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Gravitational bullet injuries, prevalent in the Middle East, particularly in Iraq, are a critical public health concern, often resulting from celebratory gunfire. In our Neurosurgery Teaching Hospital in Baghdad, we've observed that these injuries differ significantly from high-velocity gunshot wounds, characterized by lower velocity and energy due to air resistance and gravity. Unlike high-velocity bullets, gravitational bullets cause less bone fragmentation and radial brain damage. These bullets often end up on the tentorium or within the skull base, rarely transgressing the cerebellar tentorium on a vertical trajectory. We've also noticed that the pediatric population, particularly younger children, are more susceptible to these injuries due to their thinner cranial vertex, leading to more penetrating injuries and aggressive brain bleeding. Our observations underline the need for focused studies, awareness, regulation, and tailored management strategies to combat this overlooked issue.

The validation of ocean color satellite retrievals generally relies on analyzing match-ups between in situ measurements and satellite retrievals. These analyses focus on the quality of the satellite data, however, of the same importance is the quality of the in situ data. Here, we present the spatial variability of in situ above-water reflectance (Rrs(0+)) within the spatial resolution of different ocean color satellites—300, 900, 1500, and 3000 m spatial resolutions, mimicking Sentinel 3 OLCI and MODIS-Aqua satellites, and possible 3 × 3 and 5 × 5 windows. Radiometric data was acquired with autonomous radiometric sensors installed in the British Columbia Ferry Services Inc. vessel “Queen of Alberni” from May to September 2019, crossing the optically dynamic waters of the Strait of Georgia, Canada. The dataset followed optimal geometry of acquisition and processing, including corrections for skylight radiance signals, ship superstructure, the non-isotropic distribution of the water-leaving radiances, and quality control. A total of 33,073 spectra at full resolution, corresponding to 10 days, were considered for the analysis presented here. The results showed that, overall, the subpixel variability increased as the spatial resolution of the sensor or the window size increased, mainly in a linear fashion. Specifically, spatial variability of Rrs(0+) was the largest (∼18% and 68% for 900 and 3000 m pixel resolution, respectively) in Near Field Plume Interface waters, followed by in the Ocean Water Interface (∼28% and 35%, respectively), thus indicating spatial heterogeneity of interface waters. Further, we found that the estuarine waters showed higher subpixel Rrs(0+) variability (∼8% and 16% for 900 and 3000 m, respectively) compared with plume and oceanic waters. We showed that the high spatial variability in Rrs(0+) was primarily associated with the spatial dynamics of the optical water constituents, thus limiting the use of these datasets as Fiducial Reference Measurements and for validation of satellite-derived atmospherically corrected reflectance. We suggest that spatial variability of the in situ Rrs(0+) should also be considered in the selection criteria for good match-up data, especially for data acquired in coastal dynamic systems. As a result, it will advocate for the exclusion of interface or transition water pixel grids in order to avoid compromising the statistical result of satellite validation.

The Neoproterozoic basement rocks in Ar Rayn terrane set as parts in the Eastern Arabian Shield. It focus the petrological and kinematic vorticity for high deformed volcanic and granitoids rocks in the Al-Amar locality. The volcanic rocks divide into two main series, the eastern sequence cycle represents dacite, rhyodacite, rhyolite and ignimbrites, and the western sequence cycle characterizes andesite and pyroclastics. Furthermore, the granitoids rocks content monzodiorite, tonalite, granodiorite and alkali-feldspar granite. For assessing the proportions of pure and simple shear contributions in penetrative deformed rocks, the kinematic vorticity number (Wm) to the mean appreciation by applying porphyroclast, rotating in a flowing matrix is crucial. In the Ar Rayn terrane of Arabian shield, kinematic vorticity numbers for high deformed metavolcanics and granitoids gneisses vary from 0.4 to 0.6. The deformation in the studied area varied from simple shear, according to vorticity and strain studies. Nappe stacking getting ready during the thrusting activity only through the Al Amar –Idsas fault, according to the results, most likely due to brittle imbrication. A penetrative sub-horizontal foliation formed sub-parallel to the nappe contacts with the beneath laying nappes, showing that the ductile strain was superimposed on the construction of the nappe under high pressure. The Ar Rayn terrane was created sub-horizontal foliation by the buildup of ductile strain during under plating, which was induced by a vertical shortening component. This foliation was formed in the majority of cases during the thrusting nappes upon each other, implying that nappe stacking was related to vertical shortening due to a massive scale by the active Al Amar –Ideas fault.

