Microstructure Profiles Research Articles

Alternative technologies for the production of popped sorghum: a comparative study.

Sorghum is the fifth most harvested crop worldwide, being the popped sorghum as one of the most common snacks in India and some Asian regions. Therefore, this study evaluated how the processing method influences the microstructure, volumetric and textural properties of popped sorghum microstructure, volumetric and textural properties. White sorghum "Paloma" variety (11% moisture) was assessed, which was popped using three processing methods: microwave, pan-frying, and hot salt-frying using three temperature levels. Volumetric and yield characteristics were evaluated for the popped kernels, as their microstructure and texture profile. The popped sorghum obtained through the hot salt-frying method had a microstructure composed of polygonal cells. Also, it showed the best volumetric characteristics (volume), good expansion index, and high process yield. Finally, the hot salt-frying method showed better textural features associated with the attributes of a satisfactory product for consumers.

Nutritional and physical characteristics evaluation of giant panda (Ailuropoda melanoleuca) milk in comparison with bovine and caprine milk

The odour, particle size distribution, microstructure and nutrient profile of giant panda milk (GPM) was compared with bovine milk (BM) and caprine milk (CM). SDS-PAGE images of GPM showed clear, deep and uncertain bands different from those for BM and CM. GPM displayed significantly higher levels for free amino acids (p < 0.05), as well as more polyunsaturated and monounsaturated fatty acids. An electronic nose distinguished the three samples; GPM had the strongest response values to sensors. The effective diameter and polydispersity index of GPM were significantly higher than BM and CM (p < 0.05), and the same results were also observed in confocal laser scanning microscopy (CLSM) images. A giant panda milk substitute formulation with the following main nutrients is recommended: protein, 36%; fat, 50%; carbohydrates, 8%. It is also necessary to supplement a small quantity of isoglobotriose, and adjust the milk substitute amino acids and fatty acids ratios.

Micapipe: A pipeline for multimodal neuroimaging and connectome analysis

Multimodal magnetic resonance imaging (MRI) has accelerated human neuroscience by fostering the analysis of brain microstructure, geometry, function, and connectivity across multiple scales and in living brains. The richness and complexity of multimodal neuroimaging, however, demands processing methods to integrate information across modalities and to consolidate findings across different spatial scales. Here, we present micapipe, an open processing pipeline for multimodal MRI datasets. Based on BIDS-conform input data, micapipe can generate i) structural connectomes derived from diffusion tractography, ii) functional connectomes derived from resting-state signal correlations, iii) geodesic distance matrices that quantify cortico-cortical proximity, and iv) microstructural profile covariance matrices that assess inter-regional similarity in cortical myelin proxies. The above matrices can be automatically generated across established 18 cortical parcellations (100–1000 parcels), in addition to subcortical and cerebellar parcellations, allowing researchers to replicate findings easily across different spatial scales. Results are represented on three different surface spaces (native, conte69, fsaverage5), and outputs are BIDS-conform. Processed outputs can be quality controlled at the individual and group level. micapipe was tested on several datasets and is available at https://github.com/MICA-MNI/micapipe, documented at https://micapipe.readthedocs.io/, and containerized as a BIDS App http://bids-apps.neuroimaging.io/apps/. We hope that micapipe will foster robust and integrative studies of human brain microstructure, morphology, function, cand connectivity.

Upper‐Ocean Turbulence Structure and Ocean‐Ice Drag Coefficient Estimates Using an Ascending Microstructure Profiler During the MOSAiC Drift

