77 research outputs found
Study of stacking interactions of the chelate rings in square-planar transition metal complexes
Nekovalentne interakcije aromatičnih i drugih π-sistema, uključujući steking
interakcije, su veoma važne u različitim molekulskim sistemima, od biomolekula do
kristalnog pakovanja.
U ovoj tezi je prvi put data evidencija o helat – helat steking interakcijama koje
su dobijene analizirajući kristalne strukture kvadratno – planarnih kompleksa prelaznih
metala iz Kembričke kristalografske banke podataka. Ova analiza je pokazala da helat –
helat steking interakcije postoje u velikom broju kristalnih struktura neutralnih
kvadratno – planarnih kompleksa. Geometrije ovih interakcija su slične geometrijama
steking interakcija aromatičnih organskih molekula.
Steking interakcije u kristalnim strukturama kvadratno-planarnih kompleksa u
kojima su helatni prstenovi kondenzovani sa C6H4 prstenovima su takođe analizirani.
Raspodela rastojanja između najbližih C6H4 – C6H4 i C6H4 – helat kontakata pokazuju
da je u velikoj frakciji intermolekulskih interakcija C6H4 prsten jednog molekula bliži
helatnom nego C6H4 prstenu drugog molekula.
Energije steking interakcija helatnih prstenova sa bilo kojim aromatičnim
prstenom do sada nisu bile poznate. U ovom radu, predstavljene su energije steking
interakcija acac-helatnih prstenova i benzena dobijene kvantno-hemijskim (ab initio i
DFT-D) izračunavanjima. Izračunate energije benzena i acac-kompleksa su u proseku
dva puta veće od energija dva molekula benzena.
Takođe su date procene helat – helat steking interakcija koristeći DFT-D metode
na sistemima [M(OC3H3O)(Cl)(CO)]2 (M = Ni, Pd, Pt) i [Pd(acac)(Cl)(CO)]2. Pokazalo
se da su helat – helat steking interakcije jače od helat – benzen interakcija i da energije
mogu da se kreću do 17 kcal/mol...Noncovalent interactions of aromatic and other π-systems, including stacking
interactions, are very important in various molecular systems, from biomolecules to
crystal packing.
In this thesis for first time it was given the evidence of chelate-chelate stacking
interactions obtained by analyzing crystal structures of square-planar transition-metal
complexes from the Cambridge Structural Database. This analysis showed that chelatechelate
stacking interactions occur in a large number of the crystal structures of neutral
square-planar complexes. Geometries of these interactions are similar to the geometries
of stacking interactions of organic aromatic molecules.
Stacking interactions in the crystal structures of square-planar complexes in
which chelate rings are fused with C6H4 rings were also analyzed. The distribution of
distances between the closest C6H4 – C6H4 and C6H4 – chelate contacts shows that in
large fraction of the intermolecular interactions C6H4-ring of one molecule is closer to
chelate than to C6H4-ring of the other molecule.
The energy of the stacking interaction of chelate rings with any aromatic ring is
not known. In this work, the energies of stacking interactions with benzene obtained by
the quantum chemical (ab initio and DFT-D) calculations are presented. The calculated
energies of stacking interactions of benzene with acac-complexes are an average two
times stronger that the stacking energy of two benzene rings.
Also energies of chelate – chelate stacking interactions were evalueated using
DFT-D methods on [M(OC3H3O)(Cl)(CO)]2 (M = Ni, Pd, Pt) and [Pd(acac)(Cl)(CO)]2
systems. It was shown that chelate – chelate stacking interactions are stronger than
chelate – benzene interactions with interaction energy up to 17 kcal/mol..
