Fracture energy approach for the identification of changes in the wood caused by the drying processes

Specific fracture energy measurements were applied to identify changes caused by wood-drying processes of solid wood. Specimen design and geometry as well as parameters and specifications for a fracture energy test were determined experimentally. The specific test set-up was applied on plantation teakwood sample sets of standard as well as alternating convection kiln dryings and one oven drying. The results show that alternating changes of the drying temperature along with the equilibrium moisture content (EMC) in a kiln schedule have a small but significant decreasing effect on the specific fracture energy in the radial/longitudinal as well as the tangential/longitudinal testing direction. Furthermore, oven drying at constant high drying temperature along with low EMC did not result in a significant change of specific fracture energy compared with standard drying, but caused greater scattering values in both transverse crack propagation systems.     

Strengthening capacity for agribusiness in agroforestry and natural resources in tertiary agricultural education in Africa: African Network for Agriculture,Agroforestry and Natural Resources Education (ANAFE)

This paper highlights the main achievements of the programme on Strengthening Africa’s Strategic Agricultural Capacity for Impact on Development (SASACID) funded by the Swedish International Development Cooperation Agency (Sida). The programme is implemented by the African Network for Agriculture, Agroforestry and Natural Resources Education (ANAFE) through 16 Pilot Institutions (PIs). It focuses on supporting agribusiness development in tertiary agricultural education and research in Africa. Under the programme, ANAFE is working towards refocusing agricultural learning and development objectives, producing contextualized learning materials, managing risk and uncertainties in agriculture, developing and reviewing curricula, retooling lecturers in pedagogy and strategizing on how best to work more closely with the private sector. The paper build on the final SASACID (2012–2014) report jointly developed through the Results-Based Management logical framework with the 16 SASACID Pilot Institutions (PIs) that met in Nairobi November 11–13, 2014. Results show that even though the PIs are at different levels of achievement over 75 % have achieved 80 % of the expected outputs. Management of scholarships for BSc and MSc students working with the private sector on risk management-related issues is among the outputs achieved by all the Pilot Institutions. Formalizing engagement with private sector through signing of Memoranda of Understanding (MoU) was reported by 25 % of the PIs working in Agribusiness through which students were supported to undertake research or internship within selected private sector firms; about 15 % got employed while others initiated their own businesses. A major output from the programme is the development and sharing of Agribusiness and Risk Management curricula frameworks for all degree levels from Diploma, BSc, MSc and PhD. Four Pilot institutions have signed MoUs with ANAFE to test the Agribusiness curricula at various levels. They are Rongo University College, Taita Taveta University College and Strathmore University (all from Kenya) and (Kenya), Mulungushi University (Zambia). The objective of this paper is to highlight ANAFE’s key achievements in transforming tertiary agricultural education and research in Africa, with specific reference to the SASACID programme. The programme was implemented from 2011 to 2015. Sixteen (16) ANAFE member institutions from 14 countries, competitively selected, implemented the SASACID programme, which focused on Agribusiness and management of risks and uncertainties in agriculture.     

The potential of SilviScan’s X-ray diffractometry method for the rapid assessment of spiral grain in softwood, evaluated by goniometric measurements

The orientation of the tracheid cells with respect to the stem axis (grain angle, spiral grain) exerts a strong influence on numerous material properties. Therefore, several methods have been developed to assess this wood anatomical feature. The current study compares SilviScan spiral grain measurements, which uses X-ray diffractometry, with direct goniometer readings. The correlation between these two methods yielded an r² of 0.874 and a root mean square error of prediction (RMSEP) of 1.21 clearly demonstrating that X-ray diffractometry can provide accurate and rapid information on the grain orientation in Norway spruce (Picea abies (L.) Karst.) or similar structured softwoods.     

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Maximum effective lumen and pit pore sizes of the earlywood and the latewood of never dried loblolly pine sapwood

Summary Measurements of the air pressure required to initially displace a saturating liquid and allow a slow continuous stream of air bubbles to pass through wood cross sections of different thickness, together with the equilibrium surface tension of the saturating liquid, make it possible to calculate the maximum effective opening radii. Previous measurements were made for wood as a whole over complete annual rings. Measurements reported here were made separately for earlywood and latewood. Extrapolating plots of the maximum effective opening radius-cross section thickness, for thicknesses below the maximum fiber length, to zero thickness gave maximum lumen radii of 16 m for the earlywood and 10.3 m for the latewood. The values are only slightly greater than the calculated average values. Extrapolating the plots in the opposite direction to zero opening radius gave approximate maximum lumen or fiber lengths for the earlywood of 6 mm and for the latewood of 5 mm. The maximum effective opening radii for cross sections thicker than the maximum fiber length give maximum effective communicating pore radii. These values continue to decrease, with increasing thickness of the cross sections due to the decreasing probability of the largest openings falling in any one series path through the structures. The maximum effective pit pore radius for passage through fifty pits in series was 0.8 m for the earlywood and 0.28 m for the latewood.Paper No. 3787 of the Journal Series of North Carolina State University Agricultural Experiment Station, Releigh, N. C.     

