In this lecture , the focus is on geological aspects of minerals. We are going to discuss about the crystal symmetry of minerals,axis of rotation , axis of rotoinversion symmetry y, and mirror plane. The crystal classes may be sub-divided into one of 6 crystal systems namely Triclinic, monoclinic, orthorhombic, tetragonal, hexagonal and isometric (cubic).
Crystallographic axis
The identification of specific symmetry operations enables one to orientate a crystal according g to an imaginary set of reference lines known as the crystallographic axis.With the exception of the hexagonal system, the axes are designated designated The ends of each a, b, and c. The ends of each axes are designated axes are designated + or -. This is important for the derivation of Miller Indices.
The document discusses various topics related to crystals, including:
- Crystals have a periodic arrangement of atoms and can have regular shapes categorized by symmetry. Pharmaceutical crystals often have irregular dendritic shapes.
- There are seven crystal systems categorized by symmetry elements like axes and planes. The main systems discussed are cubic, tetragonal, orthorhombic, monoclinic, triclinic, rhombohedral, and hexagonal.
- Unit cells are the smallest repeating units that make up the overall crystal structure. They can be primitive, containing one lattice point, or non-primitive with multiple points.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D.
- The 6 crystal systems that describe how unit cells are arranged in 3D space through translations.
- The 14 Bravais lattices that result from different combinations of unit cell arrangements.
- Space groups which incorporate additional symmetry operators like glide planes and screw axes to fully describe the internal atomic structure of crystals.
- How crystallography relates to understanding the internal ordering of atoms in minerals and how this ordering influences their physical properties.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D. M.C. Escher's works illustrate these concepts.
- There are 14 possible Bravais lattices that result from combining the 6 crystal systems with different arrangements of lattice points in 3D space.
- Space groups incorporate additional symmetry operators like glide planes and screw axes, resulting in 230 possible space groups that describe the internal atomic structure and arrangement in crystals.
- Crystallography describes the ordered internal structure of minerals, which produces diagnostic optical and chemical properties that can be used to identify unknown samples.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D. M.C. Escher's works illustrate these concepts.
- There are 14 possible Bravais lattices that result from combining the 6 crystal systems with different arrangements of lattice points in 3D space.
- Space groups incorporate additional symmetry operators like glide planes and screw axes, resulting in 230 possible space groups that describe the internal atomic structure and arrangement in crystals.
- Crystallography describes the ordered internal structure of minerals, which produces diagnostic optical and chemical properties that can be used to identify unknown samples.
The document discusses several topics related to crystals:
- Crystals are solid structures composed of periodic arrangements of atoms that can form regular geometric shapes. Common crystal shapes include cubic, hexagonal, and tetragonal.
- Crystals exhibit symmetry properties including centers of symmetry, planes of symmetry, and axes of symmetry. These symmetries are used to classify crystals into seven crystal systems.
- Important crystal systems include cubic, tetragonal, orthorhombic, monoclinic, triclinic, and hexagonal. Unit cells define the basic repeating structure of crystals and can be primitive or non-primitive.
- Crystals are grown to specific sizes optimal for their intended use, such as 50μm
There are six crystal systems that classify the possible shapes of unit cells based on their symmetry: triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. Within each system there are a limited number of Bravais lattices that describe how points representing atoms can be arranged in three-dimensional periodic patterns. In total there are 14 possible Bravais lattices across all crystal systems that satisfy the symmetry and periodicity requirements for crystal structures.
1) The document discusses crystal symmetry and diffraction patterns. It defines key terms like crystal systems, unit cells, and centred unit cells.
2) There are seven crystal systems that crystals can belong to, depending on their symmetry properties. Each system has restrictions on the possible shapes and dimensions of the unit cell.
3) Diffraction patterns provide information about the crystal structure by revealing the symmetry and dimensions of the unit cell. Analyzing diffraction patterns is how crystal structures are solved.
Srishti Gupta presented on the symmetric properties of crystal systems. There are 7 crystal systems divided based on their point groups: cubic, hexagonal, tetragonal, orthorhombic, monoclinic, triclinic, and rhombohedral/trigonal. Each system is defined by characteristics like axis lengths and angles. Point groups describe the symmetry operations like rotation, reflection, inversion that leave crystals unchanged and there are 32 total point groups classified by these operations and their combinations.
