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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The use of simulation as a decision tool for improvements in sawmill manufacturing

Thoews, Steven Eric 05 1900 (has links)
A simulation study was used to analyze the flow of products though a sawmill in order to determine where productivity improvements could be made. The sawmill analyzed is located in the interior of British Columbia, and processes a variety of species and products. The mill was selected for this reason, as it was important to determine how a change in the process will affect the piece flow and production of the various species. A simulation model of the mill was developed using the Arena 8.0 discrete event simulation software developed by Rockwell Automation. Data consisting of mill layout and flow, breakdown patterns, machine process times and downtimes, conveyor speeds, and buffer capacities were collected from the sawmill. This information was used to layout the framework in a conceptual model. The conceptual model was then used to develop the simulation model in Arena. A face validity test, combined with comparisons of model output to actual mill output was used to determine the validity of the model. After running several different scenarios processing Larch, White pine, and Ponderosa pine, it was discovered that the trimmer was the system bottleneck when both the small log and large log lines were running throughout the shift. Running under base case conditions, the model predicted an average board output of 13,147 boards. An increase in the processing capability of the trimmer resulted in the bottleneck to shift to the edger from the small log line. The OptQuest Analyzer program bundled with the Arena software was used to further analyze the shift in bottleneck to the edger from the small log line. By allowing the program to manipulate machine settings for the trimmer and edger, it was able to maximize the average board output to 17,996 boards per shift when no edger set up times were considered. If the edger setup times are used, the average board output dropped to 16,708 boards per shift. These findings were presented to the sawmill management and based on the study, they proceeded to make improvements at the trimmer. The improvements resulted in an increase of 10% to sawmill output.
2

The use of simulation as a decision tool for improvements in sawmill manufacturing

Thoews, Steven Eric 05 1900 (has links)
A simulation study was used to analyze the flow of products though a sawmill in order to determine where productivity improvements could be made. The sawmill analyzed is located in the interior of British Columbia, and processes a variety of species and products. The mill was selected for this reason, as it was important to determine how a change in the process will affect the piece flow and production of the various species. A simulation model of the mill was developed using the Arena 8.0 discrete event simulation software developed by Rockwell Automation. Data consisting of mill layout and flow, breakdown patterns, machine process times and downtimes, conveyor speeds, and buffer capacities were collected from the sawmill. This information was used to layout the framework in a conceptual model. The conceptual model was then used to develop the simulation model in Arena. A face validity test, combined with comparisons of model output to actual mill output was used to determine the validity of the model. After running several different scenarios processing Larch, White pine, and Ponderosa pine, it was discovered that the trimmer was the system bottleneck when both the small log and large log lines were running throughout the shift. Running under base case conditions, the model predicted an average board output of 13,147 boards. An increase in the processing capability of the trimmer resulted in the bottleneck to shift to the edger from the small log line. The OptQuest Analyzer program bundled with the Arena software was used to further analyze the shift in bottleneck to the edger from the small log line. By allowing the program to manipulate machine settings for the trimmer and edger, it was able to maximize the average board output to 17,996 boards per shift when no edger set up times were considered. If the edger setup times are used, the average board output dropped to 16,708 boards per shift. These findings were presented to the sawmill management and based on the study, they proceeded to make improvements at the trimmer. The improvements resulted in an increase of 10% to sawmill output.
3

Lumbering in southwest Louisiana a study of the industry as a culturo-geographic factor.

Stokes, George Alvin, January 2007 (has links)
Thesis (Ph. D.)--Louisiana State University, Dept. of Geography and Anthropology, 1954. / Vita. Abstract. HTML version of 1954 doctoral dissertation. Last viewed: 5/8/2008 Includes bibliographical references (leaves 88-92).
4

The use of simulation as a decision tool for improvements in sawmill manufacturing

