Examination Of Micrographs Research Articles

Polygonum bistorta Linn. as a green source for synthesis of biocompatible selenium nanoparticles with potent antimicrobial and antioxidant properties.

Here, we report for the first time, green-synthesized selenium nanoparticles (SeNPs) using pharmacologically potent herb of Polygonum bistorta Linn. for multiple biomedical applications. In the study, a facile and an eco-friendly approach is utilized for synthesis of SeNPs using an aqueous roots extract of P. bistorta Linn. followed by extensive characterization via Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Energy Dispersive X-Ray (EDX) analysis. The XRD and FTIR data determine the phase composition and successful capping of plant extract onto the surface of NPs while SEM and TEM micrographic examination reveals the elliptical and spherical morphology of the particles with a mean size of 69 ± 23nm. After comprehensive characterization, the NPs are investigated for antifungal, antibacterial, antileishmanial, antioxidant, and biocompatibility properties. The study reveals that Polygonum bistorta Linn. synthesized SeNPs exhibit significant antibacterial and antifungal activities with Staphylococcus aureus and Fusarium oxysporum inducing the highest zone of inhibition of 14 ± 1.0mm and 20 ± 1.2mm, respectively at the concentration of 40mg/mL. The NPs are also found to have antiparasitic potential against promastigote and amastigote forms of Leishmania tropica. Furthermore, the NPs are discovered to have excellent potential in neutralizing harmful free radicals thus exhibiting considerable antioxidant potential. Most importantly, Polygonum bistorta Linn. synthesized SeNPs showed substantial compatibility against blood cells in vitro studies, which signifies the nontoxic nature of the NPs. The study thus concludes that medicinally important Polygonum bistorta Linn. roots can be utilized as an eco-friendly, sustainable, and green source for the synthesis of pharmacologically potent selenium nanoparticles.

Investigations into mechanical properties of 50 and 70 mm thick high strength S690 butt-welded sections

A comprehensive investigation into the mechanical properties of 50 and 70 mm thick high strength S690 steel plates and their butt-welded sections under tension was presented in this paper, and a total of 40 tensile tests were conducted. Firstly, a total of 18 proportional coupons with circular cross-sections were extracted at three different layers within the plate thicknesses. Tensile tests on all of these coupons were carried out to obtain their mechanical properties, and their variations across the plate thicknesses were also examined. Secondly, submerged arc welding was adopted to prepare butt-welded sections between these thick steel plates with various heat input energy. Micrographic examinations on typical heat-affected zones of the welded sections were also performed. Standard tensile tests on a total of 22 proportional coupons with rectangular cross-sections were carried out to obtain their mechanical properties, and the full range deformation characteristics of these coupons were assessed and compared, in particular, their tensile strengths and elongations at fracture. This paper presents important experimental evidence on the mechanical properties of these high strength steel plates of practical thicknesses in construction, and also of their butt-welded sections. It is demonstrated that there is little or even no reduction in their mechanical properties of these butt-welded sections, provided that the welding processes are properly controlled according to established welding practice. Hence, full strength butt-welded sections between these thick high strength S690 steel are readily achieved in practice, similar to those of the commonly adopted S355 steel. These important findings are contrary to general understanding as many researchers and engineers consider that the mechanical properties of these high strength S690 steel are reduced significantly after welding, irrespective of their plate thicknesses.

Pressure resistance characterisation of vascular networks embedded in carbon composites for high energy physics applications

In state-of-the-art tracking detectors, lightweight carbon composite structures support the pixel or micro-strip sensors and provide the main thermal path between the silicon and a network of metallic or plastic pipes containing a cooling fluid. Despite the good results obtained with this design approach, the challenges associated with future high energy physics (HEP) experiments demand even lighter and more efficient technologies. In this regard, replacing the existing piping with a network of channels directly embedded in the composite laminates represents a promising solution to improve the thermal coupling, which also offers additional gains in terms of mass and thermo-elastic stability.While some research has been devoted to assessing the mechanical and thermal performance of such laminates, limited information about their resistance to internal pressure is currently available in the literature. This lack of data constitutes an important obstacle for the use of vascular networks in future HEP applications, which the present paper aims to address.Experimental methods were used to investigate the pressure resistance of channels embedded in carbon composite laminates. Modified poly (lactic) acid (PLA) preforms were embedded in carbon-fibre epoxy laminates. A post-cure vaporization technique removed the PLA, thus producing plates with longitudinal channels. Destructive tests were conducted to determine the burst pressure of the plates depending on the lay-up and the cross-section geometry of the channels. Both circular and oblong channels were evaluated, and various reinforcement techniques were explored to enhance the pressure resistance of the laminates. Micro-graphic examinations and X-ray micro-computed tomography were employed to gain a better understanding of the microstructure and the failure mechanisms of the plates.Plates with circular channels measuring 1.75 mm in diameter, embedded in [0/90/0]S laminates and reinforced with 2 mm lay length fuzzy carbon fibre over-braids, achieved burst pressures exceeding 45 MPa. This result, which is approximately an order of magnitude greater than that obtained for the equivalent non-reinforced laminates, demonstrates the enormous potential of this technology for future particle detectors.

