Log Storage Research Articles

Effects of elevation and aspect on the flight activity of two alien pine bark beetles (Coleoptera: Curculionidae, Scolytinae) in recently-harvested pine forests

Climate is an important driver of the establishment and impact of invasive alien species. Species transported to new regions can only invade those with a climate that meets their thermal requirements, but climate change is likely to alter the invasibility of recipient environments. Likewise, species are unlikely to reach pest status where climatic conditions are suboptimal. Here our objectives were to determine the relationship between climatic conditions and flight activity of two alien pine bark beetles (Hylastes ater and Hylurgus ligniperda) and to anticipate how climate change may affect the future distribution of these species. We used elevational gradients and slope aspect (north versus south-facing slopes), which are known to affect microclimates, to assess the effects on beetle flight across 18 locations in pine forests in the South Island, New Zealand. Using panel traps baited with alpha-pinene and ethanol we caught a total of 45,363 H. ligniperda and 6676 H. ater. Catches of both species decreased significantly and substantially with increasing elevation. Significantly more beetles were caught at north-facing than at south-facing sites towards the end of the flight season in autumn, leading to an extended flight period at northerly aspects. These results are important for pest management and the identification of ‘areas of low pest prevalence’ as a measure to reduce post-harvest infestations of logs destined for export. For example, during risk periods, logs could be harvested preferentially from stands with reduced flight activity (i.e., southerly aspects and higher elevations). Furthermore, such sites could be chosen to reduce post-harvest infestation risks during periods of temporary log storage at skid sites in the forest. Our findings are also important because climate change can be an important factor contributing to population expansion of bark beetles, and warmer temperatures could lead to increased flight activity and abundance, as well as enhanced suitability of sites that are currently less favourable.

Influence of site, storage and steaming on Eucalyptus nitens log-end splitting

Log-end splitting is one of the single most important defects in veneer logs. We show that log-end splitting in the temperate plantation species Eucalyptus nitens varies across sites and within-tree log position and increases with time in storage. Log-end splitting is one of the single most important defects in veneer logs because it can substantially reduce the recovery of veneer sheets. Eucalyptus nitens can develop log-end splits, but factors affecting log-end splitting in this species are not well understood. The present study aims to describe the effect of log storage and steaming on the development of log-end splitting in logs from different plantations and log positions within the tree. The study was conducted on upper and lower logs from each of 41 trees from three 20–22-year-old Tasmanian E. nitens plantations. Log-end splitting was assessed immediately after felling, after transport and storage in a log-yard, and just before peeling. A pre-peeling steam treatment was applied to half the logs. Site had a significant effect on splitting, and upper logs split more than lower logs with storage. Splitting increased with tree diameter breast height (DBH), but this relationship varied with site. The most rapidly growing site had more splitting even after accounting for DBH. No significant effect of steaming was detected. Log-end splitting varied across sites and within-tree log position and increased with time in storage.

비밀분산 기법과 Subset Difference 기법을 이용한 브로드캐스트 암호시스템

Broadcast encryption is a cryptographic primitive that allows a sender to securely broadcast a message to a set of receivers. The most influential broadcast encryption system was proposed in 2001 by Naor, Naor, Lotspiech, based on a pseudo-random generator and the Subset Difference (SD) method. In this paper, we suggest a new broadcast encryption system that is based on secret sharing and SD methods. On an efficiency aspect, our system achieves  transmission cost, log   storage cost, and  computational cost for the number  of users and the number  of revoked users. Compared to log computational cost in the previous SD method, our system has the advantage that it needs only constant-sized computational cost for decryption, regardless of the number  or . On a security aspect, our system can achieve tighter security reduction than the previous SD method and the gap of security loss is about log. Moreover, our result shows that it is possible to give the effect of the SD method while using an information-theoretically secure key distribution technique as in the Complete Subtree method.

비휘발성 캐시를 사용하는 플래시 메모리 SSD의 데이터베이스 로깅 성능 분석

In a database system, updates on pages that are made by a transaction should be stored in a secondary storage before the commit is complete. Generic secondary storages have volatile DRAM caches to hide long latency for non-volatile media. However, as logs that are only written to the volatile DRAM cache don't ensure durability, logging latency cannot be hidden. Recently, a flash SSD with capacitor-backed DRAM cache was developed to overcome the shortcoming. Storage devices, like those with a non-volatile cache, will increase transaction throughput because transactions can commit as soon as the logs reach the cache. In this paper, we analyzed performance in terms of transaction throughput when the SSD with capacitor-backed DRAM cache was used as log storage. The transaction throughput can be improved over three times, by committing right after storing the logs to the DRAM cache, rather than to a secondary storage device. Also, we showed that it could acquire over 73% of the ideal logging performance with proper tuning.

