Novi algoritam za kompresiju seizmičkih podataka velike amplitudske rezolucije

Renewable sources cannot meet energy demand of a growing global market. Therefore, it is expected that oil & gas will remain a substantial sources of energy in a coming years. To find a new oil & gas deposits that would satisfy growing global energy demands, significant efforts are constantly involved in finding ways to increase efficiency of a seismic surveys. It is commonly considered that, in an initial phase of exploration and production of a new fields, high-resolution and high-quality images of the subsurface are of the great importance. As one part in the seismic data processing chain, efficient managing and delivering of a large data sets, that are vastly produced by the industry during seismic surveys, becomes extremely important in order to facilitate further seismic data processing and interpretation. In this respect, efficiency to a large extent relies on the efficiency of the compression scheme, which is often required to enable faster transfer and access to data, as well as efficient data storage. Motivated by the superior performance of High Efficiency Video Coding (HEVC), and driven by the rapid growth in data volume produced by seismic surveys, this work explores a 32 bits per pixel (b/p) extension of the HEVC codec for compression of seismic data. It is proposed to reassemble seismic slices in a format that corresponds to video signal and benefit from the coding gain achieved by HEVC inter mode, besides the possible advantages of the (still image) HEVC intra mode. To this end, this work modifies almost all components of the original HEVC codec to cater for high bit-depth coding of seismic data: Lagrange multiplier used in optimization of the coding parameters has been adapted to the new data statistics, core transform and quantization have been reimplemented to handle the increased bit-depth range, and modified adaptive binary arithmetic coder has been employed for efficient entropy coding. In addition, optimized block selection, reduced intra prediction modes, and flexible motion estimation are tested to adapt to the structure of seismic data. Even though the new codec after implementation of the proposed modifications goes beyond the standardized HEVC, it still maintains a generic HEVC structure, and it is developed under the general HEVC framework. There is no similar work in the field of the seismic data compression that uses the HEVC as a base codec setting. Thus, a specific codec design has been tailored which, when compared to the JPEG-XR and commercial wavelet-based codec, significantly improves the peak-signal-tonoise- ratio (PSNR) vs. compression ratio performance for 32 b/p seismic data. Depending on a proposed configurations, PSNR gain goes from 3.39 dB up to 9.48 dB. Also, relying on the specific characteristics of seismic data, an optimized encoder is proposed in this work. It reduces encoding time by 67.17% for All-I configuration on trace image dataset, and 67.39% for All-I, 97.96% for P2-configuration and 98.64% for B-configuration on 3D wavefield dataset, with negligible coding performance losses. As a side contribution of this work, HEVC is analyzed within all of its functional units, so that the presented work itself can serve as a specific overview of methods incorporated into the standard

Novi algoritam za kompresiju seizmičkih podataka velike amplitudske rezolucije

Renewable sources cannot meet energy demand of a growing global market. Therefore, it is expected that oil & gas will remain a substantial sources of energy in a coming years. To find a new oil & gas deposits that would satisfy growing global energy demands, significant efforts are constantly involved in finding ways to increase efficiency of a seismic surveys. It is commonly considered that, in an initial phase of exploration and production of a new fields, high-resolution and high-quality images of the subsurface are of the great importance. As one part in the seismic data processing chain, efficient managing and delivering of a large data sets, that are vastly produced by the industry during seismic surveys, becomes extremely important in order to facilitate further seismic data processing and interpretation. In this respect, efficiency to a large extent relies on the efficiency of the compression scheme, which is often required to enable faster transfer and access to data, as well as efficient data storage. Motivated by the superior performance of High Efficiency Video Coding (HEVC), and driven by the rapid growth in data volume produced by seismic surveys, this work explores a 32 bits per pixel (b/p) extension of the HEVC codec for compression of seismic data. It is proposed to reassemble seismic slices in a format that corresponds to video signal and benefit from the coding gain achieved by HEVC inter mode, besides the possible advantages of the (still image) HEVC intra mode. To this end, this work modifies almost all components of the original HEVC codec to cater for high bit-depth coding of seismic data: Lagrange multiplier used in optimization of the coding parameters has been adapted to the new data statistics, core transform and quantization have been reimplemented to handle the increased bit-depth range, and modified adaptive binary arithmetic coder has been employed for efficient entropy coding. In addition, optimized block selection, reduced intra prediction modes, and flexible motion estimation are tested to adapt to the structure of seismic data. Even though the new codec after implementation of the proposed modifications goes beyond the standardized HEVC, it still maintains a generic HEVC structure, and it is developed under the general HEVC framework. There is no similar work in the field of the seismic data compression that uses the HEVC as a base codec setting. Thus, a specific codec design has been tailored which, when compared to the JPEG-XR and commercial wavelet-based codec, significantly improves the peak-signal-tonoise- ratio (PSNR) vs. compression ratio performance for 32 b/p seismic data. Depending on a proposed configurations, PSNR gain goes from 3.39 dB up to 9.48 dB. Also, relying on the specific characteristics of seismic data, an optimized encoder is proposed in this work. It reduces encoding time by 67.17% for All-I configuration on trace image dataset, and 67.39% for All-I, 97.96% for P2-configuration and 98.64% for B-configuration on 3D wavefield dataset, with negligible coding performance losses. As a side contribution of this work, HEVC is analyzed within all of its functional units, so that the presented work itself can serve as a specific overview of methods incorporated into the standard

