Stress cracking and photodegradation behavior of polycarbonate. The combination of two major causes of polymer failure

This work investigates the effects of photodegradation on the environmental stress cracking resistance of polycarbonate (PC). Injection molded samples were exposed to the ultraviolet (UV) light for various times in the laboratory prior to solvent contact. The bars were then stressed with two different loads in a tensile testing machine under the presence of ethanol. During this period, the stress relaxation was monitored and, after unloading, the ultimate properties were evaluated. Complementary tests were done by size exclusion chromatography, UV-visible spectroscopy, scanning electron microscopy, and light microscopy. The results indicated that ethanol causes significant modification in PC, with extensive surface crazing as well as reduction in mechanical properties. The previous degraded samples showed a higher level of stress relaxation and a greater loss in tensile strength in comparison with the undegraded ones. The synergist action of photodegradation and stress cracking in PC may be a consequence of the chemical changes caused by oxidation.

Spatio-temporal variability behavior of land surface soil water content in shrub- and grass-land

The knowledge of the relationship between spatial variability of the surface soil water content (theta) and its mean across a spatial domain (theta(m)) is crucial for hydrological modeling and understanding soil water dynamics at different scales. With the aim to compare the soil moisture dynamics and variability between the two land uses and to explore the relationship between the spatial variability of theta and theta(m), this study analyzed sets of surface theta measurements performed with an impedance soil moisture probe, collected 136 times during a period of one year in two transects covering different land uses, i.e., korshinsk peashrub transect (KPT) and bunge needlegrass transect (BNT), in a watershed of the Loess Plateau, China. Results showed that the temporal pattern of theta behaved similarly for the two land uses, with both relative wetter soils during wet period and relative drier soils during dry period recognized in BNT. Soil moisture tended to be temporally stable among different dates, and more stable patterns could be observed for dates with more similar soil water conditions. The magnitude of the spatial variation of theta in KPT was greater than that in ENT. For both land uses, the standard deviation (SD) of theta in general increased as theta(m) increased, a behavior that could be well described with a natural logarithmic function. Convex relationship of CV and theta(m) and the maximum CV for both land uses (43.5% in KPT and 41.0% in BNT) can, therefore, be ascertained. Geostatistical analysis showed that the range in KPT (9.1 m) was shorter than that in BNT (15.1 m). The nugget effects, the structured variability, hence the total variability increased as theta(m) increased. For both land uses, the spatial dependency in general increased with increasing theta(m). 2011 Elsevier B.V. All rights reserved.

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Ines lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

The dynamic of shrinkage/moisture content behavior determined during drying of microsamples for different kinds of wood

This article presents the results obtained from an experimental device designed for the accurate determination of wood/water relationship on microsamples. The moisture content of the sample is measured with a highly sensitive electronic microbalance and two dimensions of the sample are collected continuously without contact using high-speed laser scan micrometers. The whole device is placed in a climatic chamber. The microsamples investigated were prepared with a diamond wire saw. The unique ability of this device to work with small samples allowed normal, opposite, and reaction wood to be characterized separately. Experiments were carried out on three wood species (beech, spruce, and poplar). In the case of beech, a deviation from the linear relation between tangential shrinkage and moisture content between 40 and 20% is particularly noticeable for the first desorption. A localized collapse of ray cells could explain this result. Compared to normal wood, an important longitudinal shrinkage and a low tangential shrinkage were observed in compression wood of spruce. Both the tension wood and opposite wood of poplar exhibit a high longitudinal shrinkage, but no significant difference between the three types of wood is noticeable in the tangential direction.

Influence of chemical interesterification on thermal behavior, microstructure, polymorphism and crystallization properties of canola oil and fully hydrogenated cottonseed oil blends

This work evaluated chemical interesterification of canola oil (CaO) and fully hydrogenated cottonseed oil (FHCSO) blends, with 20%, 25%, 30%, 35% and 40%(w/w) FHCSO content. Interesterification produced reduction of trisaturated and increase in monounsaturated and diunsaturated triacylglycerols contents, which caused important changes in temperatures and enthalpies associated with the crystallization and melting thermograms. It was verified reduction in medium crystal diameter in all blends, in addition crystal morphology modification. Crystallization kinetics revealed that crystal formation induction period and maximum solid fat content were altered according to FHCSO content in original blends and as a result of random rearrangement. Changes in Avrami constant (k) and exponent (n) indicated, respectively, that interesterification decreased crystallization rates and altered crystalline morphology. However, X-ray diffraction analyses showed randomization did not change the original crystalline polymorphism. The original and interesterified blends had significant predominance of beta` polymorph, which is interesting for several food applications. (C) 2009 Elsevier Ltd. All rights reserved.