The document discusses various topics related to crystals, including:
- Crystals have a periodic arrangement of atoms and can have regular shapes categorized by symmetry. Pharmaceutical crystals often have irregular dendritic shapes.
- There are seven crystal systems categorized by symmetry elements like axes and planes. The main systems discussed are cubic, tetragonal, orthorhombic, monoclinic, triclinic, rhombohedral, and hexagonal.
- Unit cells are the smallest repeating units that make up the overall crystal structure. They can be primitive, containing one lattice point, or non-primitive with multiple points.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D.
- The 6 crystal systems that describe how unit cells are arranged in 3D space through translations.
- The 14 Bravais lattices that result from different combinations of unit cell arrangements.
- Space groups which incorporate additional symmetry operators like glide planes and screw axes to fully describe the internal atomic structure of crystals.
- How crystallography relates to understanding the internal ordering of atoms in minerals and how this ordering influences their physical properties.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D. M.C. Escher's works illustrate these concepts.
- There are 14 possible Bravais lattices that result from combining the 6 crystal systems with different arrangements of lattice points in 3D space.
- Space groups incorporate additional symmetry operators like glide planes and screw axes, resulting in 230 possible space groups that describe the internal atomic structure and arrangement in crystals.
- Crystallography describes the ordered internal structure of minerals, which produces diagnostic optical and chemical properties that can be used to identify unknown samples.
This document discusses concepts in crystallography including:
- Motifs and how their repetition through translation creates symmetrical patterns in 3D. M.C. Escher's works illustrate these concepts.
- There are 14 possible Bravais lattices that result from combining the 6 crystal systems with different arrangements of lattice points in 3D space.
- Space groups incorporate additional symmetry operators like glide planes and screw axes, resulting in 230 possible space groups that describe the internal atomic structure and arrangement in crystals.
- Crystallography describes the ordered internal structure of minerals, which produces diagnostic optical and chemical properties that can be used to identify unknown samples.
The document discusses several topics related to crystals:
- Crystals are solid structures composed of periodic arrangements of atoms that can form regular geometric shapes. Common crystal shapes include cubic, hexagonal, and tetragonal.
- Crystals exhibit symmetry properties including centers of symmetry, planes of symmetry, and axes of symmetry. These symmetries are used to classify crystals into seven crystal systems.
- Important crystal systems include cubic, tetragonal, orthorhombic, monoclinic, triclinic, and hexagonal. Unit cells define the basic repeating structure of crystals and can be primitive or non-primitive.
- Crystals are grown to specific sizes optimal for their intended use, such as 50μm
There are six crystal systems that classify the possible shapes of unit cells based on their symmetry: triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. Within each system there are a limited number of Bravais lattices that describe how points representing atoms can be arranged in three-dimensional periodic patterns. In total there are 14 possible Bravais lattices across all crystal systems that satisfy the symmetry and periodicity requirements for crystal structures.
1) The document discusses crystal symmetry and diffraction patterns. It defines key terms like crystal systems, unit cells, and centred unit cells.
2) There are seven crystal systems that crystals can belong to, depending on their symmetry properties. Each system has restrictions on the possible shapes and dimensions of the unit cell.
3) Diffraction patterns provide information about the crystal structure by revealing the symmetry and dimensions of the unit cell. Analyzing diffraction patterns is how crystal structures are solved.
Srishti Gupta presented on the symmetric properties of crystal systems. There are 7 crystal systems divided based on their point groups: cubic, hexagonal, tetragonal, orthorhombic, monoclinic, triclinic, and rhombohedral/trigonal. Each system is defined by characteristics like axis lengths and angles. Point groups describe the symmetry operations like rotation, reflection, inversion that leave crystals unchanged and there are 32 total point groups classified by these operations and their combinations.
The document discusses crystal classes and systems. It states that crystals can be grouped into 32 classes based on their symmetry, and these classes can further be organized into six crystal systems based on their crystallographic axes. The six systems are isometric, tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic. The isometric system is described in more detail, including its defining features of equal length axes at right angles, five symmetry classes, common forms that develop like the cube and octahedron, and example minerals like galena and pyrite.
This document discusses crystallographic symmetry and classification. It defines common symmetry operations like reflection, rotation, inversion, and rotoinversion. It provides examples of symmetry notation for different crystal systems. Crystals are classified into six crystal systems and 32 crystal classes based on their unique combinations of symmetry operations and axes. Miller indices are used to describe crystal planes and forms.
