Synthesis and Characterization of New Poly(ether-amide-imide)/Amino-Functionalized Fe3O4 Nanocomposites

New poly(amide-imide)/amino functionalized Fe₃O₄ nanocomposites were successfully fabricated through solution intercalation technique. A poly(amide-imide) derived from an imide-containing diacid and ether linkage diamine was synthesized and characterized. Aiming to have better compatibility, the hydrophilic nature of Fe₃O₄@SiO₂ was changed into organophilic using N-[3-(trimethoxysilyl)propyl]ethylenediamine. The amino-functionalized Fe₃O₄ showed well dispersion in the poly(amide-imide) matrix. Thermal gravimetric analysis results indicated that char yields of the nanocomposites were improved. Microscale combustion calorimetry results showed that poly(amide-imide) had good flame retardancy and amino-functionalized Fe₃O₄ has further improved this property of poly(amide-imide).     

Cyano‐Substituted Oligothiophenes: A New Approach to n‐Type Organic Semiconductors

A series of α,ω‐cyano oligothiophenes with three to six rings, as well as seven β,β′‐substituted cyano terthiophenes have been synthesized using a palladium‐catalyzed coupling reaction via organotin or organozinc intermediates. The structure of an oliothiophene trimer has been determined by X‐ray crystallography; its space group is monoclinic (C2/c) with four molecules per unit cell (Z = 4). The molecules adopt the π–π stacking structure. UV‐vis spectra of these materials as thin films show a bathochromic shift compared to unsubstituted oligothiophenes. These bathochromic shifts are interpreted in the light of charge transfer exciton. Cyano end‐capped sexithiophene (CN‐6T‐CN) sandwiched between various metals (metal/CN‐6T‐CN/metal), to form Schottky diode structures, were fabricated by vapor deposition. The electron injection and rectification ratio strongly depend on the metal contact, namely the work function of the metal is compatible with the electron affinity of the organic material. The current–voltage results are compatible with n‐type conduction in CN‐6T‐CN.     

Synthesis and processing of PMMA carbon nanotube nanocomposite foams

Poly(methyl methacrylate) (PMMA) multi-walled carbon nanotubes (MWCNTs) nanocomposites were synthesized by several methods using both pristine and surface functionalized carbon nanotubes (CNTs). Fourier transform infrared (FTIR) spectroscopy was used to characterize the presence and types of functional groups in functionalized MWCNTs, while the dispersion of MWCNTs in PMMA was characterized using scanning electron microscopy (SEM). The prepared nanocomposites were foamed using carbon dioxide (CO₂) as the foaming agent. The cell morphology was observed by SEM, and the cell size and cell density were calculated via image analysis. It was found that both the synthesis methods and CNTs surface functionalization affect the MWCNTs dispersion in the polymer matrix, which in turn profoundly influences the cell nucleation mechanism and cell morphology. The MWCNTs are efficient heterogeneous nucleation agents leading to increased cell density at low particle concentrations. A mixed mode of nucleation mechanism was observed in nanocomposite foams in which polymer rich and particle rich region co-exist due to insufficient particle dispersion. This leads to a bimodal cell size distribution. Uniform dispersion of MWCNTs can be achieved via synergistic combination of improving synthesis methodology and CNTs surface functionalization. Foams from these nanocomposites exhibit single modal cell size distribution and remarkably increased cell density and reduced cell size. An increase in cell density of ∼70 times and reduction of cell size of ∼80% was observed in nanocomposite foam with 1% MWCNTs.     

Physical characterizations of semi-conducting conjugated polymer-CNTs nanocomposites

Carbon nanotubes (CNTs) were prepared using Alcholic Catalyst Chemical Vapor Deposition (ACCVD) technique in order to investigate the effects of their addition on the optical, electrical and mechanical properties of Poly(3-octylthiophene-2,5-diyl) (P3OT) matrix. The absorption spectra of the prepared CNTs and CNT-P3OT nanocomposites were measured in the spectral range 200 nm–3,000 nm at room temperature. The optical energy gap was determined from the obtained UV/Vis absorption spectrum. Optical results reveal that the prepared CNTs are almost single walled. Besides, the addition of CNTs to P3OT polymer matrix will decrease the optical energy gap and enhance the optical absorbance of P3OT matrix. On the other hand, the addition of CNTs to P3OT matrix will increase the electrical conductivity of P3OT matrix up to four orders of magnitude above the percolation threshold (0.44 wt% CNTs). Additionally, I–V characteristics indicate that the conduction mechanism is Ohmic at low applied voltage range while it is due to the trap charge limited at high applied voltage range. Furthermore, the behavior of dc conductivity with temperature was also investigated and the obtained results reveal that the activation energy decreases with CNTs content. Finally, mechanical results reveal that the elastic modulus values increase with the increasing of CNTs content in P3OT matrix.     

