metals as lightweight protection materials

... covering lightweight materials for warfighter protection as well as vehicle protection Topics ranged from ballistic threats to blast threats and from very hard to relatively soft armor materials ... models and data for choosing materials based on their ability to inhibit or avoid failure mechanisms as opposed to choosing them based on bulk properties as measured in quasistatic and dynamic tests ... importance of lightweight protection materials to the Department of Defense (DoD) mission, DoD should establish a defense initiative for protection materials by design (PMD), with associated funding...

Ngày tải lên: 05/03/2014, 12:20

... cloths  Sharp waste  Unsharp wastes Group assignment Solutions for medical wastes in Vietnam Public economics  Extremely infectious wastes  Surgical wastes 1.2.1 Hazardous chemical wastes  Expired ... Medical wastes are material in form of solid, liquid or gases which are eliminated from healthcare premises Medical wastes include injurious medical wastes and common wastes  Injurious medical wastes ... to Wikipedia Medical, known as clinical waste, normally refers to waste product that cannot be considered as general waste, produced from healthcare premises, such as hospital, clinics, doctors’...

Ngày tải lên: 23/09/2012, 15:38

... parts of aspects, analyze, interpret, evaluate and reason from it In some ways, these may be called communicative tasks as they involve sts’ feelings, attitudes, tastes and values as well as their ... to be easier than tasks which ask for irrelevant details • Tasks that require immediate responses tend to be easier than tasks which require a delayed response 15 Thus, this chapter has reviewed ... learning nts the tasks as well as the social specified engaged in task X?” and interpersonal or implied relationship between the in participants the task Table : six components of a task (proposed...

Ngày tải lên: 07/09/2013, 13:37

... person directing him to cease, by such date as shall be specified in the order, the activity in respect of which the permit or environmental impact assessment, as the case may be, is required (2) ... of waste or solid objects on the sea floor and protection of areas as of special importance for scientific or conservation purposes) (4) 51 The practical availability of alternative land based ... Environmental Protection (g) to the effect that no exemption of any specified kind has been granted under this Act in favor of any specified person; or (h) to the effect that any person was or was not...

Ngày tải lên: 17/02/2014, 10:20

... across at least some asset classes However, some studies suggest that credit ratings have not historically been comparable across asset classes • Increasing transparency may be more feasible and ... terminology that applies across at least some asset classes, the staff found that credit ratings historically have not been comparable across asset classes and it may not be feasible to attain this comparability ... methodologies for specific asset classes Standardized scenarios, however, could require the creation and mapping out of thousands of assumptions to achieve relevancy for each asset class, industry, geographic...

Ngày tải lên: 06/03/2014, 08:20

... low-cost and improved EMI shielding materials Experimental section Materials PVDF was used as polymer matrix with a molecular weight of 100,000 g.mol and it was purchased from Alfa Aesar MWCNTs were ... f-MWCNTs/PVDF composites alone in the same frequency region has been measured, and in this case, an EMI SE of 18 dB has been obtained as shown in Figure 10c Table shows the overall EMI SE of different ... was acquired using Perkin Elmer FTIR spectrometer from 400 to 4,000 cm-1 The chemical resistance of the composites in different acids, bases, alkanes and organic solvents was estimated by measuring...

Ngày tải lên: 21/06/2014, 05:20

... Removal of heavy metals from wastewater 277 adsorption to be a highly effective technique for the removal of heavy metals from waste stream and activated carbon has been widely used as an adsorbent ... heavy metals with a concentration range of 20–60 mg/l The results of using real wastewater showed that rice husk was effective in the simultaneous removal of Fe, Pb and Ni, whereas fly ash was effective ... increased from 26.04% to 67.917% i.e with the increase of the amount of absorbent concentration, while the Cd removal using fly Ash varied from 25.21% to 73.54% Case of study: treatment of wastewater...

Ngày tải lên: 20/07/2014, 12:47

... both increased and decreased numbers, perhaps because of different assays used to measure the size of this compartment Furthermore, in correlating disease progression with Tregs, the measure of ... ≈, approximately equal to normal controls; ↑, increased compared with normal controls; §BrdU labeling was too low to be determined The method by which cell turnover was assessed is indicated: BrdU, bromodeoxyuridine, ... cell depletion in disease progression However, in SIV-infected rhesus macaques, in which disease progression is generally faster than it is in HIV-infected humans, decreases in naïve CD4+ T cell...

Ngày tải lên: 06/08/2014, 19:21

... specimen was taken out of the beaker, any visible surface moisture was wiped off, and then it was weighed After this, the specimen was returned to the test tube and the uptake of water was measured ... procedure was, therefore, to expose the ethanol-swollen hydrogel to water/ethanol mixtures with increasing water concentrations, until pure water was used The extraction time was at least 30 for ... chemically bound to the glass stably rests on the substrate as a thin coating still capable to interact with cells This nanometric film was characterized by AFM measurements, as below described in...

