Compression behaviour of hand-tufted carpets: Part I–Effect of short-term static and dynamic loading

The effect of static and dynamic loading on the compression characteristics of hand tufted carpets has been studied using two types of pile materials. Wool tufted carpets are found to show better retention of thickness. Higher tuft density is found to assist retention of thickness, while higher pile height results in more thickness loss. Thickness loss is also found to be more at the initial impacts, while the recovery rate is found to be more at the initial stag

Compression behaviour of hand-tufted carpets: Part II—Effect of cyclic compressive load

305-311The effect of cyclic compressive load on compression characteristics of wool and acrylic hand-tufted carpets has been studied. Wool carpets exhibit higher compression and recovery than the acrylic carpets with similar construction. Compression and matting decrease with an increase in pile density. Percentage recovery of the carpets is found to increase with increase in the number of compression cycle

Compression behaviour of hand-tufted carpets: Part II—Effect of cyclic compressive load

The effect of cyclic compressive load on compression characteristics of wool and acrylic hand-tufted carpets has been studied. Wool carpets exhibit higher compression and recovery than the acrylic carpets with similar construction. Compression and matting decrease with an increase in pile density. Percentage recovery of the carpets is found to increase with increase in the number of compression cycle.

Compression behaviour of hand-tufted carpets: Part I–Effect of short-term static and dynamic loading

139-144The effect of static and dynamic loading on the compression characteristics of hand tufted carpets has been studied using two types of pile materials. Wool tufted carpets are found to show better retention of thickness. Higher tuft density is found to assist retention of thickness, while higher pile height results in more thickness loss. Thickness loss is also found to be more at the initial impacts, while the recovery rate is found to be more at the initial stage

Anaerobic granular sludge as a biocatalyst for 1,3-propanediol production from glycerol in continuous bioreactors

1,3-propanediol (1,3-PDO) was produced from glycerol in three parallel Expanded Granular Sludge Blanket (EGSB) reactors inoculated with granular sludge (control reactor-R1), heat-treated granular sludge (R2) and disrupted granular sludge (R3) at Hydraulic Retention Times (HRT) between 3 and 24 h. Maximum 1,3-PDO yield (0.52 mol mol-1) and productivity (57 g L-1 d-1) were achieved in R1 at HRTs of 12 h and 3 h, respectively. DGGE profiling of PCR-amplified 16S rRNA gene fragments showed that variations in the HRT had a critical impact in the dominant community of microorganisms. However, no appreciable differences in the bacterial population were observed between R2 and R3 at low HRTs. Production of H2 was observed at the beginning of the operation, but no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors and represents a novel strategy to valorise glycerol generated in the biodiesel industry.The financial support given to Roberto Gallardo from Fundacao da Ciencia e da Tecnologia (ref SFRH/BD/42900/2008) is gratefully acknowledged. The authors thank the MIT- Portugal Program for the support given to R. Gallardo and C. Faria

Teeth of the red fox Vulpes vulpes (L., 1758) as a bioindicator in studies on fluoride pollution

An examination was made of fluoride content in the mandibular first molars of the permanent teeth of the red fox Vulpes vulpes living in north-west (NW) Poland. The teeth were first dried to a constant weight at 105°C and then ashed. Fluorides were determined potentiometrically, and their concentrations were expressed in dry weight (DW) and ash. The results were used to perform an indirect estimation of fluoride pollution in the examined region of Poland. The collected specimens (n = 35) were classified into one of the three age categories: immature (im, 6–12 months), subadult (subad, from 12 to 20 months) and adult (ad, >20 months). The mean concentrations (geometric mean) of fluoride were similar in the im and subad groups (230 and 296 mg/kg DW and 297 and 385 mg/kg ash, respectively), and significantly smaller than in the ad group (504 and 654 mg/kg, respectively, in DW and ash). Basing on other reports that the ∼400 mg/kg DW concentration of fluoride in bones in the long-lived wild mammals generally reflects the geochemical background, it was found that 57% of the foxes in NW Poland exceeded this value by 9% to 170%. This indirectly reflects a moderate fluoride contamination in the tested region