Thoews, Steven Eric 05 1900 (has links)
A simulation study was used to analyze the flow of products though a sawmill in order to determine where productivity improvements could be made. The sawmill analyzed is located in the interior of British Columbia, and processes a variety of species and products. The mill was selected for this reason, as it was important to determine how a change in the process will affect the piece flow and production of the various species. A simulation model of the mill was developed using the Arena 8.0 discrete event simulation software developed by Rockwell Automation. Data consisting of mill layout and flow, breakdown patterns, machine process times and downtimes, conveyor speeds, and buffer capacities were collected from the sawmill. This information was used to layout the framework in a conceptual model. The conceptual model was then used to develop the simulation model in Arena. A face validity test, combined with comparisons of model output to actual mill output was used to determine the validity of the model. After running several different scenarios processing Larch, White pine, and Ponderosa pine, it was discovered that the trimmer was the system bottleneck when both the small log and large log lines were running throughout the shift. Running under base case conditions, the model predicted an average board output of 13,147 boards. An increase in the processing capability of the trimmer resulted in the bottleneck to shift to the edger from the small log line. The OptQuest Analyzer program bundled with the Arena software was used to further analyze the shift in bottleneck to the edger from the small log line. By allowing the program to manipulate machine settings for the trimmer and edger, it was able to maximize the average board output to 17,996 boards per shift when no edger set up times were considered. If the edger setup times are used, the average board output dropped to 16,708 boards per shift. These findings were presented to the sawmill management and based on the study, they proceeded to make improvements at the trimmer. The improvements resulted in an increase of 10% to sawmill output. / Forestry, Faculty of / Graduate
5

Breathing life : labour relations, epistemology and the body among Swazi timber workers

Laterza, Vito January 2012 (has links)
No description available.
6

Forest-mill Integration from a Transaction Costs Perspective

O'Kelly, Glen James January 2008 (has links)
Fibre sourcing is a critical strategic question for all sawmills and pulpmills, but the degree of supply integration though long-term contracts and forest ownership varies widely. The purpose of this research was to investigate the extent to which forest-mill integration patterns can be explained by the transaction cost economics (TCE) theory. TCE theory holds that organizations will choose transaction governance forms that minimize transaction costs. The TCE factors expected to influence that choice can be grouped into three categories; transaction frequency, market uncertainty, and asset specificity. Interviews with various industry representatives suggested that factors from all three categories are relevant to the question of forest-mill integration. A survey was conducted of mills in New Zealand and Sweden, providing data on their supply mix and various TCE factors. Of an estimated population of approximately 450 mills, 136 mills were sampled and 88 responded to the survey. Fractional logit models were developed to explore the factors that may influence the integration decision. Considerable evidence was found for the importance of TCE factors in driving fibre supply integration. The evidence was strongest for factors related to asset specificity, including forest owner concentration and the specificity of a mill's fibre requirements. Transaction frequency appears less important; while integration was found to be significantly associated with the number of mills an organisation has within the supply basin, the influence of mill capacity was found to vary. There was weak evidence for the importance of uncertainty, and perhaps only through the impact of forest owner concentration on market conduct. Integration was found significantly higher for pulpmills than sawmills, and higher in Sweden than in New Zealand. The latter result is difficult to explain by TCE theory, and suggests that non-TCE factors play a significant role. Survey responses also indicated that non-TCE factors are important. Further research is required to enlarge the sample size and better understand the role of TCE factors in forest-mill integration.
7

Late Pleistocene snakes (Squamata: Serpentes) from Abaco, The Bahamas

Mead, Jim I., Steadman, David W. 01 December 2017 (has links)
The late Pleistocene snake fossils from Sawmill Sink (Abaco, The Bahamas) represent five taxa: blind or thread snake (Scolecophidia indet.: either Leptotyphlopidae or Typhlopidae); Abaco boa (Boidae: Chilabothrus cf. exsul); rat snake (Colubridae: Pantherophis sp.); water snake (Natricidae: Nerodia sp.); and Cuban racer (Dipsadidae: Cubophis cf. vudii). Scolecophidia, Chilabothrus exsul, and Cubophis vudii still exist on Abaco and have been previously recovered in fossil deposits in the West Indies. In contrast, no forms of Pantherophis or Nerodia have been reported as fossils anywhere in the West Indies until now. This is the first evidence of any indigenous species of Pantherophis (living or extinct) in the Caribbean, whereas the only other indigenous Nerodia in the West Indies is the extant N. clarkii along the northern coast of Cuba. In being present on Abaco in late Pleistocene but not Holocene contexts, Pantherophis sp. and Nerodia sp. resemble 17 species that apparently did not survive the dramatic changes in climate, habitat, and land area associated with the Pleistocene–Holocene Transition in The Bahamas. It is likely that Pleistocene fossils of both Pantherophis and Nerodia will be found eventually on other Bahamian islands. With the discovery of these two snakes, the vertebrate fauna of Sawmill Sink now stands at 97 species, by far the richest in the West Indies.
8