Improvement of physical characteristics of petroleum waxes by using nano-structured materials

Layered double hydroxides (LDHs) are a class of synthetic two-dimensional nano-structured anionic clays whose structure can be described as nano-layered ordered material. This study aims to use nano-layered materials as a host for organic guests having required functional groups such as azo-compounds to alter LDH surface properties from hydrophilic to hydrophobic and increase sorption capacity for sulfur and aromatic compounds through constructing nano-hybrid material. A large anionic pigment (phenyl azobenzoic sodium salt) has been intercalated into Zn-Al LDH and a complex system of supra-molecular host-guest interactions was formed.We have examined the unusual bi-functionality effects caused by hybridization for removing sulfur and aromatic compounds from petroleum waxes. Results clearly indicated that nano-layered material decreased sulfur content and mono-aromatic compounds of heavy slack wax. In the same run, it completely removed di-aromatic compounds. In the same trend, the nano-hybrid material showed high efficiency for removing aromatic and sulfur compounds from crude petrolatum. This leads to an improvement for the physical properties of heavy slack wax and crude petrolatum.     

Advances in the Research of Melatonin in Autism Spectrum Disorders: Literature Review and New Perspectives

Abnormalities in melatonin physiology may be involved or closely linked to the pathophysiology and behavioral expression of autistic disorder, given its role in neurodevelopment and reports of sleep-wake rhythm disturbances, decreased nocturnal melatonin production, and beneficial therapeutic effects of melatonin in individuals with autism. In addition, melatonin, as a pineal gland hormone produced from serotonin, is of special interest in autistic disorder given reported alterations in central and peripheral serotonin neurobiology. More specifically, the role of melatonin in the ontogenetic establishment of circadian rhythms and the synchronization of peripheral oscillators opens interesting perspectives to ascertain better the mechanisms underlying the significant relationship found between lower nocturnal melatonin excretion and increased severity of autistic social communication impairments, especially for verbal communication and social imitative play. In this article, first we review the studies on melatonin levels and the treatment studies of melatonin in autistic disorder. Then, we discuss the relationships between melatonin and autistic behavioral impairments with regard to social communication (verbal and non-verbal communication, social interaction), and repetitive behaviors or interests with difficulties adapting to change. In conclusion, we emphasize that randomized clinical trials in autism spectrum disorders are warranted to establish potential therapeutic efficacy of melatonin for social communication impairments and stereotyped behaviors or interests.     

Cognizance of Visual Design Management in Life-Cycle Project Management

This paper presents a unique approach to information management within a life-cycle project management model. Focus is shifted from the delivery of the physical facility to the creation of a business to service the project objectives employing concurrent engineering∕construction approaches. Typical life-cycle objectives are life-cycle cost and net worth, or cost/worth ratio. The definition and broad design of the facility and its components will be a collective responsibility, discharged by composite teams whose members are drawn from the respective participants. Their inputs are evaluated in real time against the above objectives. The traditional responsibility for detailing and conformity to the relevant codes and standards will still reside with the relevant design professionals. This paper introduces a visual design management system that has been developed to reflect the fundamentals of information and design management within the life-cycle project management paradigm.     

Re-engineering the Productivity Initiative Programme

This paper explains the fundamentals of the leadership-based education model, and proceeds to apply the relevant principles to re-engineer the Productivity Initiative Programme, run by the European Commission to re-train 3500 Russian executives. The authors considered the retraining of executives to constitute a project whose goals and delivery means were ambiguous at the commencement of the programme. They realized at the outset that success of any methodology would depend on the extent of empowerment of the participant executives achieved, and on the release of their creative energies, as well as time. The leadership-based project management approach was chosen to specifically respond to the empowerment of the participants and engage them positively in the definition of the goals, context of application and the delivery of the programme goals. Using the empowerment philosophy the authors set out to re-engineer the entire programme to make it project-based, while providing a structured learning experience that would achieve a paradigm shift in the mindsets of the participants without offending their cultural sensibilities. To create learning focus and continuity the authors chose to recommend preparation of business plans by the syndicate executives as the primary learning vehicle and as means of progress monitoring and performance evaluation. Business plans were to reflect the realities of Russia's business and cultural environment as perceived by the participants. Thus, learning through application (as part of a total internship experience), was deliberately adopted to demystify ‘business management’ and to encourage development of competency in business planning in the designated time. The success achieved so far indicates that leadership-based project management is a powerful approach to achieving accelerated cultural changes and transformation of human mindsets in a pluralistic and focused manner.     

Games People Play with Cost Control in Australia

A study of a selected group of building and engineering construction contractors in the Australian construction industry was performed in order to determine the actual site cost control procedures and techniques being practiced. The study was conducted through a detailed questionnaire completed by the researcher during the course of interview sessions with the site managers of the 18 construction projects in the sample. The main trends disclosed from the questionnaire allowed a model of actual site cost control procedures to be flowcharted. This system was then subjected to a comparative analysis with an idealized site cost control system developed in a previous study. Cost control functions that are discussed in this paper include, among others, the method of work breakdown for site use in cost control, performance data feedback techniques and uses, yardsticks for cost control, and management action at the site. The study concludes with a set of general recommendations aimed to bring current site cost control practices more in line with the available body of knowledge.     

Probabilistic unit cost estimation for project configuration optimization

A probabilistic approach to unit cost estimation and project configuration optimization has been developed and explained. A worked example included is intended to illustrate the pitfalls of relying excessively on deterministic cost appraisal.