End Splitting Research Articles

The effect of pin distractor assistance on the reduction of fibular fractures in the treatment of ankle fracture: A retrospective case-control study.

This study will evaluate the therapeutic effect of pin distractor assisted reduction of fibular fracture on ankle fracture. A retrospective analysis was performed on 98 patients diagnosed as ankle fracture or pilon fracture. These patients were all combined with fibular fracture. Retrospective analysis included 48 patients in the experimental group (distractor assisted reduction) and 48 patients in the control group (without pin distractor). The statistical indexes include: the time spent in fracture reduction and fixation, the length of surgical incision, the operative blood loss of fracture operation, the incidence of incision skin necrosis, the incidence of fracture end splitting during reduction, the quality of fracture reduction, the time of fracture healing, infection rate, and The American Orthopedic Foot and Ankle Society score at the last follow-up. There were statistical differences between the 2 groups in the time spent in the reduction and fixation of fractures, the incidence of fracture end splitting during reduction, the quality of anatomical reduction of fractures, and the healing time of fractures. The experimental group was better than the control group. In addition, for patients with long spiral fracture, comminuted fracture, osteoporotic fracture and preoperative delay time for operation more than 2 weeks, the time spent in the reduction and fixation of fracture, the operative blood loss of fracture operation, the incidence of fracture end splitting during reduction, the quality of anatomical reduction of fracture, and the healing time of fracture in the experimental group are also better than those in the control group. The pin distractor assisted reduction of fibular fracture has the advantages of simple operation, less trauma, short operation time, less operative blood loss, and fewer complications. It is especially suitable for patients with long spiral fibular fracture, comminuted fracture, osteoporotic fracture, and long preoperative delay time in ankle fracture.

Gradient ceramic structures via multi-material direct ink writing

Dense boron carbide-silicon carbide specimens with composition tailored at the mesoscale were produced by direct ink write additive manufacturing in three configurations: I, 2 % and II, 10 % compositional layer-to-layer steps, and III, homogeneous composition throughout. Flexural strength, indicative of tensile failure, is the highest for the Type-II design (366 MPa) due to its compressive residual stress state in the surface layers. Analysis of thermally-induced residual stresses predicts the ranking of the flexural strengths obtained for Type-II (highest), Type-I (intermediate), and Type-III (lowest) specimens. Compressive strength is load-orientation independent, highly strain-rate dependent, and reduced for specimens with thermal residual stress. Mechanical tests were performed in cube and dumbbell geometries. Dumbbell geometry compression specimens have a compressive strength that is 68 % (quasistatic) and 86 % (dynamic) higher than that of cube geometry and show a greater strain rate dependence. The rate dependency is attributed to the competition between crack propagation and loading velocities. Type-I dumbbells show the highest mean compressive strength of 3.96 GPa (quasi-static) and 5.11 GPa (dynamic). The failure mode evolves from mixed intergranular/transgranular at low strain rates to transgranular at high strain rates. High-speed video analysis indicates that dumbbell geometry specimens fail in compression due to microcrack growth and coalescence, while cubes fail due to the axial macrocracks that develop at the specimen/load platen interface and propagate into the specimen parallel to the loading direction (end splitting). This work demonstrates the impact of compositional variation, tailored by additive manufacturing, on the mechanical performance of ceramic composites.

Phenotyping methodologies of log end splitting in eucalyptus (Eucalyptus spp.)

AbstractThis study addresses the crucial consideration of log end splitting in breeding programmes for treated wood. There is a paucity of research focused on efficiently optimizing the phenotyping process for this particular trait. The study aimed to compare methodologies for log end splitting phenotyping and develop an image‐based crack evaluation approach. Initially, 32 eucalyptus clones underwent phenotyping using manual measurement, digital image analysis and visual evaluation. Results showed similar phenotypic values, but image analysis demonstrated better clone discrimination, reducing evaluation time to 78 h compared to manual measurement. The second part focused on testing convolutional neural network architectures (UNet, LinkNet and FPN) using real and synthetic images. U‐Net exhibited slight superiority based on higher Intersection over Union (IoU) values, exhibiting a high correlation (.89) with true values. This approach significantly reduced evaluation time to approximately 10.15 h, emphasizing its efficiency compared to traditional methods.

