This work provides insight into possibilities of maximum utilization of C3-C4 energy crops for thermo-chemical conversion (slow pyrolysis) into high value biochemicals, platform chemicals, drop-in ...fuels and combustible gases, using coupled kinetic and thermodynamic analyses. In order to examine the kinetics of decomposition of lignocellulosic components, model-free and model-based methods faded from thermal analysis data were used. Thermodynamic compensation was used for explicatory of entropy controlled process, where conformational changes and chemical exchange directly affect the type and distribution of obtained pyrolytic products. It was shown that external variable (i.e. the heating rate/temperature) does not change either an entire reaction mechanism (mechanistic nature of MG and AD pyrolyses) or transition state, but it changes activation enthalpy and activation entropy which lead to differences in terms of heat energy consumption, pyrolysis favorability and thus rates of generation of activated complex among feedstocks. To investigate the interplay of catalysts (present in feedstocks as minerals) and reactants, selective energy transfer (SET) model was applied. The model showed an activity of catalyst with different outputs towards two reactants, lignin part of the structure in MG and 1,8-cineole in AD. It was shown that AD is more convenient for thermal conversion than MG, regarding to lower transformation energy requirement, higher reactivity, as well as much faster accumulation of products.
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•Enthalpy-entropy compensation is a source of KCE for perennial grasses slow pyrolysis.•Pyrolysis is strongly influenced by disorder level (entropy driven) during conversion.•Pyrolysis favorability is lower for Miscanthus×giganteus-MG than for Arundo donax-AD.•AD has high reactivity accumulating more products (bio-oils and high value chemicals).•Applied selective energy transfer model shows interplay of the catalyst and reactant.
•Miscanthus giganteus and Arundo donax are characterized by high volatilization.•Difference between reaction temperatures is affected by composition of energy crops.•Arundo donax has higher exergy ...efficiency of syngas based on CH4 production.•Arundo donax has the lower biomass chemical exergy compared to Miscanthus giganteus.•The lower equivalance ratio produces higher exergy efficiency of the gasification.
The actual paper analyses the performance of different energy crop biomasses, Miscanthus x giganteus Greef et Deu (EC-1) and Arundo donax L. (EC-2) stems, during slow pyrolysis process monitored by simultaneous TG-DTG-MS techniques, through chemical exergy analysis. In addition to considering the physical and chemical characteristics of given feedstocks for their efficient thermo-chemical conversion into pyrolytic gas, in this study, a theoretical simulation for their implementation use in the gasification process was also performed. The performed thermodynamic study with detailed exergy analysis showed that the large contribution of exergy in syngas components such as CO and H2 originates primarily from cellulose pyrolysis of EC-1, while large exergy contribution in syngas component as CH4 originates from lignin pyrolysis of EC-2. It was founded that the exergy efficiency of syngas for EC-1 equals 19.04%, which is lower than the exergy efficiency of syngas for EC-2 (20.46%), as a result of higher ash content in EC-1. Also, it was reported that higher carbon (C) and hydrogen (H) contents present in the EC-2 sample generate higher gaseous energy and exergy values, i.e. the increment of exergy efficiency of syngas, by both approaches (pyrolysis and gasification exergy analysis), but results in a lower biomass chemical exergy (18.28 MJ kg−1). The methodology applied to the gasification process was shown a higher exergy efficiency for EC-2 (∼36 – 42%) than for EC-1 (∼33 – 39%), dependant on the equivalence ratio (ER).
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As one of the most promising groups of microbes, lactic acid bacteria (LAB) can synthesize metabolites that can be used in different industries over the world, mainly in the pharmaceutical, food, and ...dairy industries. In this study, a novel exopolysaccharide was extracted and isolated from the probiotic strain
Lactobacillus reuteri
B2, and assessed on biological activity and its possible application as a biosorbent for the removal of Ni
2+
ions from contaminated water. New exopolysaccharide was characterized using FTIR, SEM, XRD, NMR, MALDI-TOF MS, and TGA/DTG analysis. Biological assays included antioxidative activity, cytotoxic assay, and adhesion assay of
L. reuteri
B2 to HT29 cells. Our hypothesis was that if this exopolysaccharide is nontoxic, it can be used as a novel biomaterial for the possible application of the removal of Ni
2+
ions from contaminated water. The scavenging effect of nontoxic exopolysaccharide was 76% at 2 mg/mL using ABTS assay, in biological assays, while the removal efficiency of nickel from the aqueous solution was 92.96% in biosorption study. According to these results, this exopolysaccharide can be considered a very promising biomaterial for potential application in different industries, from pharmacy to wastewater treatments.
