---

The increasing production and use of fossil fuels increase the probability of soil source contamination by oil and petroleum products, and pose a hazard to life. There are over 43,000 chemical contaminated sites in Canada and USA, with 2,200 of them classified as high risk. In the US, over $10 billion are spent annually on the cleanup of contaminated sites. The primary objective of this study was to develop and test an innovative in situ soil washing system that could extract contaminants from the soil, quickly and effectively, without causing any threat to water sources. We proposed the use of an organic solvent in our system that is not only lighter than water but is also immiscible with water. It was in-troduced into the soil profile from below using a system of horizontal, underground per-forated pipes, and collected from the soil surface. Since the solvent was being introduced from the bottom, it “wete” the soil completely and thus removed the contaminant effec-tively. To understand and evaluate the performance of the system for remediation, a pre-liminary experiment was performed using two stainless steel columns (1m long x 0.2m di-ameter) packed with two diesel fuel contaminated soils (fresh and old contamination). The proposed technique is innovative, unique and very fast for the remediation of diesel fuel contaminated soils. It is the first study of its kind employing a subirrigation system for de-livering organic solvents (lighter than water and immiscible in water) for in situ soil wash-ing. Some preliminary applications of the system to diesel fuel contaminated sand soils have proved very promising for both fresh and old contaminated sites. The method could be equally suited for other contaminants also.

---

A honeycomb panel consists of an array of open hexagonal cells which their walls are perpendicular to face sheets although other panel sandwiches don’t have these perpendicular walls. Their design is often performed based on minimum weight. This research is aimed at minimizations of weight by means of computing honeycomb core girth. Weight optimization is done by means of Naive and numerical procedures. Numerical optimization is done by the sequential quadratic programming (SQP) method. Geometric parameters and optimized weight are calculated for hexagonal and square cells. Optimized weights for these two cross-sections are compared. Keywords: Honeycomb Weight Optimization, Sandwich Panels, Numerical optimization, Sequential Quadratic Programming.

---

To evaluate the yield and quality of barley (Hordeum vulgare)–vetch (Vicia desycarpa) intercropping, a series of experiments were conducted at the Experimental Field of the College of Agriculture, University of Tehran, in Karaj (Iran) from 2003 to 2005. The ex-periments were arranged in a randomized complete block with a split plot design and four replications. Three levels (0, 45 and 90 Kg N ha-1) of nitrogen fertilizer and three cropping systems (sole barley, sole vetch and barley-vetch intercropping) were allocated to the main and sub plots, respectively. The barley-vetch intercropping treatment had a replacement arrangement (50: 50) with single alternate rows. Land equivalent ratio (LER), was used to compare sole cropping with intercropping systems. Results showed the supremacy of intercropping of barley and vetch over single crops. Generally, increas-ing nitrogen fertilizer caused a decreasing trend in the biological efficiency of intercrop-ping. The highest LER for grain was obtained in control (N fertilizer free) plots (LER= 1.145). Nitrogen fertilizer increased the forage yield, grain yield, crude protein content, and crude protein yield of barley and vetch in sole and intercrops. Nitrogen application increased water use efficiency. In this study, barley was the dominant crop. The inter-cropping vetch and barley had the highest productivity and crude protein yield.

---

The most important application of explosive welding in cylindrical geometry is cladding of cylindrical surfaces in order to increase corrosion and wear resistance and also improving the mechanical properties of bimetal product. In this study, the explosive welding of bimetal tubes made of steel and Phosphor-Bronze was investigated using two explosives (TNT and Amatol 5-95) with different explosion velocity. At first the explosive window of two metals was achieved using the theoretical-experimental relations, and then using different experiments, the key role of explosion velocity and also the position of selected parameters of explosive window in the metals weldability were determined. At the end, the successfull method of manufacturing of this bimetal tubes is presented and commented upon.

