Senior managers’ perception on green information systems (IS) adoption and environmental performance: Results from a field survey

Based on a Belief-Action-Outcome framework, we produced a model that shows senior managers’ perception of both the antecedents to and the consequences of Green IS adoption by a firm. This conceptual model and its associated hypotheses were empirically tested using a dataset generated from a survey of 405 organizations. The results suggest that coercive pressure influences the attitude toward Green IS adoption while mimetic pressure does not. In addition, we found that there was a significant relationship between Green IS adoption, attitude, and consideration of future consequences. Finally, we found that only long term Green IS adoption was positively related to environmental performance.     

Effectiveness of different surface cleaning methods on the shear bond strength of resin cement to contaminated zirconia: an in vitro study

The purpose of this in vitro study was to evaluate and compare the effectiveness of different surface cleaning methods on the shear bond strength (SBS) of zirconia ceramic surfaces. Seventy polished and cleaned zirconia disk specimens of 8 mm in diameter and 3.4 mm in thickness were immersed in fresh saliva. They were then pressed into a freshly mixed silicone disclosing medium. Six different cleaning methods were applied to the tested groups; they were airborne-particle abraded (AA), covered with a cleaning paste (Ivoclean®) (IV), etched with orthophosphoric acid (PA), immersed in alcohol (AL), rinsed with tap water only (WA), or cleaned with steam (SC). No surface cleaning was done after saliva immersion and silicone disclosing medium contamination to the control group (CC). The specimens were then bonded to an adhesive resin cement using polyethylene tubes. SBS was determined using a universal testing machine at a crosshead speed of 1 mm/min. The specimens were also examined with a scanning electron microscope and a stereomicroscope. Group AA yielded the highest SBS value (7.01 ± 1.4 MPa) among the groups, while Group WA had the lowest SBS value (3.03 ± 0.8 MPa). The SBS values of Group AA (7.01 ± 1.4 MPa) and IV (6.2 ± 1.7 MPa) were also significantly higher than those of the remaining four groups (p < 0.05). Within the limitations of this in vitro study, it was concluded that among the various cleaning methods tested, airborne-particle abrasion and Ivoclean® paste were effective in cleaning the zirconia surface.     

Synthesis and characterization of a novel pH-responsive nanocomposite hydrogel based on chitosan for targeted drug release

Over the last decade, nanocomposite hydrogels have been provided a new approach for the biomedical field. In this work, a novel pH-responsive nanocomposite hydrogel was fabricated using simultaneous in situ formation of magnetite iron oxide nanoparticles and hydrogel networks of poly(acrylic acid) grafted onto chitosan. The effects of various types of precursor molecules, pH, salt, and loading pressure were examined on the swelling properties of resulting nanocomposite hydrogels. The synthesized nanocomposite hydrogel was well characterized using different instruments. In vitro drug releasing behavior of doxorubicin was studied at pH 5.4 and 7.4. The drug release mechanism was investigated through different kinetic models. These experimental results open a new opportunity to make pH-responsive nanocomposite hydrogel devices for controlled delivery of drug.     

Formation of 3D networks in polylactic acid by adjusting the cross-linking agent content with respect to processing variables: a simple approach

