Michigan Technological University

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    Vol 2 No 3; 8 February 1964. Land of the Sandman.https://digitalcommons.mtu.edu/wintercarnival/1000/thumbnail.jp


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    This thesis develops high performance real-time signal processing modules for direction of arrival (DOA) estimation for localization systems. It proposes highly parallel algorithms for performing subspace decomposition and polynomial rooting, which are otherwise traditionally implemented using sequential algorithms. The proposed algorithms address the emerging need for real-time localization for a wide range of applications. As the antenna array size increases, the complexity of signal processing algorithms increases, making it increasingly difficult to satisfy the real-time constraints. This thesis addresses real-time implementation by proposing parallel algorithms, that maintain considerable improvement over traditional algorithms, especially for systems with larger number of antenna array elements. Singular value decomposition (SVD) and polynomial rooting are two computationally complex steps and act as the bottleneck to achieving real-time performance. The proposed algorithms are suitable for implementation on field programmable gated arrays (FPGAs), single instruction multiple data (SIMD) hardware or application specific integrated chips (ASICs), which offer large number of processing elements that can be exploited for parallel processing. The designs proposed in this thesis are modular, easily expandable and easy to implement. Firstly, this thesis proposes a fast converging SVD algorithm. The proposed method reduces the number of iterations it takes to converge to correct singular values, thus achieving closer to real-time performance. A general algorithm and a modular system design are provided making it easy for designers to replicate and extend the design to larger matrix sizes. Moreover, the method is highly parallel, which can be exploited in various hardware platforms mentioned earlier. A fixed point implementation of proposed SVD algorithm is presented. The FPGA design is pipelined to the maximum extent to increase the maximum achievable frequency of operation. The system was developed with the objective of achieving high throughput. Various modern cores available in FPGAs were used to maximize the performance and details of these modules are presented in detail. Finally, a parallel polynomial rooting technique based on Newton’s method applicable exclusively to root-MUSIC polynomials is proposed. Unique characteristics of root-MUSIC polynomial’s complex dynamics were exploited to derive this polynomial rooting method. The technique exhibits parallelism and converges to the desired root within fixed number of iterations, making this suitable for polynomial rooting of large degree polynomials. We believe this is the first time that complex dynamics of root-MUSIC polynomial were analyzed to propose an algorithm. In all, the thesis addresses two major bottlenecks in a direction of arrival estimation system, by providing simple, high throughput, parallel algorithms


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    Important food crops like rice are constantly exposed to various stresses that can have devastating effect on their survival and productivity. Being sessile, these highly evolved organisms have developed elaborate molecular machineries to sense a mixture of stress signals and elicit a precise response to minimize the damage. However, recent discoveries revealed that the interplay of these stress regulatory and signaling molecules is highly complex and remains largely unknown. In this work, we conducted large scale analysis of differential gene expression using advanced computational methods to dissect regulation of stress response which is at the heart of all molecular changes leading to the observed phenotypic susceptibility. One of the most important stress conditions in terms of loss of productivity is drought. We performed genomic and proteomic analysis of epigenetic and miRNA mechanisms in regulation of drought responsive genes in rice and found subsets of genes with striking properties. Overexpressed genesets included higher number of epigenetic marks, miRNA targets and transcription factors which regulate drought tolerance. On the other hand, underexpressed genesets were poor in above features but were rich in number of metabolic genes with multiple co-expression partners contributing majorly towards drought resistance. Identification and characterization of the patterns exhibited by differentially expressed genes hold key to uncover the synergistic and antagonistic components of the cross talk between stress response mechanisms. We performed meta-analysis on drought and bacterial stresses in rice and Arabidopsis, and identified hundreds of shared genes. We found high level of conservation of gene expression between these stresses. Weighted co-expression network analysis detected two tight clusters of genes made up of master transcription factors and signaling genes showing strikingly opposite expression status. To comprehensively identify the shared stress responsive genes between multiple abiotic and biotic stresses in rice, we performed meta-analyses of microarray studies from seven different abiotic and six biotic stresses separately and found more than thirteen hundred shared stress responsive genes. Various machine learning techniques utilizing these genes classified the stresses into two major classes\u27 namely abiotic and biotic stresses and multiple classes of individual stresses with high accuracy and identified the top genes showing distinct patterns of expression. Functional enrichment and co-expression network analysis revealed the different roles of plant hormones, transcription factors in conserved and non-conserved genesets in regulation of stress response


