Glass Flasks Research Articles

Assessing infrared intensity using the evaporation rate of liquid hydrogen inside a cryogenic integrating sphere for laser fusion targets.

Infrared (IR) heating processes have been studied to form a deuterium layer in an inertial confinement fusion target. To understand the relationship between the IR intensity and the fuel layering time constant, we have developed a new method to assess the IR intensity during irradiation. In our method, a glass flask acting as a dummy target is filled with liquid hydrogen (LH2) and is then irradiated with 2-μm light. The IR intensity is subsequently calculated from the time constant of the LH2 evaporation rate. Although LH2 evaporation is also caused by the heat inflow from the surroundings and by the background heat, the evaporation rate due to IR heating can be accurately determined by acquiring the time constant with and without irradiation. The experimentally measured IR intensity is 0.66 mW/cm2, which agrees well with a value estimated by considering the IR photon energy balance. Our results suggest that the present method can be used to measure the IR intensity inside a cryogenic system during IR irradiation of laser fusion targets.

Storage stability studies and field application of low cost glass flasks for analyses of thirteen ambient VOCs using proton transfer reaction mass spectrometry

Ambient volatile organic compounds play a key role in atmospheric chemistry and air pollution studies due to their chemical reactivity and in several instances high toxicity. Quantification of ambient whole air samples which contain reactive and short-lived VOCs such as acetaldehyde, isoprene, dimethylsulphide and trimethylbenzenes at ppt-ppb concentrations is analytically challenging and generally accomplished using online proton transfer reaction mass spectrometry. Deployment of online instrumentation is still not feasible in several regions of the world due to practical constraints (power, safety issues). Consequently there is paucity of VOC data in vast regions of the world. We present here, the validation and application of a novel method for ambient VOC speciation and emission factor studies using low cost (<100 USD) whole air glass flask samplers and offline proton transfer reaction mass spectrometry that can help reduce the paucity of VOC datasets. Experiments to assess the stability during storage of thirteen VOCs, many of which are very reactive, showed that acetaldehyde, acetonitrile, acetone, dimethylsulphide, methyl vinyl and methyl ethyl ketones, benzene, xylenes, trimethylbenzenes and monoterpenes can be quantified reproducibly within the respective precision error (e.g. 40% at 100ppt α-pinene and 3% at 13ppb acetaldehyde) between collection and storage (at >95% confidence), for samples analyzed within 10days of collection. For toluene and isoprene, similar results were obtained until day 9 and 1, respectively and at confidence >70%, over the 10day period. A storage artefact was observed for methanol resulting in higher analytical uncertainty of upto 40%. We applied the method for measuring toluene/benzene emission ratios and aromatic VOCs in traffic plumes, and determining VOC emission factors (gVOC/kg fuel) from an agricultural wheat straw fire in India. The results of this study demonstrate that use of the low cost glass flask samplers described herein can significantly improve acquisition of spatially and temporally resolved datasets for atmospheric chemistry and air quality studies at sites where online deployment of instruments remains unfeasible.

