bluuebunny/crossref_metadata_2025 huggingface dataset:
Philympics 2021: Prophage Predictions Perplex Programs
Authors: Roach Michael J. , McNair Katelyn , Giles Sarah K , Inglis Laura K , Pargin Evan , Roux Simon , Decewicz Przemysław , Edwards Robert A.
Published: August 2021

Background

Most bacterial genomes contain integrated bacteriophages—prophages—in various states of decay. Many are active and able to excise from the genome and replicate, while others are cryptic prophages, remnants of their former selves. Over the last two decades, many computational tools have been developed to identify the prophage components of bacterial genomes, and it is a particularly active area for the application of machine learning approaches. However, progress is hindered and comparisons thwarted because there are no manually curated bacterial genomes that can be used to test new prophage prediction algorithms.

Methods

We present a library of gold-standard bacterial genome annotations that include manually curated prophage annotations, and a computational framework to compare the predictions from different algorithms. We use this suite to compare all extant stand-alone prophage prediction algorithms to identify their strengths and weaknesses. We provide a FAIR dataset for prophage identification, and demonstrate the accuracy, precision, recall, and f1 score from the analysis of seven different algorithms for the prediction of prophages.

Results

We identified different strengths and weaknesses between the prophage prediction tools. Several tools exhibit exceptional f1 scores, while others have better recall at the expense of more false positives. The tools vary greatly in runtime performance with few exhibiting all desirable qualities for large-scale analyses.

Conclusions

Our library of gold-standard prophage annotations and benchmarking framework provide a valuable resource for exploring strengths and weaknesses of current and future prophage annotation tools. We discuss caveats and concerns in this analysis, how those concerns may be mitigated, and avenues for future improvements. This framework will help developers identify opportunities for improvement and test updates. It will also help users in determining the tools that are best suited for their analysis.
Case Report: Retinal vein occlusion as the first clinical manifestation of systemic lupus erythematosus in a male patient
Authors: Ben Brahim Marwa , Arfa Sondes , Boubaker Fadia , Chelly Jihen , Ammari Wafa , Hammami Sonia , Arbi Fatma , Berriche Olfa
Published: August 2021

Systemic lupus erythematosus (SLE) is a chronic, autoimmune disease characterized by widespread clinical manifestations and immunological disorders. A myriad of ocular manifestations can be seen in patients with SLE. The most vision-threatening complication is vaso-occlusive retinopathy including retinal vein occlusion (RVO). RVO associated with SLE is well described in the literature and its association with antiphospholipid antibodies is recognized. However, RVO as the initial manifestation of SLE is scarcely reported.

Herein, we report the first case of recurrent RVO as the primary manifestation of SLE in a 40-year-old male patient. He had two consecutive episodes of decreased vision. Ophthalmologic examination disclosed a branch retinal vein occlusion the first time and a central retinal vein occlusion the second time. The diagnosis of SLE was established based on clinical and immunological criteria. He was prescribed antiplatelet therapy, hydroxychloroquine at 5.5 mg/kg/day, and intravitreal anti-vascular endothelial growth factor (VEGF) antibodies regimen. He slowly improved under treatment.
Monitoring the Eff ectiveness and Balance of the Organization’s Compliance Control System (Part 1)
Authors: Yakimova Vilena
Published: August 2021

The article is devoted to the study of methodological aspects of assessing compliance control as one of the forms of internal control aimed at preventing violations of legislation in the field of finance, taxes and entrepreneurship. In the course of analyzing the existing methods for assessing the ICS, a theoretical model was formed, including the concept, approaches to organizing, assessing the ICS, a group of qualitative and point-weight methods. The article proposes the author's methodology for testing the internal compliance control system, which has applied significance for monitoring carried out by audit organizations and internal auditors.
Para cantar flamenco hay que ponerse fea
Authors: Pantoja Guerrero Dolores
Published: August 2021

Este es un trabajo bien cimentado. Reposa sobre un amplio trabajo de campo. Dolores Pantoja ha entrevistado a cantaores y cantaoras de edades y procedencias muy variadas. Desde veteranos como Calixto Arias o Pies de Plomo (Manuel Giorgio) hasta Duquende, Mayte Martín o Miguel Poveda. Pero no es esta la principal virtud del libro porque, teniendo en cuenta las entrevistas, la autora construye un cuidado discurso que muestra la potencia del cante para abrir ámbitos de comunicación. Esta capacidad es decisiva para que el flamenco no sea mera reliquia del pasado ni expresión de una cultura local, sino que sintonice con las inquietudes generales que caracterizan a la cultura moderna y se incorpore a ella.
Universal Human Rights? Historical and Contemporary Comments
Authors: Szlachta Bogdan
Published: August 2021