Development and tribological investigation of B4C reinforced AA5082 Aluminum alloy cast composites for automotive applications

In this work, AA5082 alloy is used as base alloy to fabricate aluminum composites using fine reinforced particles of boron carbide (B4C). The conventional method of stir casting is employed for the production of composites. The particles are used with varying weight % of 5, 10, 15 and 20 for the composite fabrication. The microstructures of the composites are examined using the Scanning Electron Microscopy and x-ray Diffraction patterns. The hardness of the composites is tested and found to increase from 73 HV in base alloy to 93 HV in the AA5082 composite having B4C proportion of 15%. However, a slight decrease in hardness is also observed at higher wt% of B4C which could be due to agglomeration of particles. Evaluation of yield strength showed an escalation in the strong point with the addition of reinforced particles under the effect of orowan strengthening mechanism. Wear analysis conducted on Tribometer indicates that the escalation of load and sliding distance is proportional to the loss of material in composites whereas, wear declined with the rise of sliding speed. The micrograph examination of the wear tracks reveals the material removal mechanism from the composite as abrasive in nature. Pitting at certain places is also observed.

GMAW process with rotating electrode: an advanced alternative to improve cladding performance

This work shows that superaustenitic stainless steel weld claddings deposited by the GMAW Process with Rotating Electrode (GMAW-RE) can be a candidate to replace the GMAW process, a procedure widely applied in the industry. Single layer weld claddings were deposited by the GMAW-RE process using different rotation frequencies. After welding, macrographic analysis to determine the main geometric characteristics and micrographic examination by scanning electron microscopy equipped with energy dispersive spectrometry, and electron backscattering diffraction techniques to evaluate the microstructure were performed. The results showed that the deposits obtained by the GMAW-RE process are more homogeneous and shallow than those provided by the GMAW process. In addition, the penetration and thickness of the weld bead decreases with increasing frequency. The microstructural characterization revealed an austenitic matrix containing a low fraction of the Chi phase. These results indicate that the double layer claddings obtained by the GMAW-RE process have the potential to be an advantageous alternative for claddings because double layer deposits can achieve acceptable performance.

Effect of codoping of Zn and Ag on the spatial, optical and photocatalytic properties of cadmium oxide nanoparticles

The present article outlines the characterization of pure as well as Zn and Ag codoped cadmium oxide (CdO) nanoparticles prepared via co-precipitation method. To characterize prepared samples, X-Ray Diffraction (XRD), Diffused Reflectance Spectroscopy (DRS), Field Emission Scanning Electron Microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) studies have been carried out. From XRD spectra, it has been observed that prepared samples are crystalline in nature due to presence of sharp diffraction peaks and their crystallite size lies in the range of 20–31 nm. From DRS technique, optical bandgap has been calculated and found that incorporation of Zn and Ag decrease bandgap of prepared samples from 2.45 eV to 2.23 eV as concentration of dopants are increasing. The examination of FESEM micrographs revealed the typical shape and particle size of prepared samples. The studies of XPS spectra allow identification of elements present and their respective chemical states. To study photocatalytic property of prepared samples, Crystal Violet (CV) dye has been used with sunlight as a source of radiation. It has been observed that degradation increases as we go from pure to codoped CdO and maximum of 98% degradation was obtained after 120 min of exposure to sunlight in case of codoped CdO. The enhanced photocatalytic efficiency in case of codoped CdO suggests that prepared sample can be excellently used for water treatment applications. Scavenger test using Isopropyl alcohol (IPA) has been carried out for hydroxyl radical (•OH) and breakdown of dye molecules suggested that •OH play an important part in degradation.

Involvement of B-aat1 and Cbs in regulating mantle pigmentation in the Pacific oyster (Crassostrea gigas).