The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.

Aluminum matrix composites are widely used in many structural application due to properties like high specific strength, wear resistance, lightweight and fatigue properties. The aim of the current work is to investigate the effect of the addition of nanosize participles to AA6063-T4 aluminum alloy on the electrical conductivity, magnetic and fatigue properties of composites produced by stir casting method. It was revealed that the AA6063-T4/ composites were successfully prepared with 3 wt%, 5 wt% and 7 wt% TiO2 using a stir casting technique with electrical conductivity increasing with increasing amount of Also it was found that the electrical conductivity of all composites was higher than the base metal matrix and the conductivity was proportion to the frequency for both matrix and composites. The magnetic studies revealed an improvement of the nanocomposites in comparison with the base metal. The fatigue life and fatigue strength of 7 wt% TiO2 composite was found to be higher than that of other composites and base matrix.

Vertical electrical soundings, seismic refraction tomography, and ground magnetic measurements were taken or conducted close to an open dumpsite near Khamis Mushait, southwestern Saudi Arabia, which is characterized by shallow groundwater conditions. Structurally, intersected series of north- to northwest-trending faults affect the area. A new urban expansion and the Khamis Mushait industrial zone are close to the open dumpsite. This study evaluates the potential for leachate intrusion into groundwater aquifers. The results of electrical soundings reveal four geoelectric units: the topsoil, weathered layer, partly weathered/fractured basement, and fresh basement bedrock. At the dumpsite, relatively low resistivity values that are less than 30 Ωm characterize the topsoil, weathered layer, and partly weathered/fractured basement because of conductive leachate from the dumpsite. Besides, the results of ground magnetic data indicate that the deformation of varying intensities affects the dumpsite area, resulting in fractures developing in the N–S, NE–SW, NW–SE, and, to a lesser extent, E–W directions. Moreover, geoseismic tomographic models illustrate a low P-wave velocity zone corresponding to a low resistivity zone, and a NE–SW fault was identified from geoseismic cross-sections. Finally, these fractures and faults could become contaminant pathways for shallow aquifers around the dumpsite. To minimize the impact of such leachate, from a dumpsite, on groundwater quality and the environment in general, the dumpsite must be properly designed, constructed, and managed using engineering principles.

The upper plutonic rocks in southwestern Saudi Arabia has been mapped through Landsat 8 Operational Land Imager (OLI) data. The gathered field rock samples were subjected to spectral measurements (in the range of 0.4–2.5 µm) in the laboratory using a GER 3700 spectroradiometer. Integrated remote sensing techniques, including the band ratio, principal component analysis (PCA), and Gram-Schmidt spectral sharpening have been applied through this study. The red–greenblue composites of the pan-sharpened original bands (3, 4, and 7), principal components (PC3, PC1, and PC2), and band ratios 5/6 and 5/7 were found to be the most useful to delineate the study area’s Upper Proterozoic plutonic rocks. The results of image processing methods, spectral reflectance analyses are in good agreement with the field data. The spectral reflectance curves of the collected samples and the corresponding Landsat 8 pixels match well. It is indicated that Landsat-8 image data has great capability to identify lithological units and could be applicable in several areas in arid and semiarid environments.

An attempt was made to synthesize aluminum alloy (AA) 7075 matrix reinforced with 0, 1, 3, 5 wt% Al2O3 particulates by using stir casting technique. Mechanical properties and wear behavior were examined. The hardness and tensile properties were obtained before and after addition of Al2O3 particulates to reveal the extent improvement. Wear behavior was examined by using a pin-on-disc device to validate the improvement of the wear resistance. The results showed that adding of Al2O3 reinforcement were significantly enhanced the mechanical properties. The ultimate tensile strength (UTS) and yield tensile strength (YTS) were observed 133 MPa, 35 MPa for the unfilled aluminum matrix, whereas 152 MPa and 47 MPA were achieved at 5 wt% Al2O3 nanocomposites which resulted in 14.3 and 34.3% improvement, respectively. The hardness was observed 57 BHN and 72 BHN at 0 wt% and 5 wt% Al2O3 respectively, resulting in an improvement of 26.3%.

