The Reactivity of Dissolved Organic Matter for Disinfection By-Product Formation

Dissolved organic matter (DOM) in 6 water samples collected from 4 surface waters were fractionated using some or all of 5 physicochemical separation processes (activated carbon and XAD-8 batch adsorption, alum coagulation, ultrafiltration (UF), and XAD-8 column fractionation). Activated carbon, XAD-8 batch adsorption and alum coagulation processes fractionated DOM by preferentially removing high-SUVA components from solution. The XAD-8 column method fractionated DOM into hydrophobic and hydrophilic components while UF separated DOM into different size fractions. Over 40 DOM fractions, characterized using carbon-normalized (specific) ultraviolet absorbance (SUVA), were obtained for each water. Trihalomethane (THM) and haloacetic acid (HAA_9) formation after chlorination was quantified for each fraction. For each natural water, a strong correlation was observed between the SUVA values of DOM fractions and their THM and HAA_9 formations, independent of the separation processes used to obtain the fractions. Therefore, the correlation obtained for each water appears to represent its natural disinfection by-product (DBP) reactivity profile. However, SUVA is not a universal predictor of DOM reactivity because a unique DBP reactivity profile was obtained for each water tested. The distribution of SUVA within a source water and its relationship to reactivity were found to be more informative than the source water aggregate SUVA value. Individual DBP species also correlated well with the SUVA of DOM fractions in a single water. Formation of trichloroacetic acid (TCAA) was dominant over dichloroacetic acid (DCAA) for high-SUVA fractions, whereas the formation of TCAA and DCAA was comparable for low-SUVA fractions

The effect of plasma functionalization on the print performance and time stability of graphite nanoplatelet electrically conducting inks

Carbon-based pastes and inks are used extensively in a wide range of printed electronics because of their widespread availability, electrical conductivity and low cost. Overcoming the inherent tendency of the nano-carbon to agglomerate to form a stable dispersion is necessary if these inks are to be taken from the lab scale to industrial production. Plasma functionalization of graphite nanoplatelets (GNP) adds functional groups to their surface to improve their interaction with the polymer resin. This offers an attractive method to overcome these problems when creating next generation inks. Both dynamic and oscillatory rheology were used to evaluate the stability of inks made with different loadings of functionalized and unfunctionalized GNP in a thin resin, typical of a production ink. The rheology and the printability tests showed the same level of dispersion and electrical performance had been achieved with both functionalized and unfunctionalized GNPs. The unfunctionalized GNPs agglomerate to form larger, lower aspect particles, reducing interparticle interactions and particle–medium interactions. Over a 12-week period, the viscosity, shear thinning behavior and viscoelastic properties of the unfunctionalized GNP inks fell, with decreases in viscosity at 1.17 s−1 of 24, 30, 39% for the ϕ = 0.071, 0.098, 0.127 GNP suspensions, respectively. However, the rheological properties of the functionalized GNP suspensions remained stable as the GNPs interacted better with the polymer in the resin to create a steric barrier which prevented the GNPs from approaching close enough for van der Waals forces to be effective

Stretchable Carbon and Silver Inks for Wearable Applications

For wearable electronic devices to be fully integrated into garments, without restricting or impeding movement, requires flexible and stretchable inks and coatings, which must have consistent performance and recover from mechanical strain. Combining Carbon Black (CB) and ammonia plasma functionalized Graphite Nanoplatelets (GNPs) in a Thermoplastic Polyurethane (TPU) resin created a conductive ink that could stretch to substrate failure (>300% nominal strain) and cyclic strains of up to 100% while maintaining an electrical network. This highly stretchable, conductive screen-printable ink was developed using relatively low-cost carbon materials and scalable processes making it a candidate for future wearable developments. The electromechanical performance of the carbon ink for wearable technology is compared to a screen-printable silver as a control. After initial plastic deformation and the alignment of the nano carbons in the matrix, the electrical performance was consistent under cycling to 100% nominal strain. Although the GNP flakes are pulled further apart a consistent, but less conductive path remains through the CB/TPU matrix. In contrast to the nano carbon ink, a more conductive ink made using silver flakes lost conductivity at 166% nominal strain falling short of the substrate failure strain. This was attributed to the failure of direct contact between the silver flakes

