NOVEL SIDE-VENT-CHANNEL BASED BLAST MITIGATION CONCEPT FOR LIGHT TACTICAL VEHICLES

A new concept solution for improving survivability of the light tactical military vehicles to blast-loads resulting from a shallow-buried mine detonated underneath such vehicles is proposed and critically assessed using computational engineering methods and tools. The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called \u27pulse detonation\u27 rocket engines, in particular, and is an extension of the recently introduced so-called \u27blast chimney\u27 concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle). Relative to the blast-chimney concept, the new solution offers benefits since it does not compromise the cabin space or the ability of the vehicle occupants to scout the environment and, is not expected to, degrade the vehicle\u27s off-road structural durability/reliability. The proposed concept utilizes properly sized and shaped side-vent channels attached to the V-shaped vehicle underbody. The utility and the blast-mitigation capacity of this concept is examined in the present work using different (i.e. coupled Eulerian/Lagrangian and coupled finite-element/discrete-particle) computational methods and tools. To maximize the blast-mitigation potential of the proposed solution, standard engineering optimization methods and tools are employed for the design of side-vent-channels. It is shown that, by proper shaping and sizing of the side-vent-channels, venting of ejected soil and supersonically-expanding gaseous detonation products can be promoted, resulting in an increase in the downward thrust on the targeted vehicle. Furthermore, it is found that optimization of the geometry and size of the side-vent-channel solution for the maximum blast-mitigation performance, requires consideration of a tradeoff between the maximum reductions in the detonation-induced total momentum transferred to, and the acceleration acquired by, the target vehicle. The results obtained farther confirmed theblast-mitigation effects of the side-vent-channels, although the extent of these effects is relatively small (3-4%)

Evaluation of Early Active Controlled Motion in Flexor Tendon Repair

Objectives: The objective was to determine the results of early active controlled motion in the patients rehabilitated by our new protocol. Methods: 91 fingers in 64 patients with flexor tendon repair in all zones were enrolled in a single group (quasi-experimental) clinical trial. 58 fingers in 43 patients were assessed at least three months postoperatively. Outcomes were defined using the 'White' criteria for thumbs and the 'Strickland' criteria for other fingers. Results: The results for range of motion of fingers were Excellent in 70.7%, good in 13.8%, fair in 6.9% and poor in 8.6%. There were 3 (5.17%) postoperative tendon ruptures. Discussion: Early active controlled motion with our rehabilitation protocol shows acceptable postoperative results. This rehabilitation protocol is more effective if carried out from the 1st to 4th weeks after surgery, under the supervision of a surgeon or hand therapist. Then, from the 4th to 6th weeks, it should be performed at a hand therapy clinic and from the 6th to 12th weeks at home, supervised by a hand therapist

Cathodic synthesis of Al-Ce-Mn Oxide nanohybride powder with improved surface for effective removal of fluoride from aqueous media

Al-Ce-Mn oxide samples were synthesized by the cathodic electrochemical method at current densities of 5, 15, and 35 mAcm-2. The XRD, SEM, and EDX techniques were used for the characterization of samples. The SEM images show that at high current density the one-dimensional(nanowire) structure and at low current density two-dimensional (nanosheet) structure were obtained. Moreover, the particle sizes are decreased with increasing the current density. The samples were applied for the uptake of fluorine (F-) ions from solutions. The influence of the contact time, initial fluoride concentration, and solution pH on the adsorption was investigated. The results showed more than 80 % of F-  ions were uptake from solution during the three hours initial contact times and the uptake capacity has little change at pH below 6 and it has a sharp decline with increasing solution pH. The kinetic data were well fitted to the pseudo-second-order model and the equilibrium adsorption data was well described by the Langmuir isotherm model.  The adsorption capacity was 48 mg/g at pH 6 and room temperature

Credit Card Fraud Detection Using Asexual Reproduction Optimization

As the number of credit card users has increased, detecting fraud in this domain has become a vital issue. Previous literature has applied various supervised and unsupervised machine learning methods to find an effective fraud detection system. However, some of these methods require an enormous amount of time to achieve reasonable accuracy. In this paper, an Asexual Reproduction Optimization (ARO) approach was employed, which is a supervised method to detect credit card fraud. ARO refers to a kind of production in which one parent produces some offspring. By applying this method and sampling just from the majority class, the effectiveness of the classification is increased. A comparison to Artificial Immune Systems (AIS), which is one of the best methods implemented on current datasets, has shown that the proposed method is able to remarkably reduce the required training time and at the same time increase the recall that is important in fraud detection problems. The obtained results show that ARO achieves the best cost in a short time, and consequently, it can be considered a real-time fraud detection system

