An approach for configuring space photovoltaic tandem arrays based on cell layer performance

Meeting solar array performance goals of 300 W/Kg requires use of solar cells with orbital efficiencies greater than 20 percent. Only multijunction cells and cell layers operating in tandem produce this required efficiency. An approach for defining solar array design concepts that use tandem cell layers involve the following: transforming cell layer performance at standard test conditions to on-orbit performance; optimizing circuit configuration with tandem cell layers; evaluating circuit sensitivity to cell current mismatch; developing array electrical design around selected circuit; and predicting array orbital performance including seasonal variations

Method of fabricating a photovoltaic module of a substantially transparent construction

A method characterized by the steps of positioning a plurality of uniformly dimensioned photovoltaic cells in registered relation with a plurality of openings formed in a planar tool is disclosed. The method allows acess to the P contact surface of each of the cells. The steps of the method are: (1) connecting the N contact surface of alternate cells to the P contact surface of the cells interposed therebetween, (2) removing therefrom residue of solder flux, (3) applying to the N contact surfaces of the cells a transparent adhesive, (4) placing a common transparent cover plate in engaged relation with the adhesive, (5) placing a film over the circular openings for hermetically sealing the openings, and (6) establishing a vacuum between the film and the cover plate

Lightweight solar array blanket tooling, laser welding and cover process technology

A two phase technology investigation was performed to demonstrate effective methods for integrating 50 micrometer thin solar cells into ultralightweight module designs. During the first phase, innovative tooling was developed which allows lightweight blankets to be fabricated in a manufacturing environment with acceptable yields. During the second phase, the tooling was improved and the feasibility of laser processing of lightweight arrays was confirmed. The development of the cell/interconnect registration tool and interconnect bonding by laser welding is described

Fundamentals of Flakeboard Manufacture: Viscoelastic Behavior of the Wood Component

Theories of the viscoelastic behavior of amorphous polymers are reviewed and are used to describe the density gradient formation in flakeboard. This technique utilizes measured temperature and gas pressure at discrete locations inside a flake mat during hot pressing to predict the glass transition temperature of wood as a function of press time. The difference between the flake temperature and the predicted glass transition temperature is a relative indicator of the amount of flake deformation and stress relaxation at a location in the mat. A knowledge of the stress history imposed in the mat is then used to relate flake deformation and stress relaxation to the formation of a density gradient. This analysis allows for a significant portion of the density gradient to develop after the hot press has closed. Experimental data for various density gradients support the theories presented here

Fundamental Aspects of Wood Deformation Pertaining To Manufacture of Wood-Based Composites

During processing, wood-based composites are pressed using extreme heat and pressure for varying lengths of time. Evidence exists that the environmental conditions under which the wood densifies can alter the properties of both the solid wood and the composite product. Given the larger number and extreme nature of variables that exist during composite manufacture, it is imperative that the deformation process be understood from a fundamental standpoint. The objective of this research was to determine the applicability of basic materials engineering theory to the viscoelastic deformation of wood in transverse compression under a variety of temperatures and moisture contents.Theories of cellular solids were used to model the nonlinear compression behavior of small wood elements. For low-density woods, it was determined that cellular collapse can result from elastic buckling of the cell wall. The dependence of inelastic behavior of the gross wood on the elastic properties of the cell wall allows the time, temperature, and moisture dependence to be modeled with classical linear viscoelastic theory of amorphous polymers. Time-temperature-moisture superposition was shown to be applicable to stress relaxation data collected for temperatures between 39 and 99 C and moisture contents between 3 and 16%. The shift factors derived were described using free volume and entropy-based equations. This research demonstrates that wood behaves similarly under those conditions to the general class of cellular amorphous polymers. This conclusion opens many possibilities for experimentally and mathematically modeling the pressing of wood-based composites

4-(8-Eth­oxy-2,3-dihydro-1H-cyclo­penta­[c]quinolin-4-yl)butane-1-peroxol

In the title mol­ecule, C18H23NO3, the hydro­per­oxy­butyl substituent is nearly fully extended, with the four torsion angles in the range 170.23 (10)–178.71 (9)°. The O—O distance in the hydro­peroxide group is 1.4690 (13) Å. This group acts as an inter­molecular hydrogen-bond donor to a quinoline N atom. This results in dimeric units about the respective inversion centers, with graph-set notation R 2 2(18)

