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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Measurements of halogenated organic compounds near the tropical tropopause

The amount of organic chlorine and bromine entering the stratosphere have a direct influence on the magnitude of chlorine and bromine catalyzed ozone losses. Twelve organic chlorine species and five organic bromine species were measured from 12 samples collected near the tropopause between 23.8 deg N and 25.3 deg N during AASE 2. The average mixing ratios of total organic chlorine and total organic bromine were 3.50 +/- 0.06 ppbv and 21.1 +/- 0.8 pptv, respectively. CH3Cl represented 15.1% of the total organic chlorine, with CFC 11 (CCl3F) and CFC 12 (CCl2F2) accounting for 22.6% and 28.2%, respectively, with the remaining 34.1% primarily from CCl4, CH3CCl3, and CFC 113 (CCl2FCClF2). CH3Br represented 54% of the total organic bromine. The 95% confidence intervals of the mixing ratios of all but four of the individual compounds were within the range observed in low and mid-latitude mid-troposphere samples. The four compounds with significantly lower mixing ratios at the tropopause were CHCl3, CH2Cl2, CH2Br2, and CH3CCl3. The lower mixing ratios may be due to entrainment of southern hemisphere air during vertical transport in the tropical region and/or to exchange of air across the tropopause between the lower stratosphere and upper troposphere.

Schauffler, S. M.↗
NASA NTRS1993

Measurements of Halogenated Organic Compounds near the Tropical Tropopause

The amount of organic chlorine and bromine entering the stratosphere have a direct influence on the magnitude of chlorine and bromine catalyzed ozone losses. Twelve organic chlorine species and five organic bromine species were measured from 12 samples collected near the tropopause between 23.8 deg N and 25.3 deg N during AASE 2. The average mixing ratios of total organic chlorine and total organic bromine were 3.50 +/- 0.06 ppbv and 21.1 +/- 0.8 pptv, respectively. CH3Cl represented 15.1% of the total organic chlorine, with CFC 11 (CCl3F) and CFC 12 (CCl2F2) accounting for 22.6% and 28.2%, respectively, with the remaining 34.1% primarily from CCl4, CH3CCl3, and CFC 113 (CCl2FCClF2). CH3Br represented 54% of the total organic bromine. The 95% confidence intervals of the mixing ratios of all but four of the individual compounds were within the range observed in low and mid-latitude midtroposphere samples. The four compounds with significantly lower mixing ratios at the tropopause were CHCl3, CH2Cl2, CH2Br2, and CH3CCl3. The lower mixing ratios may be due to entrainment of southern hemisphere air during vertical transport in the tropical region and/or to exchange of air across the tropopause between the lower stratosphere and upper troposphere.

Schauffler, S. M.↗
DOE OSTI2011

Synthesis and characterization of the La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} system and the fluorinated phases La{sub 1-x}Sr{sub x}FeO{sub 3-x}F{sub x}

The oxyfluorides La{sub 1-x}Sr{sub x}FeO{sub 3-x}F{sub x} have been prepared by fluorination of the precursor oxides La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} via a low temperature route using poly(vinylidene fluoride) (PVDF). The structures of the oxides and oxyfluorides were investigated in detail by the Rietveld analysis of powder diffraction data. The oxyfluorides crystallize in the space group Pnma for 0<x{<=}0.9 (SrFeO{sub 2}F itself is cubic, space group Pm-3m) and show a sort of two-step structural distortion for decreasing x. Furthermore, a structural comparison of the oxyfluorides with the oxides is given, revealing an increase of the volume per La{sub 1-x}Sr{sub x}FeX{sub 3} unit during fluorination, of which the magnitude highly depends on the value of x. - Graphical abstract: The crystal structures of the perovskites La{sub 1-x}Sr{sub x}FeO{sub 3-x}F{sub x} for x=0.8 (a), 0.5 (b) and 0.1 (c). Highlights: > Oxyfluorides La{sub 1-x}Sr{sub x}FeO{sub 3-x}F{sub x} were prepared via low temperature fluorination using PVDF. > A structural investigation of the compounds La{sub 1-x}Sr{sub x}FeO{sub 3-x}F{sub x} is presented in detail. > Differences in structure are discussed in comparison with the precursor oxides La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}}.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Stabilization of positive charge on polytetrafluoroethylene electret films treated with titanium-tetrachloride vapor