This document discusses crystallographic symmetry and classification. It defines common symmetry operations like reflection, rotation, inversion, and rotoinversion. It provides examples of symmetry notation for different crystal systems. Crystals are classified into six crystal systems and 32 crystal classes based on their unique combinations of symmetry operations and axes. Miller indices are used to describe crystal planes and forms.
Structure of Crystal Lattice - K Adithi PrabhuBebeto G
The document discusses the structure of crystal lattices. It begins by defining a crystal as a solid whose constituents are arranged in a highly ordered microscopic structure called a crystal lattice. There are seven basic crystal systems based on symmetry elements. The document then discusses various types of unit cells including primitive and centered unit cells. It describes the 14 Bravais lattices and provides examples of body centered cubic, face centered cubic, and end centered cubic lattices. Finally, it summarizes the structures of sodium chloride and calcium fluoride crystals including their chemical formulas and coordination numbers.
This document discusses crystallography and crystal structure. It defines key terms like crystalline solids, amorphous solids, unit cell, crystal lattice, crystallographic planes, and Miller indices. It describes the seven crystal systems (cubic, tetragonal, orthorhombic, monoclinic, triclinic, hexagonal, trigonal) based on their symmetry characteristics. It also discusses crystal forms, symmetry operations like rotation axes and planes of symmetry, and the notation used to describe crystal planes and orientations.
There are six crystal systems based on the symmetry of the unit cell: triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. Each system has a specific set of characteristics for the lengths of the cell axes (a, b, c) and angles between them (α, β, γ). There are 14 possible arrangements, called Bravais lattices, for the positioning of lattice points within the unit cells of each system. The cubic system has the highest symmetry while triclinic has the lowest.
Crystal symmetry is defined by repeated patterns of atoms in a crystal structure. There are different types of symmetry operations including planes of symmetry, axes of symmetry, and centers of symmetry. Planes of symmetry divide the crystal into mirror images, axes of symmetry involve rotational symmetry, and centers of symmetry involve equidistance from a point. The six main crystal systems are defined by their unique combinations of symmetry elements and are classified from highest to lowest symmetry as isometric, tetragonal, orthorhombic, hexagonal, monoclinic, and triclinic. Miller indices and Weiss parameters are used to describe the orientation of crystal planes.
This document provides an introduction to crystallography. It defines crystallography as the study of crystals, which are solid substances with regular internal structures bounded by flat planar faces. The document outlines the key elements of crystals, including crystallographic axes, axial angles, crystal systems, symmetry elements, Miller indices, and habits. It also briefly discusses atomic structure, chemical bonding, and polymorphism as relevant concepts in crystallography.
This document provides an overview of crystallography. It defines key terms like crystalline solids, unit cell, space lattice, and basis. Crystalline solids have long-range order of atoms while amorphous solids do not. There are 7 crystal systems based on lattice parameters. Miller indices (hkl) are used to describe planes in a crystal lattice. Bragg's law relates the wavelength of X-rays to the diffraction pattern produced by the crystal structure. Common defects in crystal structures are discussed like vacancies, interstitials, and Frenkel and Schottky defects. Methods for determining crystal structures include X-ray crystallography and powder diffraction.
The document discusses crystal structure and X-ray diffraction. It defines crystalline and amorphous solids, and provides examples of each. Crystalline solids have an orderly repeating pattern of atoms extending in three dimensions, while amorphous solids have short-range order only. The document also discusses crystal properties, space lattices, unit cells, Bravais lattices, coordination numbers, atomic packing factors, and the seven crystal systems. Finally, it covers crystal directions and planes, including how to determine Miller indices to describe crystallographic planes.
Solid state chemistry- laws of crystallography- Miller indices- X ray diffraction- Bragg equation- Spectrophotometer- Determination of interplanar distance- Types of crystal
This document discusses crystallography and the repeating structures found in crystals. It explains that crystals are made up of repeating arrangements of atom groups or unit cells. This repeating pattern allows for the use of x-ray diffraction to study crystal structures. Different types of symmetry are possible in crystal lattices, including rotational symmetry and translational symmetry. Various crystal systems are classified based on their lattice parameters and angles between lattice vectors. Unit cells represent the basic repeating pattern and are defined by basis vectors.