Graphene Suspended on Silicon Nanowire Arrays for Enhanced Gas Sensing

Graphene is attractive for gas sensing due to its large surface area to volume ratio. Gas molecules adsorbed on the surface of graphene change its electrical conductivity, which can be measured as a resistance change as a function of time. Normally, only one side of the graphene is exposed to the gas [1]. Exposing both sides for molecule adsorption should increase its sensitivity as the effective surface area is increased. Graphene can be suspended on mesas of a patterned substrate [2]. The maximum distance across which graphene can be suspended without substantial deformation is 100 μm [2]. Contacts need to be defined aligned to the mesa structures to avoid breaking the graphene layer. We suspend graphene over a large area (~cm2), namely on top of a of silicon nanowire array (SiNWA) [3]. This approach removes the need for aligned contacts. In addition we found that it increases the sensitivity to gas molecules dramatically. We present results of the conductivity variation of suspended graphene on Si NWAs in response to NH3 molecules evaporating from 1 ml of aqueous NH4OH in a glass flask [4] in a closed container. The SiNWA was fabricated using metal assisted chemical etching (MACE) [5]. A p-type Si substrate, with resistivity ρ = 1-5 Ω cm, was processed in three consecutive steps. First was the nucleation of Ag nanoparticles (NPs) on the surface using 0.06M AgNO3:28.2M HF:H2O for 10 min. Subsequently, the NWs were etched in 0.6M H2O2:28.2M HF:H2O for 10 min. Finally, the Ag NPs were removed in 67% HNO3:H2O. CVD grown, multilayer graphene on Ni was transferred to the SiNWA via a PMMA support layer. To ensure good adhesion between graphene and SiNWA, the PMMA was dissolved in vapour rather than liquid acetone [3]. The SEM images (see Figure) show that graphene is suspended on the SiNWA over a large area. The resistivity of the graphene measured with a four-point-probe (4PP) set-up was ρ = 10-3 Ωcm. The SiNWA support was found to be non-conductive in the direction parallel to the substrate. To compare the influence of the increase in effective surface area, NH3 adsorption measurements were carried using both graphene-on-SiNWA (GrNW) and graphene-on-SiO2 (GrOx). In the figure, the resistivity is plotted as a function of time while NH3 was evaporating from NH4OH. All measurements were carried out at room temperature. Graphene behaves as a p-type semiconductor, due to ambient H2O and O2 influencing electron and hole mobilities [6]. Since, NH3 molecules are electron donors [7], the conductivity decreases when NH3 molecules adsorb onto graphene. When the current saturates, the NH4OH was removed and the lid of the container was opened. The reaction time of GrNW to NH3 is 5 times larger than for GrOx. There is a 30% increase in resistivity for GrNW compared to only 6% for GrOx, showing a clear increase in sensitivity of the suspended graphene layer. Both samples recover slowly to the initial resistivity value when NH4OH is removed. GrNW needs more time to saturate and recover, probably due to NH3 molecules entrapment in the SiNWA. Results from further experiments with different NWA densities will also be presented at the conference to analyse this phenomenon.

A different kind of chemical plant.

Photochemistry Leaves are beautifully compact photochemical reactors, especially in comparison with the glass flask and lamp combinations prevalent in chemistry laboratories. Cambie et al. now report an artificial leaf that takes the architecture of the natural version closely to heart.

Flask sealing on in vitro seed germination and morphogenesis of two types of ornamental pepper explants

ABSTRACT: The influence of flask sealing and explant source on the in vitro morphogenesis of pepper, were evaluated in Capsicum annuum. Seeds were sterilized and inoculated in Murashige and Skoog media supplemented with vitamins, myo-inositol, sucrose, and agar. Gas exchange was evaluated in the germination stage by comparing 3 flask-sealing systems: rigid polypropylene lids (PLs) without vents, PLs with 1 vent, and PLs with 2 vents covered with membranes. In the regeneration stage, cotyledon and hypocotyl segments were transferred to the organogenesis-inducing media, being the different sealing types also tested in a factorial scheme. Photosynthetic pigments, morphological and hystological analyses were conducted for each treatment. Plants maintained in glass flasks capped with vented lids showed more vigorous growth and differentiated anatomical structures. These treatments resulted in taller plants, higher numbers and more expanded leaves, higher fresh and dry weights, and an increase in photosynthetic pigments. Cultivation of C. annuum in flasks with reduced gas exchange was more effective on callus induction. During the regeneration stage, hypocotyls were more effective than cotyledons. Sealing type influenced the morphogenic responses of pepper, demonstrating that an increase in gas exchange has a positive effect on biomass production and acclimatization of the plantlets.

Anciennes recherches, nouvelles considérations sur la crypte repérée dans le périmètre de la rue Karl Marx à Constanța