Brewer’s spent grain – raw material in lactic acid fermentation

Pivski trop čini približno 85% od ukupnih sporednih proizvoda proizvodnje piva, i dostupan je po veoma niskim cenama tokom čitave godine. Pivski trop ima veliku perspektivu za primenu u biotehnologiji i proizvodnji visoko vrednih proizvoda. Jedna od veoma ekološki i ekonomski isplativih alternativa je upotreba pivskog tropa u proizvodnji mlečne kiseline, jer se poslednjih par decenija uočava intenzivan rast potražnje za mlečnom kiselinom. Mlečna kiselina je najvažnija hidroksikarbonska kiselina široko rasprostranjena u prirodi, sa velikom primenom u prehrambenoj, farmaceutskoj, tekstilnoj i hemijskoj industriji i industriji prerade kože. Cilj istraživanja ove doktorske disertacije je ispitivanje primene pivskog tropa u proizvodnji mlečne kiseline. Prvo je izvršena optimizacija enzimske hidrolize pivskog tropa u cilju dobijanja što je moguće veće koncentacije redukujućih šećera neophodne za mlečno-kiselu fermentaciju. Hidrolizat pivskog tropa je dobijen enzimskom hidrolizom dodatkom komercijalnih enzima za razgradnju skroba i celuloze. Parametri čiji je uticaj na efikasnost enzimske hidrolize ispitanu su: pH vrednost, temperatura hidrolize i količina dodatih enzima. Nakon što su određeni najbolji uslovi razgranje pivskog tropa, dobijeni postupak hidrolize je primenjen u proizvodnji hidrolizata pivskog tropa koji je korišćen u mlečno-kiselim fermentacijama. Nakon toga je ispitana mlečno-kisela fermentacija sa dva proizvodna mikoorganizma. Kao proizvodni mikroorganizmi u mlečno-kiselim fermentacijama primenjena su dva soja bakterija mlečne kiseline: Lactobacillus fermentum PL-1 i Lactobacillus rhamnosus ATCC 7469. Ispitan je uticaj dodatka različitih koncentracija ekstrakta kvasca (0,5-5,0%) uz korekciju pH vrednosti tokom fermentacije sa dodatkom kalcijum-karbonata. U zavisnosti od udela L-(+)- i D-(-)-mlečne kiseline koje nastaju tokom fermentacije izabran je proizvodni mikroorganizam koji proizvodi više L-(+)-mlečne kiseline. U daljim ispitivanjima je ispitan uticaj korekcije pH pomoću natrijum-hidroksida kao i dodatak različitih koncentracija ekstrakta kvasca (0,5-5,0%) i redukujućih šećera (2,7; 5,4 i 8,1%) u hidrolizatu pivskog tropa na mlečno-kiselu fermentaciju pomoću odabranog soja bakterija mlečne kiseline. Na osnovu dobijenih rezultata izabrana je najbolja koncentracija redukujućih šećera i ekstrakta kvasca koji će se koristiti u daljim istraživanjima. Takođe je ispitana i mogućnost zamene skupog ekstrakta kvasca i glukoze sa obnovljivim sirovinama, kao što su pivski kvasac, džibra i bistra džibra. Ispitan je uticaj dodatka različitih koncentracija pivskog kvasca (0,5-5,0%), džibre (5-20%) i bistre džibre (5-50%) pre fermentacije kao i dodatak bistre džibre u dolivnoj fermentaciji, na mlečno-kiselu fermentaciju hidrolizata pivskog tropa. Ispitan je i dolivni postupak fermentacije hidrolizata pivskog tropa dodatkom glukoze, glukoze i ekstrakta kvasca i sladovine. Takođe je ispitana mogućnost izvođenja više uzastopnih fermentacija sa imobilisanim ćelijama odabranog soja bakterija mlečne kiseline u kalcijum-alginatu. Na osnovu eksperimentalnih rezultata zaključujeno je da je dodatak kalcijum-karbonata imao pozitivan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. Sa dodatkom kalcijum-karbonata povećali su se utrošak redukujućih šećera, koncentracija i prinos mlečne kiseline i vijabilnost ćelija L. fermentum i L. rhamnosus. Ekstrakt kvasca i kalcijum-karbonat su imali značajan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. U fermentacijama sa L. fermentum najveći prinos ukupne mlečne kiseline (44%) je postignut sa dodatkom 5,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. U fermentacijama sa L. rhamnosus najveći prinos ukupne mlečne kiseline (98%) i L-(+)-mlečne kiseline (96%) je ostvaren u fermentaciji sa dodatkom 2,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. Na osnovu rezultata odlučeno je da se u daljim ispitivanjima mlečno-kisele fermentacije hidrolizata pivskog tropa kao proizvodni mikoorganizam koristi L. rhamnosus. Primenom natrijum-hidroksida za korekciju pH je skratila fermentaciju za 48 sati a ostvareno je i značajno povećanje zapreminske produktivnosti L-(+)-mlečne kiseline (za 200%, povećanje sa 0,21 na 0,63 g/l·h-1). Korekcija pH u svim daljim istraživanjima je vršena sa dodatkom natrijum-hidroksida. U mlečno-kiselim fermentacijama sa različitim početnim koncentracijama redukujućih šećera (2,7; 5,4 i 8,1%) i sa dodatkom različitih koncentracija ekstrakta kvasca (0,5-5,0%), najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 91,29% i 1,69 g/l·h-1, kao i vijabilnost ćelija L. rhamnosus od 9,7·109 CFU/ml ostvareni su u fermentaciji sa početniom koncentracijom redukujućih šećera od 5,4% i dodatkom 5,0% ekstrakta kvasca. Na osnovu ostvarenih rezultata u istraživanjima sa dodatkom džibre i dodacima tokom fermentacije kao i u fermentacijama sa imobilisanim ćelijama je korišćen hidrolizat pivskog tropa sa početnom koncentracijom redukujućih šećera od 5,4%. U mlečno kiseloj fermentaciji sa dodatkom pivskog kvasca najveći prinos L-(+)-mlečne kiseline (89,01%) i zapreminska produktivnost (0,89 g/l·h-1) L-(+)-mlečne kiseline su ostvareni u fermentaciji sa dodatkom 5,0% pivskog kvasca i korekcijom početne koncentracije redukujućih šećera na 5,0%. Na osnovu rezultata utvrđeno je da se može izvršiti delimična ili potpuna zamena ekstrakta kvasca pivskim kvascem uz značajno smanjenje cene podloge za mlečno-kiselu fermentaciju, bez značajnog smanjenja efikasnosti mlečno-kisele fermentacije. U mlečno-kiseloj fermentaciji sa dodatkom džibre i bistre džibre najveć koncetracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline od 31,03 g/l, 86,15% i 0,93 g/l·h-1, ostvareni su u fermentaciji sa dodatkom 50% bistre džibre. Najviša koncentracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline ostvareni u dolivnoj fermentaciji sa dodatkom glukoze i bistre džibre tokom mlečno-kisele fermentacije su iznosili su 48,02 g/l, 87,82% i 0,96 g/l·h-1. U fermentacijama sa dodatkom nutritijenata tokom mlečno-kisele fermentacije najveća vrednost koncetracije, prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline od 116,08 g/l, 93,32% i 2,04 g/L·h-1, su ostvarene u fermentaciji sa dodatkom glukoze i ekstrakta kvasca tokom fermentacije. Na osnovu rezultata utvrđeno je da se dolivni postupak fermentacije može koristiti u cilju povećanja efikasnosti mlečno-kisele fermentacije. Izvršena je imobilizacija ćelija L. rhamnosus u kalcijum-alginatu uz izuzetno visoku vijabilnost (1010 CFU/ml). Imobilisane ćelije L. rhamnosus su uspešno korišćene u tri mlečno-kisele fermentacije. Prinos L-(+)-mlečne kiseline i zapreminska produktivnost su u sve tri fermentacije bili izuzetno visoki, pri čemu su najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 95,2% i 1,76 g/l·h-1, ostvareni u drugoj fermentaciji. Upotrebom imobilisanih ćelija L. rhamnosus je osim povećanja prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline skraćena fermentacija za 12 sati u poređenju sa šaržnim fermentacijama.Brewers spent grain