Hasil untuk "math-ph"

S. Ceci, W. Williams, Susan M. Barnett

Yang-Hui He, Vishnu Jejjala, B. Nelson

We apply techniques in natural language processing, computational linguistics, and machine-learning to investigate papers in hep-th and four related sections of the arXiv: hep-ph, hep-lat, gr-qc, and math-ph. All of the titles of papers in each of these sections, from the inception of the arXiv until the end of 2017, are extracted and treated as a corpus which we use to train the neural network Word2Vec. A comparative study of common n-grams, linear syntactical identities, word cloud and word similarities is carried out. We find notable scientific and sociological differences between the fields. In conjunction with support vector machines, we also show that the syntactic structure of the titles in different sub-fields of high energy and mathematical physics are sufficiently different that a neural network can perform a binary classification of formal versus phenomenological sections with 87.1% accuracy, and can perform a finer five-fold classification across all sections with 65.1% accuracy.

Joseph P. Robinson, S. Lubienski

Raquel Quendera, Maria João Nunes, Ana Luísa Fernando et al.

Anthropogenic CO₂ emissions drive ocean acidification through changes in the carbonate system, lowering seawater pH. In contrast, salinity variations arise from physical processes such as freshwater fluxes and circulation. This study reports the preparation and Harned cell characterization of three equimolal TRIS buffer solutions (0.01 mol·kg⁻¹, 0.025 mol·kg⁻¹, and 0.04 mol·kg⁻¹) in artificial seawater (ASW) matrices with practical salinities of 35 and 50 and temperatures of 20 °C, 25 °C, and 30 °C. Determined pH_T values achieved expanded uncertainties (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>U</mi></mrow><mrow><msub><mrow><mi mathvariant="normal">p</mi><mi mathvariant="normal">H</mi></mrow><mrow><mi mathvariant="normal">T</mi></mrow></msub></mrow></msub></mrow></semantics></math></inline-formula> ≤ 0.006), meeting Global Ocean Acidification Observing Network (GOA-ON) “climate” quality standards. Absolute salinity (<i>S</i>_A) was concurrently measured via density (TEOS-10), revealing systematic deviations from practical salinity due to TRIS content. A nonlinear regression model was developed to predict pH_T as a function of salinity, temperature, and TRIS molality, with <i>r</i>² = 0.99998. These results provide a robust dataset for developing Certified Reference Materials (CRMs) for pH_T calibration under climate-relevant high-salinity environments at different temperature conditions, offering a practical tool for high-accuracy calibration in variable marine conditions.

Marius Buliga

This is a reaction to the article Symplectic bipotentials, in published form [2] and in preprint form [1] arXiv:2410.23122v1. We give evidence that most of the content of the article [2] is already covered in previous works, partially cited like [7] arXiv:0810.1419 [math.FA], or uncited, like [10] arXiv:1902.04598 [math-ph], [3] arXiv:2304.14158 [math-ph], which already introduced and studied symplectic bipotentials.

J. Berthold, Hannes Keppler

We give the first and lowest order examples of 3-regular 3-edge-colored graphs that demonstrate the non-factorization of tensor model invariants in the large N limit of Gaussian random tensors, as proven on general grounds in [Gurau R., Joos F. and Sudakov B., Lett. Math. Phys., 115 (2025), arXiv:2506.15362 [math-ph]]. This non-factorization is in stark contrast to the well-known large N factorization for random matrices.

