Solar driven lasers for power satellite applications

The technological feasibility of using multimagawatt lasers for space power transmission is discussed. Candidate lasers include electric discharge lasers, direct optically pumped lasers, and free electron lasers

Crystal structure of poly[[[μ4-5-(9H-carbazol-9-yl)isophthalato][μ3-5-(9H-carbazol-9-yl)isophthalato]bis-(di-methyl-formamide)(methanol)dizinc] di-methyl-formamide monosolvate].

The structure of the polymeric title compound, {[Zn2(C20H11NO4)2(C3H7NO)2(CH3OH)]·C3H7NO} n , comprises carbazolylisophthalate moieties connecting dimetallic tetra-carboxyl-ate zinc secondary building units (SBUs) parallel to [100] and [010], leading to a layer-like arrangement parallel to (001). Each SBU consists of two Zn atoms in slightly distorted tetra-hedral and octa-hedral coordination environments [Zn⋯Zn = 3.5953 (6) Å]. Three carboxyl-ate groups bridge the two Zn atoms in a μ2-O:O' mode, whereas the fourth coordinates through a single carboxyl-ate O atom (μ1-O). The O atoms of two di-methyl-formamide (DMF) and one methanol mol-ecule complete the Zn coordination spheres. The methanol ligand inter-acts with the noncoordinating DMF mol-ecule via an O-H⋯O hydrogen bond of medium strength. Carbazoles between the layers inter-digitate through weak C-H⋯.π inter-actions to form a laminar solid stacked along [010]. Two kinds of C-H⋯π inter-actions are present, both with a distance of 2.64 Å, between the H atoms and the centroids, and a third C-H⋯π inter-action, where the aromatic H atom is located above the carbazole N-atom lone pair (H⋯N = 2.89 Å). Several C-H⋯O inter-actions occur between the coordinating DMF mol-ecule, the DMF solvent mol-ecule, and ligating carboxyl-ate O atoms

Self-Esteem and Relationship Perception

Fluctuations of state self-esteem, in-the-moment self-esteem, may influence our perceptions romantic relationships in either a positive or negative light. This research, using a subliminal priming task, aimed to test whether manipulation of state self-esteem would cause a significant difference in either relationship satisfaction or, if single, relationship perception. We expected individuals that had their self-esteem positively primed would have higher relationship satisfaction or relationship perception. We also expected a similar relationship for those who had their self-esteem negatively influenced. Some strong correlations were found between self-esteem and relationship satisfaction that leave implications for further research on this topic

Guides to Developing Service-Learning Programs

This document lists those guides in our collection which are most pertinent to service-learning. Each citation provides bibliographic information, an indication of the type of guide, a program grade level, and the source or sources where the guide can be obtained. If an abstract was available from the ERIC database or the author it is included. The next edition of this document will include a greater number of abstracts as our staff continues to abstract and index materials. The guides included in this document meet the following criteria: NSLCC has a copy of the resource on hand for reference by staff members and for cataloging purposes. The resource provides practical or instructive information which can be applied to other situations, and therefore, is classified as a guide. The resource\u27s format is print rather than video. The guide as a whole, or in part, directly discusses service-learning. The resource can currently be obtained either from the party responsible for producing it or from a secondary source such as a document delivery service. The NSLCC database contains records about other guides and media resources which are not included in this document. Guides which have not been included because they do not directly discuss service-learning, but do cover closely related topics such as dropout prevention or social action may be very useful. We can search the database individually to locate additional titles which meet specific purposes. Please call our toll-free number to request a search tailored to individual needs. The type of guide is assigned as follows: Program Development Guides are the most comprehensive, containing information about one or more administrative topics as well as information about curriculum and/or service activities. An Administrative Guide contains information about several administrative topics. Within this type there are several Administrative types which are more specific: - Collaboration, - Funding, - Legal Requirements, - Staffing or Training, and - Program Evaluation. A Content Development Guide assists in developing curriculum and service activities but does not include administrative topics. Two specific Content types focus on particular aspects of content development: - Curriculum, and - Service Activities

Guides to Developing Service-Learning Programs

This document lists those guides in our collection which are most pertinent to service-learning. Each citation provides bibliographic information, an indication of the type of guide, a program grade level, and the source or sources where the guide can be obtained. If an abstract was available from the ERIC database or the author it is included. The next edition of this document will include a greater number of abstracts as our staff continues to abstract and index materials. The guides included in this document meet the following criteria: NSLCC has a copy of the resource on hand for reference by staff members and for cataloging purposes. The resource provides practical or instructive information which can be applied to other situations, and therefore, is classified as a guide. The resource\u27s format is print rather than video. The guide as a whole, or in part, directly discusses service-learning. The resource can currently be obtained either from the party responsible for producing it or from a secondary source such as a document delivery service. The NSLCC database contains records about other guides and media resources which are not included in this document. Guides which have not been included because they do not directly discuss service-learning, but do cover closely related topics such as dropout prevention or social action may be very useful. We can search the database individually to locate additional titles which meet specific purposes. Please call our toll-free number to request a search tailored to individual needs. The type of guide is assigned as follows: Program Development Guides are the most comprehensive, containing information about one or more administrative topics as well as information about curriculum and/or service activities. An Administrative Guide contains information about several administrative topics. Within this type there are several Administrative types which are more specific: - Collaboration, - Funding, - Legal Requirements, - Staffing or Training, and - Program Evaluation. A Content Development Guide assists in developing curriculum and service activities but does not include administrative topics. Two specific Content types focus on particular aspects of content development: - Curriculum, and - Service Activities