The concept of human rights, supposedly of universal importance, is usually derived from the tradition referred to as “Western”. Although the “classic approaches” – Greek, Roman and Christian, refer to the norms of natural law, making them the basis or limits of the rights of individuals, in modern approaches the relation is reserved, in the manner that rights become primary to norms. Although liberals of the 17th and 18th centuries consider the law of nature as a tool for their protection, starting from the 19th century, the rights (already called human rights) have been increasingly perceived as positive abilities to articulate own, subjective preferences of individuals. This evolution needs to be accounted for in the studies carried out by representatives of various cultures, since the comprehension of an individual (and even a “human person”) as an essentially culturally unconditioned one, is its ineradicable element.
Militarizing Hate, Perpetuating Violence and Rape, and Allowing Human Rights Abuses to Go Unpunished
Authors: Womack Malia Lee
Published: August 2021

The United States does not comply with the International Convention on the Elimination of All Forms of Racial Discrimination (ICERD), which is the United Nations’ core binding anti-racism human rights convention. One hundred and seventy seven states, including the US, have ratified the anti-racism multilateral agreement. The nation entered into the pact in 1994 yet still has not implemented its obligations to the statute. This study focuses on the protections ICERD provides Latino immigrants who are not United States citizens as this group is often ignored in advocacy for implementation strategies. Areas where the United States does not comply with ICERD include discriminatory immigration policies and practices, violent and discriminatory policing, gendered violence, and inequalities in the criminal justice system. It is critical to examine ICERD’s protections for Latino non-citizens because it reveals how the group experiences racism differently than other people because they endure intersectional forms of systematic and institutional discrimination due to their race, ethnicity, citizenship status, gender, and other identity traits. Methodologies used in this study include analysis of ICERD’s monitoring body’s General Recommendations, and the monitoring body’s reports about the United States’ lack of compliance with the statute. These are the most powerful regulatory forces of the treaty due to the monitoring body’s positionality as experts about the pact appointed through the United Nations system.
Analysis of retrieved STRYDE nails
Authors: Hothi Harry , Bergiers Sean , Henckel Johann , Iliadis Alexis D. , Goodier William David , Wright Jonathan , Skinner John , Calder Peter , Hart Alister J.
Published: August 2021

Aims

The aim of this study was to present the first retrieval analysis findings of PRECICE STRYDE intermedullary nails removed from patients, providing useful information in the post-market surveillance of these recently introduced devices.

Methods

We collected ten nails removed from six patients, together with patient clinical data and plain radiograph imaging. We performed macro- and microscopic analysis of all surfaces and graded the presence of corrosion using validated semiquantitative scoring methods. We determined the elemental composition of surface debris using energy dispersive x-ray spectroscopy (EDS) and used metrology analysis to characterize the surface adjacent to the extendable junctions.

Results

All nails were removed at the end of treatment, having achieved their intended lengthening (20 mm to 65 mm) and after regenerate consolidation. All nails had evidence of corrosion localized to the screw holes and the extendable junctions; corrosion was graded as moderate at the junction of one nail and severe at the junctions of five nails. EDS analysis showed surface deposits to be chromium rich. Plain radiographs showed cortical thickening and osteolysis around the junction of six nails, corresponding to the same nails with moderate – severe junction corrosion.

Conclusion

We found, in fully united bones, evidence of cortical thickening and osteolysis that appeared to be associated with corrosion at the extendable junction; when corrosion was present, cortical thickening was adjacent to this junction. Further work, with greater numbers of retrievals, is required to fully understand this association between corrosion and bony changes, and the influencing surgeon, implant, and patient factors involved. Cite this article: Bone Jt Open 2021;2(8):599–610.
Forest Products Utilization Within a Circular Bioeconomy
Authors: Baldwin Richard F.
Published: August 2021

The advent of tall wood structures in North America is heightening a public awareness that forest products, designed for higher and better uses, will lead to enhanced environmental benefits within the Circular Bioeconomy. The application of these newer wood-based processing technologies and their resulting products, in place of completive products such as concrete, steel and other non-wood construction materials, will redefine and expand the advantages that wood has as a construction material.

Further, the growing capability to use small logs, and diverse species, as raw material for the newer generation of forest products will magnify the carbon sequestration benefits from the working forest. A recipe of getting more benefits and improved utilization from the working forest is identified and described, while focusing on the means and methods of obtaining these benefits.
Effect of Knots and Related Grain Deviation on the Rolling Shear in Dimension Lumber Used in Cross-Laminated Timber Transverse Core Layers
Authors: Grandvuinet Thibault , Muszyński Lech
Published: August 2021

Cross-laminated timber (CLT) technology has the potential for utilization of lower grades and underused species of lumber, because the core layers perpendicular to the principal loading direction transfer loads through shear, which is not correlated to the grade of lumber. Currently the product standard specifies the minimum grade requirements for all lumber to be used as CLT laminations. In this study, the effect of the presence of knots in the transverse core layer of CLT billets was examined in matched CLT samples where the heavy presence of knots and the related grain disturbance in the transverse core layer were the only variables compared with knot-free reference. All samples were tested as short beams in three-point bending and all failed in rolling shear in the transverse core layer. The presence of knots had no measurable effect on the shear capacity or stiffness of the tested CLT beam samples.
Drying Urea Formaldehyde Resin–Modified Chinese Fir for Mining Supporting Materials
Authors: Zhao Zhiyun , Li Yun , Li Xianjun , Mou Qunying , Cheng Xiyi , He Xia , Xie Jie , Xiong Xinyang , Quan Peng
Published: August 2021

