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1

The Chlorophyll-a Response of Phytoplankton to Ratio N/P in Different Coastal Waters

Maslukah Lilik, Handoyo Gentur, Wulandari Sri Yulina, Sihite Catherine Berliana, Sarjito

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 9

121--129

EN

Phytoplankton growth is influenced by the presence of nutrients N (nitrogen) and P (phosphor). Each region has a specific N/P ratio, due to the influence of anthropogenic inputs. This study aimed to assess the response of phytoplankton chlorophyll-a (Chl-a) biomass due to differences in N/P ratio by the influence of river flow in the north coast of Java; Jobokuto Bay (Jepara), the coastal waters of Semarang and the front of the Cisadane river. N-nutrients were analyzed in the form of N-NO3 (nitrate), and N-NH4+ (ammonium ions), and orthophosphate ions (P-PO42-). Nutrient analysis was spectrometric, using the reduction methods (nitrate), ammonium (indophenolblue), and phosphate (molybdenum-blue). Test for site differences using Kruskall-Wallis, followed by a posthoc test. The results showed that Semarang waters had a lower N/P (Stoichiometric) ratio than Jepara and Cisadane, which can be used to predict that P nutrient input is higher than N. This high P input impacts microalgal development (chlorophyll-a). In addition, we also found Semarang waters to have higher speciation of inorganic N in the form of ammonium, which is one of the drivers of eutrophication in these waters. The use of a ratio of N/P is very important in estimating the eutrophication process and can be used to estimate the dominance of nutrients entering the water due to anthropogenic activities in the upstream area.

2

Fuel saving index assessment on driving behavior control system of prototype model using neural network

Munahar Suroto, Triwiyatno Aris, Munadi M., Setiavan Joga Dharma

Archives of Transport

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2022

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Vol. 63, iss. 3

123--141

EN

Efficient fuel consumption in the world is essential in automotive technology development due to the increase in vehicle usage and the decrease in global oil production. Several studies have been conducted to increase fuel consumption savings, Fuel Cells (FCs), the application of alternative energy vehicles and the Engine Control Unit (ECU) system. FCs do not require oil energy to propel the vehicle, so this technology promises to reduce energy consumption and emissions. However, this research still leaves problems. FCs are susceptible to short circuit hazards, and ownership costs are very high. Alternative energy applications produce less power, less responsive acceleration, and insufficient energy sources to enter mass production. The ECU application still has an orientation toward achieving stoichiometry values, so the increase in fuel efficiency has the potential to be improved. Driving behavior is a variable that has a close relationship with fuel consumption efficiency. However, research on driving behavior is only studied for implementation in autonomous car-following technologies, safety systems, charging needs characteristic of electric vehicles, emission controls, and display images on invehicle information systems. Meanwhile, research on driving behavior as a control system to improve fuel efficiency has not been carried out. To that end, this study proposes the use of driving behavior for a newly designed control system to improve fuel efficiency. The control system in this research is a prototype model to be assessed using the Fuel Saving Index (FSI) analysis. An artificial neural network is used to help the recognition of driving behavior. The results showed that the newly designed control system was categorized on scale IV of FSI. On this scale, the power generated by the engine is quite optimal when it is in the eco-scheme driving behavior. The driving behavior control system can significantly improve the efficiency of fuel consumption. Air to Fuel Ratio (AFR) is achieved above the stoichiometric value.

3

Influence of Branch Death on Leaf Nutrient Status and Stoichiometry of Wild Apple Trees (Malus sieversii) in the Western Tianshan Mountains, China

Tao Ye, Nuerhailati Maziyirea, Zhang Yuan-Ming, Zhang Jing, Yin Ben-Feng, Zhou Xiao-Bing