This research is devoted to study the influence of different weight percent concerning to the additions of Ti and Cu on mechanical and tribological properties of AA6061. The composite materials consist of different weight percentage of Ti (0.2, 0.4, and 0.6) wt% and constant weight percentage of Cu (0.2) wt% which were fabricated by liquid metallurgy route technique. Microstructural characterization and phases have been examined by using SEM (scanning electron microscopic).SEM examination showed uniform distribution of nano Ti and Cu in AA6061. The consequences of mechanical tests demonstrated clear enhancement in mechanical properties, such as ultimate tensile strength, yield strength, young modulus, ductility% and hardness at additive percentage of 0.4% Ti+0.2%Cu nano particles incorporated into molten AA6061. Percentage of enhancement ultimate tensile strength is about 73.3%, yield strength about 82.7%, young modulus is about 21.2%, the Vickers hardness about 42.6% and the decreasing in ductility was about 25.2% compared with the metal matrix (AA6061). The wear rate test was performed by using pin on disc rig for both hybrid nano composite and base metal (AA6061) under various loads (10,15and 20) N with sliding speed (1.282) m/sec at a (10) min’s time. The results showed a decrease in wear rate at 0.4%Ti+0.2%Cu compared with the base metal (AA6061). Improvement percentage of wear rate is about 105% at 20 N load.

Landslides hazard as one of the major environmental threats of the Neom promising city in northwestern Saudi Arabia has been assessed through data integration of several sources including topographic, geologic, and seismologic data sets. Moreover, Landsat imagery and historical landslide data are introduced in assessing landslide susceptibility of the study area. All these data oriented to generate eight thematic layers representing eight landslide conditioning factors. These factors arranged according to their relative importance for landslide susceptibility mapping as follows: slope angle, elevation, curvature, aspect, earthquake density, fault density, drainage density, and lineaments density. These factors were assessed using GIS through a numerical rating scheme for thematic layers. The ranks and weights were given in association with intensive field studies and authors’ experiences. The estimated values of Landslide Potential Index (LPI) varies from 32 up to 107. Then, the resultant landslide susceptibility map classifies the landslide hazards into three relative classes of susceptibility: high, moderate, and low. Furthermore, this map was tested through several field checks and the extracted historical landslides within Neom area as well. This landslide susceptibility map will boost decision-making authority while executing the developing projects throughout the Neom promising area either avoiding strategic facilities or applying corrective geotechnical procedures to minimize the landslide hazardous impact for Neom city.

Southwestern Saudi Arabia is enriched with fractured and highly-weathered igneous and metamorphic rocks that function as the limited aquifer and supply significant quantities of water for household use and agriculture in this area. Twenty-seven groundwater samples were collected from shallow-dug wells and physio-chemically examined. It is displayed that, however the average value of total dissolved solids (792.67 mg/l) is not curiously high, the ionic component moved toward anthropogenic origin of pollution. The water in the area fits SO4–Cl type facies. The aquifer fractured properties and the existence of groundwater at near-surface depths affecting the groundwater hydrochemistry for the investigated area. Decision and policymakers must consider these results to minimize the environmental impact of local pollutants in the region.

Introduction: Choriocarcinoma is a rare gestational trophoblastic neoplasm with a high risk of pulmonary, hepatic, and, rarely, cerebral metastasis. We report a rare case of intracerebral haemorrhage as an initial manifestation of metastatic choriocarcinoma. Case presentation: A 33-year-old female with a history of multiple abortions, ectopic pregnancy, and complete hydatidiform mole presented with a disturbed level of consciousness. Emergency brain computed tomography (CT) scan revealed an intraventricular haemorrhage (IVH) and a left frontoparietal, non-traumatic intracerebral haemorrhage (ICH) with a significant midline shift. The patient underwent emergency evacuation of the hematoma and histological evaluation revealed choriocarcinoma. Later investigations revealed evidence of systemic metastasis. The patient underwent chemoradiotherapy and recovered well. Conclusion: Metastatic choriocarcinoma should always be in the differential of non-traumatic intracerebral haemorrhage in a female child-bearing age. Also, the pathological diagnosis should always be performed in cases of ICH of an unknown source.

