Canadian Wood Council

The R language is widely used for data analysis. However, it does not allow for complex object-oriented implementation and it tends to be slower than other languages such as Java, C and C++. Consequently, it can be more computationally efficient to run native Java code in R. To do this, there exist at least two approaches. One is based on the Java Native Interface (JNI) and it has been successfully implemented in the rJava package. An alternative approach consists of running a local server in Java and linking it to an R environment through a socket connection. This alternative approach has been implemented in an R package called J4R. This article shows how this approach makes it possible to simplify the calls to Java methods and to integrate the R vectorization. The downside is a loss of performance. However, if the vectorization is used in conjunction with multithreading, this loss of performance can be compensated for.

Consider for a moment the rate of advancement in the scientific understanding of DNA. It is formidable; from Fredrich Miescher’s nuclein extraction in the 1860s to Rosalind Franklin’s double helix X-ray in the 1950s to revolutionary next-generation sequencing in the late 2000s. Now consider the scientific paper, the medium used to describe and publish these advances. How is the scientific paper advancing to meet the needs of those who generate and use scientific information? We review four essential qualities for the scientific paper of the future: ( i) a robust source of trustworthy information that remains peer reviewed and is ( ii) communicated to diverse users in diverse ways, ( iii) open access, and ( iv) has a measurable impact beyond Impact Factor. Since its inception, scientific literature has proliferated. We discuss the continuation and expansion of practices already in place including: freely accessible data and analytical code, living research and reviews, changes to peer review to improve representation of under-represented groups, plain language summaries, preprint servers, evidence-informed decision-making, and altmetrics.

Dans la version anglaise de ce texte paru pour la première fois en 2008, l’auteure explique le sens que prend pour elle le travail d’écriture dans la lutte politique des femmes autochtones. À travers une considération du travail de différentes auteures et militantes autochtones, elle y théorise le rapport de nécessité entre la voix de l’écrivaine et l’indépendance politique. Son texte s’avère important pour comprendre l’épistémologie autochtone, la relation entre la vie et l’écriture, de même que la perspective indigène sur la critique littéraire. De plus, l’auteure synthétise bien la perspective qu’elle a développée et portée dans l’ensemble de son travail intellectuel et militant, perspective qui reste peu connue à ce jour auprès du public francophone.

Most models of modulus of elasticity (MOE) and modulus of rupture (MOR) use classical dendrometric variables and do not use crown characteristics that are known to influence wood formation and properties. The objective of this study was to evaluate the benefit of including crown variables in black spruce MOE and MOR models. Values of MOE and MOR were measured on 99 boards from 21 black spruce trees located in nine stands in the Lac-Saint-Jean region of Québec (Canada). Site, tree and crown variables (crown surface area, crown length, branch basal area) were measured. Stand age and basal area were found to be positively related to MOE and MOR. Stem DBH and crown length were negatively related to MOE and MOR. When including crown variables, Akaike's Information Criterion was stable while the R2 increased slightly (+ 2.7% for MOE and + 1% for MOR). The small benefit in model performance associated with the inclusion of crown variables in MOE and MOR models suggests that models without crown variables could be used for industrial purposes without much loss in performance.

Summary This paper shows that mud-filtrate invasion prior to drillstem testing in low-permeability gas formations can cause significant reduction of gas flow rate observed during the test. In addition, apparent gas permeabilities determined from test data can be much lower than the true values. These conclusions are supported by simulator results and field data. Introduction Interpretation of drillstem tests (DST's) in low-permeability gas formations is difficult. and this difficulty leads to uncertainty in identifying formations that, when stimulated, could become commercial completions. Operators have tong suspected that mud-filtrate invasion into these low-permeability formations could contribute to these uncertainties because of significant alterations in relative permeability and capillary pressure. These uncertainties led us to a study of the effects of mud-filtrate invasion on response in a DST; this paper reports the results of that study. In this investigation, we used a two-phase, two-dimensional, fully implicit reservoir simulator to model DST's. The input data for the simulator were obtained from special core analyses. openhole tops, and DST's from the Falher sandstone in western Canada. Model Description The two-dimensional, two-phase model used in this study has been described previously in the literature. The model simulates the flow of gas and water in the formation using a simultaneous determination of saturations and pressures from finite-difference approximations of the gas and water flow equations. Capillary pressure and relative permeability data are input into the model; the model is therefore capable of simulating imbibition, water blocking, and cleanup effects. These effects are potentially important in DST performance. To simulate a DST, uniform initial pressures and saturations were established in the model for all reservoir cells. To model the imbibition of filtrate into the formation prior to the DST, the pressure in the wellbore was set equal to (and maintained at) the hydrostatic mud pressure, and the water (filtrate) saturation was maintained at 100%. Water saturations and pressures around the wellbore increased during the imbibition period as filtrate moved into the reservoir. To model a mud filter cake, the permeabilities in the formation adjacent to the wellbore were reduced. Following the imbibition period, a flow period was simulated. During the flow period, the pressure in the wellbore was maintained at a fixed pressure and the wellbore volume was set equal to the value of a typical drillpipe open to flow. Following the flow period, a pressure buildup test was simulated, with the wellbore volume set equal to a typical volume below the shut-in valve in a DST tool assembly . JPT P. 299^

Heat conduction scaling relations are given, particularly some relating time and dimension, and empirical findings are used to permit their extension to fire resistance problems, including those relating to concrete-encased steel columns. The merit of scaling, apart from its simplicity, is that it does not require a knowledge of the thermal properties of the materials involved and that it takes into account variation of thermal properties with temperature and many of the effects of moisture.