The study of crystal geometry helps to understand the behaviour of solids and their
mechanical,
electrical,
magnetic
optical and
Metallurgical properties
The document discusses Bravais lattices and crystal structures. It defines Bravais lattices as the 14 possible arrangements of lattice points that fill space in a repeating pattern, where the environment around each point is the same. It describes the four main types of Bravais lattices: simple/primitive, body-centered, base-centered, and face-centered. It also outlines the seven crystal systems - cubic, tetragonal, orthorhombic, monoclinic, triclinic, trigonal, and hexagonal - based on the unit cell parameters of length and angles.
This document discusses crystal structures and x-ray diffraction. It defines crystalline and amorphous solids, unit cells, space lattices, and the seven crystal systems. It also explains Miller indices for identifying crystal planes and Bragg's law for x-ray diffraction, which relates the scattering angle θ, interplanar spacing d, wavelength λ, and order of reflection n. Crystals are characterized by their long-range ordered atomic arrangements, which can be analyzed using techniques like x-ray crystallography.
The document discusses different methods for describing the orientation of a crystal structure with respect to a reference frame or specimen axes. It explains that at least three parameters are needed to fully describe the three-dimensional orientation of a crystal. Pole figures are described as an incomplete method that only provides information about a single crystal direction. Direct description of orientation using crystal and specimen coordinate systems and a rotation matrix relating the two is presented as a more complete method. The key steps of defining the coordinate systems, establishing the rotation relation between them, and extracting Miller
The crystal structure of a material determines its X-ray diffraction pattern. Quartz and cristobalite, two forms of SiO2, have different crystal structures and thus produce different diffraction patterns, even though they are chemically identical. Amorphous glass does not have long-range atomic order and so produces a broad diffraction peak rather than distinct peaks. The positions and intensities of peaks in a diffraction pattern provide information about a material's crystal structure, including the arrangement of atoms in the unit cell and the distances between planes of atoms.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
The document discusses crystal classes and systems. It states that crystals can be grouped into 32 classes based on their symmetry, and these classes can further be organized into six crystal systems based on their crystallographic axes. The six systems are isometric, tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic. The isometric system is described in more detail, including its defining features of equal length axes at right angles, five symmetry classes, common forms that develop like the cube and octahedron, and example minerals like galena and pyrite.
This document discusses crystallographic symmetry and classification. It defines common symmetry operations like reflection, rotation, inversion, and rotoinversion. It provides examples of symmetry notation for different crystal systems. Crystals are classified into six crystal systems and 32 crystal classes based on their unique combinations of symmetry operations and axes. Miller indices are used to describe crystal planes and forms.
This document discusses crystallographic symmetry and classification. It defines common symmetry operations like reflection, rotation, inversion, and rotoinversion. It provides examples of symmetry notation for different crystal systems. Crystals are classified into six crystal systems and 32 crystal classes based on their unique combinations of symmetry operations and axes. Miller indices are used to describe crystal planes and forms.
Structure of Crystal Lattice - K Adithi PrabhuBebeto G
The document discusses the structure of crystal lattices. It begins by defining a crystal as a solid whose constituents are arranged in a highly ordered microscopic structure called a crystal lattice. There are seven basic crystal systems based on symmetry elements. The document then discusses various types of unit cells including primitive and centered unit cells. It describes the 14 Bravais lattices and provides examples of body centered cubic, face centered cubic, and end centered cubic lattices. Finally, it summarizes the structures of sodium chloride and calcium fluoride crystals including their chemical formulas and coordination numbers.
This document discusses crystallography and crystal structure. It defines key terms like crystalline solids, amorphous solids, unit cell, crystal lattice, crystallographic planes, and Miller indices. It describes the seven crystal systems (cubic, tetragonal, orthorhombic, monoclinic, triclinic, hexagonal, trigonal) based on their symmetry characteristics. It also discusses crystal forms, symmetry operations like rotation axes and planes of symmetry, and the notation used to describe crystal planes and orientations.
There are six crystal systems based on the symmetry of the unit cell: triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. Each system has a specific set of characteristics for the lengths of the cell axes (a, b, c) and angles between them (α, β, γ). There are 14 possible arrangements, called Bravais lattices, for the positioning of lattice points within the unit cells of each system. The cubic system has the highest symmetry while triclinic has the lowest.