High-performance biodegradable polymers have attracted considerable attention over the years because of their eco-friendly nature. The effects of processing variables on the efficiency of crosslinking, and the rheological and thermal properties of cross-linked polylactic acid (XPLA) have not been comprehensively addressed yet. In this work, XPLA was prepared through solution casting followed by curing in an oven. Enhancements in properties could be quantified in terms of structural changes in 3D structure of XPLA by varying the amount of dicumyl peroxide (DCP) as a cross--linking agent and curing temperature and time. The XPLAs were characterized by differential scanning calorimetry, thermo-gravimetric analysis, swelling, and rheological techniques. The swelling data revealed an increase in gel fraction by 1.32% per 1 °C temperature rise in the range of 125–195 °C. The results were also indicative of an increase in gel faction by 0.32% per minute in the time range of 5–100 min. Maximum variation in gel fraction occurred at 195 °C with high peroxide content. At this temperature, the variation rate of gel content was about 14.99%. With gel formation evolution, especially at 85% completion stage, the melting point was vanished. Rheological measurements showed that the Newtonian plateau disappeared for the cross-linked samples, simultaneously with the onset of shear thinning and zero-shear viscosity, through which the molecular weight obtained by the Mark–Houwink equation shifted to lower frequencies. A mathematical model based on the Charlesby–Pinner equation was developed for predicting the gel content of the XPLA as a function of curing time and peroxide concentration. The Flory–Huggins parameter also changed during the cross-linking process as a function of cross-linking density. This study is focused on adjusting cross-linking density and processing factors, like temperature and time, to achieve an XPLA with desirable properties.     

Removal of toxic nitrate ions from drinking water using conducting polymer/MWCNTs nanocomposites

New application of conducting polymers as stable nanocomposites for nitrate ion exchange materials in water and wastewater treatment and for environmental protection is introduced in this work. The nanocomposites of multi-walled carbon nanotubes (MWCNTs) with different polymers such as: polyaniline (PANI), polypyrrole (PPY), poly(1,8-diaminonaphthalene) [P(1,8-DAN)] and poly(2-vinylpyridine) (P2VP) were synthesized with different dopants as effective and reusable nanocomposites for nitrate removal from drinking water. Nitrate anions at toxic concentrations were removed from water using ion exchange mechanism without any toxic byproducts. The obtained results demonstrate that effective ion exchange occurs between NO₃ ^? and Cl^?. There are some protonated heteroatoms in polymer chains that are bonded with anions of dopants and their counter ions in nanocomposites. These dopant anions on the =NH⁺– groups of polymers can be exchanged with NO₃ ^? in water. Adsorption of NO₃ ^? on polymer/MWCNTs nanocomposites showed dependency to some parameters. Different experimental parameters such as pH and temperature of the sample, polymers dopant, and the ratio of polymer to MWCNTs in nanocomposites affect the amount of nitrate removal. The highest removal efficiency was achieved at 1.20 g L^?1 of PANI/MWCNTs (3:1) nanocomposite, pH = 6.5 and ambient temperature. After five successive cycles of nitrate removal, this parameter was still up to 70 % compared to the first run (up to 80 %).     

MOSFET栅氧泄漏隧穿电流的分析模型:量子力学研究(英文)

研发了一种通过MOSFET的超薄栅氧化物分析直接隧穿电流密度的模型。采用Wentzel-Kramers-Brilliouin(WKB)近似计算了隧穿概率,利用清晰的表面势方程改进模型的准确性。在研究模型中考虑了Si衬底中反型层的量子化和多晶硅栅耗尽,还研究了多晶硅掺杂对栅氧化层隧穿电流的影响。仿真结果表明,栅氧化层隧穿电流随多晶硅栅掺杂浓度的增加而增加。该结论与已报道的结果相吻合,从而证明了该模型的正确性。     

Oligodeoxyribonucleotide association with single-walled carbon nanotubes studied by SPM

Studies have been performed on both as-received and chemically oxidized single-walled carbon nanotubes (SWCNTs) grown by two different growth methods to better understand the preferential association of the oligodeoxyribonucleotide T30 (ODN) with SWCNTs. Samples of T30 ODN:SWCNT were examined under ambient conditions using non-contact scanning probe microscope (SPM) techniques. The resulting images show different morphologies ranging from tangled networks of SWCNTs to individual, well-dispersed isolated SWCNTs as the sonication time is increased. SPM images of well-dispersed, as-received SWCNTs reveal isolated features that are 1.4 to 2.8 nm higher than the bare SWCNT itself. X-ray photoemission spectroscopy (XPS) confirmed these features to be T30 ODN in nature. Chemically oxidizing the SWCNTs before sonication is found to be an effective way to increase the number of T30 ODN features.