Hasan Akın

The q-state modified Potts model was originally introduced by Akin [H. Akin, arXiv:2504.17616 [math-ph]]. Unlike the classical Potts model, this modified version undergoes phase transitions solely in the antiferromagnetic regime, as rigorously demonstrated in [H. Akın, Chaos Solitons Fractals 199, 116746 (2025), doi:10.1016/j.chaos.2025.116746]. The formulation considered here constitutes a previously unexplored generalization within statistical mechanics. For clarity and consistency in future references, we refer to this construction as the q-state Akin model, thereby distinguishing it from conventional Potts-type models while recognizing its first rigorous definition in our earlier work. Building upon [H. Akın, Chaos Solitons Fractals 199, 116746 (2025), doi:10.1016/j.chaos.2025.116746], this study extends the thermodynamic analysis of the q-state Akin model on the Cayley tree. Employing the cavity method, we systematically derive the total partition function using recurrence relations that incorporate arbitrary q-spin configurations. From this framework, exact expressions for the free energy are obtained in terms of q, the external field h, the coupling constant J and the inverse temperature [Formula: see text]. Thermodynamic observables such as entropy, magnetization and susceptibility are then calculated as partial derivatives of the free energy. Through two- and three-dimensional graphical analyses, we identify critical phenomena including kinks, periodic oscillations and W-shaped peaks that arise at specific parameter values.

Offer Kopelevitch

We look at the eigenvalues of the complex Ginibre Ensemble of random matrices consisting of $N$ eigenvalues. We study the event that for $ {c \in [0,1]}$, $\lfloor cN \rfloor$ of the eigenvalues are located outside of a disk of radius $ R \in (\sqrt{1-c},1)$. Except for the case $c=1$ the eigenvalue process conditioned on this event is not determinantal. Nevertheless we are able to obtain asymptotic estimates of the probability of the event, and describe the conditional distribution in three spatial regions. For $ \{ \lambda \in \mathbb{C} : \big| \lambda \big|R+\epsilon\} $ the conditional distribution is asymptotically that of a Ginibre ensemble. Meanwhile, near the boundary of the disk, after rescaling by a factor of order $ N$, it tends to the determinantal point process that appears in the limit of the Ginibre ensemble near a hard wall in Seo arXiv:2010.08818 [math-ph] .

Nicolas Delporte, Giacomo La Scala, Naoki Sasakura et al.

We propose a new definition of characteristic polynomials of tensors based on a partition function of Grassmann variables. This new notion of characteristic polynomial addresses general tensors including totally antisymmetric ones, but not totally symmetric ones. Drawing an analogy with matrix eigenvalues obtained from the roots of their characteristic polynomials, we study the roots of our tensor characteristic polynomial. Unlike standard definitions of eigenvalues of tensors of dimension $N$ giving $\sim e^{{\text{constant}} \, N}$ number of eigenvalues, our polynomial always has $N$ roots. For random Gaussian tensors, the density of roots follows a generalized Wigner semi-circle law based on the Fuss-Catalan distribution, introduced previously by Gurau [arXiv:2004.02660 [math-ph]].

Rabia Şemsi, Aylin Sepici Dinçel

Objective: Biochemistry is a vast and multidisciplinary field of research that encompasses the study of chemical processes in living organisms. Undergraduate biochemistry laboratory courses include practicals that require students to use laboratory math skills, such as pH, absorbance, concentration, dilution and solution calculations. This study investigated the impact of incorporating practical tests into biochemistry laboratory practice on student success and aimed to explore the correlation between student learning styles and academic achievements. Materials and Methods: The study population consisted on 235 Year I students, 43.4% male (n=102) and 56.6% female (n=133) from the Medical Faculty at Gazi University and Kyrenia University, with an average age of 19.87±1.81. The study was conducted as a descriptive and cross-sectional study, and the quantitative data was collected from pretest and posttest measures. Results:There was a significant difference between pre-¬test and post¬-test scores (p<0.001), i