represents (BSG) about 85% of the total by-products from brewing process and is available at low price during the whole year. Due to its chemical composition BSG has great potential use in biotechnology and production of high-value products. One of very eco-friendly and economical alternative uses of BSG is in production of lactic acid (LA), since in the last few decades the demand for the LA has significantly risen, mostly because of development of biodegradable lactic polymers, which are eco-friendly and nontoxic. Lactic acid is the most important hydrocarboxylic acid with an asymmetrical carbon atom, widely distributed in nature, and it has shown great potential in fields of food, pharmaceutical, textile, leather and chemical industries. The aim of this doctoral thesis was to investigate the application of BSG in lactic acid production. First, the optimization of enzymatic hydrolysis of BSG was conducted, with the goal to achieve high reducing sugar concentrations, as much as possible, that are necessary on LA fermentation. BSG hydrolysis was conducted by usage of commercial enzymes for degradation of starch and cellulose. Effect of pH value, temperature and enzyme dosage on BSG hydrolysis efficiency was investigated. After the best conditions for BSG hydrolysis were determined, the optimized procedure for BSG hydrolysis was used for the production of BSG hydrolysate that will be used in LA fermentations. After optimization of BSG hydrolysis, LA fermentation by two LA producing microorganisms was investigated. The strains investigated were two LA bacteria strains: Lactobacillus fermentum PL-1 and Lactobacillus rhamnosus ATCC 7469. The effect of yeast extract (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%) addition in BSG hydrolysate, with the correction of pH value during LA fermentation by the addition of calcium-carbonate, on LA fermentation was investigated. Based on the results achieved for L-(+)- and D-(-)-LA ratio the LAB strains that produced more L-(+)-LA was chosen for further research. In further research the effect of pH correction (with addition of NaOH), yeast extract (0.5, 1.0, 2.0, 3.0, 4.0, and 5.0%) addition and reducing sugar concentration (2.7; 5.4 and 8.1%) in BSG hydrolysate on LA fermentation was investigated. Based on the results achieved the best yeast extract and reducing sugars concentrations was determined and used in further analysis or research. Also the possible replacement of expensive yeast extract and glucose with cheap alternatives, like brewer`s spent grain and stillage was investigated. The effect of brewer`s spent grain (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%), whole stillage (5, 10, 15 i 20%) and thin stillage (5, 10, 15, 20, 30, 40, 50%) addition before fermentation as well as thin stillage addition in fed-batch fermentation in BSG hydrolysate on LA fermentation were investigated. Also fed-batch fermentation procedure (addition of glucose, glucose and yeast extract and wort during fermentation) was investigated. The possible application of cells immobilized in Ca-alginate for LA fermentation of BSG hydrolysate was also investigated. Based on the results it was concluded that BSG can be successfully utilized as a raw material in production of LA, after optimization of hydrolysis and addition of nitrogen source. According to the results of chemical composition before and after optimized hydrolysis 78.6% of total cellulose was hydrolyzed. Addition of calcium-carbonate had positive effect on LA production by L. fermentum i L. rhamnosus. With the addition of calcium-carbonate reducing sugar utilization, LA yield and concentration and cell viability (both L. fermentum i L. rhamnosus) increased. Addition of calcium-carbonate and yeast extract had a positive effect on LA fermentation by L. fermentum and L. rhamnosus. In LA fermentation by L. fermentum the highest LA yield (44%) was achieved with addition of 5.0% of yeast extract and 2.0% of calcium-carbonate. In L. rhamnosus fermentations the highest total LA yield (98%) and L-(+)-LA yield (96%) was reached when 2.0% of yeast extract and 2.0% of calcium-carbonate were added. Based on the results achieved it was concluded that BSG hydrolysate, with the addition of yeast extract, is a good fermentation media for LA fermentation with L. rhamnosus, and it was decided that L. rhamnosus will be used in further research of LA fermentation on BSG hydrolysate. Addition of NaOH instead of calcium-carbonate for the pH correction shortened the fermentation time by 48 h and increased the L-(+)-LA volumetric productivity (by 200%, from 0.21 to 0.63 g/L·h-1). Based on this results pH correction in further experiments was done by addition of NaOH. In LA fermentation with different reducing sugar (2.7, 5.4 and 8.1%) and yeast extract concentrations (0.5-5.0%), the highest L-(+)-LA yield and volumetric productivity of 91.29%, and 1.69 g/L·h-1, respectively, as well as L. rhamnosus cell viability (9.67 log CFU/mL), were achieved with the reducing sugar content of 5.4% and yeast extract content of 5.0%. Based on this results in further experiment with the addition of stillage, in fed-batch fermentation and fermentation with immobilized cell BSG hydrolysate with 5.4% of reducing sugars and 5.0% yeast extract was used. In fermentation with the addition of brewer’s spent yeast the highest L-(+)-LA yield (89.01%) and volumetric productivity (0.89 g/L·h-1) were achieved in the fermentation of BSG hydrolysate with 5.0% of reducing sugar and 5.0% of brewer’s yeast. Based on the results achieved it was concluded that yeast extract can be partial or complete replaced by brewer’s spent yeast with significant decrease of media cost, without the decrease in LA fermentation efficiency. In fermentation with the addition of thin stillage the highest L-(+)-LA concentration, yield, and volumetric productivity of 31.03 g/L, 86.15%, and 0.93 g/L·h-1, respectively, was obtained in fermentation with the addition of 50% of thin stillage. The highest L-(+)-LA concentration, yield, and volumetric productivity achieved in fed-batch fermentation with the addition of glucose and thin stillage during fermentation, were 48,02 g/L, 87,82% i 0,96 g/L·h-1. In fed-batch fermentation the highest L-(+)-LA concentration, yield, and volumetric productivity of 116.08 g/L, 93.32%, and, 2.04 g/L h-1, respectively, were achieved in fermentation with glucose and yeast extract addition during fermentation. The results showerd that fed-batch fermentation could be used to increase L-(+)-LA fermentation efficiency Immobilization of L. rhamnosus cells with high viability (1010 CFU/mL) in Ca-alginate was conducted. Immobilized cells we successfully utilized in three repeated batch fermentation. L-(+)-LA yield and volumetric productivity were very high in all three batch fermentation, with the highest results achieved (95.20% and 1.76 g/L·h-1, respectively) in second fermentation. Application of immobilized L. rhamnosus cells increased L-(+)-LA yield and volumetric productivity and shortened the fermentation time for 12 h in comparison with batch fermentation