Can diameter and log end splittings be a good indicator of board end splitting in 21-year-old Eucalyptus grandis Hill ex-Maiden?

Eucalyptus spp. are currently cultivated in Brazil. In this article we highlight Eucalyptus grandis with its potential for mechanical processing. After felling trees, the splitting that occurs at the end of logs and boards obtained during mechanical processing represents an indirect measure of the level of growth stress present in the living trees. Even though such splitting can cause significant losses in the use of wood, knowledge of this pattern is still sparse. The most suitable eucalyptus trees for the production of sawn wood can be selected by evaluating the effect of the release of growth stresses in the form of cracks. To address this gap, we herein evaluate the effects of end splitting in logs and boards, resulting from the release of growth stresses during the felling of trees and mechanical processing, as a function of the diameter of 48 Eucalyptus grandis Hill ex-Maiden trees aged 21 years old. Splitting at the ends of boards in the green and dry states have a low relationship with the diameter of the logs, but it is not related to the end splitting of the tree logs. A high positive relationship was found between dry board splitting and green board splitting. Therefore, it is possible to estimate with accuracy the evolution of green board splitting according to the drying of the wood. Boards lose, on average, 44 cm (15%) from cracks, or an average of 32 cm (11%) from growth stresses and 12 cm (4%) from drying stresses. Green and dry board splitting decreased significantly from pith to bark. The splitting of dry and green boards had no significant variation between the analyzed positions of the log along the height of the tree.

Study on the Milling Machinability of Bamboo-Based Fiber Composites

Bamboo-based fiber composites, known as recombinant bamboo, have emerged as a new material in the construction and decoration industry. With its excellent mechanical and ornamental properties, recombinant bamboo is gaining popularity. However, its high hardness and abrasion resistance pose challenges in the milling process. To address this, we conducted an experimental study to investigate the milling machinability of recombinant bamboo. We studied the impact of various factors—fiber angle, feed rate, and spindle speed—on the tangential and normal roughness of milled surfaces. Our findings indicated that increasing the spindle speed within an acceptable range can effectively mitigate issues such as carbonization and endface cracking on a milled surface. Additionally, we developed a prediction model to assess the probability of end splitting in recombinant bamboo. This research aimed to enhance the milling quality of recombinant bamboo, improve control over surface roughness, reduce the likelihood of end splitting, and, ultimately, expand application possibilities.

Axial compression capacity analysis of prefabricated steel reactive powder concrete columns in prefabricated modular buildings

This article proposes a prefabricated steel reactive powder concrete (PSRPC) component. Axial compression tests are conducted with five 3m full-scale column specimens to investigate the specimen damage and failure process and to measure the axial displacement, strain and ultimate bearing capacity in order to study the influences of the RPC strength and the section steel flange thickness on the mechanical properties of the PSRPC. The tests show the following. The ultimate failure mode of the PSRPC is column end splitting. During the loading process, the RPC and the section steel work compatibly, and their strengths are given full play. The lateral effect of the RPC on the section steel and the composite confinement effect of the stirrups and section steel on the RPC core significantly increase the ultimate bearing capacity of the PSRPC, and these effects increase with an increase in the RPC strength. The confinement effect on the RPC core in the enclosed region increases with an increase in the section steel flange thickness, that is, the thicker the section steel flange, the larger the portion of the load taken by the RPC core and the higher the ultimate bearing capacity of the PSRPC. The finite element analysis of PSRPC specimen is carried out by ANSYS software, and the simulation results are in good agreement with the test results. A method for calculating the axial bearing capacity of a full-scale column is proposed, taking the confinement effect of the stirrups and section steel on the RPC core into account.

