998 resultados para accumulated thermal units


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The purpose of this research is to explore the variability on the soil thermal conductivity -λ- after a prescribe fire, and to assess the effects of the ashes on the heat transfer once it"s were incorporated into the soil matrix. Sampling plot was located in the Montgrí Massif (NE of Spain). A set of 42 soil samples between surface and 5 cm depth was collected before and after the fire. To characterize the soil chemical and physical variables were analyzed. To determine the vari-ability on the soil λ a dry-out curve per scenario (before and after fire) was determined. SoilRho® method based on ASTM D-5334-08 which was validated by LabFerrer was used. Soil thermal conductivity has shown changes in their values. Indeed, in all moisture scenarios the values of soil λ decreased after soil was burnt. The critical point in the rela-tionship ϴ (λ) for the soil after fire which always was stronger than soil before to be burnt. Soil with"white" ashes showed a high thermal conductivity. An X-Ray diffractometry analysis allowed to clarify and to verify these results. To sum up, we could say that thermal conductivity presents changes when the scenario changes, i.e. before and after to be burnt. On the other hand, the volume of ashes incorporated on the soil increased the differences between no burnt and burnt soil, showing even some improvements on the heat transfer when water content started to govern the process.

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Objective: An evaluation and comparison is made of the thermal increment at different implant surfaces during irradiation with CO2 and ErCr:YSGG lasers. Study design: Five threaded and impacted implants with four types of surfaces were inserted in an adult pig rib: two implants with a hydroxyapatite surface (HA)(impacted and threaded, respectively), a machined titanium surface implant (TI mach), a titanium plasma spray surface implant (TPS), and a sandblasted, acid-etched surface implant (SBAE). A 0.5-mm diameter bone defect was made in the implant apical zone, and a type-K thermocouple (Termopar)® was placed in contact with the implant. The implants were irradiated in the coronal zone of each implant with a CO2 (4 W continuous mode) and an ErCr:YSGG laser (1.5 W, pulsed mode) first without and then with refrigeration. The temperature variations at the implant apical surface were recorded. Results: An apical temperature increase was recorded in all cases during CO2 and ErCr:YSGG laser irradiation without refrigeration. However, when the ErCr:YSGG was used with a water spray, a decrease in temperature was observed in all implants. The acid-etched and sandblasted surfaces were those most affected by the thermal changes. Conclusions: The ErCr:YSGG laser with a water spray applied to the sealing cap or coronal zone of the implants does not generate thermal increments in the apical surface capable of adversely affecting osseointegration and the integrity of the peri-implant bone tissue

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Analysis of stratigraphic terminology and classification, shows that time-related stratigraphic units, which by definition have a global extent, are the concern of international cornrnissions and committees of the intemational Union of Geological Sciences (IUGS) . In contrast, lithostratigraphic, and other closely related units, are regional in extent and are catalogued in the International Stratigraphic Lexicon (ISL), the last volume of which, was published in 1987. Tlie intemational Commission on Stratigraphy (ICS) is currently attempting to revitalize the publication of ISL, given that the information contained in published volumes has never been updated, and that there has been a significant increase in stratigraphic research in recent decades. The proliferation of named units in the South Pyrenean and Ebro Basin Paleogene is evaluated to illustrate the extent of the problem. Moreover, new approaches to stratigraphic analysis have led to the naming of genetic units according to similar guidelines followed in the naming of descnptive or lithostratigraphic units. This has led to considerable confusion. The proposal to revitalize the ISL is accepted as part of the solution, that should also include the publication of critica1 catalogues, and the creation of norms for genetic unit terminology.

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This master’s thesis handles an operating model for an electric equipment supplier conducted sale oriented energy audit for pumping, fan and other motor applications at power plants. The study goes through the largest factors affecting internal electricity use at a power plant, finds an energy audit –like approach for the basis of information gathering and presents the information needed for conducting the analysis. The model is tested in practice at a kraft recovery boiler of a chemical pulping mill. Targets chosen represent some of the largest electric motor applications in the boiler itself and in its fuel handling. The energy saving potential of the chosen targets is calculated by simulating the energy consumption of the alternatives for controlling the targets, and thereafter combining the information with the volume flow duration curve. Results of the research are somewhat divaricated, as all the information needed is not available in the automation system. Some of the targets could be simulated and their energy saving potential calculated quite easily. At some of the targets chosen the monitoring was not sufficient enough for this and additional measurements would have been needed to base the calculations on. In traditional energy audits, energy efficiency of pump and fan applications is not necessarily examined. This means that there are good possibilities for developing the now presented targeted energy audit procedure basis further.

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PURPOSE: Unlike in the outpatient setting, delivery of aerosols to critically ill patients may be considered complex, particularly in ventilated patients, and benefits remain to be proven. Many factors influence aerosol delivery and recommendations exist, but little is known about knowledge translation into clinical practice. METHODS: Two-week cross-sectional study to assess the prevalence of aerosol therapy in 81 intensive and intermediate care units in 22 countries. All aerosols delivered to patients breathing spontaneously, ventilated invasively or noninvasively (NIV) were recorded, and drugs, devices, ventilator settings, circuit set-up, humidification and side effects were noted. RESULTS: A total of 9714 aerosols were administered to 678 of the 2808 admitted patients (24 %, CI95 22-26 %), whereas only 271 patients (10 %) were taking inhaled medication before admission. There were large variations among centers, from 0 to 57 %. Among intubated patients 22 % (n = 262) received aerosols, and 50 % (n = 149) of patients undergoing NIV, predominantly (75 %) inbetween NIV sessions. Bronchodilators (n = 7960) and corticosteroids (n = 1233) were the most frequently delivered drugs (88 % overall), predominantly but not exclusively (49 %) administered to patients with chronic airway disease. An anti-infectious drug was aerosolized 509 times (5 % of all aerosols) for nosocomial infections. Jet-nebulizers were the most frequently used device (56 %), followed by metered dose inhalers (23 %). Only 106 (<1 %) mild side effects were observed, despite frequent suboptimal set-ups such as an external gas supply of jet nebulizers for intubated patients. CONCLUSIONS: Aerosol therapy concerns every fourth critically ill patient and one-fifth of ventilated patients.

