Wyniki wyszukiwania - Biblioteka Nauki

1

Dynamic analysis of embedded chains in mooring line for fish cage system

100%

Hou H. M. , Dong G. H. , Xu T. J. , Zhao Y. P. , Bi C. W.

Polish Maritime Research

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2018

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tom nr 4

83--97

EN

Investigation of the embedded chains in soil starts to play an important role in understanding the structural performance of mooring system, when the embedded anchors will be employed to sustain large loads with the gradually growth of installation depth of offshore aquaculture farm. The aim of this study is to investigate the dynamic response of mooring line considering the influence of embedded chains in clay soil for net cage system. Lumped-mass method is used to establish the numerical model for evaluating the performance of mooring line with embedded chains. To validate the numerical model, comparisons of numerical results with the analytical formulas and the experimental data are conducted. A good agreement of the profile and the tension response is obtained. Then, the effect of embedded chains on the static and dynamic response of mooring line is evaluated, and the dynamic behavior of mooring system considering embedded chains for net cage system is investigated. The results indicate that the soil resistance on embedded chains should be included to predict the mooring line development and the load on the embedded anchors in the numerical simulations. An appropriate safety factor should be included if employing the simplified model Case C at the initial design phase. And the effect of embedded chains on the holding capacity of embedded anchors in single-point mooring system for single net cage cannot be negligible during the design and operation phases. Consequently, it is profound to take into account the interaction of embedded chains and soil for accurately predicting the reliability of mooring system for fish cage.

2

Soil mechanical resistance measurement by an unique multi-cone tips horizontal sensor

88%

Sharifi A. , Mohsenimanesh A.

International Agrophysics

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2012

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tom 26

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nr 1

EN

Amulti-tips horizontal sensor was developed and mounted horizontally on a tine face by shafts. The length of shafts was reduced from top to down the tine. The developed system was evaluated in the controlled soil bin laboratory conditions with clay loam soil and uniform soil moisture content. The experiment was designed with soil compaction at three levels of uniform and nonuniform soil compaction in completely randomized block design with four replications. Vertical standard penetrometer was also used to compare with horizontal sensor data at whole working depth of 0 to 400 mm. The results indicated that there is a correlation with R2 = 0.86 between soil cone penetrometer values and the horizontal soil mechanical resistance measurement system data. It can be concluded that the idea of reducing the length of the tips from top to down the tine face would give promising results.

3

The analysis of soil resistance during screw displacement pile installation

88%

Krasiński A.

Studia Geotechnica et Mechanica

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2014

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tom Vol. 36, nr 3

49--56

EN

The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

4

Estimation of Screw Displacement Pile-Bearing Capacity Based on Drilling Resistances

88%

Krasiński A.

Studia Geotechnica et Mechanica

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2023

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tom Vol. 45, nr s1

282--292

EN

This article presents an engineering, empirical method of estimating the bearing capacity and settlement characteristics Q-s of screw displacement piles and columns, based on soil resistance encountered during the drilling to form piles/columns in the ground. The method was developed on the basis of correlation analyses of the test results of 24 piles made during the "DPDT-Auger" research project (Krasiński et al., 2022a). In the proposed method, the load capacity of a screw displacement pile is estimated using two main parameters of auger screwing resistance: torque MT and the number of auger rotations per depth unit nR. The method applies to piles and columns made with a standard screw displacement pile (SDP) auger and with the proprietary, prototype DPDT (displacement pile drilling tool) aguer, patented in Poland (2020). Based on the estimated ultimate capacities of the pile shaft and base, an approximate method of predicting the pile settlement characteristics Q-s was also proposed, using the transfer function method. This article describes a correlation procedure of field test results together with their statistical analysis and presents a method of estimating the pile-bearing capacity based on correlation results. A calculation example is also provided. The conclusion looks at the useful practical applications that could be found for the proposed method.

5

Sensitivity of soil enzymes to excessive zinc concentrations

75%

Borowik A. , Wyszkowska J. , Kucharski J. , Bacmaga M. , Boros-Lajszner E. , Tomkiel M.