---

- In this paper an analytical model for prediction of angular deformation is presented. In this model convective heat losses and a multipoint distributed heat source is used for determination of the inherent strain zone which causes the bending angle. The effects of laser bending process parameters including laser power, beam diameter, scan velocity and pulse duration on the bending angle were investigated experimentally. Main effects of factors were considered and the regression line was derived. An L9 Taguchi’s standard orthogonal array was employed as experimental design and the level of importance of the laser bending process parameters on the bending angle was determined using analysis of variance (ANOVA). Comparison of the analytical model and experimental results has shown a reasonable agreement.

---

In this paper, a theoretical formula is derived to predict the instantaneous folding force of a single-cell square column under axial loading. Calculation is based on analys of “Basic Folding Mechanism” introduced by Wierzbicki and Abramowicz to calculate the instantaneous folding force. For this purpose, three mechanisms of energy dissipation were assumed. The formula obtained in this paper, can predicts the instantaneous folding force variations versus folding distance and versus folding angle with good precision and can predict folding force in each time instance instead of the average value. The results of theoretical formula were compared with experimental data and good agreement was observed. Keywords: Instantaneous Force, Folding, Honeycomb, Square Column.

---

An accurate determination of evapotranspiration is required for many studies that involve estimation of the water balance. One methodology is the use of lysimeters. Considering the semiarid climate of Kerman Province, in southeastern parts of Iran, the only operating electronic weighing lysimeter in the country was used for calculating daily ETo from April 2004 to March 2005 in three different periods, i.e. the entire year, and high and low evaporative demands periods. The measured error was equal to 1 kg mass, which is equivalent to 0.14 mm of water in the field. An automated weather station was used that provided 10-min recordings of the weather data to be used for predicting daily ETo with models. The lysimeter was installed in proximity of the automated weather station and both were located in a field with grass cover. The lysimeteric data were used for the evaluation of six grass evapotranspiration models, including FAO-56 Penman–Monteith, Penman-Kimberly 1996, FAO-24 Blaney-Criddle, FAO-24 Radiation, Makkink, and Hargreaves-Samani. The root mean square error (RMSE) and index of agreement (d) were used for assessing prediction accuracy of different models. Results indicated that for the entire year period, the FAO-24 Radiation equation was the most precise method for calculating ETo, with a RMSE of 1.63 mm day-1 and a d- index of 0.78. During the high evaporative demand period (April to September 2004) the FAO-24 radiation equation was superior compared to the other methods for calculating ETo with a low RMSE value of 1.86 mm day-1 and a d-index of 0.45. During the low evaporative demand period, again, FAO-24 radiation equation was superior compared to the other methods with RMSE of 1.30 mm day-1 and d-index of 0.46. In all of the three periods, the Makkink method showed poor performance and can not be recommended for the region.

---

Seasonal variations of climatic parameters are significant in arid and semi-arid regions and sensitivity of each parameter may differ in different seasons. No work has been done in this regard in Iran. Therefore, in this study, sensitivity analysis of the ASCE-Penman-Monteith grass reference evapotranspiration (ETo) equation was investigated on the basis of variation of mean air temperature (Tmean), vapor pressure deficit (VPD), wind speed at 2 meter height (U2), and short wave solar radiation (Rs) in the semi-arid climate of Kerman, southeast of Iran. The sensitivity coefficients were derived for each variable on a daily basis. The results showed that the computed ETo was sensitive to VPD in all months, to U2 during March to November, and to Rs during the summer months. The change in ETo was linearly related to the change in the climatic variables, with in most cases. The sensitivity coefficient for Rs was higher during the summer months and lower during the winter months. Increase in ETo with respect to the increase in the aforementioned climate variable changed by month. On an annual average, 1 C increase in Tmean, 1 ms-1 increase in U2, and one MJ m-2d-1 increase in Rs resulted in, respectively, 0.11, 0.37, and 0.09 mm d-1increases in ETo. A 0.4 kPa increase in VPD resulted in 0.85 mm d-1 increase in ETo. Generally, various meteorological parameters should be measured with high accuracy in order to use the combination model.

