Crystal Diameter Research Articles

Effects of high voltage electrostatic field assisted freezing enhanced with ultrahigh permittivity ceramic on quality attributes of grass carp (Ctenopharyngodon idella) fillets during frozen storage

Small sample capacity is a critical limitation for the industrialization of the high voltage electrostatic field assisted freezing (HVEFF) technique. In this study, using grass carp as a sample, the effects of ultrahigh permittivity ceramic enhanced HVEFF system on the quality attributes of grass carp (Ctenopharyngodon idella) fillets during freezing and frozen storage were investigated. The appropriate electrostatic field strength for freezing grass carp fillets was determined first with the HVEFF Peltier cooling platform and then used for the freezing and frozen storage of grass carp fillets in an HVEFF refrigerator at −18 °C. The biochemical qualities, and ice crystal morphology of the samples were measured every 2, 4, 6, and 8 weeks during frozen storage. Compared to the frozen control, this novel HVEFF system could effectively delay the deterioration of texture and water migration, and reduce TVB-N, TBARS and the equivalent ice crystal diameters. This study not only showed the positive effect of this novel HVEEF system on the frozen preservation of grass carp fillets but more importantly provided a solution to the bottleneck of HVEFF industrialization.

Effects of sequential combination of cryogenic immersion freezing and ultra-cold frozen storage on the quality of Korean white kimchi

This study aimed to assess the effects of three different freezing techniques — cold room freezing (CRF; −20 °C), air-blast freezing (ABF; −70 °C), and cryogenic immersion freezing (CIF; −70 °C) — on the microstructure and physicochemical properties of Korean white kimchi (KWK) during frozen storage at −20 °C and − 45 °C for 8 weeks. CIF-treated KWK exhibited a higher freezing rate and after ultra-cold (UC; −45 °C) frozen storage, it showed a greater number and smaller diameter and area of ice crystals than CRF- and ABF-treated KWK. Drip loss was reduced and CIE color changes were delayed in KWK under UC frozen storage. The pH, titratable acidity, and reducing sugar content of frozen KWK remained unaffected by the freezing method, storage temperature, or duration. Thus, CIF combined with UC frozen storage preserves the physicochemical quality of KWK with minimal histological damage during long-term storage. Industrial relevanceIn the kimchi industry, where the shelf life of commercial products is often constrained by successive fermentation under low-temperature storage and distribution conditions, introducing frozen kimchi is a promising solution to reduce waste of overripe kimchi in the supply chain. This study highlights the effectiveness of combining CIF and UC frozen storage methods to minimize the damage caused by freezing in kimchi. This innovative technology provides a practical means for streamlining freezing processes, saving operational time, and ensuring kimchi quality during long-term storage and distribution.

Advance Heteroatom Dopants Nitrogen, Boron, Sulphur and Phosphorus on Carbon Dots Towards Histamine Detection in Fish Sample

This study introduces heteroatom-doped carbon dots (CDs), namely boron-sulphur (BS-CDs) and nitrogen-phosphorus (NP-CDs), highlighting their potential as optical materials for sensitive histamine detection in sensor applications. Synthesized through facile pyrolysis of citric acid cores with non-metal dopants, resulting in confirmed graphene-like structures and uniform spheres with crystal diameters below 3 nm of BS-CDs and NP-CDs. The optical properties exhibited blue fluorescence, with emission wavelengths of 280 nm (QY 0.08%) and 420 nm (QY 1.72%) for BS-CDs and NP-CDs, respectively. Despite declined fluorescence intensities due to interfering components, both CDs demonstrated low selectivity for histamine, which increased the intensity in its presence. Notably, BS-CDs exhibited superior detectability of histamine at a low concentration of 26.3 ppm compared to 42.8 ppm for NP-CDs. Cytotoxicity studies indicated low toxicity for both CDs, positioning them as promising candidates for further development as histamine detectors

A Soft Measurement Method for the Tail Diameter in the Growing Process of Czochralski Silicon Single Crystals