Brewer’s spent grain – raw material in lactic acid fermentation

Pivski trop čini približno 85% od ukupnih sporednih proizvoda proizvodnje piva, i dostupan je po veoma niskim cenama tokom čitave godine. Pivski trop ima veliku perspektivu za primenu u biotehnologiji i proizvodnji visoko vrednih proizvoda. Jedna od veoma ekološki i ekonomski isplativih alternativa je upotreba pivskog tropa u proizvodnji mlečne kiseline, jer se poslednjih par decenija uočava intenzivan rast potražnje za mlečnom kiselinom. Mlečna kiselina je najvažnija hidroksikarbonska kiselina široko rasprostranjena u prirodi, sa velikom primenom u prehrambenoj, farmaceutskoj, tekstilnoj i hemijskoj industriji i industriji prerade kože. Cilj istraživanja ove doktorske disertacije je ispitivanje primene pivskog tropa u proizvodnji mlečne kiseline. Prvo je izvršena optimizacija enzimske hidrolize pivskog tropa u cilju dobijanja što je moguće veće koncentacije redukujućih šećera neophodne za mlečno-kiselu fermentaciju. Hidrolizat pivskog tropa je dobijen enzimskom hidrolizom dodatkom komercijalnih enzima za razgradnju skroba i celuloze. Parametri čiji je uticaj na efikasnost enzimske hidrolize ispitanu su: pH vrednost, temperatura hidrolize i količina dodatih enzima. Nakon što su određeni najbolji uslovi razgranje pivskog tropa, dobijeni postupak hidrolize je primenjen u proizvodnji hidrolizata pivskog tropa koji je korišćen u mlečno-kiselim fermentacijama. Nakon toga je ispitana mlečno-kisela fermentacija sa dva proizvodna mikoorganizma. Kao proizvodni mikroorganizmi u mlečno-kiselim fermentacijama primenjena su dva soja bakterija mlečne kiseline: Lactobacillus fermentum PL-1 i Lactobacillus rhamnosus ATCC 7469. Ispitan je uticaj dodatka različitih koncentracija ekstrakta kvasca (0,5-5,0%) uz korekciju pH vrednosti tokom fermentacije sa dodatkom kalcijum-karbonata. U zavisnosti od udela L-(+)- i D-(-)-mlečne kiseline koje nastaju tokom fermentacije izabran je proizvodni mikroorganizam koji proizvodi više L-(+)-mlečne kiseline. U daljim ispitivanjima je ispitan uticaj korekcije pH pomoću natrijum-hidroksida kao i dodatak različitih koncentracija ekstrakta kvasca (0,5-5,0%) i redukujućih šećera (2,7; 5,4 i 8,1%) u hidrolizatu pivskog tropa na mlečno-kiselu fermentaciju pomoću odabranog soja bakterija mlečne kiseline. Na osnovu dobijenih rezultata izabrana je najbolja koncentracija redukujućih šećera i ekstrakta kvasca koji će se koristiti u daljim istraživanjima. Takođe je ispitana i mogućnost zamene skupog ekstrakta kvasca i glukoze sa obnovljivim sirovinama, kao što su pivski kvasac, džibra i bistra džibra. Ispitan je uticaj dodatka različitih koncentracija pivskog kvasca (0,5-5,0%), džibre (5-20%) i bistre džibre (5-50%) pre fermentacije kao i dodatak bistre džibre u dolivnoj fermentaciji, na mlečno-kiselu fermentaciju hidrolizata pivskog tropa. Ispitan je i dolivni postupak fermentacije hidrolizata pivskog tropa dodatkom glukoze, glukoze i ekstrakta kvasca i sladovine. Takođe je ispitana mogućnost izvođenja više uzastopnih fermentacija sa imobilisanim ćelijama odabranog soja bakterija mlečne kiseline u kalcijum-alginatu. Na osnovu eksperimentalnih rezultata zaključujeno je da je dodatak kalcijum-karbonata imao pozitivan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. Sa dodatkom kalcijum-karbonata povećali su se utrošak redukujućih šećera, koncentracija i prinos mlečne kiseline i vijabilnost ćelija L. fermentum i L. rhamnosus. Ekstrakt kvasca i kalcijum-karbonat su imali značajan uticaj na proizvodnju mlečne kiseline sa L. fermentum i L. rhamnosus. U fermentacijama sa L. fermentum najveći prinos ukupne mlečne kiseline (44%) je postignut sa dodatkom 5,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. U fermentacijama sa L. rhamnosus najveći prinos ukupne mlečne kiseline (98%) i L-(+)-mlečne kiseline (96%) je ostvaren u fermentaciji sa dodatkom 2,0% ekstrakta kvasca i 2,0% kalcijum-karbonata. Na osnovu rezultata odlučeno je da se u daljim ispitivanjima mlečno-kisele fermentacije hidrolizata pivskog tropa kao proizvodni mikoorganizam koristi L. rhamnosus. Primenom natrijum-hidroksida za korekciju pH je skratila fermentaciju za 48 sati a ostvareno je i značajno povećanje zapreminske produktivnosti L-(+)-mlečne kiseline (za 200%, povećanje sa 0,21 na 0,63 g/l·h-1). Korekcija pH u svim daljim istraživanjima je vršena sa dodatkom natrijum-hidroksida. U mlečno-kiselim fermentacijama sa različitim početnim koncentracijama redukujućih šećera (2,7; 5,4 i 8,1%) i sa dodatkom različitih koncentracija ekstrakta kvasca (0,5-5,0%), najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 91,29% i 1,69 g/l·h-1, kao i vijabilnost ćelija L. rhamnosus od 9,7·109 CFU/ml ostvareni su u fermentaciji sa početniom