One of the important aspects of mechanical design is improving fatigue life.; In this work, the effect of Ultrasonic impact treatment (UIP) and shot peening (SP)on constant cumulative fatigue life and fatigue strength of AA7075-T6 were studied; The sample group was machined and primed, and some specimens were treated using ultrasonic impact therapy (UIT) with one line of peening. Fatigue experiments were conducted under constant and variable amplitude (R=-1) at ambient temperature to determine the fatigue life of the S-N curve and fatigue strength during treatment 3.46% and 8.57% at 107 cycles for (UIT) and (SP). Cumulative fatigue damage testing was carried out for two steps loading it is observed that the fatigue life for SP and UIP treated specimens was improved compared to the unpeeled results. The fatigue endurance limit was enhanced by 35% for UIT and 54% for SP. The fatigue life for both treatments was much improved compared to as-received metal. These results also show a strong tendency of increasing fatigue strength after application of (UIT) and (SP) with an increase in mechanical properties of the material used. Conclusion • The constant fatigue properties are considerably enhanced by (UIT) and (SP) techniques. The fatigue strength at 107 cycles is improved by 3.46% and 8.57% for UIT and SP respectively. • Cumulative fatigue life was increased by 13.9 percent and 12.6 percent for low-high and high-low loading by UIT, respectively, while 36.6 percent and 22.3 percent were increased for low-high and high-low loading by SP, respectively, and fatigue life was improved by 36 percent and 54 percent for UIT and SP. • The (UIT) and (SP) techniques are a suitable method for hardening the surface of metals due to the formation of a hard layer by increasing compressive residual stresses. • The Miner theory does not follow the conservative and detailed prediction of the life of certain fatigue specimens

Silicon carbide (SiC) is a technologically significant material. A recent report on the abundance of C60 fullerenes in interstellar space, along with the presence of SiC precursors, sparked interest in potentially similar SiC nanostructures. C60 fullerene was found experimentally and is an exceptionally stable form of carbon. As Si and C have similar valence electron properties, it has been long envisioned that Si and SiC could also form similar fullerene-type structures. In this paper, Si30C30 fullerene-derived clusters were studied from the first principle, starting from an ideal Si60 fullerene template with various arrangements of silicon and carbon atoms and then relaxing them without any symmetry constraint. Hydrogen passivation was considered as well to model the effect of ligands that may be available during chemical synthesis processes. We have found that, after passivation, the relative stability of different configurations of Si30C30 clusters changed compared to the unpassivated structures, while some structures collapsed. We have also noticed several Si–Si and Si–C double bonds in the unpassivated structures. Upon relaxation, some Si atoms lost their hydrogen, while carbon atoms capture those hydrogen atoms. Finally, we tested the endohedral doping of a transition metal, tungsten atom, to stabilize and magnetize Si30C30. With hydrogen passivation, the magnetic moment on W atom was enhanced. Overall, the effects of passivation on these fullerene structures are not very straightforward.

This paper presents the effect of temperature on the fatigue properties of carbon steel containing three different content of carbon: 0.758%C, 0.539%C and 0.319%C. The tests were conducted at room temperature and at variable temperatures. The temperature cycle used was in the range from 50oC to 100oC and 150oC respectively. Using constant amplitude loading, the fatigue test was done by rotating bending machine. The results obtained from the fatigue test at room temperature were compared with the fatigue test results at variable temperatures. A modified Miner rule was applied to predict the fatigue life at variable temperatures and to evaluate the fatigue damage in every steel alloy. The fatigue damage was determined as the number of cycles and stress. The results showed that the alloy steel with 0.539%C had the best resistance to the constant applied load and variable temperature and it was also found that the fatigue life of all three alloys decreased at variable temperature compared to room temperature.

