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Best Practices for Evaluating Flight Deck Interfaces for Transport Category Aircraft with Particular Relevance to Issues of Attention, Awareness, and Understanding CAST SE-210 Output 2 Report 6 of 6
Attention, awareness, and understanding of the flight crew are a critical contributor to safety and the flight deck plays a critical role in supporting these cognitive functions. Changes to the flight deck need to be evaluated for whether the changed device provides adequate support for these functions. This report describes a set of diverse evaluation methods. The report recommends designing the interface-evaluation to span the phases of the device development, from early to late, and it provides methods appropriate at each phase. It describes the various ways in which an interface or interface component can fail to support awareness as potential issues to be assessed in evaluation. It summarizes appropriate methods to evaluate different issues concerning inadequate support for these functions, throughout the phases of development.
Independent Assessment of Perception From External/non-NASA Systems Engineering (SE) Sources
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Factors that Influenced Airplane State Awareness Accidents and Incidents: CAST SE-210 Output 2: Report 2 of 6
This report is part of a series of reports that address flight deck design and evaluation, written as a response to loss of control accidents. In particular, this activity is directed at failures in airplane state awareness in which the pilot loses awareness of the airplane’s energy state or attitude and enters an upset condition. The Commercial Aviation Safety Team (CAST) created a team to analyze a set of incidents and accidents associated with the flight crew’s loss of awareness of aircraft attitude or energy state. The CAST activity focused on a set of 18 loss of control (LOC) accidents and incidents. In those events, the pilot seemed to lose awareness of the state of the airplane, especially related to its energy state or its attitude. To understand the roots of that loss of awareness, we analyzed the events in relation to a set of factors that were present in many of them. We show how these factors contributed to lost awareness. Then, we use that understanding to identify potentially useful changes to the flight deck interface and how those flight deck changes could be evaluated.
Evaluation Issues for a Flight Deck Interface; CAST SE-210 Output 2: Report 4 of 6
This report is part of a series of reports that addresses flight deck design and evaluation, written as a response to loss of control accidents. In particular, this activity is directed at failures in airplane state awareness, in which the pilot loses awareness of the airplane’s energy state or attitude and enters an upset condition. Another report in this series of reports speaks directly to flight deck evaluation methods and metrics for the types of attention and awareness issues that were revealed from the airplane state awareness events. In this report, we describe a wide range of flight deck evaluation issues tied to flight crew performance. The objectives are to establish a framework for thinking about how the flight deck interface should support the performance of the flight crew, and to aid the Federal Aviation Administration (FAA) in identifying relevant human performance issues during the evaluation/certification process. Issues are broken out into sections that cover physical ergonomics, design for usability, data integration and display content, attention and task management, flight crew problem solving, and flight crew teaming. For each issue, we recommend specific ways that the flight deck interface should support the flight crew. For each, we also identify existing 14 CFR Part 25 rules and guidance that are relevant to the issue. This allows the FAA to determine what current regulatory materials can support them in raising the issue with the applicant.
Mixed-Domain Charge Transport in S-Se Alloys as a Li-S Battery Cathode Material
Lithium-sulfur batteries are emerging candidate systems for the next-generation long-range electric aircraft application owing to their potential to deliver high energy density per weight. Their cathodes are to be made primarily with sulfur, but sulfur by itself has much too low electron conductivity to serve as a useful cathode. An idea that has been suggested to overcome this bottleneck is to alloy sulfur with selenium in the hope that electron mobility, which is thought to improve charge transport at some expense of increased weight and reduced energy density. However, understanding of these alloy structures and their transport mechanism is insufficient, and electron mobility at varying degrees of selenium content is not well charted, which are critical for determining the optimum selenium content and testing whether this strategy is generally feasible. The difficulty of computationally characterizing these alloy systems is rooted in the structure. The structures of both sulfur and selenium exhibit eight-atom rings that pack together in various orientations to form their respective crystals. For one, because these crystals (and presumably their alloys as well) feature multiple polymorphs such that their structural coherence is rather unclear. Secondly, these are also relatively large systems (32 atoms per cell) with low-symmetry, which complicate computation both in terms of accuracy and efficiency. Thirdly, such semi-molecular, semi-crystalline structures lead to a combination of band-transport characteristics and hopping-transport characteristics, each of which is a domain with its own physics and set of computational, theoretical challenges. In addition, there is a general dearth of experimental transport data for sulfur-selenium alloys. In this study, we make a comprehensive attempt to tackle this problem using a wide array of first-principles methods. We generate special quasirandom structures to simulate alloy structures, and compute their first-principles Raman spectra for comparison with experimental data to ensure their structural soundness. We then proceed to use recently developed, state-of-the-art tool (AMSET) in order to efficiently compute electronic mobilities under band transport of pure sulfur, pure selenium, as well as their alloys of various compositions at a reasonable accuracy. We then sample numerous dimer configurations of nearest-neighbor eight-atom-ring-pairs and compute electronic hopping rates between them, which yields hopping mobility. A combination of these efforts lead to a general mapping of electron transport behaviors throughout the alloy range. Preliminary results show that introduction of selenium into sulfur initially damages electron mobility due to disorder but eventually improves it beyond that of pure sulfur with additional selenium content, ultimately peaking at the pure-selenium limit. Band transport dominates for holes in sulfur and electrons in selenium, but in all other cases, hopping transport is dominant. Ongoing efforts include determination of charge concentration and conductivity, as well as performing multiphysics modeling to determine the optimum selenium content for best tradeoff between conductivity and energy density for aircraft range.
