Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy

The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established.     

Three-dimensional numerical investigation of film boiling by the lattice Boltzmann method

A three-dimensional lattice Boltzmann model is presented to simulate the film-boiling phenomenon. Single- and multimode film boilings are investigated. The flow and temperature fields around the vapor phase are obtained for various Jakob numbers. Furthermore, the effects of Jakob number on the Nusselt number and vapor tip velocity are investigated. The results show that on increasing the Jakob number, the bubble tip velocity increases while the Nusselt number decreases. Furthermore, it is found that in multimode film boiling, the peak and trough values of the local Nusselt number happen at the bubble position and the gap valleys between adjacent bubbles, respectively.     

Investigation on minimum quantity lubricant-MQL grinding of 100Cr6 hardened steel using different abrasive and coolant–lubricant types

Large quantities of coolant–lubricants are still widely used in the metal working industry, generating high consumption and discard costs and impacting the environment. Alternatives to current practices are getting more serious consideration in response to environmental and operational cost pressures. In the grinding process, promising alternatives to conventional dry and fluid coolant applications are minimum quantity lubrication (MQL) or near dry grinding process. Despite several researches, there have been a few investigations about the influence of different types of coolant–lubricants and grinding wheels on the process results. The current study aims to show the effects of the above parameters on grinding performance such as grinding forces and surface quality. The tests have been performed in presence of fluid, air jet and eleven types of coolant–lubricants, as well as, in dry condition. The grinding wheels employed in this study were vitrified bond corundum, resin bond corundum and vitrified bond SG wheels. The results indicate that SG wheels and MQL oils have potential for the development of the MQL process in comparison to vitrified and resin bond corundums and water miscible oils. Also, the lowest thermal damages, material side flow on the ground surface and wheel loading were generated by using the SG grinding wheel in MQL grinding process.     

Using computer simulation techniques to design a tellurium-123 target for <Superscript>123</Superscript>I production

The production of ¹²³I from ¹²³Te by the ^l23Te(p, n)¹²³I reaction at various target enrichments (99.9, 91, 85.4, and 70.1%) was simulated using ALICE and SRIM programs. The ¹²³I production feasibility by the above reaction was evaluated. The calculations give more accurate results for proton beam energy of less than 30 MeV. The cross sections of all tellurium reactions with proton were calculated at 0–30 MeV proton beam energy with ALICE program, and the yield of ¹²³I was calculated by analytical methods. Our prediction for ¹²³I production via bombardment of ¹²³Te (99.9%) with a proton beam energy of 5–15 MeV is about 7.2 mCi μA⁻¹ h⁻¹. Published in Russian in Radiokhimiya, 2008, Vol. 50, No. 5, pp. 460–463. The text was submitted by the authors in English.     

Protein Kinase C as a Therapeutic Target in Non-Small Cell Lung Cancer

Driver-directed therapeutics have revolutionized cancer treatment, presenting similar or better efficacy compared to traditional chemotherapy and substantially improving quality of life. Despite significant advances, targeted therapy is greatly limited by resistance acquisition, which emerges in nearly all patients receiving treatment. As a result, identifying the molecular modulators of resistance is of great interest. Recent work has implicated protein kinase C (PKC) isozymes as mediators of drug resistance in non-small cell lung cancer (NSCLC). Importantly, previous findings on PKC have implicated this family of enzymes in both tumor-promotive and tumor-suppressive biology in various tissues. Here, we review the biological role of PKC isozymes in NSCLC through extensive analysis of cell-line-based studies to better understand the rationale for PKC inhibition. PKC isoforms α, ε, η, ι, ζ upregulation has been reported in lung cancer, and overexpression correlates with worse prognosis in NSCLC patients. Most importantly, PKC isozymes have been established as mediators of resistance to tyrosine kinase inhibitors in NSCLC. Unfortunately, however, PKC-directed therapeutics have yielded unsatisfactory results, likely due to a lack of specific evaluation for PKC. To achieve satisfactory results in clinical trials, predictive biomarkers of PKC activity must be established and screened for prior to patient enrollment. Furthermore, tandem inhibition of PKC and molecular drivers may be a potential therapeutic strategy to prevent the emergence of resistance in NSCLC.     

