm. Based on an Allan variation analysis, the minimum detectable limit of CO2 and CO is 7.5 and 14 ppm, respectively. The response time of the system is about 30 s and a relationship of temperature dependence was obtained. As an example, an in situ measurement of exhaust of alkane combustion emission is presented.

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Jackson, Carlton D., Gerald M. Cronin, and Richard J. Brown. "Subchronic Studies of Triprolidine in Fischer 344 Rats." Journal of the American College of Toxicology 12, no. 4 (August 1993): 359–67. http://dx.doi.org/10.1177/109158189301200406.

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Triprolidine, used extensively as an antihistamine, was studied for subchronic toxicity by administration as an admixture in the diet to male and female Fischer 344 rats at dosage levels of 0, 156, 312, 625, 1250, and 2500 parts per million (ppm) for 14 days and in a second study at 0, 250, 500, 1000, 2000, and 4000 ppm for 90 days. In the 14-day study, the only sign of toxicity observed either clinically or histologically was a reduction of final body weights (less than 10%) of both male and female rats in the 2500 ppm dosage group associated with reduced food consumption. In the 90-day study, final body weights were reduced, compared to controls, at the higher dosage levels with 4000 ppm resulting in a 20% and 13.4% reduction in males and females, respectively. Target organs were identified as the liver with hepatic fatty change and the parotid salivary gland, which exhibited treatment-related cytoplasmic alterations of the acinar cells. Males were more susceptible than females to both of these effects. These results indicate that rats would tolerate 2000 ppm triprolidine in a 2-year chronic bioassay without significant shortening of life span.

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Andrizal, Lifwarda, Anna Yudanur, Rivanol Chadry, and Hendrick. "A Portable Device of Air Pollution Measurement Due to Highway Exhaust Emissions Using LabVIEW Programming." JOIV : International Journal on Informatics Visualization 5, no. 4 (December 30, 2021): 422. http://dx.doi.org/10.30630/joiv.5.4.697.

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A multisensory gas device integrated with myRIO module to measure air pollution has been established. This device is programmed using the LabVIEW programming language and can measure CO2, CO, NOX, and HC pollution on roads due to motor vehicle exhaust emissions. The device and the display system are made separately using wireless network communication to make this tool portable. Exhaust Gas Analyzer (EGA) was chosen for device calibration, obtaining 3.62% on the average error after performing 30 tests. The tests for measuring CO, CO2, NOX, and HC gas levels were conducted in several locations in Padang City and performed in the morning, afternoon, and evening. The result showed that the system properly measured CO2, CO, NOX and HC pollution in parks and highways in real-time in parts per million (ppm). It also displayed varied gas measurement results in terms of time and test location with a range of CO gas values at 0.034 – 0.15 ppm, CO2 151.3 – 815.2 ppm, NOX 0.0001 – 0.004 ppm, and HC 0.04 – 0.65 ppm. In addition, the system could perform well in providing warnings by automatically activating the air indicator alert at several measurement places when the gas content on one of the gas elements and compounds at a particular location has exceeded the threshold for the clean air category. Thus, this device can be used as initial research to build a real-time air pollution measurement system using the Internet of Things (IoT).

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Jin, Ziliang, and Maitrayee Bose. "New clues to ancient water on Itokawa." Science Advances 5, no. 5 (May 2019): eaav8106. http://dx.doi.org/10.1126/sciadv.aav8106.

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We performed the first measurements of hydrogen isotopic composition and water content in nominally anhydrous minerals collected by the Hayabusa mission from the S-type asteroid Itokawa. The hydrogen isotopic composition (δD) of the measured pyroxene grains is −79 to −53‰, which is indistinguishable from that in chondritic meteorites, achondrites, and terrestrial rocks. Itokawa minerals contain water contents of 698 to 988 parts per million (ppm) weight, after correcting for water loss during parent body processes and impact events that elevated the temperature of the parent body. We infer that the Bulk Silicate Itokawa parent body originally had 160 to 510 ppm water. Asteroids like Itokawa that formed interior to the snow line could therefore have been a potential source of water (up to 0.5 Earth’s oceans) during the formation of Earth and other terrestrial planets.

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Stephens, B. B., N. L. Miles, S. J. Richardson, A. S. Watt, and K. J. Davis. "Atmospheric CO2 monitoring with single-cell NDIR-based analyzers." Atmospheric Measurement Techniques Discussions 4, no. 4 (July 8, 2011): 4325–55. http://dx.doi.org/10.5194/amtd-4-4325-2011.