Softwood sawlog secondary transport travel speed prediction for the South African forestry industry

The objective of this study was to develop a predictive model for travel speed of softwood sawlog timber transport (STT) vehicles over a range of forest and provincial roads of varying condition for the South African forestry industry. Data was accumulated from both the Eastern Cape/KwaZulu-Natal and Mpumalanga forest regions of South Africa. Vehicle location and payload data were collected remotely using a combination of GPS tracking and remotely sensed data. Road condition, including road width, was assessed for each identified road segment in-field according to a visual condition indicator (VCI) index. Two STT contractors were selected from each forest region transporting pine sawlogs directly from compartment roadside landings to either a processing plant or log storage area. Five STT vehicle types, representative of transport operations in the two forest regions, were assessed. Principal component analysis was conducted to determine the degree of communality between the respective predictor variables combining road width and VCI as one factor, and truck maximum power and the percentage of (legal) maximum payload as a second factor. Comparisons of the correlations between average speed and the respective predictor variables showed that road width and percentage of maximum (legal) payload had the highest correlations. Multiple linear regression of these two factor variables were used in the model showing both variables as significant (p < 0.05) with an adjusted r2 value of 0.52.

Zing Database: high-performance key-value store for large-scale storage service

Nowadays, key-value stores play an important role in cloud storage services and large-scale high-performance applications. This paper proposes a new approach in design key-value store and presents Zing Database (ZDB) which is a high-performance persistent key-value store designed for optimizing reading and writing operations. This key-value store supports sequential write, single disk seek random write and single disk seek for read operations. Key contributions of this paper are the principles in architecture, design and implementation of a high-performance persistent key-value store. This is achieved using a data file structure organized as commit log storage where every new data are appended to the end of the data file. An in-memory index is used for supporting random reading in the commit log. ZDB architecture optimizes the index of key-value store for auto-incremental integer keys which can be applied in storing many real-life data efficiently with minimize memory overhead and reduce the complexity for partitioning data.

Secure Audit Log Management

Log management and analysis is a vital part of organization's network management and system administration. Logs indicate current status of the system and contain information that refers to different security events, which occur within the system. Logs are used for different purposes, such as recording user activities, track authentication attempts, and other security events. Due to increasing number of threats against networks and systems, the number of security logs increases. However, many organizations that work in a distributed environment face following problems: log generation and storage, log protection, and log analysis. Moreover, ensuring that security, system and network administrators analyze log data in an effective way is another issue. In this research, we propose an approach for receiving, storing and administrating audit log events. Furthermore, we present a solution design that in a secure way allows organizations in distributed environments to send audit log transactions from different local networks to one centralized server.

Preparation and properties of in‐situ polymerized polyurethane/stearate intercalated layer double hydroxide nanocomposites

AbstractThe present work deals with the effect of stearate intercalated layered double hydroxide (St‐LDH) loadings on the morphological, mechanical, thermal, adhesive and flame retardant properties of polyurethane (PU)/St‐LDH nanocomposites prepared by the in situ polymerization method. X‐ray diffraction and transmission electron microscopy studies confirmed that exfoliation takes place at 3 wt% loading followed by intercalation at higher filler loadings in the PU matrix. The exfoliated structure has been further verified by atomic force microscopy. The measurements of stress‐strain, thermogravimetric analysis, dynamic mechanical analysis, lap shear strength and peel strength analysis showed that the nanocomposites containing 3 wt% St‐LDH exhibit excellent improvement in tensile strength (ca 175%) and log storage modulus (ca 14%), while PU/St‐LDH (5 wt%) possesses optimum improvement in glass transition temperature (ca 6 °C), lap shear strength (200%) and peel strength (130%) over neat PU. In addition, the gradual improvements in limiting oxygen index value with St‐LDH loading indicated the higher effectiveness in providing better barrier properties as well as better flame retardant behavior. Copyright © 2012 Society of Chemical Industry

