Carpet model

An alternative mechanism for loss of membrane integrity is via the solubilization of phospholipids by thionins." This revised version of the carpet model is based on the observation of a conserved binding site for phospholipids head groups in thionins, their tendency to form oligomers," " and small-angle X-ray scattering... 

Carpet model Model for pore-forming amphipathic peptides in which the peptide behaves much like a detergent. 

Not only do facial amphiphiles act at the oil/water interface, natural facial amphiphiles also interact strongly with lipid bilayers such as cell membranes. Depending on the nature of the facial amphiphile, its interaction with biomembranes can lead to membrane bending, to pore formation, or even complete dissolution of the membrane. The dissolution of membranes by facial amphiphiles leads to cell death, and therefore the secretion of bile acids to the intestine of vertebrates is tightly regulated. The carpet model describes the mechanism of membrane dissolution by facial amphiphiles. Pore formation and membrane bending by facial amphiphiles are described in the next sections. 

The carpet model was first described for the mode of action of the alpha-helical facial amphiphilic peptides dermaseptin and later for cecropins as well as LL-37. These compounds display antibiotic behavior... 

A process for the depolymerisation of Nylon 6 carpet fibre in the presenee of steam under medium pressure (800 to 1500 KpA, 100 to 200 psig) is described. The feasibility of the seheme was demonstrated using a small laboratory apparatus and the best run produced a 95% yield of crude eaprolaetam. The data obtained were used to construct a computer model of the process for both batch and continuous flow stirred reactors. 6 refs. 

Construction effects The effects of construction were less pronounced than the effects of color. In general, cut pile carpets had larger absorbances across the entire spectrum than did loop pile carpets, but the positions of the characteristic absorption peaks were not affected. As for color, accurate calibration models could be developed on second-derivative spectra as long as sufficient variation in carpet construction was included in the library. 

Uttle, J.C., Hodgson, A.T. and Gadgil, A.J. (1994) Modeling emissions of volatile organic-compounds from new carpets. Atmospheric Environment, 28 (2), 227-34. 

Hietaniemi et al. [76] used a prerelease version of FDS4 to model lire spread on several materials in several different configurations and compared the calculated results with experimental data. This is one of the most comprehensive (in terms of the number of materials and the number of different configurations simulated) large-scale flame spread modeling studies conducted to date. The materials simulated include spruce timber (SBI, room/corner, and 6 m cavity), medium density fiber board (SBI and room/corner), PVC wall carpet on gypsum board (SBI, room/corner), upholstered furniture (furniture calorimeter and ISO room), and polyethylene-sheathed cables in 6 m cavity. 

In the study of Hietaniemi et al. [76], the model reproduced well most of the experiments conducted on spruce, but the calculated HRR was sensitive to the back-face boundary condition in the SBI test and the observed decay in the HRR in the cavity experiment was not captured by the model. Modeled HRR for medium density fiberboard closely matched room/corner test data, whereas HRR in the SBI test was not reproduced as closely. The HRR of the PVC wall carpet was reproduced reasonably well in the SBI test, but was overpredicted in the room corner test, probably owing to the discrepancy between the back-face boundary condition in reality and in the model. For the upholstered chair, FDS underestimated the time to ignition and the peak HRR compared with experimental data for both the furniture calorimeter and ISO room cases. Finally, for the polyethylene-sheathed cables in the 6 m cavity, the modeled HRR matched the experimental data fairly closely. In general, the results of Hietaniemi et al. [76] are encouraging. 

Several other types of hand-held vacuum samplers have been used to collect dust from residential surfaces. One of these, the Baltimore Repair and Maintenance Study Cyclone Sampler (BRMCS) (Farfel et al 1994), has been evaluated against the HVFS. The BRMCS uses the same cyclone and catch bottle assembly as the HVS3, but a different nozzle and vacuum source. The vacuumed dust is sucked into the cyclone via a semi-rigid Tygon hose (2.54-cm o.d.) that is notched on the sampling end to simulate a nozzle. Suction is provided by a small, hand-held vacuum device (Royal Hand Vac , Model 553, 2 A). The collection efficiency for the BRMCS was determined to be 44.1 % n =6, s = 3.8) for plush uylou carpet, 61.1 % (n = 6, = 6.7) for level loop carpeting, 71.8-87.8 % n =6, s = 3.5) for upholstery and 84.7 % n = 3, s = 2.3) for wood surfaces (USEPA, 1996b). 

Individuals can take many simple steps to protect themselves from the harmful effects of noise pollution. If people must be around loud sounds, they can protect their ears with ear plugs or ear protectors. They can muffle sound by using acoustic ceiling tiles, draperies, carpets, and sound-absorbing furniture in their homes, offices, and schools. They can also buy quieter models of machines and let store owners and manufacturers know that they prefer quieter products. Individuals can also help their communities investigate noise pollution and develop regulations to reduce the problem locally. 

Other materials in waste that is thermally processed also were studied by pyrolytic techniques, typically with the purpose of regenerating the monomers or of obtaining other useful small molecules. For example, pyrolytic studies were performed for the evaluation of the possibilities for re-utilization of nylon carpet waste [7], the recycling of thermoset polymeric composites [8], the recovery of methyl methacrylate from poly(methyl methacrylate) waste [9], as well as for other raw material recovery from pyrolysis of plastic waste [10]. The results of incineration of various other types of waste also were studied at model scale [11, 12). These studies were applied to specific waste materials associated with the manufacturing process or to municipal solid waste [13-15)... 

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