Search results for "rake"
showing 10 items of 866 documents
Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2”
2015
Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4 N]O2 CCH3 and therefore not representative of the bulk powder from the synthesis.
The role of oxidation treatments before and after CVD synthesis of graphene on copper catalytic surface
2021
Graphene is a sheet of honeycomb bonded carbon, that is only one atom thick. Aside from its remarkable strength, graphene has great conducting and photochemical prop erties. Due to its unique properties, it can be used as viable option for rare metals in circuits and in new type of measuring components. To express these properties at their best, graphene should be single crystal and as clean as possible. In this bachelor thesis, different treatment options for catalytic metal surface for graphene synthesis are studied in chemical vapor deposition growth. Different options to treat the catalytic metal layer were studied, such as changes in gas compositions in annealing process, electropolish…
Use of nanostructures as oxygen carriers in chemical looping combustion
2013
The usage of fossils fuels has increased carbon dioxide emissions, and the carbon dioxide is responsible for global warming and sea level rising. One of the most promising ways of carbon capturing from the power plants is chemical looping combustion (CLC). CLC is based on the alternating oxidation and reduction reactions on the air and fuel reactors. Oxygen and energy needed for combustion between the reactors is transferred by an oxygen carrier. Oxygen carrier is usually made of metal or metal oxide. One big hindrance towards commercial use of CLC is slow reaction kinetics of oxygen carriers. One possible solution for the problem is to replace the conventional carriers by nanoscale oxygen …
Approximate modeling of spherical membranes
2010
Spherical symmetry is ubiquitous in nature. It is therefore unfortunate that simulation of spherical systems is so hard and require complete spheres with millions of interacting particles. Here, we introduce a method to model spherical systems using revised periodic boundary conditions adapted to spherical symmetry. Method reduces computational costs by orders of magnitude, and is applicable for both solid and liquid membranes, provided the curvature is sufficiently small. We demonstrate the method by calculating the bending and Gaussian curvature moduli of single-layer and multilayer graphene. The method works with any interaction (ab initio, classical interactions), with any approach (mol…
Efficient approach for simulating distorted materials
2010
The operation principles of nanoscale devices are based upon both electronic and mechanical properties of materials. Because these properties can be coupled, they need to be investigated simultaneously. At this moment, however, the electronic structure calculations with custom-made long-range mechanical distortions are impossible, or expensive at best. Here we present a unified formalism to solve exactly the electronic structures of nanomaterials with versatile distortions. We illustrate the formalism by investigating twisted armchair graphene nanoribbons with the least possible number of atoms. Apart from enabling versatile material distortions, the formalism is capable of reducing computa…
Hirsirakentamisen teollistuminen : pro gradu -tutkimus teollistumisen vaikutuksista työn tehokkuuteen hirsirakentamisessa : tapaus Honkarakenne Oyj
2011
Tutkin työssäni hirsirakentamisen teollistumisen mahdollisia motiiveja ja seurauksia. Kun puhutaan hirsitalosta, nousee monien mieleen käsityönä veistetty punainen tupa. Nykyään kuitenkin suurin osa Suomessa rakennetuista hirsitaloista on teollisesti valmistettuja. Tutkimukseni fokus on teollistumiskehityksessä ja teollistumisen vaikutuksissa työn tehokkuuteen. Tapaustutkimuksen kohteena on Honkarakenne Oyj, joka oli ensimmäisiä hirsirakentamista teollistaneista yrityksistä, ja kasvoi suurimmaksi teolliseksi valmistajaksi. Lähtöoletukseni oli, että teollistuminen oli tietoista työn tehostamista. Tutkimuksen aluksi määrittelen tarkastelutavaksi seinäneliöt. Tuotantolukuja ja työläisten määri…
Elämää ja aistimuksia vanhassa hirsitalossa : kokemuksellinen näkökulma eräästä asuintavasta
2013
Pro gradu -tutkielmassani tutkin vanhojen hirsitalojen voimakkaan aistimaailman vaikutusta asukkaan ja hänen kotinsa suhteessa. En keskity analyysissani aistimiseen ruumiillisena kokemuksena, vaan painotan aistimusten merkityksellisyyttä. Kiinnitän huomioni etenkin vanhojen hirsitalojen funktionaalisiin rajoitteisiin sekä historian merkkeihin. Tutkielmani liittyy pitkään monitieteiseen rakennustutkimuksen tutkimusperinteeseen. Tutkimusmetodini on etnografinen. Lisäksi hyödynnän fenomenologista filosofian perinnettä innoittajana tutkimuskysymysten suhteen, mutta myös analyyttisena työkaluna. Aineistonani käytän tutkielmassani seitsemää haastattelua, joihin on minun lisäkseni ottanut osaa yhd…
Finnish-American architecture and architects in Northern and Eastern parts of the United States of America 1850-1950 from rural tradition to urban id…
2008
Sanoma, lähettäjä, kulttuuri : lehdistöhistorian tutkimustraditiot Suomessa ja median rakennemuutos
2009
Domestic dexterity and cultural policy : the idea of cottage industry and historical experience in Finland from the great famine to the reconstructio…
2016
The concept of cottage industry (kotiteollisuus) referred especially to rural craft practices. For the promotion of cottage industries, a state administrative organ and a network of cottage industry associations and schools were established. A sphere developed and monitored by specialists, cottage industry policies were planned as official committee work. However, the matter was usually addressed as ‘the idea of cottage industry’ (kotiteollisuusaate). In this study, the historical idea of cottage industry and its cultural and political backgrounds are analysed. The starting point of the investigation is in the post-WWII Cottage Industry Production Committee, but from its years of activity, …