Open-source Wireless Sensor Network (Wi-Se Net) for Flexible Deployment
Wireless sensors, especially if battery powered, have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Recent advances in wireless technology and microprocessor boards have produced a variety of inexpensive off-the shelf chips which can communicate wirelessly with simple protocols. This paper describes the design and implementation of a highly customizable wireless sensor network (called WiSe Net) using inexpensive open-source hardware components as wireless nodes. These wireless sensor nodes can transmit data at a rate <250 Hz, can be battery powered, and have a small footprint (2x5 cm). In addition, a preliminary over-the-air programming system was developed to allow for simple wireless configuration when active. The network performance was demonstrated by taking distributed and electrically isolated temperature measurements on a high-voltage lab apparatus. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring
Open-source Wireless Sensor Network (Wi-Se Net) for Flexible Deployment
Wireless sensors, especially if battery powered, have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Recent advances in wireless technology and microprocessor boards have produced a variety of inexpensive off-the shelf chips which can communicate wirelessly with simple protocols. This paper describes the design and implementation of a highly customizable wireless sensor network (called WiSe Net) using inexpensive open-source hardware components as wireless nodes. These wireless sensor nodes can transmit data at a rate <250 Hz, can be battery powered, and have a small footprint (2x5 cm). In addition, a preliminary over-the-air programming system was developed to allow for simple wireless configuration when active. The network performance was demonstrated by taking distributed and electrically isolated temperature measurements on a high-voltage lab apparatus. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring.
Autonomous Constrained Control for Arbitrary Configurations of Gimbaling Thrusters in SE(3)
In order to develop robust autonomy in spacecraft, it is desirable to develop methods for controlling a spacecraft in various configurations with any combination of thrusters of various types and both for static RCS thrusters and gimbaling thrusters. In the case of a stuck thruster imposing unplanned and undesired motion both translational and rotational or in the case of a malfunctioning thruster, it is desirable for that spacecraft to have the ability to identify and overcome that problem without human intervention. To that end, a spacecraft must be able to rapidly and autonomously reconfigure thruster firing histories and update guidance protocols. In this paper, a method for a spacecraft to autonomously select thrusters of any configuration is presented. The residual motion imposed by off-nominal or not-fully-controllable thruster configurations is identified by the spacecraft and solved for, both for static reaction control systems and gimbaling engines.
FTu4G.2 Ge 2 Sb 2 Se 4 Te-Based Reconfigurable On-Chip Metasurface NIR Filter
A tunable level, phase change material-based metasurface near IR optical filter on a transmissive doped silicon-on-insulator platform is demonstrated. This type of filter is non-volatile, non-mechanical, with switching being enabled by Joule heating via current pulses.
Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia
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Spin Reorientation in Antiferromagnetic MnPd 5 Se with an Anti-CeCoIn 5 Structure Type
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THE CORRELATION OF DETECTOR PERFORMANCE WITH1.1-EV TRAPS IN SE-ADDED CDTE COMPOUNDS
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ELECTROPHYSICAL PROPERTIES OF (CD,MN)(TE,SE) CRYSTALS
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Materials Data on K16Zr12Se61 by Materials Project
K16Zr12Se61 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.41–3.80 Å. In the second K site, K is bonded in a 8-coordinate geometry to seven Se atoms. There are a spread of K–Se bond distances ranging from 3.33–3.83 Å. In the third K site, K is bonded in a 10-coordinate geometry to ten Se atoms. There are a spread of K–Se bond distances ranging from 3.53–3.93 Å. In the fourth K site, K is bonded in a 7-coordinate geometry to seven Se atoms. There are a spread of K–Se bond distances ranging from 3.40–3.68 Å. In the fifth K site, K is bonded in a 6-coordinate geometry to nine Se atoms. There are a spread of K–Se bond distances ranging from 3.46–3.94 Å. In the sixth K site, K is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.34–3.63 Å. In the seventh K site, K is bonded in a 9-coordinate geometry to nine Se atoms. There are a spread of K–Se bond distances ranging from 3.35–3.87 Å. In the eighth K site, K is bonded in a 9-coordinate geometry to nine Se atoms. There are a spread of K–Se bond distances ranging from 3.38–3.80 Å. In the ninth K site, K is bonded to eight Se atoms to form distorted KSe8 hexagonal bipyramids that share a cornercorner with one ZrSe8 hexagonal bipyramid, corners with two ZrSe7 pentagonal bipyramids, edges with two ZrSe8 hexagonal bipyramids, and an edgeedge with one ZrSe7 pentagonal bipyramid. There are a spread of K–Se bond distances ranging from 3.34–3.71 Å. In the tenth K site, K is bonded in a 10-coordinate geometry to ten Se atoms. There are a spread of K–Se bond distances ranging from 3.38–3.87 Å. In the eleventh K site, K is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.36–3.62 Å. In the twelfth K site, K is bonded in a 7-coordinate geometry to seven Se atoms. There are a spread of K–Se bond distances ranging from 3.37–3.85 Å. In the thirteenth K site, K is bonded in a 7-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.35–3.96 Å. In the fourteenth K site, K is bonded in a 11-coordinate geometry to eleven Se atoms. There are a spread of K–Se bond distances ranging from 3.55–4.00 Å. In the fifteenth K site, K is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.29–3.77 Å. In the sixteenth K site, K is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.42–3.79 Å. There are twelve inequivalent Zr sites. In the first Zr site, Zr is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of Zr–Se bond distances ranging from 2.72–2.96 Å. In the second Zr site, Zr is bonded to seven Se atoms to form distorted ZrSe7 pentagonal bipyramids that share a cornercorner with one KSe8 hexagonal bipyramid, an edgeedge with one ZrSe7 pentagonal bipyramid, and a faceface with one ZrSe8 hexagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.60–2.87 Å. In the third Zr site, Zr is bonded to eight Se atoms to form distorted face-sharing ZrSe8 hexagonal bipyramids. There are a spread of Zr–Se bond distances ranging from 2.72–2.86 Å. In the fourth Zr site, Zr is bonded to eight Se atoms to form distorted ZrSe8 hexagonal bipyramids that share an edgeedge with one KSe8 hexagonal bipyramid and a faceface with one ZrSe7 pentagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.70–2.89 Å. In the fifth Zr site, Zr is bonded to seven Se atoms to form distorted ZrSe7 pentagonal bipyramids that share a cornercorner with one KSe8 hexagonal bipyramid, an edgeedge with one ZrSe8 hexagonal bipyramid, and a faceface with one ZrSe8 hexagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.58–2.93 Å. In the sixth Zr site, Zr is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of Zr–Se bond distances ranging from 2.73–2.98 Å. In the seventh Zr site, Zr is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of Zr–Se bond distances ranging from 2.72–2.98 Å. In the eighth Zr site, Zr is bonded to eight Se atoms to form distorted ZrSe8 hexagonal bipyramids that share a cornercorner with one KSe8 hexagonal bipyramid, an edgeedge with one ZrSe7 pentagonal bipyramid, and a faceface with one ZrSe8 hexagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.74–2.88 Å. In the ninth Zr site, Zr is bonded to eight Se atoms to form distorted ZrSe8 hexagonal bipyramids that share an edgeedge with one KSe8 hexagonal bipyramid and a faceface with one ZrSe7 pentagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.70–2.88 Å. In the tenth Zr site, Zr is bonded to eight Se atoms to form distorted face-sharing ZrSe8 hexagonal bipyramids. There are a spread of Zr–Se bond distances ranging from 2.72–2.88 Å. In the eleventh Zr site, Zr is bonded to seven Se atoms to form distorted ZrSe7 pentagonal bipyramids that share an edgeedge with one KSe8 hexagonal bipyramid, an edgeedge with one ZrSe7 pentagonal bipyramid, and a faceface with one ZrSe8 hexagonal bipyramid. There are a spread of Zr–Se bond distances ranging from 2.60–2.88 Å. In the twelfth Zr site, Zr is bonded in a 8-coordinate geometry to eight Se atoms. There are a spread of Zr–Se bond distances ranging from 2.71–2.94 Å. There are sixty-one inequivalent Se sites. In the first Se site, Se is bonded in a 6-coordinate geometry to two K, two Zr, and two Se atoms. There are one shorter (2.46 