Syslog a Promising Solution to Log Management

Log data are very useful in the changing scenario as it contains information related to types of events/attacks occurring within an organizations network. Log data are also very useful to track the history of an intruder’s activity in day-to-day work and providing evidence to investigate malicious activity. Hence log files, which are most significant for cyber security investigation, should be stored in a secured place so that intruders will not be able to alter or erase log files. In order to protect the log data from breaches of their confidentiality and integrity log management is required in almost all enterprises. Windows event log has too many limitations, which becomes the biggest challenge in the process of log management. One of the limitations of windows event log is that, it is incapable of handling of messages from network devices such as routers and switches. Also there are no native window tools available to facilitate the centralization of logging process from different log sources in an organization where as Syslog offers very efficient solution to centralize the logging function. The proposed solution strongly recommends using syslog for the log management process. The proposed architectural model is very efficient to capture log data from anywhere in an organizations networks. The solution proposed here greatly simplifies the process of log storage and analysis by centralizing the logging process from all the devices present in the network and also provide a secured storage for the log data. The proposed model also makes it possible for Windows event log to be compatible with the logging function of other operating system. Keywords: Syslog, Audit logs, Cyber security, Windows Event logs, Log management.

Measuring the Moisture Content of Green Wood Using Time Domain Reflectometry

The responsible usage of water by facilities that rely on wet log storage in the southern United States has become an issue of great importance as restrictions on water usage have grown in recent years. In order to learn about the dynamics of moisture content in wet-stored logs over time, it is necessary to conduct continuous monitoring of log piles. Time domain reflectometry (TDR) is a method that current research has shown to have potential for use in this area. In this study, TDR probes of three lengths (75, 100, and 125 mm) were systematically inserted into 39 saturated bolts of Pinus taeda L., and both TDR and moisture content measurements were taken nine times over a period of 16 days as the bolts air dried. The samples were then oven dried, and measurements were taken three more times during that process. TDR readings from the 125-mm probes had the strongest relationship (R2 = 0.9426) with moisture content measurements. This result indicates TDR readings are sufficiently correlated with moisture content to accurately predict moisture variation over time and can be used to learn how water application and other factors affect the moisture content of wet-stored logs.

Methodology for planning log stacking using geotechnology and operations research

In view of the need to improve the planning of timber harvest and transportation, with both activities being the most influential in determining the final cost of timber delivered to the mill yard, this work aims to develop a new methodological proposal using operations research and geotechnology tools in order to determine optimal locations for log stacking and also the amountof timber to be allocated to each selected stack. Analysis was performed using two software applications, geographic information system (GIS) and operations research (OR). GIS spatial analyses were based on layers of the study site, which is a property owned by Votorantim Celulose e Papel, located in the municipality of São José dos Campos, in order to obtain three variables: degree of difficulty in operating forestry equipment, degree of difficulty in log stacking, and distance between log stacks and existing roadways. To obtain these variables, layers containing information on terrain inclination and existing roadways were combined in another analysis named weighted overlay. Results were then filtered and inserted into an operations research environment for maximizationof the timber volume in each selected stack. With results obtained from the geographic information system, 80 potential sites were selected for log stacking. By using operations research, 59 of these sites were ruled out, a 73% reduction in the number of potential sites, with only 21 sites remaining as potentially optimal for log storage. For each of these 21 sites, an optimal amount of timber wasdetermined to be allocated to each one of them.

Suckering response of aspen to traffic-induced-root wounding and the barrier-effect of log storage

In a growth chamber, we tested how the seasonal timing of placing a physical barrier (simulating a possible effect of log storage) and inflicting root damage impacted aspen ( Populus tremuloides Michx.) root systems and their suckering capability. Roots from 4-year-old saplings were used, and one half of these root systems had the above-ground portion cut in the winter (dormant) while the other half was cut during the growing season in the summer. Damage was inflicted to the roots by driving a large farm tractor over them, and a covering treatment was applied using a polystyrene board to prevent suckers from emerging from the soil. Soil temperatures for the winter-cut root systems were kept at 5 °C over the growing season, using a water bath, while for the summer-cut root systems soil temperatures were maintained at 17 °C over the growing season. In the winter-cut root systems, both log storage and root wounding caused a 40% reduction in living root mass and carbohydrate reserves, as well as reducing sucker numbers and their growth performance. In the summer-cut root systems log storage and root wounding reduced living root mass by approximately 35% as well as sucker growth, but had less of an impact on the number of suckers produced.