Crystal symmetry is defined by repeated patterns of atoms in a crystal structure. There are different types of symmetry operations including planes of symmetry, axes of symmetry, and centers of symmetry. Planes of symmetry divide the crystal into mirror images, axes of symmetry involve rotational symmetry, and centers of symmetry involve equidistance from a point. The six main crystal systems are defined by their unique combinations of symmetry elements and are classified from highest to lowest symmetry as isometric, tetragonal, orthorhombic, hexagonal, monoclinic, and triclinic. Miller indices and Weiss parameters are used to describe the orientation of crystal planes.
This document provides an introduction to crystallography. It defines crystallography as the study of crystals, which are solid substances with regular internal structures bounded by flat planar faces. The document outlines the key elements of crystals, including crystallographic axes, axial angles, crystal systems, symmetry elements, Miller indices, and habits. It also briefly discusses atomic structure, chemical bonding, and polymorphism as relevant concepts in crystallography.
This document provides an overview of crystallography. It defines key terms like crystalline solids, unit cell, space lattice, and basis. Crystalline solids have long-range order of atoms while amorphous solids do not. There are 7 crystal systems based on lattice parameters. Miller indices (hkl) are used to describe planes in a crystal lattice. Bragg's law relates the wavelength of X-rays to the diffraction pattern produced by the crystal structure. Common defects in crystal structures are discussed like vacancies, interstitials, and Frenkel and Schottky defects. Methods for determining crystal structures include X-ray crystallography and powder diffraction.
The document discusses crystal structure and X-ray diffraction. It defines crystalline and amorphous solids, and provides examples of each. Crystalline solids have an orderly repeating pattern of atoms extending in three dimensions, while amorphous solids have short-range order only. The document also discusses crystal properties, space lattices, unit cells, Bravais lattices, coordination numbers, atomic packing factors, and the seven crystal systems. Finally, it covers crystal directions and planes, including how to determine Miller indices to describe crystallographic planes.
Solid state chemistry- laws of crystallography- Miller indices- X ray diffraction- Bragg equation- Spectrophotometer- Determination of interplanar distance- Types of crystal
This document discusses crystallography and the repeating structures found in crystals. It explains that crystals are made up of repeating arrangements of atom groups or unit cells. This repeating pattern allows for the use of x-ray diffraction to study crystal structures. Different types of symmetry are possible in crystal lattices, including rotational symmetry and translational symmetry. Various crystal systems are classified based on their lattice parameters and angles between lattice vectors. Unit cells represent the basic repeating pattern and are defined by basis vectors.
The study of crystal geometry helps to understand the behaviour of solids and their
mechanical,
electrical,
magnetic
optical and
Metallurgical properties
The document discusses Bravais lattices and crystal structures. It defines Bravais lattices as the 14 possible arrangements of lattice points that fill space in a repeating pattern, where the environment around each point is the same. It describes the four main types of Bravais lattices: simple/primitive, body-centered, base-centered, and face-centered. It also outlines the seven crystal systems - cubic, tetragonal, orthorhombic, monoclinic, triclinic, trigonal, and hexagonal - based on the unit cell parameters of length and angles.
This document discusses crystal structures and x-ray diffraction. It defines crystalline and amorphous solids, unit cells, space lattices, and the seven crystal systems. It also explains Miller indices for identifying crystal planes and Bragg's law for x-ray diffraction, which relates the scattering angle θ, interplanar spacing d, wavelength λ, and order of reflection n. Crystals are characterized by their long-range ordered atomic arrangements, which can be analyzed using techniques like x-ray crystallography.
The document discusses different methods for describing the orientation of a crystal structure with respect to a reference frame or specimen axes. It explains that at least three parameters are needed to fully describe the three-dimensional orientation of a crystal. Pole figures are described as an incomplete method that only provides information about a single crystal direction. Direct description of orientation using crystal and specimen coordinate systems and a rotation matrix relating the two is presented as a more complete method. The key steps of defining the coordinate systems, establishing the rotation relation between them, and extracting Miller
The crystal structure of a material determines its X-ray diffraction pattern. Quartz and cristobalite, two forms of SiO2, have different crystal structures and thus produce different diffraction patterns, even though they are chemically identical. Amorphous glass does not have long-range atomic order and so produces a broad diffraction peak rather than distinct peaks. The positions and intensities of peaks in a diffraction pattern provide information about a material's crystal structure, including the arrangement of atoms in the unit cell and the distances between planes of atoms.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
1. Crystal Symmetry
Crystal Symmetry
The external shape of a crystal reflects the
The external shape of a crystal reflects the
presence or absence of translation-free
symmetry elements in its unit cell.
y y
While not always immediately obvious, in
While not always immediately obvious, in
most well formed crystal shapes, axis of
rotation, axis of rotoinversion, center of
, ,
symmetry, and mirror planes can be
spotted.
