Utilizing sediment grain size characteristics to assess the effectiveness of clay–sand barriers in reducing aeolian erosion in Minqin desert area,China

The clay–sand barriers in Minqin desert area,China,represent a pioneering windbreak and sand fixation project with a venerable history of 60 a.However,studies on evaluating the long-term effectiveness of clay–sand barriers against aeolian erosion,particularly from the perspective of surface sediment grain size,are limited and thus insufficient to ascertain the protective impact of these barriers on regional aeolian activities.This study focused on the surface sediments(topsoil of 0–3 cm depth)of clay–sand barriers in Minqin desert area to explain their erosion resistance from the perspective of surface sediment grain size.In March 2023,six clay–sand barrier sampling plots with clay–sand barriers of different deployment durations(1,5,10,20,40,and 60 a)were selected as experimental plots,and one control sampling plot was set in an adjacent mobile sandy area without sand barriers.Surface sediment samples were collected from the topsoil of each sampling plot in the study area in April 2023 and sediment grain size characteristics were analyzed.Results indicated a predominance of fine and medium sands in the surface sediments of the study area.The deployment of clay–sand barriers cultivated a fine quality in grain size composition of the regional surface sediments,increasing the average contents of very fine sand,silt,and clay by 30.82%,417.38%,and 381.52%,respectively.This trend became markedly pronounced a decade after the deployment of clay–sand barriers.The effectiveness of clay–sand barriers in erosion resistance was manifested through reduced wind velocity,the interception of sand flow,and the promotion of fine surface sediment particles.Coarser particles such as medium,coarse,and very coarse sands predominantly accumulated on the external side of the barriers,while finer particles such as fine and very fine sands concentrated in the upwind(northwest)region of the barriers.By contrast,the contents of finest particles such as silt and clay were higher in the downwind(southeast)region of the sampling plots.For the study area,the deployment of clay–sand barriers remains one of the most cost-effective engineering solutions for aeolian erosion control,with sediment grain size parameters serving as quantitative indicators for the assessment of these barriers in combating desertification.The results of this study provide a theoretical foundation for the construction of windbreak and sand fixation systems and the optimization of artificial sand control projects in arid desert areas.

CHARACTERISTIC GRAIN SIZE: PART Ⅱ MEASURING PRINCIPLES

The principles for measuring characteristic grain sizes of materials, such as fully-dense single phase materials, porous materials and materials with isolated second phase particles, are developed on the basis of its definition associated closely with the surface area per unit volume, Sv, of grain. The focus of the measuring principles of the characteristic grain size is put on determining Sv of grains. Unlike the measurement of average grain size commonly used, G, correcting factors such as grain shape and grain size distribution factors, will not be applied to the determination of the characteristic grain size, Gc, due to its unique geometric meaning and the measure precision of Sv being guaranteed by quantitative stereological technique and gas adsorption method. The measurement of Gc can be directly carried out on the polished and etched cross section of materials, similar to the measuremernt of the average grain size using the Heyn intercept method.

Correlation Study on Grain Size Characteristics and Geotechnical Properties of Surface Sediments in Qingdao Offshore Area

The comprehension of sediment grain size parameters and the corresponding sedimentary environment holds paramount importance in elucidating the engineering geological attributes of the subaqueous seabed.This study delineated the sedimentary environment zoning in the northern sea area of Qingdao through cluster analysis of grain size parameters derived from 123 surface sediment samples.The study analyzed the correlation between sediment geotechnical indices and grain size parameters across diverse sedimentary environments.A correlation equation was established for samples exhibiting a strong correlation.The study found four distinct sedimentary environments in the study area:coastal,transitional,shallow sea,and residual.Within the same sedimentary environment,the average grain size and sorting coefficient exhibit significant correlations with geotechnical indices such as water content,density,shear strength,plastic limit,liquid limit,and plastic index.However,notable disparities in the correlation between grain size parameters and geotechnical indices emerge across different sedimentary environments.

Effect of Skeleton Grain Size on the Saturation of Gas Hydrate in Natural Sediments

Natural gas hydrate is prospected as a new and promising,highly clean energy resource that mainly occurs in perma-frost or at continental margins.Its formation is subject to many soil conditions,such as grain size,matrix materials,pore morphology,and permeability.In this study,we propose that grain size is the most decisive parameter that affects the saturation of gas hydrate in sediments based on data from Ocean Drilling Program Leg 164 and Mallik 5L-38,which represent marine sediments and terrestrial sediments,respectively.Our study reveals that high gas hydrate saturation generally occurs in coarse-grained sand,regardless of whether sediment formation is homogeneous or inhomogeneous,and the sorting of sediments may affect the hydrate saturation to a certain degree.Using grain size and sorting of sediments may be the most intuitive proxy method for a rough estimation of hydrate saturation.Further study is necessary to fully understand the relationship between hydrate morphology and sediment grain size,even though massive hydrates are typically found in fine clayey-rich sediments.

