Morphology Characterization and Kinetics Evaluation of Pitting Corrosion of Commercially Pure Aluminium by Digital Image Analysis

The pit morphology and growth kinetics of commercially pure aluminium in naturally aerated NaCl solutions were studied using an image processing method based on reflected light microscopy. In order to distinguish between pits and pre-existing cavities, metallographic examination and statistical analysis were carried out before and after corrosion testing. The results show that the pit shapes and sizes are more dependent on the immersion time than the chloride concentration. Pits are predominantly hemispherical, but they undergo reasonable geometric transitions associated with increased immersion time and occur without significant depth variation. The role of chloride ions is more closely associated with the pit nucleation phenomenon.

Establishment of a three-dimensional particle library for graded crushed stone based on a new aggregate morphology characterization method

The morphology of graded crushed stone(GCS)particles has an essential influence on the performance of aggregate mixtures.The impact of particle shape is a comprehensive effect that cannot be considered separately,leading to difficulties in establishing the relationship between the mixture properties and the aggregate morphology by using laboratory methods.The discrete element method(DEM)is an effective way widely adopted to reconstruct the morphology of particles and simulate performance tests of granular materials.However,selecting limited particles characterizing a real particle-assembly for simulation is still a challenge in current research due to the inherent rich variability of particle shapes.In this study,based on the acquisition of three-dimensional(3D)aggregate shapes by using laser scanning,ellipsoid index(EDI)translating the particle shape as a function of surface area,volume,and contour length is proposed to comprehensively evaluate aggregate morphology.Further,a particle library capable of characterizing aggregate morphology distribution is established based on the statistics of the corresponding morphological characteristics of particle samples.The model reliability is validated by carrying out a series of experimental and numerical penetration tests with nine different gradations.The established particle library can be used to model aggregate mixtures and the proposed simulation framework is promising for optimizing the mixture gradation design numerically.

Comprehensive kinetostatic modeling and morphology characterization of cable-driven continuum robots for in-situ aero-engine maintenance

In-situ maintenance is of great significance for improving the efficiency and ensuring the safety of aero-engines.The cable-driven continuum robot(CDCR)with twin-pivot compliant mechanisms,which is enabled with flexible deformation capability and confined space accessibility,has emerged as a novel tool that aims to promote the development of intelligence and efficiency for in-situ aero-engine maintenance.The high-fidelity model that describes the kinematic and morphology of CDCR lays the foundation for the accurate operation and control for in-situ maintenance.However,this model was not well addressed in previous literature.In this study,a general kinetostatic modeling and morphology characterization methodology that comprehensively contains the effects of cable-hole friction,gravity,and payloads is proposed for the CDCR with twin-pivot compliant mechanisms.First,a novel cable-hole friction model with the variable friction coefficient and adaptive friction direction criterion is proposed through structure optimization and kinematic parameter analysis.Second,the cable-hole friction,all-component gravities,deflection-induced center-of-gravity shift of compliant joints,and payloads are all considered to deduce a comprehensive kinetostatic model enabled with the capacity of accurate morphology characterization for CDCR.Finally,a compact continuum robot system is integrated to experimentally validate the proposed kinetostatic model and the concept of in-situ aero-engine maintenance.Results indicate that the proposed model precisely predicts the morphology of CDCR and outperforms conventional models.The compact continuum robot system could be considered a novel solution to perform in-situ maintenance tasks of aero-engines in an invasive manner.

Multivariate Statistic Analysis of Morphology and Ecology Characters on Some Sheep Populations in China

The sheep populations were studied with Q-type Hierarchical Clustering Method, and characters of the populations were used to construct the principal component, then, the principal component values were analyzed with R-type Hierarchical Clustering Method, which might display the genetic differentiation among populations and conform to the result of the known sheep phylogenetic system in China. Characters of the populations were studied with Q-type Hierarchical Clustering Method. The elevation and average annual rainfall were found to be important characters. The ecology factor is also an important character for the breed classification.

