32 resultados para Glassware.


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List of prices (2 pages, handwritten) for items such as furniture, curtains, pictures, carpets and glassware. This is embossed with the Welland Canal stamp, Dec. 1855.

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The efficiency of different methods for the decontamination of glassware used for the analysis of dissolved organic carbon (DOC) was tested using reported procedures as well as new ones proposed in this work. A Fenton solution bath (1.0 mmol L-1 Fe2+ and 100 mmol L-1 H2O2) for 1 h or for 30 min employing UV irradiation showed to combine simplicity, low cost and high efficiency. Using the optimized cleaning procedure, the DOC for stored UV-irradiated ultrapure water reached concentrations below the limit of detection (0.19 mu mol C L-1). Filtered (0.7 mu m) rain samples maintained the DOC integrity for at least 7 days when stored at 4 degrees C. The volatile organic carbon (VOC) fraction in the rain samples collected at two sites in São Paulo state (Brazil) ranged from 0% to 56% of their total DOC content. Although these high-VOC concentrations may be derived from the large use of ethanol fuel in Brazil, our results showed that when using the high-temperature catalytic oxidation technique, it is essential to measure DOC rather than non-purgeble organic carbon to estimate organic carbon, since rainwater composition can be quite variable, both geographically and temporally. (C) 2007 Elsevier Ltd. All rights reserved.

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This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench. [Authors]

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A simple laboratory technique is described for the synthesis of cyclopentadienylthallium and methylcyclopentadienylthallium and their use in the preparation of air sensitive metallocenes in solution. It does not use manifold, drybox or any other special glassware and was applied to the synthesis of cobaltocene, nickelocene and their methyl substituted analogs.

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A new approach for teaching in basic experimental organic chemistry is presented. Experimental work goes on parallel to theoretical lectures leading to an immediate application of theoretical concepts transmitted therein. One day/week is dedicated exclusively to the organic laboratory. Reactions are proposed as problems to be solved; the student has to deduce the structure of the product on the basis of his observations, the analytical data and his mechanistical knowledge. 70 different experiments, divided in 7 thematical chapters, are presented. All experiments require the analysis and discussion of 1H and 13C NMR, IR and UV spectra. Additional questions about each reaction have to be answered by the student in his written report. Laboratory safety is garanteed by the exclusion or substitution of hazardous and toxic reagents. Microscale preparations are adopted in most cases to lower the cost of materials and the amount of waste. Recycling of many reaction products as starting materials in other experiments reduces the need for commercial reagents and allows the execution of longer reaction sequences. Only unexpensive standard laboratory equipment and simple glassware are required. All experiments include instructions for the save treatment or disposal of chemical waste.

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The contextualized understanding of concepts in Chemistry by students from other areas is a challenging task. In this experiment, the synthesis of biodiesel is done by base catalyzed transesterification of refined soy oil with methanol at room temperature and common glassware found in any chemistry laboratory. The proposal permits introducing several concepts, such as that of emulsion, viscosity and catalysis to illustrate an activity based on an actual problem. In this didactic approach, some common problems of biodiesel production, such as soap formation and phase separation, are introduced into the procedure in order to raise questions and motivate the students to participate in the experimental work and stimulate reflections about critical aspects of biodiesel production. This experiment was carried out in the first semester of 2006, in experimental general chemistry taken by physics and agricultural, civil and chemical engineering students of UNICAMP.

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In this paper, we present procedures for the treatment and final disposal of residual solutions containing chromium, in order to evaluate the effectiveness of chemical precipitation of the metal and the potential of the glass encapsulation technique, using broken laboratory glassware. The results demonstrated that pH-values convenient for chemical precipitation are between 10 - 11. With regard to Cr(OH)3 encapsulation, the leaching and solubilization tests allowed to classify the waste as non-dangerous and non-inert. Finally, it is pointed out that the adoption of waste management practices in universities should be encouraged, helping to train professionals skilled in good laboratory practices.

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This paper describes a five-week mini-project for a general chemistry laboratory course. Activities are included preparations of ethanol and sucrose solutions, calculation of concentrations, determination of densities with densimeters, sugarcane juice fermentation with CO2 capture in alkaline solution, distillation, and determination of amounts of ethanol and CO2 formed. Abilities and concepts normally present in practical general chemistry courses are covered: use of balances, volumetric glassware and densimeters, preparation of solutions, performing of dilutions, determination of solution densities, observation of chemical reactions, stoichiometric calculations, separation of mixtures, and titration.

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This paper describes a three-week mini-project for an Experimental Organic Chemistry course. The activities include N-C cross-coupling synthesis of N-(4-methoxyphenyl) benzamide in an adapted microwave oven by a copper catalyst (CuI). Abilities and concepts normally present in practical organic chemistry courses are covered: use of balances, volumetric glassware, separation of mixtures (liquid-liquid extraction and filtration), chromatographic techniques, melting point determination and stoichiometric calculations.

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Yttrium-aluminum oxides are interesting compounds and they have been extensively used as host for lasers and phosphors, due to their stable physical and chemical properties. The fabrication of yttrium-aluminum garnet (YAG) has been investigated thoroughly. Single-crystal YAG is expensive and to produce it a new way has been investigated. This process consists of modifying the methodology of reagents mixture and the process of heating them. The microwave irradiation is used to heat-treat the oxide mixture. The traditional synthesis of YAG powders occurs through the reaction of aluminum and yttrium powders at high temperatures. With this work we investigated the preparation of YAG by non-hydrolytic sol-gel route as an alternative methodology to obtain yttrium-aluminum matrix from inorganic precursors (yttrium and aluminum chloride). The preparation of the gel was carried out in an oven-dried glassware. The AlCl3, YCl3 and ethanol were reacted in reflux under argon atmosphere. Europium III chloride was added as a structural probe. The powder was dried and heat-treated in modified microwaves. The samples were pre-treated at 50 and 800 C during I h and then heated in microwaves for 30 s, 2 and 4 min. The formation process and structure of the powders were studied by means of X-ray diffraction (XRD), photoluminescence (PL) and transmission electronic microscopy (TEM). XRD presents only picks corresponding to the YAG phase and confirmed by TEM. PL date showed that the YAG phase was formed in 2 min with the samples pre-treated at 50 C. For the samples pretreated at 800 degrees C, the YAG phase appears in 30s. The excitation spectra present a maximum of 394 nm corresponding to the L-5(6) level and emission spectra of Eu III ion present bands characteristic transitions arising from the D-5(0) -> F-7(J) (J= 1, 2, 3, 4) monifolds excited at their maximum. The magnetic dipole D-5(0) -> F-7(1) transition presents more intensity than the electric dipole D-5(0) -> F-7(2) transition. This methodology showed efficiency in obtaining YAG phase. (c) 2006 Elsevier B.V. All rights reserved.

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Pós-graduação em Alimentos e Nutrição - FCFAR

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Second Edition. Pp.5-61 General Surgical Necessities, Gauze, Antiseptic Sundries, Surgical Sundries, Rubber Bandages, Catheters, Bougies, Splints, Tents, Emergency Bags, Surgeon's Needles, Operating Instruments, Amputating, Forceps, Aspiration, Cases, Catheters and Directors, Pocket Case Instruments, Dissecting and Post-Mortem Pp.62-118 General Operating - Osteotomy, Mastoid, Trephining, Eye Instruments, Aural, Nasal, Mouth and Throat, Tooth Forceps, Laryngoscopic Sets, Hydraulic Air Compressor, Variocele, Genito Urinary Pp. 119-167 Genito Urinary-Lithotrity, Alimentary, Anal and Rectal, Gynaecological, Pessaries, Microscopes, Syringes Pp.168-205 Chemical Apparatus and Glassware, Physician's Cabinets, Office Furniture, Operating Chairs and Tables, Hospital Beds, Cautery, Electrolytic, Batteries Pp.206-246 Cases, Varicose, Braces, Abdominal Supporters, Trusses, Invalid Chairs and Supplies, Sterilizers, Saddle-Bags, Deformity Apparatus Advertisements: Bandages, Abdominal Supporters, Rubber Supplies, Bags, Batteries, Cotton, Microscopes, Hypodermic Tablets, Atomizers, Furniture, Sterilizers, Syringes

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In this work, an analytical method was developed for the determination of pharmaceutical drugs inbiosolids. Samples were extracted with an acidic mixture of water and acetone (1:2, v/v) and supportedliquid extraction was used for the clean-up of extracts, eluting with ethyl acetate:methanol (90:10, v/v).The compounds were determined by gas chromatography?tandem mass spectrometry using matrix-match calibration after silylation to form their t-butyldimethylsilyl derivatives. This method presentsvarious advantages, such as a fairly simple operation for the analysis of complex matrices, the use ofinexpensive glassware and low solvent volumes. Satisfactory mean recoveries were obtained with thedeveloped method ranging from 70 to 120% with relative standard deviations (RSDs) ? 13%, and limitsof detection between 0.5 and 3.6 ng g?1. The method was then successfully applied to biosolids samplescollected in Madrid and Catalonia (Spain). Eleven of the sixteen target compounds were detected in thestudied samples, at levels up to 1.1 ?g g?1(salicylic acid). Ibuprofen, caffeine, paracetamol and fenofibratewere detected in all of the samples analyzed.

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Professor Dwight M. Smith demonstrates proper procedures for accurate preparation and handling of solutions for analytical chemistry, including the analytical balance, volumetric glassware, and avoiding contamination. This video provides an opportunity to learn from a master of the techniques.