Application of Hooke &Jeeves Algorithm in Optimizing Fusion Zone Grain Size and Hardness of Pulsed Current Micro Plasma Arc Welded AISI 304L Sheets

AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The paper focuses on developing mathematical models to predict grain size and hardness of pulsed current micro plasma arc welded AISI 304L joints. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical models have been developed by Response Surface Method (RSM) and its adequacy is checked by Analysis of Variance (ANOVA) technique. By using the developed mathematical models, grain size and hardness of the weld joints can be predicted with 99% confidence level. The developed mathematical models have been optimized using Hooke and Jeeves algorithm to minimize grain size and maximize the hardness.

Natural variation of an autophagy-family gene among rice subspecies affects grain size and weight

Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding varieties.We identified a novel gene,GW3a(Grain Weight 3a)(LOC_Os03g27350),that affects rice grain size and weight.gw3a mutants showed higher total starch content and dry matter accumulation than the wild type(WT),Nipponbare,suggesting that GW3a negatively regulates grain size and weight.Moreover,our study found that GW3a interacted with OsATG8 by cleaving it,suggesting that GW3a may be involved in the assembly of autophagosomes and starch degradation in plants.The haplotype analysis of GW3a showed functional differences between indica and japonica rice.Taken together,we conclude that GW3a is expressed in the autophagosome pathway regulating starch metabolism in rice,affecting yield-related traits,such as grain size,grain weight and thousand grain weight(TGW).Our findings also shed new light on autophagy-mediated yield trait regulation,proposing a possible strategy for the genetic improvement of high-yield germplasm in rice.

Rice AGL1 determines grain size and sterile lemma identity

The grass spikelet is a unique inflorescence structure that determines grain size.Although many genetic factors have been well characterized for grain size and glume development,the underlying molecular mechanisms in rice are far from established.Here,we isolated rice gene,AGL1 that controlled grain size and determines the fate of the sterile lemma.Loss of function of AGL1 produced larger grains and reduced the size of the sterile lemma.Larger grains in the agl1 mutant were caused by a larger number of cells that were longer and wider than in the wild type.The sterile lemma in the mutant spikelet was converted to a rudimentary glume-like organ.Our findings showed that the AGL1(also named LAX1)protein positively regulated G1 expression,and negatively regulated NSG1 expression,thereby affecting the fate of the sterile lemma.Taken together,our results revealed that AGL1 played a key role in negative regulation of grain size by controlling cell proliferation and expansion,and supported the opinion that rudimentary glume and sterile lemma in rice are homologous organs.

Characterization and mapping of QTLs on chromosome 2D for grain size and yield traits using a mutant line induced by EMS in wheat

Production of mutants with altered phenotypes is a powerful approach for determining the biological functions of genes in an organism. In this study, a high-grain-weight mutant line M8008 was identified from a library of mutants of the common wheat cultivar YN15 treated with ethylmethane sulfonate(EMS). F2 and F2:3generations produced from crosses of M8008 × YN15(MY) and M8008 × SJZ54(MS) were used for genetic analysis. There were significant differences between M8008 and YN15 in plant height(PH), spike length(SL),fertile spikelet number per spike(FSS), grain width(GW), grain length(GL), GL/GW ratio(GLW), and thousand-grain weight(TGW). Most simple correlation coefficients were significant for the investigated traits, suggesting that the correlative mutations occurred in M8008. Approximately 21% of simple sequence repeat(SSR) markers showed polymorphisms between M8008 and YN15, indicating that EMS can induce a large number of mutated loci. Twelve quantitative trait loci(QTLs) forming QTL clusters(one in MY and two in MS) were detected. The QTL clusters coinciding with(MY population) or near(MS population) the marker wmc41 were associated mainly with grain-size traits, among which the M8008 locus led to decreases in GW, factor form density(FFD), and TGW and to increases in GLW. The cluster in the wmc25–barc168 interval in the MS population was associated with yield traits, for which the M8008 locus led to decreased PH, spike number per plant(SN), and SL.

