40 research outputs found
Testing of modern catalysts for the synthesis of methanol
Zaradi sodobnega načina življenja se zelo hitro povečuje koncentracija ogljikovega dioksida v ozračju. Strokovnjaki iščejo rešitve za zmanjšanje njegove koncentracije. Ena izmed rešitev je njegova pretvorba v metanol. Pri tem se v industriji uporabljajo katalizatorji, ki pospešijo določene kemijske reakcije za pretvorbo reaktanta v željeni produkt. Pri razvoju katalizatorjev se izvajajo različna testiranja, da najdemo najbolj aktivnega, specifičnega in stabilnega za določeno reakcijo.
Nekateri izmed katalizatorjev, kateri se uporabljajo pri sintezi metanola so Cu/ZnO/Al2O3, Cu/SrTiO3 in Pd/In2O3, ki so jih testirali na Kemijskem inštitutu v Ljubljani. Podatke testiranj sem analizirala in iz njih pridobila, kako na selektivnost, aktivnost in aktivacijsko energijo vpliva različen nanos nanodelcev bakra na katalizatorju SrTiO3. Te katalizatorje sem primerjala tudi s Pd/In2O3 in Cu/ZnO/Al2O3.
Ugotovitve so pokazale, da se aktivnosti katalizatorjev z različnim nanosom bakra na SrTiO3 v odvisnosti od časa v večini primerov ne spreminjajo, selektivnosti pa naraščajo.
Navidezni aktivacijski energiji tvorbe metanola pri katalizatorjema z 0,5 in 5 % nanosom bakra na SrTiO3 sta med seboj precej podobni, skoraj enaki. Pri primerjanju različnih tipov katalizatorjev rezultati kažejo, da ima najvišjo navidezno aktivacijsko energijo nastanka metanola Pd/In2O3, najnižjo pa Cu/ZnO/Al2O3.Due to the modern way of life, the concentration of carbon dioxide in the atmosphere is increasing very quickly. Experts are looking for solutions to reduce its concentration. One of the solutions is its conversion to methanol. In doing so, catalysts are used in industry to accelerate certain chemical reactions to convert the reactant to the desired product. In the development of catalysts, various tests are performed to find the most active, specific and stable one for a particular reaction.
Some of the catalysts used in the synthesis of methanol are Cu/ZnO/Al2O3, Cu/SrTiO3 and Pd/In2O3 and they were tested at the Institute of Chemistry in Ljubljana. I analyzed the test data and found out how the selectivity, activity and activation energy are affected by different deposition of copper nanoparticles on the SrTiO3 catalyst. I also compared these catalysts with Pd/In2O3 and Cu/ZnO/Al2O3.
The findings showed that the activities of catalysts with different copper deposition on SrTiO3 do not change in most cases depending on time, and the selectivities increase.
The apparent activation energies of methanol formation in catalysts with 0.5 and 5 % copper deposition on SrTiO3 are quite similar, almost identical. When comparing different types of catalysts, the results show that Pd/In2O3 has the highest apparent activation energy of methanol formation and Cu/ZnO/Al2O3 the lowest one
Postpartum Depression and its Impact on Women\u27s Lives
V diplomskem delu raziskujem temo poporodne depresije in kako je ta povezana ter kako vpliva na življenja žensk. V teoretičnem delu se posvetim razlagi tega, kaj ženske doživljajo med nosečnostjo in po porodu. Razložim splošne značilnosti nosečnosti, opišem nosečnost po obdobjih (vsako trimesečje) in kaj lahko ženska v vsakem od teh obdobij prestaja. Pri temi poroda prav tako opišem potek poroda, njegove faze, da si posameznik lažje predstavlja izkušnjo ženske, hkrati pa poudarjam, da so opisi splošni in se razlikujejo od ženske do ženske. Tematiko, ki je v zvezi z materinstvom, razdelim na dve podtemi, ki govorita o družbenem konstruktu materinstva in o materah v medijih in na družbenih omrežjih. Za konec pa pojasnim razlike med različnimi poporodnimi stiskami in podrobneje opišem poporodno depresijo (kako se kaže, s kakšnimi simptomi, kako jo zdravimo ...). V raziskovalnem delu me je zanimalo, kako ženske doživljajo obdobje nosečnosti in materinstva (prehod v materinstvo)s kakšnimi težavami se srečujejo ob teh prelomnih trenutkihkako bližnji sprejemajo nosečnosti in materinstvo ženske ter kakšno oporo jim dajejo. Ugotavljala sem tudi, ali se težave v obdobju nosečnosti povezujejo s pojavnostjo poporodne depresije. Raziskava je pokazala, da so ženske z izkušnjo poporodne depresije imele težave v nosečnosti, vendar tega ne moremo zagotovo povezati, saj so obdobje nosečnosti sicer označile kot lepo in lahko. Pokazalo se je tudi, da jim je prehod v materinstvo predstavljal težavo, saj so se bale neznanega in novega. Pomembna je tudi ugotovitev, da ženske pripisujejo velik pomen družbenemu konstruktu idealne mame in da jih ta močno obremenjuje. Intervjuvane ženske so imele v času po porodu dovolj opore bližnjih, vendar jim kljub vsemu največjo stisko povzroča osamljenost, ki je posledica izolacije od preostale družbe.In my graduation thesis I examine the topic of postpartum depression and how it relates to the lives of women and how it affects their lives. In the theoretical part, I focus on explaining what women experience during pregnancy and after childbirth. I explain the general characteristics of pregnancyI describe pregnancy by stages (each trimester) and what a woman can experience during each of these stages. In the subject of childbirth, I also describe the course of childbirth and its phases for an individual to better understand what a woman experiences, while emphasizing that the descriptions are general and depend on every woman individually. I divide the topic