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Using CT to evaluate mediastinal great vein invasion by thymic epithelial tumors: measurement of the interface between the tumor and neighboring structures
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Automatic Scaling in Structure from Motion Photogrammetry for 3D Fragmentation Size Distribution Measurement
Get PDF秋田大学博士（工学）In any mining operation, there are a number of factors that can affect the efficiency of the day-to-day resource extraction process across all of its stages from mine (drilling, blasting, haulage) to mill (mineral processing). As such, it is up to the management, when possible, to monitor these various factors and act accordingly by making modifications to mine planning as well as tweaking its execution. One of such factors, specifically in mining operations that employ explosives and mineral processing, is the fragmentation size distribution of rock after it has been blasted.
Scaling is a critical component of fragmentation size distribution measurement using photogrammetry as it will directly determine the accuracy of the size estimation. In creating a 3D model, extrinsic data such as ground truths are needed to create a properly-scaled reconstruction of the scene. There are several methods that are used to resolve scale in photogrammetry. Most of these methods have the same basic idea in that once the exact distance between at least two different points in a scene is known, a scale factor can be applied to the 3D model. One way to do this is to include an object of known length such as scale bars in the scene. In larger applications such as aerial mapping, GCPs (Ground Control Points) are used, which are marked points of known absolute or relative coordinates.
The study aims to create a system for creating a scaled 3D model without the use of ground truth data such as GCPs (Ground Control Points) for the purpose of improving fragmentation size distribution measurement using positional data such as GNSS (Global Navigation Satellite System)-aided photogrammetry. To achieve this, the study firstly aimed to 1) investigate the effect of camera positional data and constraints on 3D model scaling accuracy; then 2) simultaneously collect image and positional data (e.g., GNSS) from scenes that are to be reconstructed using photogrammetry; then 3) use the positional data in the photogrammetry workflow to scale the resulting 3D model; then 4) observe the effect of increasing the number of datapoints (image + positional data) on the scaling accuracy of the generated 3D model and finally 5) Determine the most effective configuration in data taking and data processing to achieve acceptable scale with the least number of datapoints needed.
A preliminary experiment that was done show results that constraining camera positions to locations, relative or otherwise improves the accuracy of the generated 3D model. With this fundamental idea in mind, the study moved on to larger scale experiments that involved the actual use of GNSS positional data in conjunction with image data in 3D photogrammetry. In these further experiments, results show that the scale error decreases when more images from the same dataset are used. In conclusion two observations have been drawn from the study: firstly, constraining cameras to accurate positions in SfM will result in a properly scaled 3D model; secondly, increasing the number of georeferenced images in SfM will incrementally improve the scaling error of the reconstruction. These results lend credence to the possibility of improving the scaling aspect of 3D fragmentation measurement systems without the use of GCP or manual scales, specifically in surface mines where GNSS data is generally readily available. This shows that monitoring the fragmentation distribution can potentially be performed using just a camera and a GNSS-enabled devices, such as smartphones
The nitric oxide-cyclic guanosine monophosphate pathway inhibits the bladder ATP release in response to a physiological or pathological stimulus
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Combining Economic, Geological and Technical Uncertainties in Mining Projects Valuation Using Real Options Analysis
Get PDF秋田大学博士（工学）The selling of examined metal is the only mining company revenue generator. It implies a certain amount of metal and selling price would grow their revenue. Before mining, the company should estimate the reserves with tremendous uncertainty. In addition, fluctuation of the metal price as economic uncertainty forces the company to deal with an advanced strategy to gain optimum value because profit is very sensitive to the selling price. Nevertheless, the cost of mining operations is unstable due to both local and global economic conditions. Cost instability represents the technical uncertainty of the process that consists of mining and processing-related expenditure.
Geology and mining operations need excessive capital expenditure to run the project. In contrast, finance has to press the expense to guarantee profit. A balance between them is the crucial success of mining. Exploration is necessary to estimate the resource. The estimation is detailed with core drilling at a considerable cost and yielded a certain confidence level of reserves with inherent uncertainty. Sales prices and expenses are commonly assumed in constant or constant growth without compromising their fluctuation. However, project evaluation cannot ignore those uncertainties to get the project value.
A standard method to evaluate a project value, Discounted Cash Flow (DCF), could not adequately account for the future risk. Net Present Value (NPV) as the decision parameter of the DCF method theoretically only generates two decision areas that are accepted and declined. While in reality, management commonly takes no action to wait for a reasonable commodity price, stable cost and ensure the number of reserves by collecting more exploration data. As a result, recent study dedicated to accounting for uncertainty, real options (RO) valuation, adapt financial option theory to be practiced in a real business. On the other hand, uncertainty in reserves is modelled by geostatistics methodology, kriging, and conditional simulation, which captures the spatial variability of the deposits.
