Pyrolysis and combustion characteristics of typical waste thermal insulation materials.

Thermal insulation materials are important for building energy conservation, but their wastes have increased sharply. Furthermore, pyrolysis and combustion are increasingly utilized to dispose of solid wastes and convert them into value-added fuels. To better understand the pyrolysis and combustion characteristics of these materials, typical thermal insulation materials (expanded polystyrene (EPS) and extruded polystyrene (XPS)) were investigated by employing thermogravimetry and differential scanning calorimetry as well as cone calorimetry experiments. Pyrolysis behavior, kinetic parameters, pyrolysis index, thermodynamic parameters, endothermic properties and combustion parameters were estimated comprehensively. The results showed that EPS had better pyrolysis properties, while XPS had better combustion characteristics. Activation energies of EPS and XPS were 158.82 kJ/mol and 200.70 kJ/mol, respectively. Additionally, EPS had a higher pyrolysis stability index and comprehensive pyrolysis index, meaning a more intense reaction. Moreover, thermodynamic parameters indicated that the devolatilization products could be obtained easily from the two materials, and EPS and XPS could be converted into fuels. For the combustion, XPS had a smaller fire performance index and a larger fire growth index. These results can guide the reactor design and optimization for better converting polymer wastes into fuels and managing wastes.

Human facial allotransplantation: a 2-year follow-up study.

BACKGROUND: Progress in composite tissue allotransplantation could provide a new treatment for patients with severe facial disfigurements. We did a partial facial allotransplantation in 2006, and report here the 2 year follow-up of the patient. METHODS: The recipient, a 30-year-old man from China, had his face severely injured by a bear in October, 2004. Allograft composite tissue transplantation was done in April, 2006, after careful systemic preparation. The surgery included anastomosis of the right mandibular artery and anterior facial vein, whole repair of total nose, upper lip, parotid gland, front wall of the maxillary sinus, part of the infraorbital wall, and zygomatic bone. Facial nerve anastomosis was done during the surgery. Quadruple immunomodulatory therapy was used, containing tacrolimus, mycophenolate mofetil, corticosteroids, and humanised IL-2 receptor monoclonal antibody. Follow-up included T lymphocyte subgroups in peripheral blood, pathological and immunohistochemical examinations, functional progress, and psychological support. FINDINGS: Composite tissue flap survived well. There were three acute rejection episodes at 3, 5, and 17 months after transplantation, but these were controlled by adjustment of the tacrolimus dose or the application of methylprednisolone pulse therapy. Hepatic and renal functions were normal, and there was no infection. The patient developed hyperglycaemia on day 3 after transplantation, which was controlled by medication. INTERPRETATION: Facial transplantation could be successful in the short term, but the procedure was not without complications. However, promising results could mean that this procedure might be an option for long-term restoration of severe facial disfigurement.

Modeling and analysis of bench-scale pyrolysis of lignocellulosic biomass based on merge thickness.

The bench-scale pyrolysis of lignocellulosic biomass was investigated based on effect of thickness by both the experiment and numerical simulation. A critical thickness at which the two peaks of mass loss rate start to merge and the pyrolysis process is significantly accelerated, is paid attention in the fire propagation apparatus experiment at N2 atmosphere. A new method is put forward to predict the merge thickness by coupling the Gpyro pyrolysis model with the optimized chemical reaction parameters, moisture and changed volume in OpenFOAM. Eventually, the predicted equation of merge thickness at various external heat fluxes is obtained, which is basically the same with that of thermal thickness.

[Repair of facial and cervical scars with expanded deltopectoral flaps].

OBJECTIVE: To explore the methods for repair of facial and cervical scars after burn. METHODS: One hundred and two patients with facial and cervical scars as a result of burn injury were repaired by unilateral or bilateral deltopectoral flaps after expansion with pedicles. First, facial scars were excised and contractures were released to restore eye, mouth and nose to normal anatomical position. The facial scar flaps were overturned to join with the pedicles of deltopectoral flap for closing the wounds. The residual wounds were repaired by delayed flaps without pedicles 3 weeks later. RESULTS: Among 102 patients, the flaps survived well in 94 cases, and blood supply insufficiency was found in distal end of unilateral flap in 7 cases (depigmentation after primary healing ). Necrosis of unilateral flap occurred in one patient, and it healed after skin grafting. CONCLUSION: Expanded deltopectoral flap is efficacious procedure for repair of massive cervical and facial scars.

[Preparation of compound biodegradable matrices and growth of vascular endothelial cell on them].

OBJECTIVE: To prepare the compound biodegradable matrices, polyglycolic acid (PGA), polylactic acid (PLA) mesh and poly-beta-hydroxybutyrate(PHB) which precoated with collagen, and to observe the growth and differentiation of bovine vascular endothelial cells on these scaffolds. METHODS: By enzymatic digestion methods, bovine vascular endothelial cell (VEC) were isolated from calf thoracic aorta, then cultured and purified. PGA, PLA, PHB meshes were dipped into cross-linked type I collagen solution, dried under vacuum frozen condition. VEC were seeded into these scaffolds. The growth of VEC on scaffolds was analyzed by MTT method. RESULTS: The collagen, PGA/collagen, PLA/collagen scaffolds were elasticity and tenacity. VEC grew better on collagen, PGA/collagen, and PLA/collagen membranes than on the PHB/collagen one. CONCLUSION: The PGA/collagen scaffold has elasticity, plasticity and tenacity. VEC grow best on it. It is an ideal scaffold for tissue engineered vessel reconstruction for it integrating both advantages of biomaterials and degradable materials.