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    Commercial aspen (Populus spp.) forests of the Great Lakes region are primarily managed for timber products such as pulp fiber and panel board, but logging residues (topwood and non-merchantable bolewood) are potentially important for utilization in the bioenergy market. In some regions, pulp and paper mills already utilize residues as fuel in combustion for heat and electricity, and progressive energy policies will likely cause an increase in biomass feedstock demand. The effects of removing residues, which have a comparatively high concentration of macronutrients, is poorly understood when evaluating long-term site productivity, future timber yields, plant diversity, stand dynamics, and consequently, appropriate silviculture. These practices were evaluated throughout the western Upper Peninsula of Michigan using forest inventory data from harvested stands over the last 45 years. Assessment provided a framework of ecosystem carbon patterns across stand rotation, and comparisons reflected moderate losses in residue-bound carbon pools when captured. However, residue loads exceeded those recommended by established residue retention guidelines even in stands where residues were recovered for bioenergy. Soil nutrient pools exhibited declines under residue removal treatments on coarse textured soils. Aboveground biomass and timber yields did not vary according to residue treatment, and development of the aspen cohort was similar across all soil types, regardless of nutrient levels, an unexpected result. Stand dynamics varied by soil productivity class in the late stages of stand rotation, and imply that encouragement of non-crop trees for ecological purposes does not affect yields of the aspen resource. Predictions based upon historical growth and yield models showed mixed levels of accuracy when compared to observations. Analyses of vegetation communities and multivariate ordination methods revealed temporal patterns in species richness and increased heterogeneity under residue removal treatments. A spatially explicit sampling design was utilized to examine advances in harvesting technology on variance in stand level regeneration, soil nutrients, and residue estimates. Operator and equipment induced patterns in harvesting activity were found to increase residue loads with a concomitant decline in stem density and height growth across a large portion of the regenerating stand. Collectively, these findings suggest that residue removal results in a minor decline in aboveground C stocks, and coarse textured soils may be susceptible to reductions in forest soil nutrient pools. Further, variations in growing conditions at the forest floor due to high residue loads may adversely affect understory vegetation communities. Finally, harvesting equipment, cut-block layout, and residue distribution can influence stand regeneration patterns, and warrants consideration in harvest and silvicultural planning

    Limitations of Nuclear Power as a Sustainable Energy Source

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    This paper provides a review and analysis of the challenges that nuclear power must overcome in order to be considered sustainable. The results make it clear that not only do innovative technical solutions need to be generated for the fundamental inherent environmental burdens of nuclear energy technology, but the nuclear industry must also address difficult issues of equity both in the present and for future generations. The results show that if the concept of just sustainability is applied to the nuclear energy sector a global large-scale sustainable nuclear energy system to replace fossil fuel combustion requires the following: (i) a radical improvement in greenhouse gas emissions intensity by improved technology and efficiency through the entire life cycle to prevent energy cannibalism during rapid growth; (ii) the elimination of nuclear insecurity to reduce the risks associated with nuclear power so that the free market can indemnify it without substantial public nuclear energy insurance subsidies; (iii) the elimination of radioactive waste at the end of life and minimization of environmental impact during mining and operations; and (iv) the nuclear industry must regain public trust or face obsolescence as a swarm of renewable energy technologies quickly improve both technical and economic performance


