Characterizing transmissive diamond gratings as beam splitters for the hard X-ray single-shot spectrometer of the European XFEL

The European X-ray Free Electron Laser (EuXFEL) offers intense, coherent femtosecond pulses, resulting in characteristic peak brilliance values a billion times higher than that of conventional synchrotron facilities. Such pulses result in extreme peak radiation levels of the order of terawatts cm−2 for any optical component in the beam and can exceed the ablation threshold of many materials. Diamond is considered the optimal material for such applications due to its high thermal conductivity (2052 W mK−1 at 300 K) and low absorption for hard X-rays. Grating structures were fabricated on free-standing CVD diamond of 10 µm thickness with 500 µm silicon substrate support. The grating structures were produced by electron-beam lithography at the Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, Switzerland. The grating lines were etched to a depth of 1.2 µm, resulting in an aspect ratio of 16. The characterization measurements with X-rays were performed on transmissive diamond gratings of 150 nm pitch at the P10 beamline of PETRA III, DESY. In this paper, the gratings are briefly described, and a measured diffraction efficiency of 0.75% at 6 keV in the first-order diffraction is shown; the variation of the diffraction efficiency across the grating surface is presented.

Monolithic substrate support catalyst design considerations for steam methane reforming operation

This paper reviews the research undertaken to study the design criteria that address the monolithic support structure requirements in steam reforming operation for the effective mass transfer of process gases to the active sites and effective conductive heat transfer through tube wall to the active catalytic areas, as well as low pressure drop operation. Design considerations include selection of substrate materials that possess good mechanical strength to withstand the severe reaction conditions and prevent catalyst crushing that would lead to carbon formation and catalyst deactivation, and excessive heating of the tube that results in hot spots which is fatal to tube lifetime. The support’s mechanical properties are listed for the purpose of providing guidelines on verifying the structure durability. The practical aspect of packaging and stacking the monolith structures in the reformer tube for ease of loading and discharge is discussed to understand its readiness in industrial application.

Gibberellic Acid Production by Different Fermentation Systems Using Citric Pulp as Substrate/Support

Gibberellic acid (GA3) is an important phytohormone, a member of gibberellins family, which acts as a promoter and regulator of plant growth. This study aimed to evaluate GA3 production by Fusarium moniliforme LPB03 and Gibberella fujikuroi LPB06 using different techniques of fermentation, solid state fermentation (SSF), submerged fermentation (SmF), and semisolid state fermentation (SSSF), and different types of bioreactors. In all techniques, citric pulp (CP), a subproduct obtained from the extraction of orange juice, was employed as the substrate/support. GA3 production by SSF reached 7.60 g kg−1 and 7.34 g kg−1 in Erlenmeyer flasks and column bioreactors, respectively. For SmF, the highest concentration of GA3 obtained was 236.00 mg L−1 in Erlenmeyer flasks, 273.00 mg L−1 in a 10 L stirred tank reactor (STR), and 203.00 mg L−1 in a 1.5 L bubble column reactor (BCR). SSSF was conducted with a CP suspension. In this case, GA3 concentration reached 331.00 mg L−1 in Erlenmeyer flasks and 208 mg L−1 in a BCR. The choice of the fermentation technique is undoubtedly linked to the characteristics and productivity of each process. The methods studied are inexpensive and were found to produce good proportions of GA3, making them suitable for several applications.