koncentracijom redukujućih šećera od 5,4% i dodatkom 5,0% ekstrakta kvasca. Na osnovu ostvarenih rezultata u istraživanjima sa dodatkom džibre i dodacima tokom fermentacije kao i u fermentacijama sa imobilisanim ćelijama je korišćen hidrolizat pivskog tropa sa početnom koncentracijom redukujućih šećera od 5,4%. U mlečno kiseloj fermentaciji sa dodatkom pivskog kvasca najveći prinos L-(+)-mlečne kiseline (89,01%) i zapreminska produktivnost (0,89 g/l·h-1) L-(+)-mlečne kiseline su ostvareni u fermentaciji sa dodatkom 5,0% pivskog kvasca i korekcijom početne koncentracije redukujućih šećera na 5,0%. Na osnovu rezultata utvrđeno je da se može izvršiti delimična ili potpuna zamena ekstrakta kvasca pivskim kvascem uz značajno smanjenje cene podloge za mlečno-kiselu fermentaciju, bez značajnog smanjenja efikasnosti mlečno-kisele fermentacije. U mlečno-kiseloj fermentaciji sa dodatkom džibre i bistre džibre najveć koncetracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline od 31,03 g/l, 86,15% i 0,93 g/l·h-1, ostvareni su u fermentaciji sa dodatkom 50% bistre džibre. Najviša koncentracija, prinos i zapreminska produktivnost L-(+)-mlečne kiseline ostvareni u dolivnoj fermentaciji sa dodatkom glukoze i bistre džibre tokom mlečno-kisele fermentacije su iznosili su 48,02 g/l, 87,82% i 0,96 g/l·h-1. U fermentacijama sa dodatkom nutritijenata tokom mlečno-kisele fermentacije najveća vrednost koncetracije, prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline od 116,08 g/l, 93,32% i 2,04 g/L·h-1, su ostvarene u fermentaciji sa dodatkom glukoze i ekstrakta kvasca tokom fermentacije. Na osnovu rezultata utvrđeno je da se dolivni postupak fermentacije može koristiti u cilju povećanja efikasnosti mlečno-kisele fermentacije. Izvršena je imobilizacija ćelija L. rhamnosus u kalcijum-alginatu uz izuzetno visoku vijabilnost (1010 CFU/ml). Imobilisane ćelije L. rhamnosus su uspešno korišćene u tri mlečno-kisele fermentacije. Prinos L-(+)-mlečne kiseline i zapreminska produktivnost su u sve tri fermentacije bili izuzetno visoki, pri čemu su najveći prinos L-(+)-mlečne kiseline i zapreminska produktivnost od 95,2% i 1,76 g/l·h-1, ostvareni u drugoj fermentaciji. Upotrebom imobilisanih ćelija L. rhamnosus je osim povećanja prinosa i zapreminske produktivnosti L-(+)-mlečne kiseline skraćena fermentacija za 12 sati u poređenju sa šaržnim fermentacijama.Brewers spent grain represents (BSG) about 85% of the total by-products from brewing process and is available at low price during the whole year. Due to its chemical composition BSG has great potential use in biotechnology and production of high-value products. One of very eco-friendly and economical alternative uses of BSG is in production of lactic acid (LA), since in the last few decades the demand for the LA has significantly risen, mostly because of development of biodegradable lactic polymers, which are eco-friendly and nontoxic. Lactic acid is the most important hydrocarboxylic acid with an asymmetrical carbon atom, widely distributed in nature, and it has shown great potential in fields of food, pharmaceutical, textile, leather and chemical industries. The aim of this doctoral thesis was to investigate the application of BSG in lactic acid production. First, the optimization of enzymatic hydrolysis of BSG was conducted, with the goal to achieve high reducing sugar concentrations, as much as possible, that are necessary on LA fermentation. BSG hydrolysis was conducted by usage of commercial enzymes for degradation of starch and cellulose. Effect of pH value, temperature and enzyme dosage on BSG hydrolysis efficiency was investigated. After the best conditions for BSG hydrolysis were determined, the optimized procedure for BSG hydrolysis was used for the production of BSG hydrolysate that will be used in LA fermentations. After optimization of BSG hydrolysis, LA fermentation by two LA producing microorganisms was investigated. The strains investigated were two LA bacteria strains: Lactobacillus fermentum PL-1 and Lactobacillus rhamnosus ATCC 7469. The effect of yeast extract (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%) addition in BSG hydrolysate, with the correction of pH value during LA fermentation by the addition of calcium-carbonate, on LA fermentation was investigated. Based on the results achieved for L-(+)- and D-(-)-LA ratio the LAB strains that produced more L-(+)-LA was chosen for further research. In further research the effect of pH correction (with addition of NaOH), yeast extract (0.5, 1.0, 2.0, 3.0, 4.0, and 5.0%) addition and reducing sugar concentration (2.7; 5.4 and 8.1%) in BSG hydrolysate on LA fermentation was investigated. Based on the results achieved the best yeast extract and reducing sugars