Cool roofs use reflective materials or coatings to reflect a portion of the incident solar radiation. This results in a lowering the surface temperature of the cool roof compared to black roofs, and thus helps reduce the cooling energy loads during the summer season. The research reported in this paper was conducted to assess experimentally and numerically the performance of cool and black roofs that were subjected to the hot, humid and dusty climate of Jubail Industrial City (JIC). This paper focused on characterizing one of the important properties of reflective coating material (RCM), which is its solar reflectivity. In this study, the effect of dust/dirt accumulation on the solar reflectivity of the RCM was investigated at different exposure times to the natural weathering conditions of JIC. The test results showed that dust and dirt can significantly contribute in reducing the solar reflectivity of the RCM. As such, a number of cleaning processes were conducted on the surface of the RCM so as to increase its solar reflectivity. The effect of each cleaning process on the solar reflectivity of the RCM was investigated. Finally, this paper provides a test protocol and procedure for characterizing the dust concentration/intensity on the surfaces of the RCM and cleaning this material after different exposure times to a natural and polluted climate.

The effect of fungi colonies on fatigue of 7075 aluminum alloys was studied for specimens corroded at different media. 57 specimensof aluminum alloys were submerged in Shat-Arab water (Sh.A.W) for four months at different conditions (at light media (9 fungi colonies), dark media (80 fungi colonies))and then applying constant fatigue tests after removing the specimens from the corrosion media . The results show that the fungi colonies can corroded Al alloy the reduction of pre-corroded specimens at light media (9 fungi colonies) was 13% and for specimens at dark media (80 fungi colonies) was 22% , and a nonlinear damage model was proposed to predict the cumulative corrosion fatigue life

Improving fatigue life is one of the most important issues in mechanical design; an investigation has been conducted on Al 2017-T4. Group of samples have been machined and prepared, some of specimens have been treated using the ultrasonic impact treatment (UIT) with one line peening. The fatigue tests were carried out under constant and variable amplitude (R=-1) at ambient temperature, in order to find out the fatigue life S-N curve and strength after treatment. It has been found significant increasing in strength after it was treated by (UIT). The fatigue strength is improved after treatment up to 4.16% at 107 cycles, enhancement are present with 24% and 18.78% for the cumulative fatigue lives low-high and high–low respectively. These results also show a strong tendency of increasing of fatigue strength after application of (UIT) with increase in mechanical properties of material used.

Abstract In this paper, fatigue damage accumulation were studied using many methods i.e.Corton-Dalon (CD),Corton-Dalon-Marsh(CDM), new non-linear model and experimental method. The prediction of fatigue lifetimes based on the two classical methods, Corton-Dalon (CD)andCorton-Dalon-Marsh (CDM), are uneconomic and non-conservative respectively. However satisfactory predictions were obtained by applying the proposed non-linear model (present model) for medium carbon steel compared with experimental work. Many shortcomings of the two classical methods are related to their inability to take into account the surface treatment effect as shot peening. It is clear that the new model shows that a much better and conservative prediction of fatigue life in comparison with CD and CDM methods. The prediction of the present model gave slightly below the experimental data while the CDM gave overestimate prediction and CD showed strongly underestimates the life of specimens. Keywords: Cumulative fatigue damage, Shot peening, Non-linear model.

In this paper, fatigue damage accumulation were studied using many methods i.e.Corton-Dalon (CD),Corton-Dalon-Marsh(CDM), new non-linear model and experimental method. The prediction of fatigue lifetimes based on the two classical methods, Corton-Dalon (CD)andCorton-Dalon-Marsh (CDM), are uneconomic and non-conservative respectively. However satisfactory predictions were obtained by applying the proposed non-linear model (present model) for medium carbon steel compared with experimental work. Many shortcomings of the two classical methods are related to their inability to take into account the surface treatment effect as shot peening. It is clear that the new model shows that a much better and conservative prediction of fatigue life in comparison with CD and CDM methods. The prediction of the present model gave slightly below the experimental data while the CDM gave overestimate prediction and CD showed strongly underestimates the life of specimens.