Corrective Interventions to End-Splitting and Surface Cracking in Kenya Grown <i>Eucalyptus grandis</i> Poles

This study determined the effect of three pole pre-drying handling techniques, on end-splitting and surface checking in Eucalyptus grandis poles from highland and low land areas in Kenya. A total of 144 Eucalyptus grandis trees were sampled from two sites; Kericho, representing the wet highlands and Londiani representing the drier lowlands regions of Kenya. Pole samples from both sites were subjected to the three pre-drying handling techniques for the first 30 days after felling and allowed to dry to the required moisture level under observations. The number of end splits and surface checks on each sample pole were counted and the length of the worst ones was measured in millimeters after every 15 days until all the poles reached 25% MC. The sap wood and heart wood ratios were determined from selected samples. Results showed that on the overall, poles from high land areas had the highest sapwood proportions and similarly had the highest number and the longest end splitting and surface checks. On the other hand, pre-drying techniques that allowed felled trees to dry slowly with their foliage intact for the first 30 days of felling produced the best quality poles, with fewer and shallower end splits and surface checks. The study recommended that felling and leaving poles to dry slowly with foliage intact be considered in reducing losses incurred as a result of wood stresses during drying of poles.

Prevention and treatment of complications in the treatment of femoral shaft closed fracture with core drilling intramedullary nail

To summarize the complications of core drilling intramedullary nail in the treatment of femoral shaft closed fracture and explore the treatment strategy. From August 2014 to June 2018, a total of 215 patients with closed femoral shaft fractures were treated with closed reduction core drill intramedullary nail, including 129 males and 86 females, aged from 18 to 62 years, with an average of (44.2±10.6) years old. The time from injury to operation was 3 to 21 days. There were 102 cases of AO type A fracture, 82 cases of AO type B fracture and 31 cases of AO type C fracture. The time of operation, the amount of blood loss during operation, the duration of hospitalization, the time of fracture healing and the HSS score of knee joint function at the last follow-up were recorded. The observation of complications included:iatrogenic fracture, core drill broken, core drill twist, postoperative infection, and fracture nonunion. The average operation time was (63.2± 15.6) min and intraoperative blood loss was (150.0±34.5) ml. All the incisions reached grade A healing. Patients were follow up for a mean of (18.5±3.2) months, the average hospital stay was (4.3±1.2) days, and the average fracture healing time was (5.6±2.3) months. At the final follow-up, the average HSS score of knee joint was 90.3±4.7. Related complications occurred in 37 cases (17.2%). The core drill related complications occurred in 13 cases (6.0%), including core drill broken in 5 cases (2.3%), core removal in 1 case and slotting in 4 cases;core drill twist in 8 cases (3.7%). After the core was cut, the core was removed. Similar complicationsof conventional intramedullary nail:iatrogenic fracture was performed in 12 cases (5.6%), including 10 cases of fracture end split and 2 cases of distal perimedullary fracture of intramedullary nail. The patients with cleavage at the fracture end were not treated after judging their stability, and the patients with fracture around the distal end of the intramedullary nail were fixed with auxiliary steel plate during operation;1 case(0.4%) with delayed infection after operation, debridement and external fixation was replaced and healed after bone transfer; fracture nonunion occurred in 11 cases (5.1%), of which 7 cases (3.3%) were hypertrophic nonunion and healed with additional plate. Atrophic nonunion occurred in 4 cases (1.9%), which healed after additional steel plate and bone graft. Core drilling intramedullary nail is an effective method for the treatment of closed femoral shaft fracture, and the complications include core drill related complications and conventional intramedullary nail similar complications. Accurate preoperative evaluation, careful operation during operation and early postoperative symptomatic treatment can effectively reduce the occurrence of related complications.

Prediction of End Splitting in Log of Eucalyptus Nitens (H. Deane & Maiden) Maident through Regression Models Using Longitudinal Residual Strain, Physical and Dendrometric Properties

The objective of this research was to develop regression models, with the purpose of estimating the growth stresses and end splitting, in 12-yr-old Eucalyptus nitens trees located in the province of Valdivia, Chile. A total of 40 trees were samples. Their longitudinal residual strain (LRS) was measured using the CIRAD-Forêt method and compared with the Council of Scientific and Industrial (CSIR) index and with a new index proposed in this investigation, called the splitting index. Physical and dendrometric properties of each selected tree were measured to identify possible correlations between these variables. These predictors were analyzed statistically, allowing the development of regression models, which showed a coefficient of determination (r2) of 0.783 and 0.770 to predict the LRS and CSIR indexes, respectively. Finally, a relatively robust regression model was developed to predict end splitting in logs using LRS and physical and dendrometric parameters.