Yogendra Singh, Sandhya Chaudhary, Ravi Kant

This study assessed the Ganga River's water quality in the Aligarh District in relation to industrial wastes.Between May and June 2024,data were gathered from six sample stations that included upstream,downstream, and midstream areas. Ex situ examinations (of absolute phosphorus [TP], substance oxygen request [COD], complete nitrogen [TN], organic oxygen request [BOD] and all out disintegrated solids [TDS]),and were done notwithstanding in situ perceptions (of all out suspended solids [TSS], electrical conductivity [EC], temperature and pH,).The whole water quality was assessed using the weighted math water quality index (WQI). Massive contrasts in the water quality indicators between the sampling locales were tracked down by measurable analysis.Notably,pH values at two sites were higher than what the MoEF,and WHO considered to be acceptable.The river water was classified as "unsuitable for consumption" by the WQI results.Significant pollution is evident from the observed fluctuations in indices like COD,BOD,TN,TP,and TSS,which are mostly caused by industrial emissions.These results emphasize how urgently better pollution control and wastewater management strategies are needed. The study offers the municipal administration of Aligarh useful information for creating plans for efficiently managing and preserving the Ganga River,guaranteeing its sustainability and preserving public health.

Muhammad Saqib Rashid, Yanhong Wang, Yilong Yin et al.

Soil pollution with cadmium (Cd) poses serious health and environmental consequences. The study investigated the incubation of several soil samples and conducted quantitative soil characterization to assess the influence of biochar (BC) on Cd adsorption. The aim was to develop predictive models for Cd concentrations using statistical and modeling approaches dependent on soil characteristics. The potential risk linked to the transformation and immobilization of Cd adsorption by BC in the soil could be conservatively assessed by pH, clay, cation exchange capacity, organic carbon, and electrical conductivity. In this study, Long Short-Term Memory (LSTM), Bidirectional Gated Recurrent Unit (BiGRU), and 5-layer CNN Convolutional Neural Networks (CNNs) were applied for risk assessments to establish a framework for evaluating Cd risk in BC amended soils to predict Cd transformation. In the case of control soils (CK), the BiGRU model showed commendable performance, with an <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> value of 0.85, indicating an approximate 85.37% variance in the actual Cd. The LSTM model, which incorporates sequence data, produced less accurate results (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0.84</mn><mo>)</mo></mrow></semantics></math></inline-formula>, while the 5-layer CNN model had an <i>R</i>² value of 0.91, indicating that the CNN model could account for over 91% of the variation in actual Cd levels. In the case of BC-applied soils, the BiGRU model demonstrated a strong correlation between predicted and actual values with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> (0.93), indicating that the model explained 93.21% of the variance in Cd concentrations. Similarly, the LSTM model showed a notable increase in performance with BC-treated soil data. The <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> value for this model stands at a robust <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> </mo><mo>(</mo><mn>0.94</mn><mo>)</mo></mrow></semantics></math></inline-formula>, reflecting its enhanced ability to predict Cd levels with BC incorporation. Outperforming both recurrent models, the 5-layer CNN model attained the highest precision with an <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> value of 0.95, suggesting that 95.58% of the variance in the actual Cd data can be explained by the CNN model’s predictions in BC-amended soils. Consequently, this study suggests developing ecological soil remediation strategies that can effectively manage heavy metal pollution in soils for environmental sustainability.