Ngày tải lên: 11/08/2014, 00:22

... the material in shear In elastically isotropic materials, the elastic properties are the same in all spatial directions In this case, the elastic constants are related as follows: G= E 2(1 + ν) ... reason for this is the larger bond length of the metallic bond Because it is based on electrons in a widely spread electron gas, the interaction energy does not decrease as strongly with increasing ... same for all materials within a certain class As the second derivative of the energy determines the elastic properties, materials with a larger bond energy have to have a larger elastic modulus...

Ngày tải lên: 11/08/2014, 15:20

... that both load cases yield the same result for the energy release rate As long as the stress fields are the same, the energy release rate is independent of the load case This assumption from section ... plastic deformations occur in this region, whereas the rest of the specimen remains elastic and its strains are only small If the strain was measured locally, the difference would be smaller, as ... different materials: Linear-elastic (dashed line) and elastic-plastic (solid line) The figure shows the nominal stresses and strains (σnss , εnss ) and the maximum values in the linear-elastic (σmax,el...

Ngày tải lên: 11/08/2014, 15:20

... case, even when the experiment is stabilised by displacement control ∗ 5.3.4 Measuring elastic-plastic fracture mechanics parameters As in linear-elastic fracture mechanics, specimens in elastic-plastic ... the case, we enter the domain of elastic-plastic fracture mechanics (epfm) which can deal with a large plastic zone The method, however, cannot be used for arbitrarily large plastic zones – plastic ... this maximum, FQ = F5 is used as a critical value (figure 5.16(b)) In this case, it has to be ensured that plastic deformation was small enough to allow using linear-elastic fracture mechanics A...

Ngày tải lên: 11/08/2014, 15:20

... case Both classes of materials will now be explained Metals can also be strengthened by adding bres; this will be covered in chapter Coarse two-phase materials Coarse particles of a second phase ... pseudo-elastic strains of several percent, much more than usually possible for elastic strains in metals For this reason, the phenomenon is also called superelasticity One advantage of pseudo-elasticity ... increase in grain boundary energy is compensated by the decrease of the stored elastic strain energy from the decrease of the dislocation density The higher the dislocation density, the easier...

Ngày tải lên: 11/08/2014, 15:20

... stress is sufficiently large, a polymer can deform plastically even below the glass temperature In other words, as in the case of metals, the material has a yield strength The time-dependence is important ... viscoelastic and, at even larger strains, flows viscoplastically If the strain is increased further, plastic behaviour dominates, and the slope of the curves decreases If the loading time is increased ... temperature is not as distinctly defined as it is in a pure metal The degree of polymerisation also has an influence on the mechanical properties – with increasing chain length, amorphous thermoplastics become...

Ngày tải lên: 11/08/2014, 15:20

... energy elastic Tg viscous energy elastic viscous glass transistion Tm T T (a) Amorphous thermoplastics (b) Semi-crystalline thermoplastics E (log) E (log) glass transition energy elastic glass transition ... between energy-elastic and entropyelastic behaviour At lower temperatures, only smaller parts of the molecules can slide past each other as explained above As we approach the glass temperature, ... (see equation (C.3)), Young’s modulus of elastomers often increases with increasing temperature Contrary to metals and ceramics, the elastic strains in elastomers can become very large and attain...

Ngày tải lên: 11/08/2014, 15:20

... deforms plastically in the in-phase mode If we make the simplifying assumption that the matrix is perfectly plastic with a yield strength of σm,F , the compressive strength is [122] Rc,in phase = ... always smaller than in a crystalline one This explains why glass fibres cannot be as stiff as carbon fibres Accordingly, glass fibres are a reasonable choice if the strength of the composite is the main ... duromers not 10 To arrive at this number, it has to be kept in mind that a perfectly plastic material can absorb twice as much energy as a linear-elastic material at identical maximum stress and...

Ngày tải lên: 11/08/2014, 15:20

... 200 100 40 % C 50 40 % glass 20 % glass 10 % glass unreinforced 10 100 101 102 103 104 105 106 107 Nf Fig 10.25 Comparison of the S-N curves of unreinforced as well as glass- and carbon-reinforced ... stress decreases at the notch root To quantify this decrease, we define the relative stress gradient at the notch root 17 As we will see below, this is not true anymore as soon as linear elastic fracture ... static strength In high-strength metals, the fatigue limit increases only slightly within a material class (figure 10.21) The reason for this is that high-strength materials are very notch-sensitive,...

Ngày tải lên: 11/08/2014, 15:20

... strain-controlled loading (booth A), increasing the stiffness increases the elastically stored energy, whereas decreasing the stiffness increases the elastically stored energy in stress-controlled ... Booth A: WA ∝ EA Increasing EA increases WA and vice versa (el) (el) Booth B: WB ∝ 1/EB Increasing EB decreases WB and vice versa Figure 13.2 shows the stored elastic energy as area in the stress-strain ... this reason, these alloys can be used at 75% of their melting temperature, justifying the name ‘superalloys’ The volume fraction of the second phase in modern superalloys can be as high as 70%...

Ngày tải lên: 11/08/2014, 15:20