concentrations was determined and used in further analysis or research. Also the possible replacement of expensive yeast extract and glucose with cheap alternatives, like brewer`s spent grain and stillage was investigated. The effect of brewer`s spent grain (0.5; 1.0; 2.0; 3.0; 4.0, and 5.0%), whole stillage (5, 10, 15 i 20%) and thin stillage (5, 10, 15, 20, 30, 40, 50%) addition before fermentation as well as thin stillage addition in fed-batch fermentation in BSG hydrolysate on LA fermentation were investigated. Also fed-batch fermentation procedure (addition of glucose, glucose and yeast extract and wort during fermentation) was investigated. The possible application of cells immobilized in Ca-alginate for LA fermentation of BSG hydrolysate was also investigated. Based on the results it was concluded that BSG can be successfully utilized as a raw material in production of LA, after optimization of hydrolysis and addition of nitrogen source. According to the results of chemical composition before and after optimized hydrolysis 78.6% of total cellulose was hydrolyzed. Addition of calcium-carbonate had positive effect on LA production by L. fermentum i L. rhamnosus. With the addition of calcium-carbonate reducing sugar utilization, LA yield and concentration and cell viability (both L. fermentum i L. rhamnosus) increased. Addition of calcium-carbonate and yeast extract had a positive effect on LA fermentation by L. fermentum and L. rhamnosus. In LA fermentation by L. fermentum the highest LA yield (44%) was achieved with addition of 5.0% of yeast extract and 2.0% of calcium-carbonate. In L. rhamnosus fermentations the highest total LA yield (98%) and L-(+)-LA yield (96%) was reached when 2.0% of yeast extract and 2.0% of calcium-carbonate were added. Based on the results achieved it was concluded that BSG hydrolysate, with the addition of yeast extract, is a good fermentation media for LA fermentation with L. rhamnosus, and it was decided that L. rhamnosus will be used in further research of LA fermentation on BSG hydrolysate. Addition of NaOH instead of calcium-carbonate for the pH correction shortened the fermentation time by 48 h and increased the L-(+)-LA volumetric productivity (by 200%, from 0.21 to 0.63 g/L·h-1). Based on this results pH correction in further experiments was done by addition of NaOH. In LA fermentation with different reducing sugar (2.7, 5.4 and 8.1%) and yeast extract concentrations (0.5-5.0%), the highest L-(+)-LA yield and volumetric productivity of 91.29%, and 1.69 g/L·h-1, respectively, as well as L. rhamnosus cell viability (9.67 log CFU/mL), were achieved with the reducing sugar content of 5.4% and yeast extract content of 5.0%. Based on this results in further experiment with the addition of stillage, in fed-batch fermentation and fermentation with immobilized cell BSG hydrolysate with 5.4% of reducing sugars and 5.0% yeast extract was used. In fermentation with the addition of brewer’s spent yeast the highest L-(+)-LA yield (89.01%) and volumetric productivity (0.89 g/L·h-1) were achieved in the fermentation of BSG hydrolysate with 5.0% of reducing sugar and 5.0% of brewer’s yeast. Based on the results achieved it was concluded that yeast extract can be partial or complete replaced by brewer’s spent yeast with significant decrease of media cost, without the decrease in LA fermentation efficiency. In fermentation with the addition of thin stillage the highest L-(+)-LA concentration, yield, and volumetric productivity of 31.03 g/L, 86.15%, and 0.93 g/L·h-1, respectively, was obtained in fermentation with the addition of 50% of thin stillage. The highest L-(+)-LA concentration, yield, and volumetric productivity achieved in fed-batch fermentation with the addition of glucose and thin stillage during fermentation, were 48,02 g/L, 87,82% i 0,96 g/L·h-1. In fed-batch fermentation the highest L-(+)-LA concentration, yield, and volumetric productivity of 116.08 g/L, 93.32%, and, 2.04 g/L h-1, respectively, were achieved in fermentation with glucose and yeast extract addition during fermentation. The results showerd that fed-batch fermentation could be used to increase L-(+)-LA fermentation efficiency Immobilization of L. rhamnosus cells with high viability (1010 CFU/mL) in Ca-alginate was conducted. Immobilized cells we successfully utilized in three repeated batch fermentation. L-(+)-LA yield and volumetric productivity were very high in all three batch fermentation, with the highest results achieved (95.20% and 1.76 g/L·h-1, respectively) in second fermentation. Application of immobilized L. rhamnosus cells increased L-(+)-LA yield and volumetric productivity and shortened the fermentation time for 12 h in comparison with batch fermentation