The drying characteristics of urea formaldehyde (UF) resin–impregnated Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) wood were determined by the 100°C-test method and scanning electron and fluorescence microscopies to predict an optimal drying schedule. Compared with the untreated sample, the UF resin–impregnated Chinese fir wood presented a lower grade of initial checks and a faster initial drying velocity, but a higher grade of internal checks and a slower drying velocity at the later stage. The average drying velocity of the UF resin–impregnated wood was 38.9 percent lower than that of the untreated sample. The predicted drying schedule was applied to the UF resin–impregnated wood and the resulting grades of the drying characteristics were in good agreement with the required national standard values. The resulting dried UF resin–modified composite would become a potential candidate for a shallow depth rock mining supportive system with its stable mechanical performance.
Potential for Using Borates to Mitigate the Risk of Phytophthora ramorum Spread on Douglas-Fir Logs
Authors: Cappellazzi Jed , Morrell Jeffrey J.
Published: August 2021

Phytophthora ramorum is an increasingly important tree pathogen in northern California and southern Oregon. While it has the greatest effect on tanoak, it can infect a wide range of tree species, including Douglas-fir. Oregon has instituted a quarantine area to slow the spread of this pathogen, and there are concerns that further restrictions may be imposed on log movement, including those of Douglas-fir. The potential for using boron as a log treatment to limit P. ramorum was evaluated. While boron either alone or in a glycol solution was capable of moving into the bark, there was no evidence that it could move further into the sapwood. The results suggest that bark removal would be necessary for the use of boron as a mitigation agent for the spread of P. ramorum.
Study on the Price Fluctuation and Dynamic Relationship between Log and Sawn Timber
Authors: Zhao Rong , Diao Gang , Chen Shaozhi
Published: August 2021

The rapid economic and social growth of China has significantly increased its timber demand, resulting in a heavy reliance on foreign timber supply. Thus, price fluctuation in the international market poses a great risk to domestic timber production and processing enterprises. This study analyzed the dynamic conduction relationship between domestic and international logs and sawn timber markets and how to reduce risks by adjusting the structure of imported products' portfolios. In this article, the multivariate generalized autoregressive conditional heteroskedasticity model is applied to analyze the relationship between domestic and import prices of logs and sawn timber. The study found that among four markets, except one where the short-term spillover effect between domestic logs and sawn timber is large with statistical significance, spillover effects are small. In the long run, there are significant spillover effects between the four markets. Thus, changes in the international log market are very easy to transfer to the domestic log market through trade and then to the downstream domestic and international sawn timber markets. Therefore, in order to ensure timber security in China, this study uses the theory of portfolios to calculate product proportion with minimum risks. The proportion of portfolios indicates that, even though Chinese companies prefer logs, they have to import a great amount of sawn timber due to restrictions on log exports from sourcing countries, which increases the risk of timber supply.
Thermal Conductivity of Low-Density Wood Composite Mats
Authors: Nakaya Takashi , Yamasaki Mariko , Fukuta Satoshi , Matsuda Yuki , Sasaki Yasutoshi
Published: August 2021

In order to effectively use the waste produced during lumber sawing, the thermal conductivities of wood composite mats shaped by thermoforming and composed of wood shavings, kenaf fibers, and binders were examined by assuming a one-dimensional heat transfer process that could be described by the sum of its heat conduction and radiation components. To improve the heat-insulating properties of the mats, various types of auxiliary raw materials were examined. Mat density depended on the volumetric ratio of the air layer inside the mat to the fiber layer. In the low-density region, increasing the mat density decreased the magnitude of the radiation component and thus the thermal conductivity of the mat, whereas in the high-density region, increasing the mat density increased the value of the conduction component, which in turn enhanced the thermal conductivity of the mat. The minimum value of the thermal conductivity obtained under all experimental conditions is 0.062 W/m·K. Thus, it is difficult to decrease the thermal conductivity of the mat below 0.060 W/m·K by varying its density and mixing ratio. The utilized model predicted that mat thermal conductivity would be less than 0.060 W/m·K if the fibers with a density similar to that of Japanese cedar wood (0.40 g/cm3) were used.
Timber Losses from West Fork Complex Fire in Southwest Colorado
Authors: Cyphers Laren , Mackes Kurt , Duda Kevin
Published: August 2021

This article provides an assessment of fire effects on timber burned in the West Fork Complex fire area, located in the San Juan Mountains of Colorado. The West Fork Complex fire burned 109,615 acres in 2013, and suppression costs alone totaled $33.2 million. Much of the fire occurred in spruce–fir forests that were previously affected by spruce beetle (Dendroctonus rufipennis). Several timber sales were actively occurring within the fire footprint, and more were anticipated to begin in subsequent years. To provide a more accurate valuation estimate, base log stumpage data from 2003 through 2017 were included in this study to show high degrees of variation over time. With base log stumpage values determined, estimates of total hundred cubic feet of each significant species were calculated using geospatial and forest inventory analysis data. This study determined the timber value loss resulting from the coupled disturbance events of the spruce beetle epidemic and a wildland fire to be $19,083,102. This estimate will allow for a more accurate valuation of the actual damage resulting from the West Fork Complex fire. This study may also be useful in supporting the literary basis for salvage and fuels management after a beetle outbreak to prevent such timber value losses from occurring.
Analysis and Optimization of the Tensioning Effect on a Wood-Cutting Circular Saw Blade Tensioned by Multispot Pressure
Authors: Li Bo , Zhang Zhankuan
Published: August 2021