Mixed-Mode I + II fracture characterization of bonded joints using a novel Multi-Mode Apparatus

The present work presents the experimental test results to assess the toughness of an adhesive joint, using a previouslydefined crack equivalent data reduction scheme applied to a new multi-mode apparatus, inspired in a load jig previouslydeveloped by Fernlund and Spelt. The patented jig allows for easy alteration of the mode-mixity and permits coveringthe full range of mixed-mode I+II combinations. A data reduction scheme based on specimen compliance, beam theoryand crack equivalent concept is used to overcome several difficulties inherent to the test analysis. The method assumesthat the performed test can be viewed as a combination of the double cantilever beam and asymmetrically loaded endnotchedflexure tests, which provide modes I and II fracture characterization, respectively. A numerical analysisincluding a cohesive mixed-mode I+II damage model was performed considering different mixed-mode loadingconditions to validate the proposed data reduction scheme. Issues regarding self-similar crack growth and fractureprocess zone development are discussed. It was verified that the considered in-plane mix mode fracture criterion is wellcaptured using the proposed data reduction scheme

Structural and Functional Features of a Developmentally Regulated Lipopolysaccharide-Binding Protein

ABSTRACT Mammalian lipopolysaccharide (LPS) binding proteins (LBPs) occur mainly in extracellular fluids and promote LPS delivery to specific host cell receptors. The function of LBPs has been studied principally in the context of host defense; the possible role of LBPs in nonpathogenic host-microbe interactions has not been well characterized. Using the Euprymna scolopes-Vibrio fischeri model, we analyzed the structure and function of an LBP family protein, E. scolopes LBP1 (EsLBP1), and provide evidence for its role in triggering a symbiont-induced host developmental program. Previous studies showed that, during initial host colonization, the LPS of V. fischeri synergizes with peptidoglycan (PGN) monomer to induce morphogenesis of epithelial tissues of the host animal. Computationally modeled EsLBP1 shares some but not all structural features of mammalian LBPs that are thought important for LPS binding. Similar to human LBP, recombinant EsLBP1 expressed in insect cells bound V. fischeri LPS and Neisseria meningitidis lipooligosaccharide (LOS) with nanomolar or greater affinity but bound Francisella tularensis LPS only weakly and did not bind PGN monomer. Unlike human LBP, EsLBP1 did not bind N. meningitidis LOS:CD14 complexes. The eslbp1 transcript was upregulated ~22-fold by V. fischeri at 24 h postinoculation. Surprisingly, this upregulation was not induced by exposure to LPS but, rather, to the PGN monomer alone. Hybridization chain reaction-fluorescent in situ hybridization (HCR-FISH) and immunocytochemistry (ICC) localized eslbp1 transcript and protein in crypt epithelia, where V. fischeri induces morphogenesis. The data presented here provide a window into the evolution of LBPs and the scope of their roles in animal symbioses. IMPORTANCE Mammalian lipopolysaccharide (LPS)-binding protein (LBP) is implicated in conveying LPS to host cells and potentiating its signaling activity. In certain disease states, such as obesity, the overproduction of this protein has been a reliable biomarker of chronic inflammation. Here, we describe a symbiosis-induced invertebrate LBP whose tertiary structure and LPS-binding characteristics are similar to those of mammalian LBPs; however, the primary structure of this distantly related squid protein (EsLBP1) differs in key residues previously believed to be essential for LPS binding, suggesting that an alternative strategy exists. Surprisingly, symbiotic expression of eslbp1 is induced by peptidoglycan derivatives, not LPS, a pattern converse to that of RegIIIγ, an important mammalian immunity protein that binds peptidoglycan but whose gene expression is induced by LPS. Finally, EsLBP1 occurs along the apical surfaces of all the host’s epithelia, suggesting that it was recruited from a general defensive role to one that mediates specific interactions with its symbiont