concerning motherhood into two sub-topics that discuss the social construct of motherhood and mothers in the media and on social networks. Finally, I explain the differences between different types of postpartum distress and describe postpartum depression in more detail (how it manifests itself, what the symptoms are, how to treat it, etc). In the empirical part, I was interested in how women experience the time of pregnancy and maternity (transition to motherhood)what difficulties they encounter at these turning pointshow their loved ones accept a woman\u27s pregnancy and motherhood and what support they offer her. I also studied whether problems during pregnancy resulted in postpartum depression. The study showed that women with postpartum depression experienced pregnancy problems, but we cannot substantiate this for certainly as they characterized their pregnancy term as a beautiful and easy time. The study also showed that the transition to motherhood represented a problem for them as they feared the new and the unknown. It is also important to note that women attach great importance to the social construct of the ideal mother and that she is greatly burdened by it. The women interviewed told they had sufficient support from their loved ones after childbirth, but despite everything their greatest distress was loneliness resulting from isolation from the rest of society
MINLP Synthesis of Processes for the Production of Biogas from Organic and Animal Waste
This paper describes a superstructure approach for the synthesis of biogas processes simultaneously with the selection of different process background alternatives. The superstructure consists of anaerobic fermentation under thermophilic or mesophilic conditions,
including options for a rendering plant, with different organic and animal wastes from either existing or new plants, different water supplies, wastewater treatments and biogas usage options. An aggregated mathematical model with an economic objective function, formulated as a mixed-integer nonlinear programming (MINLP) problem, was developed. An industrial case study was applied to an existing large-scale meat company, in order to describe the mathematical model and illustrate the MINLP synthesis approach.
The optimal solution indicates that significant benefit can be obtained if biogas processes are selected simultaneously with the selection of different process background alternatives thus yielding the optimal integration of biogas processes with their background
Recent advances in resource conservation and planning-a review
This paper provides a dedicated overview of the Special Issue of Asia Pacific Journal of Chemical Engineering. It highlights the current issues and challenges surrounding ‘Resource Conservation and Planning’ and provides an update to practitioners, researchers, academicians and policy makers on some recent technological developments in this area. This overview includes a compilation of ten papers that focus on ways to: (1) select the best resource conservation and planning software tools; (2) design sustainable products and process systems that utilise less resources; (3) minimise the demand for fresh resources by converting wastes to resources; (4) assess the environmental impacts of products and processes; (5) identify, monitor and manage river pollutions
Optimiranje postopka protimikrobnega apretiranja bombažnih tkanin za senčila : diplomsko delo
A COMPARISON OF WEB APPLICATION PERFORMANCE TESTING TOOLS
Hitra rast uporabe spleta in spletnih storitev je povzročila potrebo po vrednotenju in zagotavljanju ustreznih zmogljivosti spletnih aplikacij tako glede odzivnih časov, števila istočasnih uporabnikov, prepustnosti kot porabe virov. V diplomski nalogi smo opisali namen, vrste in cilje testiranja zmogljivosti. Nato smo se osredotočili na nekatera izmed najpogosteje uporabljenih brezplačnih in komercialnih orodij za testiranje zmogljivosti ter jih med seboj primerjali. Proces testiranja zmogljivosti v praksi smo prikazali z uporabo odprtokodnega orodja Apache JMeter in komercialne rešitve HP LoadRunner.The rapid growth of internet use and online services has led to the need for evaluation and provision of appropriate performance of web applications in terms of response times, number of concurrent users, throughput and usage of resources. In this paper we described a purpose, types and goals of performance testing. Further we focused on some of the most widely used free and commercial tools and compared them to each other. The process of performance testing in practice we demonstrated with the use of an open source tool Apache JMeter and a commercial solution HP LoadRunner
THE INFLUENCE OF PATIENT AGGRESSION ON STAFF IN PSYCHIATRIC NURSING CARE
Teoretična izhodišča in namen: Diplomsko delo je sestavljeno iz teoretičnega in empiričnega dela in predstavlja agresijo, pojavnost in vpliv le te na zaposlene v psihiatrični zdravstveni negi. Delo zaposlenih na psihiatričnem področju zahteva, da se z agresijo spoprijemamo brez pomoči varnostnih služb, zato je zelo pomembno, da poznamo vse dejavnike tveganja za nastanek in porast agresije pri pacientu z duševno motnjo, zato smo v diplomskem delu dali velik poudarek pri poznavanju dejavnikov tveganja in evalvaciji agresivnega vedenja. Zanimalo nas je tudi v kolikšni meri se pojavlja agresija s strani pacientov na zaposlene v psihiatrični zdravstveni negi in kako nanje vpliva.