In recent years, a multispot pressure tensioning process appeared in the field of circular saw blade manufacturing. Due to the insufficient understanding about the formation and evolution of the tensioning effect of this process, this study aimed to analyze and optimize the tensioning effect on a circular saw blade tensioned by multispot pressure. It could provide a theoretical basis and key technical parameters for regulating and controlling the tensioning effect of this process. In this article, the natural frequency and the tensioning stress field of a circular saw blade tensioned by multispot pressure were calculated by ABAQUS software. The simulated tensioning stress field was in agreement with the experimental results, which confirmed the accuracy of the simulation model. The influence of process parameters on the natural frequency and tangential tensile stress in the edge of the circular saw blade was examined and compared based on the orthogonal method. Simulation results show that the parameters of the multispot pressure tensioning process have different degrees of influence on the tensioning effect of a circular saw blade. Considering the natural frequency and tangential tensile stress in the edge of a circular saw blade synthetically, optimal process parameters for multispot pressure tensioning were obtained.
Using Acoustic Emission Technique to Detect Termite Activities in Wood: Laboratory Experiment
Authors: El-Hadad Ahmed , Brodie Graham Ian
Published: August 2021

This experiment studied and analyzed termite activities in wooden blocks. The purpose of the study was to develop and test a strategy for isolating termite acoustic emissions (AE) from background noise. This task is not trivial, and therefore the achievement of a clean signal that can be directly associated with termite activities is a good outcome. It is an important step toward achieving an accurate, nondestructive system to detect termite activities in wood. The wooden blocks were immersed in jars that were filled with termites to expose the blocks to termite infestation. The termites' AE, due to their activity in the wood, was recorded using microphones that were fitted in the center of each wooden block. The Cool Edit Pro 2.1 (Syntrillium Software Corporation) sound recording application was used to filter the recorded AE signals. The filtered AE signals were then analyzed using the Matlab application. The wooden blocks experiment showed that termite activities in the wood could be detected using AE recording. Termite activities are clear and detectable in the 4.5- to 5-kHz range of frequencies. Results could also assist in defining the termites' AE signature, to some extent, by analyzing the generated sound due to termite activities in the wood. A clean termite-related AE was successfully extracted from the general AE in the wooden blocks using Matlab R2015a tools.
Effects of Premixing Wood Flour with Compatibilizer with Different Characteristics on the Physical and Mechanical Properties of Wood/Plastic Composites
Authors: Murayama Kazushige , Kojima Yoichi , Kobori Hikaru , Aoki Kenji , Suzuki Shigehiko , Ito Hirokazu , Ogoe Shinji , Okamoto Masaki , Ema Tomoyuki
Published: August 2021

The addition of maleic anhydride (MA)-modified polypropylene (MAPP) as a compatibilizer increases mechanical and physical properties of wood/plastic composites (WPCs). It is thought that MA graft ratio (Gr), molecular weight (weight-average molecular weight [Mw]), and mixing methods of MAPP affect physical and mechanical properties of WPCs. However, evaluation, especially for mixing order, is not enough. The objective of this study was to investigate the effect of Gr and Mw of MAPP and its mixing methods on the mechanical and physical properties of WPCs. Two types of mixing methods were used: mixing the MAPP with the filler using a Henschel mixer before kneading with PP (premixing method) and mixing all of the materials at one time (one-step mixing method). The WPCs made with the premixing method had lower shear viscosity and higher flexural modulus than those made with the one-step mixing method. The particle size, moisture content, and surface morphology of fillers are thought to be more important in determining the shear viscosity of WPCs than the MAPP itself. The highest tensile, impact, and flexural strengths of WPCs were obtained in the WPC with premixing with low-Gr and high-Mw MAPP. It may be due to the effective reaction of the wood flour with MAPP and higher entanglement between the MAPP and PP. These results suggest that the premixing method could improve productivity and mechanical properties of WPCs.
Processing Variable Optimization of Plywood Hot Pressed with Ba2+-Modified Phenol-Formaldehyde Resin by a Response Surface Method
Authors: Chen Zhangmin , Chen Yuhe , Cai Hanjiang , Han Jian
Published: August 2021