AbstractSea ice mediates the transfer of momentum, heat, and gas between the atmosphere and the ocean. However, the under‐ice boundary layer is not sufficiently constrained by observations. During the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), we collected profiles in the upper 50–80 m using a new ascending vertical microstructure profiler, resolving the turbulent structure within 1 m to the ice. We analyzed 167 dissipation rate profiles collected between February and mid‐September 2020, from 89°N to 79°30′N through the Amundsen Basin, Nansen Basin, Yermak Plateau, and Fram Strait. Measurements covered a broad range of forcing (0–15 m s−1 wind and 0–0.4 m s−1 drift speeds) and sea ice conditions (pack ice, thin ice, and leads). Dissipation rates varied by over 4 orders of magnitude from 10−9 W kg−1 below 40 m to above 10−5 W kg−1 at 1 m. Following wind events, layers with dissipation W kg−1 extended down to 20 m depth under pack ice. In leads in the central Arctic, turbulence was enhanced 2–10 times relative to thin ice profiles. Under‐ice dissipation profiles allowed us to estimate the boundary layer thickness (4 ± 2 m), and the friction velocity (1–15 mm s−1, 4.7 mm s−1 on average). A representative range of drag coefficient for the MOSAiC sampling site was estimated to (4–6) × 10−3, which is a typical value for Arctic floe observations. The average ratio of drift speed to wind speed was close to the free‐drift ratio of 2% with no clear seasonal or regional variability.

On Characteristics and Mixing Effects of Internal Solitary Waves in the Northern Yellow Sea as Revealed by Satellite and In Situ Observations

This study examines the characteristics, statistics, and mixing effects of internal solitary waves (ISWs) observed in the northern Yellow Sea (YS) during the summers of 2018 and 2019. The mooring stations are located between offshore islands with rough topographic features. Throughout the observation period, the ISWs with vertical displacements of up to 10 m induced prevailing high-frequency (3–10 min period) temperature variations. Synthetic aperture radar (SAR) images showed that the observed ISWs propagate in zonal directions generated around the islands where internal-tide-generating body force is strong. The estimated ISW propagation speed ranges from 0.16 to 0.25 m s−1, which agrees with the Korteweg-de Vries (KdV) model. The ISW intensity exhibits a clear spring-neap cycle corresponding to the local tidal forcing. The constant occurrence of ISWs at low tide suggests an important generation site where the ISWs are tidally generated. The ray-tracing result indicates that this generation site appears to be located at a strait between Dahao and Xiaohao islands. A generalized KdV model successively reproduces the propagation process from the generation site to the mooring station. Following the passage of ISWs, microstructure profiling observations reveal a high turbulent kinetic energy dissipation rate (10−6 W kg−1). The prevalence of ISWs in the study area is believed to play a crucial role in regulating vertical heat and nutrient transport, thereby modulating the biogeochemical cycle.

Blends of palm kernel oil, soybean oil and palm stearin as an alternative to milk fat for frozen dessert application

In this study, the ternary blends of palm kernel oil (PKO), soybean oil (SBO) and two types of palm stearin (PS) (PS33 and PS38) were systematically prepared and evaluated for their application as an alternative to milk fat in frozen dessert. The physicochemical characteristics namely fatty acids constituent, triacylglycerols (TAGs) composition, melting behavior, solid fat content (SFC) and microstructure were studied. All ternary blends of PKO/SBO/PS33 and PKO/SBO/PS38 had comparable microstructure to that of milk fat. However, 80/15/5 (PKO/SBO/PS33) and 80/15/5 to 80/5/15 (PKO/SBO/PS38) mixtures were found to have similar SFC as milk fat at temperature above 20 °C, allowing these ternary blends to be completely melted at body temperature. With this, 80/15/5 (PKO/SBO/PS33) and 80/15/5 to 80/5/15 (PKO/SBO/PS38) mixtures were able to provide similar meltdown and mouth feel as milk fat at room temperature. Nonetheless, fatty acids constituent, TAGs composition and melting behavior of the blends were different from milk fat. This study showed that ternary blends of PKO, SBO and PS at ratios 80/15/5 (PKO/SBO/PS33) and 80/15/5 to 80/5/15 (PKO/SBO/PS38) can be potentially used as a milk fat alternative for frozen dessert application based on its similar microstructure and SFC profile as the milk fat.