Ekonomska analiza integralne i organske proizvodnje voća
The introduction of environmentally friendly systems of fruit growing basically entails the conversion of intensive production to alternative production, which is much better for the environment. The optimal economic indicators are achieved in the integrated apple production. Therefore, high investments of labor and materials in this production enable very high production and economic results. High yields per unit area (exceeding 50 t/ha), which are achieved in the integrated apple production, can cover high investments per unit area. The maximum amount of variable costs (854,560 RSD/ha), the highest value of production (3,133,125 RSD/ha) and the gross margin (2,278,565 RSD/ha) have had a positive impact on achieving the highest efficiency (the cost-effectiveness ratio 3.12) in integrated production. On the other hand, this production has showed the lowest cost price per product unit (14.11 RSD/kg), which ensures significant competitiveness in apple production. .Uvođenjem ekološko prihvatljivih sistema voćarske proizvodnje, ustvari se vrši preorijentacija sa intenzivne proizvodnje na alternativne načine proizvodnje, koji su mnogo povoljniji po životnu sredinu. Najpovoljniji ekonomski pokazatelji se postižu u integralnoj proizvodnji jabuke. Naime u ovoj proizvodnji se sa visokim ulaganjem rada i materijala postižu veoma visoki proizvodno-ekonomski rezultati. Visoki prinosi po jedinici površine (i preko 50 t/ha) koji se postižu u integralnoj proizvodnji jabuke mogu da pokriju i visoka ulaganja po jedinici površine. Najveći iznos varijabilnih troškova (854.560 d/ha), najveća vrednost proizvodnje (3.133.125 d/ha ) i bruto marže (2.278.565 d/ ha) imali su pozitivnog uticaja na postizanje najveće ekonomičnosti (koeficijent ekonomičnost 3,12) u integralnoj proizvodnji. Sa druge strane, u ovoj proizvodnji je ostvarena i najniža cena koštanja po jedinici proizvoda ( 14,11 d/kg ), koja obezbeđuje značajnu konkurentnost u proizvodnji jabuke. . PR Projekat Ministarstva nauke Republike Srbije, br.(T-31058): Drying of organic and integrated fruits and vegetables by combined drying technology
Ostvareni finansijski rezultat u proizvodnji jagode kratkog dana
In South-western Ontario's continental climate (short days, hot summers and very cold winters) the matted-row system was the dominant production system to grow short-day strawberries. Varieties-staggered production (planting a combination of early, mid and late-season varieties) provides strawberry harvest from five to seven weeks. Short-day strawberries are vegetative grown in the first year, and harvested for two consecutive years. The total cost of short-day strawberry production was 54,370 CAD/ha and 16,930 CAD/ha (the first and second production years 41,330 CAD/ha, respectively). The short-day strawberries in matted-row system, with average yield of 15,722 kg/ha, generated a net revenue of 22,300 CAD/ha. Troškovi nege i berbe u prvoj godini iznose 20.812 CAD/ha, pri čemu učestvuju sa 69,42 % u strukturi ukupnih troškova zasnivanja i redovne proizvodnje jagode. Najniža ulaganja su pri zasnivanju zasada sa učešćem od 8,13%, dok je udeo troškova sadnje i nege zasada u ukupnim ulaganjima 22,45%. Ukupan prihod u proizvodnji jagode kratkog dana je 76.671 CAD u prvoj godini i 35.341 CAD/ha
Proizvodne karakteristike i ekonomski aspekti proizvodnje dunje
In spite of the very favorable natural conditions and modest requirements regarding the use of agricultural techniques for growing quince, it is very difficult to explain the fact that quince is very little represented in the fruit industry of Serbia as well as other countries. In the period 1999-2008, the quince was grown on average on the area of 57,557 ha in the whole world, while the realized production was 442,747 t. In the world, in Europe as well as in the Republic of Serbia, there is a tendency of increasing of both the quince growing area and its production. Although the number of fruitful trees has been decreasing in the Republic of