Preparation, Cure, and Characterization of Cyanate Ester-Epoxy Blends

Cyanate ester resins are often blended with lower cost epoxy monomers in order to modify the cost, toughness, and processing characteristics. There are also several choices of catalysts that can be used to improve processing, namely by reducing the cure temperature. This study was undertaken to illustrate how a designed experiment approach can be used to systematically investigate a wide range of material combinations and illuminate the basic cure behavior of some simple cyanate ester – epoxy blend combinations. Two commercial cyanate ester resin products were obtained. Each was blended with a bisphenol F based epoxy resin at two different levels, and the effect of a hindered amine catalyst at low level was also investigated. This resulted in a 23 factorial experiment. Material characterization included differential scanning calorimetry (DSC) and thermal decomposition via thermogravimetric analysis (TGA). Although the addition of epoxy was expected to lower both the glass transition temperature and thermal stability (compared to pure cyanate), the designed experiment approach provided a good map of how these properties change as a function of epoxy substitution. For example, the amount of epoxy steadily decreased the Tg, TGA onset temperature, and char yield in an almost linear fashion from 0 to 50 wt%. Specifically, Tg was reduced by ~3°C per 1% epoxy, TGA onset temperature was reduced by ~1.2 °C per 1% epoxy, and char yield was reduced by ~0.5 wt% per 1% epoxy

Autecology, Development and Diagenesis of a Phylloid Stromatolitic Blue Green Algal bioherm, Laborcita formation, Sacramento Mountains, New Mexico

A Lower Permian phylloid algal bioherm, developed in the middle of the Laborcita Formation near Tularosa, New Mexico, is comprised of blue green algal bound phylloid algal wackestones and packstones. It contains a restricted fauna of erect, interlocking phylloid algae encrusted by wavy, digitate, and botryoidal masses of blue green algae and other minor epibionts. Primary void space developed in the bioherm as shelter cavities beneath phylloid algal thalli. Fan arrays of slightly radial fibrous cement, which appear as dark patches in the core rocks, developed in the submarine environment on masses of blue green algae and on phylloid plates and grew into the shelter cavities. They exhibit three stages of inversion and recrystallization which progressively obscure the original fibrous fabric. The intimate association between robust phylloid algae and encrusting blue green algae, penecontemporaneous marine cementation and infiltration of micrite and layered pelletal micrite between algal thalli controlled mound development. After deposition of the mound, subaerial diagenesis created an extensive network of interconnected solution voids which transect primary structures. Subsequently, the bioherm was saturated by fresh water below the water table where the solution voids were lined by a clear, equant to slightly bladed, isopachous cement. A second solution initiated neomorphism of micrite and allochems to microspar and precipitated a clear, coarsely crystalline, calcite mosaic in remaining void space

“Antes éramos de tierra firme”: community perspectives on the past, present, and future of Isla Narganá and Isla Corazón de Jesús, Comarca Guna Yala in the face of a changing climate

The objective of this research was to learn about Isla Narganá and Isla Corazón de Jesús, Comarca Guna Yala residents’ perspectives on climate change and, to learn about what needs to be done to mitigate the effects of climate change on the islands. In April 2022, eighteen semi-structured interviews were conducted in Spanish with residents of the islands. Interviews revealed that flooding caused by sea level rise, intensification of precipitation events, extreme heat, and biodiversity loss were the most reported impacts of climate change on participants’ lives. Poor waste management opportunities were also discussed as a critical environmental issue affecting the communities. In response to said environmental issues, community members reported negative feelings. Participants also reported that there is a lack of discussion related to climate change among the community. In terms of climate mitigation, participants discussed planned relocation to the mainland territory of Guna Yala. Participants also expressed the importance of educating the community, especially children, about climate change and related issues. This paper serves to share the stories, experiences, and ideas of community members on the islands. In the greater academic context of climate research, this paper aims to bring these perspectives into the academic discussion and deepen the understanding of what it means to be a frontline community

Development of a Simple Lab-Scale Vacuum Assisted Resin Transfer Molding (VARTM) Process

The goal of the current study was to develop and demonstrate a simple and quick lab-scale VARTM process for the purpose of making flat panels for subsequent characterization, for example in new materials development efforts. This process was not intended to be optimized for final production, rather it served as the quickest way to make lab-scale composite panels using VARTM while maintaining all the salient features of typical VARTM processes used in larger scale manufacturing. There is a wide variety of ways to implement VARTM, as well as a diverse list of potential materials and supplies from which to choose. The process we arrived at was implemented on a 60 cm x 90 cm (2 ft. x 3 ft.) aluminum plate, which was mounted to a moveable cart and intended for ambient temperature processing (no heaters). Details of the vacuum system, resin distribution strategy, and bagging procedures will be described herein. The system was tested by making carbon/epoxy composite laminates of approximately 30 cm x 45 cm (1 ft. x 1.5 ft.). These panels were tested for thickness variation and fiber volume fraction. Optical microscopy was also used to evaluate the microstructure, and limited tensile testing was performed. The results indicated that the panels were of reasonable quality with no significant porosity

Simulation of Laminated Object Manufacturing (LOM) with Variation of Process Parameters

A previously developed and verified thermal model for Laminated Object Manufacturing (LOM) was used to investigate the effects of various processing parameters on the temperature profile in a LOM part during the build cycle. The mathematical model, based on 3-dimensional transient heat conduction in a rectangular geometry LOM part, allows calculation ofthe transient temperature distribution within the part during the application of a new layer as well as during other periods ofthe LOM build cycle. The parameters roller temperature, roller speed, chamber air temperature, base plate temperature, and laser cutting time were independently varied, and the LOM process response simulated. The results were analyzed in order to gain insight into potential strategies for intelligent process control.Mechanical Engineerin