In the Czochralski silicon single crystal growth process, the tail diameter is a key parameter that cannot be directly measured. In this paper, we propose a real-time soft measurement method that combines a deep belief network (DBN) and a support vector regression (SVR) network based on system identification to accurately predict the crystal diameter. The main steps of the proposed method are as follows: First, we address the delay problem of the effects of the temperature and crystal pulling speed on the tail diameter growth by using a back propagation (BP) neural network based on the mean impact value (MIV) method to determine the optimal delay time. Second, we construct a prediction model of the tail diameter by using the DBN network with the temperature and crystal pulling speed as input variables in the crystal growth process. Third, we improve the DBN network by using the SVR network to enhance its linear regression capability. We also employ the ant colony optimization (ACO) algorithm to obtain the optimal parameters of the SVR network. Finally, we compare the performance of the DBN-ACO-SVR network based on system identification with the DBN and SVR networks, and the results show that our method can effectively deal with the delay problem and achieve the accurate prediction of the tail diameter in the Czochralski silicon single crystal growth process.

Effects of Surface Size and Shape of Evaporation Area on SiC Single-Crystal Growth Using the PVT Method

Silicon carbide (SiC) polycrystalline powder. As the raw material for SiC single-crystal growth through the physical vapor transport (PVT) method, its surface size and shape have a great influence on growth of crystal. The surface size and shape of the evaporation area filled with polycrystalline powder were investigated by numerical simulation in this study. Firstly, the temperature distribution and deposition rate distribution for the PVT system were calculated by global numerical simulation, and the optimal ratio of polycrystalline powder surface diameter to seed crystal diameter was determined to be 1.6. Secondly, the surface of the evaporation area filled with polycrystalline powder was covered by a graphite ring and a graphite disc, respectively, to change its surface shape. The results show that adjusting the surface size and shape of the evaporation area filled with polycrystalline powder is an effective method to control the growth rate, growth stability, and growth surface shape of the single crystal. Finally, the result obtained by selecting appropriate covered structures for actual growth indicates that this process can act as a reference for improving the quality of single crystals.

Preparation and Morphology Control of Hydroxyapatite by Aqueous Precipitation

Hydroxyapatite, with excellent biocompatibility, biological activity, and biological affinity, is the main inorganic component of human bones and teeth. It can promote bone tissue regeneration and has important applications in bone tissue engineering fields such as bone defect repair and bone replacement. In this study, calcium acetate solution and diammonium dihydrogen phosphate solution had been mixed to prepare calcium phosphate through aqueous precipitation reaction. The testing results of scanning electron microscopy and X-ray diffraction show that the morphology of the product can be controlled by changing the pH, the temperature, and the method of adding reactant solution dropwise. When the temperature of the reaction system is 20℃, plate-like calcium hydrogen phosphate is mainly obtained; block-like hydroxyapatite is obtained when the temperature rised to 40℃; and needle shaped hydroxyapatite is obtained at 60℃. The length and diameter of two-dimensional hydroxyapatite crystals become smaller when the temperature and the pH value of the reaction system increase.

Improvement of the resistivity uniformity of 8-inch 4H–SiC wafers by optimizing the thermal field

8-inch N-type 4H–SiC single crystals were grown on 4° off-axis seeds by the physical vapor transport (PVT) method. The electrical properties of 8-inch 4H–SiC wafers were assessed by contactless resistivity mapping. The resistivity of the whole wafer is inhomogeneous with an inhomogeneity of 4.8 %, much higher than that of standard 6-inch wafers with a resistivity inhomogeneity of 1.2 %. This nonuniformity phenomenon is attributed to facet formation caused by discontinuities in the thermal field as the crystal diameter increases. Due to the facet effect, the nitrogen doping concentration in the facet region is higher than that in other regions. By optimizing the thermal field through adjustment of the growth conditions, a nearly flat and slightly convex 8-inch SiC crystal growth interface was obtained. The uniformity of the resistivity of 8-inch SiC wafers is significantly improved, with an inhomogeneity of 1.6 %.