Morpho-Physiological and Biochemical Characterization of Soybean-Associated Rhizobia and Effect of Their Liquid Inoculant Formulation on Nodulation of Host Plants in the Cameroon Cotton Fields Zone

The aim of this research was to assess the diversity of the Cameroon cotton zone in soybean associated rhizobia in order to formulate the most efficient elite inoculant to boost both the cotton and soybean production. Therefore, soybean associated rhizobia were isolated and characterized morphologically, physiologically and biochemically on YEMA culture media. For each of the two soybean varieties (Houla1 and TGX1910 14F) used, the trials were laid out in two IRAD-fields of North Cameroon (Sanguere-Paul) and Far-North (Soukoundou) respectively, under a complete randomized complete block design, the isolate formulations representing the treatments. The six isolated strains (IS1, IS2, IS3, IS4, IS5, IS6) from which seven liquid inoculant were formulated were revealed to belong to the same slow growing group of rhizobia, with a high level of tolerance to temperature, pH, and salinity, with optimum growth at respectively 28˚C, pH (7 - 9), salt (1% - 5%). Not surprisingly, root nodules were formed by both inoculated and uninoculated soybean plants. However, the most efficient soybean-rhizobia symbiosis for nodulations were isolate IS6 associated to TGX1910 14F variety, and isolate IS5 associated to Houla1variety at Sanguere-Paul. Whereas isolate M was associated to TGX1910 14F variety, Houla 1 variety had affinity with native rhizobia isolates at Soukoundou. The present results suggest the adaptability of rhizobia isolates to a particular soybean variety at a particular cotton fields zone. These findings should be taken into consideration for commercial inoculant formulation.

Morphological and molecular evidence for natural hybridization between Sorbus pohuashanensis and S. discolor (Rosaceae)

In overlapping distribution areas of Sorbus pohuashanensis and S.discolor in North China(Mount Tuoliang,Mount Xiling and Mount Baihua),Sorbus indi-viduals were found with pink fruit,which have never been recorded for the flora of China.Fourteen morphological characters combined with four chloroplast DNA markers and internal transcribed spacer(ITS)were used to analyze the origin of the Sorbus individuals with pink fruits and their relationship to S.pohuashanensis and S.discolor.PCA,SDA and one-way(taxon)ANOVA of morphological characters provided convincing evidence of the hybrid ori-gin of Sorbus individuals with pink fruits based on a novel morphological character and many intermediate characters.Haplotype analysis based on four cpDNA markers showed that either S.pohuashanensis or S.discolor were maternal parents of Sorbus individuals with pink fruits.Incongru-ence of the position of Sorbus individuals with pink fruits between cpDNA and ITS in cluster trees supported by DNA sequence comparative analysis,implying former hybridiza-tion events between S.pohuashanensis and S.discolor.Mul-tiple hybridization events between S.pohuashanensis and S.discolor might have contributed to the generation of Sorbus individuals with pink fruits.This study has provided insights into hybridization between species of the same genus in sympatric areas,which is of great significance for the study of interspecific hybridization.

Synthesis and Characterization of Hydrogels Based on Potato Starch/Poly(vinyl Alcohol)/N,N′-Methylenebisacrylamide

Several hydrogels were synthesized by free-radical polymerization in an aqueous medium based on potato starch(PS),poly(vinyl alcohol)(PVA),and N,N′-Methylenebisacrylamide(MBAm),being possible to study these hydrogels as a function of the proportion of components incorporated.In this way,the products generated from the synthesis were characterized by swelling and deswelling kinetics,the first swelling being verified with Schott and statistical models,allowing to contrast the proximity between the experimental and theoretical behavior.Additionally,water retention in soil(R%),spectroscopy(FTIR),morphological(SEM),and thermal(TGA and DSC)analysis allowing to know the intrinsic characteristics of the material,increasing in general terms the knowledge of this type of material.In this context,it was possible to verify the characteristics and effectiveness of the synthesis and crosslinking of the main components.The experimental results obtained show that the synthesized hydrogels present representative swellings consistent with kinetic and statistical models,optimal thermal stability depending on the amount of crosslinker,and excellent water retention in environments such as soil,presenting it as an excellent alternative to be used in agro-industrial applications in an eco-friendly way.

New method for fast morphological characterization of organic polycrystalline films by polarized optical microscopy

A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vacuum deposited by weak epitaxial growth（WEG） method were acquired with polarized optical microscopy（POM）. Then morphology properties including crystal grain size, distribution, relative orientation, and crystallinity were derived from these images by fitting with a transition dipole model. At last, atomic force microscopy（AFM） imaging was carried out to confirm the fitting and serve as absolute references. This method can be readily generalized to other organic polycrystalline films, thus providing an efficient way to access the large-scale morphologic properties of organic polycrystalline films, which may prove to be useful in industry as a film quality monitoring method.