Graphical abstract
Biogas is a sustainable and renewable energy source that can provide green energy, a better environment and new jobs. The aim of this paper is to present potentials for biogas production in the ...Republic of Serbia from different sources (agricultural crops directly provided for energy, livestock residues, municipal solid waste, slaughterhouse waste and wastewater from milk processing industry) and to analyze the current situation in this sector in Serbia. The barriers that limit the wider production of biogas are considered. Results have shown that there is a great potential for biogas production in Serbia. The yearly potentials were calculated as follows: biogas production potential from agricultural crops directly cultivated for energy is 0.85 Mega tons of oil equivalent (Mtoe); potential from livestock residues amounts to 94.13ktoe; potential from municipal solid waste (MSW) is 49.72ktoe; potential from slaughterhouse waste is 9.94ktoe and potential from milk processing industry is 3.21ktoe. The analysis of incentives, barriers and status of biogas technologies presented in this paper represents a contribution for the further improvement and analysis of the biogas sector in the Republic of Serbia.
Emulsification followed by freezing and thawing cycles was applied to produce poly(vinyl alcohol) (PVA) microparticles and to simultaneously immobilize activated sludge. Activity of the obtained ...microparticles (∼400 μm in diameter) was evaluated in glucose syrup solutions and heat-pretreated wastewater from a starch factory by measurements of permanganate index (COD
Mn
) reduction. The reaction followed first-order kinetics, revealing slight mass transfer limitations in PVA microparticles as determined from the kinetic rate constant that was ∼35% lower than that in the freely suspended activated sludge culture. Yet, efficiency of the microparticles increased almost five-fold in a laboratory airlift bioreactor operating either in batch or continuous regimes. Over 19 days of operation under high organic loadings in the industrial wastewater (∼100 kg
COD
m
−3
d
−1
), PVA microparticles (12.4% volume fraction) remained active and induced a decrease of over 90% of biodegradable COD
Mn
at the hydraulic retention time of 8 h.
The aim of this paper is to determine the current situation in the field of geographical indications schemes (GI), obstacles for futures development and to provide recommendations for GIs development ...in Serbia, Bosnia and Herzegovina and Montenegro. GIs quality schemes provide confirmation to consumers that foodstuff is a traditional product produced in a certain area and with certain attributes. Although the Western Balkan countries are reach in well-known traditional products and have excellent ago-ecological conditions for GIs production, this quality schemes are not developed. In this paper are applied comparative methodology, literature review and field research. Results are showing that path to improvement GIs is in the further legal framework harmonization with EU legal framework, providing flexibility for registration of the GIs foodstuff processing capacities, support to the producer's organization, shifting of the national GIs recognition to the EU, systematic support to the GIs etc.
Left-sided inferior vena cava (LIVC) and duplicated inferior vena cava (DIVC) are rare asymptomatic congenital abnormalities. Unrecognized, these anomalies can be the source of major injuries and ...cause serious life-threatening bleeding complications especially during abdominal aortic surgery.
Retrospective data for patients with 2 major inferior vena cava (IVC) anomalies that underwent aortic surgery over a 13-year period were collected. Patient demographics, type of aortic disease and caval anomaly, surgical approach, type of aortic reconstruction associated with procedure on caval vein, postoperative complications, and in-hospital mortality were recorded.
There were 9 patients with inferior vena cava (IVC) anomalies who underwent aortic surgery. All of them were men, with a median age of 66.2 years. Seven had an LIVC and 2 had DIVC. Five patients were operated on due to abdominal aortic aneurysm and 4 due to aortoiliac occlusive disease. In all patients, a midline transperitoneal aortic approach was performed. In 5 cases, the left IVC had to be temporarily resected and later reconstructed, and in the other 4 it was just mobilized. There were no postoperative complications except in one patient who developed deep vein thrombosis in the left calf; this was successfully treated with anticoagulant therapy.
Due to favorable results and low incidence of perioperative complications and in the absence of other associated abdominal pathology, we propose the midline transperitoneal approach with mobilization or temporary resection of LIVC.