---

In this study, factors affecting ballistic performance of fabrics used, including material properties, projectile geometry, boundary conditions, fabric dimensions, multiple plies of fabric armors and friction, has been studied. Ballistic limit was obtained as a criterion of ballistic performance of fabric to identify and compare the effect of the mentioned factor. To obtain the ballistic limit, ballistic tests were performed on the fabric. Also, a finite element model was created using LS-DYNA software and the results of the the simulation of this model show an acceptable agreement between the experimental and numerical analysis. Due to limitation in experimental tests,many of factors affecting performance of armors can be evaluated using this model.

---

In this paper, the experimental behavior of grid cylindrical composite structures which are used widely in engineering structures under ballistic impact is investigated. In the present study, the grid cylindrical composites were manufactured by the filament winding process with fiber placement procedure and perforated by projectile using the ballistic gas gun. Input and output velocities of projectile were recorded. The results show that presence of discrete ribs prevents spread damage from one cell to it’s adjacent cells and structure behaves differently against projectile with velocity near ballistic limit velocity and higher velocities. With approach to the ribs location ballistic limit has been increased. However due to reduce fracture area, overall and local deformations after impact in velocity which is higher than ballistic limit velocity, projectile has been came out from grid samples with higher velocity than simple composite shells. In this paper, delamination in outer composite shell and ribs, debonding between shell and ribs, residual velocity of projectile, fracture area of the grid specimens and the effects of curvature in two deferent velocities were reported and commented upon as results.

---

Forming limit diagram (FLD) shows the formability of metal sheets under different loading conditions before that necking is taken place. In this paper, the application of plastic instability criterion for prediction of necking and also FLD has been investigated. Using Balart’s anisotropic yield function and plastic instability criterion in different strain ratios, limit strains have been calculated, and then the limit strains have been converted to limit stresses. To verify the analytical results, a free bulge setup with the ability of applying the axial feeding has been fabricated. Tubes have been undergone different loading paths and different plane strain conditions have been induced to obtain FLD. FLDs which have been obtained using plastic instability criterion have been compared with experimental results. The results show that swift instability criterion for tubes have the best prediction of FLD in tube hydroforming process.

---

In this paper, ballistic impact on sandwich panel with composite face sheet made of Glass/Epoxy and aluminum honeycomb core has been studied. The solution is derived from a wave propagation model. At first both analytical and numerical solutions were clarified and their results were compared with experimental results. Some deformation patterns, failure modes and energy absorption mechanisms were identified by observation, such as: dynamic movement of the target, stretching, bending deformation, delamination, debonding, shear fracture honeycomb, tensile fracture of Glass/Epoxy and plug and petal formation in composite facings. The solution involves a four-stage and effective masses of the face sheets and core as the shock waves travel through sandwich panel are derived using Lagrangian mechanics. The resulting non-linear differential equation of motion was solved considering the local damage effects and corresponding energy absorptions. Also numerical model, analysis of the penetration process was performed by a nonlinear explicit finite element code, LSDYNA. The results of analytical solution and numerical simulation are compared with experimental tests. Ballistic impact tests is carried out on the samples by flat-ended projectile with 8/5 gr mass and 10 mm diameter in difference velocities.

---

Axial compression behavior of foam materials can be explained by two ideal deformation scenarios: discrete crush band process and progressive collapse. In this paper, a perfectly new model for strength assessment and quantitative/qualitative description of one-dimensional progressive collapse of aluminum foams under impulsive loadings is presented and its capability to split this way of crushing into two distinct regimes of shock wave and elastic- plasic wave propagation is highlighted. Then, using conservation relations and the new introduced model, the analytical solution of dynamic deformation of aluminum foams in the two mentioned regimes is developed. Regime 2 considers the case when the crushing front velocity is lower than the linear sound velocity of the foam; but remains higher than the effective sound velocity for a perturbation in which the amplitude lies in the so-called “plateau region’ of the static stress-strain diagram. The physical difference between this regime and the fiest one entails not only the creation a shock front associated with the collapsing foam, but also an acoustic precursor in the case of second regime.Finite element simulation is also performed to validate the analytical procedure. The numerical prediction is found to be in very good agreement with the analytical results.

