A division of the thermomechanical exergy into two components with very different economic values

The aim of this work is to provide a tool for approximation to the actual energy market value. As exergy represents the quality of energy, in the normal procedure for thermoeconomic optimizing of a given thermal system, the exergy of each stream is used as the basic quantity. The usual method evaluates the cost rates appearing in the cost rate balance in terms of the associated rates of exergy transfer and the corresponding unit costs. In this work, the thermomechanical exergy of each stream is divided into two components with very different qualities and hence with different unit costs. The higher quality component can be assigned the same unit cost as work whereas the lower quality component will usually be assigned a lower unit cost. Therefore, the cost rates of a system's input or output streams will be closer to actual economic values, especially in processes with major pressure variations. An example related to combined cycles is included.     

Oxidative rancidity in avocado purée as affected by α-tocopherol, sorbic acid and storage atmosphere

Avocado is nutritionally rich in many health-related components and a valuable energy source due to their high quality fat content. The aim of this work was to evaluate the lipid oxidation of refrigerated avocado purée as affected by the addition of α-tocopherol and/or sorbic acid with antioxidant and antimicrobial purposes, respectively. Hence, the formation of hydroperoxides and secondary oxidation products was studied throughout storage under different modified atmosphere packaging conditions. Addition of α-tocopherol clearly reduced rancidity of the lipid fraction. When the antioxidant was added, hydroperoxide formation was inhibited for a period of at least 12 weeks with little effect of the presence of sorbic acid and O₂ availability. On the contrary, absence of α-tocopherol in the product formulation preceded the production of secondary oxidative metabolites and a rapid saturation of the fatty acid chains. Sorbic acid was found to have a moderate prooxidant effect (p < 0.05). This detrimental influence on the lipid phase of avocado should be weighted up against the antimicrobial effect in order to evaluate its capability of extending the shelf life of avocado products.     

Risk and resiliency processes in ethnically diverse families in poverty.

Families living in poverty face numerous stressors that threaten the health and well-being of family members. This study examined the relationships among family-level poverty-related stress (PRS), individual-level coping with PRS, and a wide range of psychological symptoms in an ethnically diverse sample of 98 families (300 family members) living at or below 150% of the federal poverty line. Hierarchical linear model (HLM) analyses revealed that family PRS is robustly related to a wide range of psychological syndromes for family members of both genders, all ages, and all ethnic backgrounds. In addition, primary and secondary control coping were both found to serve as buffers of PRS for many syndromes. For several psychological syndromes, parents showed significantly higher levels of symptoms, but the link between PRS and symptoms was significantly stronger for children than for adults. Ethnicity was not a significant predictor in overall HLM models or follow-up analyses, suggesting that the broad construct of PRS and the theoretical model tested here apply across the 3 major ethnic groups included in this study. The findings suggest that family-based, coping-focused interventions have the potential to promote resiliency and break linkages in the pernicious cycle of family economic stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular dynamics simulation of fast dislocations in copper

Molecular dynamics simulations are used to describe the acceleration and motion of dissociated dislocations in copper to extreme velocities. Stationary dislocations are accelerated either by shear stress or by shear strain rates. Results indicate that dislocations can be accelerated into transonic and supersonic velocities. Stable dislocation motion is found in three distinguished regimes: (i) in a plateau of velocities close to 1.6 km s^?1 in the subsonic regime; (ii) in a narrow range of velocities around 2.6 km s^?1 in the first transonic regime; and (iii) in the second transonic regime with increasing velocities. For large velocities in the second transonic regime and in the supersonic regime, the shear stress is exceeded and dislocation motion is unstable as the crystal loses its mechanical stability. The stacking fault fluctuates around 35 Å in the subsonic regime, but subsequently declines with velocity to less than half the initial value in the second transonic regime. Both the decreasing stacking fault width and the plateau of velocities in the first transonic regime, indicating the existence of a radiation-free state, are in agreement with theoretical predictions.     

Analysis of average burst-assembly delay and applications in proportional service differentiation

In Optical Burst-Switched (OBS) networks, the limitation of optical buffering devices make it impractical to deploy conventional delay-based differentiation algorithms such as Active Queue Management, Weighted Fair Queuing, etc. Furthermore, only the delay that appears due to the burst-assembly process constitutes a variable quantity (all the other sources of delay are mostly fixed), it is then reasonable to make use of the burst-assembly algorithm to provide class-based delay differentiation. The aim of the following study is twofold: first it defines an average assembly delay metric, which represents the assembly delay experienced by a random arrival at the burst assembler of an edge OBS node; and second, this metric is used to define and configure a two-class burst-assembly policy, which gives preference to high-priority traffic over low-priority packet arrivals. The results show that, (1) tuning the parameters of the two-class assembly algorithm, the two classes of traffic exhibit different burst-assembly delay; and, (2) such parameters can be adjusted to provide a given differentiation ratio in the light of the proportional QoS differentiation approach proposed in the literature. A detailed analysis of the two-class assembly algorithm is given, along with an exhaustive set of experiments and numerical examples that validate the equations derived.     

