Evaluation of test methods and instrumentation for determining compliance with the Federal Standard for diagnostic X-ray equipment

Seed predation by weevils (Coleoptera: Curculionidae) has been implicated as a limiting factor in oak recruitment throughout eastern US forests. We examined the effects of weevil seed predation on American chestnut (Castanea dentata (Marsh.) Borkh.). Although an introduced pathogen eradicated sexually reproducing populations of American chestnut in the early 1900s, the recent development of a blight-resistant hybrid makes reintroduction feasible. We nondestructively assessed the amount of weevil damage to seeds using X-ray imagery and traditional float test methods in American and blight-resistant hybrid chestnut. We quantified the effects of weevil damage on seed germination and seedling growth. The float test method misidentified damage for up to 50% of seeds, whereas the X-ray method misidentified only 3% of the sample. Germination declined with damage: the smallest damage level reduced germination from 94% to 32%. No seeds with >50% damage germinated. Weevil damage reduced seedling growth by 50% compared with undamaged seeds. Seedling size increased with seed size, but seed size had no effect on germination. Our results highlight the importance of orchard and seed processing practices that prevent weevil damage to chestnut seeds. Because they drastically reduce germination rates and seedling growth, weevils have the potential to limit seed regeneration and dampen rates of spread in populations following reintroduction.

Download Full-text

Alkali Activated Paste and Concrete Based on of Biomass Bottom Ash with Phosphogypsum

Applied Sciences ◽

10.3390/app10155190 ◽

2020 ◽

Vol 10 (15) ◽

pp. 5190

Author(s):

Danutė Vaičiukynienė ◽

Dalia Nizevičienė ◽

Aras Kantautas ◽

Vytautas Bocullo ◽

Andrius Kielė

Keyword(s):

Compressive Strength ◽

Sodium Hydroxide ◽

Sodium Hydroxide Solution ◽

Bottom Ash ◽

Control Sample ◽

Test Methods ◽

X Ray ◽

Hydroxide Solution ◽

Fine Grained ◽

Alkali Activated

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.

Download Full-text