Demo Abstract: Smart Antennas Made Practical: The SPIDA Way

WISENET (NES)CONE

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM

We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas-phase Master Chemical Mechanism version 3.2 (MCMv3.2), an aerosol dynamics and particle-phase chemistry module (which considers acid-catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion-limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study (1) the evaporation of liquid dioctyl phthalate (DOP) particles, (2) the slow and almost particle-size-independent evaporation of alpha-pinene ozonolysis secondary organic aerosol (SOA) particles, (3) the mass-transfer-limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), and (4) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed alpha-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. In the smog chamber experiments, these salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating alpha-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar-like amorphous-phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if the concentration of low-volatility and viscous oligomerized SOA material at the particle surface increases upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass-transfer-limited uptake of condensable organic compounds onto wall-deposited particles or directly onto the Teflon chamber walls of smog chambers can have a profound influence on the observed SOA formation. During the early stage of the SOA formation the wall-deposited particles and walls themselves serve as an SOA sink from the air to the walls. However, at the end of smog chamber experiments the semi-volatile SOA material may start to evaporate from the chamber walls. With these four model applications, we demonstrate that several poorly quantified processes (i.e. mass transport limitations within the particle phase, oligomerization, heterogeneous oxidation, organic salt formation, and chamber wall effects) can have a substantial influence on the SOA formation, lifetime, chemical and physical particle properties, and their evolution. In order to constrain the uncertainties related to these processes, future experiments are needed in which as many of the influential variables as possible are varied. ADCHAM can be a valuable model tool in the design and analysis of such experiments

BUILDING AND EXPERIMENTALLYEVALUATING A SMART ANTENNA FOR LOWPOWER WIRELESS COMMUNICATION

In wireless communication there is commonly much unnecessarycommunication made in directions not pointing towards the recipient. Normallyomni directional antennas are being used which sends the same amount ofenergy in all directions equally. This waste of energy reduces the lifetime ofbattery powered units and causes more traffic collisions than necessary. Oneway of minimizing this wasted energy and traffic collisions, is to use anothertype of antenna called “smart antenna”. These antennas can use selectableradiation patterns depending on the situation and thus drastically minimize theunnecessary energy waste. Smart antennas also provide the ability to sense thedirection of incoming signals which is favorable for physical layout mappingsuch as orientation.This thesis presents the prototyping of a new type of smart antenna called theSPIDA smart antenna. This antenna is a cheap to produce smart antennadesigned for the 2.4 GHz frequency band. The SPIDA smart antenna can usesixty-four different signal patterns with the control of six separate directionalmodes, amongst these patterns are six single direction patterns, an omnidirectionalsignal pattern and fifty-six combi-direction patterns. The thesispresents complete building instructions, evaluation data and functional driversfor the SPIDA smart antenna

Building and experimentally evaluating a smart antenna for low power wireless communication

In wireless communication there is commonly much unnecessary communication made in directions not pointing towards the recipient. Normally omni directional antennas are being used which sends the same amount of energy in all directions equally. This waste of energy reduces the lifetime of battery powered units and causes more traffic collisions than necessary. One way of minimizing this wasted energy and traffic collisions, is to use another type of antenna called “smart antenna”. These antennas can use selectable radiation patterns depending on the situation and thus drastically minimize the unnecessary energy waste. Smart antennas also provide the ability to sense the direction of incoming signals which is favorable for physical layout mapping such as orientation. This thesis presents the prototyping of a new type of smart antenna called the SPIDA smart antenna. This antenna is a cheap to produce smart antenna designed for the 2.4 GHz frequency band. The SPIDA smart antenna can use sixty-four different signal patterns with the control of six separate directional modes, amongst these patterns are six single direction patterns, an omni-directional signal pattern and fifty-six combi-direction patterns. The thesis presents complete building instructions, evaluation data and functional drivers for the SPIDA smart antenna

Ägarstrukturens påverkan på börsintroduktioners långsiktiga prestation - En jämförande studie av familjeägda vs Private Equity-backade börsnoteringar genomförda under åren 2011-2013