Thermal Behavior, Microstructure, Polymorphism, and Crystallization Properties of Zero Trans Fats from Soybean Oil and Fully Hydrogenated Soybean Oil

Blends of soybean oil (SO) and fully hydrogenated soybean oil (FHSBO), with 10, 20, 30, 40, and 50% (w/w) FHSBO content were interesterified under the following conditions: 20 min reaction time, 0.4% sodium methoxide catalyst, and 500 rpm stirring speed, at 100 A degrees C. The original and interesterified blends were examined for triacylglycerol composition, thermal behavior, microstructure, crystallization kinetics, and polymorphism. Interesterification produced substantial rearrangement of the triacylglycerol species in all the blends, reduction of trisaturated triacylglycerol content and increase in monounsaturated-disaturated and diunsaturated-monosaturated triacylglycerols. Evaluation of thermal behavior parameters showed linear relations with FHSBO content in the original blends. Blend melting and crystallization thermograms were significantly modified by the randomization. Interesterification caused significant reductions in maximum crystal diameter in all blends, in addition to modifying crystal morphology. Characterization of crystallization kinetics revealed that crystal formation induction period (tau (SFC)) and maximum solid fat content (SFC(max)) were altered according to FHSBO content in the original blends and as a result of the random rearrangement. Changes in Avrami constant (k) and exponent (n) indicated, respectively, that-as compared with the original blends-interesterification decreased crystallization velocities and modified crystallization processes, altering crystalline morphology and nucleation mechanism. X-ray diffraction analyses revealed that interesterification altered crystalline polymorphism. The interesterified blends showed a predominance of the beta` polymorph, which is of more interest for food applications.

The behavior of key enzymes of xylose metabolism on the xylitol production by Candida guilliermondii grown in hemicellulosic hydrolysate

A variety of raw materials have been used in fermentation process. This study shows the use of rice straw hemicellulosic hydrolysate, as the only source of nutrient, to produce high added-value products. In the present work, the activity of the enzymes xylose reductase (XR); xylitol dehydrogenase (XD); and glucose-6-phosphate dehydrogenase (G6PD) during cultivation of Candida guilliermondii on rice straw hemicellulosic hydrolysate was measured and correlated with xylitol production under different pH values (around 4.5 and 7.5) and initial xylose concentration (around 30 and 70 g l(-1)). Independent of the pH value and xylose concentration evaluated, the title of XD remained constant. On the other hand, the volumetric activity of G6PD increased whereas the level of XR decreased when the initial xylose concentration was increased from 30 to 70 g l(-1). The highest values of xylitol productivity (Q (P) a parts per thousand 0.40 g l(-1)) and yield factor (Y (P/S) a parts per thousand 0.60 g g(-1)) were reached at highest G6PD/XR ratio and lowest XR/XD ratio. These results suggest that NADPH concentrations influence the formation of xylitol more than the activity ratios of the enzymes XR and XD. Thus, an optimal rate between G6PD and XR must be reached in order to optimize the xylitol production.

Rheological behavior, zeta potential, and accelerated stability tests of Buriti oil (Mauritia flexuosa) emulsions containing lyotropic liquid crystals

Background: It is well known that the Amazon region presents a huge biodiversity; therefore, countless natural resources are being employed in the production of phytocosmetics and phytomedicines. Objective: The purpose of this work was to obtain emulsions produced with Buriti oil and nonionic surfactants. Methods: Two surfactant systems were employed (Steareth-2 associated to Ceteareth-5 and to Ceteareth-20) to produce the emulsions using phase diagram method. Emulsions were obtained by echo-planar imaging method at 75 degrees C. Rheological behavior and zeta potential were evaluated, and accelerated stability tests were performed. Results: All emulsions analyzed presented pseudoplastic behavior. Zeta potential values were obtained between -14.2 and -53.3 mV. The formulations did not show changes in either physical stability, pH, or rheological behavior after accelerated stability tests. Significant differences were observed only after temperature cycling test. Conclusion: Based on these results, the emulsions obtained could be considered as promising delivery systems.

Rumors of the death of emotional intelligence in organizational behavior are vastly exaggerated

In the first of two articles presenting the case for emotional intelligence in a point/counterpoint exchange, we present a brief summary of research in the field, and rebut arguments against the construct presented in this issue.We identify three streams of research: (1) a four-branch abilities test based on the model of emotional intelligence defined in Mayer and Salovey (1997); (2) self-report instruments based on the Mayer–Salovey model; and (3) commercially available tests that go beyond the Mayer–Salovey definition. In response to the criticisms of the construct, we argue that the protagonists have not distinguished adequately between the streams, and have inappropriately characterized emotional intelligence as a variant of social intelligence. More significantly, two of the critical authors assert incorrectly that emotional intelligence research is driven by a utopian political agenda, rather than scientific interest. We argue, on the contrary, that emotional intelligence research is grounded in recent scientific advances in the study of emotion; specifically regarding the role emotion plays in organizational behavior. We conclude that emotional intelligence is attracting deserved continuing research interest as an individual difference variable in organizational behavior related to the way members perceive, understand, and manage their emotions.

