Precipitation Bands Research Articles

North Atlantic Oscillation Effect on Interannual Variability in Winter Precipitation over the Gulf Stream

AbstractIn winter, the warm water of the Gulf Stream anchors a salient precipitation band. Previous studies suggested a close relationship between the sea surface temperature (SST) front and the precipitation band through sea level pressure (SLP) adjustment. This study uses 17 years of high-resolution precipitation observations to reveal that the variation in wintertime precipitation over the Gulf Stream is related to the North Atlantic Oscillation (NAO) at the interannual time scale. The moisture budget analysis shows that the climatological precipitation band is supported by the large evaporation from the Florida Current, mean flow, and synoptic moisture convergence within the boundary layer, with a negative contribution from mean-flow moisture advection by the prevailing northwesterlies. For interannual variability, by contrast, the negative contribution of mean-flow moisture advection significantly decreases due to anomalous southeasterlies west of the intensified Azores high at the positive NAO phase. The contributions from mean-flow moisture advection and mean and synoptic convergence vary greatly along the Gulf Stream. In addition, mean-flow and synoptic moisture convergences positively contribute to the precipitation band both in climatology and at the interannual time scale, indicative of a positive feedback between precipitation and boundary layer convergence. Our analysis suggests that the SLP adjustment mechanism across the SST front is still at work in interannual variability, and the variation of synoptic activities over the Gulf Stream plays an important role in modulating the frontal precipitation. By relating the frontal precipitation to the NAO, this study bridges small-scale air–sea interaction and large-scale atmospheric circulation.

Highly Resolved Mn Kβ Emission: A Potential Probe in Laboratory for Analysis of Ligand Coordination around Mn Atoms in Gels and Solutions.

Mn Kβ spectra of Mn, MnO, MnSO4·H2O, KMnO4, 0.50 M MnSO4 aqueous solution, and the precipitation bands of Mn-Fe-based Prussian blue analogs formed in 2.4 wt.% agarose gel ("Gel") were measured using a laboratory-use X-ray setup with ∼2.6 eV instrumental resolution, which comprises a cylindrically bent Si (400) crystal monochromator and a spherically bent Ge (440) crystal analyzer. The oxidation-state dependent shift of the Mn Kβ1,3 peak (∼1 eV) was clearly observed for Mn, MnO, and KMnO4, confirming that the employed setup can acquire the key features of Mn Kβ spectra. The Mn Kβ spectra of MnSO4·H2O, the 0.50 M solution, and Gel exhibited small but distinguishable differences, whereas the spectra acquired at two positions in Gel were almost the same. These results suggest that highly resolved Mn Kβ spectra can be helpful for assessing ligand coordination around Mn atoms in gels and solutions.

Sensitivity of Summer Precipitation over Korea to Convective Parameterizations in the RegCM4: An Updated Assessment

This study investigates the performance of the latest version of RegCM4 in simulating summer precipitation over South Korea, comparing nine sensitivity experiments with different combinations of convective parameterization schemes (CPSs) between land and ocean. In addition to the gross pattern of seasonal and monthly mean precipitation, the northward propagation of the intense precipitation band and statistics from extreme daily precipitation are thoroughly evaluated against gridded and in situ station observations. The comparative analysis of 10-year simulations demonstrates that no CPS shows superiority in both quantitative and qualitative aspects. Furthermore, a nontrivial discrepancy among the different observation datasets makes a robust assessment of model performance difficult. Regardless of the CPS over the ocean, the simulations with the Kain–Fritsch scheme over land show a severe dry bias, whereas the simulations with the Tiedtke scheme over land suffer from a limited accuracy in reproducing spatial distributions due to the excessive orographic precipitation. In general, the simulations with the Emanuel scheme over land are better at capturing the major characteristics of summer precipitation over South Korea, despite not all statistical metrics showing the best performance. When applying the Emanuel scheme to both land and the ocean, precipitation tends to be slightly overestimated. This deficiency can be alleviated by using either the Tiedtke or Kain–Fritsch schemes over the ocean instead. As few studies have applied and evaluated the Tiedtke and Kain–Fritsch schemes to the Korean region within the RegCM framework, and this study introduces the potential of these new CPSs compared with the more frequently selected Emanuel scheme, which is particularly beneficial to RegCM users.

