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A surprisingly high degree of structural and compositional dynamics is observed in the system LiBH 4 -LiCl as a function of temperature and time. Rietveld refinement of synchrotron radiation powder X-ray diffraction (SR-PXD) data reveals that Cl -readily substitutes for BH 4 -in the structure of LiBH 4 . Prolonged heating a sample of LiBH 4 -LiCl (1:1 molar ratio) above the phase transition temperature and below the melting point (108 < T < 275°C) can produce highly chloride substituted hexagonal lithium borohydride, h-Li(BH 4 ) 1-x Cl x , e.g., x ∼ 0.42, after heating from room temperature (RT) to 224°C at 2.5°C/min. LiCl has a higher solubility in h-LiBH 4 as compared to orthorhombic lithium borohydride, o-LiBH 4 , which is illustrated by a LiBH 4 -LiCl (1:1) sample equilibrated at 245°C for 24 days and left at RT for another 13 months. Rietveld refinement reveals that this sample contains o-Li(BH 4 ) 0.91 Cl 0.09 and LiCl. This illustrates a significantly faster dissolution of LiCl in h-LiBH 4 as compared to a slower segregation of LiCl from o-LiBH 4 , which is also demonstrated by in situ SR-PXD from three cycles of heating and cooling of the same Li(BH 4 ) 0.91 Cl 0.09 sample. The substitution of the smaller Cl -for the larger BH 4 -ion is clearly observed as a reduction in the unit cell volume as a function of time and temperature. A significant stabilization of h-LiBH 4 is found to depend on the degree of anion substitution. Variable temperature solid-state magic-angle spinning (MAS) 7 Li and 11 B NMR experiments on pure LiBH 4 show an increase in full width at half maximum (fwhm) when approaching the phase transition from o-to h-LiBH 4 , which indicates an increase of the relaxation rate (i.e., T 2 decreases). A less pronounced effect is observed for ion-substituted Li(BH 4 ) 1-x Cl x , 0.09 < x < 0.42. The MAS NMR experiments also demonstrate a higher degree of motion in the hexagonal phase, i.e., fwhm is reduced by more than a factor of 10 at the o-to h-LiBH 4 phase transition.

This paper describes new sample cells and techniques for in situ powder X-ray diffraction specifically designed for gas absorption studies up to ca 300 bar (1 bar = 100 000 Pa) gas pressure. The cells are for multipurpose use, in particular the study of solid-gas reactions in dosing or flow mode, but can also handle samples involved in solid-liquid-gas studies. The sample can be loaded into a single-crystal sapphire (Al 2 O 3 ) capillary, or a quartz (SiO 2 ) capillary closed at one end. The advantages of a sapphire single-crystal cell with regard to rapid pressure cycling are discussed, and burst pressures are calculated and measured to be $300 bar. An alternative and simpler cell based on a thin-walled silicate or quartz glass capillary, connected to a gas source via a VCR fitting, enables studies up to $100 bar. Advantages of the two cell types are compared and their applications are illustrated by case studies.

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Lithium tetrahydridoboranate (LiBH 4 ) may be a potentially interesting material for hydrogen storage, but in order to absorb and desorb hydrogen routinely and reversibly, the kinetics and thermodynamics need to be improved significantly. A priori, this material has one of the highest theoretical gravimetric hydrogen contents, 18.5 wt %, but unfortunately for practical applications, hydrogen release occurs at too high temperature in a non-reversible way. By means of in situ synchrotron radiation powder X-ray diffraction (SR-PXD), the interaction between LiBH 4 and different additivessSiO 2 , TiCl 3 , LiCl, and Ausis investigated. It is found that silicon dioxide reacts with molten LiBH 4 and forms Li 2 SiO 3 or Li 4 SiO 4 at relatively low amounts of SiO 2 , e.g., with 5.0 and 9.9 mol % SiO 2 in LiBH 4 , whereas, for higher amounts of SiO 2 (e.g., 25.5 mol %), only the Li 2 SiO 3 phase is observed. Furthermore, we demonstrate that a solid-state reaction occurs between LiBH 4 and TiCl 3 to form LiCl at room temperature. At elevated temperatures, more LiCl is formed simultaneously with a decrease in the diffracted intensity from TiCl 3 . Lithium chloride shows some solubility in solid LiBH 4 at T > 100°C. This is the first report of substituents that accommodate the structure of LiBH 4 by a solid/solid dissolution reaction. Gold is found to react with molten LiBH 4 forming a Li-Au alloy with CuAu 3 -type structure. These studies demonstrate that molten LiBH 4 has a high reactivity, and finding a catalyst for this H-rich system may be a challenge.

The Learning Factory is a new practice‐based curriculum and physical facilities for product realization. Its goal is to provide an improved educational experience that emphasizes the interdependency of manufacturing and design in a business environment. The Learning Factory is the product of the Manufacturing Engineering Education Partnership (MEEP). This partnership is a unique collaboration of three major universities with strong engineering programs (Penn State, University of Puerto Rico‐Mayaguez, University of Washington), a premier high‐technology government laboratory (Sandia National Laboratories), over 100 corporate partners covering a wide spectrum of U.S. Industries, and the federal government that provided funding for this project through the ARPA Technology Reinvestment Program. As a result of this initiative, over 14,000 square feet of Learning Factory facilities have been built or renovated across the partner schools. In the first two years of operation, the Learning Factories have served over 2600 students. Four new courses, and a revamped senior projects course which integrate manufacturing, design and business concerns and make use of these facilities have been instituted. These courses are an integral part of a new curriculum option in Product Realization. The courses were developed by a unique team approach and their materials are available electronically over the World Wide Web. Industry partners provide real‐world problems and are the customers for students in our senior capstone design courses. As of December 1996, over 200 interdisciplinary projects have been completed across the three schools. These projects involve teams of students from Industrial, Mechanical, Electrical, Chemical Engineering and Business. Forty‐three faculty members, across five time zones, are engaged in this effort.

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