Crystallization of triethyl-citrate-plasticized poly(lactic acid) induced by chitin nanocrystals

The aim of this study was to gain a better understanding of the crystallization behavior of triethyl-citrate-plasticized poly(lactic acid) (PLA–TEC) in the presence of chitin nanocrystals (ChNCs). The isothermal crystallization behavior of PLA–TEC was studied by polarized optical microscopy, scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction (XRD). Interestingly, the addition of just 1 wt % ChNCs in PLA–TEC increased the crystallization rate in the temperature range of 135–125 °C. The microscopy studies confirmed the presence of at least three distinct types of spherulites: negative, neutral, and ring banded. The ChNCs also increased the degree of crystallinity up to 32%, even at a fast cooling rate of 25¿°C min-1. The XRD studies further revealed the nucleation effect induced by the addition of ChNCs and thus explained the faster crystallization rate. To conclude, the addition of a small amount (1 wt %) of ChNC to plasticized PLA significantly affected its nucleation, crystal size, and crystallization speed; therefore, the proposed route can be considered suitable for improving the crystallization behavior of PLA.Peer ReviewedPostprint (author's final draft

Avaruustutkimusta ja politiikkaa

Ilkka Seppinen: Suomalaisen avaruustutkimuksen historia Euroopan Avaruusjärjestön jäsenyyteen asti. Yliopistopaino 2004. 366 s. COSPARin (Committee on Space Research) Suomen kansalliskomitean vuoden 2004 kesäkuussa vietetyn 40-vuotisjuhlan kunniaksi Suomen avaruustutkimus sai ensimmäisen historiansa, kirjoittajanaan Helsingin yliopiston poliittisen historian dosentti Ilkka Seppinen. Hän on saanut laajasta lähdemateriaalistaan kokoon varsin kattavan teoksen, ja teoksen painoasu on tyylikäs. Lähemmällä syventymisellä kirjasta löytää tosin myös yhtä ja toista huomautettavaa

Sähköisen rahtikirjamallin luominen metallien jalostusketjuun

Työn aiheena oli sähköisen rahtikirjamallin luominen metallien jalostusketjuun. Työn tarkoituksena oli selvittää metallien jalostusketjuun sopiva malli, haastattelemalla kuljetusketjun osapuolia, sekä perehtymällä jo olemassa oleviin malleihin. Työssä keskitytään rikasteiden kuljetukseen Mäntyluodon satamasta Harjavaltaan, sekä kuparianodien kuljetukseen Harjavallan tehtaalta jatkojalostuksen Poriin. Näihin kuljetuksiin käytetään rautateitä. Sähköisten palvelujen käyttö logistiikassa on tällä hetkellä vielä vähäistä, verrattuna esimerkiksi muihin pohjoismaihin. Aiheeseen liittyvä kirjamateriaali liittyy lähinnä sähköisiin tiedonsiirtomuotoihin, eikä varsinaisesta aiheesta ole juuri olemassa kirjamateriaalia. Tiedon keruu tapahtui siis pääasiassa netistä. Koska sähköiset rahtikirjat ja siihen liittyvä tiedonsiirto eivät ole kovin vanhoja asioita, on työssä pyritty pitämään siihen liittyvät lähteen mahdollisimman uusina. Työ aloitettiin tutkimalla kuljetusketjun nykyistä tilannetta tiedonsiirron osalta, tutustumalla itse kuljetusketjuun, sekä esittelemällä yritykset jotka ovat kuljetusketjussa mukana. Tiedon keruu tapahtui haastatteluin. Teoriaosuudessa selvitettiin tiedonsiirron nykytilannetta logistiikassa, sekä siinä käytettäviä apuvälineitä, kuten viivakoodia. Myös olemassa oleviin rahtikirjamalleihin perehdyttiin teoriaosuudessa. Haastatteluihin perustuen työn lopussa on selvitys kuljetusketjun tämän hetkisistä ongelmista tiedonsiirtoon liittyen, sekä jokaisen osapuolen tarpeet rahtikirjan suhteen. Olemassa olevien mallien tutustumisen ja ongelmista tehdyn yhteenvedon jälkeen, työn lopussa on esitetty rikasteiden ja anodien kuljetuksiin haastatteluihin ja teoriaan perustuvat vaihtoehdot sähköisestä rahtikirjasta.The theme of this thesis was creating digital waybill system into metal processing chain. The main purpose of the study was to find best digital waybill system for transporting concentrates and anodes. Concentrates are transported by train from Mäntyluoto to Harjavalta and anodes are transported from Harjavalta to Pori. Compared to the other Nordic Countries in Finland electric services in logistics are low. Digital waybills are not very common used and that’s why it is very difficult to find written material about it. There is not available written material about digital waybills, only available is electric data transferring. Main objective in this thesis was to keep sources less than five years old. In the theoretical part of the thesis is studied the metal processing chain where digital waybill is needed. After that is presented companies which are in this chain and there is also studied existing data transfer systems in logistics and instruments like bar codes. Based on interviewing persons from companies there are presented problems about the waybill which are used now. Based on theoretical part of the thesis and interviews it was made report about problems in metal processing chain and also about requirement of digital waybill of com-panies. As a result of this thesis a suggestion of digital waybill system into metal processing chain

Production of bioactive phenolic compounds by berry cell cultures

The production of phenolic compounds by berry cell cultures of strawberry (Fragaria x ananassa) was studied and the biosynthesis of phenolic compounds was stimulated by elicitation