Å) and one longer (2.94 Å) Se–Se bond lengths. In the second Se site, Se is bonded in a 1-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.41 Å. In the third Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.48 Å. In the fourth Se site, Se is bonded in a 6-coordinate geometry to two K, two Zr, and two Se atoms. The Se–Se bond length is 2.86 Å. In the fifth Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.42 Å. In the sixth Se site, Se is bonded in a 1-coordinate geometry to two K, one Zr, and one Se atom. The Se–Se bond length is 2.40 Å. In the seventh Se site, Se is bonded in a 2-coordinate geometry to two K, one Zr, and two Se atoms. The Se–Se bond length is 2.42 Å. In the eighth Se site, Se is bonded in a 4-coordinate geometry to two K, one Zr, and one Se atom. In the ninth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.42 Å. In the tenth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. In the eleventh Se site, Se is bonded in a 1-coordinate geometry to three K, one Zr, and two Se atoms. The Se–Se bond length is 2.42 Å. In the twelfth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. In the thirteenth Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. In the fourteenth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. The Se–Se bond length is 2.40 Å. In the fifteenth Se site, Se is bonded in a 2-coordinate geometry to two K, one Zr, and two Se atoms. There are one shorter (2.45 Å) and one longer (2.95 Å) Se–Se bond lengths. In the sixteenth Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.45 Å. In the seventeenth Se site, Se is bonded in a 5-coordinate geometry to three K and two Zr atoms. In the eighteenth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. The Se–Se bond length is 2.43 Å. In the nineteenth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.43 Å. In the twentieth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. In the twenty-first Se site, Se is bonded in a 4-coordinate geometry to two K, two Zr, and one Se atom. In the twenty-second Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.43 Å. In the twenty-third Se site, Se is bonded in a 1-coordinate geometry to four K, one Zr, and one Se atom. In the twenty-fourth Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. In the twenty-fifth Se site, Se is bonded in a 5-coordinate geometry to three K and two Zr atoms. In the twenty-sixth Se site, Se is bonded in a 6-coordinate geometry to two K, two Zr, and two Se atoms. There are one shorter (2.47 Å) and one longer (2.96 Å) Se–Se bond lengths. In the twenty-seventh Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. In the twenty-eighth Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. In the twenty-ninth Se site, Se is bonded in a 2-coordinate geometry to two K, one Zr, and one Se atom. In the thirtieth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.43 Å. In the thirty-first Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. In the thirty-second Se site, Se is bonded in a 1-coordinate geometry to two K, one Zr, and two Se atoms. There are one shorter (2.41 Å) and one longer (2.89 Å) Se–Se bond lengths. In the thirty-third Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.45 Å. In the thirty-fourth Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.39 Å. In the thirty-fifth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.47 Å. In the thirty-sixth Se site, Se is bonded in a 6-coordinate geometry to two K, two Zr, and two Se atoms. In the thirty-seventh Se site, Se is bonded in a 6-coordinate geometry to two K, two Zr, and two Se atoms. The Se–Se bond length is 2.47 Å. In the thirty-eighth Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.41 Å. In the thirty-ninth Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. In the fortieth Se site, Se is bonded in a 2-coordinate geometry to three K, one Zr, and one Se atom. In the forty-first Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.42 Å. In the forty-second Se site, Se is bonded in a 2-coordinate geometry to three K, one Zr, and one Se atom. The Se–Se bond length is 2.39 Å. In the forty-third Se site, Se is bonded in a 5-coordinate geometry to three K, one Zr, and one Se atom. In the forty-fourth Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. In the forty-fifth Se site, Se is bonded in a distorted trigonal bipyramidal geometry to three K and two Zr atoms. In the forty-sixth Se site, Se is bonded in a 2-coordinate geometry to two K, two Zr, and one Se atom. In the forty-seventh Se site, Se is bonded in a 2-coordinate geometry to two K, one Zr, and two Se atoms. In the forty-eighth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. In the forty-ninth Se site, Se is bonded in a 5-coordinate geometry to two K, two Zr, and one Se atom. The Se–Se bond length is 2.42 Å. In the fiftieth Se site, Se is bonded in a 4-coordinate geometry to one K, two Zr, and one Se atom. The Se–Se bond length is 2.40 Å. In the fifty-first Se site, Se is bonded in a 1-coordinate geometry to three K, one Zr, and two Se atoms. The Se–Se bond length is 2
Materials Data on Dy6Se11 by Materials Project