The case for the ability-based model of emotional intelligence in organizational behavior

In this second counterpoint article, we refute the claims of Landy, Locke, and Conte, and make the more specific case for our perspective, which is that ability-based models of emotional intelligence have value to add in the domain of organizational psychology. In this article, we address remaining issues, such as general concerns about the tenor and tone of the debates on this topic, a tendency for detractors to collapse across emotional intelligence models when reviewing the evidence and making judgments, and subsequent penchant to thereby discount all models, including the ability-based one, as lacking validity. We specifically refute the following three claims from our critics with the most recent empirically based evidence: (1) emotional intelligence is dominated by opportunistic academics-turned-consultants who have amassed much fame and fortune based on a concept that is shabby science at best; (2) the measurement of emotional intelligence is grounded in unstable, psychometrically flawed instruments, which have not demonstrated appropriate discriminant and predictive validity to warrant/justify their use; and (3) there is weak empirical evidence that emotional intelligence is related to anything of importance in organizations. We thus end with an overview of the empirical evidence supporting the role of emotional intelligence in organizational and social behavior.

Diversity and Emotion: The New Frontiers in Organizational Behavior Research

This article provides a review of recent developments in two topical areas of research in contemporary organizational behavior: diversity and emotions. In the section called “Diversity,”we trace the history of diversity research, explore the definitions and paradigms used in treatments of diversity, and signal new areas of interest. We conclude that organizational behavior in the 21st century is evolving to embrace a more eclectic and holistic view of humans at work. In the section called “Emotions,” we turn our attention to recent developments in the study of emotions in organizations. We identify four major topics: mood theory, emotional labor, affective events theory (AET), and emotional intelligence, and argue that developments in the four domains have significant implications for organizational research, and the progression of the study of organizational behavior. As with the study of diversity, the topic of emotions in the workplace is shaping up as one of the principal areas of development in management thought and practice for the next decade. Finally, we discuss in our conclusion how these two areas are being conceptually integrated, and the implications for management scholarship and research in the contemporary world.

Prevention of child behavior problems through universal implementation of a group behavioral family intervention.

The aim of this mental health promotion initiative was to evaluate the effectiveness of a universally delivered group behavioral family intervention (BFI) in preventing behavior problems in children. This study investigates the transferability of an efficacious clinical program to a universal prevention intervention delivered through child and community health services targeting parents of preschoolers within a metropolitan health region. A quasiexperimental two-group (BFI, n=804 vs. Comparison group, n=806) longitudinal design followed preschool aged children and their parents over a 2-year period. BFI was associated with significant reductions in parent-reported levels of dysfunctional parenting and parent-reported levels of child behavior problems. Effect sizes on child behavior problems ranged from large (.83) to moderate (.47). Positive and significant effects were also observed in parent mental health, marital adjustment, and levels of child rearing conflict. Findings are discussed with respect to their implication for significant population reductions in child behavior problems as well as the pragmatic challenges for prevention science in encouraging both the evaluation and uptake of preventive initiatives in real world settings.

Reducing problem behavior during care-giving in families of preschool-aged children with developmental disabilities

This study evaluated two variants of a behavioral parent training program known as Stepping Stones Triple P (SSTP) using 74 preschool-aged children with developmental disabilities. Families were randomly allocated to an enhanced parent training intervention that combined parenting skills and care-giving coping skills (SSTP-E), standard parent training intervention alone (SSTP-S) or waitlist control (WL) condition. At post-intervention, both programs were associated with lower levels of observed negative child behavior, reductions in the number of care-giving settings where children displayed problem behavior, and improved parental competence and satisfaction in the parenting role as compared with the waitlist condition. Gains attained at post-intervention were maintained at 1-year follow-up. Both interventions produced significant reductions in child problem behavior, with 67% of children in the SSTP-E and 77% of children in the SSTPS showing clinically reliable change from pre-intervention to follow-up. Parents reported a high level of satisfaction with both interventions.

Perceptions of a media campaign: The role of social identity and the changing intergroup context

This study examined the effects of political identity and the changing intergroup context on communication perceptions during an election campaign. Perceptions of media bias and of campaign impact on self and others were assessed before and after the election. The responses of politically aligned voters reflected their membership in a dominant or subordinate group preelection and in a losing or winning group postelection. Dominant group members were initially less biased in their views of the campaign and its impact but sought to blame their party's loss on media bias and on the gullibility of political out-group members and voters in general. Subordinate group members initially showed strong in-group-serving biases but were less critical of the media and the electorate after their party had won. Results highlight the dynamic, intergroup, nature of media perceptions.