Tag Archives: optimization

xxx D.A. Balogun, M.A. Oke, L. Rocha-Meneses, O B. Fawole and P.F. Omojasola
Phosphate solubilization potential of indigenous rhizosphere fungi and their biofertilizer formulations
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Phosphate solubilization potential of indigenous rhizosphere fungi and their biofertilizer formulations

D.A. Balogun¹², M.A. Oke³, L. Rocha-Meneses⁴⁵, O B. Fawole⁶ and P.F. Omojasola¹*

¹Department of Microbiology, Faculty of Life Sciences, University of Ilorin, 1515 Ilorin, Nigeria
²Nigerian Stored Products Research Institute, 1489 Ibadan, Nigeria
³Independent Researcher, Edmonton, AB, Canada. T5X 0H2.
⁴Biomass & Bioenergy Research Group, Center for Sustainable Energy and Power Systems Research, Research Institute of Sciences and Engineering, University of Sharjah, 27272 Sharjah, United Arab Emirates
⁵Institute of Technology, Chair of Biosystems Engineering, Estonian University of Life Sciences, Kreutzwaldi 56, 51006 Tartu, Estonia
⁶Department of Agronomy, Faculty of Agriculture, University of Ilorin, 1515 Ilorin, Nigeria
*Correspondence: jasola@unilorin.edu.ng

Abstract:

The harmful effects of chemical fertilizers on soil, plants, and eco-systems have stimulated the growth of the global biofertilizer market. However, biofertilizer use remains limited in developing countries due to inadequate research and poor technology. The use of readily available materials for biofertilizer production can be a good starting point. This study aimed to investigate phosphate-solubilizing potentials of soil fungi and the shelf-life of their biofertilizer formulations using sawdust and charcoal as carriers. Soil samples from the rhizosphere were cultured on Pikovskaya (PVK) agar, and the best phosphate solubilizers (Aspergillus niger, Aspergillus fumigatus and A. flavus) were screened for their phosphate-solubilization potentials on solid medium. Results obtained showed that A. niger had the highest solubilization index of 1.72, followed by A. fumigatus, and A. flavus with a solubilization index of 1.01 and 0.95, respectively. Optimization studies showed that after 5 days of incubation, A. niger, A. flavus and A. fumigatus solubilized 149, 112 and 126 mg L-1 of phosphate, respectively. These values increased to 549 mg L-1 on day 11 for A. niger, 379 mg L-1 on day 9 for A. flavus and 430 mg L-1 on day 9 for A. fumigatus. Furthermore, A. fumigatus and A. flavus proved to be better inoculants than A. niger as they maintained higher CFU g-1 counts throughout the experiment. Also, sawdust supported higher counts of the three inoculants than charcoal and was thus the best carrier. The findings demonstrated that these aspergilli can be harnessed for improving soil fertility and plant development.

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1498–1515 L.A. Souza, F.C. Silva, A.C.L. Maria, A.L. Belem, D. Cecchin and M.M. Barros
Response surface for biodiesel production from soybean oil by ethylic route
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Response surface for biodiesel production from soybean oil by ethylic route

L.A. Souza¹, F.C. Silva¹*, A.C.L. Maria¹, A.L. Belem¹, D. Cecchin¹ and M.M. Barros²

¹Federal Fluminense University, Agricultural and Environmental Engineering Department, 156 Rua Passos da Pátria 156, bloco D, sala 235, 24210-240, Niterói, Brasil
²Federal Rural University of Rio de Janeiro, Engineering Department, Rodovia BR 465, Km 07, s/n Zona Rural, 23890-000, Seropédica, Brasil
*Correspondence: flaviocastro@id.uff.br

Abstract:

