Basic principles of 3D concrete printing in the light of sustainable development

Although conservative, the construction industry must be transformed in line with new technologies. Adopting the concept of 3D printing can provide a handful of benefits in terms of creativity, flexibility, less waste generation, more efficient energy consumption as well as lower carbon emissions. The aim of this paper is to summarize the basic principles of 3d concrete printing, discussing the main goals and shortcomings that must be considered and resolved before wider application. Also, a review will be given on the production technology and materials used, as well as the sustainability of buildings built using the concept of 3d printing

The robustness of the differential quantizer in the case of the variable signal to noise ratio

In this paper a short theoretical overview of differential quantizer and its implementations is given. Afterward, the effect of the order of prediction in differential quantizer and the effect of the difference in order of predictor in the input and output of differential quantizer is analyzed. Then it was proceeded with the examination of the robustness of the differential quantizer in the case in which a noise signal is brought to the input of the differential quantizer, instead of the clean speech signal. The analysis was conducted with a uniform distribution, as well as the noise with the gaussian distribution, and the obtained results were adequately commented on. Also, experimentally a limit was set which refers to the intensity of the noise and still enable results which are better that a regular uniform quantizer. The whole analysis is done by using the fixed number of bits in quantization, i.e. 12-bit quantizer is used in all the implementations of differential quantizer. In the conclusion of this paper there is a discussion about the possibility of implementing a differential quantizer which will be able to recognize which noise attacks the system, and in addition to that, in what form it adapts its coefficients so that it at any moment acquires the optimal signal to noise ratio

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

Pesticides are recognized as an important source of potential pollution to soil and water due to their mobility and degradation in soils. Results presented in this paper show impact of the organic complex concentration on the adsorption of herbicides (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina, located near Boljevac municipality, was used for organic modification. Cationexchange capacity of this montmorillonite was determined by extraction with ammonium acetate (86 mmol/100g of clay). Montmorillonite have been modified first with NaCl and than with two organic complexes, hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). For both organic complexes, three saturation concentrations were selected for monitoring of the herbicide adsorption (43 mmol/100g of clay (0.5 CEC), 86 mmol/100g of clay (1 CEC) and 129 mmol/100g of clay (1.5 CEC)). Changes in the properties of the inorganic and organic bentonite have been examined using the X-ray powder diffraction (XRPD) andbatch equilibrium method. Increase in basal spacing (d) of montmorillonites saturated with 1.5 CEC of organic cation indicate that sorption of PTMA and HDTMA can exceed the saturation of 1 CEC. Both organic montmorillonites have shown higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, (presented in the form of log Kf and 1/n), it can be seen that the sorption decreases in the series: 0.5CEC> 1CEC> 1.5CEC> NaM, for both organic montmorillonites.Autor: Abstrakt na međunarodnoj konferencji EGU održanoj u Aprilu 2016 godine. Ne postoji hard copy knjige abstrakata

Adsorption behaviour of clomazone on inorganic and organically modified natural montmorillonite from Bogovina (Serbia)

The adsorption behaviour of the herbicide clomazone on inorganic and organically modified montmorillonite from the Bogovina deposit in Serbia was investigated. Montmorillonite was modified first with NaCl and then with organic complexes such as hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). Changes in the surface properties and morphology of the montmorillonite before and after the modification with various concentrations of organic complexes were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Adsorption of clomazone on all examined samples was investigated using the batch adsorption method. Montmorillonite modified with HDTMA-bromide displayed greater uptake of the clomazone compared to the PTMA-montmorillonite, and both organically modified montmorillonites displayed greater uptake of the herbicide compared to the inorganic montmorillonite. Comparing the Freundlich coefficient and maximum adsorbed clomazone quantity values obtained by Langmuir model, the levels of adsorption of clomazone decreased in the following order: HDTMA-montmorillonite with 1.00 cation-exchange capacity (CEC) saturation > HDTMA-montmorillonite with 0.75 CEC saturation > PTMA-montmorillonite with 1.00 CEC saturation > PTMA-montmorillonite with 0.75 CEC saturation > HDTMA-montmorillonite with 0.50 CEC saturation > HDTMA-montmorillonite with 0.25 CEC saturation > PTMA-montmorillonite with 0.50 CEC saturation > PTMA-montmorillonite with 0.25 CEC saturation > Na-montmorillonite > raw sample. The type and content of an organic cation plays an important role in the behaviour of clomazone in a solid/liquid system. It is concluded that organically modified montmorillonite from Bogovina might be used as an effective adsorbent for clomazone

Potential of humic acids and clays in the remediation of clomazonecontaminated environment