Shaping Microcrystals of Metal–Organic Frameworks by Reaction–Diffusion

AbstractWhen components of a metal–organic framework (MOF) and a crystal growth modulator diffuse through a gel medium, they can form arrays of regularly‐spaced precipitation bands containing MOF crystals of different morphologies. With time, slow variations in the local concentrations of the growth modulator cause the crystals to change their shapes, ultimately resulting in unusual concave microcrystallites not available via solution‐based methods. The reaction–diffusion and periodic precipitation phenomena 1) extend to various types of MOFs and also MOPs (metal–organic polyhedra), and 2) can be multiplexed to realize within one gel multiple growth conditions, in effect leading to various crystalline phases or polycrystalline formations.

Shaping Microcrystals of Metal-Organic Frameworks by Reaction-Diffusion.

When components of a metal-organic framework (MOF) and a crystal growth modulator diffuse through a gel medium, they can form arrays of regularly-spaced precipitation bands containing MOF crystals of different morphologies. With time, slow variations in the local concentrations of the growth modulator cause the crystals to change their shapes, ultimately resulting in unusual concave microcrystallites not available via solution-based methods. The reaction-diffusion and periodic precipitation phenomena 1) extend to various types of MOFs and also MOPs (metal-organic polyhedra), and 2) can be multiplexed to realize within one gel multiple growth conditions, in effect leading to various crystalline phases or polycrystalline formations.

Ultrafine lamellar structure AM60B magnesium alloy sheet prepared by high strain rate rolling

The rolled sheet was successfully prepared for the as-cast AM60B magnesium alloy by using the high strain rate rolling (HSRR) in the temperature range of 310 °C – 370 °C. An ultrafine lamellar structure consisting of small angle grain boundaries was developed in the HSRRed sheet by the detwinning of high-density twins. The ultrafine lamellar structure was characterized by means of the high-resolution transmission electron microscopy technique, and the effect of temperature on the detwinning was analyzed. Furthermore, the morphological difference of the ultrafine lamellar structure and its effect on the mechanical properties of the rolled sheet were investigated. The results show that the dislocation motion, cross twinning, dynamic recovery and dynamic recrystallization have multiple interactions with the detwinning behavior in different modes. And the degree of detwinning and the post-rolling microstructure are greatly affected by the interaction. Dynamic precipitation of the second phase is induced by the HSRR process at 370 °C. Nano particles precipitate along twin grain boundaries and form the ‘precipitation band’. However, the detwinning is not affected by the ‘precipitation band’. In addition, it is also revealed from the results that a uniform and fine fully-lamellar structure is developed as the HSRR process is conducted at a medium temperature of 340 °C. Meanwhile, the alloy rolled at 340 °C has relatively optimal mechanical properties, and the strength and ductility are well balanced.

Microstructure and hot deformation behavior of a new aluminum–lithium–copper based AA2070 alloy

The effects of initial microstructure on hot compression behavior of a new Al–Li–Cu alloy AA2070 were studied in the temperature range of 250 °C–450 °C and strain rate range of 0.001 s−1 - 0.1 s−1. Scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to characterize microstructure prior to and post deformation. Two types of major strengthening precipitates were identified: Al2CuLi (T1) phase with habit planes parallel to {111}Al and Al2Cu/Al3Li (Ɵ'/δ′) composite precipitates with habit planes parallel to {100}Al, in the initial microstructure. The combination of these precipitates provides strong resistance to dislocation slip. While dynamic recovery is the main softening mechanism at compression temperatures below 450 °C, dynamic recrystallization dominates softening at 450 °C. T1 precipitate bands consisting of multiple fine T1 precipitates exist in microstructure after hot deformation at 250 °C and 350 °C. The formation mechanisms of T1 precipitate bands and fine T1 precipitates are discussed in light of shearing deformation of T1 precipitates. After hot deformation at 350 °C, Ɵ'/δ′ composite structure is lost and only Ɵ′ precipitates exist in the post-deformation microstructure. The interface between Ɵ′ precipitate and aluminum matrix becomes incoherent. The optimal processing conditions of this alloy have been identified as a temperature of 450 °C and a strain rate of 0.001 s−1, with significant grain refinement and the weakest deformation texture, which are consistent with the analysis results of hot work efficiency and instability using pseudo processing maps.

