Impact Strength Of Glass And Glass Ceramic

Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicatc glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.Mechanical Engineerin

Improved Bar Impact Tests Using A Photonic Doppler Velocimeter

Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and a glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression, and the >steady state> strength. For borosilicate glass and soda lime glass, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic (25% spinel) was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic, as opposed to intrinsic property.Mechanical Engineerin

Sand Penetration By High-Speed Projectiles

Tungsten projectiles were shot into sand at velocities between 600 and 2200 m/s. Penetration was maximum at about 775 m/s. Below that velocity, projectiles were apparently stabilized by a fin set. Above that velocity, projectiles were broken by transverse loads. High-speed penetration resulted in comminution of sand particles, reducing their size by about 1000 times.Mechanical Engineerin

X-Ray Tomography To Measure Size Of Fragments From Penetration Of High-Velocity Tungsten Rods

Behind-armor debris that results from tungsten rods penetrating armor steel at 2 km/s was studied by analysis of recovered fragments. Fragment recovery was by means of particle board. Individual fragments were analyzed by x-ray tomography, which provides information for fragment identification, mass, shape, and penetration down to masses of a few milligrams. The experiments were complemented by AUTODYN and EPIC calculations. Fragments were steel or tungsten generated from the channel or from the breakout through the target rear surface. Channel fragment motions were well described by Tate theory. Breakout fragments had velocities from the projectile remnant to the channel velocity, apparently depending on where in the projectile a fragment originated. The fragment size distribution was extremely broad and did not correlate well with simple uniform-fragment-size models.Mechanical Engineerin

Optimal guidance law development for an advanced launch system

The proposed investigation on a Matched Asymptotic Expansion (MAE) method was carried out. It was concluded that the method of MAE is not applicable to launch vehicle ascent trajectory optimization due to a lack of a suitable stretched variable. More work was done on the earlier regular perturbation approach using a piecewise analytic zeroth order solution to generate a more accurate approximation. In the meantime, a singular perturbation approach using manifold theory is also under current investigation. Work on a general computational environment based on the use of MACSYMA and the weak Hamiltonian finite element method continued during this period. This methodology is capable of the solution of a large class of optimal control problems

Spatial Distribution of Trace Elements in Rice Field at Prafi District Manokwari

Mapping spatial variability of trace elements in rice Ḁeld is necessary to obtain soil quality information to en-hance rice production. ἀis study was aimed to measure concentration and distribution of Zn, Cu, Fe, Pb, and Cd in two diᴀerent sites (SP1, SP2) of PraḀ rice Ḁeld in Manokwari West Papua. ἀe representative 26 soil samples were analysed for their available trace metal concentration (DTPA), soil pH, and C-organic and soil texture. ἀe result indicated that Fe toxicity and Zn deḀcient problems were encountered in both sites.  Rice Ḁeld in SP2 was more deḀcient in Zn than SP1. Site with the highest trace elements (Zn, Fe, Cu, and Cd) concentration had low soil pH and high C-organic. Acidic soil has higher solubility of metals; while high C-organic could improve the formation of dissolve organic carbon-metal binding, hence it improving the trace metals concentration in soil solution

Production of high pressures with a magnetic pinch.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1968.Bibliography: leaves 45-48.M.S

Geophysical Research

Contains reports on two research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)National Aeronautics and Space Administration (Grant NGR-22-009-131)National Aeronautics and Space Administration (Grant NGR-22-009-114)National Aeronautics and Space Administration (Contract NAS 12-436

Souvenir Purchase Motivations and Product Attribute Preferences among Arts and Design Students amidst Covid-19

Despite the onslaught of COVID-19, people still travel and tourism can only thrive further upon its end. Souvenir shopping has long been integral to the tourism business and one’s travel experience. This quantitative non-experimental descriptive correlational study aimed to determine the relationship between souvenir purchase motivations and product attribute preferences among the randomly selected 50 Grade 12 Arts and Design students in the University of San Carlos South Campus for the school year 2021-2022. Two standardized and reliable Likert-type survey tools were used to collect data. Results revealed that students acquire souvenirs for a variety of reasons before making their decision. Students also valued the portability, aesthetic value, and authenticity of an item when looking for a souvenir. Researchers found out that there is a high positive correlation between souvenir purchase motivations and product attribute preferences and the relationship between the two variables is found to be significant, r (48) = 0.547, p < 0.05. This means that students who go on trips have distinct motivations and it affects their decision-making towards purchasing souvenir items. This study recommends that the variables be tested in more settings post-pandemic, as travel restrictions ease worldwide