Fuzzy Modeling of Strength-Composition-Process Parameter Relationships of HSLA Steels

The effect of composition and process parameters on the mechanical properties of high-strength low-alloy (HSLA) steels is modeled by the application of fuzzy systems viz. Sugeno and Mamdani types. The fuzzy inference systems are found to be capable of interpreting the metallurgical relations between composition and process variables and yield strength described through some if-then rules. The predictability of the fuzzy inference systems is found to be moderate.     

Synergisms between matrices and ZSM-5 in FCC gasoline non-hydrogenating upgrading catalysts

This article describes a novel non-hydrogenating FCC gasoline upgrading catalyst system consisting of a kaolin/γ-Al₂O₃ binary-matrix and an active component zeolite HZSM-5. Different catalysts made from the different combinations of HZSM-5 with the three matrices (two kaolins and γ-Al₂O₃) or their binary mixtures were prepared and their catalytic performances were assessed in a continuously flowing fixed-bed reactor using FCC gasoline as feedstock. The results showed that compared with the single-matrix based HZSM-5 catalysts, the binary-matrix based HZSM-5 catalysts had much better catalytic performance. The characterization results of the acidity, specific area and pore structure properties of the catalysts revealed that the synergisms between the matrices and HZSM-5 in the acidity and pore distribution of the binary-matrix based catalysts accounted for their improved catalytic performance. Our results demonstrated that the non-hydrogenating catalyst system developed in the present investigation can convert olefins in FCC gasoline into aromatics that have higher research octane number (RON) and thus has potential application for FCC gasoline upgrading because of its excellent olefin reduction ability and RON preservability.     

Synergism and antagonism in mild steel corrosion inhibition by sodium dodecylbenzenesulphonate and hexamethylenetetramine

The inhibition effects of sodium dodecylbenzenesulphonate (SDBS) and hexamethylenetetramine (HA) on the corrosion of mild steel in sulphuric acid solution have been studied using weight loss, electrochemical impedance and Tafel polarisation measurements. For HA, a monotonous increase in inhibition efficiency is observed as a function of concentration. For SDBS, however, an optimum in the inhibition efficiency is observed for a concentration close to 250 ppm, which is ascribed to the formation of hemi-micellar aggregates that provoke inhibitor desorption from the metal/solution interface at higher concentrations. Upon mixing HA and SDBS, concentration regions showing synergistic and antagonistic inhibition behaviour are identified, and it is concluded that electrostatic interactions between adsorbate ions are likely responsible for both phenomena. Langmuir and Frumkin isotherms were tested for relevance in describing the adsorption behaviour of both HA and SDBS.     

两性孪联表面活性剂的合成及其协同效应

通过月桂醇与2-氯-2-氧-1,3,2-二氧磷杂环戊烷低温酯化反应及与N,N-二甲基十二胺在65℃下亲核溶剂中开环反应合成了两性孪联表面活性剂(C12H25OPO-(O)O(CH2)2(CH3)2N+C12H25,C12-C12),其临界胶束浓度为0.009 2 mmol/L,最低表面张力为25.61 mN/m。采用界面张力法考察了两性表面活性剂C12-C12在癸烷中与十二烷基硫酸钠(SDS)的协同作用。不加电解质时,二者混合胶束能产生协同作用,但在降低界面张力上不具备协同作用;在质量分数为7%的NaCl溶液体系中,电解质降低了SDS/癸烷的界面张力,促进了SDS向胶束中转移,复配体系C12-C12/SDS/癸烷/NaCl具有降低界面张力效率、形成胶束能力的协同作用。     

油相性质对水相中混合表面活性剂协同效应的影响

通过不同碳链长度的正构烷烃与石油磺酸盐－非离子表面活性剂和石油磺酸盐－十二烷基苯磺酸体系之间动态界面张力的研究,发现混合表面活性剂在降低界面张力能力方面的协同效应不仅与表面活性剂分子之间的相互作用有关,而且与油相性质密切相关。从表面活性剂分子亲水能力和亲油能力方面为协同效应提出了一个新的解释。     

Experimental studies on the extinction of methane/air cup-burner flames with gas–solid composite particles

Fire suppression effectiveness of gas–solid composite particles consisting of 2-bromo-3,3,3-trifluoropropene (BTP) and zeolite 13X was evaluated on a cup-burner apparatus with coflowing methane/air flame. A series of composite samples with the weight concentration of BTP (ω) varying from 1.0 to 12.0% were tested. For comparison, extinction measurements were also conducted using neat BTP and zeolite 13X, respectively. Results indicated that the composite particles on a mass basis were much more effective than that of BTP and zeolite 13X used alone. A synergistic effect was exhibited by the BTP/zeolite 13X composites, which was affected by the ω values. Furthermore, significantly reduced HF concentrations (<70 ppm) were detected in the suppression tests with the composite particles, in comparison to that of neat BTP (1436 ppm). The composite particles extinguished the flame through a blowoff process, in which the flame base oscillated, detached from the cup-burner rim and extinguished eventually. Mechanism of the composite particles in suppressing the cup burner flame was studied.     