2. All di d i b bi d b h
All discussed operations may be combined, but the
number of (i.e. unique) combinations is limited,
to 32 Each of these is known as a point group
to 32. Each of these is known as a point group,
or crystal class.
The crystal classes may be sub-divided into one of
6 crystal systems
6 crystal systems.
Space groups are a combination of the 3D lattice
Space groups are a combination of the 3D lattice
types and the point groups (total of 65).
3. Each of the 32 crystal classes is unique to one
of the 6 crystal systems:
Triclinic, monoclinic, orthorhombic, tetragonal,
hexagonal and isometric (cubic)
hexagonal and isometric (cubic)
Interestingly, while all mirror planes and poles
Interestingly, while all mirror planes and poles
of rotation must intersect at one point, this
point may not be a center of symmetry (i).
point may not be a center of symmetry (i).
4. Crystallographic Axes
y g p
The identification of specific symmetry operations
enables one to orientate a crystal according to
an imaginary set of reference lines known as the
t ll hi
crystallographic axes.
ff f
These are distinct and different from the classic
Cartesian Axes, x, y and z, used in other
common day usage such as plotting graphs
common day usage, such as plotting graphs.
5. With the exception of the hexagonal system, the
axes are designated a b and c
axes are designated a, b, and c.
The ends of each axes are designated + or - This
The ends of each axes are designated + or -. This
is important for the derivation of Miller Indices.
The angles between the positive ends of the axes
are designated α, β, and γ.
α lies between b and c.
β lies between a and c.
γ lies between a and b.
6. Quantities can also be applied to further describe
vectors and planes relative to a b and c
vectors and planes relative to a, b, and c
These are u, v, w:
u: projection along a
v: projection along b
p j g
w: projection along c
7. Quantities can also be applied to further describe
vectors and planes relative to a b and c
vectors and planes relative to a, b, and c
These are h, k, l:
h: information relative to a axis
v: information relative to b axis
w: information relative to c axis
[ ] ith (hkl)
[uvw] with (hkl)
(hkl) f b
(hkl) faces on a cube
8. Axial Ratios
With the exception of the cubic (isometric) system,
h ll h d ff l h
there are crystallographic axes differing in length.
I i i l it ll d i th
Imagine one single unit cell and measuring the
lengths of the a, b, and c axes.
To obtain the axial ratios we normalise to the b axis.
These ratios are relative.
9. Unique crystallographic axes of the 6
crystal systems
crystal systems
Triclinic: Three unequal axes with oblique angles.
Monoclinic: Three unequal axes, two are inclined to
one another, the third is perpendicular.
Orthorhombic: Three mutually perpendicular axes of
different lengths.
Tetragonal: Three mutually perpendicular axes, two
are equal, the third (vertical) is shorter.
Hexagonal: Three equal horizontal axes (a1, a2, a3)
and a 4th perpendicular (vertical) of different length.
Cubic: Three perpendicular axes of equal length.
10. Triclinic: Three unequal axes with oblique
angles.
angles.
• To orientate a triclinic crystal
the most p ono nced one
the most pronounced zone
should be vertical.
c
• a and b are determined by
the intersections of (010) and
(100) ith (001)
b
(100) with (001).
• The b axis should be longer
a
• The b axis should be longer
than the a axis.
11. The unique symmetry operation in a triclinic
The unique symmetry operation in a triclinic
system is a 1-fold axis of rotoinversion(equivalent
to a center of symmetry or inversion, i).
to a center of symmetry or inversion, i).
All forms are pinacoids – therefore must consist of
p
two identical and parallel faces.
Common triclinic rock-forming minerals include
microcline, some plagioclases, and wollastonite.
12. Monoclinic: Three unequal axes, two are
inclined with oblique angles, the third is
perpendicular.
O i t ti f t l h
• Orientation of a crystal has
few constraints – b is the
only axis fixed by
t
c
symmetry.
• c is typically chosen on the
basis of habit and b
cleavage.
• α and γ = 90 °.