The surface of polytetrafluoroethylene films was treated with titanium-tetrachloride vapor. The treatment was carried out in a flow reactor by means of molecular-layer deposition, a method from the arsenal of chemical nanotechnology. X-ray photoelectron spectroscopy reveals that such a treatment results in considerable changes in the chemical composition at and near the surface of the fluoropolymer film. Both, defluorination and oxidation of the surface were observed. At the same time, samples treated with titanium tetrachloride show a significant enhancement in the thermal stability of the positive homocharge. The thermally stimulated surface-potential-decay curves were observed to shift to higher temperatures by more than 100 deg. C

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2011

Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound-color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Results of a Seven-Year, Single-Centre Experience of the Long-Term Outcomes of Bovine Ureter Grafts Used as Novel Conduits for Haemodialysis Fistulas

Purpose: To report the long-term outcomes of bovine ureter grafts as novel conduits for haemodialysis fistulas. Materials and Methods: Thirty-five patients underwent placement of a total of 40 SynerGraft 100 (SG100; CryoLife Europa{sup Registered-Sign}, Guildford, UK) bovine ureter grafts between April 2002 and February 2009. Prospective data were collected on all patients, including active surveillance with blood flow studies and 6-monthly duplex ultrasound studies. Main outcome measures were primary and secondary patency rates. Results: Mean follow-up time was 97 weeks (range 4-270). Thirteen patients died from unrelated causes during the study period; 12 of these patients had a functioning graft at the time of death. Five patients underwent transplantation, and all had a functioning graft at transplantation. Twelve patients had a functioning graft at the end of the study period. One hundred and ten stenoses were detected, and 97 venoplasty procedures were performed. Of the stenoses, 41.8% were located at the venous anastomosis, 12.7% within the graft, 17.3% in the outflow veins, and 28.1% in central veins. No arterial stenoses were detected. Primary patency rates were 53% at 6 months and 14% at 1 year. Secondary patency rates were 81% at 6 months, 75% at 1 year, and 56% at 2 years. Conclusions: Active surveillance and intervention was able to achieve satisfactory long-term secondary patency for these novel conduits compared with those made of PTFE seen in other studies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Low temperature fluorination of Sr{sub 3}Fe{sub 2}O{sub 7-x} with polyvinylidine fluoride: An X-ray powder diffraction and Moessbauer spectroscopy study

Fluorination of the Ruddlesden Popper phase, Sr{sub 3}Fe{sub 2}O{sub 7-x} by heat treatment with polyvinylidine fluoride (PVDF) gives a range of novel oxide fluoride compounds. Fluorination with 1 mol equivalent PVDF leads to a filling of the normal Ruddlesden Popper structure anion sites and a material of composition Sr{sub 3}Fe{sub 2}O{sub 5+x}F{sub 2-x} (x Almost-Equal-To 0.28(4)) which contains both Fe{sup 4+} and Fe{sup 3+}. Increasing the amount of PVDF to 2 mol equivalent leads to an increase in anion content due to filling of half the interstitial sites within the structure, with iron being completely reduced to Fe{sup 3+} leading to a composition Sr{sub 3}Fe{sub 2}O{sub 4}F{sub 4}. An increase in the amount of PVDF to Almost-Equal-To 3 mol equivalent leads to a further increase in unit cell volume, attributed to complete filling of the interstitial sites and a composition Sr{sub 3}Fe{sub 2}O{sub 3}F{sub 6}. {sup 57}Fe Moessbauer spectra in the temperature range 10-300 K demonstrated the complexity of the magnetic interactions in each of the three phases which reflect different local compositions of oxygen and fluorine around the iron ions thus influencing the superexchange pathways. - Graphical abstract: Low temperature (375 Degree-Sign C) fluorination of Sr{sub 3}Fe{sub 2}O{sub 7-x} with poly(vinylidene fluoride) leads to the production of three new Ruddlesden Popper oxide fluorides with progressive filling of the anion sites within the structure. Highlights: Black-Right-Pointing-Pointer The fluorination of Sr{sub 3}Fe{sub 2}O{sub 7-x} using PVDF. Black-Right-Pointing-Pointer The control of the fluorine content with amount of PVDF used. Black-Right-Pointing-Pointer The synthesis of three new Fe based oxide fluorides. Black-Right-Pointing-Pointer The identification of the structures of these oxide fluorides.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Pull-Through Technique for Recanalization of Occluded Portosystemic Shunts (TIPS): Technical Note and Review of the Literature

Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction is an important problem after creation of shunts. Most commonly, TIPS recanalization is performed via the jugular vein approach. Occasionally it is difficult to cross the occlusion. We describe a hybrid technique for TIPS revision via a direct transhepatic access combined with a transjugular approach. In two cases, bare metal stents or polytetrafluoroethylene (PTFE)-covered stent grafts had been placed in TIPS tract previously, and they were completely obstructed. The tracts were inaccessible via the jugular vein route alone. In each case, after fluoroscopy or computed tomography-guided transhepatic puncture of the stented segment of the TIPS, a wire was threaded through the shunt and snared into the right jugular vein. The TIPS was revised by balloon angioplasty and additional in-stent placement of PTFE-covered stent grafts. The patients were discharged without any complications. Doppler sonography 6 weeks after TIPS revision confirmed patency in the TIPS tract and the disappearance of ascites. We conclude that this technique is feasible and useful, even in patients with previous PTFE-covered stent graft placement.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Use of PTFE Stent Grafts for Hemodialysis-related Central Venous Occlusions: Intermediate-Term Results

Purpose: To assess the safety and effectiveness of a polytetrafluoroethylene (PTFE) encapsulated nitinol stents (Bard Peripheral Vascular, Tempe, AZ) for treatment of hemodialysis-related central venous occlusions. Materials and Methods: Study design was a single-center nonrandomized retrospective cohort of patients from May 2004 to August 2009 for a total of 64 months. There were 14 patients (mean age 60 years, range 50-83 years; 13 male, 1 female). All patients had autogenous fistulas. All 14 patients had central venous occlusions and presented with clinical symptoms of the following: extremity swelling (14%, 2 of 14), extremity and face swelling (72%, 10 of 14), and face swelling/edema (14%, 2 of 14). There was evidence of access dysfunction with decreased access flow in 36% (5 of 14) patients. There were prior interventions or previous line placement at the site of the central venous lesion in all 14 patients. Results were assessed by recurrence of clinical symptoms and function of the access circuit (National Kidney Foundation recommended criteria). Results: Sixteen consecutive straight stent grafts were implanted in 14 patients. Average treated lesion length was 5.0 cm (range, 0.9-7 cm). All 14 patients had complete central venous occlusion (100% stenosis). The central venous occlusions were located as follows: right subclavian and brachiocephalic vein (21%, 3 of 14), right brachiocephalic vein (36%, 5 of 14), left brachiocephalic vein (36%, 5 of 14), and bilateral brachiocephalic vein (7%, 1 of 14). A total of 16 PTFE stent grafts were placed. Ten- or 12-mm-diameter PTFE stent grafts were placed. The average stent length was 6.1 cm (range, 4-8 cm). Technical (deployment), anatomic (<30% residual stenosis), clinical (resolution of symptoms), and hemodynamic (resolution of access dysfunction) success were 100%. At 3, 6, and 9 months, primary patency of the treated area and access circuit were 100% (14 of 14). Conclusions: This PTFE encapsulated stent graft demonstrates encouraging intermediate-term patency results for central vein occlusions. Further prospective studies with long-term assessment and larger patient populations will be required.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Structure and magnetic properties of the cubic oxide fluoride BaFeO{sub 2}F

Fluorination of the parent oxide, BaFeO{sub 3-{delta}}, with polyvinylidine fluoride gives rise to a cubic compound with a=4.0603(4) A at 298 K. {sup 57}Fe Moessbauer spectra confirmed that all the iron is present as Fe{sup 3+}. Neutron diffraction data showed complete occupancy of the anion sites, indicating a composition BaFeO{sub 2}F, with a large displacement of the iron off-site. The magnetic ordering temperature was determined as T{sub N}=645{+-}5 K. Neutron diffraction data at 4.2 K established G-type antiferromagnetism with a magnetic moment per Fe{sup 3+} ion of 3.95 {mu}{sub B}. However, magnetisation measurements indicated the presence of a weak ferromagnetic moment that is assigned to the canting of the antiferromagnetic structure. {sup 57}Fe Moessbauer spectra in the temperature range 10-300 K were fitted with a model of fluoride ion distribution that retains charge neutrality of the perovskite unit cell. - Graphical abstract: The cubic oxide fluoride of composition BaFeO{sub 2}F has been synthesised and characterised. Highlights: > Fluorination of BaFeO{sub 3-{delta}} with polyvinylidene fluoride gives a cubic oxide fluoride of composition BaFeO{sub 2}F. > BaFeO{sub 2}F adopts a canted antiferromagnetic structure and is different from the related phase of composition SrFeO{sub 2}F. > A model of fluoride ion distribution about iron in BaFeO{sub 2}F has been explored.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Use of external metabolizing systems when testing for endocrine disruption in the T-screen assay