Observations on the Formation of Ultrafine Ferrite Grain Size in Steels by Physical Simulation Routes

Some observations are reported on the simulation of two thermomechanical routes to produce ultrafine ferrite grainsize in steels. One C-Mn grade and Nb, Nb-Ti and Nb-high Ti bearing steels were used in the tests performed ona Gleeble simulator and a laboratory rolling mill. The routes included severe hot deformation of prior grain-refinedaustenite at the temperature close to Ar3 (DIF) and static recrystallization of fine-grained cold-rolled martensite(SRM). It was observed that the hot deformation induces the formation of ferrite above the Ar3 temperature of thesteel, but severe reductions are required for the complete transformation. Strain of 1.2 can result in about 70% offerrite with the grain size of about 1.4～2μm in all the studied steels. Similarly, in short annealing of cold-workedmartensite, the static recrystallization can also lead to a grain size of about 1.5 μm. The distribution of carbonvaries in the microstructures, carbon being in the second phase in the DIF route and in carbide particles in the SRMroute, which may have a significant influence on the mechanical properties and the thermal stability of ultrafine grainstructure.

Mapping and genetic validation of a grain size QTL qGS7.1 in rice(Oryza sativa L.)

Grain size is a major determinant of grain weight, which is one of the components of rice yield. The objective o this study was to identify novel, and important quantitative trait loci(QTLs) for grain size and weight in rice. QTLs were mapped using a BC4F4 population including 192 backcross inbred lines(BILs) derived from a backcross between Xiaolijing(XLJ) and recombinant inbred lines(RILs). The mapping population was planted in both Lingshui(Hainan, 2015) and Fuyang(Zhejiang, 2016), with the short-and long-day conditions, respectively. A total of 10 QTLs for grain length, four for grain width, four for the ratio of grain length to width, and 11 for grain weight were detected in at least one environment and were distributed across 11 chromosomes. The phenotypic variance explained ranged from 6.76–25.68%, 14.30–34.03%, 5.28–26.50%, and 3.01–22.87% for grain length, grain width, the ratio of grain length to width, and thousand grain weight, respectively. Using the sequential residual heterozygotes(SeqRHs) method, qGS7.1, a QTL for grain size and weight, was mapped in a 3.2-Mb interval on chromosome 7. No QTLs about grain size and weight were reported in previous studies in this region, providing a good candidate for functional analysis and breeding utilization.

Assessment of the Relationship between ESR Signal Intensity and Grain Size Distribution in Shear Zones within the Atotsugawa Fault System, Central Japan

For the first time, a relationship between ESR signal intensity and grain size distribution (sieve technique) in shear zones within the Atotsugawa fault system have been investigated using fault core rocks. The grain size distributions were estimated using the sieve technique and microscopic observations. Stacks of sieves with openings that decrease consecutively in the order of 4.75 mm, 1.18 mm, 600 μm, 300 μm, 150 μm and 75 μm were chosen for this study. Grain size distributions analysis revealed that samples further from the slip plane have larger d50 (average gain size) (0.45 mm at a distance of 30 - 50 mm from the slip plane) while those close to the slip plane have smaller d50 values (0.19 mm at a distance of 0 - 10 mm from the slip plane). This is due to intensive crushing that is always associated with large displacement during fault activities. However, this pattern was not respected in all shear zones in that, larger d50 values were instead observed in samples close to the slip plane due to admixture of fault rocks from different fault activities. Results from ESR analysis revealed that the relatively finer samples close to the slip plane have low ESR signals intensity while those further away (coarser) have relatively higher signal intensity. This tendency however, is not consistence in some of the shear zones due to a complex network of anatomizing faults. The variation in grain size distribution within some of the shear zones implies that, a series of fault events have taken place in the past thus underscoring the need for further investigation of the possibility of reoccurrence of faults.

Association Mapping of Quantitative Trait Loci for Grain Size in Introgression Line Derived from Oryza rufipogon

Grain size is one of the critical agronomic traits governing grain yield and quality in rice.However,the underlying genetic mechanisms that control grain size in rice are poorly understood.We used an introgression line derived from Zhonghui 8015 and Oryza rufipogon Griff.This introgression line was evaluated under two different environmental conditions to dissect the quantitative trait loci controlling grain size.Genome-wide association study(GWAS)was performed using 28193 SNPs through a general linear model,and 56 significant SNPs on different loci associated with the 4 grain size traits were detected.Cloned genes including GS3 and q GL3 showed substantial effects on grain length and size.Seven new stable loci were identified with pleiotropic effects on grain size.Haplotype,gene expression analyses,combined gene-based associations,and functional annotations permitted the shortlisting of important dominant genes including GS3 and q GL3.