Synergism between corrosion and wear on CoCrMo−Al2O3 biocomposites in a physiological solution

The use of metal matrix composite structures in biomedical implants can be a solution for decreasing the amount of degradation products. Thus, the present work aims to investigate the synergism between corrosion and wear on CoCrMo matrix 10% (vol) Al₂O₃ particle reinforced composites in phosphate buffer solution (PBS) at body temperature. Corrosion behavior was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization. Tribocorrosion tests were performed under open circuit potential, as well as under cathodic and anodic potentiostatic conditions using a reciprocating ball-on-plate tribometer. Results suggest that the addition of Al₂O₃ particles did not create a significant effect on corrosion behavior of CoCrMo alloy, however, it increased the wear resistance and decreased the corrosion kinetics when sliding in PBS solution.     

Surfactant (in situ)–Surfactant (Synthetic) Interaction in Na2CO3/Surfactant/Acidic Oil Systems for Enhanced Oil Recovery: Its Contribution to Dynamic Interfacial Tension Behavior

The effect of synthetic surfactant molecular structure on the dynamic interfacial tension (DIFT) behavior in Na₂CO₃/surfactant/crude oil was investigated. Three surfactants, a nonionic (iC₁₇(EO)₁₃), an alcohol propoxy sulfate (C_14–15(PO)₈SO₄), and sodium dodecyl sulfate (SDS) were considered in this study. Sodium tripolyphosphate (STPP) was added to ensure complete compatibility between brine and Na₂CO₃. In Na₂CO₃/iC₁₇(EO)₁₃/oil and Na₂CO₃/C_14–15(PO)₈SO₄/oil systems, a strong synergistic effect for lowering the dynamic interfacial tension was observed, in which the dynamic IFT are initially reduced to ultralow transient minima in the range 1.1 × 10^?3–6.6 × 10^?3 mNm^?1 followed by an increment to a practically similar equilibrium value of 0.22 mNm^?1 independent of Na₂CO₃ concentration (for iC₁₇(EO)₁₃) and to decreasing equilibrium values with increasing alkali concentrations (for C_14–15(PO)₈SO₄). The observed difference in the equilibrium IFT for the two systems suggest that in both systems, the mixed interfacial film is efficient in reducing the dynamic interfacial tension to ultralow transient minima (～10^?3 mNm^?1) but the mixed film soap‐iC₁₇(EO)₁₃ is much less efficient than the mixed film soap‐C_14–15(PO)₈SO₄ in resisting soap diffusion from the interface to the bulk phases. In both systems, the synergism was attributed, in part, to the intermolecular and intramolecular ion–dipole interactions between the soap molecules and the synthetic surfactant as well as to some shielding effect of the electrostatic repulsion between the carboxylate groups by the nearby ethylene oxide (13 EO) and propylene oxide (8 PO) groups in the mixed interfacial monolayer. SDS surfactant showed a much lower synergism relative to iC₁₇(EO)₁₃ and C_14–15(PO)₈SO₄, probably due to the absence of ion–dipole interactions and shielding effect in the mixed interfacial layer at the oil–water interface.     

Study of the synergism effect of a binary carbon system in the nanostructure of the gas diffusion electrode (GDE) of a proton exchange membrane fuel cell

We report on the use of dual carbon supports activated charcoal (AC) and Vulcan XC-72R (VC) as catalysts for the fabrication of a gas diffusion electrode. The electrocatalytic properties for the oxygen reduction reaction were evaluated in a sulfuric acid electrolyte using polarization curves and electrochemical impedance spectroscopy. The water uptake and oxygen permeability were also obtained, as were the performances of electrodes in a membrane electrode assembly. A binary support electrode exhibits better performance than the usual single support electrode, with the best performance being obtained when the mass ratio of the two carbons is 50:50.     

Development of resistance in stored grain pest,Trogoderma granarium (Everts) against deltamethrin and its effective control by synergistic toxicity of bifenthrin and chlorpyrifos

The current investigation was conducted to estimate the resistance level against deltamethrin in fourth and sixth instar larvae of Trogoderma granarium collected from wheat storage warehouses of Dera Ghazi Khan (DGK), Okara (OKR) and Gujranwala (GUW). Results showed that the fourth and sixth instar larvae of collected strains warehouses moderately resistant to deltamethrin compared with the same developmental stages of insecticide susceptible laboratory strain (LAB-S). Efficacies of bifenthrin, chlorpyrifos and their various combinations were analyzed against fourth and sixth instar larvae of different strains of pest populations to minimize the development of resistance against deltamethrin. LC_50s of bifenthrin against fourth and sixth instar larvae of all the four populations were recorded at low concentrations compared to deltamethrin. The LC₅₀ values of bifenthrin against fourth instar larvae of LAB-S, DGK, OKR and GUW populations were 359.32, 416.58, 524.01 and 598.91 ppm, respectively, while these values were 204.30, 262.98, 301.89 and 355.22 ppm against sixth instar larvae of those populations, respectively. Chlorpyrifos was found to be the most effective insecticide compared to bifenthrin and deltamethrin. The LC₅₀ values of chlorpyrifos were 189.33, 305.37, 376.30 and 459.15 ppm against fourth instar larvae of LAB-S, DGK, OKR and GUW populations, respectively, whereas for sixth instar larvae those values were 98.24, 129.61, 163.43 and 230.74 ppm, respectively. Various combinations of bifenthrin and chlorpyrifos viz., 1:1, 2:1, 3:1, 1:2 and 1:3 were also tested. Based on the values of LC₅₀ and relative toxic unit, 1:3 combination was observed as the most effective among all combinations. The LC₅₀ values of fourth instar larvae of all the four populations against each insecticide and their combinations were recorded at high concentration compared to that of sixth instar larvae. Results of current investigation need to be considered in present stored grain insect pest control program of warehouses in Punjab¹.