Rheology of high-aspect-ratio nanocarbons dispersed in a low-viscosity fluid

Printing inks typically consist of a functional component dispersed within a low-viscosity resin/solvent system where interparticle interactions would be expected to play a significant role in dispersion, especially for the high-aspect-ratio nanocarbons such as the graphite nanoplatelets (GNPs). Rheology has been suggested as a method for assessing the dispersion of carbon nanomaterials in a fluid. The effects of phase volume of ammonia plasma-functionalized GNPs on a near-Newtonian low-viscosity thermoplastic polyurethane (TPU) resin system have been studied using shear and quiescent oscillatory rheology. At low concentrations, the GNPs were well dispersed with a similar shear profile and viscoelastic behavior to the unfilled TPU resin, as viscous behavior prevailed indicating the absence of any long-range order within the fluid. Particle interactions increased rapidly as the phase volume tended toward maximum packing fraction, producing rapid increases in the relative viscosity, increased low shear rate shear thinning, and the elastic response becoming increasingly frequency independent. The nanoscale dimensions and high-aspect-ratio GNPs occupied a large volume within the flow, while small interparticle distances caused rapid increases in the particle–particle interactions to form flocculates that pack less effectively. Established rheological models were fitted to the experimental data to model the effect of high-aspect-ratio nanocarbon on the viscosity of a low-viscosity system. Using the intrinsic viscosity and the maximum packing fraction as fitting parameters, the Krieger–Dougherty (K–D) model provided the best fit with values. There was good agreement between the estimates of aspect ratio from the SEM images and the predictions of the aspect ratio from the rheological models. The fitting of the K–D model to measured viscosities at various phase volumes could be an effective method in characterizing the shape and dispersion of high-aspect-ratio nanocarbons

Whatever it takes: rivalry and unethical behavior

This research investigates the link between rivalry and unethical behavior. We propose that people will engage in greater unethical behavior when competing against their rivals than when competing against non-rival competitors. Across a series of experiments and an archival study, we find that rivalry is associated with increased use of deception, unsportsmanlike behavior, willingness to employ unethical negotiation tactics, and misreporting of performance. We also explore the psychological underpinnings of rivalry, which help to illuminate how it differs from general competition, and why it increases unethical behavior. Rivalry as compared to non-rival competition was associated with increased status concerns, contingency of self-worth, and performance goals; mediation analyses revealed that performance goals played the biggest role in explaining why rivalry promoted greater unethicality. Lastly, we find that merely thinking about a rival can be enough to promote greater unethical behavior, even in domains unrelated to the rivalry. These findings highlight the importance of rivalry as a widespread, powerful, yet largely unstudied phenomenon with significant organizational implications. Further, the results help to inform when and why unethical behavior occurs within organizations, and demonstrate that the effects of competition are dependent upon relationships and prior interactions

Printed Nanocarbon Heaters for Stretchable Sport and Leisure Garments

The ability to maintain body temperature has been shown to bring about improvementsin sporting performance. However, current solutions are limited with regards to flexibility, heatinguniformity and robustness. An innovative screen-printed Nanocarbon heater is demonstrated whichis robust to bending, folding, tensile extensions of up to 20% and machine washing. This combinationof ink and substrate enables the heated garments to safely flex without impeding the wearer. It iscapable of producing uniform heating over a 15 × 4 cm area using a conductive ink based on a blendof Graphite Nanoplatelets and Carbon Black. This can be attributed to the low roughness of theconductive carbon coating, the uniform distribution and good interconnection of the carbon particles.The heaters have a low thermal inertia, producing a rapid temperature response at low voltages,reaching equilibrium temperatures within 120 s of being switched on. The heaters reached the 40 ◦Crequired for wearable heating applications within 20 s at 12 Volts. Screen printing was demonstratedto be an effective method of controlling the printed layer thickness with good interlayer adhesionand contact for multiple printed layers. This can be used to regulate their electrical properties andhence adjust the heater performance

Impressing for Success: A Gendered Analysis of a Key Social Capital Accumulation Strategy

Social capital theory assesses the career benefits that accrue to individuals from the stock of relationships they have. Such benefits can be in the form of guidance and advice, access to key projects and assignments and help with setting up business deals. However, when assessing whether such career-enhancing resources are available equally to men and women, we find that gender impacts on the access to and accumulation of social capital. The article seeks to address two key research questions. The first is whether women are aware of the need to accumulate social capital to advance their careers and the second is whether they use impression management techniques in order to assist them in doing this. Findings are reported from a study in an international consulting firm with 19 female consultants. In respect of research question one the findings indicate that women in the sample are aware of the need to accumulate social capital to advance their careers; with particular emphasis being placed on the importance of gaining access to influential sponsors. In respect of research question two, the findings confirm that women in the sample do perceive the necessity to utilise impression management techniques to help them to accumulate social capital. This is done in a defensive way and is linked to ensuring that one is seen as ambitious, likable and available. It is argued that these are key organizational norms, and it is perceived that in order to accumulate social capital, women need to actively work to dispel the negative stereotypes that attach to them because of their gender. The article calls for greater recognition of the impact that masculine organizational cultures have on the career development of women, who not only have to perform at a high level but are also required to expend additional energy conforming to masculine organizational cultures they have had little say in creating

The Grizzly, March 25, 2010

27th Annual Airband Benefits Dignity House • Ursinus College Theater Presents The Elephant Man • Bank Robber Flees to Ursinus Campus Parking Lot • InterVarsity Group Travels to Camden Over Spring Break • Dangerous Risk to Multi-Tasking • Ursinus Field Hockey Intramurals are Open for Spring • UC Baseball Makes Best of Florida Trip • UC Alum Coaches Cornell to Sweet 16https://digitalcommons.ursinus.edu/grizzlynews/1809/thumbnail.jp