La începutul anilor 1980, în cursul unor lucrări de sistematizare urbană desfășurate în perimetrul fostei străzi K. Marx (astăzi strada Revoluției din 22 Decembrie 1989), au fost identificate vestigiile unui edificiu de cult creștin. Intervenția antropică brutală, realizată cu mijloace mecanice, a condus la distrugerea cvasi-totală a zidurilor perimetrale de sud și de vest ale monumentului creștin, a pavimentului său realizat din cărămidă, dar și la afectarea parțială a criptei pentru relicve aflate sub nivelul sanctuarului. Cu toate acestea, planul și detaliile constructive privind cripta au putut fi reconstituite cu destulă acuratețe. Pe baza datelor disponibile (reunite în contribuția lui Rădulescu, Lungu din 1989, precum și a clișeelor păstrate în arhiva fotografică a MINA Constanța), autorii își propun să redeschidă dosarul arheologic al acestei descoperiri, rediscutând contextul arheologic, precum și flaconul-relicvar din sticlă descoperit intact în absidiola estică a criptei. Vor fi, de asemenea, avute în vedere detalii privind tehnica de construcție a criptei, decorația murală, cu privire specială asupra flaconului lenticular din sticlă, sigilat practic în absidiola estică a dispozitivului pentru conservarea moaștelor. Acest obiect, unic în peisajul religios de la Tomis, oferă informații suplimentare despre modul de venerare, accesibilitatea și contextul depunerii relicvelor în Scythia și oferă noi chei de lectură a acestor resturi sfinte în monumentele creștine din capitala religioasă a provinciei.

Identifikasi Kandungan Ekstrak Kayu Jati Menggunakan Py-GCMS

Teak wood (Tectona grandis Lf.) in the form of sawdust a byproduct/waste from the furniture industry has a considerable amount and has not been utilized optimally. This study aims to determine the content of extractive teak wood (Tectona grandis Lf.). The method used is the hot water solubility. Muna's teak wood powder weighing 4,076 g soaked in distilled water as much as 100 ml glass flask, then heated in a water bath at a temperature of 100 oC for 3 hours. The content of extractive dissolved in a liquid further characterized using Py-GCMS. Results of the analysis of Py-GCMS to extract teak wood showed concentrations of some substances, such as Carbamic acid (70,70%), mono ammonium salt (CAS) Ammonium carbamate (70,70%), Acetic acid (CAS) Ethylic acid (10,52%), Acetic acid (CAS) Ethylic acid (2,35%), Acetic acid (CAS) Ethylic acid (3,26%), and Phenol (CAS) Izal (13,17%)

Oxygen solubility measured in aqueous or oily media by a method using a non-invasive sensor

The amount of dissolved oxygen (O2) in oils is one of the major factors that affect the extent of oil oxidation reactions. The aim of this work was to develop an experimental method to determine the Henry's law constant in oils, using a portable optical device for easy and non-intrusive O2 partial pressure measurement. The principle is based on the effect of quenching of luminescence by oxygen using a sensor probe glued inside a transparent glass flask. The method uses a mass conservation equation written for oxygen in both liquid and gaseous phases inside a closed flask. It was validated on water in the range of 5–50 °C, and then applied to non-polar media (dodecane, vegetable oil and Miglyol). The results show that oxygen is 5 times more soluble in sunflower oil than in water. This method is easy-to-implement and makes it possible to measure the Henry's constant for O2 in various types of vegetable oils.

Microbial community composition in Brazilian stored diesel fuel of varying sulfur content, using high-throughput sequencing

The reduction of sulfur content in diesel is a worldwide trend that seeks to minimize the environmental impact arising from the combustion of this fuel in large cities. However, there is no reliable information on the effect of such a reduction on the formation of mainly aerobic microbial biomass in vehicle and storage tanks. The objective of this study was to assess the microbial community structure using next generation sequencing technique, and to evaluate the microbial biomass in pure diesel containing various sulfur concentrations. Storage conditions were simulated in glass flasks containing mineral medium and pure diesel, with varying sulfur content: UHSD (⩽1800ppm sulfur); HSD (⩽500ppm sulfur); LSD (⩽50ppm sulfur) and ULSD (⩽10ppm sulfur). Were assessed two microbial contamination levels in the diesel: low contamination (∼103CFUL−1) and medium contamination (∼105 bacterial cells and fungal spores mL−1). The flasks were incubated at 30°C and monitored every 10days over 40days. Microbial biomass formation was observed in all microcosms, but the highest biomass level at all times was in UHSD with medium contamination (p<0.05). Results from biomass production and proton nuclear magnetic resonance showed that the ULSD, was not prone to microbial contamination probably because has highly branched carbon chain. Overall, 36 different phyla were identified by sequencing of 16S rDNA and four by 18S rDNA, with Firmicutes (∼49%), Bacteroidetes (∼25%), Actinobacteria (∼17%) and Ascomycota (>99%) being the most abundant. Results suggested that bacterial diversity is increased when low sulfur concentrations are present. Our results reveal a complex microbial diversity from 16S rDNA and confirm the existence of the major fungal Phyla (Ascomycota, Basidiomycota, Chytridiomycota and Glomeromycota) with a large fraction of microorganisms as yet undescribed, reinforcing the importance of understanding the fuel environment in establishing control methods of microbial growth in storage tanks and in bioremediation programs for environments contaminated by fuel.

