Andmebaasi logo

2018, Vol. 16, No. 4

Selle kollektsiooni püsiv URI


Viimati lisatud

Nüüd näidatakse 1 - 20 33
  • Kirje
    Morphological and biochemical indicators of Fusarium oxysporum f sp. fragariae in strawberry crops (Fragaria x ananassa Duch) in the province of Pichincha, Ecuador
    (2018) Salazar, S.; Bayas-Morejón, F.; Niño, Z.; Guevara, J.; Ruilova, M.; Merino, O.; Donato, W.; Guamán, J.
    Fusarium oxysporum f. sp. fragariae is a fungal pathogen, transmitted by soil in crops of strawberry (Fragaria x ananassa Duch.), which causes wilt disease that, kill the strawberry cultivars. The disease caused by Fusarium oxysporum f. sp., fragariae is hard to detect as the of the symptoms are similar with other soil-borne diseases. In spite of detection methods targeted F. oxysporum using molecular criteria have been developed, they have not been shown to successfully identity the unique identity of F. oxysporum strain that causes this disease. In Ecuador, the cultivation of strawberry has acquired great importance for the consumption, promoting the increase of its production. However, the process of importing plant material from producing countries for the purpose of improving production has contributed to the spread of the fungus. The objective of this study was to identify the presence of the Fusarium oxysporum f. sp fragariae by means of morphometric identification and the application of biochemical methods (BIOLOG) in the province of Pichincha. Fifty-two diseased strawberry plants and 52 asymptomatic plants were analyzed. Of these, 13 isolates were identified by morphometry as F. oxysporum. However, through BIOLOG four strains were identified as F. oxysporum, 5 as Fusarium sp., 2 F. lateritium, 1 F. udum and 1 strain as F. sacchari. The results obtained through the identification and evaluation confirmed the presence of F. oxysporum f. sp., fragariae in evaluated strawberry cultivars, thus determining the high risk to exist if the pathogen spreads in new plantations in Ecuador.
  • Kirje
    Effect of environmental temperature on bending strength of the finger jointed aspen lumber
    (2018) Iejavs, J.; Spulle, U.; Jakovlevs, V.; Buksans, E.; Zelmenis, A.
    Glued sauna wall boards are used as non-load-bearing structures. These products are subject to aggressive microclimate impact and very often for the gluing in length and width thermoplastic polyvinyl acetate adhesives (PVAC) are used. In the performed research sauna wall boards made of common aspen (Populus tremula L.) with mean wood moisture content 8% were used. For the gluing in length with finger joint PVAC glue of D4 (LVS EN 204) group was used. The aim of the research is identifying the impact of the environmental temperature on the strength of finger jointed aspen timber in 4 point static bending (in compliance with standard LVS EN 408). As a result of the study it was established, that after holding the finger jointed testing pieces visible in flat wise for 3 hours at the temperature of 100°C , the mean bending strength decreased by 56% or 31.7 MPa in comparison to that held in the standard atmosphere. In case of the aspen timber with finger joints visible in edge wise held for 3 hours at the temperature of 100°C , the bending strength decreased by 60% or 29.3 MPa in comparison to the testing pieces of the same type held in the standard atmosphere.
  • Kirje
    Agronomic evaluation of a Colombian passion fruit (Passiflora edulis Sims) germplasm collection
    (2018) Galeano Mendoza, C.H.; Cerón-Souza, I.; Arango, L.V.