Although, it is well-established that information on the metabolism of a substance is important in the evaluation of its toxic potential, there is limited experience with incorporating metabolic aspects into in vitro tests for endocrine disrupters. The aim of the current study was a) to study different in vitro systems for biotransformation of ten known endocrine disrupting chemicals (EDs): five azole fungicides, three parabens and 2 phthalates, b) to determine possible changes in the ability of the EDs to bind and activate the thyroid receptor (TR) in the in vitro T-screen assay after biotransformation and c) to investigate the endogenous metabolic capacity of the GH3 cells, the cell line used in the T-screen assay, which is a proliferation assay used for the in vitro detection of agonistic and antagonistic properties of compounds at the level of the TR. The two in vitro metabolizing systems tested the human liver S9 mix and the PCB-induced rat microsomes gave an almost complete metabolic transformation of the tested parabens and phthalates. No marked difference the effects in the T-screen assay was observed between the parent compounds and the effects of the tested metabolic extracts. The GH3 cells themselves significantly metabolized the two tested phthalates dimethyl phthalate (DMP) and diethyl phthalate (DEP). Overall the results and qualitative data from the current study show that an in vitro metabolizing system using liver S9 or microsomes could be a convenient method for the incorporation of metabolic and toxicokinetic aspects into in vitro testing for endocrine disrupting effects.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Percutaneous Palliation of Pancreatic Head Cancer: Randomized Comparison of ePTFE/FEP-Covered Versus Uncovered Nitinol Biliary Stents

The purpose of this study was to compare the clinical effectiveness of expanded polytetrafluoroethylene/fluorinated-ethylene-propylene (ePTFE/FEP)-covered stents with that of uncovered nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer. Eighty patients were enrolled in a prospective randomized study. Bare nitinol stents were used in half of the patients, and ePTFE/FEP-covered stents were used in the remaining patients. Patency, survival, complications, and mean cost were calculated in both groups. Mean patency was 166.0 {+-} 13.11 days for the bare-stent group and 234.0 {+-} 20.87 days for the covered-stent group (p = 0.007). Primary patency rates at 3, 6, and 12 months were 77.5, 69.8, and 69.8% for the bare-stent group and 97.5, 92.2, and 87.6% for the covered-stent group, respectively. Mean secondary patency was 123.7 {+-} 22.5 days for the bare-stent group and 130.3 {+-} 21.4 days for the covered-stent group. Tumour ingrowth occurred exclusively in the bare-stent group in 27.5% of cases (p = 0.002). Median survival was 203.2 {+-} 11.8 days for the bare-stent group and 247.0 {+-} 20 days for the covered-stent group (p = 0.06). Complications and mean cost were similar in both groups. Regarding primary patency and ingrowth rate, ePTFE/FEP-covered stents have shown to be significantly superior to bare nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer and pose comparable cost and complications. Use of a covered stent does not significantly influence overall survival rate; nevertheless, the covered endoprosthesis seems to offer result in fewer reinterventions and better quality of patient life.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Casimir microsphere diclusters and three-body effects in fluids

Our previous paper [Phys. Rev. Lett. 104, 060401 (2010)] predicted that Casimir forces induced by the material-dispersion properties of certain dielectrics can give rise to stable configurations of objects. This phenomenon was illustrated via a dicluster configuration of nontouching objects consisting of two spheres immersed in a fluid and suspended against gravity above a plate. Here, we examine these predictions from the perspective of a practical experiment and consider the influence of nonadditive, three-body, and nonzero-temperature effects on the stability of the two spheres. We conclude that the presence of Brownian motion reduces the set of experimentally realizable silicon-teflon spherical diclusters to those consisting of layered microspheres, such as the hollow core (spherical shells) considered here.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2011

Thermal decomposition of electronic wastes: Mobile phone case and other parts

Highlights: > Pyrolysis and combustion of different parts of mobile phones produce important quantities of CO and CO{sub 2}. > Naphthalene is the most abundant PAH obtained in the thermal treatment of mobile phones. > Higher combustion temperature increases the chlorinated species evolved. - Abstract: Pyrolysis and combustion runs at 850 {sup o}C in a horizontal laboratory furnace were carried out on different parts of a mobile phone (printed circuit board, mobile case and a mixture of both materials). The analyses of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorodibenzo-p-dioxin, polychlorodibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, phenol, styrene, and its derivatives had the highest yields. In nearly all the runs the same PAHs were identified, naphthalene being the most common component obtained. Combustion of the printed circuit board produced the highest emission factor of PCDD/Fs, possibly due to the high copper content.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Electrical and Surface Morphology of Polyvinylchloride Composites Filled with Aluminum Powder