A new record of a flathead fish (Teleostei: Platycephalidae) from China based on morphological characters and DNA barcoding

A new record of Platycephalus sp.1 （sensu Nakabo, 2002） was documented based on morphological characters and DNA barcoding. We collected 174 specimens of the genus Platycephalus from Chinese coastal waters of Dongying, Qingdao, Zhoushan, and Beihai. Samples were identified as Platycephalus sp. 1 morphologically. The coloration, meristic traits, and morphometric measurements are consistent with previously published records. In brief, it is an orange-brown flathead fish with dark brown spots scattered on head and body, lateral line scales 83 to 99 with one or two spine-bearing anteriormost pored scale, no yellow blotch on the caudal fin. Cytochrome oxidase I subunit （COI） gene fragments were sequenced for phylogenetic analysis. The mean evolutionary distance within the species Platycephalus sp. 1 was 0.1%. Net evolutionary distances between Platycephalus sp. 1 and other species of Platycephalus ranged from 10.8% to 19.7%, which is much greater than the threshold for species delimitation. The COl sequence analysis strongly supports the validity ofPlatyceohalus sp. 1 at genetic level.

Study on Relationship of Root Morphological Characters and Biomass of Cupressus lusitanica in Different Age Classes

[Objective] The aim was to explore biomass and growth of Cupressus lusitanica seedlings in order to provide technological supports for afforestation. [Method] The introduced Cupressus lusitanica seedlings at different ages were re- searched to explore biomass （ground or underground） morphological shape, surface area and volume of a root system. [Result] As age grew, plant height and ground diameter increased significantly, varying dramatically upon seed provenance, and root-canopy ratio, root length, surface area and volume of seedlings were increas- ing. Specifically, seedlings at two-year-old and three-year-old kept a stable growth; moderate and big roots took higher proportions in a root system; underground parts for a plant required more photosynthetic products; root systems of young seedlings grew to moderate and big roots. [Conclusion] Ground biomass is of correlation with root system indices and the morphological characteristics of root systems are close to biomass. The accumulation capacity of biomass differed for seedlings from differ- ent provenances, even in the same environment and at the same time.

A new record of Sebastes koreanus from China based on morphological characters and DNA barcoding

A new record of Sebastes koreanus （Kim and Lee, 1994） was documented based on morphological characters and DNA barcoding. Fifty-six Sebastes specimens were collected from the coastal waters of northern China. Samples were identified as S. koreanus based on morphological characters. The coloration and morphometric measurements were consistent with those described from specimens collected in South Korea. In this study, specimens had the following morphological characteristics： light brown body with dark stripes and tiny dark spots, 4-5 wide indistinct vertical patterns on the side, 2 radial stripes behind and below the eyes, 1 large dark blotch on the opercle. Additionally, the following meristie characters were recorded： dorsal fin XIV-13, pectoral fin 16, anal fin III-6-7, pelvic fin [-5, lateral line scales 29-30, and vertebrae 26. The fragment of cytochrome oxidase subunit I （CO1） gene of mitochondrial DNA was sequenced for phylogenetic analysis. The mean genetic distance within the species was 0.3%. Net genetic distances between S. koreanus and other Sebastes species ranged from 3.1% to 7.6%, which was greater than the threshold for species delimitation. The phylogenetic analysis strongly supports the validity of S. koreanus in China at the genetic level. The origion, evolution, patterns of speciation and unique features in genome divergence among primate lineages of this species still need future directions of research.

Evaluation of Sorghum (Sorghum bicolor) Landraces for Drought Tolerance Using Morphological and Yield Characters under Rainfed Conditions of Sub Region Hagaz, Eritrea

Sorghum is an important food crop in Eritrea where it is widely grown in the mid and low lands,of semi-arid regions.Eritrea being the center of ori­gin of sorghum,a large variability exist in its landraces being grown by the farmers since generations.In order to improve the productivity of sorghum under moisture stress conditions,it is imperative to evaluate these landraces for drought tolerant characteristics and their use for further crop improve­ment programmes.Therefore,a field study was conducted in a randomized complete block design with three replications to estimate the extent of genetic variability of 20 sorghum genotypes for moisture stress tolerance using various morphological,phenological,yield and yield related parame­ters under rainfed conditions at Hagaz Research Station.Significant differ­ence was observed for almost all the characters in the individual analysis of variance suggesting that these sorghum accessions were highly variable.Accessions EG 537,EG 1257,EG 849,EG 791,EG 783 and EG 813 showed promising results for post flowering drought tolerance,grain yield and stay green traits.Higher PCV and GCV were also obtained in parame­ters like plant height,leaf area,biomass,peduncle exertion,panicle length,and grain yield and panicle weight.The genotypes also exhibited varying degrees of heritability estimates.Characters such as plant height,panicle length,days to flowering and maturity showed higher heritability.Cluster analysis revealed that sorghum landraces were grouped on the basis of their morphological traits and geographical sites.77.3%of the total variation of sorghum landraces was contributed by the first four principal components analysis having Eigen value>1.Overall,the current study confirmed that EG 537,EG 849,EG 1257,EG 791,and EG 813 are drought tolerant sor­ghum landraces during post flowering stage.