    Passion fruit (Passiflora edulis Sims) is one of the most promissory crops in Colombia with approximately 7,400 ha cultivated, an average production of 89,000 t and an average yield of 15 t ha-1. However, low yields as well as harvest problems including fruit quality, generate important losses, mainly due to lack of improved cultivars with particular characteristics for each market (fresh consumption, agroindustry) and specific adaptations to biotic and abiotic stress factors in producer areas. Therefore, as a pre-breeding phase, this study aimed at characterizing preliminary the production and physiochemical characteristics of 60 passion fruit germplasm accessions maintained in Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA). We cultivated these accessions in the field for 22 months between 2014 and 2015, measuring 17 variables associated to both yield production and fruit quality. We analysed data using phenetic and multivariate methods to establish levels of genetic diversity. Additionally, we constructed a selection index (SI) with the most informative variables to select individuals according to fruit weight, shape and colour, as well as juice percentage. Results of genetic grouping and principal components showed a broad genetic diversity across the working collection, without any population substructure. Fruit volume, pulp and seed weight were the variables that explained 80% of the phenotypic variation. Finally, we identified 30 promissory accessions as parental for the first cycle of recurrent selection using the SI. We conclude that this core collection represents the diversity included in the working collection with promissory accessions to initiate an intra-population recurrent selection program.
  • Kirje
    Evaluation of greenhouse gas emissions and area of organic soils in cropland and grassland in Latvia – integrated National forest inventory data and soil maps approach
    (2018) Petaja, G.; Okmanis, M.; Polmanis, K.; Stola, J.; Spalva, G.; Jansons, J.
    The aim of the research was to assess distribution of organic soils in farmlands for the time period between 1990 and 2015, as well as to carry out a recalculation of GHG emissions from organic soils in grassland and cropland. We evaluated the area of typical organic soils using digitized soil maps created between 1960s and 1980s there were 183,000 ha of cropland and grassland on organic soils. A selected number of areas on organic soils intersecting with the National forest inventory (NFI) plots were surveyed. We found that 66 ± 10% of surveyed plots still conforms to criteria for organic soils according to Intergovernmental Panel on Climate Change (IPCC) guidelines; in the rest of plots soil organic matter has been mineralized and these areas do not conform to IPCC criteria of organic soils. The following distributionof organic soils was estimated in cropland – 6.3 ± 3.3% in 1990 and 4.1 ± 3.4% in 2015, but in grassland – 11.6 ± 3.6% in 1990 and 7.7 ± 3.9% in 2015. The annual reduction of GHG emissions due to reduction of area of organic soils in cropland in 2015 corresponds to 1,400,000 tonnes CO2 eq. in comparison to 1990 and in grassland – to 1,100,000 tonnes CO2 eq. The estimated reduction of the GHG emissions due to conversion of organic soils into mineral soils, comparing the average value in 2005–2009 with the projection for 2021–2030 on average will correspond to 313,000 tonnes CO2 eq. annually, however LULUCF sector still won’t become a net CO2 sink according to the GHG inventory data on other land use categories and carbon pools.
  • Kirje
    Farm manure amount calculation using statistical data in Latvia
    (2018) Priekulis, J.; Aboltins, A.; Laurs, A.; Melece, L.
    To calculate ammonia emissions caused by production, storage and application of farm manure, it is necessary to know the amount of farm manure obtained in the country and also the kinds of manure. For this purpose, methodology and computer software are dev eloped to calculate the amount of farm manure based on the data of the Central Statistical Bureau, the technology of farm animal handling in the country and the respective valid normative documents. Upon calculating the amount of farm manure produced in La tvia in 2016, it was stated that approximately a half of the manure is litter manure, one third – liquid manure, and one fifth – manure left in the pastures. The most of manure in Latvia (69% of the total amount) is obtained from milk cows, their calves an d young stock.
  • Kirje
    Assessment of potato plant development from Minitubers
    (2018) Dimante, I.; Gaile, Z.