TITEL: Ägarstrukturens påverkan på börsintroduktioners långsiktiga prestation - En jämförande studie av familjeägda vs Private Equity-backade börsnoteringar under åren 2011-2013 SEMINARIEDATUM: 2017-06-01 KURS: FEKH89, Examensarbete i finansiering på kandidatnivå, 15 HP FÖRFATTARE: Erik Will Johansson, Oscar Will Johansson, Kajsa Öström HANDLEDARE: Tore Eriksson NYCKELORD: Börsintroduktion, långsiktig prestation, familjeägande, Private Equity, svenska marknaden SYFTE: Syftet med denna studie är att undersöka och analysera om ägarstrukturer, i form av Private Equity respektive familjeägande, har olika påverkan på den långsiktiga prestationen hos börsintroduktioner genomförda under åren 2011-2013. METOD: Kvantitativ metod med deduktiv ansats vid analys av sekundärdata. Beräkning av långsiktig prestation med abnormal avkastning, BHAR, som utmynnar i en regressionsanalys. TEORETISKA PERSPEKTIV: Studien grundar sig på tidigare forskning om långsiktig prestation och hur olika ägarstrukturer påverkar prestation, samt undersökningar om börsintroduktioners prestation på den svenska och globala marknaden. EMPIRI: Sammanställning av prestationen under tre år efter börsintroduktion för 39 företag listade på First North och Nasdaq OMX Stockholm, jämförs med index OMXSGI. RESULTAT: Studien visar att en viss skillnad i långsiktig prestation förekommer mellan olika ägarstrukturer. Familjeägda företag presterar i genomsnitt bättre än Private-Equity-backade företag. Låg statistisk signifikans kan påvisas.TITLE: The effect of ownership on IPO’s long-run performance - A comparing study of family-owned vs Private Equity-backed IPO’s issued during the period 2011-2013 SEMINAR DATE: 2017-06-01 COURSE: FEKH89, Degree Project in Corporate Finance, Business Administration, Undergraduate level, 15 ECTS AUTHORS: Erik Will Johansson, Oscar Will Johansson, Kajsa Öström ADVISOR: Tore Eriksson KEY WORDS: IPO, long-run performance, family ownership, Private Equity, swedish market PURPOSE: The purpose of this study is to investigate and analyze if the ownership structure, in the form of Private Equity and familyownership, has impact on the long- run performance of IPOs issued during the years 2011-2013. METHODOLOGY: Quantitative method with a deductive approach when analysing secondary data. Calculation of long-run performance using abnormal return, BHAR, that ends with a regression analysis. THEORETICAL PERSPECTIVES: The study has its basis in previous research on long-run performance and how ownership affect performance along with studies of IPO’s performance on the swedish and global market. EMPIRICAL FOUNDATIONS: Compilation of performance three years after issued IPO for 39 companies listed at First North and Nasdaq OMX Stockholm, compared to index OMXGI. CONCLUSIONS: The study shows a slight difference in long-run performance between different types of ownerships. In average, family owned companies perform better than Private Equity-backed companies. Low statistical significance can be found

Biogenic SOA formation through gas-phase oxidation and gas-to-particle partitioning-a comparison between process models of varying complexity

Biogenic volatile organic compounds (BVOCs) emitted by vegetation play an important role for aerosol mass loadings since the oxidation products of these compounds can take part in the formation and growth of secondary organic aerosols (SOA). The concentrations and properties of BVOCs and their oxidation products in the atmosphere are poorly characterized, which leads to high uncertainties in modeled SOA mass and properties. In this study, the formation of SOA has been modeled along an air-mass trajectory over northern European boreal forest using two aerosol dynamics box models where the prediction of the condensable organics from the gas-phase oxidation of BVOC is handled with schemes of varying complexity. The use of box model simulations along an air-mass trajectory allows us to compare, under atmospheric relevant conditions, different model parameterizations and their effect on SOA formation. The result of the study shows that the modeled mass concentration of SOA is highly dependent on the organic oxidation scheme used to predict oxidation products. A near-explicit treatment of organic gas-phase oxidation (Master Chemical Mechanism version 3.2) was compared to oxidation schemes that use the volatility basis set (VBS) approach. The resulting SOA mass modeled with different VBS schemes varies by a factor of about 7 depending on how the first-generation oxidation products are parameterized and how they subsequently age (e.g., how fast the gas-phase oxidation products react with the OH radical, how they respond to temperature changes, and if they are allowed to fragment during the aging process). Since the VBS approach is frequently used in regional and global climate models due to its relatively simple treatment of the oxidation products compared to near-explicit oxidation schemes, a better understanding of the above-mentioned processes is needed. Based on the results of this study, fragmentation should be included in order to obtain a realistic SOA formation. Furthermore, compared to the most commonly used VBS schemes, the near-explicit method produces less-but more oxidized-SOA

Model data for simulation of secondary organic aerosol formation over the boreal forest, link to NetCDF files in zip archive

Secondary organic aerosol particles (SOA) are important climate forcers, especially in otherwise clean environments such as the boreal forest. There are, however, major uncertainties in the mechanisms behind the formation of SOA, and in order to predict the growth and abundance of SOA at different conditions, process-based understanding is needed. In this study, the processes behind new particle formation (NPF) events and subsequent growth of these particles in the northern Europe sub-Arctic forest region are explored with the one-dimensional column trajectory model ADCHEM. The results from the model are compared with particle number size distribution measurements from Pallas Atmosphere-Ecosystem Supersite in Northern Finland. The model was able to reproduce the observed growth of the newly formed particles if a small fraction of the emitted monoterpenes that are oxidized by O3 and OH undergo autoxidation and form highly oxidized multifunctional organic molecules (HOMs) with low or extremely low volatility. The modeled particles originating from the NPF events (diameter < 100 nm) are composed predominantly of HOMs. While the model seems to capture the growth of the newly formed particles between 1.5 and ~ 20 nm in diameter, it underestimated the particle growth between ~ 20 and 80 nm in diameter. Due to the high fraction of HOMs in the particle phase, the oxygen-to-carbon (O : C) atomic ratio of the SOA was nearly 1. This unusually high O : C and the discrepancy between the modeled and observed particle growth might be explained by the fact that the model did not consider any particle-phase reactions involving semi-volatile organic compounds with relatively low O : C. According to the model the phase state of the SOA (assumed either liquid or amorphous solid) had an insignificant effect on the evolution of the particle number size distribution during the NPF events. The results were sensitive to the method used to estimate the vapor pressures of the HOMs. If the HOMs were assumed to be extremely low volatile organic compounds (ELVOCs) or non-volatile the modeled particle growth was substantially higher than when the vapor pressures of the HOMs were estimated based on continuum solvent model calculations using quantum chemical data. Overall, the model was able to capture the main features of the observed formation and growth rates during the studied NPF-events if the HOM mechanism was included