M. C. Ringham, M. C. Ringham, N. Hirtle et al.

<p>Ocean alkalinity enhancement (OAE) is a promising approach to marine carbon dioxide removal (mCDR) that leverages the large surface area and carbon storage capacity of the oceans to sequester atmospheric <span class="inline-formula">CO₂</span> as dissolved bicarbonate (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><msub><mi mathvariant="normal">HCO</mi><mn mathvariant="normal">3</mn></msub><mo>-</mo></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="38pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="f7f7a137c195a83f06f2ec9ae074733a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-21-3551-2024-ie00001.svg" width="38pt" height="15pt" src="bg-21-3551-2024-ie00001.png"/></svg:svg></span></span>). One OAE method involves the conversion of salt in seawater into aqueous alkalinity (NaOH), which is returned to the ocean. The resulting increase in seawater pH and alkalinity causes a shift in dissolved inorganic carbon (DIC) speciation toward carbonate and a decrease in the surface ocean <span class="inline-formula"><i>p</i></span><span class="inline-formula">CO₂</span>. The shift in the <span class="inline-formula"><i>p</i></span><span class="inline-formula">CO₂</span> results in enhanced uptake of atmospheric <span class="inline-formula">CO₂</span> by the seawater due to gas exchange. In this study, we systematically test the efficiency of <span class="inline-formula">CO₂</span> uptake in seawater treated with NaOH at aquarium (15 L) and tank (6000 L) scales to establish operational boundaries for safety and efficiency in advance of scaling up to field experiments. <span class="inline-formula">CO₂</span> equilibration occurred on the order of weeks to months, depending on circulation, air forcing, and air bubbling conditions within the test tanks. An increase of <span class="inline-formula">∼0.7</span>–0.9 mol DIC per mol added alkalinity (in the form of NaOH) was observed through analysis of seawater bottle samples and pH sensor data, consistent with the value expected given the values of the carbonate system equilibrium calculations for the range of salinities and temperatures tested. Mineral precipitation occurred when the bulk seawater pH exceeded 10.0 and <span class="inline-formula">Ω_aragonite</span> exceeded 30.0. This precipitation was dominated by <span class="inline-formula">Mg(OH)₂</span> over hours to 1 d before shifting to <span class="inline-formula">CaCO_3,aragonite</span> precipitation. These data, combined with models of the dilution and advection of alkaline plumes, will allow the estimation of the amount of carbon dioxide removal expected from OAE pilot studies. Future experiments should better approximate field conditions including sediment interactions, biological activity, ocean circulation, air–sea gas exchange rates, and mixing zone dynamics.</p>

