Crystal Cube Research Articles

Ghosts in the glass: the rise and fall of Victorian autostereoscopic photography

ABSTRACT This essay tells the story of the invention and disappearance of the crystal cube miniature, the first practicable form of autostereoscopic photography. When the British engraver and studio photographer Henry Swan unveiled his patented invention at the September 1863 meeting of the British Association for the Advancement of Science, there was every reason to expect he had a commercial success on his hands. These hand-colored photographs encased in glass and endowed with a startling illusion of depth and relief spoke to the appetites for realism, technological novelty, and tactility in mid-nineteenth-century British visual culture. So why did the crystal cube miniature disappear by the end of the decade and find itself erased from public memory by the end of the century? Why have most scholars of Victorian visual culture never heard of the crystal cube miniature? Through a close analysis of a single example of the medium, ‘Portrait of Sarah Bennett’ (ca. 1862) that situates this object in a media archaeology of 1860s visual technologies of portraiture and stereoscopy, I attribute the crystal cube miniature’s commercial failure to its layered effects of verisimilitude and spectrality, which disrupted Victorian conventions of pictorial and optical spectatorship.

High strain-rate strength response of single crystal tantalum through in-situ hole closure imaging experiments

The properties of crystalline materials often depend on directionality and operating conditions. Specifically, the strength of materials can depend anisotropically on crystal direction and the loading condition. To probe these effects, a preliminary series of high strain-rate (>105/s) strength plate-impact hole closure experiments were performed on high purity single crystal tantalum cubes. The orientation of the single crystals with respect to impact/loading were varied to provide data to inform crystal plasticity modeling efforts. The experiments consist of in-situ high-resolution X-ray radiographic imaging of the hole collapse under dynamic compression conditions to infer the material strength via its resistance to closure at increasing levels of plastic strain. The experiments are compared against hydrocode simulation predictions. A comparison with simple elastic perfectly plastic strength model predictions is presented to elucidate the response of the different crystal orientations at high strain-rate and large plastic strains.

Modulation of the Intrinsic Radical Scavenging Properties of CeO2 Nanoparticles

Cerium dioxide (CeO2) has been extensively investigated as a scavenger of reactive oxygen radicals, particularly in the context of polymer electrolyte membrane fuel cells. This study focuses on elucidating the impact of exposed crystal facets of CeO2 nanoparticles on their radical scavenging activities. The manipulation of crystal shapes, including rod, cube, and octahedral forms, allows for controlled variation of the exposed crystal facets of CeO2 NPs. Characterization of the resulting CeO2 NPs is conducted using XRD, Raman spectroscopy, XPS, BET, and Fenton’s reaction. The research reveals that the intrinsic radical scavenging activity of CeO2 NPs can be effectively modulated by controlling their exposed crystal facets.

Promoted oxygen adsorption on porous CeO2 cubes with abundant oxygen vacancies for efficient gaseous formaldehyde removal

Photocatalytic degradation stands as a promising method for eliminating gas-phase pollutants, with the efficiency largely hinging on the capture of photogenerated electrons by oxygen. In this work, we synthesized a porous CeO2 single crystal cube with abundant oxygen vacancies as photocatalyst, employing urea as a pore-forming agent and for gas-phase formaldehyde degradation. Compared with the CeO2 cubes without pores, the porous ones were superior in specific surface area, akin to conventional CeO2 nanoparticles. The photocatalytic degradation for gas-phase formaldehyde on porous CeO2 cubes was significantly accelerated, of which degradation rate is 3.3 times and 2.1 times that of CeO2 cubes without pores and CeO2 nanoparticles, respectively. Photoelectric tests and DFT calculations revealed that this enhancement stemmed from facilitated oxygen adsorption due to pronounced oxygen vacancies. Consequently, the capture of photoelectrons by oxygen was promoted and its recombination with holes was suppressed, along with an accelerated generation of curial free radicals such as ·OH. This work reveals the pivotal role of surface oxygen vacancies in promoting adsorbed oxygen, proposing a viable strategy to enhance the photocatalytic degradation efficiency for gas-phase pollutants.

Exclusive Coordination between Melem and Silver(I) Ions: From Irregular Aggregates to Nanofibers to Crystal Cubes.