Nonclassic Evolution of a Cold-Frontal System across the Western United States during the Intermountain Precipitation Experiment (IPEX)

Abstract A cold-frontal passage through northern Utah was studied using observations collected during intensive observing period 4 of the Intermountain Precipitation Experiment (IPEX) on 14–15 February 2000. To illustrate some of its nonclassic characteristics, its origins are considered. The front developed following the landfall of two surface features on the Pacific coast (hereafter, the cold-frontal system). The first feature was a surface pressure trough and wind shift associated with a band of precipitation and rope cloud with little, if any, surface baroclinicity. The second, which made landfall 4 h later, was a wind shift associated with weaker precipitation that possessed a weak temperature drop at landfall (1°C in 9 h), but developed a stronger temperature drop as it moved inland over central California (4°–6°C in 9 h). As the first feature moved into the Great Basin, surface temperatures ahead of the trough increased due to downslope flow and daytime heating, whereas temperatures behind the trough decreased as precipitation cooled the near-surface air. Coupled with confluence in the lee of the Sierra Nevada, this trough developed into the principal baroclinic zone of the cold-frontal system (8°C in less than an hour), whereas the temperature drop with the second feature weakened further. The motion of the surface pressure trough was faster than the posttrough surface winds and was tied to the motion of the short-wave trough aloft. This case, along with previously published cases in the Intermountain West, challenges the traditional conceptual model of cold-frontal terminology, structure, and evolution.

Effect of Cu and Mg on the corrosion behavior of 4004/Al-Mn-Cu-Mg-Si/4004 aluminum alloy brazing sheet

Higher strength and better corrosion resistance are necessary to enable the thickness reduction of the aluminum alloy brazing sheets. In this work, an age-hardenable Al-Mn-Cu-Mg-Si core alloy was developed by the addition of Mg, Si and Cu. The corrosion behavior of 4004/Al-Mn-Cu-Mg-Si/4004 aluminum alloy brazing sheet in sea water acidified accelerated test (SWAAT) was investigated and compared with the traditional 4004/3003/4004 aluminum alloy brazing sheet. The microstructure was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). After brazing, it was found that the microstructures of two aluminum alloy brazing sheets from outer to the center were precipitate-free zone (PFZ), the band of dense precipitates (BDP) and core material, respectively. In particular, both Cu and Mg concentration gradients were formed in the BDP region of 4004/Al-Mn-Cu-Mg-Si/4004. Moreover, the SWAAT results showed exfoliation corrosion in 4004/Al-Mn-Cu-Mg-Si/4004, while in 4004/3003/4004, severe inter-granular corrosion in core material was observed after corrosion for 584 h. The theoretical electric potential distribution showed that the presence of Cu and Mg concentration gradient promoted the formation of the electric potential trough in the BDP region, which may be the reason for the occurrence of exfoliation corrosion in 4004/Al-Mn-Cu-Mg-Si/4004.

Dislocation arrays, precipitate bands and free zones in forged Mg-Gd-Y-Zr alloy

Dislocation arrays are extensively generated in the hammer forged and then annealed Mg-8.3 Gd-2.6 Y-0.4 Zr (wt. %) alloy. Microscopy characterizations reveal a high thermal stability of these dislocation arrays. During ageing treatment, dislocation arrays act as preferred sites for precipitation of β' phase, promoting the formation of the bamboo-like precipitate bands, and resulting in a depletion of solutes nearby and the formation of precipitate free zones (PFZs) along these bands. The forged samples after annealing and then ageing at an optimized temperature of 265 °C for different periods exhibit a similar strength and strain hardening but an increased elongation with ageing time, suggesting that the precipitate bands act as strong barriers for the motion of dislocations and twins while PFZs can effectively enhance deformability of Mg-Gd-Y-Zr alloy.

The non-linear relationship between the western North Pacific anticyclonic circulation and Korean summer precipitation on subseasonal timescales