Journal of Elementology

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2014

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tom 19

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nr 3

EN

The sensitivity of soil enzymes to soil contamination with zinc was analyzed. A laboratory experiment was performed on sandy loam at pH 7.0, sampled from arable land at a depth of 0 to 20 cm. Soil samples were passed through a sieve with 2 mm mesh size and contaminated with the following zinc doses: 0, 300, 600, 1200 and 2400 mg Zn2+ kg-1 soil. Zinc was applied in the form of aqueous solution of ZnCl2. Soil was mixed thoroughly with zinc, and its moisture content was brought to 50% capillary water capacity. The samples were incubated at 25°C. Beakers with soil samples were weighed once a week to replenish evaporated water. The activity of soil enzymes: dehydrogenases, urease, acid phosphatase, alkaline phosphatase, catalase, arylsulfatase and b-glucosidase, was determined after 15, 30, 60 and 120 days of the experiment. The results were used to calculate soil resistance (RS), ED20 and ED50 values. The results of the study indicate that soil enzymes are characterized by varied sensitivity to excessive zinc concentrations, and that the RS index is a reliable measure of enzymatic responses to zinc pollution. The analyzed enzymes were classified in the following decreasing order in terms of their resistance to zinc: b-glucosidase> acid phosphatase > urease >arylsulfatase = alkaline phosphatase> catalase > dehydrogenases. Zinc continued to exert a negative effect on soil enzymes throughout the experiment (120 days). ED20 values for the analyzed enzymes in mg Zn2+ kg-1 DM soil were determined at: 103 for dehydrogenases, 184 for alkaline phosphatase, 233 for urease, 247 for arylsulfatase, 416 for acid phosphatase, 419 for catalase and 1373 for b-glucosidase.

PL

Celem badań było określenie wrażliwości enzymów na zanieczyszczenie gleby cynkiem. Doświadczenie przeprowadzono w warunkach laboratoryjnych na glinie piaszczystej o pH 7,0, pobranej z użytku rolnego z warstwy od 0 do 20 cm. Przed rozpoczęciem badań glebę przesiano przez sito o oczkach 2 mm i zanieczyszczono następującymi dawkami cynku: 0, 300, 600, 1200, 2400 mg Zn2+ kg-1 gleby. Cynk stosowano w postaci wodnego roztworu ZnCl2. Następnie po dokładnym wymieszaniu gleby jej wilgotność doprowadzono do 50% kapilarnej pojemności wodnej i poddano inkubacji w cieplarce w temp. 25°C. Jeden raz w tygodniu zlewki przeważano w celu uzupełnienia ewentualnych ubytków wody. Po 15, 30, 60 i 120 dniach inkubacji część zlewek likwidowano i oznaczono aktywność enzymów glebowych: dehydrogenaz, ureazy, fosfatazy kwaśnej, fosfatazy alkalicznej, katalazy, arylosulfatazy i b-glukozydazy. Na podstawie wyników obliczono indeks oporności enzymów (RS) oraz wskaźniki ED20 i ED50. Stwierdzono, że enzymy glebowe mają zróżnicowaną oporność na nadmiar cynku w glebie, a wskaźnik oporności RS jest dobrą miarą ich reakcji na zanieczyszczenie tym metalem. Pod względem zmniejszającej się oporności można je uszeregować następująco: b-glukozydaza> fosfataza kwaśna > ureaza >arylosulfataza = fosfataza kwaśna > katalaza > dehydrogenazy. Negatywne działanie cynku na enzymy glebowe utrzymywało się przez cały okres badań (120 dni).Wartość ED20 dla poszczególnych enzymów w mg Zn2+ kg-1s.m. gleby wynosiła: dehydrogenazy – 103, fosfataza alkaliczna – 184, ureaza – 233, arylosulfataza – 247, fosfataza kwaśna – 416, katalaza – 419, b-glukozydaza – 1373.

6

Simplified technique for the determination of soil aggregation in assessing the resistance of soils to erosion and deflation

63%

Grigoriev V. , Piechnik L. , Podsiadlowski S.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2008

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tom 39

EN

The technique provides for the determination of the size and percentage of aggregates of the coarse fraction on the surface of a friable soil followed by the determination of the aggregation index to be used in assessing spatial and temporal resistance of soil to erosion and defl ation. The uses of this technique make routine sampling and aggregate analysis after Savvinov unnecessary. Its some outcomes for soils of Poland are given.