Serbia (the change rate is -1.04%), the quince production has been increasing by an average annual change rate of 1.99%. The overall investment value of the intensive quince plantation amounts 3,630 €/ha. The planting cost of 1,490€/ha accounts for the greatest part (41.1%) in the overall cost of setting up a quince plantation. The realized profit, calculated as the difference between the production value and the production cost, amounts 8,580€/ha.I pored veoma povoljnih prirodnih uslova za njeno uspevanje i skromnih zahteva u pogledu primenjene agrotehnike, teško je objasniti malu zastupljenost dunje u voćarskoj proizvodnji, ne samo u Srbiji nego i u drugim zemljama. U proseku za period 1999-2008. godine površine dunje u svetu su iznosile 57.557 ha, a ostvarena proizvodnja 442.747 t. U svetu, Evropi i Republici Srbiji je ispoljena tendencija povećanja i površina i proizvodnje dunje. U Republici Srbiji i pored smanjenja broja rodnih stabala (stopa promene - 1.04%) ostvarena proizvodnja dunje se povećava po prosečnoj godišnjoj stopi promene od 1.99%. Ukupna investiciona vrednost intenzivnog zasada dunje iznosi 3.630 €/ha. Troškovi sadnje sa iznosom od 1.490 €/ha zauzimaju najveće učešće (41,1%) u ukupnim troškovima podizanja zasada dunje. Ostvarena dobit, izračunata kao razlika između vrednosti proizvodnje i troškova proizvodnje je 8.580 €/ha
Komparativna ekonomska analiza različitih sorti u integralnoj proizvodnji jabuke
Given that the choice of varieties depends significantly on the extent and quality of production, the paper made a comparative economic analysis of yield, production costs and the cost of four apple varieties (Gala, Braeburn and Golden Delicious Granny Smith) in integrated production. On average for the period 2008-2013 in the production of the analyzed apple cultivars largest financial result (profit ) was recorded in the variety Braeburn (1,166,980 RSD/ha). In the production of varieties Braeburn highest average yield (54,071 RSD/ha) and relatively low production costs (1,049,931 RSD/ha) were positively influenced the achievement of a satisfactory profit. The cultivar Braeburn financial result was almost doubles that of the variety Granny Smith. At the same time the cultivar Braeburn was detected and the lowest cost (20.24 $ /kg). In the analyzed production of varieties Gala total costs of production amounted to 1,009,787 L/ha. Labor costs in the amount of392,360 d/ha takes a share of38.85 % in the total cost. According to the representation in the total costs then comes cost of materials (23.13 %). The calculated cost is an average of 20.23 L/kg, with a variation of the observed age of 14.10 L/kg in 2011 to 34.43 kg/ha in the 2008th year.S obzirom da od izbora sorte značajno zavisi obim i kvalitet proizvodnje, u radu je sačinjena komparativna ekonomska analiza prinosa, troškova proizvodnje i cene koštanja za četiri sorti jabuke (Gala, Breburn Zlatni delišes i Greni smit) u integralnoj proizvodnji. U proseku za period 2008-2013. godine u proizvodnji analiziranih sorti jabuke, najveći fmansijski rezultat (profit) je ostvaren kod sorte Breburn (1.166.980 RSD/ha). U proizvodnji jabuke sorte Breburn najveći prosečan prinos (54.071 kg/ha) i relativno niski troškovi proizvodnje (1.049.931 RSD/ha) su pozitivno uticali na postizanje zadovoljavajućeg profita. Kod sorte Breburn ostvareni finansijski rezultat je skoro dvostruko veći u odnosu na sortu Greni Smit. Istovremeno kod sorte Breburn je konstatovana i najniža cena koštanja (20,24 RSD/kg). U analiziranoj proizvodnji sorte Gala ukupni troškovi proizvodnje su iznosili 1.009.787 RSD/ha. Troškovi rada sa iznosom od 392.360 RSD/ha zauzimaju učešće od 38,85 % u strukturi ukupnih troškova. Po zastupljenosti u ukupnim troškovima, zatim, dolaze troškovi materijala (23,13 %). Izračunata cena koštanja iznosi u proseku 20,23 RSD/kg, sa variranjimapo posmatranim godinama od 14,10 RSD/kg u 2011.godini do 34,43 kg/ha u 2008. godini
Komparacija ekonomskih pokazatelja različitih načina uzgoja višnje (Prunus cerasus L.) na porodičnom gazdinstvu