    In production of minitubers, mani pulation of their weight by modifying production method is common. Under field conditions plant development from minitubers can be affected by their weight, as well as cultivar. This objective of this study was to compare plant development from four minitu ber weight classes (MtC) (3 to 4.99 g, 5 to 9.99 g, 10 to 19.99 g, and > 20 g) with broken apical dominance of cultivars ‘Monta’, ‘Prelma’ and ‘Mandaga’. ‘Prelma’ and ‘Mandaga’ had a similar development pattern, and minitubers > 20 g required significantly less growing degree days (GDD) to emerge than minitubers from the lightest classes. The heaviest minitubers needed on average 176 GDD for 50% emergence and 207 GDD were needed for the lightest class. The difference in GDD between the marginal MtC was more pronounced in period between 50 and 80% emergence. MtC did not affect the final rate of emergence. Number of above ground stems (1.4 – 4.0) was significantly affected by MtC. ‘Monta’ had significantly different development – delayed emergence, lower emergen ce rate, less above ground stems, faster canopy closure. Our study showed that plant development was significantly affected by MtC and cultivar. Differences between MtC were more pronounced under adverse meteorological condi tions.
  • Kirje
    The impact of weather conditions on microclimate in storage facilities
    (2018) Bradna, J.; Šimon, J.; Hájek, D.; Vejchar, D.
    The key to maintaining good qualitative parameters of stored grain on farms is to achieve and maintain suitable storage temperatures relative to the outside temperature. In the framework of this research, the main focus was on typical representatives of grain storage facilities used in the Czech agriculture. In the post - harvest period after the crops were stored in the chosen storage facilities, the temperature of the material was monitored at 15 - minute intervals using an external temperature probe as well as the temperature and dew point of the outdoor air. A simple linear regression model was used for data analysis. The correlated temperature d ependence of the stored grain varies considerably in the monitored storage facilities. The storage halls were characterized by a low dependence (r = 0.2208) of the temperature of the material on the outside air temperature in the first 4 months following t he harvest when the grains were being stabilized by active aeration. In addition to the grain and the air temperature, the second focus was monitoring the dew point, i.e. assessing the risk of water vapour condensation on the surface in the upper layer of the stored grain, which is very undesirable for maintaining the quality of the stored grain. The results show that the monitored storage hall can be characterized by the ability to maintain the required climate due to outdoor climatic conditions. In genera l, this ability mainly depends on the type and design of the storage facility, the aeration system and also the storage capacity. Mainly during spring the dew point and water vapour condensation can often happen within the grain, therefore the need to focu s on appropriate measures such as reduced aeration or increased grain mixing, and thus avoiding the formation of critical spots.
  • Kirje
    POST herbicide programme for effective weed control in winter wheat (Triticum aestivum L.)
    (2018) Pacanoski, Z.; Mehmeti, A.
    Field experiments were conducted during two winter wheat - growing seasons to evaluate the efficacy of some new POST herbicides and herbicide combinations for those effective controls of weeds in winter wheat crops in the Republic of Macedonia. The weed population consisted mainly of annua l winter and spring and some perennial weeds. Weediness comprised 116 and 208 plants m - 2 in 2012 – 2013 and 2013 – 2014, respectively, in the Skopje region, and 93 and 114 plants m - 2 in 2012 – 2013 and 2013 – 2014, respectively, in the Probištip region. All POST h erbicides effectively reduced dominant weeds density ( > 93%) in the Skopje region in both years, as well as in the Probištip region in 2012 – 2013, but not in 2013 – 2014. In this year, lower temperature directly following application decreased efficacy of POS T applied herbicides, which provided control of Lolium perenne that was between 76 and 84%; control of A. ludoviciana was less than 85%; control of B. radians was no more than 83% and no one treatment controlled P. convolvulus more than 82%. Wheat yields i n the Skopje region were not significant among years for the different POST herbicide applications and ranged between 3,580 and 3,720 kg ha - 1 in 2012 – 2013, and between 3,760 and 3,910 kg ha - 1 in 2013 – 2014. A significant treatment by year interaction resulted in two distinct years for wheat yields in the Probištip region with POST herbicides. In 2012 – 2013, wheat yields were between 3,230 and 3,390 kg ha - 1 , but in 2013 – 2014, wheat yields ranged from 3,060 to 3,4 90 kg ha - 1 and weed - free control showed a significant higher wheat yield compared to all evaluated herbicides.