Immobilized nickel hexacyanoferrate nano particles on graphen for effective removal of Cs(I) ions from radionuclide wastes

In the current work synthesis and modification of graphene oxide with Nickel Hexa Ferrocyanide (NiHCF) nanoparticles has been reported. The Graphene oxide- Nickel Hexa Ferrocyanide (GO-NiHCF) was used as an adsorbent to remove Cesium (Cs) ions from a simulated solution. The obtained product was characterized with XRD, SEM, TGA, FTIR, and BET techniques. The SEM images and XRD pattern confirms the successful immobilization of Nickel Hexa Ferrocyanide on graphene oxide sheet. The cesium removal ability of GO-NiHCF was evaluated in batch mode. Effect of various parameters such as pH, initial concentration, contact time, and interferences ions were studied. The results cleared that the maximum adsorption for Cs removal was 240 mg g-1. Equilibrium modeling studies suggest that the data are reasonably and relatively fitted well to the Langmuir adsorption isotherm. Kinetic studies show that sorption process is fairly rapid and the kinetic data are fitted well to the pseudo-second order rate model. This composite offers strong potential in the field of elimination of Cs that requires rapid and complete decontamination

New metal organic framework (MOF) nanoparticle for gas separation by matrix membranes

{[Dy(BTC)(H2O)]•DMF}n metal organic framework nanoparticles was synthezed through solvthermal method. The product was characterized by XRD, TG, BET, and SEM techniques. SEM images showed that the synthesized sample has semi-cubic particles with average size of 70 nm in length.For improve the gas separation performance,the MOF nano particles were dispersed in polydimethylsiloxane (PDMS) for preparation of mixed matrix membrane (MMM) on support of polyethersulphone (PES). The performance of obtained MMM in separation of NO, N2 and O2 gas were investigated, and the effect of MOF nanoparticles (5, 10, and 15% wt)and feed pressure (100-250 kPa) on permeability and selectivity were studied. It was found that the membrane performance is evaluated by addition of MOF nano particles in membrane (polymeric matrix), and the feed pressure have not important effect on separation. The performance (NO/N2 and NO/O2 selectivity) increased as the loading of MOF particles (up to 15% wt) being dispersed within the polymer matrices

Densification and Devitrification of Fused Silica Induced by Ballistic Impact: A Computational Investigation

A molecular-level computational investigation is carried out to determine the dynamic response and material topology changes of fused silica subjected to ballistic impact by a hard projectile. The analysis was focused on the investigation of specific aspects of the dynamic response and of the topological changes such as the deformation of highly sheared and densified regions, and the conversion of amorphous fused silica to SiO2 crystalline polymorphs (in particular, α-quartz and stishovite). The topological changes in question were determined by carrying out a postprocessing atom-coordination procedure. This procedure suggested the formation of stishovite (and perhaps α-quartz) within fused silica during ballistic impact. To rationalize the findings obtained, the all-atom molecular-level computational analysis is complemented by a series of quantum-mechanics density functional theory (DFT) computations. The latter computations enable determination of the relative potential energies of the fused silica, α-quartz and stishovite, under ambient pressure (i.e., under their natural densities) as well as under imposed (as high as 50 GPa) pressures (i.e., under higher densities) and shear strains. In addition, the transition states associated with various fused-silica devitrification processes were identified. The results obtained are found to be in good agreement with their respective experimental counterparts

Comparison of Sole to Palm Reconstruction Using the Combined Medial Plantar and Medial Pedis Free Flaps and Abdominal Pedicle Flap for Extensive Palm Injuries

"nThe coverage of soft- tissue defects of the hand specially volar side needs special consideration. Although certain local flaps have been described and used for resurfacing the palm, Extensive injury requires distant or free flaps for coverage. abdominal pedicle flap has been traditionally used for extensive hand injuries, however there is no doubt that one of the ideal tissues for resurfacing the volar of hand is plantar tissue. We reconstructed the hand with a new procedure of combined medial plantar and medial pedis free flap , and compared it with 15 cases, whom their extensive palm injuries reconstructed with abdominal pedicle flap. The result was significantely better in respect to sensation, Texture of the Hand and patient satisfaction in compare of Abdominal flap