Influence of the Distribution of Excess Carbide on the Properties of Genuine Damascus Steel

The methods of spectral, x-ray phase and microprobe analysis show that genuine Damascus steel is a high-purity unalloyed high-carbon steel with a high phosphorus content. It is shown that phosphorus in an amount of from 0.1% to 0.2%, having a high liquation coefficient, contributes to the process of segregation of carbon in interdendritic zone in the process of crystallization. Interdendritic zone formed carbon clusters, in the process of forging transform into oblong carbides cementite. The main physical and chemical factors affecting the formation of oblong carbides are revealed. The hardness of carbide layers was determined, which was about 920 HV. The hardness of the troostite matrix was amounted about 475 HV. It is established that the cutting edge of the blade knife of Damascus steel is nothing more than a “micro-saw” consisting of parallel carbide and troostite layers. Tests are conducted on the preservation of the cutting edge sharpness of the blades knife of homogeneous structure of steel У15А (Russian) and the layered structure of genuine Damascus steel Ds15P (Indo-Persian). Found that with little effort cut (to 4 kg) ancient Damascus steel (Ds15P) shows a greater number of cuts than the modern instrument steel У15А. With an increase, force on the cutting edge from 6 kg to 12 kg carbon Tool steel is showed a more number of cutting on the 25% than in genuine Damascus steel. The fatigue crack propagation in the true Layered structure of Damascus steel Ds15P occurs for a greater number of cycles than in a homogeneous structure of the steel У15А. The blade knife of genuine Damascus steel, in terms of fatigue reliability (survivability), has almost 2 times longer service life than the blade knife of the modern carbon tool steel type У15А. It is proved that loss in cutting ability of a genuine Damascus steel compensates increased the reliability (“survivability”) of the blade knife with fatigue loads.

Soybean lecithin-based extender improves Damascus goat sperm cryopreservationand fertilizing potential following artificial insemination

Objective: To study the effect of adding different concentrations of soybean lecithin in Tris based extender and to compare the results of Tris soybean lecithin extender with two commercial diluents (egg yolk-based: BullXcell and plant-based: OptiXcell) for Damascus goat sperm cryopreservation. Methods: The ejaculates from 4 mature male Damascus goats were obtained by using an artificial vagina. Semen samples were pooled and diluted in Tris extender supplemented with soybean lecithin at different concentrations of 1.5%, 3.0%, 6.0% and 10.0% to get better concentration to be used for further experiments, with a final concentration of 240×106 spermatozoa/mL. Semen samples were packed in straws (0.25 mL), frozen by using an automated system and stored in liquid nitrogen at -196 ℃ for 48 h. After thawing (37 ℃/30 s), the samples were evaluated for sperm quality parameters, including sperm motility, membrane integrity and acrosome integrity. Malondialdehyde concentration was estimated as a marker for lipid peroxidation. Based on the previous investigations, only Tris extender supplemented with 3.0% soybean lecithin (based on its positive results) was used versus BullXcell and OptiXcell for sperm ultrastructure evaluation and artificial insemination by using electron microscope and artificial insemination of the synchronized does. Results: There was no significant difference between Tris-soybean lecithin at 3.0% and BullXcell/OptiXcell diluents in post-thaw sperm parameters and fertility following artificial insemination;meanwhile, the other concentrations of soybean lecithin (1.5%, 6.0% and 10%) showed lower sperm parameters following cryopreservation. Conclusions: Using of Tris-soybean lecithin based extender at the level of 3.0% can be an appropriate alternative to either BullXcell or OptiXcell for Damascus goat sperm cryopreservation.

Influence of Morphology Pattern of Genuine Damascus Steel on the Nature of Relief of Fracture Surfaces

It has been revealed that the structure of the transverse and longitudinal parts of the genuine Damascus knife of the XVIII century consists of troostite-carbide of the banding. The microhardness of the troostite layers is 450 HV;the carbide layers reach 950 HV. It is shown that such a banding structure in hardness will have a huge impact on the formation of a naturally patterned genuine Damascus structure. It is established that the form of the main drawings of the genuine Damascus pattern consists of separate elements of the topographic contour: hollows, hills, saddles, crosses and wavy dunes. It is shown that the damask pattern is a set of individual elements of the macrostructure alternating in a disordered form on different local areas of the surface. It is established that the destruction of genuine Damascus steels occurs under the action of two or more mechanisms, during the implementation of which traces remain on the surface of the fractures in the form of relief details of a mixed type. The mechanisms of mixed destruction are a combination of intragrain cleavage, micropore fusion and intergrain cracking. It is established that in order to implement the mechanism of separation of the main crack in the direction of the chopping blow, an optimum is required in the dispersion of troostite (61.8%) and carbide (38.2%) layers in genuine Damascus steel, the ratio of their volumes obeys the golden section rule. It is established that the damask pattern, consisting of elements of sinuous lines of a topographic contour, does not significantly affect the level of mechanical properties. This factor is a category of the quality of banding structures in genuine Damascus steel.