Technological stability of solid lipid nanoparticles loaded with phenolic compounds: Drying process and stability along storage

Solid lipid nanoparticles (SLNs) have been widely studied and tested as vehicles for natural compounds. Recently, Witepsol and Carnauba SLNs were shown to be effective systems for the entrapment of rosmarinic acid (RA) and herbal extracts. In the present work, the improvement of stability and bioactivity of these systems was studied. Thus, the freeze-drying of SLNs produced with Witepsol and Carnauba waxes loaded with RA and herbal extracts (sage and savory) were tested. The use of three different cryoprotectants (glucose, mannitol and trehalose) at two different concentrations (5 and 10%, w/v) were evaluated. Furthermore, the prepared SLNs were stored under different conditions (atmosphere, temperature, absence or presence of light) and in different packaging materials, over 365 days. The effect on the SLNs physical stability and bioactivity was assessed. The most suitable cryoprotectant was mannitol at 10% (w/v) for all formulations tested. The solid state of SLNs, with storage at room temperature, in glass flasks, protected from light and under N2 controlled atmosphere were the best storage conditions in which the SLNs bioactivity was maintained during 365 days.

A proposal for a test method for assessment of hazard property HP 12 (“Release of an acute toxic gas”) in hazardous waste classification – Experience from 49 waste

A stepwise method for assessment of the HP 12 is proposed and tested with 49 waste samples. The hazard property HP 12 is defined as “Release of an acute toxic gas”: waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid. When a waste contains a substance assigned to one of the following supplemental hazards EUH029, EUH031 and EUH032, it shall be classified as hazardous by HP 12 according to test methods or guidelines (EC, 2014a, 2014b). When the substances with the cited hazard statement codes react with water or an acid, they can release HCl, Cl2, HF, HCN, PH3, H2S, SO2 (and two other gases very unlikely to be emitted, hydrazoic acid HN3 and selenium oxide SeO2 – a solid with low vapor pressure). Hence, a method is proposed:1.Measurement of the volume of gases emitted into contact with water or an acid (solid/liquid ratio of 10L water or acid/kg raw waste, acid 2.5M HNO3).2.If gas is emitted at a rate higher than 0.1L of gas/kg waste in 5min (limit of quantification of the automated calcimètre used here), checking if one of the cited gases is emitted with electrochemical detection probes or simple qualitative colorimetric methods.3.If one of these gases is detected, speciation of the emitting substance(s) (calculation by the “worst case” method from elements concentrations, or by specific analytic methods) and checking whether they have a hazard statement code EUH029, EUH031 or EUH032 (a list is provided).For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1L of gas per kg of waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric bombs or glass flasks were done and confirmed the results. Identification of the gases by portable probes showed that most of the tested samples emit mainly CO2. Toxic gases are emitted by four waste: metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator (H2S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in these trials started before the present definition of HP 12. According to the definition of HP 12, only the H2S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed. These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are also classified as hazardous for other properties (HP 7, 10and14 for one of them, and HP 10and14 for the other one respectively). Given these results, it can be assumed that few common household and industrial waste will be classified hazardous only by HP 12.

Development and evaluation of a suite of isotope reference gases for methane in air