Shell color formation is an important physiological process in bivalves, the molecular genetic basis has potential application in bivalve aquaculture, but there is still remaining unclear about this issue. The cystine/glutamate transporter (Slc7a11) and cystathionine beta-synthase (Cbs) are integral genes in pheomelanin synthesis pathway, which is vital to skin pigmentation. Here, the sequences of b (0, +) -type amino acid transporter 1 (B-aat1) and Cbs in Pacific oyster (Crassostrea gigas) (CgB-aat1, CgCbs) were characterized. Phylogenetically, the deduced amino acid sequences of CgB-aat1 and CgCbs both possessed conserved features. Genes were both ubiquitously expressed in six tested tissues with more abundant expression level in central mantle. Besides, the polyclonal antibodies of CgB-aat1, CgCbs, CgTyr, and CgTyrp2 were successfully prepared. Immunofluorescence analysis revealed that CgB-aat1 and CgCbs proteins were both expressed in gill rudiments of eyed-larvae and concentrated mainly in cytoplasm of epithelial cell and nerve axons in mantle. Additionally, after CgB-aat1 or CgCbs silencing, expressions at mRNA and protein levels of CgB-aat1 and CgCbs involved in pheomelanin synthesis were significantly suppressed, and CgTyr, CgTyrp1 and CgTyrp2 related to eumelanin synthesis were also down-regulated but no apparent differences, respectively. Moreover, micrographic examination found less brown-granules at mantle edge in CgB-aat1 interference group. These results implied that pheomelanin synthesis was possible induced by CgB-aat1-CgTyr-CgCbs axis, and it played an essential role on mantle pigmentation in the oysters. These findings provide the useful genetic knowledge and enrich the physiological information for the shell color formation in bivalve aquaculture.

Gallic Acid Crosslinked Gelatin and Casein Based Composite Films for Food Packaging Applications.

In the current work, we fabricated gelatin–casein-based edible films (GC-EFs) crosslinked with gallic acid (GA). We analyzed the physiochemical characteristics, crystallinity, thermal stability, and surface properties of the EFs using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). It was found that the edible films possessed a semi-crystalline structure. Addition of GA enhanced the thermal stability of the edible films as well as the surface properties of the films. It was found that a higher concentration of GA (4–5% w/v) significantly improved the surface properties, observed in the surface and cross-sectional examination of SEM micrographs. EFs containing higher amounts of GA showed more compact and denser structures with smoother and more homogeneous surfaces than the control samples. In addition, swelling degree (SD), thickness, water solubility (WS), moisture content (MC), and water vapor permeability (WVP) were found to be low in EFs containing more GA concentration. Mechanical parameters revealed that the Young modulus (Ym) and tensile strength (TS) increased with a rise in GA concentration, and elongation at break (EB) reduced with a rise in GA concentration. In transparency and color analysis, it was observed that GA positively affected the transparency of the edible films.

Molecular characterization of Pax7 and its role in melanin synthesis in Crassostrea gigas.

The paired-box 7 (Pax7) is a transcription factor crucial for skin color polymorphism. However, the mechanism underlying the pigmentation associated with Pax7 in mollusks have yet to be elucidated. In this study, the cDNA sequence of Pax7 in the Pacific oyster Crassostrea gigas (CgPax7) was characterized. Phylogenetically, the identity of deduced amino acid sequence was similar to that of other mollusks and contained 463 amino acids, with conserved features of paired domain (PRD), homeobox domain (HD) and octapeptide. Gene expression analysis revealed that CgPax7 was markedly increased at D-shaped larvae stage and ubiquitously expressed in six examined tissues in adult oyster. The result of whole-mount in situ hybridization (WMISH) showed a restricted pattern of CgPax7 expression on margins of shell valves at D-shaped and umbo larvae stages. Additionally, although CgPax7 silencing had no significant effect on CgMitf expression, it significantly inhibited the expressions of CgPax7, CgTyr, CgTyrp1, CgTyrp2 and CgCdk2, genes involved in Tyr-mediated melanin synthesis. Furthermore, CgPax7 knockdown obviously decreased the tyrosinase activity. Less brown-granules at mantle edge was detected by micrographic examination and melanosomes defect was observed by transmission electron microscopy. It was demonstrated that CgPax7 play a key role in melanin synthesis by regulating Tyr-pathway in C. gigas. These findings indicated the potential framework by which mollusks pigmentation.

Formation and Function of the Primary Tube During Settlement and Metamorphosis of the Marine Polychaete Hydroides elegans (Haswell, 1883) (Serpulidae).