Characterization of Kinetics-Controlled Morphologies in the Growth of Silver Crystals from a Primary Lead Melt

Silver, a precious metal, can be recovered as a by-product of the processing of non-ferrous metals such as lead. In this work, silver crystals grown from the controlled cooling of a 10% silver–90% lead melt have been examined to quantify crystal morphologies developed under industrial conditions. X-ray tomography (XCT) is adapted to quantify the size and morphology of silver crystal structures grown from the Ag-Pb melt. The examination utilized high X-ray energies and small sample sizes to mitigate attenuation and enhance image quality. Examination of single crystal dendrites under high magnification demonstrates that silver crystals, even those grown under commercial conditions, yield a Face-Centered Cubic (FCC) crystalline lattice, which could be important for the practical extension of this work to the commercial production of Ag nano-crystals and crystalline supra-molecular structures. The crystals observed are composed of multiple twinned euhedral grains in a variety of dendritic to acicular arrangements, yielding a substantial heterogeneity of crystalline forms. XCT data were used to generate size and shape descriptors for the individual crystals. The results were compared to an equivalent set of descriptors generated from laser sizing examination of a sample of unconsolidated crystals from the same experimental run. The correspondence to within 9% of the crystal equivalent diameters determined independently by the XCT and laser sizing demonstrates a favorable outcome in particle sizing as achieved by visual inspection of XCT results. XCT examination of crystal assemblages identifies small octahedral crystals and larger triangular platelets. The structures expected for FCC crystals grown at thermodynamically controlled conditions are not observed in our systems, suggesting the possibility of the first crystal nuclei form at such conditions, but their growth transition to kinetically controlled mechanisms occurs as their size increases above a threshold cutoff. Based on literature observations, this size threshold is much smaller than the resolution of the XCT instrumentation employed herein. Our characterization data are in fact consistent with thermodynamics/kinetics—and then kinetics-controlled mechanisms—as the crystal size increases. This observation is important because the systems considered here are representative of commercial processes. As such, this work extends prior crystal growth concepts, which were explored in aqueous systems often probed by electrodeposition.

Imaging the 3D microstructural changes of ice cream during meltdown.

Ice cream is a multiphase frozen dessert that often melts during distribution and upon consumption. The meltdown phenomenon is one of the concerns in the quality preservation of ice cream for consumer convenience in the frozen food industry. In this context, X-ray tomography was used to visualise and quantify 3D ice crystal and air bubble evolution during the meltdown of ice cream. Two ice cream products, namely I and II, with varying air volume fractions, were evaluated for this study. The results indicated a small mean diameter of 66.43 ± 2.07µm at 0min and decreased to 45.74 ± 3.92µm during 10min of the meltdown of ice cream II. A large mean diameter of ice crystals of 75.02 ± 3.14µm was found in ice cream I, at 0min that decreased significantly (p < 0.05) to 54.30 ± 2.63µm during 10min of the meltdown. The air bubbles were also observed to decrease in mean diameter. The 3D datasets on the ice crystals and air bubbles described in this work provide more insight into the 3D microstructural evolution during the meltdown and are useful in controlling the sensory quality attributes of ice cream desserts.

(Invited) Growth and Characterization of 200 mm SiC Crystals and Substrates

SiC power device technology has over the past years continued to gain massive interest in automotive and industrial applications. The majority of devices is today fabricated on 150 mm diameter substrates while the 200 mm diameter substrates still is at early stage in both development and in terms of mass production. An increase of 50 mm in the wafer diameter corresponds to a 78% larger area and then a corresponding increase of the number of devices per wafer. This change impacts on the productivity of a production line and therefore the cost of the final device can be reduced. Higher production volume and lower cost will lead to a further massive implementation of SiC based power devices in the automotive industry that today is rushing on the path of electrification.At STMicroelectronics we are an early adopter of 200 mm substrates since the first substrate was demonstrated in 2021. Development of 200 mm device quality substrates have progressed well and defect density are today in same range as for 150 mm substrates. The ramp up of production is now made in the new STMicroelectronics plant in Catania while R&D unit in Norrköping Sweden continue to further push the limits of the technology.In this paper, we report the latest progress on STMicroelectronics 200 mm diameter crystals and substrates. We will discuss the most suitable characterization routes available and how we can detect device affecting defects at an early stage. In particular we will start by describing the mechanism that is behind the crystal growth process together with the characterization methods that allow to control the quality of the ingot by monitoring the relevant properties (i.e. bulk defectivity, polytype composition, internal stress). We will then describe the main key parameters to be controlled on the substrate to be sure it is suitable for device making (i.e. mechanical behavior, resistivity, surface roughness, effectiveness of the surface preparation). We will also describe the CVD process that is used to grow on top of the substrate an epitaxial layer with proper resistivity and thickness tailored on the device we need to produce for specific applications. In conclusion we will show some data about the correspondence in between device failure and defectivity on both substrate and epitaxial layer. A comparison of the results collected on both 6” and 8” substrates will be reported to show the excellent job performed in our R&D department in Norrköping to increase the wafer size maintaining the same level of quality. On the other side, our production line in Catania is going to be the first of this kind in Europe with a vertical integration that guarantee process control from the SiC powder to the design and characterization of the final power device.

