Cyclodimerization of 1,3-Pentadiene with Homogeneous Nickel Catalyst

Piperylene concentrate is a complex mixture of 5-carbon unsaturated hydrocarbons obtained as by-products when naptha or gas oils are cracked. The major component in this mixture is 1,3-pentadiene. The cyclodimerization of 1,3-pentadience in piperylene concentrate by using a nickel catalyst was studied. Various types of ligands were used in the preparation of the nickel catalyst. The effect of each ligand on activity of the catalyst in dimerization of diene, on conversion, and on yield of reaction were investigated. The effect of reaction conditions, such as temperature, pressure, and reaction time, on conversion of monomer, yield of dimer, and selectivity of catalyst were determined. The activity of catalyst on domerization of pure 1,3-pentadiene and isoprene also were studied. Production of various by-products during cyclodimerization of 1,3-pentadiene in piperylene concentrate mixture was a major problem in separation of dimer from these by-products

Antecedents of Positive Word of Mouth and its Effects on Attitude toward Product

Regarding to interpersonal and informal nature of word of mouth, this advertising practice always is considered as a reliable communication source and a potential power playing a critical role in customers’ decision making process. According to the prominence of word of mouth in the customers’ decision making process, the present research tried to study some features of listener (background knowledge, purchase involvement) and some features of the speaker or the source (expertise, experience, evidences, and reliability) that cause listener to apply it encountering word of mouth by proposing a model. This is an applied study in term of goal and a descriptive-correlation study in term of methodology. Research statistical population included students of one of Tehran major government universities. Data collected using questionnaire and analyzed by structural equations model using Smart pls2 software. Research results showed that four features of listener are directly related to applying word of mouth by listener. Further, the two factors of purchase involvement and listener background knowledge only moderate the relationship among experience, reliability and the evidences presented by source by using word of mouth

Rigorous analysis of the topologically protected edge states in the quantum spin Hall phase of the armchair ribbon geometry

Studying the edge states of a topological system and extracting their topological properties is of great importance in understanding and characterizing these systems. In this paper, we present a novel analytical approach for obtaining explicit expressions for the edge states in the Kane-Mele model within a ribbon geometry featuring armchair boundaries. Our approach involves a mapping procedure that transforms the system into an extended Su-Schrieffer-Heeger model, specifically a two-leg ladder, in momentum space. Through rigorous derivation, we determine various analytical properties of the edge states, including their wave functions and energy dispersion. Additionally, we investigate the condition for topological transition by solely analyzing the edge states, and we elucidate the underlying reasons for the violation of the bulk-edge correspondence in relatively narrow ribbons. Our findings shed light on the unique characteristics of the edge states in the quantum spin Hall phase of the Kane-Mele model and provide valuable insights into the topological properties of such systems