جستجوی مقالات مرتبط با کلیدواژه « statistical analysis » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Considering the development of cosmetic products in Iran, the presence of heavy metals directly and indirectly (in the form of an organometallic color), side effects (skin allergies) and the risk of being carcinogenic have caused these colors to be considered and investigated by researchers. The purpose of this study, which was conducted by randomly selecting five Iranian brands in Tehran, is to determine the amount of heavy metals in the mentioned samples. This study was conducted on 20 samples from 4 brands and 5 types of selected products produced in the country. The concentration of heavy metals (lead, nickel, chromium, arsenic, mercury and cadmium) was measured using induced mass (ICP MASS) after performing the steps of acid digestion by plasma spectrometry. Statistical analysis was performed on the measured values, and the results showed that the concentration of heavy metals in 20 samples measured with three repetitions was less than 10 ppm and within the permissible limit. But the pollution level of brands is significantly different. Health risk assessment in exposure to heavy metals in terms of carcinogenicity and non-carcinogenicity was investigated in lipstick samples. The results showed that the risk of skin carcinogenesis through repeated use over time is serious and cannot be ignored.

In various countries, strict rules are considered for reducing sulfur in the fuels. Oxidative desulfurization is known as one of the best complementary methods for the hydro-desulfurization. In this paper, using the response surface methodology, the effects of initial sulfur concentration in the naphtha fuel, reaction temperature, and reaction time on the sulfur conversion were investigated in the presence of zeolite supported zinc Oxide catalyst. </em>Experiments were conducted at the conditions as follows: T=303.15-323.15 K, t=20-40 min, and initial sulfur concentration=150-250 ppm. </em>Analysis of variance showed that the linear factorial model well fitted the experimental data. All the parameters as well as the interaction between reaction time and temperature affected the response, significantly. Maximum sulfur conversion of 90% was achieved at the temperature of 320 K, reaction time of 40 min, and initial sulfur concentration of 244 ppm.</em>

Accurate evaluation of pore pressure and fracture pressure are key parameter in well planning and drilling operation. Estimation of these parameters has an important role in reduction in well costs. An inaccurate estimation of fracture gradient may jeopardize whole drilling operation and cause serious problems such as loss circulation and blowout. In this paper, the method of Gene Expression Programming (GEP) has used for developing a mathematical model for prediction of formation fracture pressure. Overburden pressure, pore pressure and Poisson ratio are independent variables in this model. Studied areas include two oil-bearing formations: Kangan and Upper-Dalan in an onshore field which is located near Persian Gulf. A separate model is presented for each formation by using well logging data from two wells. Models developed by using more than 4,300 well logging data from a well. Verification of these models is done with 6,000 data from second well in same formation. Statistical analyses confirm that the models are suitable for fracture gradient prediction so we can use them for estimation of fracture pressure.

Hypothis: Rubber powder with a very fine particle size, rough surface and very low impurities can be prepared by water jet technology. The use of this powder as a suitable additive in tyre compounds is very important from economic and environmental viewpoints.
Morphology of the water jet powder was investigated using SEM. The rubber powder was added to a SBR/BR-based tyre tread formulation and the curing behavior and mechanical properties of the resultant product were determined. A full factorial experimental design was also conducted to study simultaneously the effects of rubber powder, sulfur and carbon black levels on the curing and mechanical properties of tyre tread formulation. Furthermore, the modification effect of Vestenamer additive and curing agent on the formulation properties was investigated. When using design of experiments, for each property the regression models with linear and binary interaction terms on the basis of three variables were successfully developed and statistically validated.
Findings: The rubber powder showed a lowering effect on tensile properties, which was attributed to reduced crosslink density due to the sulfur migration from the rubber matrix to the powder phase. A small, but statistically significant negative effect on the aging, abrasion and resilience properties of rubber compound was also observed, However, the tear resistance and de Mattia crack growth were improved with increasing rubber powder content, that could be attributed to the lesser effect of rubber powder on the compound modulus. It was shown that with some increase in the curing agent, sulfur and accelerator dosage, it was possible to compensate for the tensile properties to some extent and for the abrasion, resilience and aging properties completely, whereas others remained relatively unchanged. It was also shown that except for abrasion, the Vestenamer processing aid had little improving effect in the presence of rubber powder.

One of the common methods for reservoir screeining in EOR projects is comparison of prosperous projects is comparison between successfulcarried out projects and available reservoirs in the whole world. Because of lack of similar samples in this method, some of reservoirs are not considered for injection, so casing of another EOR method is necessary. In this paper, at first, by combination of Experimental design and Compositional simulation, rock and fluid effective parameters are detected in N2 and CH4 gas injections for pressure maintenance in reservoirs. Then, indirect and interaction effect of these parameters are analyzed and compared for both gas injections. separately for both gases injection are analyzed and compared. Finally, for estimation of oil recovery factor, empirical correlation is proposed. This correlation is used for primary screening in N2 and CH4 injection projects.