In this present work, the behavior of AA7349 aluminum alloy under constant and cumulative creep-fatigue interaction has been studied by using an electrical system designed and built in order to investigate creep-fatigue interaction at different stress levels and temperatures. An hour-glass shaped specimen of AA7349 aluminum alloy has been subjected to a constant and variable creep-fatigue tests performed under rotating bending loads and stress control at stress ratio R=-1.The results of the creep –fatigue life have been studied byMiner rule and compared with the proposed and experimental methods. It was shown that theMinerrule and proposed modelgive reasonable results and they are in a good agreement with the experimental fatigue lifetimes.

Degassing technique currently applied to cast aluminum alloys due to its technological and economic advantages. The present work aimed to study the effect of degassing technique of cast aluminum alloy (LM2) under different pressures using squeeze casting process. Inert argon gas was pumped into the molten aluminum with flow rate (2,5-5-7)l/min. at constant pumped duration (5min.). Different applied pressures were used(17, 35, 52) MPa. The test was performed at room temperature. The physical and mechanical properties of degassed samples were measured and compared with non-degassing (ND) samples. The results showed that the best condition of degassing is found at 2.5 l/min flow rate and 35 MPa applied pressure. It was found that a slight difference is observed for the density and the lowest value of porosity was obtained at 2.5 l/min flow rate and 52 MPa applied pressure.

Abstract In this investigation, Al2O3 nano material of 50nm particles size were added to the 6061 Al aluminium alloy by using the stir casting technique to fabricate the nanocomposite of 10wt% Al2O3. The experimental results observed that the addition of 10wt% Al2O3 improved the fatigue life and strength of constant and cumulative fatigue. Comparison between the S-N curves behaviour of metal matrix (AA6061) and the nanocomposite 10wt% Al2O3 has been made. The comparison revealed that 12.8% enhancement in fatigue strength at 107cycles due to 10wt% nano reinforcement. Also cumulative fatigue life of 10wt% nanocomposite was found to be increased by 33.37% and 39.58% for low-high and high-low loading sequences, respectively, compared to the metal-matrix cumulative life. Keywords: Al2O3 nanoparticles, AA6061/10wt%, constant and cumulative fatigue, MMCs.

In this work, constant and increasing temperature fatigue interaction effect on fatigue behavior of 2017-T4 aluminum alloy was investigated. Fatigue tests at constant load constant temperature and constant load increasing temperature were performed for five applied stresses which are (350,275,200,175 and 150 MPa) that based on the tensile test behavior .The constant temperatures were room temperature (RT) (25 ̊C) and 100 ̊C. While the increasing temperatures were RT, 50 ̊C, 100 ̊C and 150 ̊C for one test program. The constant fatigue property of the increasing temperatures was observed the worst case compared to the others constant fatigue properties. A new variable temperature fatigue damage model was proposed. It is based on the S-N curve and taking into account the effects of constant loads and variable temperature. A comparison between prediction of the proposed model and crack growth rate due to Miner rule was made. The results proved that this model is satisfactory and gave safe results than Miner rule compared to experimental data.

There is a general interest in increasing the fatigue life of materials. Shot peening is the process commonly used in order to increase the fatigue strength and life of 7075-T651. The effect of a combination of processes, fatigue-creep interaction and shot peening has not been thoroughly investigated so far. The aim of the present investigation was whether further improvements can be achieved by a comb/*ination of the two treatments. Two level experiments (cumulative fatigue damage programe) were used in order to determine the optimal set of process. It was found that the combination of shot peening and fatigue-creep interaction could be applied successfully in order to increase fatigue life for some specimens. Results of variable loading test clearly indicate that Miner rule does not give accurate and reliable predictions on fatigue lives.