Petroleum has been the most consumed energy source in the world, but it tends to run out due its non-renewable character. Among biofuels, biodiesel has emerged as the main candidate to substitute petroleum diesel. The present study aimed to identify the maximum yield point of biodiesel production by generating a response surface using molar ratio, temperature and agitation time as independent variables, and yield as a dependent variable. From the response surface, it is observed that the increase in temperature and reaction time leads to reduced yield. The configuration that resulted in maximum yield of 93.30% was 12:1 molar ratio, 30 °C temperature and 30-minute reaction time. From the chromatographic analysis it was possible to identify five different fatty acids in the composition of the biodiesels. Total saturated fatty acids (palmitic and stearic acids) ranged from 41.53% to 42.09% and total unsaturated fatty acids including monounsaturated and polyunsaturated fatty acids (oleic, linoleic and linolenic acids) ranged from 57.92% to 58.48%. According to the results of the physicochemical analyses, the specific mass at 68 °F is in agreement with Brazilian, American and European specifications, ranging from 877.46 kg m-3 to 879.64 kg m-3. The kinematic viscosity at 104 °F ranged from 4.49 mm² s-1 to 4.82 mm² s-1. The acid value obtained did not vary within the limits established by the norms, and values between 0.54 and 2.74 mg KOH g-1 were observed.

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958–968 H. Pihlap, A. Annuk, M. Lehtonen, S. Muiste, A. Tooming and A. Allik
A control method for increasing the heat usage efficiency of nearly-zero-energy buildings with heat pumps
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A control method for increasing the heat usage efficiency of nearly-zero-energy buildings with heat pumps

H. Pihlap¹*, A. Annuk¹, M. Lehtonen², S. Muiste¹, A. Tooming¹ and A. Allik¹

¹Estonian University of Life Sciences, Institute of Technology, Chair of Energy Application Engineering, Kreutzwaldi 56, EE51006 Tartu, Estonia
²Aalto University, Department of Electrical Engineering and Automation, Maarintie 8, Espoo, Finland
*Correspondence: heino.pihlap@emu.ee

Abstract:

In the retrofitting of older buildings with central heating into nearly zero-energy buildings more and more air to water heat pumps are used. These heat pumps are normally connected to heating systems, producing heat only on demand. The greatest demand for heat occurs when the outside temperature and therefore the COP of the pump is lowest. Outside temperature varies during the day, meaning it is possible to save energy by producing and storing heat in a situation where the COP is higher. To determine the periods with higher COP values weather forecast data and COP curves are used. The data enables to rank and select time periods for heat production. This in conjunction with the heat demand curve of the building enables to create an operation schedule for the heat pump. The aim of the study is to develop heat pump control methods for renovated buildings to comply with nearly zero energy building codes. Dependent on the heat pump and weather conditions, up to 10 % of the electricity demand for heating can be decreased.

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2127-2138 O. Zinina, S. Merenkova, M. Rebezov, D. Tazeddinova, Z. Yessimbekov and V. Vietoris
Optimization of cattle by-products amino acid composition formula
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Optimization of cattle by-products amino acid composition formula

O. Zinina¹*, S. Merenkova¹, M. Rebezov², D. Tazeddinova¹, Z. Yessimbekov³ and V. Vietoris⁴

¹South Ural State University (National Research University), Lenin Avenue 76, RU454080 Chelyabinsk, Russia
²Ural State Agrarian University, Karl Liebknecht 42, RU620075 Ekaterinburg, Russia
³Shakarim State University of Semey, Glinki street 20a, KZ071400 Semey, Kazakhstan
⁴Slovak University of Agriculture in Nitra, Hlinku 2, SK94901 Nitra, Slovakia
*Correspondence: zininaov@susu.ru

Abstract:

The aim of this research was to develop optimal formulations of by-product mixtures in terms of biological value using MS Excel Solver standard software application. The objects of study were underutilized cattle by-products as tripe, ears, lips, lungs, and heart. Physical and chemical studies were carried out to compile a database of the by-products used. As a result, the protein content was 14.3% in tripe, 24.6% in lips, 24.9% in ears, 15.2% in lungs, and 16.8% in heart (P < 0.05). The content of essential amino acids in various by-products, determined by high-performance liquid chromatography, did not have significant differences compared with the results obtained by other researchers. While conducting optimization of the by-product formulation, focused on the physiologically-based content of the essential amino acids in the ‛ideal’ protein according to the Food and Agriculture Organization of the United Nations and the World Health Organization (FAO/WHO). Essential amino acids index (EAAI) was chosen as the goal function. In the process of optimization, indicators such as chemical score, EAAI, biological value, and coefficient of amino acid score differences (CAASD) were calculated. Several variants of the formulations with high biological value were obtained as a result of the optimization. According to the results of the research it was found that more balanced ratio of the essential amino acids was in the following formulations: 1 – tripe (4.9%), ears (28.4%) and heart (66.7%) or 2 – ears (25.4%), lips (8.9%) and heart (65.7%). According to the results, the highest in vitro protein digestibility was in compositions number 1 and 2 (78.2% and 76.8%), which correlated with the calculated biological value. Thus, the use of computer modeling allowed obtaining the formulations of the by-products composition with the highest possible biological value by varying the content of the various by-products.