The Evolution of Stinging Hairs and Other Characters in Nettle Family

Urticaceae Juss.is a large cosmopolitan family and taxonomically difficult group,partly because it encompasses a broad range of morphological diversity and many of the diagnostic characters（e.g.flower,achene.stipule,bract）require a microscope for accurate determination.Meanwhile,most Uriiceae species have stinging hairs which make them more difficult to collect and identify.As a result,the infra-familial classification of Urticaceae has been controversial for more than a century.A research group led by Prof.

Occurrence pattern and morphological polymorphism of Chinese weedy rice

Rice,the main food crop in China,has been sporadically reported to suffer from weedy rice infestation.However,the overall occurrence and distribution pattern of Chinese weedy rice remains unclear because a systematic survey has not been conducted.In order to reveal the infestation of Chinese weedy rice,a field survey was conducted in 999 sampling sites all over the rice-growing regions in China from 2009 to 2016 using seven-scale visual scoring of the level of weed infestation.Weedy rice was found 39%occurrence incidence in a total of 387 sites.The sampling sites with 50%or higher overall weedy rice infestation index mainly radiated from Jiangsu,Heilongjiang,Ningxia and Guangdong to the whole East China,Northeast China,Northwest China and South China.A total of 45 morphological characters from 287 populations(collected simultaneously with the field survey)out of those occurred sites were observed and analyzed using multivariate analysis in common gardens with the same cultivation conditions in 2017 and 2019.Canonical correlation analysis showed that 45 morphological characters were significantly related to the latitude,mean temperature,minimum temperature,precipitation and mean diurnal range factors.The 287 weedy rice populations were divided into three morphological groups with climate-dependent geographical differentiation:strong tiller type only in Jiangsu,large leaf type in South China and Central China and large grain type mainly in North China.Weedy rice seriously infested rice fields and had a geography,climate and cultivated rice type-dependent morphological and biotype differentiation in China.It is suggested to pay attention to the harmfulness of weedy rice and adopt comprehensive control strategies.

Evaluation Indicators and Extraction Method for Pitting Corrosion of Structural Steel

A set of evaluation indicators based on corrosion ratio in theory for assessing the extent of pitting corrosion and performance reduction are proposed. In order to quantify the morphology of pitting corrosion and extract the evaluation indicators,the 3D profile data obtained by pitting morphology measurement are imported into a special written program to automatically determine the location of each corrosion pit and distill any desired data pertinent to the pitting morphology. The results show that this method seems to be effective to analyze the corroded surface and characterize the pitting morphology.

Morphology-controllable synthesis and characterization of CeO_2 nanocrystals

CeO2 nanocrystals with different morphologies were synthesized by adjusting the pH value of the starting solution in water-in-oil microemulsion. The obtained samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）. thermogravimetric analysis and different thermal analysis （TGA/DTA）, Brunauer-Emmet-Teller （BET） surface area measurement, ultraviolet-visible absorption （UV-vis） spectroscopy and photoluminescence （PL） spectroscopy. Results show that the mor- phologies of CeO2 were transformed from granular to spherical and to rod-like while the pH of the starting solution varied from 5 to 8 and to 11. All samples were indexed to the phase of Ce02 and Ce（OH）4, and the molar ratio of Ce02 to Ce（OH）4 was deduced to be about 0.25, The morphologies of CeO2 nanocrystals had but slight influence on their specific surface areas, UV-vis spectra and PL spectra, The band gap energies of different morphological samples were estimated by UV-vis spectroscopic method,

GC-MS analysis of volatile compounds of Perilla frutescens Britton var. Japonica accessions: morphological and seasonal variability

Objective: To investigate the composition of volatile compounds in the different accessions of Perilla frutescens(P. frutescens) collected from various habitats of China and Japan. Methods: In the present study, the essential oil from the leaves of P. frutescens cultivars from China and Japan was extracted by hydro-distillation and the chemical composition and concentration of the volatile components present in the oils were determined by gas chromatography–mass spectrometry(GC–MS) analysis. Results: Among the volatile components, the major proportion was of perilla ketone, which was followed by elemicin and beta-caryophyllene in the Chinese Perilla cultivars. The main component in the oil extracted from the Japanese accessions was myristicin, which was followed by perilla ketone and beta-caryophyllene. We could distinguish seven chemotypes, namely the perilla ketone(PK) type, perilla ketone, myristicin(PM) type, perilla ketone, unknown(PU) type, perilla ketone, beta-caryophyllene, myristicine(PB) type, perilla ketone, myristicin, unknown(PMU) type, perilla ketone, elemicine, myristicin, beta-caryophyllene(PEMB) type, and the perilla ketone, limonene, betacryophyllene, myristicin(L) type. Most of the accessions possessed higher essential oil content before the flowering time than at the flowering stage. The average plant height, leaf length, leaf width of the Chinese accessions was higher than those of the Japanese accessions. Conclusion:The results revealed that the harvest time and geographical origin caused polymorphisms in the essential oil composition and morphological traits in the Perilla accessions originating from China and Japan. Therefore, these chemotypes with desirable characters might be useful for industrial exploitation and for determining the harvest time.