Influence of convection and microwave roasting on roasting degree, microstructure and aroma profile of cocoa beans

Influence of convection and microwave roasting on roasting degree, microstructure and aroma profile of cocoa beans

Effect of substrate condition on wire fed electron beam additive deposition

Electron beam wire fed (EB-WF) additive manufacturing (AM) can be utilised for cost-effective part repair in the aerospace industry and, especially for titanium alloys, the vacuum processing effectively mitigates high temperature contamination for enabling reliable high-performance. This research advanced EB-WF additive processing and simulation for depositing Ti–6Al–4V thin walls (3 mm in thickness) that emulates repair of damaged fan and compressor blades. The main focus of this research was to understand the effect of the initial substrate microstructure and residual stress profile on the final deposit properties. The results revealed that the EB-WF additive repair process for depositing Ti–6Al–4V yielded minimal distortion (<350 μm) and residual stresses (<150 MPa (0.15σys)). The initial residual stress states of the substrate were found to have a negligible effect on the final residual stress profiles, from the stress relaxation effect during EB-WF AM. Although significant variance in the microstructure for each substrate condition was present after deposition, their mechanical properties were similar. Deposited test specimens had tensile yield and ultimate strength values ranging between 800-830 MPa and 860–880 MPa, respectively. The similar mechanical properties of the interface were correlated with the microstructural features such as layer bands and titanium alpha (α) colonies.

Satellite‐Based Detection of Secondary Droplet Activation in Convective Clouds

AbstractWe present a new approach of analyzing and interpreting vertical profiles of cloud microstructure obtained by satellite remote sensing. The method is based on a spectral bin microphysics adiabatic parcel model and aims to elucidate the effects of aerosols on the evolution of convective clouds and related microphysical processes, including the activation of cloud condensation nuclei (CCN), the growth of cloud droplets, and the formation of precipitation. Characteristic features in the vertical profiles of effective radius (re) and temperature (T) reveal different microphysical zones in convective clouds related to the change increase of re with decreasing T. The classification of the different microphysical zones includes the (a) condensational growth of droplets, (b) growth by coalescence, (c) rainout, (d) secondary droplet activation zone (SAZ), (e) mixed‐phase of ice particles and water droplets, and (f) glaciation of the cloud. The detection of the SAZ is introduced here for the first time. This method allows us to identify the activation of aerosol particles above cloud base and their role in the invigoration of deep convective clouds.

Microstructure profiling, lattice dynamics, and morphological studies on multi-excitonic vanadium bismuth oxide compound systems

Microstructure profiling, lattice dynamics, and morphological studies on multi-excitonic vanadium bismuth oxide compound systems

Quasi-Static Compression Response of Carbon Fiber Reinforced 2.5D Woven Composites at Different Loading Directions.

2.5D woven composites have been increasingly used in aerospace and military applications due to their excellent mechanical properties. In this research, 2.5D woven composites were produced, and their compression responses were investigated in different directions by compression experiments. XR-CT (X-ray computed tomography) technology was used to observe the microstructural damage profiles, and to analyze the failure mechanism of the material. The results show that when subjected to compression loads, the maximum load-bearing capacity of the material in the thickness direction was better than the maximum load-bearing capacity in the warp and weft directions. The compressive strength of the material in the warp and weft directions was lower than that in the thickness direction, and compression damage patterns in each direction also differed.

Threadfin bream surimi gel containing squid fin protein hydrolysate: Textural properties, acceptability, and volatile profile.