Informality and cultural landscape in Belgrade Riverside

By considering regulations defined by laws, plans and decisions on different levels related to urban development of Belgrade riverside, specific conditions of privatization of land, changes in legislation and insufficiently defined planning procedures have been recognized, which reflect the informal practice of land use development. The example of such coastal areas can be found along the Sava and Danube riverside, including the illegal appropriation of the aquatory, which are regarded in this research as a specific practice of creating a unique cultural landscape. This practice reflects a spontaneous urban development of the riverside through the formal and informal establishment of temporary and permanent housing, numerous commercial and recreational activities in different scale along the 200km of Belgrade riverbank. The shaping of the cultural landscape of Belgrade riverside will be analyzed through the comparison of the advantages and disadvantages of different approaches to the ongoing riverside urbanization, which manifest the complex linkage between formal institutions, and members of the local community. The importance of closer examination of cultural, economic, environmental and spatial aspects of this process is in the recognition of indigenous building regulations and relations to the natural resources. The main goal of the research is to understand different levels on which this informal practice persists and to outline the possibilities for the improvement of the current planning of Belgrade riverbank through their institutionalisation

Income convergence between Southeast Europe and the European Union

Ovaj rad analizira prosječnu bruto per capita dohodovnu konvergenciju osam zemalja Jugoistočne Evrope (JIE) prema prosjeku EU-a. Cilj je utvrditi koji faktori doprinose konvergenciji zemalja JIE regije kao i opisati kretanje konvergencije u periodu 2000.-2018. godine, s posebnom pozornošću na dva pod perioda, prije i nakon Svjetske ekonomke krize. Koristimo pri tome kombinaciju parametarskih i neparametarskih metoda i linearne panel regresije fiksnih efekata s robusnim standardnim greškama. Rezultati sugeriraju da je konvergencija bila podstaknuta procesom EU integracija, obrazovnim nivoom stanovništva, investicijama (stranim, domaćim i javnim), kreditnom ekspanzijom u privatnom sektoru, kao i rastom javnih rashoda. S druge strane, ekonomska kriza, nezaposlenost i inflacija bili su glavni faktori koji su utjecali na divergenciju procesa. Zaključujemo na kraju i da je post-tranzicijski model rasta dominantan u regiji SEE, temeljen na stranim direktnim investicijama, nedovoljan, i da su domaće privatne investicije kritično-nedostajući faktor brže dohodovne konvergencije.This paper investigates the average gross per capita income convergence of eight Southeast European economies towards the EU average. Our goal is to analyse which factors have driven that convergence in the SEE region and describe convergence paths in the 2000-2018 period, concerning two sub-periods, before and after the economic crisis. We use a combination of parametric and nonparametric methods and a fixed effects linear panel regression with robust standard errors. Results suggest that the EU integration process drove convergence, education level, investment (FDI, private domestic and public investments), and private sector lending, as well as by government expenditures. Economic crisis, unemployment, and inflation were the main factors which have influenced the divergence process. We also concluded that the post-transition growth model dominant in the SEE region, based on an FDI inflow, has not sufficient for income convergence in this region. Private domestic investments are a critical missing factor for faster income convergence