Incidence and Severity of End-Splitting in Plantation-Grown Eucalyptus pellita F. Muell. in North Borneo

Eucalyptus pellita F. Muell. is currently the predominant tree species deployed for tree plantation establishment in some parts of Borneo, particularly Sabah state, Malaysia. Its low disease susceptibility, good growth and form, and desirable wood properties make E. pellita particularly suitable for plantation development in the wet tropical regions of south-east Asia. In spite the many positive traits, practical field observations indicate that the species is susceptible to end-splitting. There is some anecdotal evidence to suggest a genetic relationship with the incidence of end-split, although these observations were not statistically tested. This study evaluates the occurrence of end-splitting in five-year old plantation E. pellita in Sabah as affected by family and growth attributes. An existing progeny tree breeding trial, involving seeds that originated from Papua New Guinea, China, Vietnam, Australia, Sabah, and Sarawak with 106 families, was used to carry out the split assessment. Logs from the second thinning were cut into 2.2-m-long sections. The end splits were measured three days later; the incidence and severity of splitting were assessed at both the large and small ends of each log by using a designated split scoring system. The study shows that 99% of all log cross sections (per cut surface) experienced signs of splitting, with an average of 2.7 splits per cut surface. Overall, 54% of all splits were classed as ‘Three-Quarter Radial Splits’ while the occurrence of internal splits was negligible. Split severity showed a heritable and significant difference (h2 = 0.24 at p ≤ 0.05) among the family levels. Splitting was also significantly related to growth factors such as tree height and diameter at breast height (DBH). The findings suggest that end-splitting is caused by family–environment interactions. This offers the opportunity to improve the wood resource of E. pellita via breeding strategies.

Effect of growth stress and interlocked grain on splitting of seven different hybrid clones ofEucalyptus grandis×Eucalyptus urophyllawood

AbstractTrees with high levels of growth stress begin to show log end splits (LES) immediately after harvesting, usually reaching its maximum end split in a week, and these tensions also create splits during lumber manufacturing. Interlocked grain is another characteristic that impacts the properties of eucalyptus wood. The aim of this study was to evaluate the effect of growth stress and interlocked grain patterns on log end splitting of seven different hybrid clones ofEucalyptus grandis × Eucalyptus urophyllaplanted in Brazil. The growth stress indicator (GSI) was measured in standing trees before harvesting. Splits were measured on logs in three different stages, and interlocked grain from wood blocks was obtained across the center of the cross-section. The results showed that LES occurred as soon as the trees were harvested; however, for better selection of clones, LES should be evaluated after a week of harvesting. There were statistically significant correlations for GSI with LES. Clones that presented higher values of interlocked grain tended to develop lower values of GSI and LES. Using GSI and interlocked grain measurements, it was possible to select the most indicated eucalyptus clones for lumber production.

Drying influence on the development of cracks in Eucalyptus logs

The aim of this study was to evaluate the effect of the moisture loss, diameter, and wood density on the appearance of surface cracks and end splits in Eucalyptus urophylla logs. The drying and emergence of defects were evaluated in 108 logs with diameters ranging from 60 mm to 150 mm from the initial moisture content to the equilibrium moisture content. The defects were measured during this time. Smaller diameter logs dried faster than larger diameter logs and took less time to reach the fiber saturation point. Surface cracks tended to develop during the loss of bound water. End splits developed during free water loss and continued to appear during bound water loss. Smaller diameters presented higher percentages of surface cracks compared with larger diameters, while larger diameters had a tendency for higher percentages of end splits compared with smaller diameters. The density did not influence the total emergence of end splits, but it did influence the total emergence of surface cracks, indicating a possibility for the selection of genetic material with lower tendency for cracking. Overall, the results reinforce the need to control drying at its beginning in order to decrease the risk of defects.