(Invited) Application of 3D in-Situ X-Ray Visualization to Track the Formation of Dislocation Clusters during PVT Growth of SiC

SiC has become the key player among wide bandgap semiconductors for power electronic applications. Since the first description of the physical vapour transport (PVT) growth process of SiC by Tairov and Tsvetkov (J. Crystal Growth, 43, 209(1978)), there has been steady progress in SiC-based crystal growth, epitaxy and device processing. The success of SiC compared to Si is related to its superior material properties such as extremely high electrical breakdown field and high thermal conductivity compared to the standard silicon counterpart. In addition, SiC device processing utilises much of the standard Si processing equipment. A major reason for the success of SiC in power electronic applications compared to other wide bandgap counterparts such as GaN, Ga2O3 and diamond is related to the availability of large diameter SiC wafer materials (150mm = standard, 200mm = developped). Bulk SiC growth is now a very well developed process with comparatively high yields. The extraordinary physical properties also include obstacles related to the strong chemical bonding and complex phase diagram of the material, which pose challenges to the growth process. Therefore, there are still a number of open questions related to the nucleation, progression and termination of the bulk growth process that require fundamental research in materials science and technology.The aim of this presentation is (i) to give an overview of the state-of-the-art PVT growth process and (ii) to discuss a current research topic dealing with the early stage of the growth process and the defect formation that can occur during the initial nucleation of SiC. We have applied 3D in-situ visualisation of the growth process using X-ray computed tomography to visualise island formation on the large seeding area. These data are related to growth process instabilities such as temperature variations during the seeding process and axial doping level changes from the seed to the newly grown crystal. Both process instabilities induce mechanical stress on the SiC lattice and act as sources for dislocation generation and multiplication. We will show a series of growth processes with varying growth parameters that shed light on the initial growth stage of SiC.As the crystal diameter of SiC increases from 150 mm to 200 mm, the results of this study become increasingly important.

Simulation of crucible-free growth of monocrystalline silicon fibres for mirror suspension in gravitational-wave detectors

Monocrystalline silicon fibres are a promising candidate to support the test mass needed in gravitational-wave detectors. Stringent requirements on material purity and fibre diameter underscore the imperative for crucible-free crystal growth methods, such as Pedestal and Floating Zone techniques. We developed a multiphysics numerical model that simulates the coupling between electromagnetism, heat transfer, fluid flow and phase boundaries for these techniques within the same mathematical framework, which facilitates direct comparisons of both growth techniques. Model validation was addressed using experimental measurements and other simulation tools, and satisfactory agreement was obtained. Our findings indicate that electromagnetic forces are the primary mechanism responsible for stirring the molten silicon at small crystal diameters. The resulting fluid velocity develops slightly transient behaviour, although this has little impact on the phase boundary shapes. The understanding of the growth process enabled by the model will facilitate future optimization of crystal quality and diameter stability.

Effect of sodium alginate ice glazing on the quality of the freeze-thawed fish balls

The effect of 1.0 % (w/v) sodium alginate (SA) glazing on surface frost formation and the quality of frozen fish balls in repeated freeze-thaw (F-T) cycles was studied. The optimal glazing property of 1.0 % SA solution was manifested by high transmittance, excellent water resistance, and high ice glazing rate. After seven F-T cycles, compared with the control, the ice production, thawing loss, and total volatile base nitrogen (TVB-N) value of samples with 1.0 % ice glazing decreased by 28.30 %, 21.02 %, and 27.35 %, while the chewiness and whiteness were increased by 15.02 % and 10.40 %, respectively. Moreover, compared to the control, the microstructure of fish balls glazed with 1.0 % SA was smoother and more uniform, and the ice crystal diameter was smaller. Therefore, 1.0 % SA glazing effectively inhibits the formation of ice crystals, reducing water migration and loss while minimizing damage to the meat structure, thus enhancing the quality of meat products.