There are three approaches in RO methodology: Black Scholes (BS) Valuation, Binomial Lattice (BL) Valuation, and simulation. The complexity of RO in BS and BL approach arises when considering multi uncertainties in project evaluation. On the other hand, simulation approach in RO is not well developed. As a result, RO studies often only consider price as an uncertainty driver. This research combined price, grade and cost uncertainty in a mining project evaluation through the simulation approach, namely Multistage Stratified Stage Aggregation (MSSA), which would be the study's originality. Conditional simulation methods in geostatistics will be utilized to account for grade uncertainty. Thus, the expected reserve and the deviation are incorporated with commodity price and cost uncertainties.
This study demonstrated a project evaluation method covering resource estimation, mine planning, economic evaluation, and uncertainty assessment. The data was collected from PT Timah, Tbk, the most significant world tin producer in 2020, located in Indonesia. The data consisted of drill hole exploration and historical operation costs, while price data was recorded from the S&P 500. Those data were followed by resource estimation using conditional simulation, particularly Sequential Gaussian Simulation, which was run with the GEOVIA Surpac mining program. Mine planning and project evaluation were conducted with the GEOVIA Whittle mining program and converted to a monthly cash flow model. Finally, the uncertainty assessment was done with the real options method, especially MSSA, which utilized java programming language. The originality of the methodology was the development of path generation through java which is an essential step in the MSSA method.
Our research was a pilot method that demonstrated a combination of advances in resource estimation and economic evaluation. The conditional simulation method indicated that each reserve location had its geological uncertainty. Furthermore, Geometric Brownian Model (GBM) was used to make price simulations and get the price uncertainty. Lastly, we utilized the Mean Reverting Process to model cost uncertainty. The three uncertainties represented geological, economic, and technical uncertainties, respectively. MSSA is an alternative method to get project value considering those three uncertainties. A benchmark comparison of the MSSA result with BS and BL approaches resulted in a slight difference.
In summary, we developed a project evaluation methodology that considered geological, economic, and technical uncertainties represented by grade, price and cost, respectively. In our case study, the manager can run the project, but they must ensure the project cost. In addition, the price and geological uncertainties will not be revealed until they decide to mine its reserve; thus, controlling the production and price is essential to guarantee project profitability
Enhancement of energy density of electrochemical capacitors using porous carbon
Get PDF秋田大学博士（工学）Electric double layer capacitors (EDLCs) are superior to other energy storage devices in terms of power density and lifetime. Li-ion capacitor (LIC), which combines the anode of Li ion batteries (LIBs) with the cathode of EDLC, is also a promising energy storage device. LICs can achieve higher energy densities than EDLCs, although its cycle performance is lower than EDLCs. There is a need to increase the energy density of these electrochemical capacitors because it has been one-order lower than that of LIBs. Porous carbons have been used as both the electrodes of EDLCs and as the cathode of LICs, and can be fabricated from a variety of organic materials. This thesis targets on the enhancement of energy density of electrochemical capacitors using porous carbons, as well as new anodic active material of LICs. Activated carbons (ACs) are the active material that can be produced from biomass resources, and various attempts have been made to produce ACs derived from biomass resources. However, there are still many biomass resources that have not been utilized. In Chapter 2, the fabrication of AC derived from unused biomass resources as the electrode active material for high energy density EDLC is described. Next, in Chapter 3, the potential of high-performance AC as the electrode active material of EDLC is described. Finally, in Chapter 4, enhancement of energy density of LIC using high-performance AC cathode and Si-based anode is described. Conclusively, ACs derived from organic wastes were shown to be useful as the electrode active materials. It was also exhibited that the particle size of the high specific surface area AC was an important factor affecting the performance of the EDLC, and the high specific surface area AC with optimal particle size for high energy density EDLCs was obtained. A high energy density LIC was realized by matching the operating capacity of the LIC that combines the above high specific surface area AC cathode and Si anode. Owing to the present study, electrochemical capacitors are expected to be used as energy storage devices in various fields because they can overcome the drawback of low energy density. In other words, they can contribute to the development of sustainable society.