The research presented in this paper, the economic analysis of production of sour cherry on conventional and organic way. Based on survey data collected from growers sour cherry on family farms and professional technical and technological standard to all appropriate farming technologies, are prepared starting economic parameters. There identified investments in cherry plantation on an area per hectare. Then, they made calculations of average income and expenses for a representative year and based on their income statements prepared for the future exploitation of five years. With the application of static method calculated indicators of the economic feasibility of cherries. Were established the average net profit rate of accumulation, the period of return on capital in the production of cherries and others. And finally, there was a comparison of economic indicators at different ways of growing cherries, which is the primary goal of this research. Based on these results, it was concluded that the production of cherries profitable in both ways, whether favorable economic results achieved in organic compared to conventional production.Predmet istraživanja u ovom radu je ekonomska analiza proizvodnje višnje na konvencionalni i organski način. Na bazi prikupljenih podataka anketom od uzgajivača višnje na porodičnim gazdinstvima i stručnih tehničko-tehnoloških normativa za odovarajuće tehnologije uzgoja, sastavljeni su polazni ekonomski parametri. Utvrđena su investiciona ulaganja u podizanje zasada višnje na površini od 1 ha. Zatim, sastavljene su kalkulacije prosečnih prihoda i rashodi za reprezentatívne godine proizvodnje i na bazi njih sastavljeni bilansi uspeha za naredni period eksploatacije od pet godina. Uz primenu statičkih metoda, izračunati su pokazatelji ekonomske opravdanosti proizvodnje višnje. Utvrđeni su: prosečna neto dobit, stopa akumulativnosti, vremenski period povraćaja kapitala u proizvodnji višnje i dr. I na kraju, izvršena je komparacija ekonomskih pokazatelja pri različitim načinima uzgoja višnje, što je i osnovni cilj ovog istraživanja. Na osnovu dobijenih rezultata, zaključeno je, da je proizvodnja višnje na oba načina profitabilna, ali se povoljniji ekonomski rezultati postižu u organskoj u odnosu na konvencionalnu proizvodnju. I pored ispoljenih snaga, mogućnosti i slabosti u proizvodnji višnje u Republici Srbiji, najveće pretnje su, da se zbog visokih cena inputa za organski uzgoj, proizvođači mogu preusmeriti na konvencionalnu proizvodnju višnje, nedovoljna kontrola uvoza i 'gušenje ' domaće organske proizvodnje, pad platežne sposobnosti građana, a samim tim i tražnje za proizvodima organskog porekla, kao i nedovoljni podsticaji u sektoru prerade organskih proizvoda
Profitabilnost proizvodnje sušene šljive na porodičnoj farmi
In Serbia exists tradition of dried plums production. The production of dried plums on family farms is mainly seasonal (period of drying is maximum 1.5 months). Plant for production of dried plums on family farm capacity of drying 800-1000 kg per day of fresh plum can be profitable business, that employees family members during certain season. In year of beginning business family farm can expect loss off 3.732 € by scenario 'A', respectively loss off 980 € by scenario 'B'. However, in both of supposed scenario in the second year, after beginning of business can be expected real profit by about 10.000 € per year.U Srbiji postoji duga tradicija proizvodnje sušene šljive. Proizvodnja sušene šljive na porodičnim farmama je uglavnom sezonskog karaktera (period sušenja iznosi maksimalno 1,5 meseci). Pogon za proizvodnju sušene šljive na porodičnoj farmi kapaciteta sušenja 800-1.000 kg/dan sveže šljive, može biti profitabilan posao sa istovremenim zapošljavanjem članova porodične farme u toku određene sezone. U godini započinjanja biznisa porodična farma može očekivati gubitak od 3.732 € po scenariju "A", odnosno gubitak od 980 € po scenariju "B". Međutim, u oba pretpostavljena scenarija se u drugoj godini posle otpočinjanja biznisa može očekivati realna godišnja dobit od oko 10.000 €
