Neopentyyliglykolin ja propionihapon välisen esteröintireaktion kinetiikka

Glykolien esterit ovat haluttuja pintareaktiivisia aineita. Niitä voidaan valmistaa esteröintireaktiolla karboksyylihappojen kanssa katalyytin läsnä ollessa, jolloin toivottu reaktiotuote on yleensä muodostuva monoesteri. Monoesterin saannon lisäämiseksi reaktiossa muodostuvaa vettä voidaan poistaa jatkuvasti reaktiosta. Reaktion tasapainotilan tutkiminen on kuitenkin tärkeää, jotta reaktion kinetiikka tunnettaisiin mahdollisimman hyvin. Tällöin reaktiotuotteita ei poisteta reaktioseoksesta reaktion aikana. Glykolit esteröityvät happojen kanssa kahdessa vaiheessa. Ensimmäisessä vaiheessa muodostuu monoesteriä ja vettä ja toisessa vaiheessa diesteriä ja vettä. Kokeiden perusteella ensimmäinen vaihe on selvästi toista vaihetta nopeampi reaktio. Kirjallisuudessa on esitetty myös kaksi sivureaktiota, transesteröityminen ja disproportionaatio. Reaktion kinetiikka voidaan kuvata ilman näitä pieniä sivureaktiota, mutta täydellisen kuvaamisen vuoksi on ne myös otettava huomioon. Reaktion kinetiikan tutkimiseksi suoritettiin viisi laboratoriokoetta eri lämpötiloissa neopentyyliglykolilla ja propionihapolla homogeenisen para-tolueenisulfonihapon toimiessa katalyyttina. Lähtöaineiden ja tuotteiden konsentraatioita seurattiin ajan funktiona ja saatujen tulosten perusteella sovitettiin reaktiomekanismin differentiaaliyhtälöiden reaktionopeusvakiot. Nopeusvakioiden lämpötilariippuvuutta tutkittiin Arrheniuksen yhtälön avulla. Lisäksi määritettiin tasapainovakiot kullekin osareaktiolle.

Valssien käytettävyys ja kunnossapito terästehtaassa

Valssi on valssauslaitteiston keskeinen komponentti. Valssauksessa aihiota muokataan kuljettamalla sitä kahden valssin muodostaman raon välistä. Valssit altistuvat valssausprosessissa korkealle lämpötilalle ja pintapaineelle. Valsseille asetettavat vaatimukset tiukkenevat tuottavuuden vaatimusten kiristyessä. Valssit, yhtenä valssauslaitteiston komponenteista, muodostavat suuren osan valssauksen kustannuksista, joten valssien käyttöiän pidentämisen avulla voidaan parantaa valssauksen tuottavuutta ja kustannustehokkuutta. Tässä tutkimuksessa tarkasteltiin valssien käytettävyyttä ja kunnossapitoa, sillä näitä asioita kehittämällä on mahdollista saavuttaa valsseille pidempi kestoikä. Tutkimus toteutettiin kirjallisuusselvityksenä, jota täydennettiin valssausta tekevien yritysten haastatteluilla. Tavoitteena oli kerätä saatavissa oleva kirjallinen ja hiljainen tieto yksiin kansiin ja tutkia mahdollisia syy-seuraussuhteita valssien käytettävyyteen vaikuttavien ilmiöiden sekä valssien kulumisen ja vaurioitumisen välillä. Tutkimuksessa havaittiin, että vauriotyypit ovat riippuvaisia valssausprosessista, jolla tarkoitetaan, että kuuma- ja kylmävalssauksessa esiintyy erilaisia vauriotyyppejä. Kuuma- ja kylmävalssauksessa myös valssien kulumiseen vaikuttavat erilaiset ilmiöt. Valssien kulumista ja vaurioita on mahdollista ehkäistä erilaisilla pintakäsittely- ja pinnoitusmenetelmillä. Valssien kunnossapidon toteutusta tutkittaessa havaittiin, että kuluneiden valssien vaihto kunnostettuihin pyritään suorittamaan mahdollisimman nopeasti ja tätä varten on saatavilla kyseiseen tarkoitukseen kehitettyjä laitteistoja. Kuluneet valssit sorvataan ja hiotaan, jotta niiden pinnasta saadaan tasainen ja saavutetaan haluttu halkaisija. Tämän jälkeen pinnoitusmenetelmiä on mahdollista suorittaa uudelleen. Kunnossapitotoimenpiteet tehdään joko yrityksen omalla korjaamolla tai alihankintana toisen yrityksen tiloissa.