AbstractThe serpulid polychaete Hydroides elegans has emerged as a major model organism for studies of marine invertebrate settlement and metamorphosis and for processes involved in marine biofouling. Rapid secretion of an enveloping, membranous, organic primary tube provides settling larvae of H. elegans firm adhesion to a surface and a refuge within which to complete metamorphosis. While this tube is never calcified, it forms the template from which the calcified tube is produced at its anterior end. Examination of scanning and transmission electron micrographs of competent and settling larvae revealed that the tube is secreted from epidermal cells of the three primary segments, with material possibly transported through the larval cuticle via abundant microvilli. The tube is composed of complexly layered fibrous material that has an abundance of the amino acids that characterize the collagenous cuticle of other polychaetes, plus associated carbohydrates. The significance of the dependence on surface bacterial biofilms for stimulating settlement in this species is revealed as a complex interaction between primary tube material, as it is secreted, and the extracellular polymeric substances abundantly produced by biofilm-residing bacteria. This association appears to provide the settling larvae with an adhesion strength similar to that of bacteria in a biofilm and significantly less when larvae settle on a clean surface.

Anticaries activity of GERM CLEAN in Streptococcus mutans and Candida albicans dual-species biofilm.

To evaluate the antimicrobial effects of a peptide containing novel oral spray GERM CLEAN on dual-species biofilm formed by Streptococcus mutans and Candida albicans and to investigate whether GERM CLEAN inhibits the demineralization procedure of bovine enamel in vitro. The antimicrobial effects of GERM CLEAN on dual-species biofilm were analyzed by initial adherence rate calculation, water-insoluble exopolysaccharides quantification, total biomass quantification, and colony-forming units (CFUs) counting. Scanning electron microscopy and confocal laser scanning microscopy were applied to evaluate the impacts of GERM CLEAN on the biofilm structure. Further, the effects of GERM CLEAN on acidogenicity of dual-species were appraised via glycolytic pH drop analysis and hydroxyapatite dissolution measurement. The percentage of Surface Microhardness Reduction (%SMHR) evaluation, Atomic Force Micrograph (AFM) examination, and Transverse Microradiography (TMR) analysis after pH cycling were used to determine whether GERM CLEAN inhibited the demineralization of bovine enamel. GERM CLEAN decreased the adherence rate, water-insoluble EPS production, biofilm formation, and acidogenicity of the dual-species. Moreover, GERM CLEAN significantly inhibited the demineralization status of bovine enamels. This peptide containing novel oral spray GERM CLEAN has antimicrobial potential toward the dual-species. GERM CLEAN can also impede the demineralization procedure of enamel.

Antihelminthic Activity, Phytochemical Profile and Microscopic Features of Ocimum basilicum Collected in DR Congo

Aim: The main aim of the present study is to validate the bioactivity of O. basilicum, a medicinal plant traditionally used to treat helminthiasis in DRC.
 Place and Duration of Study: Department of Chemistry, Science Faculty, University of Kinshasa, between June 2018 and March 2019.
 Methodology: Different parts (stems, leaves and flowers) of O. basilicum and specimens of earthworms of Benhamia rosea were collected and identified at University of Kinshasa. Micrographic examination was carried out using Biolux NV microscope and X-ray fluorescence method for mineral content determination. Radical scavenging activity was performed using the ABTS radical test.
 Results: Microscopic analysis of O. basilicum powder revealed various histological elements like crystalline fibres, sclerotic fibres, fragments of spiral vessels, pluricellular hairs and glandular hairs. Phytochemical screening in solution and by TLC revealed the presence of polyphenols (flavonoids, anthocyanins, saponins), alkaloids, steroids, coumarins, terpenoids, irridoids and anthraquinones. 20 elements including calcium, sodium, potassium, phosphorus, magnesium, sulphur, chlorine, aluminium, manganese, iron, zinc, copper, strontium, rubidium, bromine, silver, vanadium, neodymium, silicium and lead were determined. The aqueous extract of O. basilicum showed good dose-dependent antihelminthic activity and radical scavenging activity with IC50: 27.04 ± 4.58 µg/mL.
 Conclusion: This study provides an additional information on the mineral composition and antihelminthic activity of O. basilicum growing in DRC. The antihelminthic activity of this plant could be associated to the presence of flavonoids. To the current knowledge, no study on the histological elements of O. basilicum is available in the literature.