Polish Journal of Ecology

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2020

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Vol. 68, nr 4

296--312

EN

The wild apple tree Malus sieversii is a tertiary relict species and a key ancestor of the commonly cultivated apple trees today. In recent years, many M. sieversii individuals have died or have severe dead branches. Whether branch death would lead to the change in nutrient stoichiometry of M. sieversii remains unclear. In this study, the nitrogen (N), phosphorous (P), and potassium (K) stoichiometric traits of M. sieversii individual trees with different proportion of dead branches divided into three classes (Class I [< 20%], Class II [40-60%], and Class III [> 80%]) during annual growth period, elemental scaling relations, and the possible influencing factors were systematically analysed. Leaf N, P, and K decreased during growing season, and N and P did not show significant differences among the three classes; however, the Class III wild apple trees had the lowest K contents in both photosynthetic and reproductive organs. Flowers had higher P and K contents than leaves, whereas fruits had low N content. The growth of M. sieversii was always limited by N due to low N:P ratio and N resorption efficiency. The scaling exponents of leaf N-P, N-K, or P-K among the three classes did not show any significant differences, revealing an inherent property of M. sieversii. Most soil variables showed weak correlations with leaf nutrient parameters (except for K). Precipitation and relative humidity, rather than temperature, showed significantly positive effects on leaf nutrients. These findings suggest that increasing water input and plant K content may be conducive to enhance the resistance and recovery ability of diseased wild apple trees.

4

Nutrient stochiometric relations and biogeochemical niche in coexisting plant species : effect of simulated climate change

Penuelas J., Sardans J., Ogaya R., Estiarte M.

Polish Journal of Ecology

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2008

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Vol. 56, nr 4

613-622

EN

Here we define a "biogeochemical niche" characterized by the species position in the multivariate space generated by its content not only of macronutrients like N, P or K, but also of micronutrients such as Mo, Mg and Ca, and trace toxic elements such as Pb and As. We then hypothesize that the flexibility of the species "biogeochemical niche" will influence the quality of plant tissue, which may have implications for herbivores, and will affect the species capacity to respond to disturbances and climate change and to adapt to the new climate conditions. We show with a simple multivariate procedure, a principal component analysis (PCA), first, that there is a strong differentiation in the total and relative (stoichiometry) content of the different elements in coexisting plant species, and, second, that there is species-specific plasticity in the response of this elemental composition to experimental climate change. The concentrations of foliar macro and micronutrients, as well as trace elements were measured in several tree species (Quercus ilex L., Phillyrea latifolia L. and Arbutus unedo L. in a Mediterranean broad leaf forest (Prades Mts) and in shrub species (Erica multiflora L., Globularia alypum L. and Dorycnium pentaphyllum Scop.) in a Mediterranean shrubland (Garraf Mts) in control plants and in plants grown in experimental drought and warming plots. The climate conditions were monitored during the period 1999-2005. During this period, in the Prades experiment the drought plots had on average a soil moisture content 9% lower than the control plots, whereas in the Garraf experiment the drought treatment led to a mean reduction in soil moisture of 21% and the warming treatment to 0.9 [degree]C rise. The species with greater changes in biogeochemical niche under increased warming or drought, Arbutus unedo, Erica multiflora and Globularia alypum, were those that were also more affected in growth, photosynthetic capacity and other eco-physiological traits. The species differentiations indicate a strong biogeochemical niche, and that the changes in biogeochemical niche are probably an underlying factor in community structure shifts.

5

Stechiometria i kinetyka procesów metabolicznych wybranych drobnoustrojów

Krzystek L.