It has been widely known that the pulse of the western North Pacific anticyclonic circulation (WNPAC) plays a key role on East Asian summer climate variability in subseasonal to interannual time scales. Yet, the relation between the WNPAC and summer precipitation over Korea is not robust on seasonal and subseasonal timescales for the recent few decades. Here, we show that the low correlation between WNPAC and Korean precipitation is attributable to their distinctive non-linear relationship and investigate detailed features in their four different phase relationships on subseasonal time scales. First, the positive Korean precipitation anomaly occurs as the part of zonally elongated precipitation band along with the positive WNPAC anomaly closely connected with the decaying phase of El Nino and Indian Ocean warming. The second case is enhanced Korean precipitation accompanying with negative WNPAC anomaly. In this case, the negative WNPAC anomaly constitutes a part of atmospheric wave train across the North Pacific and this feature is associated with the decaying phase of La Nina. The typhoon-related precipitation event also contributes to this case. Third, the negative Korean precipitation anomaly arises when the low-level easterly anomaly along with the northern flank of negative WNPAC anomaly leads to suppressed convective activity in Korea. Lastly, the negative Korean precipitation anomaly happens with the positive WNPAC anomaly when anomalous high covers entire East Asia and the WNP mainly during the decaying phase of central Pacific El Nino. The understanding of the non-linear relationship between WNPAC and Korean precipitation in this study provides better insight into the potential impacts of El Nino-Southern Oscillation and circulation/convection anomaly over the WNP on summer Korean precipitation.

Validation of Snow Multibands in the Comma Head of an Extratropical Cyclone Using a 40-Member Ensemble

Abstract This paper investigates the ability of the Weather Research and Forecasting (WRF) Model in simulating multiple small-scale precipitation bands (multibands) within the extratropical cyclone comma head using four winter storm cases from 2014 to 2017. Using the model output, some physical processes are explored to investigate band prediction. A 40-member WRF ensemble was constructed down to 2-km grid spacing over the Northeast United States using different physics, stochastic physics perturbations, different initial/boundary conditions from the first five perturbed members of the Global Forecast System (GFS) Ensemble Reforecast (GEFSR), and a stochastic kinetic energy backscatter scheme (SKEBS). It was found that 2-km grid spacing is adequate to resolve most snowbands. A feature-based verification is applied to hourly WRF reflectivity fields from each ensemble member and the WSR-88D radar reflectivity at 2-km height above sea level. The Method for Object-Based Diagnostic Evaluation (MODE) tool is used for identifying multibands, which are defined as two or more bands that are 5–20 km in width and that also exhibit a >2:1 aspect ratio. The WRF underpredicts the number of multibands and has a slight eastward position bias. There is no significant difference in frontogenetical forcing, vertical stability, moisture, and vertical shear between the banded versus nonbanded members. Underpredicted band members tend to have slightly stronger frontogenesis than observed, which may be consolidating the bands, but overall there is no clear linkage in ambient condition errors and band errors, thus leaving the source for the band underprediction motivation for future work.

EFFECT OF ALLOYING ELEMENTS ON CORROSION POTENTIAL AND CORROSION PROPAGATION PROCESS OF MULTILAYER ALUMINUM-BRAZED SHEET

The cross-sectional depth microstructure profiles for a multilayer AA4045/AA3003*/AA4045 brazed sheet were observed and determined by focused ion beam-transmission electron microscopy (FIB-TEM) and energy dispersive spectrometer (EDS). The corrosion propagation of the multilayer brazed sheet in the sea water acidified accelerated test (SWAAT) was investigated by electrochemical impedance spectroscopy (EIS). The measured corrosion potentials of different layers of the multilayer aluminum sheet have been carried out according to ASTM G69-97 standard test method. To reveal the effect of the alloying elements on corrosion behavior, the theoretical corrosion potential of the band of dense precipitates (BDP) zone and core materials was also calculated according to the theoretical corrosion potential model. The electrochemical results showed that there were potential differences between the precipitates free zone (PFZ) and BDP zone as well as BDP zone and the core materials. The EIS test and equivalent circuits (EC) suggested that the capacitive time constant at low frequencies correspond to the corrosion of the BDP zone in the form of exfoliation corrosion. The corrosion propagation process could be identified into four stages: the dissolution of the eutectic [Formula: see text]-Al in the re-solidified cladding in the form of pitting corrosion; the corrosion of the primary [Formula: see text]-Al grain boundaries in the form of inter-granular corrosion (IGC); the corrosion of the BDP zone in the form of exfoliation corrosion; and the corrosion of the core material in the form of IGC.