<i>In vitro</i> Antioxidant Activity of a Nigerian Propolis and Its Investigation on Sickle Red Blood Cells

Scientific evidence suggests that antioxidants could reduce the risk of chronic diseases, including cancer and cardiovascular diseases, and play an important role in general wellbeing. Sickle cell disease (SCD) is a debilitating monogenic disorder considered as a public health problem in many countries, but with a major burden in Sub-Saharan Africa. The use of antioxidants could prove relevant and beneficial in the treatment of SCD. In this study, the antioxidant and antisickling activities of methanol extract of a Nigerian propolis were investigated. Antioxidant activity was evaluated by scavenging effect against 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical, and chelating effect against ferrous ions; ascorbic acid and thylenediamine tetraacetic acid (EDTA) were used, as standards, respectively. Antisickling activity was evaluated using a modified procedure of Emmel’s test, and phosphate buffered saline was used as a negative control. Compared to ascorbic acid (EC50 of 0.02 mg/ml), the propolis extract showed less scavenging effect (EC50 of 0.80 mg/ml) against DPPH radical. The propolis extract (EC50 of 1.84 mg/ml) also showed lower ferrous ion chelating activity compared to EDTA (EC50 of 0.29 mg/ml). In the antisickling assay, micrographic examination showed that, when treated with 1 mg/ml of the propolis extract, the morphology of the sickle red blood cells remained unaffected, thus indicating that the extract did not display antisickling effect at the concentration tested. These results indicate that the propolis extract possess moderate antioxidant activity and could be considered for possible application for its antioxidant benefits.
 Keywords: Nigerian propolis, oxidative stress, antioxidant activity, sickle cell disease, antisickling activity

Ultrastructural Characterization of Prolonged Normothermic and Cold Cerebral Ischemia in the Adult Rat.

The ultrastructural effects of prolonged normothermic and cold ischemia on the cerebral cortex of the adult rat were investigated. Complete cerebral ischemia was produced by cardiac arrest and the animals' temperature was maintained at 37°C for periods ranging from 0 to 81 hours before electron microscopy preparation. Electron micrographs of cold cerebral ischemia were generated after stabilizing the rat's temperature at 0°C after cardiac arrest for periods ranging from 0 hours to 6 months. A qualitative examination of the electron micrographs shows structural signatures of energy depletion such as vessel leaking and chromatin clumping after 1 hour at 37°C and after 24 hours at 0°C, followed by synapse degradation after 6 hours at 37°C and 1 week at 0°C. Evidence of advanced necrosis was observed after 36 hours at 37°C and 2 months at 0°C. A deep learning algorithm was introduced that demonstrates the temperature dependence of ischemia-induced ultrastructural changes and that can also successfully distinguish between early ischemic changes and advanced necrosis.

Forged products by Russian craftsmen of the 17th–19th centuries on the basis of materials from the Kikki-Akki burial ground of Upper Taz Selkups: technological characteristics

The article studies the technology of making iron and steel items of Russian origin, discovered in the Kikki-Akki burial ground of Northern Selkups (18th–19th centuries) in the north of Western Siberia in the upper reaches of the Taz River. In the study, we established the origin and chronology of Russian industrial goods in Western Siberia, as well as factors under the influence of which they appeared among the indigenous Siberian population. We examined knives and axes (17th — early 19th centuries) using the methods of metallographic analysis includ-ing macro- and micrographic examination, as well as microhardness testing. They provide an opportunity to de-termine the structure of the metal, which in turn helps determine chemical composition, physical and mechanical properties of the product. The analysis of forged products revealed that they were made according to the techno-logical traditions of Russian metalworking production existing in the 17th — early 19th centuries. Its distinctive features included the development and widespread practice in applying the modifications of two technological schemes for producing items from ferrous metal. The former was based on the welding either of iron and steel or of different grades of steel, whereas the latter involved all-steel structures. The former technological scheme pre-dominated in the production of items found in the Kikki-Akki burial ground. Moreover, the production of welded structures lacked standardisation. The following techniques were used in the production of knives: two-layer wel-ding of iron and steel, three-layer welding, V-joint welding, oblique welding, built-up welding at the ends and wel-ding of the steel blade. The use of soft quenching was noted as an additional operation that improved the opera-tional properties of the household tool. This variety of used technological schemes reflects the complex nature of the formation of the industrial goods market in Western Siberia. The selection of items made using different welded technologies is associated with the intention to use metal products of the highest quality for the fur trade and yasak collection. However, all-metal structures predominated in the main centres for the production of forged goods — cities of European Russia and Western Siberia.