Zeszyty Naukowe. Rozprawy Naukowe / Politechnika Łódzka

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2002

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Z. 303

5-114

PL

Podstawą ilościowej analizy metabolizmu drobnoustrojów jest formułowanie stechiometrii indywidualnych reakcji, a następnie szlaków metabolicznych, które stanowią punkt wyjścia dla przeprowadzenia bilansów masy i energii. Umożliwia to opracowywanie metod ekonomicznego planowania i kierowania procesem produkcyjnym oraz matematycznego opisu przebiegu danego procesu. W opracowaniu zawarto założenia teoretyczne oraz praktyczne zastosowanie bilansów masy i energii. Omówiona została stechiometria bioprocesów, wyprowadzono ogólne zależności dla bilansów masy i energii do opisu metabolicznego wzrostu drobnoustrojów i tworzenia produktów. Wyjaśniono znaczenie wynikających z bilansów współczynników wydajności oraz zależności między współczynnikami stechiometrycznymi a doświadczalnymi współczynnikami wydajności. Analizowano ograniczenia dla teoretycznych współczynników wydajności biomasy i produktów w bioprocesach. Przedstawiono analizę zgodności danych doświadczalnych na podstawie prostego modelu metabolicznego, uzupełnioną o zaproponowaną zależność opisującą wykorzystanie energii w postaci ATP. Przedstawiono również zastosowanie bilansów w analizie kinetycznej procesów metabolicznych. Teorie tę zilustrowano przykładami procesu wytwarzania biomasy Kluyveromyces fragilis, produkcji etanolu przez Saccharomyces cerevisiae oraz produkcji kwasu cytrynowego przez Aspergillus niger. Na podstawie przeprowadzonych badań doświadczalnych, uwzględniając specyfikę powyższych procesów, sformułowano stechiometrię, bilanse masy i energii, wyznaczono współczynniki wydajności. Sprawdzono zgodność otrzymanych wyników i prawidłowość przebiegu procesu. Wyznaczono zapotrzebowanie energii na procesy przemiany podstawowej i porównano z danymi literaturowymi. Uzyskano bardzo dobrą zgodność wyników obliczeń teoretycznych i danych doświadczalnych. Opracowano model kinetyczny opisujący przebieg procesu wytwarzania kwasu cytrynowego przez Aspergillus niger. Zaproponowana stechiometria obejmuje zarówno procesy zachodzące podczas wzrostu pleśni jak i produkcji kwasu cytrynowego. Do opisu większości szybkości reakcji zastosowano zależność Michaelis'a-Menten oraz odpowiednie równania kinetyczne uwzględniające inhibicję. Przeprowadzono obiczenia symulacyjne dla procesu okresowego i stwierdzono, że zaproponowany model matematyczny bardzo dobrze odzwierciedla charakter zmian stężeń analizowanych substratów i produktów.

EN

A quantitative analysis of the metabolism of microorganisms is based on formulation of the stoichiometry of individual reactions, and next metabolic pathways which constitute a basis for mass and energy balances. This enables a development of the methods of economic planning and management of production processes and mathematical description of particular processes. The study presents theoretical assumptions and practical applications of mass and energy balances. Stoichiometry of bioprocesses was discussed, general relationships for mass and energy balances were derived for the description of metabolic growth of microorganisms and product formation. The significance of yield coefficients resulting from the balances and relations between stoichiometric coefficients and experimental yield coefficients were explained. Restrictions for theoretical yield coefficients of biomass and products during bioprocesses were analyzed. Agreement of experimental data was analyzed using a simple metabolic model completed with a proposed relation describing the recovery of energy in the form of ATP. Applications of the balances in the kinetic analysis of metabolic processes were presented. This theory was illustrated by examples of the process of production of Kluyveromyces fragilis biomass, ethanbl production by Saccharomyces cerevisiae and citric acid production by Aspergillus niger. On the basis of experimental investigations, taking into account characteristics of these processes, the stoichiometry and mass and energy balances were formulated, and yield coefficients were determined. Agreement of the results and correctness of the process was checked. Energy demand for basic metabolic processes was determined and compared with theoretical data. Very good agreement of the results of theoretical calculations and experimental data was obtained. A kinetic model which described citric acid production by A. niger was developed. The proposed stoichiometry covers both the processes which take place during mould growth and citric acid accumulation. For the description of most reaction rates the Michaelis-Menten kinetics and relevant kinetic equations taking into account the inhibition were used. A simulation was made for a batch process and it was found that it illustrated very well the character of changes in experimental data.

6

On the defect structure of alkaline earth titanates.

Komornicki S.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

819-822

EN

Nonstoichiometry in strontium titanate as an example of alkaline earth titanates was discussed in terms of Sr/Ti ratio and dopant concentration and extended defect existence. For some dopant concentrations and titanium or strontium excess a self-compensation of cation and anion vacancies could be observed, leading to unusual pressure dependencies of electrical conductivity.