In this work, the electrical and surface morphology of polyvinyl chloride (PVC) composites filled with different concentration of aluminum powder varying from 0 to 40 wt.% have been prepared by solution costing method. The electrical conductivity of these composites were investigated in the frequency range 100 Hz-10 MHz at room temperature. The conductivity of the composites system exhibited a strong frequency dependence particularly in the vicinity of percolation threshold (20 wt.%). It was observed that the electrical conductivity gradually increased with filler concentration and frequency and explained in terms of hopping conduction mechanism. The electrical conductivity of the composites obeys universal power law (i.e. {sigma} = Af{sup n}), where, n is power exponent. The scanning electron microscope (SEM) micrographs indicate the agglomeration of aluminum particles dispersed within the PVC at the higher aluminum concentration, yielding a conductive path through the composites. It is also corroborated with electrical conductivity result.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Secretory phospholipase A{sub 2}-mediated progression of hepatotoxicity initiated by acetaminophen is exacerbated in the absence of hepatic COX-2

We have previously reported that among the other death proteins, hepatic secretory phospholipase A{sub 2} (sPLA{sub 2}) is a leading mediator of progression of liver injury initiated by CCl{sub 4} in rats. The aim of our present study was to test the hypothesis that increased hepatic sPLA{sub 2} released after acetaminophen (APAP) challenge mediates progression of liver injury in wild type (WT) and COX-2 knockout (KO) mice. COX-2 WT and KO mice were administered a normally non lethal dose (400 mg/kg) of acetaminophen. The COX-2 KO mice suffered 60% mortality compared to 100% survival of the WT mice, suggesting higher susceptibility of COX-2 KO mice to sPLA{sub 2}-mediated progression of acetaminophen hepatotoxicity. Liver injury was significantly higher at later time points in the KO mice compared to the WT mice indicating that the abatement of progression of injury requires the presence of COX-2. This difference in hepatotoxicity was not due to increased bioactivation of acetaminophen as indicated by unchanged cyp2E1 protein and covalently bound {sup 14}C-APAP in the livers of KO mice. Hepatic sPLA{sub 2} activity and plasma TNF-{alpha} were significantly higher after APAP administration in the KO mice. This was accompanied by a corresponding fall in hepatic PGE{sub 2} and lower compensatory liver regeneration and repair ({sup 3}H-thymidine incorporation) in the KO mice. These results suggest that hindered compensatory tissue repair and poor resolution of inflammation for want of beneficial prostaglandins render the liver very vulnerable to sPLA{sub 2}-mediated progression of liver injury. These findings are consistent with the destructive role of sPLA{sub 2} in the progression and expansion of tissue injury as a result of continued hydrolytic breakdown of plasma membrane phospholipids of perinecrotic hepatocytes unless mitigated by sufficient co-induction of COX-2.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Kinetics of thermal de-chlorination of PVC under pyrolytic conditions

Highlights: Black-Right-Pointing-Pointer Several tests were performed in DTA/TGA for understanding the thermal behavior of pure PVC. Black-Right-Pointing-Pointer We did a kinetic model for the de-chlorination of PVC molecule. Black-Right-Pointing-Pointer A temperature of 340 Degree-Sign C was defined as the optimum temperature for breaking the bond of chlorine in the PVC molecule. Black-Right-Pointing-Pointer The experimental validation of this temperature, led to a removal rate of 99.9% chlorine. - Abstract: Although PVC-containing wastes are an important potential source of energy they are frequently disposed in landfill. In thermal treatment processes such as pyrolysis and gasification, the presence of poly(vinyl chloride) (PVC), a compound with 56.7% of chlorine, may cause problems concerned with environmental protection, as consequence of the formation of hydrochloric acid, chlorine gas and dioxins, as well as corrosion phenomena of the reactor/equipment materials. Thus, a possible solution may involve a previous removal of the chlorine from PVC containing waste through a pyrolysis process at low temperatures before the material being submitted to a subsequent thermal treatment, for energetic valorization. In this work, a kinetic model for the thermal decomposition of PVC has been developed, in view of its de-chlorination. DTA/TGA testing at different temperatures indicated a first order reaction and an activation energy of 133,800 J/mol. An almost completed de-chlorination reaction was obtained at 340 Degree-Sign C under an inert atmosphere. The resulted material is a C{sub n}H{sub n} type polymer with potential to be used in an energy recovery process. Validation test performed at laboratory scale indicate that the temperature of 340 Degree-Sign C enables the removal of {approx}99.9% of the chlorine present in PVC. The chloride can be fixed in the form of an aqueous solution of HCl or calcium chloride, driving to an alternative full process with environmental benefits and reduction of the costs associated to the PCV - containing materials/wastes management.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