Aspen regeneration on log decking areas as influenced by season and duration of log storage

This study assessed aspen regeneration on decking areas as affected by season of log deck building and duration of log storage; as well as root wounding, soil compaction, and slash depth. On former decking areas that were built after a summer harvest, aspen regeneration was 50% lower and root death 35% greater compared to former decking areas of a fall harvest. Duration of log storage after a fall harvest had little effect on aspen regeneration; short (1.5–3 months) or long (11 months) storage resulted in similar regeneration. Slash load was greatly increased on decking areas while root wounding and soil bulk density were only slightly increased compared to controls. For best management practices, log storage after summer harvest should be avoided especially when logs are kept over the growing period when suckering occurs. Additionally, removing the interwoven mat of slash covering decking areas and limiting machine traffic to frozen soil will ensure vigorous suckering.

Effects of log storage conditions and steaming process on the formaldehyde emissions of particleboard manufactured from eucalyptus (E. camaldulensis) wood

The aim of this study was to determine the changes in formaldehyde emissions of eucalyptus particleboards produced from logs stored under different conditions (indoor, outdoor, and under water) or steamed. The pH and Stiasny values of particles changed significantly according to the storage condition and log steaming process. The pH values of particles obtained from steamed logs and stored outdoors for 4 months were found to be lower than those of the particles obtained from logs stored in the other aforementioned two conditions. The peaks of acetyl groups in the IR-spectra of the four group particles were similar. There was a strong relationship among the formaldehyde emission values of the panels pressed at 150 °C and the Stiasny values of the particles from which the panels were produced. The formaldehyde emission values of the panels pressed at 190 °C were lower than those of the panels pressed at 150 °C.

The influences of log storage and kiln drying climate on the colour of non-steamed beech (Fagus sylvatica L.) wood

Discolouration during the drying of non-steamed beech is a major industrial concern. The generally preferred yellow-white colour can easily develop a reddish or dull grey appearance during drying. In this study, the influences of log storage time and kiln drying climate on the colour of non-steamed sawn beech have been investigated and quantified. Samples 27×87 mm in cross section were dried in laboratory kilns and the average colour, in CIELAB colour space was measured on dry planed surfaces using a photoelectric colorimeter. Log storage for 13 weeks under low-temperature conditions had no visible effect. The reddish discolouration is mainly temperature related while the greyish discolouration is mainly controlled by the equilibrium moisture content (EMC) during the initial drying. Within the investigated climate interval, the EMC was twice as important as temperature for the final colour. Regression models developed show that, as long as the EMC is kept below 15%, a temperature of up to 37°C can be allowed without any visually detectable discolouration.

Impact of Aspen Log Storage with and without Protection on OSB Performance

Outdoor log storage without protection can change the mechanical and chemical properties of wood due to infection by various fungi. To understand how outdoor log storage affects the wood and, subsequently, the strandboard quality, two piles of aspen logs were set up outside and stored for a period of four months (July to November). One of the piles was treated with a biological solution to prevent fungal growth. The other one was stored without treatment. Both piles contained non-debarked and partially debarked logs. Evaluation of sap stain development indicated that all logs had been colonized by staining fungi with average stain coverage of 9.37 to 57.18% and maximum stain penetration of 3.58 to 7.27 cm over the log cross section. The variation of fungal colonization depended on log treatment and bark condition. The most effective way to prevent stain growth was the combination of biological treatment and partial debarking. A series of strandboard was prepared from fresh and aged aspen logs. All boards made from stored logs were statistically comparable to or superior to the control boards made from fresh aspen logs. The boards made from treated/partially debarked and untreated/non-debarked logs were statistically comparable to each other except for wet MOR. In addition, these two board types were statistically stronger than other boards made from treated/non-debarked and untreated/partially debarked logs in terms of IB and water resistance. Some individual stained strands were observed on the finished board surface. Less staining was found in the boards prepared from biologically treated and partially debarked logs, compared with those made from other stored logs.