Abstract. Measurements from multiple laboratories have to be related to unifying and traceable reference material in order to be comparable. However, such fundamental reference materials are not available for isotope ratios in atmospheric methane, which led to misinterpretations of combined data sets in the past. We developed a method to produce a suite of synthetic CH4-in-air standard gases that can be used to unify methane isotope ratio measurements of laboratories in the atmospheric monitoring community. Therefore, we calibrated a suite of pure methane gases of different methanogenic origin against international referencing materials that define the VSMOW (Vienna Standard Mean Ocean Water) and VPDB (Vienna Pee Dee Belemnite) isotope scales. The isotope ratios of our pure methane gases range between −320 and +40 ‰ for δ2H–CH4 and between −70 and −40 ‰ for δ13C–CH4, enveloping the isotope ratios of tropospheric methane (about −85 and −47 ‰ for δ2H–CH4 and δ13C–CH4 respectively). Estimated uncertainties, including the full traceability chain, are &lt; 1.5 ‰ and &lt; 0.2 ‰ for δ2H and δ13C calibrations respectively. Aliquots of the calibrated pure methane gases have been diluted with methane-free air to atmospheric methane levels and filled into 5 L glass flasks. The synthetic CH4-in-air standards comprise atmospheric oxygen/nitrogen ratios as well as argon, krypton and nitrous oxide mole fractions to prevent gas-specific measurement artefacts. The resulting synthetic CH4-in-air standards are referred to as JRAS-M16 (Jena Reference Air Set – Methane 2016) and will be available to the atmospheric monitoring community. JRAS-M16 may be used as unifying isotope scale anchor for isotope ratio measurements in atmospheric methane, so that data sets can be merged into a consistent global data frame.

Root canal disinfection comparing conventional irrigation vs photon-induced photoacoustic streaming (PIPS) using a buffered 0.5 % sodium hypochlorite solution

Abstract Background The purpose of this study was to assess the antimicrobial effect of a buffered 0.5 % sodium hypochlorite solution activated by photon-induced photoacoustic streaming compared to conventional irrigation. Methods The canals on 48 single canal lower bicuspids were cleaned and shaped using rotary instrumentation. All roots were autoclaved for 20 min. Thirty-six of the roots were placed in glass flasks with blood heart infusion media and Enterococcus faecalis (ATCC 4082) for 4 weeks. The remaining 12 roots were placed in a sterile environment and served as negative controls. The contaminated roots were irrigated by conventional means using a buffered 0.5 % sodium hypochlorite solution with or without photon-induced photoacoustic streaming (PIPS) activation (n = 12 each group). The remaining 12 roots did not receive any treatment and served as positive controls. The apical 3 mm of each tooth was sectioned and pulverized. The pulverized samples were collected and placed in Eppendorf micro-centrifuge tubes with sterile phosphate-buffered saline. Thirty MicroLiters of the collected samples was then placed in the blood heart infusion media and incubated for 24 h at 37 °C. Colony forming units (CFU) were compared with Wilcoxon signed ranked test. Mann-Whitney U test was used to assess PIPS effectiveness in comparison with conventional irrigation. Results Both regimens reduced significantly the number of CFU; however, reduction was significantly higher for the PIPS group (p = 0.002). Conclusion Buffered 0.5 % sodium hypochlorite delivered by conventional method was effective in removing E. faecalis from contaminated root canals; however, activation of a buffered 0.5 % sodium hypochlorite solution by PIPS significantly increased its antimicrobial capacity.

Solar dish concentrator for desalting water

The purpose of this study was to build, characterize and analyze the performance of a solar dish concentrator for desalinating water. To build this device, an equatorial mount was adapted to track the sun, a satellite dish was mirrored and the distillation system was assembled using a glass flask, a copper tube and a silicone tube. The system was characterized experimentally based on the main parameters that define a solar concentrator. However, to determine the potential energy of the device, dynamic heating was simulated by computer and validated experimentally. Finally, to analyze the performance of the solar dish concentrator in terms of water desalination, experiments were conducted with semi-continuous insertion of saline solution containing concentrations of 0–4% of sea salt. The yield of distilled water varied of 4.95kg/m2day (0%) to 4.11kg/m2day (4%), a consequence of colligative effects. Therefore, a solar dish concentrator was built with a simplified distillation system whose yield per square meter provided sufficient drinking water to meet the daily needs of at least two adults.

Technology of nondestructive light gas extraction from ice tested on samples from a bore hole above Vostok Lake

Nondestructive technology has been developed for the extraction of light gases dissolved in ice. The technology has been tested on samples of atmospheric and congealed ice of the 5-G3 bore hole of the Vostok station (East Antarctica) extracted from depths of 3457–3698 m. Down to 3539 m, ice is of an atmospheric origin, while ice deposited deeper is formed by natural water of Vostok Lake frozen on the glacier. Light gases were extracted into samplers (glass flasks) in the course of the 3-day degassing of samples freshly elevated from a bore hole. The samples were analyzed on the FT-1 time-of-flight mass spectrometer 6 months after sampling. Measurements reveal the presence of amounts of helium as well as molecular hydrogen considerably exceeding the atmospheric values. Measured values of gas ratio H2/4He = 5.4 ± 1.9 in the samples from depths of 3596–3698 m exceed the atmospheric values by more than an order of magnitude.

