Spectrometer with CCD detector

Spektrometar sa CCD detektorom kompaktna je varijanta spektrometra s difrakcijskom rešetkom, bez pomičnih dijelova koje inače sadrži svaki „klasični“ spektrometar. U ovom spektrometru difrakcijska je rešetka nepomična, a spektar se registrira na CCD detektoru linearnog tipa. U prvom dijelu rada bit će objašnjena teorijska podloga spektrografije. Nakon toga bit će objašnjen princip rada jednostavnih spektrografskih ureĎaja, uz odvojeni osvrt na različite tipove detektora. Na primjeru će biti prikazano kako radi USB spektrometar te će se njime istražiti neki tipični spektri. U posljednjem, metodičkom dijelu rada, bit će istražena mogućnost konstrukcije jednostavnog priručnog spektrometra. Uz vrlo nisku cijenu kombiniranu s jednostavnom izradom, ovakav spektrometar moguće je lako konstruirati te primijeniti u školskoj nastavi.Spectrometer with a CCD detector is a compact version of a diffraction grating spectrometer, without any movable parts that can normally be found in a „classic“ spectrometer. In this spectrometer, the diffraction grating is non-movable, and the spectrum is measured on a linear CCD detector. In the first part of this thesis we will explain the basic theoretical background of spectrography. After that we will explain the basic operation of typical spectrographic devices, with a separate part dedicated to different types of detectors. We will also show how a USB spectrometer is operated and explore the spectra of some typical sources. In the last, educational part of this thesis, we will consider the possibility of constructing a simple hand-held spectrometer. With an extremely low price combined with a simple construction, this type of spectrometer could easily be assembled and used in schools

The Role of the Nutrition in the Pathogenesis of Gastroesophageal Reflux Disease, Barrett’s Oesophagus and Oesophageal Adenocarcinoma

This paper aims at evaluating the role of improper nutrition in the pathogenesis of gastroesophageal reflux disease (GERD), Barrett’s oesophagus (BE), and oesophageal adenocarcinoma (EADC). It also tries to examine the influence of the alcohol, nicotine and coffee consumption in the development of the mentioned diseases. There were 180 subjects included in the trial, 109 males and 71 females, which were divided in the four groups (70 patients with GERD, 20 patients with BE, 20 patients with EADC, and 70 healthy examinees composing a control group). Their dietary habits were investigated by the usage of the dietary questionnaires. The results show that the fast eating and the insufficient mastication were present in 64.3–85.0% patients with GERD, BE, and EADC in comparison with only 15% of the examinees from the control group. Furthermore, very hot was preferred by 25.0–42.9% of the mentioned patients in comparison with only 12.9% from the control group. Similarly, 60.0–75.0% of them preferred strongly spiced food on contrary with 17.1% of the healthy examinees. Moreover, strong alcoholic beverages were consumed three or more times per week by 55.0–75.0% of the mentioned patients in comparison with only 15.7% from the control group. Finally, there were 15.7–55.0% heavy smokers among the patients with GERD, BE, and EADC contrary to 1.4% in the control group

Analysis of recycling possibilities of discontinuous E-glass fibres

Pri tkanju staklenih vlakana obrezuju se rubovi širine od 40 do 60 mm i bacaju na odlagališta otpada. Ti se rubovi sastoje od rovinga koji su povezani s nekoliko okomito orijentiranih pamučnih niti. Radi smanjivanja količine otpada analizirana je mogućnost recikliranja tako nastalih diskontinuiranih E-staklenih vlakana. Istraživanje nije usmjereno na konkretan proizvod, nego na mogućnost priprave kompozita s dodanim vlaknima. Ispitane se mogućnosti pripreme i utjecaj vlakana na svojstva sintetskih organskih polimera, betona, morta i asfalta.By interweaving direct rovings, 40–60 mm wide edges of the fabrics are being cut as waste. With the aim of reducing waste accumulation, several possibilities of recycling discontinuous E-glass fibres have been studied. The intention of the study was not to develop a particular product, but to test the possibilities of materials preparation when discontinuous glass fibres are added. The fibres are added to synthetic organic polymers, concrete, mortar and asphalt and their influence on materials properties was tested

Inventorying of fruit species and ornamental arboreal plants in private gardens in the city of Knin