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Abstract. We describe CO2 concentration measurement systems based on relatively inexpensive single-cell non-dispersive infrared CO2 sensors. The systems utilize signal averaging to obtain precision (1-σ in 100 s) of 0.1 parts per million dry air mole fraction (ppm), frequent calibrations and sample drying in order to achieve state-of-the-art compatibility, and can run autonomously for months at a time. Laboratory tests indicate compatibility among four to six systems to be ±0.1 ppm (1-σ), and field measurements of known reference-gases yield median errors of 0.01 to 0.17 ppm with 1-σ variance of ±0.1 to 0.2 ppm. From May to August 2007, a system co-located with a NOAA-ESRL dual-cell NDIR system at the WLEF tall tower in Wisconsin measured daytime-only daily averages of CO2 that differ by 0.26 ± 0.15 ppm (median ± 1 σ), and from August 2005 to April 2011 a system co-located with weekly NOAA-ESRL network flask collection at Niwot Ridge, Colorado measured coincident CO2 concentrations that differed by −0.06 ± 0.30 ppm (n = 585). Data from these systems are now supporting a wide range of analyses and this approach may be applicable in future studies where accuracy and initial cost of the sensors are priorities.

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Stephens, B. B., N. L. Miles, S. J. Richardson, A. S. Watt, and K. J. Davis. "Atmospheric CO2 monitoring with single-cell NDIR-based analyzers." Atmospheric Measurement Techniques 4, no. 12 (December 14, 2011): 2737–48. http://dx.doi.org/10.5194/amt-4-2737-2011.

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Abstract. We describe CO2 concentration measurement systems based on relatively inexpensive single-cell non-dispersive infrared CO2 sensors. The systems utilize signal averaging to obtain precision (1-σ in 100 s) of 0.1 parts per million dry air mole fraction (ppm), frequent calibrations and sample drying in order to achieve state-of-the-art compatibility, and can run autonomously for months at a time. Laboratory tests indicate compatibility among four to six systems to be ±0.1 ppm (1-σ), and field measurements of known reference-gases yield median errors of 0.01 to 0.17 ppm with 1-σ variance of ±0.1 to 0.2 ppm. From May to August 2007, a system co-located with a NOAA-ESRL dual-cell NDIR system at the WLEF tall tower in Wisconsin measured daytime-only daily averages of CO2 that differ by 0.26 ± 0.15 ppm (median ± 1 σ), and from August 2005 to April 2011 a system co-located with weekly NOAA-ESRL network flask collection at Niwot Ridge, Colorado measured coincident CO2 concentrations that differed by −0.06 ± 0.30 ppm (n = 585). Data from these systems are now supporting a wide range of analyses and this approach may be applicable in future studies where accuracy and initial cost of the sensors are priorities.

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Spector Cohen, Inna, Andrew Day, and Ron Shaoul. "Should the Glu Be Ten or Twenty? An Update on the Ongoing Debate on Gluten Safety Limits for Patients with Celiac Disease." Gastrointestinal Disorders 2, no. 3 (July 22, 2020): 202–11. http://dx.doi.org/10.3390/gidisord2030021.

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The only currently accepted and recommended treatment for individuals diagnosed with celiac disease (CD) is a strict life-long gluten-free diet (GFD). While the use of the GFD is well-established, strict adherence to diet is not easy to accomplish. In addition, the administration of a GFD may be compromised by inadvertent exposure to small amounts of gluten. International guidelines define a gluten-free product as one containing less than 20 parts per million (ppm), (20 milligrams of gluten per 1 kg of food) gluten. A number of reports have assessed the safe upper limit for gluten exposure for patients with CD, with general consensus that patients with CD should limit their daily intake to less than 50 mg.

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Pace, Christopher M., Joseph R. Donnelly, Jeffrey L. Jeter, William C. Brumley, and G. Wayne Sovocool. "Determination of Aromatic Amines in Soils." Journal of AOAC INTERNATIONAL 79, no. 3 (May 1, 1996): 777–83. http://dx.doi.org/10.1093/jaoac/79.3.777.