Gel properties of threadfin bream surimi gels with squid fin protein hydrolysate (SFPH) at various concentrations (0, 1, 2, 3, and 4%; w/w) were determined. The gel without SFPH (CON) had the highest breaking force (BrF) and deformation (DeF) as compared to those with SFPH (p<0.05). Among the gel with SFPH, gel containing 1 and 2% SFPH (SFPH-1 and SFPH-2, respectively) had the highest BrF, whereas the lowest value was obtained when 4% SFPH was used (SFPH-4) (p<0.05). The whiteness of all samples was slightly decreased with an upsurging amount of SFPH. However, water holding capacity was increased with augmenting levels of SFPH (p<0.05). Sensory analysis revealed that SFPH-2 had a higher squid odor and flavor likeness score than CON (p<0.05). Textural properties, especially hardness, were decreased with increasing SFPH, except for SFPH-1 and SFPH-2 (p>0.05). In addition, the rheological properties, microstructure, and volatile profile of the selected surimi gel were also studied. The storage modulus (G') of SFPH added samples was decreased as compared to the CON sample. The CON gel had a finer and more compact network as compared to SFPH-2 and SFPH-4 samples. Volatile profiles indicated that alcohols, carboxylic acids, ketones, and ether were the major volatile compounds present in both gel samples. Furthermore, thiophene, 3-methyl-, contributing to squid flavor, was found in the SFPH-2 sample. Overall, SFPH at 2% could act as a flavorant in the threadfin bream surimi gel without markedly negative impact on gelling and textural properties, while providing squid odor and flavor to the resulting gel. PRACTICAL APPLICATION: The various low-valued byproducts generated from the squid processing industry could result in various environmental problems. Those byproducts are rich in various biomolecules such as proteins, fats, enzymes, and so forth, which could be utilized to produce value-added products. Among them, protein hydrolysate (PH) rich in amino acids with excellent antioxidant properties could serve as an alternative flavorant. Therefore, PH from squid byproducts, especially fins, could be applied in foods such as fish balls, surimi gels, and so forth to enhance the nutritional and flavoring profile of a finished product. Moreover, bioactive peptides in PH with antioxidant potential could retard the oxidation of proteins and lipids.

Polarization effects on ablation efficiency and microstructure symmetricity in femtosecond laser processing of materials-developing a pattern generation model for laser scanning.

This paper investigated the effects of femtosecond laser beam polarization on ablation efficiency and microstructure symmetricity for 64FeNi alloy (Invar) sheet processing to fabricate fine metal masks. It was found that the ablation efficiency for linear polarization was approximately 15% higher than that for circular polarization due to electric field enhancement induced by low-spatial-frequency laser-induced periodic surface structures (LIPSS). The hole size and sidewall taper angles for the microstructures generated by linear polarization were asymmetric, whereas those generated by circular polarization were symmetric due to non-oriented LIPSS. The asymmetric and symmetric three-dimensional microstructure profiles, measured by using a confocal laser scanning microscope, were verified by employing an analytical model that was derived using the total input fluence and the ablation rates for linear and circular polarizations, respectively.

Microstructure and properties of B + C + N ternary hardening layers on Q235 low-carbon steel prepared by plasma electrolysis

Ternary surface hardening layers were prepared on the Q235 low-carbon steel by plasma electrolytic borocarbonitriding(PEB/C/N) under constant voltage of 260–300 V for 30 min. The microstructure, phase components and hardness depth profiles of the B + C + N ternary hardening layers were examined. The ternary hardening layers were composed of a boride layer with single Fe2B phase and a transition layer. The thickness of modified boride layers on the PEB/C/N samples was about 10 μm, 15 μm and 22 μm at 260 V, 280 V and 300 V, respectively. The maximum hardness of boride layer was 2400 HV for the 300 V PEB/C/N sample. The surface free energy of bare Q235 steel and PEB/C/N samples at 260, 280 and 300 V were 41.084, 32.039, 26.906 and 25.726 mJ/m2, which were calculated on the basis of their contact angles for water and n-hexadecane. Furthermore, the hardening layers exhibited excellent corrosion behavior due to the improved hydrophobicity for the dense boride layer. The lowest wear rate of PEB/C/N sample at 300 V is about 2.0375 × 10−6 mm3/ N·m, which is only 1/15 of the bare Q235 steel, the ternary hardening treatment shows a better wear resistance than the bare Q235 steel.