Raziskovalne metode: Pri raziskovanju smo uporabili kvantitativno metodo dela. V raziskovanje smo vključili 50 članov negovalnega tima iz področja psihiatrične zdravstvene nege iz dveh različnih psihiatričnih ustanov.
Rezultati: Rezultati raziskave so pokazali, da anketiranci opažajo večjo pojavnost agresije s strani pacientov v vseh oblikah na zaprtih oddelkih kot na odprtih oddelkih ustanov, kar lahko dokažemo s potrjeno hipotezo. Rezultati raziskave so pokazali tudi, da agresija s strani pacientov ima vpliv na zaposlene v psihiatrični zdravstveni negi.
Sklep: Zdravstvenim delavcem agresija s strani pacientov predstavlja veliko grožnjo, prav zaradi velike pojavnosti le te, kar je razvidno iz več raziskav. Zaradi tega je izjemno pomembno poznavanje dejavnikov tveganja za agresivno vedenje in pravilno ukrepanje ob le tem.Theoretical baseline and purpose: The thesis consists of theoretical and empirical work and introduces aggression, incidence and its impact on employees in psychiatric nursing. The work of employees in the psychiatric field demands facing aggression without the help of security services. Therefore it is very important to be familiar with risk factors for the emergence and increase of aggression with a patient with a mental disorder. Thus our thesis emphasises knowledge of risk factors and evaluation of aggressive behavior. We are also interested in the extent of aggression from patients towards staff in psychiatric nursing and how it affects them.
Research methods: Quantitative manner of work was being used for research. 50 members of the nursing team in the field of psychiatric nursing were involved. They were from two different psychiatric institutions.
Results: The results have shown that respondents experienced a higher incidence of aggression by patients in both closed wards as in open sections of psychiatric institutions, which can be proved with a confirmed hypothesis. The survey results also showed that aggression by patients has an impact on employees in psychiatric nursing.
Conclusion: For medical staff, patient\u27s aggresion presents a major threat, mainly because of the large incidence. Several studies shows that the incidence is high. For this reason, it is extremely important to be familiar with risk factors for aggressive behavior and proper response to aggressive behavior from patients
Optimization of processes for biogas production from animal and other organic wastes using the computer aided process engineering
Eden glavnih okoljevarstvenih problemov živilskopredelovalne industrije je nenehno naraščajoča proizvodnja odpadkov različnega izvora. Proizvodnja bioplina iz organskih in živalskih odpadkov z anaerobno fermentacijo je primeren način za predelavo teh odpadkov. Predelava prinaša mnoge okoljske, ekonomske in družbene koristi.
Po drugi strani procesna sistemska tehnika s svojimi vrhunskimi orodji, ki temeljijo na matematičnem programiranju oz. optimizaciji, omogoča generiranje optimalnih in dopustnih rešitev za doseganje višjega nivoja konkurenčnosti proizvodnih podjetij.
V doktorski disertaciji obravnavamo uporabo algoritemskih metod procesne integracije v industrijskem merilu in sicer na primeru velikega živilskopredelovalnega podjetja za doseganje okoljsko sprejemljivih rešitev pri ravnanju in predelavi živalskih substratov in organskih odpadkov. Na osnovi iniciative živilskopredelovalne industrije smo za sintezo procesov proizvodnje bioplina razvili matematični model, ki omogoča selekcijo optimalnega procesa proizvodnje bioplina in sestave vhodnega substrata ter simultano optimizacijo snovnih tokov, investicijskih sredstev in obratovalnih stroškov procesa. Z matematičnim programiranjem smo postopoma najprej izvedli sintezo procesa za proizvodnjo bioplina, nato simultano sintezo s toplotno integracijo in nazadnje še sintezo procesa s simultano sintezo omrežja toplotnih prenosnikov.