Morphology of quarters in traditional Arab Islamic city:A case of the traditional city of Damascus

Studies on the quarters of traditional Arab Islamic cities have stressed the idea of an urban structure that corresponds to social groupings and to a collection of local regions or even of,,inchoateM neighborhood units.This spatial model has often provided the rationale for the intervention in these cities and in the design of new housing layouts.This study aims to examine this issue through syntactic measures and observations to describe and analyze the structure and morphology of quarters through connectivity and visibility analysis of pedestrian move ment through space syntax.Whether the structure of these cities presents a global whole in contrast to the assumptions of physical subareas of social groupings is discussed.The city of Damascus is used as a model of analysis in which the urban morphology of quarters is described and characterized.This study reports several findings that are potentially relevant to the understanding of traditional laws that relate the physical layout of quarters to the social structure and their local subareas to the global whole that dominate and unify the parts.On this basis,the design approach in these cities may be better understood.

Formation of Eutectic Carbides in the Structure of High-Purity White Cast Iron in the Forging Process

It is found that the deformation of white cast iron under forging production is only possible with a minimum number of permanent impurities. The developed modes of high-temperature intermediate annealing facilitate the deformation of the forging under normal production conditions. It is shown that in the process of isothermal annealing of white cast iron begins the process of disintegration of ledeburite in the more stable eutectic carbides, providing technological plasticity for subsequent forging. The installed influence of the purity of white cast iron on the morphology of the excess carbides and their ability to divide. Studies the morphology of the excess eutectic carbides after melting, pre-annealing and after deformation forging. Discovered that after severe plastic deformation the structure of white cast iron becomes more stable, due to the appearance of eutectic carbides. It was determined that the deformed structure of white iron, because of its lack ledeburite component, was more identical with the structure of the alloy ledeburite steels. The data obtained can be used for making Damascus bladed weapons products, experiencing shock-variables loads.

Wootz: Cast Iron or Steel?

It is shown that the excess carbide phase in Wootz is of an unusual nature origin that differs from the excess phase of secondary cementite, ledeburite and primary cementite in iron-carbon alloys. It is revealed that the morphological features of excess cementite in Wootz lie in the abnormal size of excess carbides having the shape of irregular prisms. It is discovered that the faceted angular carbides are formed within the original of metastable ledeburite, so they are called “eutectic carbides”. It was found that angular eutectic carbides in the Wootz formed during long isothermal soaking at the annealing and subsequent deformation of ledeburite structures. It is revealed that carbon takes up 2.25% in Wootz (in the region of white cast iron), while none in its structure of crushed ledeburite. It is shown that the pattern of carbide heterogeneity consists entirely of angular eutectic carbides having an irregular trigonal-prismatic morphology. It is shown that Wootz (Damascus steel) is non-alloy tool steel of ledeburite class, similar with structural characteristics of die steel of ledeburite class and high-speed steel, differing from them only in the nature of excess carbide phase.

Feasibility of Solar Tracking System for PV Panel in Sunbelt Region

In the study of the feasibility of solar tracking systems for crystalline silicon photovoltaic(PV)panels in hot and cold regions,it is argued recently that a tracking system is not necessary for sunbelt countries owing to the overheating that results from excessive exposure to solar irradiance.This conclusion has been formulated based on a mathematical model,which in turn is based on the assumption that the PV module temperature can be calculated using an empirical relation of this temperature to ambient temperature,available solar irradiance,and nominal operation cell temperature(NOCT).To support this conclusion,it is claimed that the mathematical model is validated experimentally.However,this assumption is vague and widely used in the literature.The objective of the present work is to reevaluate the above-mentioned assumption and to discuss the results deriving from it.It is shown experimentally in the present work that the above-mentioned assumption overestimates the PV module temperature.At a solar irradiance of 900 W/m2,ambient temperature of 25℃,and wind speed of 5 m/s,the measured PV module temperature is lower than the value calculated based on the mentioned assumption by 29.26%.