Papers by Keyword: Penetration

Abstract: Tungsten Inert Gas Welding (TIG) is a welding process that has low weld penetration and low heat intensity of the electric arc. This affects the low productivity of processes. To overcome this drawback, Activated Tungsten Inert Gas Welding has been developed. This study investigates Al-7 series plates using the A-TIG welding process. Different kinds of fluxes, TiO2 and Al2O3 are used with a ratio of 1:1 mixture of both these powders. This mixture was applied on Al-7075 plates to enhance weld characteristics. Activated flux has been used to improve the weld depth. The effects of various process parameters (welding current (I), welding speed(V), and gas flow rate were analysed and compared with the TIG welding method. Activated Tungsten Inert Gas (A-TIG) welding canincrease the joint penetration and weld depth width ratio compared to conventional TIG welding. The main objective of this work is to enhance weld penetration, improve mechanical properties (tensile strength and elongation), and assess metallurgical changes in Al-7075 joints using A-TIG welding with TiO₂ and Al₂O₃ mixed fluxes.

Abstract: Calcium hydroxide (Ca (OH)₂) is an intracanal medicament used as a disinfectant in cases of tooth inflammation with ad dubia prognosis. The success of root canal treatment depends on the ability of intracanal medicaments to eliminate pathogenic bacteria present in the walls of narrow and complex root canals by releasing calcium and hydroxyl ions at the closest contacts. This study aimed to evaluate the effect of particle size on the ability to penetrate Ca (OH)₂ in the coronal, middle, and apical root canals. Fifteen mandibular premolars extracted for orthodontic and periodontal purposes were collected and cut to produce root canals with a length of 12 cm. The root canals were then prepared with a Protaper SX-F3 needle and irrigated using a solution of 2.5% NaOCl, NaCl, and 17% EDTA as lubrication at each needle change. Ca (OH)₂ with different particle sizes in paste form was manipulated with distilled water at a concentration of 0.8 g/mL then the paste was applied to the prepared tooth root canals and covered with a temporary filling. The samples were then stored in an incubator at 37 °C for 7 days. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX) was performed on the transverse surfaces of the coronal 1/3, middle 1/3 and apical 1/3 of the tooth. The maximum penetration depth was evaluated by measuring the maximum distance between the dentin canal wall and Ca (OH)₂ present in the dentinal tubules. In all three zones, the Ca (OH)₂ nanoparticles had a greater penetration depth than the Ca (OH)₂ nanoparticles (P<0.001). In both groups, the penetration depth increased from the apical to the coronal section. All differences in the penetration test ability of the Ca (OH)₂ nanoparticles and Ca (OH)₂ microparticles at all depths of the surface. Ca (OH)₂ nanoparticles penetrate deeper into the dentinal tubules than Ca (OH)₂ microparticles do.

Abstract: Stainless steel is widely employed in a variety of industries, including aerospace, chemical processing, and transportation. It can be recycled indefinitely with no loss of property. The Gas Tungsten Arc Welding (GTAW) or Tungsten Inert Gas (TIG) technique is widely used for connecting thin pieces of stainless-steel. However, it is ineffective for combining heavy parts in a single pass. Activated TIG (A-TIG) dramatically enhances weld penetration up to 1.5- 4 times in a single pass. A-TIG is the centre of investigation among researchers because of its deep penetrating capacity. This article discusses the effects of particular flux powders, such as NaF and Fe₂O₃, on surface appearance and geometric shape. Weld of satisfactory appearance is produced using NaF powder as a flux in TIG welding, whereas, Fe₂O₃ powder results in a substantial increase in both the joint-penetration and weld-aspect ratio.

Abstract: Advance nanoscale patterning technology requires high resolution lithography, from ultraviolet (UV, i-line system) to deep ultraviolet (DUV, KrF system) until extreme ultraviolet (EUV), but the compatibility study of new resist types and wet etchant is lacking. The compatibility is defined as the duration of a photoresist being able to withstand in wet oxide etchant. Poor compatibility has potential resist lifting and/or penetration during wet etch process, which causes electronic device performance drifting. Currently, wet oxide etching is widely used in the gate oxide wet etch using patterned resist, as well as in the backside oxide removal with blanket resist front-side coverage. In this paper, we explore the compatibility and understand the impact factors, based on commonly used resist (i.e., KrF and i-line system resist) and wet etch chemicals (i.e. HF based etchant) in industry. It is important to do a quick and straightforward compatibility check before we implement new resists on actual product wafers, to prevent poor compatibility caused resist lifting and/or penetration during wet etch process. Based on oxide thickness check and resist lifting phenomena, it is found that resist baking condition, resist polymer type, resist composition, and lag time from resist coating to wet oxide etching all will affect the compatibility between HF based etchant and resist.