Micromagnetic studies of perpendicular recording FePt media with controllable grain size distributions

A 3-dimensional (3D) micromagnetic model combined with Fast Fourier Transform (FFT) method was built up to study the writability in the L10 FePt perpendicular medium. The effects of controllable grain size distributions were studied by grain growth simulation. It is found that the cross-track-averaged magnetization changes little between the L10 FePt medium with uniform or non-uniform grain size distribution.

Effect of grain size on gas bubble evolution in nuclear fuel:Phase-field investigations

Numerous irradiation-induced gas bubbles are created in the nuclear fuel during irradiation, leading to the change of microstructure and the degradation of mechanical and thermal properties. The grain size of fuel is one of the important factors affecting bubble evolution. In current study, we first predict the thermodynamic behaviors of point defects as well as the interplay between vacancy and gas atom in both UO_(2) and U_(3)Si_(2) according to ab initio approach. Then, we establish the irradiation-induced bubble phase-field model to investigate the formation and evolution of intra-and inter-granular gas bubbles. The effects of fission rate and temperature on the evolutions of bubble morphologies in UO_(2) and U_(3)Si_(2) have been revealed. Especially, a comparison of porosities under different grain sizes is examined and analyzed. To understand the thermal conductivity as functions of grain size and porosity, the heat transfer capability of U_(3)Si_(2) is evaluated.

DUCTILEBRITTLETRANSITION OF POLYCRYSTALLINE Ni_3Al WITH VARYING GRAIN SIZE

It is known that in B (un)doped Ni 3Al polycrystals, the dependence of yield strength on grain size follows the Hall Petch relationship: σ y= σ 0+ K y d -1/2 , and the slope K y can be reduced by B doping owing to the lowering of grain boundary resistance to slip transmission. If the intergranular cracking in polycrystalline Ni 3Al occurs from the microcavity along the grain boundaries, the effective external tensile stress for the propagation of the crack like microcavity along the grain boundaries can be deduced as: σ f= σ i+ K u d -1/2 , where K u reflects the effects of such factors as environment, strain rate, boron doping and the orientation of the grain boundary on the trend of intergranular cracking. For loaded polycrystalline Ni 3Al, it should be competitive between the intergranular cracking and slip transmission across the grain boundary. Therefore, comparing the varieties of both σ y and σ f with grain size, the dependence of ductile brittle transition on grain size, and the effects of the above factors on ductile brittle transition can be expected. The model also predicts that there exists a critical grain size for the ductile brittle transition of polycrystalline Ni 3Al alloys, and B doping can increase the critical grain size due to the reduction of the slope K y and the increase of K u. The reported experimental results verified the above model.

Effects of initial grain size and strain on grain boundary engineering of high-nitrogen CrMn austenitic stainless steel

18 Mn18 Cr0.5 N steel with an initial grain size of 28–177 μm was processed by 2.5%–20% cold rolling and annealing at 1000°C for 24 h,and the grain boundary character distribution was examined via electron backscatter diffraction.Low strain(2.5%) favored the formation of low-Σ boundaries.At this strain,the fraction of low-Σ boundaries was insensitive to the initial grain size.However,specimens with fine initial grains showed decreasing grain size after grain boundary engineering processing.The fraction of low-Σ boundaries and the(Σ9 + Σ27)/Σ3 value decreased with increasing strain; furthermore,the specimens with fine initial grain size were sensitive to the strain.Finally,the effects of the initial grain size and strain on the grain boundary engineering were discussed in detail.

GL9 from Oryza glumaepatula controls grain size and chalkiness in rice

Grain size is a key factor influencing grain yield and appearance quality in rice.We identified twelve quantitative trait loci(QTL)for grain length(GL),nine for grain width(GW),and nine for 1000-kernel weight(TKW)using GLU-SSSLs,which are single-segment substitution lines with Oryza glumaepatula as donor parent and Huajingxian 74(HJX74)as recipient parent.Among the QTL,qGL1-2,qGL1-4,qGL9-2,qGW2-2,qGW9-1 and qTKW9-2 contributed to high grain yield.GL9 was identified as a candidate gene for qGL9-2 by map-based cloning and sequencing,and is a novel allele of GS9.The kernel of NIL-gl9was slenderer and longer than that of HJX74,and the TKW and grain yield per plant of NIL-gl9 were higher than those of HJX74.The proportion of grain chalkiness of NIL-gl9 was much lower than that of HJX74.Thus,gl9 increased grain yield and appearance quality simultaneously.Three pyramid lines,NIL-gs3/gl9,NIL-GW7/gl9 and NIL-gw8/gl9,were developed and the kernel of each was longer than that of the corresponding recipient parent lines.The gl9 allele may be beneficial for breeding rice varieties with high grain yield and good appearance quality.

