Study on the preparation and properties of novel block copolymeric materials based on structurally modified organometallic as well as organic polyamides and polydimethylsiloxane

Some novel ferrocene‐containing polyamide‐based block copolymer materials with telechelic polydimethylsiloxane oligomer and their organic analogues were prepared by solution‐phase polycondensation of ferrocene‐based organometallic and terephthaloyl‐ as well as isophthaloyl‐based organic acyl chlorides with a series of semi‐aromatic diamines having ether linkages together with variable aliphatic character. The corresponding polyamides of the synthesized materials, without polydimethylsiloxane segment, were also prepared for comparison of physicochemical properties. None of the synthesized organometallic and organic block copolymers along with their respective polyamides melted below 300 °C and their structural features were confirmed by their physical properties and spectroscopic studies. The weight‐average molecular weights and molecular parameters of all these materials were determined by the static laser light scattering technique. The materials were soluble in sulfuric acid and partially soluble in common organic solvents, and yet became readily soluble upon N‐trifluoroacetylation. The synthesized materials were further characterized by their water absorption characteristics, X‐ray diffraction studies and surface morphology (SEM and AFM) and thermal (DSC and TG) analyses, and their structure–property relationships were elucidated from these studies. The energies of pyrolysis for these materials were calculated by the Horowitz and Metzger method. © 2012 Society of Chemical Industry     

Short- and long-term effects of fraternity and sorority membership on heavy drinking: A social norms perspective.

This study sought to determine whether the well-established relation between fraternity/sorority (Greek) membership and heavy alcohol use persists beyond the college years and whether some common third variables might account for the relation between Greek status and heavy drinking. During each of 4 years of college and 1 additional year, young adults (N ?=?319) completed measures of alcohol use, personality, alcohol expectancies, and environmental influences on drinking. Throughout the college years, Greeks consistently drank more heavily than non-Greeks. Statistically controlling for previous alcohol use did not eliminate this effect. However, Greek status did not predict postcollege heavy drinking levels. Also, perceived peer norms for heavy drinking mediated the relation between Greek affiliation and heavy alcohol use. Results are discussed in terms of situational determinants of heavy alcohol involvement in young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of radially varying magnetic field on a peristaltic flow of non‐Newtonian fluid in the presence of heat and mass transfer

This article deals with the variable MHD effects on the peristaltic flow of a non‐Newtonian fluid in the presence of heat and mass transfer. The walls of annulus are maintained at different temperatures. Continuity, momentum concentration, and energy equations are utilized in the mathematical analysis. Two types of solutions, namely, the exact and numerical, are derived. These solutions are compared and discussed. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20314     

Communication patterns and response to treatment among depressed and nondepressed maritally distressed couples.

Compared 35 maritally distressed couples assigned to 1 of 3 cognitive behavioral marital therapy (BMT) groups. Groups represented (1) couples in which 1 spouse was depressed at pretest, (2) couples in which 1 spouse showed psychopathology other than depression, and (3) couples who showed no symptoms of individual psychopathology. Ss were administered, pre- and posttreatment, the Dyadic Adjustment Scale and the Minnesota Multiphasic Personality Inventory (MMPI). Pretreatment couples in Group 1 were the oldest and the least maritally satisfied, and expressed the most negative communication. 12 wks of BMT was an effective treatment modality for all groups when compared with a group of 12 couples on a wait list. BMT significantly increased marital adjustment for all 3 treatment groups and decreased the rates of negative communication. BMT significantly decreased the level of depression in Group 1 and the level of psychopathology in Group 2. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Purification,surface modification of coal ash silica and its potential application in rubber composites