---

In this article, an improved 3D finite element (FE) model of low velocity transverse impact on armchair and zigzag single-walled carbon nanotubes (SWNTs) has been developed. Numerical examples for estimating the Young’s modulus of nanotubes are presented based on explicit and implicit analysis to illustrate the accuracy of this simulation technique. Based on explicit finite element model, the maximum dynamic deflections of single-walled carbon nanotubes with different boundary conditions, geometries as well as chiralities are obtained and then compared with theory investigation. Impact of a mass on simply supported and clamped nanobeams are investigated by using nonlocal Euler–Bernoulli and Timoshenko beam theory. The simulation results demonstrated good agreement with analytical results based on Euler–Bernoulli and Timoshenko nonlocal theory. When the aspect ratio is increased, the maximum dynamic deflection at the center of the beam is increased for both of the simply supported and the clamped-clamped nanobeams. The inclusion of the nonlocal effect increases the magnitudes of dynamic deflections. The dynamic deflections predicted by the classical theory are always smaller than those predicted by the nonlocal theory due to the nonlocal effects.

---

In this study, experimental tests were performed to evaluate the effects of axisymmetric cylindrical projectile nose shapes and initial velocities on ballistic performance of laminated woven glass epoxy composites. Projectile initial velocity and nose sharpness changes, absorbed energy, delamination area, etc. are investigated by six blunt, hemispherical, conical and ogival projectiles. Hand lay-up method has been used to manufacture composite targets with 18 layers of 2D woven glass fibers of 45% fiber volume fraction. The epoxy system is made of epon 828 resin with jeffamine D400 as the curing agent. The results show that the maximum influence of projectile geometry on target behavior, occurs in ballistic limit area. In this range of initial velocity, ogival (CRH=2.5) and Blunt projectiles show the best and the worst ballistic performance. The delamination area decreases as the projectile nose sharpness increases or its initial velocity decreases. Ballistic curves for different projectiles show that the difference between projectiles behavior decreases in higher impact velocities. Because of target shear failure in blunt projectile impact, the amount of target absorbed energy for this projectile is less than other projectiles in higher impact velocities away from ballistic limit velocity.

---

In this paper, the tensile properties of 2D woven glass epoxy composite reinforced by two different nanoparticles have been investigated and compared. Hand lay-up method has been used to manufacture nanocomposites with 12 layers of 2D woven glass fibers with 40% fiber volume fraction. The nano-epoxy resin system is made of epon 828 resin with jeffamine D400 as the curing agent. The composites were reinforced by adding organically modified montmorillonite nanoclay (Closite 30B) and nanosilica (SiO2) particles. The nanoclay particles were dispersed into the epoxy system in a 0%, 3%, 5%, 7% and 10% ratio in weight with respect to the matrix, while the spherical nanosilica particles were dispersed into the epoxy system in a 0%, 0.5%, 1% and 3% ratio in weight with respect to the matrix. The results show that low loading of nanoclay decreases the mechanical properties of nanocomposite, while significant improvements of nanocomposite mechanical properties are shown in low loading of nanosilica. Tensile strength and toughness of nanocomposite increase by 7% and 10% after adding 5 wt.% nanoclay. Loading of 0.5 wt.% nanosilica cause 10% and 27% improvement in tensile strength and toughness of nanocomposite.