Background and Objectives: It has been suggested that intense feelings of fear/anxiety and significant patient concerns may affect the perioperative course. Those findings emphasize the importance of ...surgical patients’ preoperative feelings. Still, current knowledge in this area is based on a limited number of studies. Thus, we think that there is a need to further explore patients’ preoperative fears, better characterize risk factors and reasons for their occurrence, and evaluate patients’ perspectives associated with anesthesia. Materials and Methods: A total of 385 patients undergoing vascular surgery were preoperatively interviewed using a questionnaire that included demographics and questions related to patients’ fears and perceptions of anesthesia. Statistical analyses included descriptive statistics, Pearson’s χ2 and McNemar tests, and multivariate ordinal logistic regression. Results: The main causes of patients’ preoperative fear were surgery (53.2%), potential complications (46.5%), and anesthesia (40%). Female sex was a predictor of surgery and anesthesia-related fear (OR = 3.07, p = 0.001; OR = 2.4, p = 0.001, respectively). Previous experience lowered the fear of current surgery (OR = 0.65, p = 0.031) and anesthesia (OR = 0.6, p = 0.017). Type of surgery, type of anesthesia, educational and socioeconomic status, and personal knowledge of an anesthesiologist affected specific anesthesia-related fears. Over 25% of patients did not know that an anesthesiologist is a physician, and only 17.7% knew where anesthesiologists work. Level of education and place of residence influenced patients’ perceptions of anesthesia. Conclusions: Anesthesia-related fears are affected by the type of surgery/anesthesia, experience with previous surgery, and personal knowledge of an anesthesiologist. Women, patients with lower education levels, and patients with poorer socioeconomic status are at higher risk of developing those fears. The perception of anesthesiologists is inadequate, and knowledge of anesthesia is poor. Promotion of patient education regarding anesthesia is needed to alleviate those fears and increase understanding of anesthesia.
Perspective of using biogas in Serbia in European context Cvetkovic, Slobodan M.; Radoičić, Tatjana Kaludjerović; Kijevcanin, Mirjana
Energy sources. Part B, Economics, planning and policy,
01/2017, Letnik:
12, Številka:
4
Journal Article
Recenzirano
The aim of this study is to analyze the possibility of achieving the goal related to share of biogas energy in the final energy consumption in Republic of Serbia up to 2030 which refers to reach of ...2% of electricity produced from biogas, 1% of the final energy consumption in transport produced from biogas, and 1% of the final heat energy consumption from biogas in accordance with the recommendations of the European Biomass Association (AEBIOM). The analysis was performed on the basis of estimated biogas potential, where biogas was produced from energy crops dedicated to energy production, animal husbandry, municipal solid waste, waste from the meat industry and dairy industry wastewater as well as Serbian energy development strategy until 2030.
Background
One of the rare forms of abdominal aortic aneurysm (AAA) rupture is the rupture into great abdominal veins such as the inferior vein cava (IVC), the iliac veins, or the left renal vein, ...with the formation of direct or indirect aorto-caval fistula (ACF). The purpose of the present study was to summarize 20 years of experience at a single referral center for vascular surgery in a developing country, and to discuss the clinical presentation, diagnosis, treatment options, and outcome of patients with spontaneous aorto-venous fistulas (AVF) caused by ruptured aortic aneurysms.
Materials and methods
Retrospective database review identified 50 patients treated in our institution for aorto-venous fistulas (AVF) caused by spontaneous AAA rupture in the 20 years 1991–2010. Pulsating abdominal mass and low back pain were the leading symptoms on admission in our patients. Signs of shock, congestive heart failure, or pelvic and lower extremity venous hypertension were present in 48%, 26%, and 75% of the patients, respectively. Diagnosis of AVF was based on physical examination, duplex ultrasonography, conventional angiography, or multislice computed tomography (MSCT). In 40% of the patients the presence of AVF has not been recognized before surgery. All patients were treated with open surgery.
Results
After proximal and distal bleeding control the fistula was closed with direct suture (92%) or patch angioplasty (8%). Aortic reconstruction followed with tubular (22%) or bifurcated (78%) synthetic graft. Six (12%) patients died. The causes of death were excessive intraoperative blood loss, myocardial infarction, left colon gangrene and multiple organ failure.
Conclusions
Spontaneous AVFs caused by aneurysmal rupture are not uncommon, and they require prompt surgical or endovascular treatment. Routine use of multislice CT in patients with acute aortic syndrome is probably the best way to the correct diagnosis of aorto-venous fistulas and planning of the optimal treatment.