Coupled Ocean–Atmosphere Summer Intraseasonal Oscillation over the Bay of Bengal

This study shows the active role of subsurface ocean temperature in the evolution of coupled intra-seasonal oscillation (ISO) in the Bay of Bengal (BoB) using multi-satellite observations and ocean analysis product. Satellite-derived humidity profiles obtained from the atmospheric infrared sounder (AIRS) show that intense rains over the BoB are associated with the moistening (drying) in the lower and mid-troposphere during the active (break) phase of summer intraseasonal oscillation (ISO). Anomalous moistening in the mid-troposphere up to 500 hPa ahead of the maximum precipitation band over north BoB gives a precursor signal for the northward movement of the rain band. During the active (break) phase, the upper-tropospheric positive (negative) temperature anomaly ahead of the maximum rain band also sets a precondition by heating the mid- to upper troposphere. Daily subsurface temperature from Global Ocean Data Assimilation System (GODAS) analysis show that during the active phase, tropospheric moistening (drying) coincides with the subsurface warm (cold) temperature up to 200-m depth. The upper ocean warms uniformly by ~ 1 °C during the active phase as compared to the break phase in the entire BoB. The presence of a thin warm layer below the maximum rain band creates an environment conducive to sustaining the active phase on the ISO time scale. A positive sea surface temperature (SST) anomaly along with upper ocean warming ahead of a rain band in the north BoB in association with lower and mid-tropospheric moistening sets a precondition for the northward movement of the rain band. The anomalous warming (cooling) in the thermocline is associated with deeper (shallower) thermocline depth [23° isotherms (D23)] and coincides with the mixed-layer warming.

Key Role of the Kuroshio Current in the Formation of Frontal Structure of an Extratropical Cyclone Associated with Heavy Precipitation

AbstractIn this study, the authors examined how the Kuroshio Current affected the frontal structure of an extratropical cyclone associated with heavy precipitation. We focused on an extratropical cyclone and related heavy precipitation on Miyake Island, which is situated near the Kuroshio Current, in January 2017. We first investigated the frontal structure and the attendant precipitation using observational data and objective analysis data. As the cyclone grew around the Kuroshio Current, a nonclassic front (outer front) intensified to the north of a warm front. A line‐shaped precipitation band developed along the outer front, contributing to the heavy precipitation on Miyake Island. The outer front lay along a sea surface temperature (SST) front associated with the Kuroshio Current in its early life stage. To clarify the impact of the SST front on the formation of the incipient outer front, we next conducted cloud‐resolving numerical experiments using SST distributions with and without the oceanic frontal structure. In the real SST experiment, sensible heat supply from the Kuroshio Current was large, while the amount from the ocean on the northern side of the warm current was small. This meridional difference in sensible heating caused frontogenesis along the SST front, which created the incipient front. Consequently, the real SST experiment reproduced the formation of the front. In contrast, the SST sensitivity experiments did not simulate such a sensible heating pattern or front formation. Thus, the Kuroshio Current played a key role in forming the incipient outer front and contributed to the heavy precipitation.

Heavy Ice Precipitation Band in an Oceanic Extratropical Cyclone Observed by GPM/DPR: 1. A Case Study

AbstractHeavy ice precipitation (HIP) flags in the products of dual‐frequency precipitation radar (DPR) on board the Global Precipitation Measurement (GPM) core satellite indicate the existence of large ice particles. In this study, we analyzed the distribution of a HIP band detected along the warm front of an oceanic extratropical cyclone. The HIP band was more than 125 km long and probably exceeded the 245‐km range of the Ku‐band precipitation radar. We found two zones with distinct microphysical processes in the HIP band. Ice particles near the echo top height showed little change in their median size with height, where frontogenetical updraft was maximum. This suggests that particles are generated and grown in this zone by the updrafts. In the zone below, the particle sizes increased as the height decreased, implying particles aggregate as they fall.

Tropical–Mid-Latitude Interactions: Case Study of an Inland-Penetrating Atmospheric River During a Major Winter Storm Over North America