Dy6Se11 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twenty-four inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.98–3.14 Å. In the second Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.96–3.00 Å. In the third Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.94–3.03 Å. In the fourth Dy3+ site, Dy3+ is bonded in a distorted pentagonal bipyramidal geometry to seven Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.89–2.99 Å. In the fifth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.93–3.00 Å. In the sixth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.95–3.13 Å. In the seventh Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.94–3.13 Å. In the eighth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.94–3.25 Å. In the ninth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.93–3.08 Å. In the tenth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.95–2.99 Å. In the eleventh Dy3+ site, Dy3+ is bonded in a pentagonal bipyramidal geometry to seven Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.87–2.93 Å. In the twelfth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.94–3.08 Å. In the thirteenth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.95–3.25 Å. In the fourteenth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.95–3.20 Å. In the fifteenth Dy3+ site, Dy3+ is bonded in a pentagonal bipyramidal geometry to seven Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.86–2.95 Å. In the sixteenth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.93–3.03 Å. In the seventeenth Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.95–3.18 Å. In the eighteenth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.92–3.00 Å. In the nineteenth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.92–3.03 Å. In the twentieth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.92–3.03 Å. In the twenty-first Dy3+ site, Dy3+ is bonded in a 9-coordinate geometry to nine Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.96–3.12 Å. In the twenty-second Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.97–3.04 Å. In the twenty-third Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.92–3.01 Å. In the twenty-fourth Dy3+ site, Dy3+ is bonded in a 8-coordinate geometry to eight Se+1.64- atoms. There are a spread of Dy–Se bond distances ranging from 2.93–3.05 Å. There are forty-four inequivalent Se+1.64- sites. In the first Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the second Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the third Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the fourth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the fifth Se+1.64- site, Se+1.64- is bonded in a 5-coordinate geometry to five Dy3+ atoms. In the sixth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the seventh Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the eighth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to three Dy3+ and one Se+1.64- atom. The Se–Se bond length is 2.46 Å. In the ninth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ and one Se+1.64- atom. The Se–Se bond length is 2.55 Å. In the tenth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the eleventh Se+1.64- site, Se+1.64- is bonded in a 6-coordinate geometry to four Dy3+ atoms. In the twelfth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ and one Se+1.64- atom. In the thirteenth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ and one Se+1.64- atom. The Se–Se bond length is 2.84 Å. In the fourteenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the fifteenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the sixteenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the seventeenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the eighteenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the nineteenth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the twentieth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the twenty-first Se+1.64- site, Se+1.64- is bonded in a 6-coordinate geometry to four Dy3+ and two Se+1.64- atoms. The Se–Se bond length is 2.54 Å. In the twenty-second Se+1.64- site, Se+1.64- is bonded in a 6-coordinate geometry to four Dy3+ atoms. In the twenty-third Se+1.64- site, Se+1.64- is bonded in a 2-coordinate geometry to four Dy3+ and one Se+1.64- atom. In the twenty-fourth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ and one Se+1.64- atom. The Se–Se bond length is 2.85 Å. In the twenty-fifth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the twenty-sixth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the twenty-seventh Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the twenty-eighth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the twenty-ninth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the thirtieth Se+1.64- site, Se+1.64- is bonded in a 5-coordinate geometry to five Dy3+ atoms. In the thirty-first Se+1.64- site, Se+1.64- is bonded in a 6-coordinate geometry to four Dy3+ and two Se+1.64- atoms. The Se–Se bond length is 2.53 Å. In the thirty-second Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the thirty-third Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ and one Se+1.64- atom. In the thirty-fourth Se+1.64- site, Se+1.64- is bonded in a 6-coordinate geometry to four Dy3+ atoms. In the thirty-fifth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the thirty-sixth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the thirty-seventh Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the thirty-eighth Se+1.64- site, Se+1.64- is bonded in a 5-coordinate geometry to five Dy3+ atoms. In the thirty-ninth Se+1.64- site, Se+1.64- is bonded in a 5-coordinate geometry to five Dy3+ atoms. In the fortieth Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the forty-first Se+1.64- site, Se+1.64- is bonded to five Dy3+ atoms to form a mixture of distorted edge and corner-sharing SeDy5 trigonal bipyramids. In the forty-second Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the forty-third Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to four Dy3+ atoms. In the forty-fourth Se+1.64- site, Se+1.64- is bonded in a 4-coordinate geometry to three Dy3+ and one Se+1.64- atom.