Understanding the role of in-flight particle temperature and velocity on the residual stress depth profile and other mechanical properties of atmospheric plasma sprayed Al2O3 coating

This report deals with the influence of particle temperature and velocity on the microstructure, mechanical properties and residual stress depth profile of plasma sprayed alumina coating. The coatings were produced by varying the particle temperature while maintaining a relatively fixed particle velocity, and vice versa. Residual stress profiles were acquired by measuring the stress in successive layers using X-ray Sin2ψ technique. A substantial increase in hardness and indentation modulus by 76% and 64%, respectively were observed with an increase in particle temperature. With an increase in velocity, coating porosity was found to decrease initially. However, at a high velocity, porosity again increased to a limited extent. The mechanical properties were found to depend strongly on porosity. An increase in particle temperature resulted in an increase in the tensile residual stress in the coatings. Moreover, partial recovery of the grit blasted compressive substrate occurred during spraying owing to an annealing effect.

Technical note: Turbulence measurements from a light autonomous underwater vehicle

Abstract. A self-contained turbulence instrument from Rockland Scientific was installed on a light autonomous underwater vehicle (AUV) from OceanScan Marine Systems and Technology Lda. We report on the data quality and discuss limitations of dissipation estimated from two shear probes during a deployment in the Barents Sea in February 2021. The AUV mission lasted for 5 h, operating at a typical horizontal speed of 1.1 m s−1. The AUV was programmed to find and cross the maximum along-path thermal gradient at 10, 20 and 30 m depths along 4 km transects. Although the AUV vibrations contaminate the shear probe records, the noise is mitigated by removing vibration-induced components from shear spectra using the accelerometer signal measured in multiple directions. Dissipation rate estimates in the observed transects varied in the range 1×10-8 and 6×10-6 W kg−1, with the values from the two orthogonal probes typically in agreement to within a factor of 2. Dissipation estimates from the AUV show good agreement with nearby vertical microstructure profiles obtained from the ship during the transects, indicating that the turbulence measurements from the AUV are reliable for this relatively turbulent environment. However, the lowest reliable dissipation rates are limited to 5×10-8 W kg−1, making this setup unfit for use in quiescent environments.

Effects of powder compression and laser re-melting on the microstructure and mechanical properties of additively manufactured parts in laser-powder bed fusion

Achieving good surface profile and low levels of porosity are prime challenges in the Laser-Powder Bed Fusion (L-PBF) additive manufacturing technique. In order to optimise these properties, post-processing is often required. However, the compression of powder spread on the build plate and re-melting of each build layer during the L-PBF process could address these challenges. In this study, the effect of different powder compression ratios and laser re-melting regimes on the density, microstructure morphology, surface profile and mechanical properties of L-PBF produced parts were investigated. Two different metal printers with same laser processing parameters were used to fabricate 10 × 10 × 10 mm3 stainless steel 316L samples. To examine the impact of compression ratio and layer re-melting, one set of samples was prepared with three different compression levels for each layer and a second set of samples either a single or double set of laser passes for each layer. The Volumetric Energy Density (VED) range examines was from 26.7 J/mm3 to 80 J/mm3. Density, hardness, elastic modulus, microstructure and surface profiles of the printed samples were characterised. A 3% increment in density and a 50% reduction in the surface roughness were achieved using a laser double pass over each layer. The results demonstrate, by applying different powder compression ratios onto the powder bed and by re-melting each layer, that the density, surface roughness and the elastic modulus of the produced samples can be improved.

Part I: Hydrological properties within the eastern Indonesian throughflow region during the INDOMIX experiment