Estrategias para disminuir la necrosis apical en la multiplicación y el enraizamiento in vitro del Pistacho

El pistacho (Pistacia sp.) es uno de los frutales menos explotados, entre las principales causas está el elevado costo del material vegetal por las dificultades de propagación de la especie. La propagación in vitro ofrece un gran potencial para la industria de esta especie por la multiplicación a gran escala de clones seleccionados. El objetivo del presente trabajo fue controlar la necrosis apical de los brotes en la propagación in vitro del pistacho. A partir de brotes jóvenes de plantas de esta especie mantenidas en casas de cultivo, se procedió a su desinfección con hipoclorito de sodio al 1% durante diferentes tiempos. Las yemas apicales y axilares se establecieron en el medio de cultivo Murashige &amp; Skoog (1962) modificado y enriquecido con 1 mg/L de Metatopolina. Se evaluaron diferentes tipos de frascos, número y tipo de explantes y formulaciones de medios de cultivo durante dos subcultivos de multiplicación y en el enraizamiento. El frasco de cristal de 200 ml de capacidad, la línea prolifera y el medio de cultivo DKW lograron los valores más bajo de necrosis apical. En la fase de multiplicación se presentaron valores bajo en todos los tratamientos ensayados sin diferencia estadísticas entre ellos en comparación con el enraizamiento donde la necrosis apical alcanzó valores superiores. El medio DKW y las líneas prolíferas lograron los menores valores. El medio de cultivo MS modificado, favoreció el número de segmentos enraizados y el DKW (Driver &amp; Kuniyuki, 1984) el número de segmentos que brotaron, presentando este último menor incidencia de necrosis apical.Palabras clave: forestales, medios de cultivo, nueces, propagación in vitro.

Automated simultaneous measurement of the δ(13) C and δ(2) H values of methane and the δ(13) C and δ(18) O values of carbon dioxide in flask air samples using a new multi cryo-trap/gas chromatography/isotope ratio mass spectrometry system.

The isotopic composition of greenhouse gases helps to constrain global budgets and to study sink and source processes. We present a new system for high-precision stable isotope measurements of carbon, hydrogen and oxygen in atmospheric methane and carbon dioxide. The design is intended for analyzing flask air samples from existing sampling programs without the need for extra sample air for methane analysis. CO2 and CH4 isotopes are measured simultaneously using two isotope ratio mass spectrometers, one for the analysis of δ(13) C and δ(18) O values and the second one for δ(2) H values. The inlet carousel delivers air from 16 sample positions (glass flasks 1-5 L and high-pressure cylinders). Three 10-port valves take aliquots from the sample stream. CH4 from 100-mL air aliquots is preconcentrated in 0.8-mL sample loops using a new cryo-trap system. A precisely calibrated working reference air is used in parallel with the sample according to the Principle of Identical Treatment. It takes about 36 hours for a fully calibrated analysis of a complete carousel including extractions of four working reference and one quality control reference air. Long-term precision values, as obtained from the quality control reference gas since 2012, account for 0.04 ‰ (δ(13) C values of CO2 ), 0.07 ‰ (δ(18) O values of CO2 ), 0.11 ‰ (δ(13) C values of CH4 ) and 1.0 ‰ (δ(2) H values of CH4 ). Within a single day, the system exhibits a typical methane δ(13) C standard deviation (1σ) of 0.06 ‰ for 10 repeated measurements. The system has been in routine operation at the MPI-BGC since 2012. Consistency of the data and compatibility with results from other laboratories at a high precision level are of utmost importance. A high sample throughput and reliability of operation are important achievements of the presented system to cope with the large number of air samples to be analyzed. Copyright © 2016 John Wiley & Sons, Ltd.