Potential of Veneer Peeled from Young Eucalypts in Laos

In Laos and neighboring countries, opportunities exist for the production of engineered wood products such as plywood and laminated veneer lumber to supply the rapid growth of construction, furnishing, and joinery activities. The objective of the present study was to assess the potential of peeling fast-growing high-yielding pulpwood from managed eucalypt stands in Laos for veneered products. Eucalyptus pellita, Eucalyptus camaldulensis, and eucalypt clone K7 (E. camaldulensis × E. deglupta) stands were characterized based on veneer quality and recovery. The influence of log position, log geometry, and other log traits during recovery were also investigated. The selected taxa achieved green veneer recoveries that ranged between 57% and 67%. End splitting and branch-related defects were the most important grade-limiting defects that restricted veneer sheet quality to a lower grade of most sheets. However, simple timely silvicultural decisions, such as pruning, could significantly help improve the quality of veneer obtained. The obtained results could be used in the formulation of recommendations to adopt better management practices in Laos to improve the value of plantation-grown wood.

Growth strain in straight and inclined Populus × euramericana cv. ‘74/76’ trees, and its relationship with selected wood properties

Growth stress is important to achieve upright growth and avoid exterior influence on living trees. However, many problems are also triggered by the release of growth stress during wood processing, such as end split of log, distortion of board and inaccurate sawing. In order to evaluate the possibility of these problems to occur in poplar clone 107, a new breeding poplar clone in China, surface longitudinal growth strain (SLGS) and internal longitudinal growth strain (ILGS) both of straight and inclined trees were measured for depicting distributing patterns of growth strain both in peripheral and radial directions. Besides that, according to one-way ANOVA analysis, individual tree and peripheral position have a significant effect on SLGS in inclined trees, whereas such effect is insignificant in straight trees. Fiber morphology and shrinkage of wood sample beneath the SLGS testing positions were determined to illustrate the relationships between these properties with SLGS. The results suggested that growth stress is a poor indicator of fiber morphology and wood shrinkage properties for straight trees but a good one for inclined trees. Both the positive SLGS and ILGS are unexpectedly found at the opposite wood side of inclined trees. It is speculated that when the reorientation of inclined trees is insufficiently supported by exerting tensile stress at tension wood side, compressive stress will be formed at the opposite wood side as a complement.

Finite element analysis of stress-related degrade during drying of Corymbia citriodora and Eucalyptus obliqua

With the use of experimental wood properties and input moisture content field data, a predictive 3D stress–strain finite element analysis (FEA) model was developed allowing to predict the development of stress-related end splitting and surface checking degrade during conventional and vacuum wood drying. Simulations were carried out for two Australian hardwood species, messmate (Eucalyptus obliqua) and spotted gum (Corymbia citriodora), as these species contrast, in terms of wood properties, drying rates and stress degrade susceptibility. The simulations were performed using a 1/8 symmetry model where the full board dimensions are 1900 mm long × 30 mm thick × 100 mm wide. Moisture content field data model simulations were utilised in a three-dimensional FEA model by extruding a 2D moisture content field computed in the T–L plane across the radial direction to create a 3D model. Material mechanical properties and shrinkage were calculated in relation to moisture content, over discrete time intervals, using a quasi-static solver. End split failure was investigated at the board end, and surface check failure at the board surface, using a Tsai–Wu failure criterion. Simulations showed that messmate was more susceptible to end splitting than spotted gum and that conventionally dried messmate was more susceptible to surface checking than vacuum-dried messmate. The same results were observed from drying trials. The locations of predicted surface check failure also matched drying trials and are compared.

DETERMINAÇÃO DO RENDIMENTO DE MATÉRIA-PRIMA DE Eucalyptus benthamii Maiden & Cambage POR MEIO DE DIFERENTES MÉTODOS DE DESDOBRO