Metal oxides prepared through the nanocasting approach-mechanistic study, surface interactions and applications in separation

Mesoporous metal oxides are nowadays widely used in various technological applications, for instance in catalysis, biomolecular separations and drug delivery. A popular technique used to synthesize mesoporous metal oxides is the nanocasting process. Mesoporous metal oxide replicas are obtained from the impregnation of a porous template with a metal oxide precursor followed by thermal treatment and removal of the template by etching in NaOH or HF solutions. In a similar manner to the traditional casting wherein the product inherits the features of the mold, the metal oxide replicas are supposed to have an inverse structure of the starting porous template. This is however not the case, as broken or deformed particles and other structural defects have all been experienced during nanocasting experiments. Although the nanocasting technique is widely used, not all the processing steps are well understood. Questions over the fidelity of replication and morphology control are yet to be adequately answered. This work therefore attempts to answer some of these questions by elucidating the nanocasting process, pin pointing the crucial steps involved and how to harness this knowledge in making wholesome replicas which are a true replication of the starting templates. The rich surface chemistry of mesoporous metal oxides is an important reason why they are widely used in applications such as catalysis, biomolecular separation, etc. At times the surface is modified or functionalized with organic species for stability or for a particular application. In this work, nanocast metal oxides (TiO2, ZrO2 and SnO2) and SiO2 were modified with amino-containing molecules using four different approaches, namely (a) covalent bonding of 3-aminopropyltriethoxysilane (APTES), (b) adsorption of 2-aminoethyl dihydrogen phosphate (AEDP), (c) surface polymerization of aziridine and (d) adsorption of poly(ethylenimine) (PEI) through electrostatic interactions. Afterwards, the hydrolytic stability of each functionalization was investigated at pH 2 and 10 by zeta potential measurements. The modifications were successful except for the AEDP approach which was unable to produce efficient amino-modification on any of the metal oxides used. The APTES, aziridine and PEI amino-modifications were fairly stable at pH 10 for all the metal oxides tested while only AZ and PEI modified-SnO2 were stable at pH 2 after 40 h. Furthermore, the functionalized metal oxides (SiO2, Mn2O3, ZrO2 and SnO2) were packed into columns for capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Among the functionalized metal oxides, aziridinefunctionalized SiO2, (SiO2-AZ) showed good chemical stability, and was the most useful packing material in both CLC and CEC. Lastly, nanocast metal oxides were synthesized for phosphopeptide enrichment which is a technique used to enrich phosphorylated proteins in biological samples prior to mass spectrometry analysis. By using the nanocasting technique to prepare the metal oxides, the surface area was controlled within a range of 42-75 m2/g thereby enabling an objective comparison of the metal oxides. The binding characteristics of these metal oxides were compared by using samples with different levels of complexity such as synthetic peptides and cell lysates. The results show that nanocast TiO2, ZrO2, Fe2O3 and In2O3 have comparable binding characteristics. Furthermore, In2O3 which is a novel material in phosphopeptide enrichment applications performed comparably with standard TiO2 which is the benchmark for such phosphopeptide enrichment procedures. The performance of the metal oxides was explained by ranking the metal oxides according to their isoelectric points and acidity. Overall, the clarification of the nanocasting process provided in this work will aid the synthesis of metal oxides with true fidelity of replication. Also, the different applications of the metal oxides based on their surface interactions and binding characteristics show the versatility of metal oxide materials. Some of these results can form the basis from which further applications and protocols can be developed.

Ohutlevykotelon valmistettavuuden ja pinnoitettavuuden huomioiminen suunnittelussa

Korkean IP-luokituksen ohutlevykotelointi on haastava kokonaisuus. Koteloinnin tiivistys ruiskutettavalla polyureapinnoitteella edellyttää usean osa-alueen samanaikaista hallintaa. Kotelo on alusta alkaen suunniteltava pinnoitettavaksi, sillä pinnoitus asettaa lukuisia vaatimuksia ja rajoituksia esimerkiksi käytettäville muodoille, rakenteille ja liittämismenetelmille. Polyurea on elastomeeri, josta valmistettua pinnoitetta voidaan levittää erityisellä ruiskutuslaitteistolla. Polyureapinnoite sallii kotelon asentamisen vaikeisiin olosuhteisiin, sillä se kestää kemikaaleja, kulutusta ja iskuja sekä tarjoaa tiiveyden lisäksi korroosiosuojan koteloinnille. Pinnoitteen ominaisuuksia, kuten kovuutta, elastisuutta ja kemikaalien sekä UV-säteilyn kestoa voidaan räätälöidä käyttökohteen mukaan. Polyurepinnoitteeella pinnoitettavat pinnat on pyrittävä pitämään mahdollisimman yksinkertaisina, mikä tarkoittaa käytännössä kaikenlaisten kohoumien, ulkonevien osien, reikien ja muiden epäjatkuvuuskohtien välttämistä. Kaikki epäjatkuvuuskohdat vaativat erityishuomiota pinnoituksen aikana, sillä epäjatkuvuuskohtien onnistunut pinnoitus vaatii ruiskutusta useasta suunnasta, mikä lisää virhemahdollisuuksia ja siten vaarantaa koteloinnin tiiveyden. Liittämismenetelmät ovat yksinkertaisten muotojen ohella avainasemassa pinnoituksen onnistumisen kannalta. Menetelmistä tulee suosia sellaisia, joiden pinnoitettavaan pintaan aiheuttama epäjatkuvuuskohta on mahdollisimman vähäinen. Tällaisia menetelmiä ovat esimerkiksi vastuspistehitsaus ja puristeruuvi.