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Abstract A rapid liquid chromatographic (LC) method with ultraviolet (UV) or fluorescence detection was developed for parts-per-billion levels of aromatic amines in soils. 2,4-Diaminotoluene, pyridine, aniline, 2-pi-coline, 2-toluidine, 5-nitro-2-toluidine, 2-methyl-6-ethylaniline, 4-aminobiphenyl, 4-nitroaniline, 1-naphthyl-amine, 2-methoxyaniline, and 2-naphthyiamine were tested. The method involves extraction by sonication with 1% ammonium hydroxide–acetonitrile and analysis by LC using gradient elution with aqueous 0.01 M ammonium acetate–0.0005% triethylamine and acetonitrile. Recoveries of 67–106% (9.2 and 34% for 1-and 2-naphthylamines, respectively) were obtained from sand and organic-containing soils spiked in the parts-per-million range. Recoveries from sand spiked at 8.5–25 ppb were 88–105%. Recoveries from organic soil varied from nondetectable to 86% at spikes of 85–500 ppb. Detection limits ranged from 0.5 ppb for highly fluorescent 2-naphthyiamine (by fluorescence detection) to 0.5 ppm for nonfluorescing pyridines (by UV detection).

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Iqbal, Muhammad Ilyas, Muchtaruddin Mansyur, Pudji Sari, Dwi Anita Suryandari, and Pramudianto. "The Effect of Exposure Process of Toluene To The Spermatogonia Cell a Rattus Strain Wistar." Journal Of The Indonesian Medical Association 71, no. 1 (April 15, 2021): 11–17. http://dx.doi.org/10.47830/jinma-vol.71.1-2021-349.

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Intoduction: Acute and chronic exposure to toluene at high doses is known to affect all organs of the body including the spermatogenesis process. In the industrial sector, the use of toluene as a solvent is still widely used, up to 10 million tons per year. The control over health problems that may occur is carried out by applying work exposure threshold values. This research aims to explore the effect of toluene exposure at the threshold value range on spermatogenesis.Method: This research used laboratory experiment on 30 male Wistar rats which were divided into five groups of different exposure levels, namely 12.5 parts per million (ppm], 25 ppm, 50 ppm, 100 ppm, and no exposure (control). Exposure was given for 4 hours daily over 14 days through a hood with measured release in the glass cage. The toluene exposure markers observed were Malondialdehyde (MDA) in the blood tissue and testicles using the Thiobarbituric Acid Reactive Substances (TBARS) method. The effect on the spermatogenicity process was assessed by counting the spermatogonia A cells of male Wistar rats with Periodic Acid Schiff (PAS) staining and is calculated by the Abercrombie formula. Analysis of the correlation between the level of exposure and its effect on the increase in malondialdehyde, and spermatogenesis was carried out using the Spearman correlation analysis.Result: There was a moderately positive correlation between levels of toluene exposure and plasma MDA levels (r = 0.42; p = 0.025). Meanwhile, on [the issue of] the quantity of spermatogonia cells, a high level of negative correlation with exposure levels was obtained (r = -0.68; p = 0.001).Conclusion: Toluene exposure in male Wistar rats within the range of threshold values influenced the increase in plasma MDA levels and decreased the Spermatogenia A cells. However, toluene exposure did not affect the testicular MDA levels of male Wistar rats.

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Takahashi, Akira. "Measurement of Long-Term Dimensional Stability of Glass Ceramics Using a High-Precision Line Scale Calibration System." International Journal of Automation Technology 5, no. 2 (March 5, 2011): 120–25. http://dx.doi.org/10.20965/ijat.2011.p0120.

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Length measurement was conducted for two years on glass ceramics, Zerodur®and Clearceram®, which have a low coefficient of thermal expansion, and on synthetic quartz. Commercially available glass ceramics were used for evaluating long-term stability, or secular change. Synthetic quartz ensured longterm length measurement stability. Two line scales of 300 mm length made of each material for a total of six line scales were simultaneously manufactured and measured to evaluate dimensional stability variation of the materials over time. Measurements were conducted with a line scale calibration systemdeveloped by Nikon. The calibration system is a onedimensional laser interferometer, featuring reduced Abbe’s errors, laser interferometer paths in a vacuum and real-time wavelength calibration of laser frequency using a 633 nm iodine-stabilized He-Ne laser. Long-term quartz stability was 4.3 nm and 5.4 nm (2σ). The yearly stability coefficients of the two glassceramic scales were -0.22 and -0.23 parts per million per year (ppm/yr) for Zerodur and -0.16 and -0.16 ppm/yr for Clearceram. No significant difference in stability between the two scales was observed for Zerodur or Clearceram.

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Pei, Binbin, Ke Sun, Heng Yang, Chaozhan Ye, Peng Zhong, Tingting Yu, and Xinxin Li. "Oven-Controlled MEMS Oscillator with Integrated Micro-Evaporation Trimming." Sensors 20, no. 8 (April 22, 2020): 2373. http://dx.doi.org/10.3390/s20082373.