Ekonomski uticaj ulaganja u proizvode sa dodatom vrednošću
Stone fruit plantations constitute more than two-thirds of all fruit plantations in Serbia (approximating to 67%), whereas plum plantations account for two-thirds of all stone fruit plantations in the country. Stone fruit production is commonplace in all parts of Serbia. There are large areas of extensive fruit plantations in Western Serbia and Šumadija (Valjevo, Kraljevo, Užice, Bajina Bašta and Kragujevac), whereas the largest fruit plantation areas are in the municipalities of Grocka, Smederevo, Prokuplje, Topola and Valjevo. Plum plantations are estimated to claim the biggest share of extensive fruit plantations in Serbia. A value chain is a powerful tool for increasing the added value of products. It represents a synthesis of activities carried out by a business organization in order to produce, pack, design, market, deliver and support its products. In the production of dried plums with stones, with an average production of 112 kg/day and an average selling price of 350 RSD/kg, the realized profit amounted to 18,237 RSD/day (for 24 hours of drying). With an average drying ratio of 4:1 (100 kg of fresh plums yield 25 kg of dried plums with a moisture content of 26 %), the added value of dried plums is increased approximately 6 times compared to fresh plums. According to the economic indicators calculated in the organic production of plums, a positive financial result (profit) of 3.940 €/ha was achieved. The cost price of plum production was 0.16 €/kg, and the selling price was 0.38€/kg. As the organic production of plums generates profit and the cost price per unit of measure is significantly lower than the purchase price of plums (0.16 €/kg lt 0.38 €/kg), the organic production of plums is economically justified for the producer.Preko dve trećine zasada voća u Srbiji čine koštičave voćne vrste (oko 67%), a u okviru toga, dve trećine otpada na šljivu. Proizvodnja koštičavih voćnih vrsta je zastupljena u svim delovima Srbije. U Zapadnoj Srbiji i Šumadiji se nalaze veće površine ekstenzivnih zasada (Valjevo, Kraljevo, Užice, Bajina Bašta, Kragujevac), a najveće površine pod plantažnim zasadima su u opštinama Grocka, Smederevo, Prokuplje, Topola i Valjevo. Procenjuje se da najveći udeo ekstenzivnih zasada u Srbiji čine zasadi šljive. Lanac vrednosti predstavlja snažan instrument za pronalaženje načina za stvaranje veće 'dodate' vrednosti za proizvode. Organizacija lanca vrednosti čini sintezu aktivnosti koje se obavljaju u cilju proizvodnje, pakovanja, dizajniranja, marketiranja, isporuke i podrške njenim proizvodima. U proizvodnji sušene šljive sa košticom, pri prosečnoj proizvodnji od 112 kg /dan i prosečnoj prodajnoj ceni od 350 din/kg, ostvarena dobit je iznosila 18.237 din/dan (za 24 sata sušenja). Pri prosečnom randmanu 1:4, odnosno ukoliko se od 100 kg sveže šljive može proizvesti 25 kg sušene šljive vlažnosti 26%, onda je dodata vrednost sušene šljive veća za oko 6 puta u odnosu na svežu šljivu. Prema ekonomskim pokazateljima utvrđenim u kalkulacijama u organskoj proizvodnji šljive postiže se pozitivan finansijski rezultat (dobitak) u iznosu od 3.940 €/ha. Cena koštanja šljive je 0,16 €/kg, a prodajna cena 0,38 €/kg. S obzirom da se u organskoj proizvodnji šljive postiže dobit, kao i da je cena koštanja po jedinici mere znatno niža u odnosu na prodajnu (otkupnu) cenu šljive (0,16 €/kg lt 0,38 €/kg) organska proizvodnja je ekonomski opravdana za proizvođača
Održivost organizaciono-ekonomskog modela lanca vrednosti organske maline
