An experimental investigation is conducted to calculate the shock Standoff (SSO) distance in front of an acute-angled wedge. For this experimentation, simple water flows channel analysis is carried out. The flow velocity is varied from 13. 2 cm/s to 25. 5 cm/s increasing in steps of 1 cm/s. A velocity of 13. 2 cm/s corresponds to Froude number 1. 13 and velocity of 25. 5 cm/s to Froude number 1. 41. The Froude number ranged from 1. 13 to 1. 41 in steps of 0. 04. The study is conducted on 5 mm thick acrylic sheets and of wedge angles 50° , 60° , and 75° to obtain a relation for calculating the SSO distance concerning the Froude number. It is found that the pressure uphill strongly depends upon the Fr and wedge angle. The SSO distance determined experimentally and using the proposed correlation are found to be in good agreement.

In this paper, the experimental study and regression analysis of the dynamic response of metal plates under impulsive loading are investigated. For this purpose, in the experimental section, 86 experiments were performed on metal plates under different conditions. The plates were made of steel, copper and aluminum in a circular shape. The effect of the measured parameters in the experimental tests such as plate thickness, loading impulse, charge mass, and Standoff distance on the circular plates deflection were evaluated simultaneously using the Design-Expert software package and response surface methodology. In this study, the material of the plates is considered as an independent qualitative parameter. In order to find a significant model, the confidence level of 95% was considered in the analysis. In this study, the value of R2 and R_adj^2 was 0.9746 and 0.9673, respectively. The results show that the predicted values of the models are in good agreement with the experimental tests and the presented models are suitable. Optimal conditions for the minimum deflection of the circular plates under impulsive loading were also presented. The impulse loading has the highest effect and the mass of the charge has the least effect on the plate deflection.

In the present research, the effect of Standoff distance on corrosion properties of the joint of three aluminum– steel explosive layers has been studied. For this purpose, the samples were welded with various Standoff distance under constant explosive load. Optical Microscopy and Scanning Electron Microscopy were used to measure the quality of the joint and type of interface. Furthermore, point analysis of EDS was used to study the local and continuous welded areas. In addition, hardness test was employed to investigate the mechanics of the joints, electrochemical polarization and impedance in order to examine the corrosion behavior of various samples. Results of the microstructural investigations have suggested wavy – vortex transition of interface and formation of locally melted areas with a combination of the joined plates as a result of Standoff distance and collision kinetic energy augmentation. Results indicated that changes of iron percentage rate in localized fusion areas of the interface had considerable effect on the cathodic behavior and corrosion caused by the galvanic cell of the interface. Moreover, the increase of collision kinetic energy in the interface led to a decrease in corrosion resistance in the impedance test.

In this paper, effect of Standoff distance parameter on morphology and mechanical properties of explosively bonded AlMg5-AI-Steel is being studied. Results have shown that by changing Standoff distance and loss of kinetic energy, the shape of interface is transited from Smooth-wavy to Wavy and wavy in a vortex way. With increasing of the Standoff distance due to the loss of kinetic energy also local melted zone has been created in front of vortices. Chemical composition of local melting zone was mixed of parent and flyer plates due to circular movement of jet. These areas have reduced bonding strength due to stress concentratio; results also have shown that strength level of all weldment was above standard level .The sample without local melting zone and wavy interface has the highest strength.

In this research, corrosion behavior of explosively bonded 304 stainless steel-Ck45 carbon steel plates was investigated. Explosive welding carried out in constant explosive ratio with 4 and 5 mm Standoff distances. The results showed that by Standoff distance increasing, the shape of interface transited to the wavy vortex type, and locally melted zones formed. Due to shock hardening, the hardness increased in near of the interfaces, and maximum hardness was related to the sample with 5 mm Standoff distance. Polarization and impedance tests results showed that maximum corrosion rate was related to the sample with maximum Standoff distance. Due to the formation of locally melted zones and increasing in impact kinetic energy in the sample with maximum Standoff distance, corrosion rate was increased.