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This study reports an oven-controlled microelectromechanical systems oscillator with integrated micro-evaporation trimming that achieves frequency stability over the industrial temperature range and permanent frequency trimming after vacuum packaging. The length-extensional-mode resonator is micro-oven controlled and doped degenerately with phosphorous to achieve a frequency instability of ±2.6 parts per million (ppm) in a temperature range of −40 to 85 °C. The micro-evaporators are bonded to the resonator, integrated face-to-face, and encapsulated in vacuum. During trimming, the micro-evaporators are heated electrically, and the aluminum layers on their surfaces are evaporated and deposited on the surface of the resonator that trims the resonant frequency of the resonator permanently. The impact of the frequency trimming on the temperature stability is very small. The temperature drift increases from ±2.6 ppm within the industrial temperature range before trimming to ±3.3 ppm after a permanent trimming of −426 ppm based on the local evaporation of Al. The trimming rate can be controlled by electric power. A resonator is coarse-trimmed by approximately −807 ppm with an evaporation power of 960 mW for 0.5 h, and fine-trimmed by approximately −815 ppm with an evaporation power of 456 mW for 1 h. Though the Q-factor decreases after trimming, a Q-factor of 304,240 is achieved after the trimming of −1442 ppm.

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Nielsen, David G., and Richard S. Cowles. "Preventing White Grub Infestation in Container-Grown Nursery Stock." Journal of Environmental Horticulture 16, no. 4 (December 1, 1998): 202–7. http://dx.doi.org/10.24266/0738-2898-16.4.202.

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Abstract Preplant media incorporation of Talstar 0.2 G (bifenthrin) at 10 ppm (parts per million) or Fireban 1.5 G (tefluthrin) at 15 ppm, based on dry weight of the medium, provided complete control of Japanese beetle (Popillia japonica Newman), oriental beetle [Exomala orientalis (Waterhouse)], and European chafer [Rhizotrogus majalis (Razoumowsky)] in container nursery plants for two growing seasons. Talstar 0.67 F drenched immediately after planting also prevented establishment of these species in containers for two growing seasons. Marathon 1 G (imidacloprid) preplant media incorporated at 6–17.8 g (a.i.)/m3, provided incomplete control, while Marathon 60 W was completely effective when drenched in mid-summer prior to inoculating the pots with eggs. Other granular products mixed into potting media, including 10 ppm of fipronil or Mach 2, or 150 g (a.i.)/m3 of Lorsban or SuSCon Green, provided good control for one season. Several treatments prevented establishment of Japanese but not oriental beetle grubs. Curative drenches were generally ineffective. Registered treatments providing two years of control (Talstar at 10–25 ppm) can be used by growers to prevent white grub larval establishment in containers. Their usage should allow shipment of treated plants throughout the United States and Canada.

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Cadnum, Jennifer, Heba Alhmidi, and Curtis Donskey. "Planes, Trains, and Automobiles: Use of Carbon Dioxide Monitoring to Assess Ventilation During Travel." Pathogens and Immunity 7, no. 1 (February 25, 2022): 31–40. http://dx.doi.org/10.20411/pai.v7i1.495.

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Background: Travel poses a risk for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory viruses. Poorly ventilated indoor settings pose a particularly high risk for transmission. Methods: We used carbon dioxide measurements to assess adequacy of ventilation during 5 trips that included air travel. During selected parts of each trip that involved indoor settings, we monitored carbon dioxide levels every 1 minute and recorded peak levels and the number of people present. Carbon dioxide readings above 800 parts per million (ppm) were considered an indicator of suboptimal ventilation. Results: Carbon dioxide levels remained below 800 ppm during train rides to and from the airport and inside airports except in a crowded boarding area with ~300 people present. Carbon dioxide levels exceeded 800 ppm inside the airplanes, but the air was filtered with high efficiency particulate air filters. Carbon dioxide levels remained below 800 ppm in common areas of a hotel but exceeded 800 ppm in a hotel room with 2 to 3 occupants and in a fitness center with 3 people exercising. In restaurants, carbon dioxide levels increased above 800 ppm during crowded conditions with 24 or more people present and 75% or more seat occupancy. Conclusion: Our results suggest that ventilation may be sufficient to minimize the risk for airborne transmission in many situations during travel. However, ventilation may be suboptimal in some areas or under certain conditions such as in hotel rooms or when restaurants, fitness centers, or airplane boarding areas are crowded. There is a need for larger scale studies to assess the quality of ventilation in a wide range of community settings.

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Journal articles on the topic 'Parts per million (ppm)'

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