The purpose of the paper is to present a study of the effect of the ply orientation angle on the crushing behavior, energy absorption, specific energy absorption, and failure mode of woven glass fiber/polyester laminated composite tube. Glasspolyester tubular specimens with circular cross-sectional geometry and (+45˚/-45˚, +60°/-30°, 0°/90°) fiber orientation angles were fabricated and crushed by quasistatic test under the same condition to examine the energy absorption characteristics and to calculate the crashworthiness parameters. The loaddisplacement curves of the tested tubes were presented and described; several failure modes of the crushed tubes were observed and discussed. It has been found that the fiber orientation angle has a considerable effect on the crushing characteristic of the collapsed tubes and the failure mode, and (0°/90°) fiber orientation angle tubes exhibit the highest SEA (specific energy absorption) 33.108 kJ/kg, crush force efficiency (0.7), crush strain relation (0.81) and a load/deformation curve closer to the ideal curve than the other specimens.

The aim of this work is to study the influence of the temperature on the ultimate tensile strength (UTS) of composite material which is manufactured from polyester and E-glass (woven roving, chopped strand mat) as a laminate with a constant fiber volume fraction (VF) of 33%. The results showed a little effect of temperature on tensile strength in the range of room temperature (RT) to 50 oC for laminates reinforced with E-glass (woven roving) [0/90, ±45,0/90], [0/90]3, and [0/90, CSM, 0/90], but for laminates reinforced with E-glass chopped strand mat (CSM), as [CSM] 3 and [CSM, 0/90, CSM], a continuous reduction in strength was observed with increasing temperature from (RT) to 60 oC. The highest percentage reduction in strength was 23% at 60oC as compared with (RT) for [CSM]3 laminate

The fatigue-creep interaction performance of 5086 and 6061-T651 aluminum alloys were investigated for specimens tested under control stress rotating bending at a stress ratio R=-1 and 250°C temperature. The fatigue endurance limit for both alloys reduced at 250°C. The fatigue and creep damage was evaluated based on the linear damage rule, where the fatigue damage was determined as the number of cycles to failure and the creep damage was evaluated based on the time applied experimentally for low to high and high to low amplitude stress. The cumulative fatigue-creep interaction damage was found to around 0.5 i.e DF +Dc =0.5 Fatigue – creep interaction lives predicted by the linear damage rule were compared to the actual lives. The results show that the linear damage rule gave an overestimated predictions.

The aim of this work is to study the influence of the type of fiber glass mat on fatigue behavior of composite material which is manufactured from polyester and E-glass (woven roving, chopped strand mat (CSM)) as a laminate with a constant fiber volume fraction (VF) of 33%. The results showed that the laminates reinforced with E-glass (woven roving) [0/90, ±45.0/90] and [0/90, CSM, 0/90] have lower fatigue strength than the laminates reinforced with E-glass [0/90]3,[CSM]3 and [CSM, 0/90, CSM] although they had different tensile strength; the best laminate was [0/90]3 .

For semigroups of linear bounded operators on Hilbert spaces, the problem of being in Cp , 0 Keywords

Fatigue tests were done to determine the S-N curves for Cu 65400 alloy specimens .The effect of laser shotting on the fatigue properties were investigated with stress ratio R=-1 at room temperature. Laser shotting of this alloy increases the life, endurance limits and compressive residual stresses. The largest increase in compressive residual stresses were observed at stress level 350 MPa.

In the present work simulation of impact response using LS-DYNA explicitfinite element code is described to investigate the crash behavior and energy absorption characteristics of square glass fiber reinforced plastic tubes, subjected to impact load. Filament-wound tubes with two layers [+45º, -45º] were fabricated and tested. The experimental crushing characteristics data are compared with the obtained numerical results, showing good agreement. The effect of geometrical parameters, winding angle and the failure mode on the energy absorption characteristics are also investigated.