PL

Podatność gleby na erozję wodną i wietrzną determinowana jest wieloma czynnikami. Za jeden z ważniejszych uważa się przy tym stan ilościowy i jakościowy struktury agregatowej wierzchniej warstwy gleby. Celem pracy jest zatem przedstawienie nowej, względnie prostej, metody określania zależności między stanem struktury agregatowej wierzchniej warstwy gleby a podatnością tej gleby na erozję i defl ację. Metodę tę oparto o analizę ilościową struktury agregatowej, wykonywaną techniką przesiewania na sucho przez dobrany zestaw sit, zgodnie z procedurą podaną wcześniej przez Savinowa. Założono przy tym, iż analiza struktury agregatowej odbywa się bezpośrednio w warunkach polowych, co pozwala na uniknięcie wpływu transportu próbek na uzyskiwane wyniki przesiewania. Wykonywanie analiz w warunkach polowych jest przy tym szczególnie ważne w przypadku gleb o względnie niskiej wytrzymałości mechanicznej struktury agregatowej, a więc w przypadku piasków gliniastych. Przedstawianą metodę zastosowano z powodzeniem w badaniach prowadzonych w Stacji Hodowli Roślin Wierzenica, położonej nieopodal Poznania.

7

Ocena poziomego oporu gleby z wykorzystaniem teorii procesów stochastycznych

63%

Bajla J. , Walczykova M. , Štrba M. , Benda I.

Inżynieria Rolnicza

|

2005

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tom R. 9, nr 10

13--21

PL

W doświadczeniach polowych z penetrometrem poziomu uzyskano przebiegi poziomego oporu gleby, do opracowania których zastosowano metody dynamiki statystycznej. Wyniki wykazały, że na mierzonych głębokościach widmo wydajność było względnie niskie co zostało również potwierdzone testach Fishera. Statystycznie istotnych jest kilka częstotliwości, których wartość wacha się w przedziale od 0, 177 do 1,117 Hz. Na głębokości pomiaru 0,15 n aż siedem częstotliwości o wartości 0,177- 0.588H z jest statystycznie istotnych najbardziej częstotliwości, 196 Hz Oceniane i omawiane przebiegi oporów penetracji raz ich widma częstotliwości mogą być wykorzystanej jako parametry wstępne metodach optymalizacji racjonalizacji obliczeń oporów roboczych maszyn i narzędzi oraz ulepszeń ich konstrukcji. Metoda pomiaru oporu penetracji poziomym penetrometrem może być wykorzystana do szybkiego określenia stanu gleby dla celów rolnictwa precyzyjnego oraz do prognozowania oporów roboczych narzędzi stosowanych w rolnictwie.

EN

ln the field experiment with horizontal penetrometer the courses of horizontal soil resistance were obtained and then evaluated by the help of statistical dynamics method. The results of analyses showed that at the measured depths the power of the spectrum was relatively low, which was confirmed by the Fisher's test. There were some significant frequencies. Their intensity fell into an interval 0.177, 1.177H z. At the, depth o f 0.15 m as many as seven frequencies, varying from 0.177H z to 0.588 Hz. were statistically significant, among them the frequency of 0.196 Hz in the highest degree. Evaluated and described courses of penetration resistance and their frequency spectra could be used as entrance parameters for rationalizing and optimizing the working resistance calculation of tools and machines as well as and for modification of their design. The method of penetration resistance measurement by horizontal penetrometecr could be used for quick determination f the soil conditions for the purpose of precision agriculture and for prediction of the working resistance of the equipment used in agriculture.

8

Problem interpretacji kąta tarcia wewnętrznego w badaniach trójosiowego ściskania gruntów niespoistych

63%

Parylak K.

Zeszyty Naukowe. Budownictwo / Politechnika Śląska

|

2003

|

tom z. 97

23-30

PL

W pracy dokonano przeglądu hipotez wytrzymałościowych i interpretacji kąta tarcia wewnętrznego gruntów dla krzywoliniowych obwiedni kół Mohra uzyskiwanych w badaniach trójosiowego ściskania. Przedstawiono metodę Maksimovica wyznaczania uśrednionej wartości kata tarcia wewnętrznego. Uwzględniono przy tym mechanizmy występujące w strefie ścięcia i ocenę bazowej wartości kąta tarcia [fi]B (rys.l), a w tym także wpływ nieregularności kształtu cząstek na wartości [fi]B Dla niskich naprężeń niezwykle pomocne są wyniki badań wytrzymałości gruntów na rozrywanie.