Ba(OH)2 was added in the synthesis of phenol-formaldehyde resin to realize a low-temperature and fast-bonding process for plywood production. Plywood bonding was investigated by studying a number of parameters, such as the glue spread, the amount of curing agent, and the temperature and duration of the hot-pressing process. The plywood bonding strength was characterized by the shear strength of the adhesive layer, and a mathematical model describing the process and the response was developed using a central composite design and response surface methods. The variance analysis revealed that the newly developed model was reliable, with a high signal-to-noise ratio. All the factors and their interactions were analyzed to optimize the bonding process. Thus, seven optimized processes were obtained from the model, and the optimal process conditions were revealed (glue spread: 277.8 g/m2; amount of curing agent: 3.5%; hot-pressing temperature: 108°C; and hot-pressing duration: 34.99 s/mm). The results from repeated average shear strength experiments of five veneer testing samples (1.64 MPa) verified the reliability of the optimized technics.
Supply of Woody Residuals in the Northwest Region of Arkansas (2017) for Energy Production
Authors: Sherman Gabrielle , Pelkki Matthew
Published: August 2021

Northwest Arkansas was identified as a region of interest for the production of wood-fueled electrical power due to its pervasive timber industry and need for cost-effective forest management. It is believed that by utilizing wood residuals produced from sawmill operations, a stable source of revenue could be provided to local wood processing businesses while simultaneously providing clean energy to the region. In order to evaluate the amount of available material available for energy production, all known mills were surveyed within the 16-county study region for their annual production of sawdust, slabs, and other residual products. Data on production of residuals were developed into supply curves and equations. Supply was found to be inelastic for both hardwood and softwood mill residuals in the region. Given that residual production is a secondary effect of timber processing, supply inelasticity is expected. Increasing the quantity of mill residuals in the region will likely be accompanied by greater-than-proportional price increases. We determined that 96,744 tons of ovendried material would be available annually for purchases at a delivered price of $38 per ton. With this quantity, the region could be expected to support a small combined heat and power energy facility with output between 5 and 10 MW.
New Pretreatment Methods for Visible–Near-Infrared Calibration Modeling of Air-Dry Density of Ulmus pumila Wood
Authors: Li Ying , Via Brian K. , Cheng Qingzheng , Zhao Jinghan , Li Yaoxiang
Published: August 2021

Due to the multidimensional complexity and redundancy between wavelengths in the visible and near infrared (Vis-NIR) region, the speed and accuracy of data analysis can be affected. This study aims to investigate the feasibility of simplifying high dimensional data based on transformation of the spectra and local correlation maximization (LCM). These two methods will be applied to determine the prediction accuracy of air-dry density of Ulmus pumila wood. In this study, the reflectance spectra (Refl.) were subjected to the reciprocal (1/Refl.) and logarithm reflectance to improve the spectra signal for prediction. LCM was developed for selecting spectral sensitive regions that were important in the prediction of density. A local correlation coefficient (r) criterion was developed such that if the r ≥ 0.75 (between wavelength and density), then partial least squares and support vector machine (SVM) were employed as the prediction method. Likewise, 2D correlation spectroscopy plots were used to further reduce the data matrix by removing redundant wavelengths. The results showed that (1) although the sensitive region of density was different, the region of r ≥ 0.80 was mainly in the Vis and NIR spectral region. Additionally, the performance of models developed from the sensitive region was better than that of data used from the less-sensitive region. (2) The SVM model was optimized by a genetic algorithm based on the log (1/Refl.) of the sensitive region. In conclusion, it was found that the spectral transformation presented better density estimation results ( = 0.909, root mean square error of calibration = 0.014) than when less sensitive wavelengths were used in the data matrix.
Finite Element Resonance Analysis of the Complex Structure of a Crosscut Saw Machine
Authors: Chen Wei-long , Chao Fang-lin , Lin Yu-hui
Published: August 2021

A crosscut saw machine must be tuned to eliminate abnormal sawing marks or skewing during rapid wood processing. Once a wooden board is placed in the feed port, it is clamped and stabilized by a roller. However, the vibration amplification of the structure still causes the relative position of the blade to change and leads to the problem of saw marks on the wood surface. This article optimizes a saw machine by modal analysis based on the finite element method. The redesigned machine was compared to the original for natural frequency and mode shape. The analysis results revealed that at 31.43 Hz, stress reached the maximum value of 383.24 MPa on the frame of an alternating current motor. The mode shape showed significant deformation of the roller frame. By applying ribs on the chassis frame, vertical bending and torsion were reduced. The frequency of the sixth mode of the original machine was 43.9 Hz, which increased to 52.9 Hz after the redesign. The results showed that this was due to the addition of the ribs. A clamping roller was able to mitigate the vibration through the +y and z directions. The natural frequency of the modality was significantly improved through rib-enforced design. The structure of the improved design exhibited improvement compared to the original machine.
Comparative Performance of Modified Solid and Composite Wood Samples in Standard Tests
Authors: Rose Robert , Leavengood Scott , Morrell Jeffrey J.
Published: August 2021