電気⼆重層キャパシタ（EDLC）は、他の蓄電デバイスよりも出⼒密度や寿命の点で優れている。 また、Li イオン電池（LIB）の負極とEDLCの正極を組み合わせたリチウムイオンキャパシタ（LIC） は、有望なエネルギー貯蔵デバイスとして期待されている。LIC は、EDLC よりも⾼いエネルギー 密度を実現できるが、サイクル性能はEDLC よりも低い。これら電気化学キャパシタのエネルギ ー密度は、LIB に⽐べて⼀桁低いため、より⾼いエネルギー密度が求められている。多孔質炭素 は、EDLC の電極やLIC の正極として⽤いられており、様々な有機材料から作製することが可能 である。本論⽂では、多孔質炭素を⽤いた電気化学キャパシタのエネルギー密度の向上と、LIC の 新しいアノード活物質を対象としている。多孔質炭素である活性炭はバイオマス資源から製造可 能な活物質であり、バイオマス資源由来の活性炭の製造は様々な試みがなされている。しかし、 まだ利⽤されていないバイオマス資源が多く存在する。第2 章では、⾼エネルギー密度EDLC の ための電極活物質としての未利⽤バイオマス資源由来活性炭の製造について述べる。次に第3 章 では，⾼性能活性炭のEDLC の電極活物質としての可能性について述べる。最後に第4 章では、 LIC の⾼エネルギー密度化について述べる。結論として、有機廃棄物由来の多孔質炭素は、電極 活物質として有⽤であることが⽰された。また，⾼⽐表⾯積活性炭の粒⼦径がEDLC の性能に影 響を与える重要な因⼦であることが⽰され，⾼エネルギー密度EDLC に最適な粒⼦径の⾼⽐表⾯ 積活性炭が得られた。その⾼⽐表⾯積活性炭正極とSi 負極を組み合わせたLIC の動作容量を⼀致 させることで、⾼エネルギー密度LIC を実現した。本研究により、電気化学キャパシタは、エネ ルギー密度が低いという⽋点を克服できるため、様々な分野でのエネルギー貯蔵デバイスとして の利⽤が期待でき、持続可能な社会の発展に寄与する
鉱山操業における生産性と安全性向上のための坑内掘鉱山内モニタリングシステムに関する研究
Get PDF秋田大学博士（工学）As modern society becomes more sophisticated, the consumption of metal resources has become essential. There is a worldwide need for technologies to safely and efficiently mine metal resources. In addition, as the deposits to be mined are becoming deeper and lower grade year by year, there is an urgent need to increase minable reserves through technological innovation. Mining science is a discipline and technological system that integrates geology, rock mechanics, civil engineering, disaster prevention engineering, and mechanical engineering, which has developed in its own unique way. On the other hand, ICT (artificial intelligence, big data, data mining, etc.), has shown remarkable development. In the future, smart mining through ICT applications in mining science is expected to lead resource development.
Underground mines are generally located deep underground, mining companies operate under hazards such as poor lighting, confined spaces, rockfall, poor ventilation, wetness, limited communication, and structural complexity. In this context, safety and productivity in underground operations are of primary concern to companies. To solve these problems, various monitoring methods have been proposed to understand the underground environment. By installing a number of sensors in underground mines and acquiring measurement factors such as temperature, humidity, and gas concentration, it is possible to monitor the underground environment.
For this reason, this study develops an underground mine monitoring system to improve productivity and safety in mining operations. The underground mine monitoring system proposed in this study is divided into two parts: the sensing part, which is a differential measurement of in-situ stress and strain, and the data transmission part, which uses ad hoc communication. Multiple sensor units are installed in the mine, and the accumulated data is collected by ad hoc communication when a miner’s smartphone approaches communication area. Next, the data transfer range is pseudo-expanded by passing data through the movements of the miners. Finally, data is transmitted to an office with a communication infrastructure by either miner or going above ground. The data sent to the office on the ground can be checked and edited anywhere in the world via the cloud. In the sensing part, the developed sensor unit is buried in a blank hole after stress release to determine the difference in stress applied from the bedrock from the strain gauge values. In this case, it is necessary to detect the orientation of the sensor unit in order to estimate how much stress is applied and from which direction.
In the communication part, among WSNs (Wireless Sensor Networks), which are scalable and suitable for underground mines, pseudo communication range expansion by miner’s movement, Wi-Fi Ad Hoc communication (Wi-Fi Ad Hoc and Wi-Fi Direct) and communication obstacles can be avoided. Focusing on power line communications, we implemented and verified an ad hoc wireless communication system by testing communications from a data logger to a smartphone held by a miner. Based on the results obtained from each research item, the combination of sensor units and ad hoc communication is expected to make it possible to identify signs of rock deformation at a lower cost than previously thought possible, and to dramatically improve safety in the mine