Experimental tests were carried out to explosively clad solution annealed Inconel 718 super alloy on quench-tempered AISI H13 hot tool steel. Experimental tests were carried out using various stand-off distances and explosive ratios. Various interface geometries were obtained from these experiments. Experiments were carried out with Ammatol explosive mixture. In this study, the integrity of the bond interface was examined by the shear test. The micro hardness profiles at the interface for all samples were performed. Metallographic inspections of the bond interfaces were also carried out. The shape of interface fell roughly into two classes, wavy or wavy with some vortex shedding. In some case, a gradual change in wavelength along the direction of welding was observed which was due to a change in impact angle following plate contacts. Hardness was increased with stand-off distance and explosive ratio. Shear strength was found to be functions of interface morphology and wave amplitude.

distance-based clustering methods categorize samples by optimizing a global criterion, finding ellipsoid clusters with roughly equal sizes. In contrast, density-based clustering techniques form clusters with arbitrary shapes and sizes by optimizing a local criterion. Most of these methods have several hyper-parameters, and their performance is highly dependent on the hyper-parameter setup. Recently, a Gaussian Density distance (GDD) approach was proposed to optimize local criteria in terms of distance and density properties of samples. GDD can find clusters with different shapes and sizes without any free parameters. However, it may fail to discover the appropriate clusters due to the interfering of clustered samples in estimating the density and distance properties of remaining unclustered samples. Here, we introduce Adaptive GDD (AGDD), which eliminates the inappropriate effect of clustered samples by adaptively updating the parameters during clustering. It is stable and can identify clusters with various shapes, sizes, and densities without adding extra parameters. The distance metrics calculating the dissimilarity between samples can affect the clustering performance. The effect of different distance measurements is also analyzed on the method. The experimental results conducted on several well-known datasets show the effectiveness of the proposed AGDD method compared to the other well-known clustering methods.

In this study, the microstructure of the joint interface in three-layer explosive welding of austenitic stainless steel 321 - aluminum 1050 - aluminum 5083 was examined before and after heat treatment. The welded samples were subjected to heat treatment at temperatures of 250°C and 350°C for durations of 1000, 3000, and 10000 seconds. Microstructural analysis was performed using optical microscopy and scanning electron microscopy. The results revealed that under all conditions, the Joint Interface of aluminum 5083 - aluminum 1050 exhibited a flat and defect-free structure. With increasing Standoff distance, the Joint Interface of stainless steel 321 - aluminum 1050 transitioned from a smooth to a wavy pattern, and the average layer thickness increased from 4.95 μm to 6.7 μm. During heat treatment, the layer thickness in the Joint Interface increased proportionally to the diffusion kinetics, reaching maximum values of 18.56 μm and 15.02 μm for samples with Standoff distances of 6.75 mm and 6 mm, respectively. The activation energies for diffusion were calculated as 46.6 kJ/mol and 42.4 kJ/mol, and the diffusion constants were 142.2 ms-1  and 45.3 ms-1 for the same samples.

Background & Aim: There are several methods for determination of occlusal vertical dimension. The vertical dimension of rest position, interocclusal distance and closest speaking space are two important methods. The purpose of this study was comparison the variability of interocclusal distance and closest speaking space in denture wearers.Method &Materials: The subjects were 34 edentulous patients (18 males & 16 females with mean age of 56) who had received complete dentures in the prosthodontics department of Isfahan dental school. They had good residual ridges. The dentures had correct clinical vertical dimension with 1-2mm overjet and 0.5 -1mm overbite. There was no evidence of neuromuscular and TMJ problems. The TOM guage was used for measuring the vertical dimension of rest position and «S» position.Results: The results showed that the mean and standard deviation of interocclusal distance were smaller than closest speaking space. Paired T-test and Levene's test were used for statistical analysis. There was a statistically difference between interocclusal distance and closest speaking space, so the interocclusal distance was less variable than closest speaking space (P<0.05).Conclusion: The closest speaking space during S position is affected by the occlusion, vertical and horizontal overlap of anterior teeth. These factors are up to dentist's judgement in complete denture and can influence the variability of vertical dimension of S position. Because of this variability it is recommended to use several methods for determining of vertical dimension.