Toward knowledge-rich data mining

This position paper proposes knowledge-rich data mining as a focus of research, and describes initial steps in pursuing it.     

Theory of Raman Scattering by Phonons in Germanium Nanostructures

Within the linear response theory, a local bond-polarization model based on the displacement–displacement Green’s function and the Born potential including central and non-central interatomic forces is used to investigate the Raman response and the phonon band structure of Ge nanostructures. In particular, a supercell model is employed, in which along the [001] direction empty-column pores and nanowires are constructed preserving the crystalline Ge atomic structure. An advantage of this model is the interconnection between Ge nanocrystals in porous Ge and then, all the phonon states are delocalized. The results of both porous Ge and nanowires show a shift of the highest-energy Raman peak toward lower frequencies with respect to the Raman response of bulk crystalline Ge. This fact could be related to the confinement of phonons and is in good agreement with the experimental data. Finally, a detailed discussion of the dynamical matrix is given in the appendix section.     

A methodology for predicting the severity of environmental impacts related to the construction process of residential buildings

This paper introduces a systematic approach for dealing with potential adverse environmental impacts at the pre-construction stage. The proposed methodology serves as an assessment tool for construction projects to measure the environmental performance of their construction activities. It also provides a consistent basis for comparisons and for future eco-labelling and environmental benchmarking among construction companies and construction sites. Within the methodological framework, nine categories of environmental aspects are proposed: atmospheric emissions; water emissions; waste generation; soil alteration; resource consumption; local issues; transport issues; effects on biodiversity; and incidents, accidents and potential emergency situations. The methodology includes 20 performance indicators developed with the help of a panel of experts. In order to avoid a typical shortcoming in environmental assessments methods, these environmental indicators, both direct and indirect, are always based on quantitative data available in the project documents. Significance limits for environmental aspects are also developed based on a statistical analysis of 55 new-start construction projects. Four case studies are provided to illustrate the practical use of the proposed methodology.     

Relational tools for working with mild-to-moderate couple violence: Patterns of unresolved conflict and pathways to resolution.

This article offers psychologists an insider’s view of couples’ experiences with partner violence. Eleven couples seen at a university-based family and marriage clinic provided data on escalation of violence; 10 provided data on de-escalation, with 8 common to both analyses. In the Patterns and Pathways intervention, the couples first detailed their patterns of unresolved conflict and described barriers that impeded their willingness to resolve their conflicts peacefully. The progressive stages of (a) First Signs of Conflict, (b) Stirring the Pot, and (c) Point of No Return repeat themselves if couples fail to find alternative routes to conflict resolution. In the intervention’s Pathways phase, the couples examined their strategies for interrupting these sequences and created nonviolent pathways to constructive resolution, which included (a) taking responsibility for self, (b) demonstrating respect for one’s partner, and (c) making efforts to improve communication. Psychologists can glean new perspectives from this intervention by understanding how internal experiences influence aggression in high-conflict couples, and clinicians may use it to assist couples in changing their conflict resolution methods from escalating and abusive to more constructive and respectful interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kraft pulping of Drimys winteri wood chips biotreated with Ganoderma australe

Drimys winteri, a native hardwood from Chile, presents some interesting characteristics that make it suitable for the pulp and paper industry. In this work, the potential of D winteri for the conventional kraft and biokraft pulp production was evaluated. For biokraft pulping, wood chips were biotreated with the white‐rot fungus Ganoderma australe. During the biotreatment, a selective pattern of biodelignification was observed and the wood chips biotreated for 15, 30 and 45 days were submitted to kraft cooking. At low cooking severity (H‐factor below 1500 h^?1, 15% active alkali and 25% sulfidity), all biopulps presented lower kappa numbers than control pulps and approximately the same screened pulp yield. Biopulps were easily refined in a PFI mill, requiring less PFI revolutions to achieve the same fibrillation degree. The strength properties of the biopulps were similar to those of the control pulps. Copyright © 2005 Society of Chemical Industry