ABSTRACTA detailed analysis is performed on an inland-penetrating atmospheric river (AR) driven by and coupled to a Colorado cyclone in the first week of February 2016. This winter weather system was initiated by a trough of low pressure moving across the Rocky Mountains from the California coast. The low-level jet ahead of the trough was capable of extracting water vapour from the Gulf of Mexico to feed a cyclone on the lee side of the Rocky Mountaains, and the jet stream eventually transformed into a powerful AR. The warm, moist flow from the south produced a narrow band of heavy precipitation along the major axis of the AR across the central and eastern United States and generated significant freezing rain in parts of the northeastern United States and eastern Canada as the AR flowed over the warm front. It is suggested that, in an operational weather forecasting and warning environment, ARs can be easily identified by using the vertically integrated horizontal water vapour transport, and the major AR contribution to heavy precipitation can be estimated from the horizontal moisture convergence. It is demonstrated that the AR analysis in this case can assist operational meteorologists in understanding and conceptualizing winter storm development and the associated high-impact weather pattern. The operational predictability of this winter storm and its possible teleconnection with the Madden–Julian Oscillation (MJO) are also investigated. Our lagged composite analysis reveals that a statistically significant increase in water vapour transport from the Gulf of Mexico over the North American continent could occur about 10–20 days after the MJO-related convection anomaly reaches the tropical Indian Ocean.

The influence of metallurgical state of substrate on the efficiency of plasma electrolytic oxidation (PEO) process on magnesium alloy

A Gd,Y rare-earth containing magnesium alloy (content in weight %, 10 Gd, 3 Y, 0.4 Zr and Mg as balance) is PEO processed for three different metallurgical states: (i) as-extruded, (ii) T4 solution (2 h at 500 °C) and (iii) T6 peak-aged precipitation (2 h at 500 °C followed by 14 h at 225 °C). The thickest coating combined with the lowest porosity is achieved for the softest solid solution T4 treated substrate resulting in the development of a harder oxide coating. The presence of Mg(GdY)-like precipitates for the precipitating T6 condition is correlated with the appearance of cathodic micro-discharges that are known to damage the growing PEO oxide layer on magnesium. Particularly, results evidence that local segregated bands of precipitates are facing large discharge channels through the PEO coating suggesting the local ignition of strong cathodic micro-discharges. The proposed explanation consists in considering the relationship between the presence of precipitates and the isoelectric point IEP of the oxide surface with respect to the electrolyte pH. This study proves that the successful development of protective PEO coatings requires the right management of the process parameters (electrolyte chemistry, electrical conditions) together with an adequate attention to the substrate pre-treatment (mainly the metallurgical heat treatment).

Is Novamin Toothpaste Effective on Enamel Remineralization? An In-Vitro Study

Objectives: New bio-active glass containing toothpaste (NovaMin) is one of the most effective cariostatic products when used as a daily application the aim of this in-vitro study is to evaluate the influence of NovaMin on enamel remineralization.Materials and Methods: Twenty-eight sound human enamel samples were randomly divided into four groups (A-D) each having seven samples as follows: A (Novamin), B (1450 ppm NaF and Novamin), C (CPP-ACP), D (1450ppm NaF). After inducing caries-like lesions, each group was maintained daily for demineralization-remineralization cycle for seven days. During this cycle, samples were treated by the selected toothpaste for each group. Enamel mineral loss was assessed by surface microhardness. Surface enamel microhardness was determined on the enamel blocks. Non-parametric Kruskar-Wallis test compares the amount of surface microhardness recovery (SMHR%) across four different toothpastes.Results: PLM data revealed a mineral precipitation band on the surface layer of all toothpastes; however, when compared to treated lesions, no statistically significant differences among the groups (p>0.05) were found. Conclusions: NovaMin containing dentifrice has similar remineralization potential on carious-like lesions when compared to fluoride containing dentifrices.

Low-Cost, High-Performance Sample Cell for X-Ray Spectroscopy of Solutions and Gels Made from Plastic Straw.

Low-cost tube-type sample cells for X-ray spectroscopy of solutions, sols, and gels were made from plastic straws. Energy-dispersive X-ray fluorescence (XRF) experiments showed that the X-ray transparency of the straw cells is ∼50% superior to that of quartz capillary cells for 6 - 7 keV XRF and is almost uniform over the entire range, allowing its use for position-dependent measurements. Wavelength-dispersive XRF experiments showed that the difference in the surface curvature between the straw cells and pellet samples leads to an apparent ∼1.5 eV shift of the Fe Kβ1,3 peak; however, chemical effects of Fe Kβ1,3 spectra can be studied if all the samples (including standards) are evenly set in the straw cells. Additionally, the application of the straw cell in studying precipitation band formation in gels was shown on two gel samples containing 0.004 M [Fe(CN)6]3-/[Fe(CN)6]2- in 2 mass% κ-carrageenan and 0.040 M Fe2+/Fe3+ in 1 mass% agarose, respectively.