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    Titanium and its alloys are typically used for fabrication of dental and orthopedic implants as they possess various desirable properties including biocompatibility and corrosion resistance. In spite of such benefits, titanium implants show lack of osseointegration after surgery in minor cases. The objective of this research has been to modify the surface of titanium alloy for medical applications through increasing surface hydrophilicity and drug loading. Primarily, anodization method is employed for fabrication of nanotubes on titanium surface to act as anchoring cite for cells. Considering the key role of surface hydrophilicity on cellular attachment to the surface and subsequent biological behavior of attached cells, the fabrication condition of nanotubes during anodization and following heat treatment is optimized. It is shown that anodization voltage, anodization duration and heat treatment temperature and duration can be controlled to fabricate a nanotubular surface that maintains its hydrophilicity over a long period of time. In order to verify the role of surface morphology on obtained characteristics, smooth, anodized-smooth, rough and anodized-rough surfaces are explored. The results show that anodized-smooth and anodized-rough surfaces show higher hydrophilicity than non anodized surfaces. Hydrophilic nanotubes not only promote cell adsorption; but also increase absorption of aqueous drug solution. Consequently, nanotubes are successfully loaded with drug and act as nano drug reservoirs that are potential to deliver the loaded drug locally after surgery. It is shown that dimension of nanotubes can affect rate of drug release. In fact the results indicate that nanotubes with higher aspect ratio (ratio of length to diameter) prolong drug release. A novel method for fabrication of naotubes was investigated which suggests a new way for controlling length of nanotubes. It is shown that heat treatment of the substrate prior to anodization affects length of nanotubes obtained eventually after anodization. In fact, the results show that anatase crystalline structure affects mechanism of formation of nanotubes to form longer nanotubes. Finally, it is demonstrated that corrosion resistance of heat treated nanotubular surface is higher than either heat treated surface or nanotubular surface alone


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    The study aims at identifying opportunities to implement Low Impact Development (LID) Best Management Practices (BMPs) for stormwater management, in the District of Lámud, Perú. Other studies have noted the importance of appropriate stormwater management as part of urban development in developing countries. Environmental, economic and social aspects were analyzed to identify the most appropriate case. Stormwater Management Model (SWMM) 5.1, was used to obtain runoff results. Ten case scenarios were set up with LID BMP combinations of infiltration trenches, vegetated swales, and retention ponds. Water Environment Research Foundation (WERF) life cost models were used as a reference to calculate initial and maintenance costs. A Cost Benefit Ratio (CBR) was developed to identify the most cost effective case. Data on land use was collected and a Maintenance Probability Factor (MPF) developed to identify the likelihood of maintenance. Case 7 was recommend as it optimizes both CBR and MPF

    Cell culture method and apparatus for mechanically stimulating cells

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    A cell culture assembly and a method for culturing cells that provide mechanical stimulation to cells. The cell culture assembly can include a flow chamber positioned in a fluid path and a support comprising cells positioned within the flow chamber to expose the cells to the fluid path. The cell culture assembly can further include a means for producing a steady flow of fluid in the fluid path, and a means for producing an oscillatory flow of fluid in the fluid path simultaneously with producing the steady flow of fluid in the fluid path to mechanically stimulate the cells. The method can include transporting fluid in the fluid path at a substantially steady flow rate, and transporting fluid in the fluid path at a substantially oscillatory flow rate simultaneously with transporting fluid in the fluid path at a substantially steady flow rate.https://digitalcommons.mtu.edu/patents/1023/thumbnail.jp

    High strength alumina and process for producing same

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    A vacuum hot pressed alumina material having small, isometric grains; a uniform distribution thereof; relatively low, predominantly transgranular porosity; and a density approaching the theoretical density of pure alumina produced by vacuum hot pressing alumina powder which contains at least 98.0% alumina, is substantially free of any sintering aids or any other additives, and has a median particle size less than about 3 microns, in a vacuum hot press operated at a temperature of at least about 1350° C. and a pressure of at least 28 MPa (3500 PSI) for a sintering period of at least 1.5 hours. The vacuum hot pressed alumina material also has compressive strength, flexural strength, impact strength, and wear resistance superior to that for most conventional sintered alumina materials.https://digitalcommons.mtu.edu/patents/1075/thumbnail.jp
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