Revealing the grain size dependent hot workability and deformation mechanisms in a Mg-Zn-Y alloy

Despite the industrial significance of grain size for enhancing mechanical properties and formability,the in-depth deformation mechanisms at elevated temperature are still unclear.To investigate the functions of grain size on hot workability and deformation mechanisms,three groups of Mg-1.2Zn-0.2Y alloy specimens with different grain sizes were hot compressed and then studied by combining constitutive model,processing map and microstructural observations.The results showed that the enhanced hot workability accompanying low deformation activation energy and small instability regime was obtained with refined grain size.During hot deformation,the decreased grain size in Mg1.2Zn-0.2Y alloy mainly improved the plastic deformation homogeneity,especially for the weakened local straining around grain boundaries.As a result,the dynamic recrystallization nucleation and texture development at lower strain level were influenced by the initial grain size.At higher strain magnitude,the growth and coarsening of dynamic recrystallized grains would further release strain localization and improve hot workability,while the texture was less impacted.Further,unlike the primary basal slip and deformation twinning in the specimen with coarse grain at low temperature,non-basal slips of dislocations were initiated with less deformation twins in the specimens with refined grain size.

Change in Grain-Size Composition of Lignite under Cyclic Freezing-Thawing and Wetting-Drying

The paper presents the change in grain-size composition of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article shows that in the spring and autumn periods the lignites can be subjected to repeated freezing-thawing and wetting-drying, which determines the possibility of changing their grain-size composition and structure. Experimental studies in laboratory conditions on the influence of cyclic freezing-thawing (FTC) and wetting-drying (WDC) on the quality indicators of lignites have been carried out, their granulometric (fractional) composition has been studied. Freezing-thawing cycle conditions are as follows (FTC): minimum exposure temperature: -20°C;maximum: +5°C;relative humidity: 30%;number of processing cycles: 3. Wetting-drying cycles are as follows (WDC): drying temperatures are +20, +40, +60, +80°C, drying time 90 minutes, the coals are further subjected to rain (soaking) for a period of water saturation to humidity of 30% - 40% and dry again. The number of wetting-drying cycles is 3 times. The tests have revealed the destructive effects of FTC and WDC on the samples of lower metamorphic grade coal, and the cycles of wet-dry lead to the much higher yield of fine sizes (-6+0;-13+0 mm) than the cycles of freeze-thaw. Furthermore, it is found that the increase in the yield of fines depends on the heating temperature: coal disintegration proceeds more intensively at a higher temperature of drying.

The Effect of Grain Size on the Viscosity and Yield Stress of Fine-Grained Sediments

In debris flow modelling,the viscosity and yield stress of fine-grained sediments should be determined in order to better characterize sediment flow.In particular,it is important to understand the effect of grain size on the rheology of fine-grained sediments associated with yielding.When looking at the relationship between shear stress and shear rate before yielding,a high-viscosity zone(called pseudoNewtonian viscosity) towards the apparent yield stress exists.After yielding,plastic viscosity(called Bingham viscosity) governs the flow.To examine the effect of grain size on the rheological characteristics of fine-grained sediments,clay-rich materials(from the Adriatic Sea,Italy; Cambridge Fjord,Canada; and the Mediterranean Sea,Spain),silt-rich debris flow materials(from La Valette,France) and silt-rich materials(iron tailings from Canada) were compared.Rheological characteristics were examined using a modified Bingham model.The materials examined,including the Canadian inorganic and sensitive clays,exhibit typical shear thinning behavior and strong thixotropy.In the relationships between the liquidity index and rheological values(viscosity and apparent yield stress),the effect of grain size on viscosity and yield stress is significant at a given liquidity index.The viscosity and yield stress of debris flow materials are higher than those of low-activity clays at the same liquid state.However the viscosity and yield stress of the tailings,which are mainly composed of silt-sized particles,are slightly lower than those of low-activity clays.