Of the total production of raspberries in Serbia, even 90 % is exported frozen to the EU market and in Germany, France, Holland, and Austria, and partly to the US market. The total European production of raspberries, Serbia participates with 20 %, and in domestic structure of fruit production from 6.5 %. According to the Ministry of Agriculture, Forestry and Water Management of the Republic of Serbia (2017), under organic production of fruit in Serbia is 1,527 ha, and the areas that are under conversion are located on 357 ha. In western Serbia is 198.94 ha under organic raspberries and 235.19 ha during conversion. Export from Serbia is 1,500 tons of organic raspberries annual which makes up 2 % of total production (and from conventional and organic production).Producers in the practice increasingly improve primary production and modernization of processing and marketing segments of raspberries. One of the concepts is the addition of economic value through organic products, products with protected designation of origin, branding, etc. This research starts from the hypothesis that it is economically profitable to invest in facilities to obtain products with added economic value. The research presented in this paper is a model organization purchase, processing and marketing of organic raspberries. The process of analysis is given on the basis of actual data company that operates in Arilje and brings together a larger number of producers of organic raspberries. By applying the methods of calculation and Cost-Benefit analysis were calculated economic indicators in the production of organic raspberries. Schematic shows the value chain, based on the SWOT analysis, recommendations for improvement and sustainability of such a model, as well as the possibility of its application to other production.Od ukupne proizvodnje maline u Srbiji, čak 90% se izvozi smrznuto na tržište EU i to u Nemačku, Francusku, Holandiju, i Austriju, a delom i na tržište SAD. U ukupnoj evropskoj proizvodnji maline, Srbija učestvuje sa 20%, a u domaćoj strukturi proizvodnje voća sa 6,5%. Prema podacima Ministarstva poljoprivrede, šumarstva i vodoprivrede Republike Srbije (2017), pod organskom proizvodnjom voća u Srbiji se nalazi 1.527 ha, a površine koje su u periodu konverzije nalaze se na 357 ha. U zapadnoj Srbiji se nalazi 198,94 ha pod organskom proizvodnjom maline i 235,19 ha u periodu konverzije. Godišnje se iz Srbije izveze do 1.500 tona organske maline što čini do 2% od ukupne proizvodnje, tj. i iz konvencionalne i organske proizvodnje. Proizvođači u praksi sve više unapređuju primarnu proizvodnju i modernizaciju segmenate prerade i plasmana maline. Jedan od koncepata predstavlja dodavanje ekonomske vrednosti kroz organske proizvode, proizvode sa zaštićenim geografskim poreklom, brendiranje, itd. Ovim istraživanjem se polazi od hipoteze da je ekonomski isplativo investirati u kapacitete za dobijanje proizvoda sa dodatom ekonomskom vrednošću. Predmet istraživanja u ovom radu je model organizacije otkupa, prerade i plasmana organske maline. Postupak analize je dat na bazi stvarnih podataka preduzeća koje posluje na području Arilja i okuplja veći broj proizvođača organske maline. Primenom kalkulativnih postupaka i Cost-Benefit analize, obračunati su ekonomski pokazatelji u proizvodnji organske maline. Šematski je prikazan lanac vrednosti, a na osnovu SWOT analize, date su preporuke za unapređenje i održivosti ovakvog modela, kao mogućnost njegove primene i na druge proizvodnje
Stacking interactions between chelate and phenyl rings in square-planar complexes of Cu, Ni, Pt and Pd
Previous analysis of geometrical parameters in the crystal structure of square-planar complexes, with and without chelate rings, of all transition metals from Cambridge Structural Database shows that there are stacking interactions between the phenyl ring and the chelate ring with delocalized -bonds. To investigate whether the type of metal atom influence this interaction we compare stacking parameters for the complexes with and without chelate rings in the complexes containing Cu(II), Ni(II), Pd(II) and Pt(II) metals. While the overall picture is similar for all four cases, complexes of Pd and Pt without chelate ring show tendency to form shorter contacts towards aromatic carbon. It was found that this behaviour is associated with the presence of cyano or isocyano derivatives as ligands.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
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