A novel bismuth-nickel-aluminium nanocomposite as a protective barrier against nuclear radiation

In the present work, Alovera extract is used as a reducing agent during the versatile solution combustion synthesis of bismuth nickel aluminum nanocomposites (BiNiAl NCs). Standard techniques are used to characterize the obtained BiNiAl NCs. The formation of multi-phase BiNiAl NCs with crystal diameters of 18.20 nm and 22.06 nm was confirmed by Bragg’s reflections. The agglomeration of spherical-shaped nanoparticles was confirmed by the surface morphology of BiNiAl NCs. The presence of Bi, Ni, and Al was analyzed using the EDAX spectrum. The direct energy gap is calculated to be 3.06 eV. Then, using a NaI(Tl) detector coupled with MCA, the shielding characteristics against X-rays and gamma radiation are measured. Shielding standards are a little higher than lead standards. The characteristics of neutron shielding are compared to those of traditional shielding materials. When compared to lead, concrete, and steel, the neutron attenuation characteristics and scattering length of BiNiAl NCs are determined to be effective. The scattering length is found to be 6.6 fm. At 1.511 MeV, the shielding parameters for bremsstrahlung radiation are calculated. While bremsstrahlung dose rate and specific bremsstrahlung constant are found to be greater in comparison with lead, bremsstrahlung efficiency is equivalent to lead. As a result, BiNiAl NCs are very effective in absorbing neutrons, bremsstrahlung radiation, and X/gamma rays.

The influence of ultrasound homogenization on recrystallization during the storage of vegan ice cream

AbstractThis article investigated the influence of ultrasound homogenization and stabilizers (iota carrageenan and its hydrolysates) in the production of vegan ice cream. The cryoscopic temperature, osmotic pressure, overrun, melting time, and microstructure analysis were investigated. Vegan ice cream were stored at −18°C and the recrystallization process was analyzed based on images taken after 24 h, 1 month, and 3 months. According to the results, it was noted that ultrasound homogenization contributed to obtaining smaller ice crystals in ice cream, in comparison to the samples after traditional homogenization. The average diameter of ice crystals in the sample US pretreated, after 3 months of storage was less than 21 μm. The overrun value ranged from 9.22% to 32.36% and the melting time for samples did not exceed 34 min. The analysis of the cryoscopic temperature and osmotic pressure showed that ultrasound contributed to increasing the cryoscopic temperature and lowering the osmotic pressure.Practical ApplicationsThe presented study shows an alternative to dairy products for the vegan ice cream market. Changing mechanical homogenization to ultrasound homogenization in vegan ice cream production might be an effective step for ice cream producers. Owing to the fact that the use of ultrasound during production may reduce the impact of using stabilizers on the recipe of vegan ice cream. Finally, such changes will not result in additional steps in ice cream production which may not generate additional costs.

Succinylation of zein and gelatin hydrolysates improved their ice recrystallization inhibition activity.

The goal of this research was to enhance the ice recrystallization inhibition (IRI) activity of zein and gelatin hydrolysates (ZH and GH, respectively) by succinylation modification. ZH was prepared by Alcalase treatment for 3h and then modified by succinic anhydride (SA); whereas GH was made by Alcalase hydrolysis for 0.25h and succinylated by n-octylsuccinic anhydride (OSA). After 0.5h of annealing at -8°C at 40mg/mL, modified hydrolysates decreased the average Feret's diameter of ice crystal from 50.2μm (polyethylene glycol, negative control) to 28.8μm (SA modified ZH) and 29.5μm (OSA modified GH) in comparison to the unmodified hydrolysates, which had the crystal size of 47.2μm (ZH) and 45.4μm (GH). Also, the two succinylated samples had altered surface hydrophobicity, which potentially contributed to their enhanced IRI activity. Our results indicate that succinylation of food-derived protein hydrolysates can improve their IRI activity.