Dioxiner och metaller i Lövselefjärdens sediment : Förstudie av Lövselefjärdens sediment med avseende på föroreningar från ett tidigare sågverk

Karlsson, Elin January 2017 (has links)
The aim of this study was to determine if and how especially dioxins but also metals (arsenic, copper and chromium) has spread and deposited in the sediments of Lövselefjärden in northern Sweden. The study was also meant to determine if these pollutions could be related to the previous sawmill that was located near the bay. A gravity sampler was used to extract sediment cores from the bottom of Lövselefjärden. Five sample locations were used, and in one of the locations three different depths were sampled. The results show a similar distribution of the dioxin congeners between the samples taken in the sediment and the chemical preparation used at the sawmill. There was also a similarity between the proportions of metals in the sediment and the solution with metals used at the sawmill. It was there for concluded that the pollution mainly originates from the sawmill. The amount of dioxins was above the guidelines from both USA and Canada for most samples. For the metals, the guideline for arsenic in both USA and Canada was exceeded in all the samples, for copper the guideline from Canada was exceeded in all the samples and two of the samples exceeded the guideline from USA. The chromium amount did not exceed any guidelines in this study. The pollutions appear to be transported outwards towards the ocean and superimposed by sediment deposited later. Further studies to determine the bioavailability of the pollution and to determine further how the pollutions have spread and superimposed in the sediment are necessary.
9

En översiktlig miljöteknisk markundersökning : En fallstudie för att undersöka dioxinförekomst vid en nedlagd sågverksamhet i Lövsele, Västerbottens län

Sundqvist, Elin January 2016 (has links)
Sawmills which conducted dipping operations is a breach where previously used chemicals mean that you generally can expect to find contaminated areas. To investigate contaminated areas the Swedish environmental protection agency developed a method for investigation of polluted areas (MIFO). The purpose of a MIFO analysis is to provide a unified approach and risk classification system for polluted areas. The aim of this thesis it to perform a soil survey according to MIFO phase 2 (general investigations) at the former sawmill in Lövsele, Västerbotten county. The study is based on assumptions about the presence of dioxins in the area, due to the previous use of the wood preservative Ky-5. Dioxins are dangerous substances and are considered poisonous for both humans and the environment. The field study was conducted 30 September 2016 in 8 selected points where the greatest risk to find dioxins were considers to exist after completion of background investigations. 9 samples were the chosen for analysis by ALS Scandinavia AB. The completed analysis shows that pollution levels above the guideline values of both sensitive land use (KM) and less sensitive land use (MKM) were discovered in 7 out of 9 analyzed samples. The MIFO analysis was conducted to answer questions about the pollution hazards, pollution level, distribution conditions and the sensitivity and protection value in the area. The result of the MIFO-analysis is evaluated as class 1, very high risk to human health and the environment. Further studies should therefore be conducted to determine the pollution situation in the area and to provide data for remediation measures to reduce the risk to human health and the environment.
10

Image processing technique to count the number of logs in a timber truck

Shaik, Asif ur Rahman, Yella, Siril, Dougherty, Mark January 2011 (has links)
This paper summarises the results of using image processing technique to get information about the load of timber trucks before their arrival using digital images or geo tagged images. Once the images are captured and sent to sawmill by drivers from forest, we can predict their arrival time using geo tagged coordinates, count the number of (timber) logs piled up in a truck, identify their type and calculate their diameter. With this information we can schedule and prioritise the inflow and unloading of trucks in the light of production schedules and raw material stocks available at the sawmill yard. It is important to keep all the actors in a supply chain integrated coordinated, so that optimal working routines can be reached in the sawmill yard.

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