Phenolics of the Inner Bark of Silver Birch: Characterization and Intraspecific Variation

This thesis describes work related to the in-depth characterization of the phenolic compounds of silver birch (Betula pendula) inner bark. Phenolic compounds are the most ubiquitous class of plant secondary compounds. The unifying feature of this structurally diverse group is an aromatic ring containing at least one hydroxyl group. Due to the structural diversity, phenolics have various roles in the plant defense against biotic and abiotic stresses. In addition, they can confer several health-promoting properties to humans. Furthermore, the structural diversity of this class of compounds causes challenges for their analysis. The study species in the present work, silver birch, is economically the most important hard wood species in northern Europe. Its inner bark contains a high level of phenolic compounds and it has shown one of the strongest antioxidant activities among 92 Finnish plant materials. The literature review surveys the diversity and organ specific distribution of phenolic compounds in silver birch as well as the proposed ecological functions of phenolic compounds in nature. In addition, the basis for the characterization of phenolics by mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and circular dichroism spectroscopy (CD) are reviewed. The objective of the experimental work was to extract, purify, characterize, and quantify the inner bark phenolic compounds. Overall 36 compounds were characterized by MS and ultraviolet spectroscopy (UV). 24 compounds were isolated and their structures confirmed by NMR and CD spectroscopy. Five novel natural compounds were identified. Special emphasis was placed on the establishment of a method for the characterization of proanthocyanidins (PAs). Hydrophilic interaction liquid chromatography (HILIC) was utilized because of its high resolution power and predictable elution order of oligomeric and polymeric PAs according to an increasing degree of polymerization. The combination of HILIC and high-resolution MS detection allowed the identification of procyanidin (PC) polymers up to the degree of polymerization of 22. In addition, a series of oligomeric and polymeric PC monoxylosides were observed for the first time in nature. Season and genotype influenced the quantities of the main inner bark phenolics, yet qualitative differences were not observed. However, manual wounding of the inner bark induced the production of ellagitannins (ETs) in the wounded tissues, i.e. callus. Since ETs were not detected in the intact inner bark, this finding may reflect the capacity of silver birch to exploit ellagitannins in its defense.

Conical aluminum can

The current beverage (cylindrical shape) cans are stacked on each other after production, thus consuming a lot of space. Indirectly, this could result to high carbon emission during transportation. The problem is how to minimize the carbon emission based on different contradicting viewpoints. It was suggested that a conical shape of "the beverage can" could be a solution for the space optimization of empty beverage can transportation, thus creating the title for this research “Conical aluminum can”. They would be stacked inside each other before filling. This was based on design for sustainability and the consumer perspective and willingness toward sustainability. However, it was noticed that the industry is unwilling to incorporate this change.

Simulating the dynamics of silver market using computational market dynamics

Traditional econometric approaches in modeling the dynamics of equity and commodity markets, have, made great progress in the past decades. However, they assume rationality among the economic agents and and do not capture the dynamics that produce extreme events (black swans), due to deviation from the rationality assumption. The purpose of this study is to simulate the dynamics of silver markets by using the novel computational market dynamics approach. To this end, the daily data from the period of 1st March 2000 to 1st March 2013 of closing prices of spot silver prices has been simulated with the Jabłonska-Capasso-Morale(JCM) model. The Maximum Likelihood approach has been employed to calibrate the acquired data with JCM. Statistical analysis of the simulated series with respect to the actual one has been conducted to evaluate model performance. The model captures the animal spirits dynamics present in the data under evaluation well.

Replacing Copper with New Carbon Nanomaterials in Electrical Machine Windings

Electrical machines have significant improvement potential. Nevertheless, the field is characterized by incremental innovations. Admittedly, steady improvement has been achieved, but no breakthrough development. Radical development in the field would require the introduction of new elements, such that may change the whole electrical machine industry system. Recent technological advancements in nanomaterials have opened up new horizons for the macroscopic application of carbon nanotube (CNT) fibres. With values of 100 MS/m measured on individual CNTs, CNT fibre materials hold promise for conductivities far beyond those of metals. Highly conductive, lightweight and strong CNT yarn is finally within reach; it could replace copper as a potentially better winding material. Although not yet providing low resistivity, the newest CNT yarn offers attractive perspectives for accelerated efficiency improvement of electrical machines. In this article, the potential for using new CNT materials to replace copper in machine windings is introduced. It does so, firstly, by describing the environment for a change that could revolutionize the industry and, secondly, by presenting the breakthrough results of a prototype construction. In the test motor, which is to our knowledge the first in its kind, the presently most electrically conductive carbon nanotube yarn replaces usual copper in the windings.

Hitsatun alumiinirakenteen suunnittelu

Alumiiniseosten käyttö konstruktiomateriaalina lisääntyy johtuen sen lukuisista variaatioista lujuuden ja muovattavuuden suhteen. Alumiinin keveys on merkittävä kilpailuetu teräkseen nähden. Alumiiniseosten hitsattavuus on parantunut hitsausmenetelmien kehittyessä. Uusilla menetelmillä lämmöntuontia hallitaan paremmin, kuten myös alumiinin huokoisuutta sekä lujuuden laskua hitsauksen yhteydessä. Tässä diplomityössä tutkitaan alumiinin metallurgiaa, hitsausmenetelmiä, sekä alumiinin ja teräksen sekaliitoksen toteutusta. Tutkimuksella pyritään tekemään hitsatun alumiinirakenteen suunnittelua ymmärrettävämmäksi. SFS-EN standardit antavat perustuksen alumiinirakenteen suunnittelulle. Tässä diplomityössä tehdään suunnitteluesimerkki hitsatun alumiinirakenteen hitsien suunnittelusta. Suunnitteluesimerkissä tutkitaan alumiiniseoksen lujuuden laskua hitsattaessa, ja etsitään standardien antamia ratkaisuja toimivan hitsatun rakenteen toteuttamiseksi.