Tintype of Unidentified African American Woman Leaning on Chair [n.d.]

A small tintype of a young Black woman dressed in white. The date, location and name of the photographer are unknown. This tintype was among the family memorabilia belonging to Iris Sloman Bell, of St. Catharines, Ontario. Relatives of the Sloman - Bell family are descended from former American slaves."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of Two Young Women, Seated, with Man [n.d.]

A small tintype of three unidentified individuals, two women, seated, and a young Black gentleman, standing. The date, location and name of the photographer are unknown. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families have relatives who were former American slaves who came to Canada. They later settled in the London and St. Catharines areas of Ontario."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of African American Gentleman Seated on Stool [n.d.]

An unidentified man poses for his portrait seated on a stool in this undated black and white tintype photograph. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. Relatives of the Bell - Sloman family include former Black slaves from the United States who settled in Canada."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of Man Smoking a Cigar [n.d.]

This small black and white tintype photograph shows a young Black gentleman smoking a cigar. No date or location is provided. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. Relatives of the Sloman - Bell families are descended from former slaves from the United States who settled in Canada."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of Young African American Woman Seated at Table [n.d.]

Black and white tintype of an unidentified woman seated with hand-colored red detail on her scarf and the tablecloth. The date, location and photographer are unknown. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. Relatives of the Bell - Sloman families include former slaves from the United States who escaped to Canada. They later settled in the London and St. Catharines areas of southern Ontario."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype Portrait of African American Couple [n.d.]

An unidentified couple is pictured in this early black and white tintype photograph. The date, location and name of the photographer are unknown. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Bell - Sloman families have relatives who are descended from African American slaves who settled in Canada."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of Sad Young Black Girl Perched on Bench [n.d.]

This unhappy looking young girl is featured in an early black and white tintype photograph. The date, location and name of the photographer are unknown. This small tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families have descendants who are former slaves from the United States."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Small Tintype of Young Black Woman, Seated [n.d.]

A young woman seated with arm resting on a side table is pictured in this small black and white tintype photograph. The date, location and name of the photographer are unknown. This tintype was among the family memorabilia in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families have relatives who were former slaves from the United States. They escaped to Canada and later settled in the London and St. Catharines areas of Ontario."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of Girl Peering through Lattice [n.d.]

A young African American girl peers through a lattice window in an unknown photographer's studio in this small black and white tintype. The girl in the photo is unidentified. There are slight scratches on the surface of the tintype, which is cut in a hexagonal shape. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families have relatives who are descended from Black slaves from the United States."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of African American Man Standing at Wooden Fence [n.d.]

An unidentified African American man poses beside a wooden fence in the studio of an unknown photographer in this small black and white tintype photograph. A painted landscape serves as the backdrop. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families are descended from former American slaves who settled in Canada."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html

Tintype of African American Woman Standing with Book [n.d.]

A woman standing with a book beside a table covered with a decorative cloth is featured in this small black and white tintype photograph. The tintype has been mounted in a paper slip frame with gold edging. There is a small area of red, hand-colored highlighting on the tablecloth. The backdrop appears to be a painted landscape scene. The tintype is undated and there is no indication of the identity of the woman in the photo or the photographer. This tintype was in the possession of Iris Sloman Bell, of St. Catharines, Ontario. The Sloman - Bell families have relatives who are former slaves from the United States who later settled in southern Ontario."Tintypes were the invention of Prof. Hamilton Smith of Ohio. They begin as thin sheets of iron, covered with a layer of black paint. This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. First made in 1856, millions were produced well into the twentieth century. When tintypes were finished in the same sorts of mats and cases used for ambrotypes, it can be almost impossible to distinguish which process was used without removing the image to examine the substrate." Source: American Museum of Photography http://www.photographymuseum.com/primer.html