  • Kirje
    Mathematical model of cleaning potatoes on surface of spiral separator
    (2018) Bulgakov, V.; Nikolaenko, S.; Arak, Margus; Holovach, I.; Ruzhуlo, Z.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    Cleaning potato tubers from soil impurities and plant debris after digging them out of soil is a topical problem in the work process of potato production. Therefore, the engineer ing of new designs of potato heap separators necessitates the further studying of them and the optimisation of their kinematic and design parameters, which must not only ensure the high quality of cleaning, but also rule out the possibility of damaging the tubers. The aim of this study is to determine the design and kinematic parameters of the improved design of the spiral potato separator, which will ensure the high quality of cleaning and rule out the possibility of damaging the tubers, on the basis of th e development of the new theory of potato tuber’s motion on the surface of the separator. An analytical study has been carried out resulting in the construction of the equivalent schematic model of the interaction between the potato tuber and separator, th e tuber being approximated by a material point on the surface formed by the two cantilevered spirals, which are the separator’s tools. The separator’s spirals are driven to rotate and at the same time they can perform oscillations in the vertical and axial plane under the action of the varying load generated by the continuous feeding of the potato heap for separation. In the model, the forces acting on the potato tuber’s body are applied to it, the coordinate axes that have been selected and appropriately o riented are shown. A system of equations has been set up for the constructed equivalent schematic model, comprising three differential equations of the potato tuber body’s motion on the surface of the trough formed by the two cantilevered spirals. The dete rmined kinematic and design parameters will allow to raise the quality of cleaning potato tubers from soil impurities and plant debris. .
  • Kirje
    Suitability of Common nettle (Urticadioica) and Canadian goldenrod (Solidagocanadensis) for methane production
    (2018) Dubrovskis, V.; Plume, I.; Straume, I.
    Support for biogas production in Latvia was decreased. There is an urgent need to i nvestigate the suitability of various inexpensive renewable biomass resources for energy production. Also, itis necessary to explore the possibilities to improve the anaerobic fermentation process with the help of various catalysts. Biocatalyst Metaferm pr oduced in Latvia was used in previous studies with other biomass and showed increase in biogas and methane production. The article shows the results of studies on biogas (methane) production from chopped fresh Common nettle ( Urtica dioica ) and Canadian gol denrod ( Solidago canadensis ) biomass and effect of catalyst Metaferm in anaerobic fermentation process. The anaerobic digestion process was performed in 0.75 L laboratory digesters, operated in batch mode (38 ± 1.0 °C, 35 days). The average specific biogas or methane production per unit of dry organic matter added (DOM) from Common nettle was 0.709 L g - 1 DOM or was 0.324 L g - 1 DOM respectively. Average specific biogas or methane volume produced from chopped Canadian goldenrod in anaerobic fermentation was 0.54 8 L g - 1 DOM or 0.267 L g - 1 DOM respectively. Average biogas or methane yield from digestion of chopped Common nettle with 1 mL Metaferm was 0.752 L g - 1 DOM or 0.328 L g - 1 DOM respectively. Average specific biogas or methane yield from anaerobic fermentation of c hopped Canadian goldenrod with 1 mL Metaferm was 0.624 L g - 1 DOM or 0.276 L g - 1 DOM respectively. Adding of catalyst Metaferm increases methane yield from chopped nettle or Canadian goldenrod by 1.2% or 3.4% respectively. All investigated biomass resources c an be used for methane production.
  • Kirje
    Assessment of the actual hand position on the steering wheel for drivers of passenger cars while driving
    (2018) Hruška, M.