The properties of several modified wood products were evaluated using North American standards to provide comparative data for architects seeking to use these materials. In general, modified wood products had lower moisture uptakes and less shrinkage than unmodified products. Acetylated materials were highly resistant to fungal decay, whereas thermally modified and furfurylated materials were classified as decay resistant. All materials were susceptible to mold, although the nonacetylated moisture-resistant medium-density fiberboard was most susceptible. Thermally modified and furfurylated materials were similar in mold susceptibility to untreated radiata pine sapwood, whereas acetylated materials appeared to be more mold resistant.
Exploring the Sources of Labor Productivity Growth and Convergence among State-Owned Forestry Enterprises in Northeast China
Authors: Ning Youliang , Yu Jinna , Zhang Han , Ning Zekui , Liu Zhen
Published: August 2021

The state-owned forestry enterprises (SOFEs) are important producers of forest products in China, and their competitiveness depends largely on their labor productivity (LP). This article is the first to investigate the sources of LP growth and the convergence patterns of SOFEs in northeast China. Based on panel data from 87 SOFEs in northeast China from 2006 to 2018, this article has used the Cobb-Douglas production function to analyze the sources of LP growth, using three convergent methods to explore convergence patterns. The results show that there is a positive correlation between LP and an SOFE's ability to compete, and that both total factor productivity and capital-to-labor ratio significantly contribute to LP growth in all SOFEs of northeast China; however, the role of the quantity of labor was negative. On the whole, all SOFEs did not have σ-convergence in LP growth, but an absolute and a conditional β-convergence. Although the LP divergence between SOFEs in northeast China has not been narrowed, there has been a “catch-up effect” in LP growth. These results can help people understand the laws pertaining to LP growth among forest enterprises and also how they may reduce production costs, improving market competitiveness among forest products.
The Effect of Multiple Knots in Close Proximity on Southern Pine Lumber Properties
Authors: Barbosa Marcela Cordeiro , Street Jason , Owens Frank C. , Shmulsky Rubin
Published: August 2021

Lumber grade rules address well-spaced single-knot and combination-knot sizes. Information is lacking, however, with respect to multiple knots in close proximity. The term “well-spaced” appears to lack quantitation. This research investigates the effect that knots in close proximity (not necessarily combination knots) have on the strength properties of southern yellow pine (SYP; Pinus spp.) lumber. This study attempts to use a statistical model to determine the modulus of rupture (MOR) for SYP having multiple knots in close proximity using variables including the knot diameter (KD), amount of clear wood (CW) present, knot area (KA), and modulus of elasticity (MOE) of the lumber. This study investigated specimens of 2 by 4-inch SYP dimensional lumber exhibiting multiple knots in close proximity. The basic density (D) was determined by dividing the entire specimen weight by its volume. Third-point bending tests were used in flatwise orientation to quantify the MOR and MOE. There were significant correlations among all parameters analyzed. Multiple regression analysis with one dependent variable, MOR, and three independent variables, KD, MOE, and D, resulted in a coefficient of determination value (r2) of 0.702. When using only the MOE to predict MOR, an r2 value of 0.564 was found.
Performance of Internal Remedial Treatments on Douglas-Fir Poles: A Large-Scale Field Trial
Authors: Konkler Matthew J. , Cappellazzi Jed , Love Connie S. , Freitag Camille , Morrell Jeffrey J.
Published: August 2021

Internal decay is a common problem in poles or timbers of thin sapwood species. Several internal treatments have been developed to arrest this attack, and these systems are widely used in North America. Although these treatments have been evaluated in numerous independent field trials, there is no single test of all treatments. The objective of this study was to assess the chemical distribution and fungal colonization in Douglas-fir poles treated with each of 13 different internal remedial treatments over a 10-year period. Metam sodium treatments provided the shortest protective period, with little evidence of residual chemical 3 years after treatment. Methylisothiocyanate (MITC) in pure form provided a very high initial flush of active ingredient and a longer protective period extending from 5 to 8 years after treatment. Dazomet, which must decompose to produce MITC, took slightly longer to reach effective levels, but was still present at effective levels 10 years after treatment. Chloropicrin, which has strong interactions with wood, was associated with the highest chemical levels after 10 years. Borates took longer to reach effective levels in the poles and their protective zone was narrower than the fumigants, but boron was still present at effective levels 10 years after application. The results illustrate the different properties provided by each treatment, but also show that all tested remedial treatments were effective within certain limitations.
Frequency Domain Identification of Acoustic Emission Events of Wood Fracture and Variable Moisture Content
Authors: Li Xinci , Li Ming , Ju Shuang
Published: August 2021

The effect of moisture content on acoustic emission (AE) during wood damage was studied and the degree of damage was evaluated accordingly. In this article, the Pinus massoniana test-pieces of three different moisture content states, which are ovendried, air-dried, and water-saturated, were used to study the AE frequency characteristics of wood during bending failure. The original AE signal was subjected to wavelet denoising, and the denoised AE signal was classified into DAE (deformation AE) and FAE (fracture AE) according to the frequency distribution characteristics. Then, the instantaneous frequency of the AE signal was obtained by Hilbert transform, and the density of the two types of AE events was separately counted to evaluate the damage degree of the wood. The test results show that the AE signal in the process of wood damage and fracture was composed of two frequency components. The DAE signal frequency was concentrated at 30 to 60 kHz, the FAE signal was concentrated at 160 to 170 kHz, and the moisture content had no significant effect on the frequency distribution of AE events. In addition, the moisture content caused a change in the fracture toughness of the wood, so that the AE event density characteristics of the three damage processes were different. In particular, the ovendried test-piece showed obvious brittle fracture, and the AE event density level was slightly changed. Studies have shown that the change of AE event density based on instantaneous frequency can objectively evaluate and predict the degree of wood damage and fracture.
Effect of Elevated Temperature Exposures on Shear Properties of Sheathing Panels
Authors: Soti Rajendra , Knight Cody , Mageshwar Shanmathi , Valluri Srikar D. , Sinha Arijit
Published: August 2021