---

In this study, the numerical and experimental study of energy absorption and deformation of thinwalled tubes with square geometry and circular cross under impact loading is studied. The purpose of this study was to investigate the effect of geometry on the energy absorption of aluminum tubes and the effect of foam filled tubes to absorb more energy under transverse impact. In the experimental part, the tubes of aluminum in form of hollow and filled with solid polyurethane foam prepared and then the quasi-static tests with static and dynamic loading rates by drop hammer have been performed on samples with different energy and the acceleration-time diagrams in each test is obtained. In the last part of this study simulation of the phenomenon of transverse impact on thin sections was carried out with the ABAQUS software. The discussion and conclusions of this study, the results of experimental tests carried out by the author of the thesis has been compared with the results of numerical analysis show a good agreement(difference below twenty percent). Finally, it was concluded that with regard to material of structure, at high energies square tubes have 50 percent specific energy absorbed higher than circular tubes and filled tubes have 20 percent specific energy absorbed higher than hollowone's. And transverse displacement of the hollow tube and circular tube is always higher than the filled tube and square tube.

---

This paper, experimentally evaluates the effects of indenter geometry on quasi-static perforation process of laminated woven glass epoxy composites. Low loading rate tests were performed, using six indenters with blunt, hemispherical, conical (cone angle of 37˚ and 90˚) and ogival (caliber radius head of 1.5 and 2.5) nose shapes. Composite behaviors like energy absorption, contact force, failure mechanisms and friction force were investigated for different indenter shapes. Hand lay-up method has been used to manufacture composite targets with 18 layers of 2D woven glass fibers of 45% fiber volume fraction. The epoxy system is made of epon 828 resin with jeffamine D400 as the curing agent. The results show that the load displacement curve is divided to five areas. Some of these areas may have higher or lower magnitude, depending on indenter nose shape. The highest contact force is exhibited by unsharpened indenter. The lowest contact force and so the best performance is seen in ogival (CRH=2.5) indenter. Comparing absorbed energies shows that for an identical dent depth, the amount of absorbed energy is major for unsharpened indenters. The 37˚ conical indenter needs the highest energy for perforation, which is 2.6 times more than blunt indenter’s.

---

Due to high hardness, low density and heat resistance, ceramics are widely used in armor applications and industry, thus, in this study, perforation process of projectile into ceramic targets is investigated analytically and numerically and a modified model is developed. In the analytical section, Woodward’s theory, one of the important theories in perforation process of projectile into ceramic targets, is investigated and some modifications are applied in Woodward’s model, hence the ballistic results of analytical method are improved and the modified model shows good agreement with the experimental results that in the analytical section, the modified model is based on Woodward’s model and modification of semi-angle of ceramic fracture cone, erosion, mushrooming and rigid from of projectile and also changes in yield strength of ceramic during perforation process, damage, are considered. In the numerical section, a finite element model is created using Ls-Dyna software and perforation process of projectile into Ceramic-Aluminum target is simulated. The results of the analytical method and numerical simulation are compared to the results of the other investigators and results of modified model show improvement in prediction of ballistic results.

---

The low velocity impact behavior of steel panel with different curvature is investigated experimentally. Numerical analysis is used for test results verification. In experimental method drop impact test apparatus is used so three different height for falling weight is considered. Also three different panel curvatures for experiment are used. Two important parameters measured are maximum acceleration and maximum plastic deformation of panel. A high speed accelerometer is used for measuring the impactor acceleration. Also the permanent plastic deformation is measured with numerical measurement system attached to the drop test apparatus.Experimental analysis with three different radius of curvature is modeled with numerical analysis, the numerical analysis is used for further panel curvatures so the panel behavior is estimated in a wide range of panel curvatures. The results in numerical analysis and test (if available) show good agreement when compared together. the results show that increasing the panel radius of curvature will increase impactor acceleration and will decrease the plastic deformation of panel, but if the radius of curvature is increased more and more, then the impactor acceleration will not increase further and will be nearly constant, on the other hand plastic deformation of the panel will not be increased further, when the panel radius of curvature is increased more.