    This work deals with the assessment of the actual position of the hands on the steering wheel of drivers of passenger cars in specific driving modes. The findings are compared with the location that is generally considered to be optimal in terms of both active and passive safety, and the long - term effects on the health of the driver. The research desc ribed in this work was carried out on a sample of randomly selected drivers in the Czech Republic. For all of the measurements, one identical neutral passenger middle - class vehicle, with which none of the test subjects had previous experience, was selected . The reason for this research was to model a normal situation where the driver controls a vehicle with his hands on the steering wheel in a position that is only the result of his or her own intuition and the subjective sense of the driver’s comfort. On t he basis, of a statistical evaluation of the obtained data, it was found that the introductory hypothesis, which states that a significant part of the tested sample of drivers holds the steering wheel in an unsuitable manner, can be confirmed. This fact ne gatively impacts not only on the reduction of active and passive safety, but also affects the health of drivers who drive a large amount of kilometres annually. The results of this work can be used in the design of cabs and modern passenger car systems tha t will be able to motivate the driver to hold the steering wheel in an optimal way. This will directly affect road safety and positively influence the health of drivers.
  • Kirje
    Faults and the physical workload in sawing and packing-related woodworking processes when considering potential ergonomic solutions
    (2018) Kalkis, H.; Roja, Z.; Babris, S.
    The forest sector is a high - risk economic sector in Latvia, one in which manual work, awkward postures, the tightening up of individual muscle groups, and work monotony still exists. The aim of this study was to analyse the physical workload and fault modes, and their effects on the sawing and packing proce sses in woodworking when considering potential ergonomic solutions. Results show that packing operators and saw operators alike are exposed to severe loads, and these results coincide with survey results in which employees in these professions complain abo ut the physical load and mention lower back pain. Fault modes and their effects on the sawing and packing processes were analysed using Failure Mode and Effects Analysis, and the main errors which were revealed in packing operations were related to machine ry and lifting equipment, as well as to ergonomics and errors involving the human factor. The risk priority was calculated in terms of a figure. Financial indices were compared before and after any potential improvement in the sawing and packing processes. Analysis proves that investments in the improvement of ergonomics in relation to the automation of the production process saves human resources and is economically favourable when it comes to ensuring the sustainable development of the business in questio n.
  • Kirje
    Ergonomic modelling parameters and the influence of ergonomics on planning workplaces
    (2018) Maksimov, D.G.; Kalkis, H.
    Modern economic research divides all economics into structural levels: mega - economics, macroeconomics, meso - economics, micro - economics, and nano - economics. From the point of such traditional divisions, the research is topical in the primary economic struct ure of society – nano - economics – and thanks to this work operations can be subdivided into workplaces in the form of transformation processes. The aim of the research is to develop ergonomic modelling parameters and to discover the influence of ergonomics on the planning of workplaces ba sed on a case study. The research involved a study of workplace ergonomic planning methods and principles. Solutions for a series of problems which are related to the improvement of workplace ergonomics may be discovered in the following ways: improving wo rk organisation in every workplace by using work process - related micro - elemental methods and a determination of work expenditure, the levels of physical strenuousness involved in the work, the complexity of the work, and the social importance of the workpl ace. These parameters will allow the workplace quantity characteristics to be discovered, such as in terms of a generalised parameter which conforms to the requirements which describe a workplace, and in terms of operational management via the condition of workplaces and the salary systems being utilised. The research provides a case study in which ergonomic modelling parameters are developed and concrete workplace interventions are introduced.
  • Kirje
    Efficiency of the use of field beans in fattening lambs
    (2018) Kairisa, D.; Aplocina, E.
    The breeding and feeding of self produced pulses to livestock is one of the important directions of research for reducing the production costs of livestock products. Experiment on the effective using of the field beans to lambs for fattening was arranged in three replications using the Latvian Da rk - headed breed male lambs. The mixture of concentrated feed consisted of 50% of bean and 50% of oat. Lambs were weighed at the starting and ending of the trial. Carcass quality was assessed according to the European standard for the classification of carc asses of sheep. The fattening period lasted from 37 to 94 days, on average 63 ± 3.6 days. The average live weight gain per day was 247.4 ± 13.85 g, and live weight increased on average by 15.3 ± 0.94 kg. Significantly higher ( P < 0.05) growth rate during fattening period reached lambs of 3rd group, where lambs started fattening above 27 kg of live weight, reaching a 276.8 ± 26.26 g daily live weight gain. The quality of the obtained carcasses was an average, and score for musculatu re was from R to O class, but the average score for fat deposition was from 3 to 4 points. The mixture of field beans and oats provided 19.3% of crude protein and 12.1 MJ of metabolizable energy per 1kg of dry matter, and its unlimited feeding provided med ium lamb's growth rate. The level of feed conversion was 7.56 kg of dry matter .