• There are some very rare
• There are some very rare
cases where b equals 90°
giving a pseudo-
orthorhombic form
a
orthorhombic form.
13. The unique symmetry operation in a monoclinic
The unique symmetry operation in a monoclinic
system is 2/m – a twofold axis of rotation with a
mirror plane.
b is the rotation, while a and c lie in the mirror
l
plane.
Monoclinic crystals have two forms: pinacoids and
Monoclinic crystals have two forms: pinacoids and
prisms.
Common monoclinic rock-forming minerals include
clinopyroxene, mica, orthoclase and titanite.
14. Orthorhombic: Three mutually
perpendicular axes of different
perpendicular axes of different
lengths.
• Convention has it that a crystal is
oriented such that c > b > a.
c
• Crystals are oriented so that c is
parallel to crystal elongation.
• In this case the length of the b axis
a
• In this case the length of the b axis
is taken as unity and ratios are
calculated thereafter.
b
15. The unique symmetry operation in an orthorhombic system is
The unique symmetry operation in an orthorhombic system is
2/m 2/m 2/m – Three twofold axis of rotation coinciding with
the three crystallographic axes.
Perpendicular to each of the axes is a mirror plane.
The general class for the orthorhombic system are rhombic
dipyramid {hkl}.
There are three types of form in the class: pinacoids, prisms,
and dipyramids.
Common orthorhombic rock-forming minerals include andalusite
and sillimanite, orthopyroxene, olivine and topaz.
16. Tetragonal: Three mutually perpendicular
axes, two are equal, the third (vertical) is
shorter.
• The two horizontal axis in a
tetragronal mineral are oriented in
the plane of the horizontal
c
the plane of the horizontal.
Therefore, if a = b, c must be in
the vertical. a2
• There is no rule as to whether c is
greater or less than a
greater or less than a.
a1
17. The unique symmetry operation in a tetragonal system is 4/m 2/m
2/m – The vertical axis (c) is always a fourfold axis of rotation
2/m – The vertical axis (c) is always a fourfold axis of rotation.
There are 4 two-fold axis of rotation: 2 parallel to the
crystallographic axes a and b the others at 45°
crystallographic axes a and b, the others at 45 .
There are 5 mirror planes.
The general class for the orthorhombic system is known as the
ditetragonal-dipyramidal class.
There are four types of form in the class: basal pinacoids,
tetragonal prisms, tetragonal dipyramids, and ditetragonal
prisms.
Common tetragonal rock-forming minerals include zircon, rutile and
anatase, and apophyllite.
18. Hexagonal: Three equal horizontal axes (a1, a2, a3)
and a 4th perpendicular vertical axis of different
length.
• The three horizontal axis of a
he agonal mine al a e o iented in
c
hexagonal mineral are oriented in
the plane of the horizontal, with c
in the vertical.
• Unlike the other systems the
B i Mill l t f
a3
Bravais-Miller nomenclature for
crystal faces is given by 4 numbers
(i.e. {0001})
a2
• The first three numbers are listed
in order of a1, a2, a3. a1
90°
= = 90°
= 120°
19. The unique symmetry operation in the hexagonal system is a six-
fold axis of rotation, and the most common space group is 6/m
, p g p
2/m 2/m.
There vertical axis is the six-fold rotational operation, while there
f th 6 t f ld i f t ti i th h i t l l (3
are a further 6 two-fold axis of rotation in the horizontal plane (3
coincide with the an axes).
There are 7 mirror planes
There are 7 mirror planes.
The general class for the orthorhombic system is known as the
dihexagonal-dipyramidal class
dihexagonal-dipyramidal class.
There are five types of form in the class: pinacoids, hexagonal
prisms hexagonal dipyramids dihexagonal prisms and
prisms, hexagonal dipyramids, dihexagonal prisms, and
dihexagonal dipyramids.
Common hexagonal minerals include beryl and apatite.
Common hexagonal minerals include beryl and apatite.
20. Isometric (cubic): Three equal length axes that
intersecting at right-angles to one another
intersecting at right angles to one another.
• The axes are indistinguishable, as
a e the inte secting angles As
are the intersecting angles. As
such all are interchangable.
a3
• There are 15 isometric forms, but
the most common are: a2
3
– Cube
– Octahedron
– Dodecahedron
a1
– Tetrahexahedron
– Trapezohedron
– Trisoctahedron
Trisoctahedron
– Hexoctahedron
= = = 90°