Abstract: In many structural applications, such as marine, aircraft and so on, structures are designed to withstand high impact loading, because they may be subjected to impact of the projectiles with high velocity [1,2] . Fabrics become good choice to resist impact of ballistic [3] because of light weight and high specific strength .

Abstract: This work presents the results of optimization compositions of polymer-modified binder (PMB) by a compromise task. The conducted study of influence two prescription factors – containing styrene-butadiene-styrene and sulfur – on which is a set of indicators of polymer-bitumen binders were carried out. The regularities of these factors of mutual influence were established by such indicators as the Fraas brittleness temperature, penetration, softening point, ductility. The dosages of SBS and sulfur have been determined by ensuring the achievement of the required level of PBB indicators in accordance with GOST R 52056-2003 «Bitumen-polymer road binders are based on styrene-butadiene-styrene block copolymers. Specifications».

Abstract: The penetration damaging behavior of ATI425 titanium alloy was studied by 7.62 mm diameter armor piercing projectiles. The damage characteristics and the mechanism were analyzed by observing and analyzing the craters of ATI425 titanium alloy target. It can be found that local temperature-rise of the target plate occurred, even sputtering phenomenon in the opening stage. The shear bands extended upward along the cater wall could be seen in the stable stage. The large non-homogeneous deformation in adiabatic shear bands caused microcracks and micropores. A large number of macro-cracks were observed on the side wall and at the bottom of the crater.

Abstract: The use of natural rubber-like crepe rubber as an asphalt additive is very susceptible to aging. Aging on asphalt crepe rubber can occur during the mixing process or its use for the road. Studies on the prevention of aging on asphalt are still being developed to produce asphalt resistance to aging and have good performance in preventing deformation. Some studies that have been done are the addition of other additives such as antioxidants. This study aims to study the effect of adding crepe rubber and the antioxidant 1,2-dihydro-2,2,4-trimethyl-quinoline (TMQ) to the Marshall characteristics of rubber asphalt. Preparation of the rubber asphalt sample begins with making crepe rubber, which is by milling raw natural rubber in the form of a cup lump using a creeper. The crepe rubber product contains dry rubber content of more than 95%. Then the crepe rubber masticated using an open mill to soften and form it with 2 mm thickness. Then the crepe rubber is melted at 200 °C before being mixed with asphalt, heated to 165 °C. The crepe rubber content in the asphalt mixture is made 10%, and during the mixing process, the TMQ was added with contents of 0%, 1%, 2%, 3% w/w. The rubber asphalt samples were then tested for their penetration and marshall characteristics, using ASTM D5 and ASTM D6927 standards. The test results show that the addition of the TMQ can improve the penetration properties and stability of the rubber asphalt in holding the load. However, the addition of the TMQ of more than 2% causes a decrease in the rubber asphalt's stability properties. The best results were obtained by adding 2% TMQ with 68.7 dmm penetration and optimum asphalt content of 5.50%. Results of the marshall test for the sample are marshall stability 1403.96 kg, void filled aggregate (VFA) 75.90%, void in a mixture (VIM) 3.07%, void mineral aggregate (VMA) 15.34%, flow 3.370 mm, and marshall quotient (MQ) 420.8 kg/mm.

Abstract: The panel attached in bulletproof vests must fulfill the standard of NIJ 0101.06. It must resist the penetration of the bullet and has a back-face signature that does not exceed 44 mm by ballistic testing. This research included both numerical simulation and ballistic tests for validation using type IV ballistic bullet. This research involved composite epoxy-HGM-hemp (Boehmeria Nivea) and epoxy-HGM-sisal (Agave Sisalana) as bulletproof panel materials with their woven-thickness characteristic. The properties of materials are obtained by performing ASTM D3039 test. As a result, by varying the thickness or each amount of layer, the thinnest panel of each material that fulfills the standard of NIJ 0101.06 is obtained.

Abstract: In order to study the penetration performance of the tandem warhead composed of a front circular shaped charge and a rear penetration projectile, a grooved steel plate was processed to simulate the effect of circular shaped jets on metal plate, then the failure mechanism of the grooved steel plate impacted by rear projectile was investigated by ballistic experiment, meanwhile, the effect of projectile nose shape on the failure mechanism was also analyzed. The results show that the main failure mechanism of grooved steel plate is ductile tensile deformation or damage when the projectile impacted on the inner plate body and the depth of the pre-splitting groove is not big enough (usually more than 4mm), on the other hand, the circumferential sheared fracture of the bottom of the groove occurred when the depth of the pre-splitting groove is not less than 4mm. The oval projectile body has much greater erosion damage than rod-shaped projectile during the penetration process.