The Indonesian Mixing (INDOMIX) cruise of July 2010, resolves the Pacific Ocean water masses spreading from the Halmahera Sea through the Seram Sea, Manipa Strait, Banda Sea, to the Ombai Strait, and along the southern margin of Lesser Sunda Arc across the northern Savu Sea, Sumba Strait, and south of Lombok Strait. This paper focuses on the characteristics and stratification of the water masses, along this path and Part II of this study discusses the biogeochemical aspects. Two companion papers on quantification of turbulent mixing have been published elsewhere. We find: a) A marked transformation of South Pacific (SP) thermocline water within a sharp salinity front between the Halmahera Seram Seas. Tidally induced vertical mixing is the main process weakening the SP stratification, as suggested by a simple 1-dimensional diffusion model forced by vertical diffusivity of INDOMIX vertical microstructure profiler dataset. The transformation of SP water by vertical mixing can occur after 3 days, which is in good agreement with previously reported water mass residence times. Lateral advection plays a minor role; b) Interleaving salinity structure within the thermocline of the central Halmahera Sea and two deeper inflow channels. The interleaving salinity features within the central Halmahera Sea thermocline occurs where vertical diffusivity is relatively weak, compared to the vertical mixing at entry/exit portal that removes the interleaving salinity features. Two deeper inflow channels (about 950 m and 740 m depth) in the entry portal of the Halmahera Sea are mapped from the multi-beam echo sounder measurement, where both channels allow the renewal of SP thermocline water and salinity interleaving processes; c) Northward flow of thermocline water (100–200 m depth) in the Manipa Strait that injects Banda homogeneous salinity water into Seram Sea that erode Halmahera salty water via strong diapycnal mixing; d) Cyclonic upper layer circulation in Banda where eastward (westward) flow occurs in the northern (southern) Banda, confirmed by recent modeling study; and e) Relative salty Indian Ocean intermediate water flowing along southern margin of the Lesser Sunda Arc, within the South Java Undercurrent. Two distinct upper thermocline water, due to different source of Indonesian Throughflow (ITF) water, are found in the Banda Sea: fresher and colder water contrasting to saltier and warmer water that converge in this confluence region. Beneath it, Banda intermediate homogeneous salinity water and low dissolved oxygen water is dominant.

Direct Measurements of Turbulence in the Upper Western Pacific North Equatorial Current over a 25-h Period.

Measurements of the turbulent kinetic energy dissipation rate (ε) were conducted by a free-fall microstructure profiler in the western Pacific North Equatorial Current (WPNEC) during a continuous period of 25 h, from the sea surface to about 160 m depth. In the mixed layer (ML), ε values were typically on the order of 10−8∼10−7 W kg−1, and an obvious diurnal cycle existed in the upper 40 m of the surface mixing layer. Below the ML, ε was reduced to 10−9∼10−8 W kg−1 with some patches of high ε reaching 10−7.5 W kg−1. The barrier layer was identified in the nighttime with a maximum thickness of 20 m, and it was eroded by the advection of freshwater within the lower part of the isothermal layers associated with an anticyclonic eddy in the afternoon. A simple scaling relevant to shear (S2) instability and stratification (N2) that can predict turbulent dissipation rates in the transition layer, between the well-mixed layer and the thermocline below, was obtained through the scaling . Besides turbulence, double-diffusive processes also contributed to the vertical mixing levels in the upper WPNEC.

Flow of transversely isotropic fluid in curved pipes

We study a fully developed creeping flow of nematic liquid crystals in a curved pipe with a circular cross-section. A special limit of zero Deborah number and an infinite Ericksen number limit is considered, so the flow and orientation of the director are described by the transversely isotropic fluid (TIF) model. Analytical solutions are obtained by expanding the governing equation in the limit of small pipe curvature δ, defined as the ratio of the pipe radius to the radius of the bend. We show that the presence of bend curvature alters the orientation of the microstructure and axial velocity profile. The additional non-Newtonian stress generates a secondary flow, which consists of two counter-rotating vortices. Two mechanisms responsible for the secondary motion are identified (1) combination of normal stresses with pipe curvature (2) asymmetry of the stress distribution. The relative strength and direction of those mechanisms in the framework of the transversely isotropic fluid model is quantified through a parameter q. For all liquid crystals considered in this paper, the stress asymmetry dominates, thus controlling the direction of the secondary flow, which is opposite to the secondary flow induced by inertia. Finally, we quantify the contribution of the secondary motion to the viscous dissipation and show that additional shearing increases viscous losses and power consumption without contributing to the throughput.