There is growing focus on metal-free molecules and polymers owing to their potential applications in various energy and catalysis-related applications. Melem (2,5,8-triamino-s-heptazine, C6H6N10) has emerged as a metal-free material for solar-to-fuel conversion. However, its reactivity with metal ions or organic molecules has never been reported although it possesses multiple supramolecular interaction sites. In this work, we report on the synthesis of a novel metal-organic coordination framework (melem-Ag) by simply introducing Ag+ into the aqueous suspension of aggregated melem particles. Notably, as the reaction progresses, the melem disappears, and the morphology of the newly formed complex spontaneously evolves from nanofibers to single-crystalline blocks, which possess the same chemical structure, indicating that the morphology evolution is driven by Ostwald ripening. The structure of melem-Ag displays infinite nanocages of triangular pyramids consisting of melem molecules and Ag+, linked via Ag-N coordinate bonding and Ag-Ag argentophilic interactions. It is noteworthy that Ag+ is the only transition-metal cation that reacts with melem suspensions, even in the presence of other transition-metal cations (Co2+, Ni2+, Cu2+, and Zn2+). The coordination of Ag+ to melem results in metal-to-ligand charge transfer (MLCT), resulting in a quenched photoluminescence and enhanced light absorption. Exposing the melem-Ag crystals to UV light for varying time intervals results in the formation of colorful powders, which may be used for Ag-decorated photocatalysts.

High-resolution light-field particle imaging velocimetry with color-and-depth encoded illumination

Three-dimensional and three-components (3D-3C) measurement of flow velocity vector is important for the investigation of mechanism underlying flow structure. Light-field particle imaging velocimetry (LF-PIV) is a newly emerged technique for flow velocity measurement. However, LF-PIV suffers low axial resolution, prohibiting it for high fidelity imaging. To overcome this limitation, we proposed to employ color-depth-encoded illumination in light-field PIV (Code LF-PIV) to refine the particle's axial location with the color-depth information of the illumination beam. Code LF-PIV is the first system that integrates the snapshot acquisition of light-field acquisition and the high resolution capability of color coded illumination. Compared to conventional light-field PIV, Code LF-PIV can achieve much higher axial resolution due to the new illumination strategy. Compared to traditional coded illumination PIV, such as Rainbow PIV, Code LF-PIV has higher flexibility for variant imaging applications because of the elimination of customized diffractive optical element. We demonstrated the superiority of our system by imaging fixed particle, randomly distributed cavities inside crystal cube, and the square lid-driven cavity flow, where our Code LF system has increased the axial resolution by a factor of 23 when compared to the conventional LF system, and has achieved a comparable axial resolution as the depth super-resolved Rainbow PIV. Comprehensive evaluation of the imaging results demonstrated that Code LF-PIV combines the advantages of the high resolution of color-depth coded method with the convenient volumetric imaging of light-field camera, making Code LF-PIV a useful technique for high-resolution and large-scale flow measurement.

Chilling Effects: Assessing Chlorine Levels in Hawker-Served Crystal Ice Cubes in Banjarbaru City

Cold drinks served will be served along with ice cubes, one of which is crystal ice cubes. In making ice cubes must have the same quality requirements as drinking water. The provision of water quality that is suitable for drinking needs to be examined. As for drinking water quality requirements according to the Regulation of the Minister of Health of the Republic of Indonesia Number 2 of 2023 concerning drinking water quality requirements, the presence of free chlorine compounds in the allowed network distribution is 0.2-0.5 mg/l. Chlorine serves to inhibit growth and eradicate bacteria from various types of microbes, but if chlorine exceeds quality standards and reacts with water it can form hypochlorous acid which can damage cells in the body and can cause digestive disorders because it can make the stomach wall erosion and cause ulcer disease and if used in the long term can cause kidney disease and cancer. This research aims to analyze chlorine levels and crystal ice cubes of hawker sellers in Banjarbaru City and the factors that influence it. The results of the study explained that from 28 samples of crystal ice cubes, only 2 (7%) samples of crystal ice cubes met the standards, while the other 26 samples (93%) had chlorine levels above the maximum limit of 0.5 mg / L. While the behavior of ice cube sellers in washing hands before taking ice cubes only 11 people (39%), 17 other beverage sellers (61%) did not wash their hands before taking ice cubes.

Crystal Cube: Forecasting Disruptive Events

ABSTRACT Disruptive events within a country can have global repercussions, creating a need for the anticipation and planning of these events. Crystal Cube (CC) is a novel approach to forecasting disruptive political events at least one month into the future. The system uses a recurrent neural network and a novel measure of event similarity between past and current events. We also introduce the innovative Thermometer of Irregular Leadership Change (ILC). We present an evaluation of CC in predicting ILC for 167 countries and show promising results in forecasting events one to twelve months in advance. We compare CC results with results using a random forest as well as previous work.

