The effect of temperature and ventilation condition on the toxic product yields from burning polymers

A major cause of death or permanent injury in fires is inhalation of toxic gases. Moreover, every fire is unique, and the range of products, highly dependant on fire conditions, produces a wide variety of toxic and irritant species responsible for the most fire fatalities. Therefore, to fully understand each contribution to the toxicity it is necessary to quantify the decomposition products of the material under the test. Fires can be divided into a number of stages from smouldering combustion to early well‐ventilated flaming through to fully developed under‐ventilated flaming. These stages can be replicated by certain bench‐scale physical fire models using different fuel‐to‐oxygen ratios, controlled by the primary air flow, and expressed in terms of the equivalence ratio (the actual fuel/air ratio divided by the stoichiometric fuel/air ratio). This work presents combustion product yields generated using a small‐scale fire model. The Purser Furnace apparatus (BS7990 and ISO TS 19700) enables different fire stages to be created. Identification and quantification of combustion gases and particularly their toxic components from different fire scenarios were undertaken by continuous Fourier transform infrared spectroscopy. The relationship between type of the fire particularly the temperature and ventilation conditions and the toxic product yields for four bulk polymers, low‐density polyethylene, polystyrene (PS), Nylon 6.6 and polyvinyl chloride (PVC) is reported. For all the polymers tested, except PVC, there is a dramatic increase in the yield of products of incomplete combustion (CO and hydrocarbons) with increase in equivalence ratio, as might be expected. For PVC there is a consistently high level of products of incomplete combustion arising both from flame inhibition by HCl and oxygen depletion. There is a low sensitivity to furnace temperature over the range 650–850°C, except that at 650°C PS shows an unexpectedly high yield of CO under well‐ventilated conditions and PVC shows a slightly higher hydrocarbon yield. This demonstrates the dependence of toxic product yields on the equivalence ratio, and the lack of dependence on furnace temperature, within this range. Copyright © 2007 John Wiley & Sons, Ltd.     

The effects of Cr,Al, Ti,Mo, W,Ta, and Cb on the cyclic oxidation behavior of cast Ni-base superalloys at 1100 and 1150°C

A series of cast nickel-base y/y′ superalloys as systematically varied at two nonzero levels of Cr, Al, Ti, Mo, Cb, W, and Ta with nominally fixed levels of 10 at. % Co, 0.06 at. % C, 0.05 at. % Zr, and 0.05% B. A 1/4-replicate 2⁷-factorial statistical design supplemented by 18 additional alloys was used to estimate main effects and all two-factor interactions. The cyclic oxidation resistance was determined from specific weight change data as a function time for 1-hr cycles in static air at 1100 and 1150°C. A derived oxidation attack parameter, K_a, was fitted by multiple linear regression over the alloy sample space at each temperature. At the levels tested, Al was the most important alloy addition. The lowest K_a was achieved at the highest (13 at. %) test level of Al and the lowest (10 and 2 at. %, respectively) test levels of Cr and Ti. The results for the refractory metal additions were somewhat ambiguous, but the most oxidation-resistant composition was estimated to be 3 at. % Mo-1 at. % Cb-3 at. % W-3 at. % Ta for the compositions tested. X-ray diffraction analysis of the alloy scales indicated that at the lowest K_a value, most oxidation resistant alloys were associated with alumina-aluminate spinel formation at the high Al levels. Higher boron contents, which were unintentionally varied, were clearly detrimental even for the most resistant compositions. High boron contents apparently trigger nonprotective NiO formation. In addition, tri-rutile type oxides were found on all test alloys, but these were not considered to be harmful to oxidation resistance.     

Restricted range adaptive curve fitting

In this paper we present an algorithm for adaptively computing smooth piecewise polynomial approximations using restricted range uniform approximations on a finite point set. We also present several numerical examples and offer suggestions for the effective use of this algorithm. We have found the algorithm to be effective for approximating a wide class of functions, either with or without significant levels of noise. Furthermore, since the user of this algorithm actually defines tolerance bands within which the approximation will lie, the algorithm allows the user a great deal of flexibility and control over the shape of the resulting approximations.     

Suggestion rates and sociotechnical systems in Japanese versusAmerican factories: beyond quality circles

Available information for two samples of factory organizations on the US and Japan are compared. Japanese factories are found to differ systematically from those in America in terms of several characteristics. These include marketing outputs, input of materials, machine automation, methods of production, human resource development, motivating incentives, and willingness to work. Moreover, available data suggest that the Japanese plants are outperforming those in the American sample. It is proposed that one reason is the higher rate of suggestions by employees in Japan. Causes and consequences of suggestion rates in the two nations are studied     

Self-awareness-reducing effects of alcohol consumption.

Three experiments with 180 males examined the effects of alcohol consumption on the self-aware state. Based on a model proposed by J. G. Hull (see record 1982-05684-001), it was predicted that alcohol would reduce self-awareness. In Exp I, Ss consumed either alcohol or tonic and then gave short speeches about themselves. All Ss expected to consume alcohol. The speeches were coded for frequency of self-focused statements. In support of predictions, alcohol reduced the relative frequency of self-focused statements. Exp II replicated this finding and demonstrated that it did not depend on Ss' expectancies regarding the beverage they consumed. Exp III investigated a potential mechanism for these effects. Alcohol was proposed to reduce self-awareness by interfering with the encoding of self-relevant information. Using an incidental-memory paradigm, it was found that high-private self-conscious Ss recalled more self-relevant words than did low-self-conscious Ss under placebo conditions, thus replicating the findings of Hull and A. S. Levy (see record 1980-27166-001). (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incorporation in vivo of 1-14C-palmitic acid into placental and fetal liver lipids of the rabbit

The incorporation of free fatty acid into the placental and fetal liver lipids of rabbits was studied after fetal injections of albumin-bound 1-14C-palmitic acid. The fetuses were killed either 5--10 or 10--20 min after the injection. The placentas and livers were extracted for lipids and the specific activities of triglycerides (TG), phospholipids (PL), free fatty acids (FFA), monoglycerides (MG) and diglycerides (DG) measured. The lipids of the liver and placenta took up 17.0 and 3.6% of the dose, respectively, and of that liver TG accounted for 74% and the placental TG 34% of the label in each tissue. Most of the remaining counts were in the PL fraction with the rest more or less evely distributed between the FFA, DG and MG fractions. No activity was recorded in the cholesterol esters. The placental TG, PL, DG and MG specific activities reached the same level as that of the placental FFA, while in the liver these esters had higher specific activities (than the liver FFA). The liver TG, DG and PL had higher specific activities when compared with those of the placenta. The specific activity of the placental FFA was lower at 10--20 min than at 5--10 min; the opposite was seen for the placental TG. No time-related changes were seen in the liver lipids. It is concluded that (i) both placenta and fetal liver incorporate FFA into glycerides and PL; (ii) the liver incorporates FFA more rapidly and to a greater extent than the placenta; (iii) most of the FFA is incorporated into TG and to a lesser extent (PL; (iv) in both organs hydrolysis of PL or TG occurs. These results are discussed with reference to placental transport of FFA and fetal fat metabolism.