Effect of Microstructure on High Cycle Fatigue and Fatigue Crack Propagation Behaviors of β-Annealed Ti–6Al–4V Alloy

High cycle fatigue (HCF) and fatigue crack propagation (FCP) behaviors of β-annealed Ti64 alloys having a microstructure of either α colonies or basketweave were studied. It was found that the resistance to HCF of β-annealed Ti64 alloys with a microstructure of α colonies was similar but slightly inferior to those with a microstructure of basketweave. On the other hand, the FCP rates of β-annealed Ti64 alloys having a microstructure of α colonies were lower than those of basketweave, particularly in low ΔK regime. Crack path observation on the surfaces of β-annealed Ti64 alloy specimens suggested that crystallographic crack growth prevailed in the microstructure of α colonies, leaving cleavage facets on the fracture surface and less fatigue damage at the tip of crack. Based on the fractographic and micrographic examination, the effects of microstructure on the HCF and FCP behaviors of β-annealed Ti64 alloys were discussed.

Simulated Heat-Affected Zone of Steel 4330V

Abstract Steel 4330V is a material that contains an addition of vanadium (approximately 0.06 wt. %). The steel is widely used in the mining and petroleum industries. The steel microstructure contains tempered martensite. The high carbon equivalent of the steel makes it difficult to weld. The simulation of the heat-affected zone (HAZ) makes it possible to determine the effect of an increase in temperature on the properties and the structure of the steel. The simulation of heating was performed using a resistive heating device. The specimens were heated between 2 and 8 s at a temperature restricted within the range of 300°C–1,300°C. During the tests, temperature was recorded using a thermal imaging camera. The tests revealed that up to a temperature of approximately 600°C, the material did not undergo structural changes. Above a temperature of 600°C, the hardness of the specimen increased to 500 HV. As the temperature of the HAZ increases, the grain size changes, which in turn affects the change of mechanical properties. Results of the impact strength tests performed at a temperature of –40°C confirmed hardness values and results of micrographic examinations.

Syntactic core composite sandwich (SCCS) with thermoplastic foam and expanded glass granulate core

Ultra light, highly porous materials arranged as a sandwich structure with thermoplastic fiber reinforced composites (TP-FRC) as a cover layer have very good physical and mechanical properties. An essential prerequisite for the production of hybrid material composites is therefore the provision of material compatible and cost effective manufacturing processes. The lightweight potential of such a syntactic core composite sandwich (SCCS) with thermoplastic and expanded glass granules was examined with the aim of a mass production. After developing a manufacturing strategy, various samples are prepared and their mechanical properties are evaluated by performing bending tests and examination of micrographs.

Cause Analysis of Turbine Shaft Ultrasonic Flaw Detection Disqualification

Heavy forging is a kind of large or deformed-size forge, used on marine, roller or power station roter. etc, which are fabricated by free forging or hydraulic compressor. The turbine shaft products, steel grade ASTM668E, rejected during ultrasonic inspection. Aiming at the problem of ultrasonic flaw detection disqualification, through Positioning saw cutting, the macroscopic test, SEM and Micrographic examination are taken out. The main cause of the disqualification were found out. The results show that, because of the exist of unbalance crystallization, highly grade general loosen happened in the cycle area, which cause the energy of ultrasonic are weakened a lot, then lead to the central quality of the forging cannot be detected clearly. What’s more, the manganese sulfide precipitated at the grain boundary because of the selective crystallization occurs in the central of the ingot. The tensile stress on the interface between steel and inclusion separate the steel, caused the cracks which couldn’t be welded as the plastic deformation happened in forging press, then cause the cracks. Reduce the molten steel’s overheat and the freezing time can improve the defect of general loosen and the gartering of low-melting ingredients. Increase the compression ratio can take out too in the hot work process to solve the problem.

Cytological Parameters of Cotton Plants under Infestation of the Two Spotted Spider Mite, Tetranychus urticae Koch (Acari: Tetranychidae)

This study was conducted to evaluate the ultrastructure and the scheme of cellular events occurring to cotton plant leaves after Tetranychus urticae infestation. Complementary information at the ultra-structural level were essential to provide further insight into the biological significance of the mite infestation. Data from the light and electron microscope examination of thin cross sections of cotton plant leaves under infestation with Tetranychus mites revealed different cytological modifications including mesophyll cell wall alteration, cytoplasm breakdown, and necrosis of cell and deformation which caused severe reductions in stomatal conductance & photosynthesis rate. Where, examination of light micrographs and ultrastructure thin cross sections of uninfested cotton plant (control) indicated the regular distributions of most cells and density in staining of most inter-cellular spaces and cell walls.