Spherical Gaussians: An intuitive method for creating complex anisotropies in interface energies for the phase field method

The Phase Field Method requires continuous functions to control interface energies between phases. We have developed a method for phase field modeling where interface energies are described by spherical gaussians, a set of continuous functions which can simulate a wide variety of complex anisotropies. We demonstrate the use of the technique to produce a wide array of crystal geometries, including rods, hexagonal rods, cubes, and cubic dendrites, using the native properties of spherical gaussians to create specific interface energies throughout the full solid angle of an energy surface. Parameters controlling the sharpness of minima are shown to have a significant effect on morphology.

Radon measurements with a compact, organic-scintillator-based alpha/beta spectrometer

We have developed a compact, organic-scintillator-based alpha/beta spectrometer for radon measurements and have characterized it using a unique, small radon chamber. The spectrometer is composed of a through-silicon via (TSV) silicon photomultiplier (or SiPM) and a 6 mm × 6 mm × 6 mm stilbene crystal cube. Analog signals from the SiPM are sent to a digitizer. The detector is housed in a light-tight box, with a stacked air filter installed in one side of the box to enable 222Rn gas to diffuse to the inside. We conducted one experiment with the spectrometer and an AlphaGUARD detector placed in a basement at the University of Michigan, and we conducted other experiments with both detectors placed in a small radon chamber together with 226Ra sources. By applying a pulse-shape-discrimination technique, we were able to separate the alpha and beta spectra simultaneously and clearly and to measure them quantitatively. We found two peaks in the measured alpha spectrum: a lower-energy peak due to 218Po and a higher-energy peak due to 214Po. We found a linear relation between the radon concentration y from AlphaGUARD and the counting rates x from the stilbene-SiPM detector: y (Bq/m3) = 51 x −276. The alpha/beta spectrometer is less than 10 mm thick, and we expect that it will be easy to increase the sensitivity with future device construction. Thus, this compact, organic-scintillator-based alpha/beta spectrometer shows promise for use in novel radon-detection systems.

Identifikasi Bakteri Escherichia Coli Pada Es Kristal Di Rumah Makan Kecamatan Baiturrahman - Banda Aceh

Water is the main component for producing crystal ice cubes, where the water used should fulfill the drinking water criteria that was not allowed to contain Escherichia coli. This research was conducted at the Microbiology Laboratory, AKAFARMA, Banda Aceh. This study aimed to determine the presence of contamination of Escherichia coli bacteria contained in crystal ice cubes. This research used a descriptive method. The results showed that the six samples of crystal ice cubes in the Baiturrahman District restaurant negatively contained Escherichia coli because they did not show colors that match the characteristics of Escherichia coli bacteria.

PET detectors with 127 ps CTR for the Tachyon-II time-of-flight PET scanner.

The signal-to-noise ratio (SNR) of the reconstructed image of Positron Emission Tomography (PET) can be improved by the timing measurement. In this article, we designed, fabricated and tested 32 time-of-flight (TOF) detectors for the second generation of Tachyon TOF-PET scanners. The detector module consists of two arrays of 2 × 12 lutetium-yttrium oxyorthosilicate (LYSO) crystal cubes of 6 ×6× 6 mm3. The discrete crystals were coupled to the 6 mm silicon photomultipliers (SiPMs) with optical glue. All the SiPM were tested for dark current. To correct the errors in the timing measurements caused by time-walk, two compensation methods (log-correction and linear-correction) based on the relationship between energy and timing information were purposed. As a comparison, the SiPM arrays coupled to 4 mm and 6 mm side crystal cube without optical glue were tested for coincidence timing resolution (CTR). The mean and standard deviations (SD) of dark current for the 1536 tested SiPMs were 12.72 +/- 1.70 μA at the bias voltage of 31.5 V and the temperature of 20 °C (±1 °C). CTR performance has increased by ~5% within a narrow energy window, and ~10% in a wide energy window by log-correction. The mean and SD of the CTR of 6 mm side crystal cube glue coupled was 126.9 +/- 3.6 ps for the 768 pairs of tested SiPMs. The detector is expected to provide a technical reference for the next generation of ultra-fast CTR commercial PET scanner using multilayer detectors.

A Multiscale Model to Incorporate Texture Evolution into Phenomenological Plasticity Models

Crystal plasticity is a micromechanics-based model that is regularly used to simulate plastic spin during large deformation. Although crystal plasticity can provide an accurate description of local deformation behaviour, it is often computationally expensive and usually replaced by flow rule-based phenomenological models that do not capture this phenomenon. This work presents a phenomenological-based texture evolution (PBTE) model that allows for the enhancement of flow rule-based models to capture microstructural spin in a phenomenological manner. A numerical framework is presented for generating and calibrating the microstructural evolution for the PBTE model using crystal plasticity. The PBTE Model is calibrated and employed to predict the macroscopic mechanical response and the generated microstructural spin for single crystal FCC cube during non-proportional strain paths.