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1752-1761 M. Kroulik, J. Hula and V. Brant
Field trajectories proposals as a tool for increasing work efficiency and sustainable land management
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Field trajectories proposals as a tool for increasing work efficiency and sustainable land management

M. Kroulik¹*, J. Hula¹ and V. Brant²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Agricultural Machines, Kamycka 129, CZ16500 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Agroecology and Biometeorology, Kamycka 129, CZ16500 Prague, Czech Republic
*Correspondence: kroulik@tf.czu.cz

Abstract:

Together with the requirement for higher productivity the average performance and the weight of agricultural machines are increasing. Agricultural land is increasingly exposed to pressures caused by agricultural machinery. The heavy agricultural machinery passes across a field are frequently associated with technogenic soil compaction. Soil compaction is one of the main problems of modern agriculture. From the previous measuring of the traffic intensity it was found 86.13% of the total field area was run-over with a machine at least once a year, when using conventional tillage and 63.75% of the total field area was run-over when using direct seeding technology, with dependence on the working width of the machines. Field passes are inevitable in present agriculture. As a result of the increase of total machines weight, it is necessary to optimize the traffic lines trajectories and limit the entries of the machines in the field. At present, the choice of traffic lines direction is based primarily on the experience of drivers or the practice of farmers. There are a number of influences that affect the machine work efficiency. Monitoring of the tractor, on an irregular 8 fields showed the following results. Eight-meter working width tiller or seeder brought shortening of total length of turns at headlands with the change in trajectory azimuth. For purposes of measuring the monitored tractors were equipped with monitoring units ITineris. An overview of the chosen directions of the trajectories and the lengths of working and non-working passes was obtained. Based on the shape of the plot, the trajectory of the lines was also modelled. Suitable traffic lines directions in terms of the ratio of work and non-work passes were searched.
Based on records of real trajectories, the ratio of working and non-working path ranged between 6.3 and 15.2%. It was obvious from the results that the shortening of non-working passes and turns in comparison with the originally chosen trajectory directions was achieved by optimization. This was especially valid for complex shapes of fields. Trajectory optimization leads to a reduction of total length of path in all cases. The reduction in total length of path ranged from 69.7 m to 1,004.8 m. Changing the length of the working path ranged from 10.9 m to 264.9 m with the change in azimuth. The extension was observed in three cases. The highest part on the change of the overall length of the path presented nonworking rides.

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969-978 L. Klavina
A study on bryophyte chemical composition–search for new applications
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A study on bryophyte chemical composition–search for new applications

L. Klavina

University of Latvia, Department of Environmental Science, Raina Blvd. 19, Riga, LV-1586, Latvia; e-mail: laura.klavina@lu.lv

Abstract:

Bryophytes are the taxonomic group in the plant kingdom represented with about 25’000 species. They contain a high number of biologically active compounds; however their use as a food source is negligible. The aim of this paper is to evaluate bryophyte chemical composition and new possible applications. In order to evaluate bryophyte potential usage as a raw food material, bryophyte basic chemical content and the secondary metabolite profile was determined. To obtain best results bryophyte secondary metabolite extraction options has been studied. Couple of extraction methods were used (conventional, ultrasound, microwave, supercritical CO2 extraction etc.) and different solvents (ethanol, water etc.). A total concentration of polyphenols and substances determining free radical scavenging activity has been determined. The extracts obtained from bryophytes have remarkable antioxidant activity, the extent of which depends on the extraction conditions and bryophyte species. Comparison of five extraction methods and several solvents indicates that microwave assisted extraction and supercritical CO2 extraction is the most promising approach to obtain highest yields of extractives.

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