Digestive enzyme concentrations and activities in healthy pancreatic tissue of horses

OBJECTIVE: To measure concentrations and activities of major digestive enzymes in healthy equine pancreatic tissue. ANIMALS: 7 adult horses with normal pancreatic tissues. PROCEDURES: Small pieces of pancreatic tissue were collected immediately after euthanasia, immersed in liquid nitrogen, and maintained at -80 degrees C until analyzed. Concentrations and activities of amylase, lipase, chymotrypsin, trypsin, and elastase were determined by use of a microtiter technique. Relative pancreatic protein concentrations were determined by use of bovine serum albumin as the standard. Pancreatic DNA was extracted and con-centrations determined by use of the diphenylamine method with calf thymus DNA as the standard. RESULTS: The pancreatic cellular concentration of each enzyme, expressed as units per milligram of DNA, was consistent among horses. Cellular concentration of lipase (1,090.8 +/- 285.3 U/mg of DNA) was highest, followed by amylase (59.5 +/- 9.8 U/mg of DNA). Elastase, trypsin, and chymotrypsin were detected in small concentrations (1.9 +/- 0.6, 3.5 +/- 1.5, and 9.6 +/- 2.9 U/mg of DNA, respectively). Similar results were obtained for specific activities of the enzymes. CONCLUSIONS AND CLINICAL RELEVANCE: Results were unexpected because, under natural conditions, the predominant energy source for horses is carbohydrate. These results may indicate, in part, the reason horses seem to tolerate large amounts of fat added to their diet.     

The co-operative interaction of puroindolines in wheat grain texture may involve the hydrophobic domain

The puroindoline genes are causatively associated with wheat grain hardness, a commercially significant property. The proteins puroindoline (PIN) A and B are both required in their wild-type (WT) to impart soft grain texture, and absence of/mutations in either/both PIN(s) results in hard wheat. However, there is no biochemical clarity yet that explains this interdependence. This work critically analyses the roles of the tryptophan-rich domain (TRD), the little-known hydrophobic domain (HD), and certain other residues, in the physical associations of PINs. Site-directed mutagenesis-PCR was used to delete the TRD or HD and introduce an Arg39Gly substitution in PINA. The PINB-D1c mutant (Leu60Pro) was also investigated. The yeast two-hybrid system was used to assess the protein–protein interactions (PPI) of proteins. The TRD deletion or Arg39Gly substitution in PINA did not adversely affect its PPI, while deletion of HD resulted in a significant reduction. No effect on PPI was observed for Leu60Pro PINB. The results of this expression system strongly suggest that the HD is essential (but not sufficient) in higher-order associations of PINs. We propose a two-event model that explains the co-operative action of the PINs and why mutations outside the TRD may alter grain texture.     

Mercury volatilization from a floodplain soil during a simulated flooding event

Purpose

Middle-European floodplain soils are often contaminated with mercury (Hg) and periodically flooded. In this study, the influence of a flooding event and subsequent dewatering on the volatilization of elemental Hg and methylated species was investigated in a laboratory experiment.

Material and methods

Undisturbed soil cores were taken from a topsoil (12.1?±?0.75 mg kg^?1 Hg) at the Elbe River in Lower Saxony, Germany. Soil columns were incubated at 20 °C with varying soil moisture (water-saturated for 2 weeks, 95 and 90 % water content for 1 week each), and the redox potential (E_H) was recorded. The gaseous Hg that accumulated in the headspace of the flux chamber of the columns was pumped over cooled traps filled with adsorber material and analyzed by gas chromatography/inductively coupled plasma mass spectrometry for the various Hg species.

Results and discussion

The watering of the soil resulted in a rapid decrease in the E_H and the achievement of strongly reducing conditions (E_H??1 Hg at the beginning to 5.78 μg L^?1 Hg at the end of the experiment. Species analyses revealed that exclusively elemental Hg volatilized. The volatilization rate was between 1.73 and 824 ng m^?2 h^?1 Hg, which is consistent with other studies at the Elbe River.

Conclusions

Even when flooded for a longer period of time, floodplain soils should show neither emission of methylated Hg nor exceptionally high volatilization of elemental Hg.     

The nutrient and glycoalkaloid content of a new potato meal

The nutrient and glycoalkaloid content of a new potato meal produced as a by-product of starch manufacture using low temperature dehydration was determined. Comparisons were made between the new potato meal and the previously manufactured meal which was prepared by high temperature dehydration. The glycoalkaloid content of the new potato meal was 15.53mg α-chaconine and 4.75mg α-solanine per 100g meal compared to 15.79mg α-chaconine and 7.83mg α-solanine in the potato meal produced by high temperature dehydration. The new potato meal contained 2% more protein and 1.9, 3.4 and 1.2 times more niacin, riboflavin and thiamin, respectively than the previous by-product. The potassium and phosphorus concentrations were approximately 2.0 and 0.2%, respectively. Other minerals were found in lesser concentrations with the sodium content being only 7.4mg/100g potato meal. A 28g serving would provide approximately 5, 7 and 4% of the RDA for protein, niacin and thiamin, respectively.