  • Kirje
    Study of effect of arbuscular mycorrhiza (Glomus intraradices) fungus on wheat under nickel stress
    (2018) Heydarian, A.; Tohidi Moghadam, H.R.; Donath, T.W.; Sohrabi, M.
    In many regions of the world soils are contaminated with heavy metals and therefore restricted in their use. For instance, the absorption of nickel (Ni) in the tissue of plants increase the plant’s metabolism and cause physiological disorders or even death. Arbuscular mycorrhizal fungi are known to enhance the tolerance of host plants to abiotic and biotic stress. Thus, we investigated the potential of the arbuscular m ycorrhizal fungi Glomus intraradices to mitigate deleterious effects of Ni in wheat. The experiment was conducted using four levels of Ni (0, 60, 120 and 180 mg per kg of soil) and two levels of mycorrhizal fungi application (with and without Glomus intrar adices ). Nickel stress significantly decreased seed number per spike, thousand - seed weight, seed yield per plant, concentration of chlorophyll a and b. At the same time, we found increased catalase (CAT) enzyme activity and dityrosine (DT) treatments. Mycorrhizal fungi application attenuated Ni effects, i.e. fungal presence increased seed number per spike, thousand - seed weight, chlorophyll a and b. Furthermore mycorrhizal fungi application reduce CAT enzyme activity and DT. In general, our results sugge st that mycorrhizal fungi application reduces harmful effects of Ni stress in wheat.
  • Kirje
    Assessment of Calotropis natural dye extracts on the efficiency of dye-sensitized solar cells
    (2018) Alami, A.H.; Aokal, K.; Zhang, D.; Tawalbeh, M.; Alhammadi, A.; Taieb, A.
    This work presents the construction and testing of solar cells sensitized with natural dyes extracted from plants indigenous to the desert. Calotropis plants are self - sufficient as they grow in very harsh environments, and yet are not consumed by humans or livestock due to their irritating agents to the skin and eyes. The energy generators of these plants are the leaves, which are crushed and processed to produce the dye solution. Also, the Calotropis leaves are covered in a white powder that is thought to aid in mitigating the heat by scattering incident radiation. This powder material is examined and added to the dye as it proved advantageous for the o verall cell efficiency, which reached 0.214% compared with 0.108% for cells with no powder. The produced cells are also compared with ones sensitized by spinach, another common natural sensitizer for dye - sensitized solar cells, and the performance proved t o be significantly better. The fact that Calotropis is a non - food plant is an added advantage to utilizing it as a dye source, along with its intrinsic heat resistance that allows it to survive the harsh desert conditions all year round.
  • Kirje
    Additional concentrates do not affect feeding times of cows, but social positions of cows do
    (2018) Soonberg, Maria; Kass, Marko; Kaart, Tanel; Leming, Ragnar; Arney, David R.; Estonian University of Life Sciences. Department of Animal Nutrition; Estonian University of Life Sciences. Department of Animal Breeding and Biotechnology
    In robotic milking dairy systems lack of control over intakes can be problematic for balancing the forage and concentrate portions of diets. This can lead to proble ms associated with high concentrate intakes and concomitant low forage intakes. To check this as a problem, the feeding behaviour of cows was observed: the number of daily visits to the feed barrier, the duration of these visits and actual feeding, of high and low yielding cows. The cows were robot - milked and fed a ration comprising, separately, concentrate feed from a robot and a feeder, and a grass/clover silage mix forage at the feed barrier. Individual variation in visiting times and times spent at the feed barrier were greater than the effect of level of production. There was no evidence that cows with higher milk yields are differentially motivated to feed from forage. But more dominant cows spent more time feeding than submissive cows.