Klomazon (IUPAC: 2-(2-hlorobenzil)-4,4-dimetil-1,2-oksazolidin-3-on) je selektivni herbicid iz grupe izoksazolidinona, koji se na osnovu svojih fizičko-hemijskih karakteristika može svrstati u grupu pesticida koji predstavljaju potencijalne kontaminante površinskih voda, dubljih slojeva zemljišta i podzemnih voda. Glina i organska materija, pre svega huminske kiseline (HA), su glavne sorbujuće komponente zemljišta. Literaturni podaci ukazuju da u sorpciji klomazona u zemljištu učestvuje ili organska materija [1-3]ili glina i organska materija [4,5]. S toga je cilj ovog radabio ispitati potencijal HA i glina izdvojenih iz različitih tipova poljoprivrednog zemljišta sa područja Republike Srbije (rendzina, černozem i smonica) u sorpciji klomazona, odnosno odrediti njihov remedijacioni potencijal. Za proučavanje sorpcionog ponašanja klomazona i određivanje njegovih sorpcionih konstanti (Kd) za pomenute supstrate je korišćen batch metod [6], zasnovan na ravnotežnoj raspodeli molekula klomazona u sistemu supstrat/vodena faza. U slučaju HA, sistem se sastojao od smeše 25 mg supstratai 2,5 mL rastvora određene koncentracije (0,5 – 25 g/mL)klomazona u 0,01 M CaCl2, dok je u slučaju glina sistem sadržao 250 mg gline i 2 mL pomenutih rastvora. Svaka smeša je homogenizovana 24 h radi dostizanja ravnotežne raspodele ovog jedinjenja između dve faze sistema. Nakon centrifugiranja, vodena faza je analizirana HPLC-om opremljenim sa PDA detektorom, pri čemu su Kd koeficijenti klomazona za proučavane supstrate računati kao odnos koncentracije pesticida koja je sorbovana za supstrat (Cs) i koncentracije jedinjenja koja je zaostala u vodenoj fazi (Ce), u uslovima ravnotežne raspodele. Adsorpcione izoterme su dobijene primenom Frojndlihove jednačine na eksperimentalno dobijene rezultate, pri čemu su Frojndlihovi koeficijenti Kf i n, dobijeni primenom linearne forme Frojdlihove jednačine. Dobijeni rezultati ukazuju da je sorpcija klomazona mnogo veća za HA nego za gline, i da opada u sledećem nizu: HA, rendzina (Kd=114,02 mL/g) >HA, smonica (Kd=97,71 mL/g) >HA, černozem (Kd=91,24 mL/g)>> glina, smonica (Kd=2,29 mL/g)> glina, černozem (Kd=2,16 mL/g)>glina, rendzina(Kd=1,61 mL/g). Da je sorpcija klomazona za HA znatno veća nego za gline, ukazuju i vrednosti Frojndlihovih Kf koeficijenata, koji za pomenute supstrate imaju sledeće vrednosti: Kf=188,63 (HA, rendzina), Kf=170,61 (HA, smonica), Kf=167,19 (HA, černozem), Kf=1,80 (glina, černozem), Kf=1,10 (glina, rendzina) i Kf=0,98 (glina, smonica). Dobijene vrednosti Frojndlihovih 1/n koeficijenata ukazuju da su izoterme dobijene za sve analizirane HA Ltpa (0,767, 0,698 i 0,708 za HA poreklom iz zemljišta tipa rendzina, černozem i smonica, redom), što ukazuje na snažnu sorpciju molekula klomazona za sorpcione centre analiziranih HA pri nižim koncentracijama pesticida, pri čemu ona opada kako koncentracija jedinjenja raste. Sa druge strane, izoterme dobijene za gline poreklom iz rendzine i smonice (1/n=1,146 i 1,342, redom) su tzv. S-tipa, što ukazuje na slabiju adsorpciju klomazona za sorpcione centre supstrata pri nižim koncentracijama pesticida u sistemu, nakon čega se sorpcija pojačava, da bi pri većim količinama pesticida u sistemu, ona opet počela da se smanjuje (postepena saturacija sorpcionih centara supstrata). Izoterma dobijena za glinu izdvojenu iz zemljišta tipa černozem (1/n=1,074) je C-tipa i karakteriše je linearna zavisnost između sorbovane količine klomazona i količine ovog pesticida koja zaostaje u rastvoru u sistemu glina/voda. Prikazani rezultati ukazuju da HA imaju dobar sorpcioni potencijal za klomazon, odnosno da se mogu koristiti za remedijaciju zemljišta i različitih vodenih sistema kontaminiranim klomazonom. Dodatne FTIR analize treba da pokažu koje funkcionalne grupe HA i glina su odgovorne za vezivanje molekula klomazona i samim tim objasne razlike u veličini sorpcije između različitih HA i glina poreklom iz različitih zemljišta