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Thermal processes are widely used in small molecule chemical analysis and metabolomics for derivatization, vaporization, chromatography, and ionization, especially in gas chromatography mass spectrometry (GC/MS). In this study the effect of heating was examined on a set of 64 small molecule standards and, separately, on human plasma metabolite extracts. The samples, either derivatized or underivatized, were heated at three different temperatures (60, 100, and 250 °C) at different exposure times (30 s, 60 s, and 300 s). All the samples were analyzed by liquid chromatography coupled to electrospray ionization mass spectrometry (LC/MS) and the data processed by XCMS Online ( xcmsonline.scripps.edu ). The results showed that heating at an elevated temperature of 100 °C had an appreciable effect on both the underivatized and derivatized molecules, and heating at 250 °C created substantial changes in the profile. For example, over 40% of the molecular peaks were altered in the plasma metabolite analysis after heating (250 °C, 300s) with a significant formation of degradation and transformation products. The analysis of 64 small molecule standards validated the temperature-induced changes observed on the plasma metabolites, where most of the small molecules degraded at elevated temperatures even after minimal exposure times (30 s). For example, tri- and diorganophosphates (e.g., adenosine triphosphate and adenosine diphosphate) were readily degraded into a mono-organophosphate (e.g., adenosine monophosphate) during heating. Nucleosides and nucleotides (e.g., inosine and inosine monophosphate) were also found to be transformed into purine derivatives (e.g., hypoxanthine). A newly formed transformation product, oleoyl ethyl amide, was identified in both the underivatized and derivatized forms of the plasma extracts and small molecule standard mixture, and was likely generated from oleic acid. Overall these analyses show that small molecules and metabolites undergo significant time-sensitive alterations when exposed to elevated temperatures, especially those conditions that mimic sample preparation and analysis in GC/MS experiments.

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The presence of residues of antibiotics, metabolites, and thermal transformation products (TPs), produced during thermal treatment to eliminate pathogenic microorganisms in milk, could represent a risk for people. Cow"s milk samples spiked with enrofloxacin (ENR), ciprofloxacin (CIP), difloxacin (DIF), and sarafloxacin (SAR) and milk samples from cows medicated with ENR were submitted to several thermal treatments. The milk samples were analyzed by liquid chromatography-mass spectrometry (LC-MS) to find and identify TPs and metabolites. In this work, 27 TPs of 4 quinolones and 24 metabolites of ENR were found. Some of these compounds had been reported previously, but others were characterized for the first time, including lactose-conjugated CIP, the formamidation reaction for CIP and SAR, and hydroxylation or ketone formation to produce three different isomers for all quinolones studied.

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The bridged sulphate complex [Pd2 (C²,dmba) (µ-SO4) (SO2)2] has been obtained by reacting a saturated solution of SO2 in methanol and the cyclometallated compound [Pd(C²,N-dmba)(µ-N3)] 2; (dmba = N,N-dimethylbenzylamine), at room temperature for 24 h. Reaction product was characterized by elemental analysis, NMR comprising 13C{¹H} and ¹H nuclei and I.R. spectrum's measurements. Thermal behavior has been investigated and residual products identified by X-ray powder diffraction.

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When the compounds are heated in an inert atmosphere it can be verified the consecutive partial sublimation, fusion, partial volatilization and partial thermal decomposition of the anhydrous complexes. When in an oxidating atmosphere the above process is only verified to Cu(II) chelates. Anhydrous copper(II) complexes present a monoclinic structure in the b form and the volatilized compound in a a form. Zinc(II) and cadmium(II) hydrated complexes are isomorphous and they present different cell dimensions from those reported previously.

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The presence of residues of antibiotics, metabolites, and thermal transformation products (TPs), produced during thermal treatment to eliminate pathogenic microorganisms in milk, could represent a risk for people. Cow"s milk samples spiked with enrofloxacin (ENR), ciprofloxacin (CIP), difloxacin (DIF), and sarafloxacin (SAR) and milk samples from cows medicated with ENR were submitted to several thermal treatments. The milk samples were analyzed by liquid chromatography-mass spectrometry (LC-MS) to find and identify TPs and metabolites. In this work, 27 TPs of 4 quinolones and 24 metabolites of ENR were found. Some of these compounds had been reported previously, but others were characterized for the first time, including lactose-conjugated CIP, the formamidation reaction for CIP and SAR, and hydroxylation or ketone formation to produce three different isomers for all quinolones studied.

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Iron and arsenic oxide grains are coated with the conducting organic polymer polyaniline. The obtained samples were characterized by infrared spectroscopy, SEM, conducting measurements and thermogravimetry. The thermal stability of both oxides are increased. For As2O3 the sublimation temperature is increased from 165ºC in the pure oxide to 206ºC in the polymer modified sample. The pure Fe3O4 sample exhibits sublimation at 780ºC whereas the polyaniline coated oxide is stable until at least 1000ºC.