  • Kirje
    The influence of drying method to the changes of bioactive compounds in lingonberry by-products
    (2018) Ozola, L.; Kampuse, S.
    The aim of this research was to evaluate the effect of different drying methods on industrially obtained lingonberry pulp juice by - products. For investigations, by - product was dried using hot air dryer (at temperatures 80 °C , 60 °C and 40 °C ), microwave - vacuum dryer and freeze - dryer. The freshly defrosted by - product was used as control. All samples were analysed on the basis of their moisture content, colourimetric attributes (CIE L*a*b* colour system), content of vitamin C (iodometric method), content of total carotenes (TC), total phenol content (TPC), total anthocyanin content (TA) and antiradical activity (DPPH, ABTS + ). The obtained data on content of vitamin C showed a 10% decrease between control and sample dried in hot air at 80 °C . Similar changes were noticed with total anthocyanin content, the lowest amount was also foun in this sample ( 306.72 ± 18.32 mg 100 g - 1 DW). Total carotenes content was higher in freeze - dried sample (5.61 ± 0.16 mg 100 g - 1 DW) which was very close to control sample. A significant loss of total phenol content was noticed after drying, up to 80%, similar ten dencies were noticed with changes of antiradical activity. After evaluating the obtained data, the use of hot air dryer at 80 °C temperature resulted in the lowest amount of vitamin C and anthocyanins in lingonberry by - products, which makes this method unsuitable for drying by - products of these berries. However, vacuum assisted microwave drying and freeze drying showed less damaging impact on dried material.
  • Kirje
    Extended use of Sphagnum peat as a biosorbent for Zn(II): repetiti ous sorption-desorption process
    (2018) Denisova, V.; Tihomirova, K.; Mezule, L.
    In this study, continuous biosorption - desorption cycles in a fixed - bed column were performed to evaluate the extended use of sphagnum peat as biosorbent material to remove Zn(II) ions from aqueous solutions. Biosorption - desorption studies revealed that the sphagnum peat as biosorbent could be regenerated using 0.1M HCl as eluting agent with more than 70% recovery in four successive biosorption - desorption cycles. The results showed that the sphagnum peat should be used as an alternative, effective and low - cost biosorbent for Zn(II) ions removal from polluted aqueous solution.
  • Kirje
    Biostability of cotton fibers with different natural colors and selection
    (2018) Kotomenkova, O.; Vinogradova, A.
    Biodamageability is one of the weak sides of the cotton - plant fiber. Economic loss from the cotton damage caused by microorganisms is significant. Toxic chemical compounds are used to preserve the cotton fiber. This has a negative impact on environment and cotton consumer s. The degree of the cotton biodamage depends on selection variety, types of cultivation, storage conditions and other factors. One of the directions in cotton planting is selection of the boll - stained cotton. It was established that naturally colored cott on of different varieties has high biostability. It allows to product hypoallergenic, eco - friendly textile and reduces impact on the environment. The purpose of the work is stability evaluation for microbiological damage of different cotton varieties inclu ding those naturally colored during long - term storage in different temperature and humidity conditions. The research lasted for 10 years. The species composition of the cotton microflora was determined, the impact of fiber on microorganisms and dynamics of samples biodamage was studied in the work. The results obtained show preservation of microflora viability on cotton fiber when storing it under normal conditions for a long - term period. With an increase in temperature and humidity necessary for microorgan isms’ growth, the fiber destruction processes are amplified. It was established that cotton damage degree depends on the regimes and terms of its storage as well as the color of the fiber. Nature - colored cotton is more resistant for microorganisms, some va rieties inhibit the growth of mold fungi.