High-yielding and chemically enriched maize hybrids bred in Serbia - the best basis for super quality feed and food

Introduction/purpose: This paper presents the results of several different research studies. The inbred lines ZPPL 146 and ZPPL 159 and the maize hybrids ZP 633, ZP 735, and ZP 737 are primarily intended for human and livestock nutrition. Their selection took about four decades. Methods: Spectral bands were registered using the method of resonant Raman spectroscopy of the leaves of inbred maize lines. These spectral bands indicate the conformational characteristics of not only carotenoid molecules but also other compounds (phosphate, gluten, and amide III) in the leaf. Results: A systematic examination of the inbred lines ZPPL 146 and ZPPL 159 and their maize hybrids ZP 633, ZP 735, and ZP 737 was performed in this paper. It was stated that the new inbred lines of corn, i.e. ZPPL 146 and ZPPL 159, are rich in carotenoids and yellow pigments. These lines also have significant quantities of other valuable bioactive compounds and good physical characteristics. The lines have an upright position of the top leaves and belong to the group of maize lines with significant characteristics of the photosynthetic model. They are resistant to high temperatures and are drought tolerant. Conclusion: This paper presents the relevant properties, characteristics and parameters of the new studied inbred maize lines that can be used in selection processes in the future. High-yielding and high-quality maize hybrids, i.e. ZP 633, ZP 735, and ZP 737, have been created from the mentioned inbred maize lines. They are recognizable by their qualities. The hybrid ZP633 is especially noteworthy for human consumption (children and the elderly). Further, from the agronomic-veterinary point of view, it is confirmed that the hybrids ZP 735 and ZP 737 are the most suitable for livestock feeding with the programmed use of corn silage. The relevant agronomic, morphological and nutritional properties of the maize hybrids ZP 633, ZP 735, and ZP 737 are also presented in this paper. The results regarding the grain structure and yield height for grain and silage for the hybrids ZP 677 and ZP 684, produced in Serbia and the countries of Southeastern Europe, are also given

City Gallery at Kosančićev venac [Honorable Mention: DaNS 2018]

Uzimajući u obzir istorijsku stratifikaciju predmetne lokacije i zadate kompleksne uslove konkursa, prezentovani projekat Gradske galerije nastoji da uspostavi relaciju između tradicionalnih elemenata i savremenih principa arhitektonskog projektovanja i da naglasi identifikovane envajronmentalne vrednosti. Dvojaki, a opet istovremeni uticaji prirodnog i izgrađenog, uređenog i devastiranog, ali i težnje kako za zaštitom graditeljskog nasleđa tako i za potrebom za savremenim, definisali su podvojenost arhitekture galerije na dve oblikovne celine: arhitekturu tla i volumen programa.Taking into account the historical stratification of the site location and given complex competition requirements, presented project of the City Gallery strives to achieve the combination of traditional elements and modern principles in architectural design and to draw attention to the identified environmental values. Divers, yet simultaneous impacts of natural and constructed, decorated and devastated but also the aspirations to protect architectural heritage and the need to modernize it, defined the division in our design of the gallery: the architecture of the “ground” and “the volume of the program”

Povišenje nivoa šuma kod solarnih ćelija usled povišenja temperature i radijacionih oštećenja

Rad u otežanim uslovima kao što su povišena temperatura i zračenje mogu značajno pogoršati osnovne karakteristike fotodetektora (na primer solarnih ćelija). Iako mehanizmi i procesi degradacije mogu biti različiti, svi oni, manje ili vše, povećavaju nivo šuma u uređaju i povećavaju prag detekcije i ograničavaju funkcionisanje uređaja. To je veoma izraženo kod solarnih ćelija, zbog njihovog specifičnog dizajna i stalne izloženosti sunčevom zračenju. U ovom radu istraživanja su usmerena na analizu uticaja povišene temperature i radijacionih oštećenja na nivo šuma u solarnim ćelijama

Biological aspects of salivary hormones in male half-marathon performance

Physical effort is known to alter the blood levels of many hormones, but there are only a few studies about the biological changes of salivary hormones. The aim of this work was to determine whether salivary testosterone and salivary cortisol levels, measured two weeks before a half-marathon race, relate to running performance in male recreational athletes. A group of eleven male recreational athletes preparing for a half-marathon was included in the study. Saliva for testosterone and cortisol determinations was collected before and immediately after a 15-km training run, two weeks before the half-marathon. Individual official half-marathon times, expressed in hours, were used as a measure of performance. Mean testosterone concentrations were 1.07 +/- 0.33 nmol/l before the run and 0.88 +/- 0.35 nmol/l after the run (p lt 0.05). Mean cortisol concentrations were 12.28 +/- 8.46 nmol/l before the run and 38.08 +/- 19.63 nmol/l after the run (p lt 0.05). The pre-run salivary testosterone levels marginally correlated with the corresponding half-marathon running times (p=0.068, 95% bootstrap CI for slope -0.40 to -0.06). However, post-run salivary testosterone levels significantly correlated with the corresponding half-marathon running times (p=0.011, 95% bootstrap CI for slope -0.41 to -0.16), even considering correlations with the runners' age. Salivary cortisol levels, either pre- or post-run, did not correlate with the corresponding half-marathon running times. The results of this study suggest that post-exercise salivary testosterone levels could have the potential to predict performance in endurance running, at least in recreational athletes