Tako smo najprej razvili mešano celoštevilski nelinearni (MINLP) model za sintezo procesov proizvodnje bioplina. V primeru simultane toplotne integracije in sinteze procesa smo ga nadgradili z modelom za simultano toplotno integracijo (Duran in Grossmann, 1986), ki smo ga za potrebe industrijskega problema prilagodili za konstantne temperature in izotermno mešanje procesnih tokov. Model omogoča določitev optimalne procesne sheme in minimalne porabe pogonskih sredstev za množico alternativnih toplih in hladnih tokov procesa proizvodnje bioplina. Z omenjeno modifikacijo simultanega modela toplotne integracije in s konveksifikacijo konkavnih investicijskih členov v namenski funkciji z odsekovno linearizacijo smo razvili mešano celoštevilski linearni model (MILP), ki omogoča reševanje industrijskega problema do globalnih rešitev.
Ker pri reševanju sinteznih problemov praviloma dobimo boljše rešitve, če obravnavamo snovne in energetske bilance ter investicijska sredstva in obratovalne stroške hkrati, smo se v končni fazi sinteze procesa odločili, da tudi omrežje toplotnih prenosnikov (OTP) pri proizvodnji bioplina sintetiziramo simultano s procesom. Tako smo celotni sintezni problem zapisali na osnovi dveh med seboj povezanih superstruktur v obliki mešano celoštevilskega nelinearnega problema. Pri tem smo predlagali novo superstrukturo procesnih tokov, kjer se lahko procesni tokovi ne-izotermno mešajo in kombinirajo. Predhodno razviti model MINLP za sintezo procesa proizvodnje bioplina smo nadgradili z večstopenjskim modelom za simultano sintezo omrežja toplotnih prenosnikov (Yee in Grossmann, 1990), ki smo ga modificirali za potrebe simultanega pristopa in nove superstrukture procesnih tokov. Tako dodelan model omogoča simultano določitev optimalne procesne sheme z optimalnim omrežjem toplotnih prenosnikov pri optimalni sestavi in porabi vhodnih surovin, optimalnih obratovalnih stroških in investicijskih sredstvih.The main environmental problem relating to the meat processing industry is the constantly increasing production of wastes from various sources. Anaerobic digestion can be regarded as an efficient, economical, and sustainable solution for converting organic and animal wastes into precious biogas and other products. On the other hand, process systems engineering with its efficient computer-aided, mathematical programming-based tools, enables us to generate optimal and useful solutions and thus facilitate the achievement of higher competitiveness from process industries.
In this respect, the topic of this PhD thesis is devoted to the field of process integration: different algorithmic methods were applied in order to obtain economically- efficient and yet, environmentally benign solutions for the utilization of different animal and organic wastes within an existing large-scale meat company. A mathematical model for the synthesis of biogas process was developed based on the initiative of this meat company. This model enables the selection of an optimal biogas process flow sheet, optimal consumption of substrates and optimal production of biogas and other products, by the simultaneous optimization of mass flow rates, operating costs, and investment of the process. The mathematical programming approach was applied for increasing complexities, firstly to the synthesis of biogas process alone, then to the simultaneous heat integration and synthesis of the biogas process and, finally, to the simultaneous synthesis of the biogas process and its integrated heat exchanger network.
Firstly, a mixed integer nonlinear programming (MINLP) model for the synthesis of biogas processes was developed. This model was then upgraded with heat balances and extended by a simultaneous heat integration model developed by Duran and Grossmann (1986) in order to perform the simultaneous heat integration and synthesis of the biogas process. The original heat integration model was modified in order to correspond to the specific needs of industrial applications. It was assumed that all units were operating at fixed temperatures and the process streams mixed isothermally. By applying the mentioned modifications and replacing concave investment terms within the objective function with convex ones by the use of a piecewise linearization method, we developed a mixed integer linear (MILP) model, which was capable of obtaining global optimal solutions for the given industrial problem. This model determines globally optimal process schemes for a set of alternative hot and cold process streams at minimum consumption of utilities.
As superior solutions to the synthesis problems were expected when the mass and energy balances, as well as the capital and operating costs were optimized simultaneously, during the final stage of our biogas process synthesis we performed the process synthesis simultaneously with the synthesis of its heat integrated heat exchanger network (HEN). The combined synthesis problem was formulated as an MINLP problem based on the mathematical description of combined process/HEN superstructure. In addition, a new process streams superstructure was proposed where the streams could be non-isothermally mixed and merged into a significantly smaller set of streams in order to obtain optimal and yet simpler solutions. The final synthesis model thus consists of the MINLP model for biogas process synthesis, the MINLP model for the simultaneous synthesis of heat integrated HEN (Yee in Grossmann, 1990), now modified to enable the simultaneous process and its HEN synthesis, and the mass and energy balances models for the process streams superstructure. The developed MINLP model enables the selection of an optimal biogas process scheme together with its HEN at the optimal composition and consumption of inlet substrates, optimal operating costs, and investment