Structural wall sheathing such as oriented strand board (OSB) and plywood have been heavily used in residential and commercial timber frame construction. The response of these wood-based composites under elevated temperatures between 100°C and 200°C (herein referred to as elevated temperatures) and exposure time needs to be characterized to assess residual strength of the materials in the existing structures. The main objective of this work is to study the effect of temperature and exposure time on shear strength and shear modulus of plywood and OSB. A total of 110 test specimens was tested in shear after exposure to five different temperatures and two exposure durations, followed by cooling to ambient temperature. The results indicated that the plywood and OSB behaved differently after exposure to elevated temperatures and exposure duration. Plywood showed a consistent degradation of shear strength with elevated temperature and time, while OSB did not exhibit a clear picture of thermal degradation. The results further indicated that the shear modulus of plywood and OSB remained unaffected after exposure to elevated temperatures.
Unit Costs and Trends within Louisiana's Logging Contract Rate
Authors: McConnell T. Eric
Published: August 2021

Quarterly unit costs for a hypothetical logging firm were determined from the logging contract rate for Louisiana spanning the years 1992 to 2018. Machine rate methods were employed to disaggregate the contract rate into five cost centers: felling, skidding, loading, trucking, and tertiary (e.g., trucks, bulldozer, chainsaw). Risk was explained by the quarterly interest rate on a 30-year mortgage, and income taxes were estimated as a fixed percentage of gross income. The real logging contract rate averaged US$19.08 per ton (2018 constant dollars), and it has risen at an annual rate of 1.03 percent above that of inflation for roundwood. Trucking was the firm's highest cost activity followed by skidding, loading, felling, and tertiary. Rates of cost change followed the order of tertiary, trucking, loading, felling, and skidding. The firm faced financial hardship sporadically from 1992 through 2001, but profits were consistently returned from the second quarter of 2000 through the fourth quarter of 2006 (2000Q2 through 2006Q4). Since then, company earnings have fluctuated between profit (n = 25 quarters) and loss (n = 23 quarters). Losses were consistently generated from 2010Q4 through 2013Q2, and all of 2014, as well as in the final three quarters of 2018. Simulation of the contract rate and firm unit costs as stochastic processes utilizing a uniform distribution indicated a 0.48 probability of at least breaking even, but that increased to 0.69 when employing a normal distribution.
Variations in the Anatomical Characteristics of Bambusa pervariabilis Culms with Age and Height
Authors: Xiang Elin , Guo Yihan , Yang Shumin , Liu Xinge , Tian Genlin , Ma Jianfeng , Shang Lili
Published: August 2021

The anatomical characteristics of culms in Bambusa pervariabilis bamboo at different ages and heights were investigated by microscopy and image analysis. Among the two vascular bundle types found in culms, the broken-waist type was considered typical, with the following measurements: average proportion of fibrous tissue, 41.53 percent; length, 1.75 mm; slenderness ratio, 117; and Runkel ratio, 4.00. These values were close to those of the moso bamboo (Phyllostachys edulis), which is commercially relevant in China. Age and height significantly influenced the anatomical characteristics of B. pervariabilis: with an increase in age, both the length and double-wall thickness of the fiber gradually increased, whereas its lumen diameter decreased. The width of vascular bundles and the length, width, double-wall thickness, and lumen diameter of fiber markedly decreased from the bottom to the top. Therefore, B. pervariabilis is an ideal raw material for pulping and papermaking, and its performance is close to that of moso bamboo.
An Educational Needs Assessment of Workforce Supply and Readiness in Maine's Forest Products Industry
Authors: Bernsen Nicole R. , Crandall Mindy S. , Leahy Jessica E.
Published: August 2021

A combination of youth out-migration and lack of in-migration have led to an aging workforce and population decline in Maine, whereas simultaneous declines in pulp and paper demand and biomass utilization have had negative impacts on the perceived future of the once-dominant forest products industry. These changes may increase uncertainty among employers as to the availability and training of the next generation of forest industry workers. This study reports our findings from an analysis of workforce supply and readiness in Maine's forest products industry. To estimate possible gaps in skills and work culture, we administered a survey to current forestry students and employers in the forest products industry. Skills were assessed in three domains: soft skills, knowledge skills, and technical skills. Our gap analysis focused on the difference between the stated importance of skills to employers and the current level of skill knowledge in the workforce across all three domains. Employers identified dealing with change, motivating personnel, negotiating contracts, problem solving, and financial analysis as the top educational needs. In addition, we assessed the willingness of students to accept the culture of work within the forest products industry. Despite the anecdotes shared by employers, we did not find significant evidence of a work culture mismatch between current students and their potential future employers. We recommend that gaps related to regulations, certification standards, or log scaling be addressed through workshops or on-the-job training, whereas areas such as customer relations, marketing, or problem solving could be emphasized in academic curriculum.
Increasing Cold Tack of Polymeric Methylene Diphenyl Diisocyanate Resin with Partial Soy Flour Substitution
Authors: Asafu-Adjaye Osei , Via Brian , Banerjee Sujit
Published: August 2021