U radu se iznose rezultati istraživanja ukrasne dendroflore i voćnih vrsta privatnih vrtova na području grada Knina, koji je smješten u sjevernoj Dalmaciji, na padinama brda Spas, u Šibensko-kninskoj županiji na području ukupne površine od 355 km2. Tijekom florističkog istraživanja od ožujka do svibnja 2014. godine u predgrađu Knina zvanom „Pejton“ (istočno od kninske vojarne), analizirano je 90 privatnih vrtova različite veličine te je zabilježeno 58 svojti iz 27 porodica. U privatnim vrtovima dominiraju kritosjemenjače (47 svojti; 81,03 %), među kojima su dvosupnice (45; 77,59 %) u većoj mjeri zastupljenije od jednosupnica (2; 3,45 %). S najvećim brojem vrsta ističe se porodica Rosaceae (15 vrsta; 25,86 %). S obzirom na tip habitusa (po Erhardt i sur., 2002.) dominiraju grmolike formi (29 svojti; 50 %), potom slijede stabla (25 svojti; 43,10 %), polugrmovi (1 svojta; 1,72 %) i penjačice (3 svojte; 5,17 %). Listopadne svojte (30; 51,72 %) su zastupljenije od zimzelenih (28; 48,27%). Među 18 autohtonih svojti (31,03 %) dominiraju vrste koje dolaze u uzgoju (13 svojti; 22,41 %) Kod alohtonih svojti dominiraju vrste koje isključivo dolaze u kulturi (32 svojti; 55,17 %), slijede neudomaćene svojte „casual“-cas (7; 12,07 %), te jedna invazivna svojta (1,72 %). Analiza alohtone dendroflore prema geografskom podrijetlu pokazuje najveću zastupljenost biljaka azijskog podrijetla (23; 39,65 %), zatim slijede svojte iz Amerike (9; 15,52 %), Europe i Azije (8; 13,79 %). U krajobrazno uređenje privatnih vrtova potrebno je uvoditi naše autohtone dendrološke ukrasne i voćne vrste, a u vrtovima su većinom korištene alohtone vrste koje se uzgajaju zbog dekorativnosti te utilitarnog karaktera.This paper presents results on research of ornamental arboreal plants and fuit species of private gardens in Knin area, in north Dalmatia, on the slopes of "Spas" hill, in the Šibenik-Knin county, occupying a total area of 355 km2. During floristic research from March to May 2014 in Knin suburbs called "Pejton" (east of Knin military barracks), 90 private gardens of different sizes were analyzed and 58 families from 27 classes were registered. Magnoliophyta dominate in private gardens (47 families; 81,03 %), among which Dicotyledons (47; 77.59 %) are more common than Monocotyledons (2; 3.45 %). The family Rosaceae (15 families; 25.86 %) stands out with the largest number of species. Considering the type of habitat (Erhardt et al., 2002) bushlike forms dominate (29 families; 50 %). They are followed by trees (25 families; 43.10 %), halfbushes (1 familiy; 1.72 %) and climbing plants (3 families; 5.17 %). Deciduous families (30; 51.72) are more represented than evergreen families (28; 48.72 %). Among 18 autochthonous families (31.03 %) cultivated species (13 families; 22,41 %) dominated. Species that are cultivated dominate amnong alochthonous species (32 families; 55.17 %). They are followed by non-domesticated species "casual-cas" (7; 12.07 %) and one invasive family (1.72 %). Analysis of alochthonous dendroflora according to geographical origin shows that the most representative are plants of Asian origin (23; 39.65 %), followed by families from America (9; 15.52%), Europe and Asia (8; 13.79 %). It is necessary to use more of our autochthonous dendrological ornamental and fruit species in landscaping of private gardens, while alochthonous species are mostly grown in gardens because of their decorative and utilitaryian character

Karakterizacija izotermički poboljšanog nodularnog lijeva

U ovom radu opisan je postupak poboljšavanja mehaničkih i triboloških svojstava izotermički poboljšanog nodularnog lijeva (ADI) primjenom postupka površinskog kugličarenja. U eksperimentalnom dijelu rada ispitana je otpornost na abrazijsko i erozijsko trošenje u svrhu utvrđivanja utjecaja kugličarenja na površinska svojstva izotermički poboljšanog nodularnog lijeva. U tu svrhu provedena je analiza mikrostrukture i mjerenje mikrotvrdoće. Utvrđeno je da se postupkom kugličarenja povećala površinska tvrdoća materijala i poboljšala otpornost na abrazijsko trošenje ali nije bilo utjecaja na otpornost prema eroziji česticama

Inventorying of fruit species and ornamental arboreal plants in private gardens in the city of Knin