EN

This paper reviews the hypotheses of soils' strength and angle of internal friction interpretation for Mohr's curves envelopes. Maximovic's interpretation method was analyzed more precisely. The basic angle of friction [fi]B (fig-1) determined in the tests was used. The influence of interparticle mechanisms in the failure zone, and the role of angularity of particles shape in interlocking phenomena of particles were also explained. For interpretation of tests results at small stress [sigma]3, the role of soil resistance on tension was indicated.

9

Effects of soil moisture and nickel contamination on microbial respiration rates in heavy metal-polluted soils

63%

Morawska-Ploskonka J. , Niklinska M.

Polish Journal of Environmental Studies

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2013

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tom 22

|

nr 5

EN

Soil microorganisms may be both sensitive and resilient to various disturbances. The effects of a single stressor on soil microorganisms have been well studied, but only limited research has been carried out to test the effects of simultaneous action of diverse stressors. Soil samples were collected from a long-term polluted zinc and lead site and an unpolluted site. Modeling studies assumed spiking soils with five different concentrations of nickel (400, 800, 1.600, 3.200, and 6.400 mg Ni·kg⁻¹ dry weight soil) and their incubation under different humidity conditions (10%, 75%, and 120% of water holding capacity). We wanted to test if additional environmental disturbances have a different effect on microorganisms from polluted and unpolluted soils. The study showed that after 30 and 120 days of incubation, increasing Ni pollution inhibited microbial respiration rate (R), both in unpolluted and long-term metal polluted soils, irrespective of soil moisture. After 30 days of the experiment, microbial communities in both soils demonstrated a similar response to the additional toxicant. However, after 120 days of exposure to Ni, microbial communities from the unpolluted soil showed much higher inhibition of R than microbes from the polluted soils (p<0.001). The results might suggest that Ni co-tolerance mechanisms occurred in long-term metal polluted microbial communities.

10

Urease activity in soil contaminated with polycyclic aromatic hydrocarbons

51%

Lipinska A. , Kucharski J. , Wyszkowska J.

Polish Journal of Environmental Studies

|

2013

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tom 22

|

nr 5

EN

Urease activity was determined in soil contaminated with four polycyclic aromatic hydrocarbons (PAHs): naphthalene, phenanthrene, anthracene, and pyrene in the amount of 0, 1,000, 2,000, and 4,000 mg·kg⁻¹ DM soil. Organic materials – cellulose, sucrose, and compost – were applied to the samples in the amount of 0 and 9 g·kg⁻¹ DM soil. The experiment was carried out in a laboratory, and soil samples consisted of loamy sand. Soil resistance (RS) and soil resilience (RL) were determined. Soil contamination with PAHs had an adverse effect on urease activity, and naphthalene had the most inhibitory impact on the studied enzyme. Urease activity was significantly determined by the dose of PAH, soil incubation time, and the type of organic material. Soil resistance to PAHs decreased with an increase in contamination levels. The addition of sucrose, cellulose, and compost increased soil's resistance to the toxic effects of naphthalene and phenanthrene. Soil resilience values indicate that polycyclic aromatic hydrocarbons cause long-term impairment of urease activity.

11

Wykorzystanie naturalnej oporności gleb i podłoży oraz wyciągów roślinnych w ograniczeniu występowania chorób roślin ozdobnych

44%

Orlikowski L. B.

Progress in Plant Protection

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2010

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tom 50

|

nr 3

EN

A mixture of peat or composted pine bark with podsol or loam soils resulted in a significant decrease of development of Fusarium wilt of cyclamen and carnation. Amendment of peat with Fusaclean at the dose 1.6 g/l or Trichoderma spp. significantly inhibited the spread of Fusarium wilt of cyclamen and Phytophthora rot of gerbera. Regular fertilization of carnation with calcium and iron chelates strongly decreased the spread of Fusarium wilt. Amendment of medium with keratin-bark-urea extract already at the dose 1.6 μg/cm3 strongly inhibited sporulation of Phytophthora palmivora, whereas the application of extract at the dose 200 μg/cm3 as peperomia spray inhibited the development of necrotic spots on leaves about 75%. In vitro growth of Botrytis cinerea, Fusarium oxysporum f. sp. dianthi, Myrothecium roridum and Phytophthora cryptogea was inhibited from 45 to 100% when 500 μg/cm3 of Echinacea extract was added to PDA. The extract at the dose 0.1% used as Impatiens spray inhibited in 60% Myrothecium leaf spot development.