Partial substitution of polymeric methylene diphenyl diisocyanate resin with soy flour increases the cold tack of the resin to the level achieved by urea formaldehyde resin. The tack can be fine-tuned by adjusting the amount of soy flour added. The increase in tack is caused by the reaction of the isocyanate resin with the water contained in soy flour, as well as with hydroxyl and other groups present in soy flour components. The higher cold tack should increase the stability of pre-press mats, especially in particleboard manufacturing.
Nondestructive Evaluation of 2 by 8 and 2 by 10 Southern Pine Dimensional Lumber
Authors: França Frederico José Nistal , França Tamara Suely Filgueira Amorim , Seale R. Daniel , Shmulsky Rubin
Published: August 2021

This study investigated the use of two nondestructive testing (NDT) methods to evaluate the mechanical properties of No. 2 grade: 2 by 8 and 2 by 10 southern pine lumber. The dynamic modulus of elasticity (dMOE) of each specimen was evaluated nondestructively by using longitudinal vibration and transverse vibration in edgewise and flatwise directions. After the NDT evaluation, the specimens were destructively tested and correlations between static bending MOE with modulus of rupture (MOR) and dMOE were developed. The overall MOE values were 11.14 and 10.96 GPa for 2 by 8 and 2 by 10, respectively. For MOR, the overall value for 2 by 8 was 42.59 MPa, and for 2 by 10 was 43.05 MPa. As expected, results showed statistically significant correlations between static MOE and dMOE (with r ranging from 0.87 to 0.96 for both sizes tested). Also as expected, weaker correlations were found between MOR and the dMOE values (with r ranging from 0.42 to 0.57 for both sizes tested). The lower correlations are largely explained by the difference between the NDT tools analyzing each specimen's global stiffness versus MOR, which is influenced heavily by localized characteristics. Perhaps this finding occurred because larger strength-reducing characteristics are permitted in larger section pieces (2 by 8 vs. 2 by 10) and thus they have opportunity for greater variability. The continuation of studies to develop more reliable NDT is crucial to improve the evaluation of mechanical properties of southern pine lumber and is beneficial to the southern pine timber industry.
Dynamic Spillover between the Chinese and International Wastepaper Markets: Analysis of the Impact from China's Newly Implemented Wastepaper Policies
Authors: Shang Di , Li Huajing , Yao Jun
Published: August 2021

As China is the largest importer of wastepaper in the world and is highly dependent on the international market, the relationship between the Chinese and international wastepaper markets affects the stability of both markets. The purpose of this study was to investigate the impact of China's newly implemented wastepaper polices on the degree of integration between the Chinese and international wastepaper markets and analyze the dynamics of the relationship between the two markets over time. We developed both the static and dynamic total spillover indices to analyze the degree of integration in average and in time-varying perspectives and performed E-Divisive with Medians (EDM) on the dynamic total spillover index to evaluate the impacts of the new policies. The results revealed that the Chinese and international wastepaper markets were integrated. The calculated dynamic total spillover index varied widely during the studied period and presented an overall declining trend, indicating that these policies have disrupted the integration relationship between the two markets. The results of EDM detected structural breaks in the dynamic spillover index due to the new policies, further confirming and describing the negative impacts of the new policies on the integration relationship between the two markets. Since mutual dependence exists between the Chinese and international wastepaper markets, the interventions on the integration relationship have led to dramatic fluctuations and expanding price differences between the two markets, imposing risks and uncertainties on the stable development of China's paper industry and the global recycling industry.
Process Parameter Investigations on Poplar Wooden Brick for Indoor Partition Wall
Authors: Wang Meng , Dong Rongdan , Lu Zeguang , Jia Wanda
Published: August 2021

Green building materials made from waste wood fiber have attracted worldwide attention. Poplar wood fiber can be molded into indoor partition wall brick with calcium hydroxide. The best process parameters are studied by single and multifactor methods. Compressive strength increases with the decreasing poplar wood fiber content and increasing calcium hydroxide content. The best process is 310 g of poplar wood fiber, 1,849 g of calcium hydroxide, and 10 minutes of cold press time. The mass proportion of poplar wood fiber and calcium hydroxide is 14:86. Compressive strength is affected extremely significantly by the interaction of poplar wood fiber mass, calcium hydroxide mass, and cold press time. It is affected significantly by the interaction between the calcium hydroxide mass and cold press time. The results are important to effectively use poplar wood fiber.