RESUMOO objetivo deste trabalho foi determinar o rendimento da matéria-prima de Eucalyptus benthamii, por meio dos desdobros tangencial e radial, além da classificação das toras quanto à presença das rachaduras de topo. A classificação das toras quanto às rachaduras foi realizada por meio da análise visual, em que era aplicado um conceito conforme a intensidade do defeito. Posteriormente, as toras foram separadas em duas classes diamétricas (20 a 25 e 25,1 a 30 cm) e processadas em três sistemas de desdobro (tangencial em bloco, radial e tangencial em bloco com face curva), sendo cada tratamento composto por três repetições com 10 toras cada um. Na análise estatística dos dados de rendimento, foram aplicados o teste de Kolmogorov Smirnov, a Análise da Variância e o teste de Tukey. Nos resultados, foi observado que a maioria das toras da classe de menor diâmetro apresentou intensidade mediana, enquanto na maior classe diamétrica a intensidade foi baixa. Os rendimentos médios líquidos encontrados foram de 43,5% e 39,2% nas classes inferior e superior, respectivamente, os quais foram influenciados pelas rachaduras das peças e pelos destopos. Observou-se que o desdobro tangencial em bloco e em face curva foram os métodos que apresentaram maior aproveitamento em madeira serrada na classe de 20 a 25 cm, enquanto na classe de 25,1 a 30 cm o sistema tangencial em bloco e radial foi equivalente.

Factors affecting log traits and green rotary-peeled veneer recovery from temperate eucalypt plantations

High levels of percentage green veneer recovery can be obtained from temperate eucalypt plantations. Recovery traits are affected by site and log position in the stem. Of the post-felling log traits studied, out-of-roundness was the best predictor of green recovery. Eucalyptus globulus and Eucalyptus nitens are widely planted in temperate regions of the globe but few studies of rotary peeling have been documented. This study aims to examine differences among sites and log positions in post-felling log traits and green veneer recovery traits and determine the extent to which log traits explain variation in recovery traits. Log traits and green rotary-peeled veneer recovery traits from six temperate eucalypt plantations were studied. Selected plantations encompassed different age, site productivity, silvicultural and species classes in south-eastern Australia. Differences in log and recovery traits among sites and between lower and upper logs were examined, as was the extent to which log traits explained variation in recovery traits. Differences among sites for percentage recovered green veneer were non-significant, despite significant differences for peelable billet volume, roundup loss, residual core diameter and all post-felling log traits: small end diameter, sweep, taper, out-of-roundness, end splitting and dynamic modulus of elasticity (MOEdyn). The lower log exhibited more sweep, taper and out-of-roundness but lower MOEdyn and less recovered green veneer. Out-of-roundness was the best predictor of recovery traits (R 2 = 13–21 %, P < 0.001). Recovered green veneer was high across all sites and log positions (78 % overall).

Splitsville: Independent Exhibitors Court Federal Intervention in the American Film Industry, 1975–1988

On the eve of its decision not to enforce the Paramount consent decrees, the US Department of Justice (DOJ) began to prosecute film exhibitors over the practice of splitting. Exhibitors had used splitting—dividing films among themselves to reduce competition in the bidding process—to ameliorate the film studios’ power. When a group of independent exhibitors alleged collusive behavior between the studios and national theatrical chains, the DOJ acted to end splitting. Ironically, the DOJ’s final antitrust action against the film industry in the consent decree era would be against exhibitors, the class it had previously acted to protect.

Split-Current Magnetoresistor

The split-current magnetoresistor is proposed here. The structure likes the series magnetoresistor that one end split into two symmetrical terminals, so it is the magnetoresistor with three terminals. It uses the Hall effect current mode as magnetoresistor but the output is the differential current instead of resistance. It shows good linearity and can detect the magnetic field direction. The sensitivity in the differential current of width 100 μm and length 200 μm at 1 mA is 2.788x10-6 A/T constantly while the conventional one in the differential resistance is varied with magnetic field. It is made of silicon non magnetic material so it is compatible with the modern low-voltage current-mode integrated circuit.

Influência da classe diâmetrica nos índices de rachadura da madeira em Liquidambar styraciflua

The growth stresses of trees can be evaluated by means of the analysis of the end splitting on green and dry boards. Thus, this work aimed to study the evolution of the splitting length during the process of natural drying in the sawn wood of 24-year-old Liquidambar styraciflua, as a function of different diameter classes (upper, middle and lower) and two vertical positions along the stem commercial height. According to the results obtained, it was possible to conclude that the end splitting on green and dry boards was influenced only by the diameter class, where the upper class presented the greatest length of splitting while the lower class showed the smallest length. A strong relationship between the end splitting of dry board and green board was verified.