Inventory lot-sizing with supplier selection using hybrid intelligent algorithm

In supply chain management (SCM), multi-product and multi-period models are usually used to select the suppliers. In the real world of SCM, however, there are normally several echelons which need to be integrated into inventory management. This paper presents a hybrid intelligent algorithm, based on the push SCM, which uses a fuzzy neural network and a genetic algorithm to forecast the rate of demand, determine the material planning and select the optimal supplier. We test the proposed algorithm in a case study conducted in Iran.     

POLAROGRAPHIC CHARACTERIZATION OF AROMATIC STRUCTURES IN COAL LIQUID PRODUCTS

Reducible aromatic species in coal liquid products from five major processes (Synthoil, FMC COED, HRI H-Coal, PAMCO SRC, and Catalytic Inc. SRC) together with solvent elution chromatography fractions of a selected asphaltene has been evaluated. The half-wave potentials measurments are found to be consistant with other methods. The total polarographic reduction of measurement per average molecule for Synthoil solvent fractions, as measured by diffusion constant (i_d/C), increases in the following manner: gas oil → resin → asphaltene → carbene → carboid. The same trend was observed when color indices (I) and refractive indices (n₂₅) were individually studied.     

Probing effects of alternately‐embedded phenoxy phenyl lateral groups on properties of novel aromatic poly(ether‐urea)s

A new class of alternate aromatic poly(ether‐urea)s having bulky phenoxy phenyl lateral groups was prepared by the reaction of 2,2′‐bis[(p‐phenoxy phenyl)]‐4,4′‐diaminodiphenyl ether (PPAPE) with two diisocyanates, isophorone diisocyanate and 2,4‐tolylene diisocyanate. The limited viscosity values as well as M _n and M _w values of the resulting polymers were determined. The resulting poly(ether‐urea)s could be easily cast into optically‐transparent, flexible, and light color films. The cut‐off wavelength values and the percentage of transmittance at 800 nm were found to be at about 415 nm and 85%, respectively. PPAPE‐derived poly(ether‐urea)s showed a low‐crystallinity and had excellent solubility in polar organic solvents. T_onset, T_g, T_d5%, and T_d10% values of the PPAPE‐derived polymers measured from their DSC and TGA thermograms were up to 270, 280, 315, and 340°C, respectively. Surface morphology of the resulted poly(ether‐urea)s were also evaluated by their scanning electron microscopy images. Excellent organo‐solubility, satisfactory film quality, moderate T_g values, and good thermal stability make this class of poly (ether‐urea)s promising high‐performance polymeric materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

An intelligent hybrid meta-heuristic for solving a case of no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines

This paper addresses the problem of no-wait two-stage flexible flow shop scheduling problem (NWTSFFSSP) considering unrelated parallel machines, sequence-dependent setup times, probable reworks and different ready times to actualize the problem. The performance measure used in this study is minimizing maximum completion time (makespan). Because of the complexity of addressed problem, we propose a novel intelligent hybrid algorithm [called hybrid algorithm (HA)] based on imperialist competitive algorithm (ICA) which are combined with simulated annealing (SA), variable neighborhood search (VNS) and genetic algorithm (GA) for solving the mentioned problem. The hybridization is carried out to overcome some existing drawbacks of each of these three algorithms and also for increasing the capability of ICA. To achieve reliable results, Taguchi approach is used to define robust parameters' values for our proposed algorithm. A simulation model is developed to study the performance of our proposed algorithm against ICA, SA, VNS, GA and ant colony optimization (ACO). The results of the study reveal the relative superiority of HA studied. In addition, potential areas for further researches are highlighted.     

The effect of type of atmospheric gas on milling behavior of nanostructured Ti6Al4V alloy

Recently fabrication of titanium alloys through solid state processes such as mechanical alloying has been greatly taken into consideration. In the present investigation the effects of common atmospheric impurities, oxygen and nitrogen, on the fabrication procedure and milling behavior of nanostructured Ti–6Al–4V alloy during mechanical alloying (MA) was studied. In this regards, elemental powders were milled under three different protective atmospheres of air, 90% and 99.998% pure Argon. Results indicated that, samples milled under Ar with 90% purity featured the best behavior and reached a nanostructure and subsequent amorphous state in shorter time periods. This was considered to be due to Ti lattice distortion made by interstitial element such as O₂ and N₂.