(Invited) Growth and Characterization of 200 mm SiC Crystals and Substrates

SiC power device technology has over the past years continued to gain massive interest in automotive and industrial applications. Most devices are today fabricated on 150 mm diameter substrates while the 200 mm diameter substrates are still at early stage in both development and in terms of mass production. In this paper, we report the latest progress on STMicroelectronics 200 mm diameter crystals and substrates. To handle the mechanism behind the crystal growth process you need to control the temperature and pressure in the customized graphite growth chamber. We detail the methods that allow to characterize the quality of the ingot by monitoring the relevant properties both related to the grown crystal and to the produced substrate. We also describe the key parameters to be controlled on the substrate to be sure it is suitable for device making (i.e. mechanical behavior, resistivity, surface roughness, effectiveness of the surface preparation).

Evaluation of Radioactivity in Soil Sample from Al-Hadbaa Cement Plant in Nineveh Governorate, Iraq

The fundamental goal of this study is to measure the level of radioactivity in the soil of the area around Al-Hadbaa cement plant, also to evaluate the radiological hazard of radionuclide, gamma-spectroscopy with an HPGe detector with the crystal diameter of 70.6 mm and length of 70 mm has been used to estimate the specific activity of natural radionuclides 226Ra, 232Th, 40K, and artificial radionuclides 137Cs in the fifteen soil samples collected. The results show that the average concentration of specific activity of 226Ra, 232Th, 40K, and 137Cs was 11.17 ± 1.69, 13.38 ± 0.72, 158.36 ± 5.35 Bq/kg, and 1.52 ± 0.19 Bq/kg, respectively. The average specific activity of these radionuclides is discovered to be lower than the global average which is 33 Bq/kg for 226Ra, 30 Bq/kg for 232Th, and 400 Bq/kg for 40K. Radiological hazard indices are determined according to the activity concentration of the radionuclides in the area under study. The outcome of the radiological hazard index is within the globally recognized limit proposed by UNSCEAR which is 1000 μSv/y for annual effective dose and 290 × 10-6 for cancer risk, so it is possible to conclude that there are no radiological hazards as a result of radiation exposure to the workers working in the cement plant as well as the organisms living in the region.

Preparation and properties of anatase - rutile mixed crystal Fe-TiO2 with high catalytic activity under visible light

With the development of society, water pollution is becoming more and more serious, especially dyeing wastewater. Fe-doped TiO2 nano-photocatalyst was prepared by hydrothermal method. The crystal structure, morphology, optical properties, band gap width (Eg) and photocatalytic properties of the synthesized nanoparticles were characterized by XRD, SEM, TEM, EDS, XPS, FT-IR and UV–vis. The results show that Fe-TiO2 is a mixed crystal form of rutile type and anatase type, the average crystal diameter of anatase type is 11 nm, and the diameter of rutile type is 10–50 nm. The addition of Fe can effectively reduce the band gap width of TiO2 from 3.22 eV to 2.33 eV, so as to expand the visible light absorption range. Under 350 W xenon lamp irradiation, the degradation rate of Rhodamine B (RhB) reached 95.3% with 2% Fe-TiO2 nanoparticles in the synergistic effect of sodium persulfate (PS) for 40 min, and the nanoparticles had good reusability. Free radical quenching experiments showed that·OH, SO4-·, e-, and h+ pairs favored RhB degradation. The addition of Fe can form additional energy levels in TiO2, so that the smaller energy photons can excite the electrons and holes trapped in the additional energy levels, so that the absorption of TiO2 is redshifted and the visible light absorption range is extended. Meanwhile, PS accelerates the transformation between Fe(Ⅲ) and Fe(Ⅱ), thereby effectively improving the photocatalytic efficiency.

Cut-Size Diameter Calculation of Salt Crystals From A Hydrocyclone

A hydrocyclone is physical separation equipment employed in solid-liquid processing. An important parameter in hydrocyclone design is the so-called cut-size diameter (D50), which determines the minimum size of the separated solids when the equipment performs at 50% separation efficiency. This paper discusses the calculation of the cut-size diameter (D50) of a hydrocyclone operating in a salt purification pilot plant in Manyar, East Java, Indonesia. The cut-size D50 is calculated based on the residence time approach and compared with the collection efficiency from the mass balance. D50 was found to be 69.73 microns. Moreover, by using Zanker’s nomograph, it was found that at the solid separation efficiency of 80.48%, the minimum diameter of salt crystal (Dmin) is 85 microns. Because the D50 of HC-1 is smaller than Zanker’s design, it can be concluded that the hydrocyclone will work efficiently in separating the expected products.