A series of constant and cumulative fatigue tests under the effect of shot peening were conducted for two aluminum alloys 2024 and 5052. Three unpeed specimens were tested for each alloy under low-high stress levels (120-280 MPa) for 2024 aluminum alloy and (40-90 MPa) for 5052 aluminum alloy at room temperature and stress ratio R= -1. Other specimens were exposed to shot peening with different blasting time before the cumulative fatigue testing. It is found for 2024 Al alloy that as the shot peening time increases the cumulative fatigue life is improved but above 10 min. the life is reduced. For 5052 Al alloy the cumulative fatigue life is reduced as shot peening time increases

Residual stresses play an important role in the behavior of structuressubjected to static and dynamic loads. The main aim of this study is to estimate experimentally the residual stresses in 70/30 brass material tested in bending and torsion using the plasticity theory. The influence of shot peening process on the tensile residual stresses is discussed. It is shown that the shot peening strongly influences the residual stresses, i.e. shot peening will reduce the tensile residualstresses by 13.6% of the yield strength in bending tests. While will reduce the tensile residual stresses by 22% of shear yield stress in torsion tests.

This work describes an attempt has been made to study the effect of temperature on fatigue behavior of polyester reinforced with woven of fiber glass manufactured as a laminate [CSM]. Fatigue tests were carried out at constant stress amplitude at different temperature environment. All fatigue tests were employed at stress ratio R=-1 and under constant fiber volume fraction (VF) of 33%. The results indicated that the tensile and the fatigue strength decreased with increasing temperature up to at 60oC.The fatigue life reduction factor (FLRF) at 60oC was in range (41%-61%) in range of applied stresses amplitude between (80-100MPa) compared at (RT).

Fatigue damage and life results from the conjoint actions of cyclically applied stress and external environment (chemical) are studied for aluminum (3003-H18) alloy to explore load-environment interaction in fatigue which is essential to the formulate rational life prediction of component and structures. In this study, a modified corrosion-fatigue model (MCFM) based on the S-N curve and taking into account the effect of load history and corrosion effect was introduced. The obtained results from this model are in good agreement with the experimental results and show a 2.492 safety factor while Palmgren-Miner (PM) rule gave 1.372 factor of safety. The corrosion environment reduces the fatigue endurance limit by 5.06% compared to dry fatigue.

The effect of different shot peening time (SPT) on the rotating bending fatigue behaviour of austenitic stainless steel TP321 was studied. The fatigue improvement with respect to the unpeened condition was discussed. Shot peening treatments employing steel balls determine a remarkable increment of the high-cycle fatigue limit of austenitic stainless steel ranging between 4% and 15% . such improvement can be essentially attributed to the compressive residual stresses deduced by the treatment in the surface layers . While the life improvement factor (LIF) was increased by a factor ranging between 1.72 to 5.3. All these improvement were happened up to 20 min shot peening time (20 SPT).

A sensitive and selective method has been developed for the determination of palladium(II) and nickel(II). A new reagent and two complexes have been prepared in aqueous solutions. The method is based on the chelation of metal ions with 4-(4'- antipyriyl azo ) -2-bromo phenol (APBP) to form an intense color soluble products, that are stable and have a maximum absorption at 498 nm and at 433.5 nm and εmax of 0.21×104 and.0.38×104 Lmole-1cm-1 for Pd(II) Ni(II) respectively. A linear correlation of (0.2 - 3) and (0.6 -2.2) ppm for Pd(II) Ni(II) respectively. The stoichiometry of both complexes was found to be 1:2 (metal:ligand). The effect of various cations and anions on Pd(II) and Ni(II) determination have been investigated. The stability constants Pd(II) and Ni(II) were 0.37×108, 0.38×108 L mol-1 respectively. The conductivity measurements for complexes are consistent with those expected for an electrolyte. The optimum conditions for full color development for described methods were applied satisfactorily to synthetic mixtures samples and biological samples.

A design of rubber components against fatigue failure is one of the critical issues to prevent the failures during the operation .Therefore; fatigue life prediction was the key technologies to assure the safety reliability of mechanical rubber. In present study, mechanical properties of natural rubber and fatigue life (constant amplitude stresses) were carried out experimentally at room temperature and 40 oC. The mechanical properties and constant fatigue life were compared with previous study. Tensile and Fatigue life tests were performed using Dumb-bell specimens. The experimental mechanical properties and fatigue life of natural rubber component agreed fairly with the published data of previous study above. While the mechanical properties and fatigue lives at 40 oC were decreased with about 33% of tensile properties at 0.2 strain and about 99% fatigue properties at 5x106 cycles compared with room temperature.