Investigation of spatial resolution improvement by use of a mouth-insert detector in the helmet PET scanner

The dominant factor limiting the intrinsic spatial resolution of a positron emission tomography (PET) system is the size of the crystal elements in the detector. To increase sensitivity and achieve high spatial resolution, it is essential to use advanced depth-of-interaction (DOI) detectors and arrange them close to the subject. The DOI detectors help maintain high spatial resolution by mitigating the parallax error caused by the thickness of the scintillator near the peripheral regions of the field-of-view. As an optimal geometry for a brain PET scanner, with high sensitivity and spatial resolution, we proposed and developed the helmet-chin PET scanner using 54 four-layered DOI detectors consisting of a 16×16×4 array of GSOZ scintillator crystals with dimensions of 2.8×2.8×7.5mm3. All the detectors used in the helmet-chin PET scanner had the same spatial resolution. In this study, we conducted a feasibility study of a new add-on detector arrangement for the helmet PET scanner by replacing the chin detector with a segmented crystal cube, having high spatial resolution in all directions, which can be placed inside the mouth. The crystal cube (which we have named the mouth-insert detector) has an array of 20×20×20 LYSO crystal segments with dimensions of 1×1×1mm3. Thus, the scanner is formed by the combination of the helmet and mouth-insert detectors, and is referred to as the helmet-mouth-insert PET scanner. The results show that the helmet-mouth-insert PET scanner has comparable sensitivity and improved spatial resolution near the center of the hemisphere, compared to the helmet-chin PET scanner.

Study of linearity of LYSO crystal for the high energy cosmic radiation detection (HERD) facility

The high energy cosmic-radiation detection (HERD) facility is a space mission designed for detecting cosmic ray (CR) electrons, $$\gamma $$ -rays up to tens of TeV and CR nuclei from proton to iron up to several PeV. The main instrument of HERD is a 3-D imaging calorimeter (CALO) composed of nearly ten thousand lutetium yttrium orthosilicate (LYSO, with cerium doping) crystal cubes. A large dynamic range of single HERD CALO Cell (HCC) is necessary to achieve HERD’s PeV observation objectives, which means that the response of HCC should maintain a good linearity from minimum ionizing particle (MIP) calibration to PeV shower maximum. In order to study the linearity of HCC over such a large energy range, a beam test has been implemented at the E2 and E3 beam lines of BEPC. High intensity pulsed electron beam provided by E2 line is used for producing high energy density within HCC; $$\pi ^{+}$$ /proton provided by E3 line are used for HCC calibration. The results show that no saturation effect occurs and the linearity of HCC is better than 10% from 30 MeV (1 MIP) to $$1.1\times 10^{3}$$ TeV (energy density is 93 TeV/cm $$^{3})$$ , which can meet the requirement mentioned above.

Grouping of Mangifera indica L. Cultivars of Subang West Java by Leaves Morphology and Anatomy Characteristics

<p>The wide distribution and high species diversity produce large variation in morphology, anatomy and genetics of local mangoes. Until now, most mango classification system is based on the generative character while the vegetative character is neglected. Inventory of mango cultivars in Subang rarely studied, therefore the purpose of this study is to development foundation of identification methods basedthe anatomy and morphology of leavesof mango cultivars of Subang. The data could futher develop as baseline information about mango cultivar diversity in Indonesia. During study, 21 mango cultivars found in Subang, West Java. Leave samples were collected from the field and soaked in 70% alcohol. Leaf anatomy preparats made by whole-mount method and paraffin. The shape and type, location, size, density and index of stomata were observed. The results showed high similarity of all sampels.There are three variations of vascular tissues on petioles, letter U shape (planoconvex),U lobed (highlyconvex) and round (circular) with the type of drus crystal form, small cubes, and prismatic. All cultivars have actinositic stomata and hypostomatatic leaves. It could be concluded that density, size and stomata index are less powerful to be apply as characters to identified cultivars of mangoes however the presence of oxalate crystals can be use to the grouping mango cultivars in Subang. </p>