This article reports the purification and surface modification of coal ash silica and afterwards its utilization as reinforcing filler in solution‐styrene‐butadiene rubber/butadiene rubber (S‐SBR/BR). The coal ash silica free of unwanted metal ions/mineral oxides was obtained using phosphoric acid. The chemical composition of the purified coal ash silica in comparison to impure coal ash indicates the presence of characteristic hydroxyl functional group at 3440 cm^?1 and an increase in the oxygen content as determined with the help of Fourier Transform Infrared and x‐ray photoelectron spectroscopy, respectively. The contact angle analysis shows that after purification the polar part of the surface energy increased to 17.5 from 12 m Jm^?2. While the surface area increased to an order of magnitude, i.e., 11.6 to 110.5 m² g^?1. The modification of purified silica particles with bis(3‐triethoxysilylpropyl) tetrasulfane reveal the functionalization of hydroxyl to ‐Si‐O‐R groups as detected at 1560 cm^?1. As a consequence, the modified silica based S‐SBR/BR composite resulted in improved mechanical properties due to enhanced silica‐rubber interaction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Breakage probability of irregularly shaped particles

The investigation of breakage probability by compression of single particles was carried out. The spherical glass particles and irregularly shaped particles of NaCl, sugar, basalt and marble were subjected to a breakage test. The breakage test includes the compression up to breakage of 100 particles to obtain the distribution of the breakage probability depending on the breakage force or compression work. The breakage test was conducted for five particle size fractions from each individual material, at two stressing rates. Thus obtained 50 breakage force distributions and corresponding 50 breakage work distributions were fitted with log-normal distribution function.Usually, the breakage probability distribution can be found by means of stress or energy approach. The first one uses the stress to calculate the breakage probability distribution. The second approach uses the mass-related work done to break the particle. We prefer to use the breakage force and energy as essential variables. The correlation between the force and energy at their breakage points is obtained by integrating the characteristic force–displacement curve, i.e. the constitutive function of elastic–plastic mechanical behavior of the particle. The irregularly shaped particle is approximated by comparatively “large” hemispherical asperities. In terms of elastic–plastic deformation of the contacting asperities with the plate, a transition from elastic to inelastic deformation behavior was considered. Thus, one may apply the model of soft contact behavior of comparatively stiff hemispheres. Based on this model a relationship between the breakage force distributions and corresponding energy distributions was analyzed. Every tested material exhibits a linear relationship between average breakage energy and average breakage force calculated for every size fraction.For future consideration both force and energy distributions were normalized by division by average force or energy, consequently. The relationship between the fit parameters of normalized energy distribution and corresponding fit parameters of normalized force distribution was established. The mean value and standard deviation of normalized force distribution can be found from mean value and standard deviation of normalized energy distribution by means of system of two linear equations. The coefficients of those linear equations remain the same for all of the above tested materials; particle size fractions and stressing rates. As a result the simple transformation algorithm of distributions is developed. According to this algorithm the force distribution can be transformed into energy distribution and vice versa.     

Morpho-anatomical characterization of some members of euglenophycota (algae) of north-east Punjab,Pakistan based on light microscopy (LM) and scanning electron microscopy (SEM)

The study was carried out in four districts, that is, Gujranwala, Gujarat, Narowal and Sialkot of Punjab, Pakistan. The sampling was carried out randomly in different seasons from the water bodies especially from wastewater. Twenty-one species belonging to Euglenophycota were identified using light microscopy and scanning electron microscopy from which 04 species belong to genus Phacus, 02 species belonging to Trachelomonas and Euglena based on light microscopy. It was observed that Euglena was the most diverse genus and it is supposed to be the indicator species of the polluted water. It was observed that E. oblonga was found in maximum pH range, that is, 7.0–11.0. Similarly, E. brevicaudatus was found in maximum EC, that is, 169 ± 1.5 ms/cm these outcomes indicated that for internal examination along with LM, SEM was necessary for correct identification of algal sample up to specie level.     

Pollen morphology and its taxonomic potential in some selected taxa of Caesalpiniaceae observed under light microscopy and scanning electron microscopy

Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.     

Palyno-anatomical characters and their systematic significance in the family Apiaceae from Chitral,eastern Hindu Kush,Pakistan

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 μm and equatorial diameter of 21.6 μm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 μm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 μm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 μm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 μm and abaxial 50.25 × 39.40 μm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.