Construction and Demonstration of a Standardized Hop Boiled Water Extraction Method and its Application for a Sensory Evaluation System of Hop Aroma Characteristics

Hops impart characteristic flavors to beer. The key hop aroma compounds contributing to beer flavor have been intensively identified and studied; however, sensory evaluation remains necessary to evaluate hop aromas. High-throughput evaluation is vital, especially for preliminary hop seedling selection in breeding programs. Most of the volatile essential oils in hops are significantly evaporated during the wort boiling process after hop dosing. Furthermore, the compositions of essential oils in the boiled wort are changed from the original compositions in the hops as a result of the chemical and physical properties of the volatile aroma components, such as hydrophobicity and volatility. The so-called hop tea method is conducted to facilitate hop development but has not yet been scientifically discussed. In this study, we propose a sensory evaluation system of hop aromas based on the standardized hop boiled water (HBW) extraction method, in which hops are dosed to an α-acid level of 0.5 g/L in distilled water in glass flasks and autoclaved. Descriptive sensory evaluation was applied for the HBW samples, and nine descriptors were established for HBW evaluation. The results indicated that HBW extraction provided a good simulation of late-hopping in the wort boiling process. The aroma characteristics of hop varieties, even those harvested in different crop years, could be characterized by the sensory evaluation system. Moreover, the flavor hops were discriminated from the other categories of hop varieties (aroma hops and bitter hops). Consequently, the HBW method and sensory evaluation system proposed in this report allow for a high-throughput evaluation of hop cone samples suitable for the selection of new flavor hops.

Evaluation of eleven Mexican cultivars of prickly pear cactus trees for possibly utilization as animal fed: in vitro gas production

In production systems of prickly pear fruit and prickly pear cactus, significant amounts of pruned material, which could be used as an ingredient in animal feeding, is generated. The aim of this study was to measure the nutrient content, fermentation kinetics and in vitro digestibility of eleven cultivars of cladodes of prickly pear cactus. The fermentation was measured indirectly using the gas production technique, where 500 mg of DM substrate (prickly pear cactus cultivars) were placed in amber glass flasks of 125 mL with 90 mL of ruminal inoculum under a continuous flow of CO2. Flasks were hermetically wrapped up with a rubber stopper and a metal ring, and were placed in a water bath at 39 °C. The fermentation gas pressure was measured using a monometer at 0, 2, 4, 6, 8, 12, 16, 20, 24, 32, 38, 50 and 72 h incubation. Results show that the chemical composition ranged between (g kg−1 DM): 64 and 160 g kg−1 dry matter (DM), 137–293 g kg−1 DM ash, 52–101 g kg−1 DM crude protein, 3–22 g kg−1 DM ether extract, 251–393 neutral detergent fiber and 132–192 acid detergent fiber. The gas volume was different (p < 0.05) among cultivars, with the Red Vigor cultivar having the largest volume at 378 mL g−1 DM. The highest volume of gas was produced during the first 24 h in on average 67 % of the total produced. The in vitro DM digestibility displayed values of up to 82 % in the Roja Pelota cultivar. It can be concluded that the cladodes of prickly pear cactus from different cultivars can be used in animal feed for its good rumen fermentation characteristics.

Gilding on glass: New evidence from a 17th century flask found in Portugal

In the present work, a set of archaeological glass fragments belonging to a singular 17th century glass flask with gilded decoration was sampled and analyzed. The fragments were excavated in Coimbra, Portugal. The main focus of this study is to bring to light the flask production technique, in particular the gilding process, and additionally, to investigate the object's provenance based on the composition of the glass. A comprehensive survey of ancient and traditional glass gilding techniques is also presented.The glass and the gilded areas were characterized using micro energy dispersive X-ray fluorescence spectroscopy (μ-EDXRF), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray electron probe micro-analysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).The flask is made of soda-lime-silica glass and the use of coastal plant ashes is suggested by the relatively high content of MgO and K2O, as well as by the presence of chlorine. The high alumina content excludes a Venetian provenance, and with regard to the contents of Na2O, SiO2, K2O, and CaO, the glass composition is distinct from the façon-de-Venise glasses which have been studied, and only comparable to a few 17th century millefiori glasses, also recovered in Coimbra.Lead was detected in the gilded areas suggesting that a lead based mordant was used in the gilding process to promote the adhesion of the gold leaf to the glass during the low temperature reheating of the object. The gold leaf composition was determined by LA-ICP-MS, and it was possible to ascertain its purity: between 22 and 23 gold carats.