Correlation and Path Coefficient Analyses in Sugarcane Genotypes of Ethiopia

To study the relations of certain morphological and sugar quality characters with sugarcane yield, an experiment was conducted at Wonji and Metehara Sugar Estates, Ethiopia between March 2012 and October 2013. The experiment, comprising of 400 sugarcane genotypes of which 174 were local that were collected from different regional states of Ethiopia and 226 introduced, was laid out in partial balanced lattice design with two replications. Data was collected on cane yield and its components, sugar yield and sugar quality traits. ANOVA, correlation and path coefficient analysis were done. Analysis of variance revealed significant differences (P < 0.01) for all the characters studied. Cane yield showed strong positive and highly significant (P < 0.01) correlation with millable cane number (r = 0.832), single cane weight (r = 0.528), stalk height (r = 0.517) and sugar yield (r = 0.987). There was also positive significant (P = 0.05) correlation of tiller count and cane diameter with cane yield. Path analysis revealed the highest positive direct effect of millable cane number (0.812) on cane yield followed by single cane weight (0.682) and pol percent (0.550). However, stalk diameter and brix percent had considerable negative direct effects and indirect positive effects through single cane weight on cane yield. Therefore, in view of their significant positive association with cane yield, indirect effects of stalk diameter and brix percent via single cane weight should be considered during selection. Genotypes should be selected on the basis of millable cane number, single cane weight and pol percent for getting higher cane and sugar yield.

Identity and distribution of weedy Pedicularis kansuensis Maxim. (Orobanchaceae) in Tianshan Mountains of Xinjiang：morphological, anatomical and molecular evidence

Weedy plants affect the biodiversity and ecosystem function as well as the crop and fodder plant production. However, adequate management requires detailed knowledge of the taxonomic identity of these plants. Here, we focused on a hemiparasitic Pedicularis species（Orobanchaceae）, which occurs at high densities and results in significant biomass reductions in forage grasses in Bayanbulak Grassland of Xinjiang. The identity of this target species is not clear, with conflicting reports in publications and in herbarium collections. Hence, clear and management-relevant information on demography and reproductive ecology is difficult to be obtained from the literature. Therefore, we analyzed field and archival materials collected from Xinjiang in order to clarify the identity and distribution of the target species. Morphological analyses suggested that the populations at Bayanbulak Grassland should be Pedicularis kansuensis Maxim. rather than P. verticillata L. which has been accepted in the available literature. Phylogenetic analysis with a combination of three barcodes（mat K, rbc L and trn H-psb A） uniting a clade of P. kansuensis and individuals from Bayanbulak Grassland populations with 100% bootstrap support, confirmed the target species to be P. kansuensis. Anatomical investigations and field observations showed that the target species is an annual or biennial herb, which also fits with the life cycle as P. kansuensis. Based on archive material and field observations, we verified that the distribution of P. kansuensis is mainly concentrated in the Tianshan Mountains of Xinjiang.

Morphological and Genetical Variability among Rhizoctonia solani Isolates Causing Sheath Blight Disease of Rice

Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a reference isolate confirmed that all the isolates belonged to R. solani. Significant variation was observed in sclerotial size, shape and distribution. Un-weighted pair group method with arithmetic mean dendrogram constructed based on the Gower＇s general similarity coefficient showed that these isolates were grouped into four clusters at the 0.68 similarity coefficent according to morphological characters. Cluster I was a major cluster consisting of 13 isolates, while clusters Ⅱ to Ⅳ consisted of 1 or 2 isolates. Analyses by variable number of tandem repeat and amplified fragment length polymorphism markers showed that the isolates were grouped into five and three clusters at a similarity coefficient of 0.64 and 0.69, respectively. Although most of the variability was found between isolates from different regions as expected, significant variation was observed within the isolates collected from similar agro-ecological regions. Our results suggest the presence of different races of R. solani within the same local geographic regions.