KUALITAS MIKROBIOLOGI ES BATU KRISTAL DAN HYGIENE SANITASI SEPANJANG RANTAI DISTRIBUSI DI SURABAYA

Crystal ice cube consumed by people is distributed through distribution chain from factories, agents, and ice traders in Surabaya. Each distribution chain posses risk of contamination to the quality of the ice, one of which is microbiological contamination that cause health problems to consumers. This is descriptive study aimed to obtain microbiological quality of crystal ice cube and hygiene sanitation throughout distribution chain in Surabaya. Sampling and observations were conducted sequentially in the same day, in different time and with 3 time repetition for 3 days in a row. Data were analyzed descriptively. The result showed that the ice crystals did not contain E. coli yet contained MPN Coliform. The rate of MPN Coliform on ice at factory was 10 colonies / 100 cc sample, at agent was 12-15 colonies / 100 cc sample, and at merchant were 15-43 colonies / 100 cc sample. Hygiene sanitation affecting MPN Coliform in crystal ice are non standard raw materials, production process, transportation, and the handlers. In conclusion, microbiological quality of crystal ice cube along the distribution chain in Surabaya with E. coli parameter did not meet standard. Health Department needs to conduct surveillance on a regular basis. Factory of ice cube needs to make Standard Operating Procedures. Agents and traders need to improve hygiene sanitation of conveyance, transport personnel, equipment, and handlers. Keywords : Ice Cube Crystals, Chain Distribution, Hygiene Sanitation, MPN Coliform, E. coli

An Oxofluoride Catalyst Comprised of Transition Metals and a Metalloid for Application in Water Oxidation.

The application of the recently discovered oxofluoride solid solution (Cox Ni1-x )3 Sb4 O6 F6 as a catalyst for water oxidation is demonstrated. The phase exhibits a cubic arrangement of the active metal that forms oxo bridges to the metalloid with possible catalytic participation. The Co3 Sb4 O6 F6 compound proved to be capable of catalyzing 2H2 O→O2 +4H(+) +4e(-) at 0.33 V electrochemical and ≤0.39 V chemical overpotential with a TOF of 4.4⋅10(-3) , whereas Ni3 Sb4 O6 F6 needs a higher overpotential. Relatively large crystal cubes (0.3-0.5 mm) are easily synthesized and readily handled as they demonstrate both chemical resistance to wear after repeated in situ tests under experimental conditions, and have a mechanical hardness of 270 V0.1 using Vickers indentation. The combined properties of this compound offer a potential technical advantage for incorporation to a catalytic interface in future sustainable fuel production.

Precision timing measurements for high energy photons

Particle colliders operating at high luminosities present challenging environments for high energy physics event reconstruction and analysis. We discuss how timing information, with a precision on the order of 10ps, can aid in the reconstruction of physics events under such conditions. We present calorimeter based timing measurements from test beam experiments in which we explore the ultimate timing precision achievable for high energy photons or electrons of 10GeV and above. Using a prototype calorimeter consisting of a 1.7×1.7×1.7cm3 lutetium–yttrium oxyortho-silicate (LYSO) crystal cube, read out by micro-channel plate photomultipliers, we demonstrate a time resolution of 33.5±2.1ps for an incoming beam energy of 32GeV. In a second measurement, using a 2.5×2.5×20cm3 LYSO crystal placed perpendicularly to the electron beam, we achieve a time resolution of 59±11ps using a beam energy of 4GeV. We also present timing measurements made using a shashlik-style calorimeter cell made of LYSO and tungsten plates, and demonstrate that the apparatus achieves a time resolution of 54±5ps for an incoming beam energy of 32GeV.

Significant enhancement of the critical current density for cubic BN addition into ex situ spark plasma sintered MgB2

High density (above 93%) superconducting bulks of MgB2 with addition of hexagonal BN (h-BN) and cubic BN (c-BN) with compositions ((MgB2) + (BN)x, x = 0.01, 0.03, 0.05) were obtained by ex situ spark plasma sintering. All the investigated samples have the critical temperature Tc = 38.8 K. The variation of the critical current density Jc with the external magnetic field H for h-BN added sample is almost overlapping the Jc(H) dependence for the pristine MgB2 sample. On the other hand, Jc for the samples added with c-BN is larger at high magnetic fields, while the decrease of Jc at low H is very small. At T = 20 K, a Jc of 102 A cm−2 is determined for the sample with xc-BN = 0.005 at H = 58 kOe, and for the sample with xc-BN = 0.01 at 54 kOe. Magnetic relaxation measurements indicate a significant flux pinning enhancement in MgB2 samples added with c-BN. It is proposed that the disorder at the interface caused by the convenient lattice matching relationship between the lateral plane of the MgB2 crystal prism and the face of the c-BN crystal cube is responsible for the observed vortex pinning increase.