U radu se iznose rezultati istraživanja ukrasne dendroflore i voćnih vrsta privatnih vrtova na području grada Knina, koji je smješten u sjevernoj Dalmaciji, na padinama brda Spas, u Šibensko-kninskoj županiji na području ukupne površine od 355 km2. Tijekom florističkog istraživanja od ožujka do svibnja 2014. godine u predgrađu Knina zvanom „Pejton“ (istočno od kninske vojarne), analizirano je 90 privatnih vrtova različite veličine te je zabilježeno 58 svojti iz 27 porodica. U privatnim vrtovima dominiraju kritosjemenjače (47 svojti; 81,03 %), među kojima su dvosupnice (45; 77,59 %) u većoj mjeri zastupljenije od jednosupnica (2; 3,45 %). S najvećim brojem vrsta ističe se porodica Rosaceae (15 vrsta; 25,86 %). S obzirom na tip habitusa (po Erhardt i sur., 2002.) dominiraju grmolike formi (29 svojti; 50 %), potom slijede stabla (25 svojti; 43,10 %), polugrmovi (1 svojta; 1,72 %) i penjačice (3 svojte; 5,17 %). Listopadne svojte (30; 51,72 %) su zastupljenije od zimzelenih (28; 48,27%). Među 18 autohtonih svojti (31,03 %) dominiraju vrste koje dolaze u uzgoju (13 svojti; 22,41 %) Kod alohtonih svojti dominiraju vrste koje isključivo dolaze u kulturi (32 svojti; 55,17 %), slijede neudomaćene svojte „casual“-cas (7; 12,07 %), te jedna invazivna svojta (1,72 %). Analiza alohtone dendroflore prema geografskom podrijetlu pokazuje najveću zastupljenost biljaka azijskog podrijetla (23; 39,65 %), zatim slijede svojte iz Amerike (9; 15,52 %), Europe i Azije (8; 13,79 %). U krajobrazno uređenje privatnih vrtova potrebno je uvoditi naše autohtone dendrološke ukrasne i voćne vrste, a u vrtovima su većinom korištene alohtone vrste koje se uzgajaju zbog dekorativnosti te utilitarnog karaktera.This paper presents results on research of ornamental arboreal plants and fuit species of private gardens in Knin area, in north Dalmatia, on the slopes of "Spas" hill, in the Šibenik-Knin county, occupying a total area of 355 km2. During floristic research from March to May 2014 in Knin suburbs called "Pejton" (east of Knin military barracks), 90 private gardens of different sizes were analyzed and 58 families from 27 classes were registered. Magnoliophyta dominate in private gardens (47 families; 81,03 %), among which Dicotyledons (47; 77.59 %) are more common than Monocotyledons (2; 3.45 %). The family Rosaceae (15 families; 25.86 %) stands out with the largest number of species. Considering the type of habitat (Erhardt et al., 2002) bushlike forms dominate (29 families; 50 %). They are followed by trees (25 families; 43.10 %), halfbushes (1 familiy; 1.72 %) and climbing plants (3 families; 5.17 %). Deciduous families (30; 51.72) are more represented than evergreen families (28; 48.72 %). Among 18 autochthonous families (31.03 %) cultivated species (13 families; 22,41 %) dominated. Species that are cultivated dominate amnong alochthonous species (32 families; 55.17 %). They are followed by non-domesticated species "casual-cas" (7; 12.07 %) and one invasive family (1.72 %). Analysis of alochthonous dendroflora according to geographical origin shows that the most representative are plants of Asian origin (23; 39.65 %), followed by families from America (9; 15.52%), Europe and Asia (8; 13.79 %). It is necessary to use more of our autochthonous dendrological ornamental and fruit species in landscaping of private gardens, while alochthonous species are mostly grown in gardens because of their decorative and utilitaryian character

Impact of Microplastics on the Fate and Behaviour of Arsenic in the Environment and Their Significance for Drinking Water Supply

The ubiquitous presence of microplastics (MPs) is a topic of great concern. Not only do MPs themselves represent potential toxicants for human health, they are never found alone in the environment and interact with and adsorb a variety of toxicologically significant pollutants. This review summarises recent work on interactions between MPs and heavy metals in the environment, with a special focus on arsenic, one of the most widespread and problematic water contaminants. Evidence for the adsorption of arsenic onto MP surfaces is given and the recent research into the consequences of this phenomenon for freshwater, marine, and soil environments presented. Finally, the lack of research into the significance of interactions between arsenic and MPs during drinking water treatment is highlighted. The performance of arsenic removal technologies is governed by a multitude of different factors, and with MPs detected in water sources all over the world, data on how these MPs impact the removal of arsenic and, indeed, other major water contaminants are urgently needed

Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L−1) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the pH of the solutions from pH 2 to pH 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient KF) ranging from 1.24 to 13.2 (mg g−1)/(mg l−1)n, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions