The effect of thermal treatment on the properties of expanded polystyrene

Expanded polystyrene (EPS) is a commonly used polymer in the packaging industry and for the thermal insulation of buildings. It has poor mechanical properties, which limit its application in some areas. A heat treatment was carried out on a sample of EPS, in order to improve its mechanical properties. The treatment consists of operations that combine the heating and cooling of the material. It is executed to improve the characteristics of the treated polymer and make it more favorable for use in new applications. In the case of EPS, this process changes the behavior of the polymer in a beneficial manner and maximizes its density and hardness. Indeed, the treated version shows interesting mechanical, tribological, and hygroscopic properties. This improvement was obtained mainly due to the morphological modification of the structure of EPS. Indeed, heat treatment leads to the creation of a polystyrene crust, which covers every EPS bead. This crust protects the cell structure of each bead against stretching and supports most of the load applied to the treated version of EPS. Thus, the treated EPS can be used not only for packaging and thermal insulation but also for more structural applications.     

The feasibility of new design of hybrid photovoltaic-thermal system – a theoretical approach

Hybrid photovoltaic thermal (PVT) collectors have been evaluated according to the physical features of commercial photovoltaic (PV) cells; therefore, their commercial application is limited. The Tedlar collector has good electrical insulating properties, resulting in reduction in electrical efficiency. A researcher found that a glazed PVT system without Tedlar was the best among others, showing a significant increase in the overall efficiency. Inspired by this finding, we thought to study, for the first time, the feasibility of a new PVT that has been built by modifying a commercial PV panel and retrofitting it with the integration of two tubes in glass above the PV cell pasted on a thin metal ribbon before PV encapsulation. A heat transfer modelling/simulation in 3D was performed using COMSOL Multiphysics software.

The results show that under the no-cooling situation, the PV cell temperature reaches 74.87°C and the electrical power dropped significantly to 0.113 for electrical efficiency of 0.15 at the reference conditions. The water flow velocity is determined so that the cell can be effectively cooled. The cell temperature variation reaches to 45.9°C for a flow velocity of 0.5m/s, an irradiation of 1000W/m² and ambient temperature equal to 20.15°C.     

Design and development of a data acquisition system for photovoltaic modules characterization

Testing photovoltaic generators performance is complicated. This is due to the influence of a variety of interactive parameters related to the environment such as solar irradiation and temperature in addition to solar cell material (mono-crystalline, poly-crystalline, amorphous and thin films). This paper presents a computer-based instrumentation system for the characterization of the photovoltaic (PV) conversion. It based on a design of a data acquisition system (DAQS) allowing the acquisition and the drawing of the characterization measure of PV modules in real meteorological test conditions.     

Comparison of sulphide corrosivity of sulphate‐ and non‐sulphate‐reducing prokaryotes isolated from oilfield injection water

The microbiologically influenced corrosion (MIC) of water injection systems by sulphate‐reducing prokaryotes (SRP) has caused many problems in the oil industry. These prokaryotes produce H₂S, which reacts aggressively with steel and is thus widely considered to be the main cause of bacterial corrosion of industrial oil equipment. However, current microbiological treatments and controls have not taken into account other groups of sulphidogenic prokaryotes, which also produce H₂S or its derivatives and with the same adverse effects of MIC. In the present work, sulphidogenic prokaryotes were isolated from water injection systems and identified by DNA sequencing. The identified species included sulphate‐reducing Desulfovibrio termitidis and non‐sulphate‐reducing Escherichia coli. Biocorrosion tests were carried out on API 5L grade X65 carbon steel. Electrochemical impedance spectroscopy, polarisation resistance, open circuit potential and weight loss were carried out. Steel corrosion resulting from the production of the metabolite H₂S by SRP and non‐SRP was observed, with sulphide generation by SRP much greater than that by non‐SRP. These results confirm the need to investigate and consider the role of not only SRP but also non‐SRP in order to improve the control over bacterial corrosion of oil‐industry equipment.     

Effect of electrical contact configuration on gap-states absorption spectra by photocurrent methods in hydrogenated amorphous silicon alloys

Sub-bandgap optical absorption in the low photon energy range (0.7–1.5 eV) has been measured on the same undoped hydrogenated amorphous silicon alloys, using both CPM and DBT techniques in gap-cell and Schottky barrier (direct and reverse bias) electrical contacts configurations. Significant differences in results, sometimes larger than those noticed in the literature, are observed between spectra. These discrepancies are interpreted in terms of photocurrent equations theory, density of gap states model and light-induced or Staebler–Wronski effect.     

Individual and combined effects of fumonisin B1 present in Fusarium moniliforme culture material and diacetoxyscirpenol or ochratoxin A in turkey poults

The individual and combined effects of feeding diets containing 300 mg fumonisin B1 (FB1), and 4 mg diacetoxyscirpenol (DAS) or 3 mg ochratoxin A (OA) were evaluated in two experiments using female turkey poults (Nicholas Large Whites) from day of hatch to 3 wk of age. When compared with controls, body weight gains were reduced 30% (Study 1) and 24% (Study 2) by FB1, 30% by DAS, 8% by OA, 46% by the FB1 and DAS combination, and 37% by the FB1 and OA combination. The efficiency of feed utilization was adversely affected by all treatments except FB1 in Experiment 2. Relative weights of the liver were significantly increased by all treatments except the DAS treatment. Serum concentrations of cholesterol were decreased and activities of aspartate aminotransferase and lactate dehydrogenase were increased and several hematological values were altered in poults fed FB1 alone and in combination with either DAS or OA. Results indicate additive or less than additive toxicity, but not toxic synergy, when poults are fed diets containing 300 mg FB1, and 4 mg DAS or 3 mg OA/kg of diet. The likelihood of encountering FB1, DAS, or OA at these concentrations in finished feed is small. However, under field conditions, other stress factors could alter the impact of these mycotoxins on the health and performance of poultry.     

Long-term consequences of intraoperative spillage of bile and gallstones during laparoscopic cholecystectomy

Laparoscopic cholecystectomy is associated with a higher incidence of iatrogenic perforation of the gallbladder than open cholecystectomy. The long-term consequences of spilled bile and gallstones are unknown. Data were collected prospectively from 1059 consecutive patients undergoing laparoscopic cholecystectomy over a 3-year period. Details of the operative procedures and postoperative course of patients in whom gallbladder perforation occurred were reviewed. Long-term follow-up (range 24 to 59 months) was available for 92% of patients. Intraoperative perforation of the gallbladder occurred in 306 patients (29%); it was more common in men and was associated with increasing age, body weight, and the presence of omental adhesions (each P < 0.001). There was no increased risk in patients with acute cholecystitis (P = 0.13). Postoperatively pyrexia was more common in patients with spillage of gallbladder contents (18% vs. 9%; P < 0.001). Of the patients with long-term follow-up, intra- abdominal abscess developed in 1 (0.6%) of 177 with spillage of only bile, and in 3 (2.9%) of 103 patients with spillage of both bile and gallstones, whereas no intra- abdominal abscesses occurred in the 697 patients in whom the gallbladder was removed intact ( P < 0.001). Intraperitoneal spillage of gallbladder contents during laparoscopic cholecystectomy is associated with an increased risk of intra-abdominal abscess. Attempts should be made to irrigate the operative field to evacuate spilled bile and to retrieve all gallstones spilled during the operative procedure.     

Contractile activity of circular smooth muscle in rats one year after small bowel transplantation: differing adaptive response of the jejunum and ileum to denervation

BACKGROUND: In this report we describe the establishment, characterization, and research utility of a cell line derived from a dog having a spontaneously occurring osteosarcoma. MATERIALS AND METHODS: Tumor samples were collected from a dog with a naturally occurring osteosarcoma and processed for light microscopy, electron microscopy, immunocytochemistry, immunohistochemistry, karyology, and cell culture. Established cells from passage 31 (COS31; canine Qsteosarcoma cells from passage 31) were inoculated subcutaneously between the scapula and in the right abdominal side of athymic nude mice and evaluated similarly. RESULTS: COS31 cells derived in cell culture and in nude mice had morphological and biochemical properties comparable in all respects to the original canine tumor specimen. CONCLUSIONS: The ability of COS31 cells to produce tumors in nude mice (i.e. a small animal model) typical of canine osteosarcoma (i.e. a large animal model) with a similar pathological and biological behavior (e.g. alkaline phosphatase and osteocalcin positive immunostaining, osteoid production, rapid growth, and wide spread metastases) demonstrates the potential utility of COS31 cells as a in vitro and in vivo model system in the development of new strategies in the treatment of human osteosarcoma.