Time-Division Multiplexing Architecture for Hybrid Filter Bank A/D converters

International audienceIn this paper, a new Hybrid Filter Bank (HFB) architecture called Time-Division Multiplexing (TDM) is proposed for HFB-based A/D Converters (ADC). The TDM HFB architecture is firstly extracted considering the TDM components of analog input as new input vector. The TDM HFB-based ADC is then simulated using simply-realizable analysis filters to approve the mathematical formulation of the TDM model. At last, the output resolutions of TDM and classical HFB-based ADC are compared considering practical analog filters including realization errors. It is shown that the TDM architecture is less sensitive to the realization errors than the classical HFB. Besides, the TDM HFB can exploit a blind technique to correct the realization errors in opposite to the classical HFB case

Emotional Dimensions in Integrated Care for People with Multiple Complex Problems

Cross-boundary collaboration, both multiprofessional and interorganizational, is needed when providing integrated care for people with multiple problems, who need services at the same time from diverse care providers. Multiple problems of clients also pose extra challenges for interaction between care professionals and clients. Emotional dynamics are always present in everyday interaction between human beings, but seldom explicitly addressed in research on integrated care. The aim of this reflective paper is to illustrate the emotional dimensions of integrated care in light of the experiences of care professionals in the context of care for people with multiple complex problems. The paper draws on a Finnish study on integrated care reflecting its findings from the perspective of emotional labor. The difficult life situations of people with multiple complex problems form an emotional burden, which is mirrored in the interaction between clients and professionals and affects relational dynamics among professionals. Professionals' fear of emotions and the different feeling rules' of care professions and sectors pose extra challenges to professionals' collaboration in this emotionally loaded context. Alongside the structural and functional aspects of integrated care, it is important that emotions embedded in everyday cross-boundary collaboration are recognized and taken into account in order to ensure the success of integrated care.Peer reviewe

Sensitivity of hybrid filter banks A/D converters to analog realization errors and finite word length

This paper studies the sensitivity of hybrid filter banks (HFB) to analog inaccuracies and finite word implementation. It is shown that very small errors affecting very simple analog structures have a dramatic influence on the performances of the HFB. The influence of the quantization of digital filter coefficients is also studied. A theoretical limit for the error introduced by the quantization of digital filter coefficients is derived

Comparative study on the properties of carbon prepared from different lignin resources

Bio-based carbon particles were produced from different technical lignins, including Kraft lignin, soda lignin, lignoboost and hydrolysis lignin, with different carbonization temperatures (1000 °C and 1400 °C). The structure, morphology, electrical conductivity, and electrochemical performance of the obtained carbon particles were systematically analyzed. The results demonstrate that the lignin resources and carbonization processes have significant impact on the structure and properties of the carbon particles. Kraft lignin carbonized up to 1400 °C gives the highest BET surface area (646 m2 g-1), which makes it a good candidate for making supercapacitors electrodes and a capacitance of 97.2 F g-1 has been obtained with an energy density of 48.6 Wh kg-1 at a power density of 180 W kg-1 at current density of 0.1 A g-1. Soda lignin carbonized up to 1400 °C has showed somewhat graphite like structure and provided highest electrical conductivity of 335 S m-1. These conductive carbon particles can be utilized as reinforcements in composites or can be used for producing electromagnetic interference shielding materials (EMI shielding materials)

Digital estimation of analog imperfections using blind equalization

International audienceThe analog electronic circuits are always subject to some imperfections. Analog imperfections cause deviations from nominal values of electronic elements. In the case of Linear Time-Invariant (LTI) circuits, the coefficients of the transfer function include some deviations from related typical values leading to the differences between the typical (i.e. design) and the actual transfer functions. In this paper, the analog imperfections are digitally estimated using only the output samples, without any access to the input signal nor to the analog system (blind method). Super Exponential Algorithm (SEA) is used as the blind equalization technique, since it provides rapid convergence. The only assumption is that the input is a non-Gaussian independent and identically distributed (i.i.d.) signal. Using this algorithm, the effects of analog imperfections in the analog circuits can be digitally estimated and possibly compensated without any dependance on the types and the sources of the analog imperfections. It provides the possibility to have an online compensation of the imperfections (realization errors, drifts, etc.). The analog imperfections have been estimated with a precision of §0:2% and §1:3% for the exemplary RC and RLC circuits respectively

Extended frequency-band-decomposition sigma–delta A/D converter

Parallelism can be used to increase the bandwidths of ADC converters based on sigma–delta modulators. Each modulator converts a part of the input signal band and is followed by a digital filter. Unfortunately, solutions using bandpass sigma–delta modulators are very sensitive to the position of the modulators' central frequencies. This paper shows the feasibility of a frequency-band-decomposition (FBD) ADC using continuous time bandpass sigma–delta modulators, even in the case of large analog mismatches. The major benefit of such a solution, called extended-frequency-band-decomposition (EFBD) is its low sensitivity to analog parameters. For example, a relative error in the central frequencies of 4% can be accepted without significant degradation in the performance (other published FBD ADCs require a precision of the central frequencies better than 0.1%). This paper will focus on the performance which can be reached with this system, and the architecture of the digital part. The quantization of coefficients and operators will be addressed. It will be shown that a 14 bit resolution can be theoretically reached using 10 sixth-order bandpass modulators at a sampling frequency of 800 MHz which results in a bandwidth of 80 MHz centered around 200 MHz (the resolution depends on the effective quality factor of the filters of the analog modulators)