Isolation of wood-inhabiting fungi from Canadian hardwood logs

Wood-inhabiting fungi include many molds, wood-staining fungi, and decay fungi. Most of these fungal species can result in economic losses to wood users. Studies on molds, staining fungi, and decay fungi are necessary to be able to control their growth on wood and wood products. In this study, wood-inhabiting fungi were isolated from logs of 3 major Canadian hardwood species: sugar maple, white birch, and yellow birch. Two media were used for isolation. From these 3 wood species, a total of 1198 fungal cultures were obtained from summer- and winter-harvested logs in dry storage and under water sprinkling. The results showed that most fungal species were not host specific and affected all of the wood species tested. Frequently isolated molds were Alternaria alternata, Trichoderma species, and Mucor/Rhizopus (Zygomycota) species, frequently isolated staining fungi were Ophiostoma piceae and Ophiostoma piliferum, a frequently isolated bark saprophyte was Nectria cinnabarina, and frequently isolated decay fungi were taxa of the phylum Basidiomycota. More fungal species were isolated from summer-harvested logs than from winter-harvested logs. Fewer fungal cultures, especially decay fungi, were isolated from logs in early storage than from logs in late storage.

Effects of log storage and drying on birch (Betula pendula) wood proanthocyanidin concentration and discoloration

In conventional drying, sawn birch (Betula sp.) timber darkens and reddens from the inside while the layer a few millimetres under the yellowish surface remains light in color. Lack of information concerning the chemical basis of the discoloration hinders the development of a reliable solution for this problem. In this study, the role of soluble proanthocyanidins in discoloration of birch wood was investigated because the polymerization and oxidation of these compounds are known to yield insoluble reddish compounds. Different periods of log storage affected the synthesis of soluble proanthocyanidins during conventional drying. Concentration of proanthocyanidins also correlated with changes in the color of birch wood. Discoloration appeared differently in conventionally dried and vacuum-dried wood, which indicates that the discoloration mechanism in these drying methods may differ chemically, and/or the compounds that take part in discoloration may be different at different drying temperatures.

Influence of beech wood quality on bisulfite dissolving pulp manufacture. Part 1: Influence of log storage on pulping and bleaching

Abstract The present study investigated different log storage conditions and their influence on the processability of the wood material in pulping and bleaching. For that purpose, logs were stored for about 15 months under dry and wet conditions. Besides a detailed chemical, physical and microbial characterization of the wood, cooking trials according to the standard magnesium acid bisulfite process and bleaching experiments at various conditions using a (E/O)-Z-P-sequence were performed. The dependency of pulp yield, delignification efficiency, the course of cellulose depolymerization and brightness on the different storage conditions was evaluated. Bleaching selectivity was comparable for pulps made from fresh and wet-stored wood. In the case of pulp made from dry-stored wood, between 60% and 300% more bleaching chemicals, expressed as OXE, were necessary to obtain the target brightness. Milled wood lignin was isolated from the beech wood samples to study possible structural changes attributable to different storage conditions. Permanganate oxidation was applied to investigate the most important lignin structures. Additionally, preliminary NMR studies were performed to gain supplementary information about the composition of the lignin moieties. UV microspectrophotometry in agreement with absorption difference spectra strongly suggests that the chromophore structures present in both unbleached and bleached pulp samples predominantly originate from polyphenolic compounds, which are attached to the cell wall and are deposited in the lumina of parenchyma cells. From the results obtained so far, it can be concluded that wet storage of beech wood logs efficiently prevents the formation of chromophore compounds which negatively affect acid bisulfite pulping.

Dynamic Mechanical Properties of a Visible Light Curable Urethane Dimethacrylate Based Dental Resin

The purpose of this study was to evaluate dynamic mechanical properties of urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) based dental resin. Dynamic mechanical properties of a visible light (λ=400–500 nm) curable UDMA/TEGDMA (70:30 in wt%) resin were investigated for specimens uncured, light-cured for 40s, and heated to 175°C subsequent to the irradiation for 40s. Differential scanning calorimetry (DSC) was also employed as a complementary technique. For the light-cured specimen, two abrupt drops in the log storage modulus (E’) and two peaks in the tanδ vs. temperature curve corresponding to the glass transition were observed. The storage modulus was slightly increased with increasing temperature between the two modulus drops. The DSC experiment showed that the light-cured specimen contains residual living groups trapped by the fast reaction, which lead to further reaction during post-cure heat treatment. This further thermal reaction is considered to be responsible for the modulus increase. After heating to 175°C above the DSC exothermic peak, most of the residual groups in the light-cured specimen were found to be reacted, showing a single decrease in modulus and a single peak in the tan δ curve, and no exotherm in the DSC curve. With the aid of DSC data, the further thermal cure reaction with increasing temperature may occur within the glass transition region. The occurrence of the thermal reaction gives rise to the inaccuracy in determining the glass transition temperature (Tg).