J. M. Roberts, S. Wang, S. Wang et al.

<p><span id="page3422"/>Bromine activation (the production of <span class="inline-formula">Br</span> in an elevated oxidation state) promotes ozone destruction and mercury removal in the global troposphere and commonly occurs in both springtime polar boundary layers, often accompanied by nearly complete ozone destruction. The chemistry and budget of active bromine compounds (e.g., <span class="inline-formula">Br₂</span>, <span class="inline-formula">BrCl</span>, <span class="inline-formula">BrO</span>, <span class="inline-formula">HOBr</span>) reflect the cycling of <span class="inline-formula">Br</span> and affect its environmental impact. Cyanogen bromide (<span class="inline-formula">BrCN</span>) has recently been measured by iodide ion high-resolution time-of-flight mass spectrometry (<span class="inline-formula">I⁻</span> CIMS), and trifluoro methoxide ion time-of-flight mass spectrometry (<span class="inline-formula">CF₃O⁻</span> CIMS) during the NASA Atmospheric Tomography Mission second, third, and fourth deployments (NASA ATom), and could be a previously unquantified participant in active <span class="inline-formula">Br</span> chemistry. <span class="inline-formula">BrCN</span> mixing ratios ranged from below the detection limit (1.5 <span class="inline-formula">pptv</span>) up to as high as 36 <span class="inline-formula">pptv</span> (10 <span class="inline-formula">s</span> average) and enhancements were almost exclusively confined to the polar boundary layers in the Arctic winter and in both polar regions during spring and fall. The coincidence of <span class="inline-formula">BrCN</span> with active <span class="inline-formula">Br</span> chemistry (often observable <span class="inline-formula">BrO</span>, <span class="inline-formula">BrCl</span> and <span class="inline-formula">O₃</span> loss) and high <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M22" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><msub><mi mathvariant="normal">CHBr</mi><mn mathvariant="normal">3</mn></msub></mrow><mo>/</mo><mrow class="chem"><msub><mi mathvariant="normal">CH</mi><mn mathvariant="normal">2</mn></msub><msub><mi mathvariant="normal">Br</mi><mn mathvariant="normal">2</mn></msub></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="76pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="f9c2c577e80b58a3c7d171e37d26f4c3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-3421-2024-ie00001.svg" width="76pt" height="14pt" src="acp-24-3421-2024-ie00001.png"/></svg:svg></span></span> ratios imply that much of the observed <span class="inline-formula">BrCN</span> is from atmospheric <span class="inline-formula">Br</span> chemistry rather than a biogenic source. Likely <span class="inline-formula">BrCN</span> formation pathways involve the heterogeneous reactions of active <span class="inline-formula">Br</span> (<span class="inline-formula">Br₂</span>, <span class="inline-formula">HOBr</span>) with reduced nitrogen compounds, for example hydrogen cyanide (<span class="inline-formula">HCN</span><span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M30" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5c3774ab0600a2f03e83f0e636ae5ed2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-3421-2024-ie00002.svg" width="8pt" height="14pt" src="acp-24-3421-2024-ie00002.png"/></svg:svg></span></span><span class="inline-formula">CN⁻</span>), on snow, ice, or particle surfaces. Competitive reaction calculations of <span class="inline-formula">HOBr</span> reactions with <span class="inline-formula">Cl⁻</span><span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M34" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="64e9f3179c4b320c75002019e5b7cf16"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-3421-2024-ie00003.svg" width="8pt" height="14pt" src="acp-24-3421-2024-ie00003.png"/></svg:svg></span></span><span class="inline-formula">Br⁻</span> and <span class="inline-formula">HCN</span><span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M37" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="f77694ccc584f068782523cf5fd7b6a6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-3421-2024-ie00004.svg" width="8pt" height="14pt" src="acp-24-3421-2024-ie00004.png"/></svg:svg></span></span><span class="inline-formula">CN⁻</span> in solution, as well as box model calculations with bromine chemistry, confirm the viability of this formation channel and show a distinct pH dependence, with <span class="inline-formula">BrCN</span> formation favored at higher pH values. Gas-phase loss processes of <span class="inline-formula">BrCN</span> due to reaction with radical species are likely quite slow and photolysis is known to be relatively slow (<span class="inline-formula">BrCN</span> lifetime of <span class="inline-formula">∼</span> 4 months in midlatitude summer). These features, and the lack of <span class="inline-formula">BrCN</span> enhancements above the polar boundary layer, imply that surface reactions must be the major loss processes. The fate of <span class="inline-formula">BrCN</span> determines whether <span class="inline-formula">BrCN</span> production fuels or terminates bromine activation. <span class="inline-formula">BrCN</span> reactions with other halogens (<span class="inline-formula">Br⁻</span>, <span class="inline-formula">HOCl</span>, <span class="inline-formula">HOBr</span>) may perpetuate the active <span class="inline-formula">Br</span> cycle; however, preliminary laboratory experiments showed that <span class="inline-formula">BrCN</span> did not react with aqueous bromide ion (<span class="inline-formula">&lt;</span> 0.1 %) to reform <span class="inline-formula">Br₂</span>. Liquid-phase reactions of <span class="inline-formula">BrCN</span> are more likely to convert <span class="inline-formula">Br</span> to bromide (<span class="inline-formula">Br⁻</span>) or form a <span class="inline-formula">C</span>–<span class="inline-formula">Br</span> bonded organic species, as these are the known condensed-phase reactions of <span class="inline-formula">BrCN</span> and would therefore constitute a loss of atmospheric active Br. Thus, further study of the chemistry of <span class="inline-formula">BrCN</span> will be important for diagnosing polar <span class="inline-formula">Br</span> cycling.</p>

Enhui Ji, Minglong Fang, Haixia Wu

Phosphorus mainly exists in the form of phosphate in water. Excessive phosphorus can cause eutrophication, leading to algae reproduction and the depletion of oxygen in water, destroying aquatic ecology. This study prepared quaternized polyaniline (PN) and quaternized polyaniline with lanthanum hydrate (HLO-PN), and a new nanocomposite for removing phosphate from wastewater was proposed. The results of adsorption experiments show that HLO-PN can effectively remove phosphate in the range of pH 3~7; the maximum adsorption capacity is 92.57 mg/g, and it has excellent anti-interference ability against some common coexisting anions (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi mathvariant="normal">F</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>,</mo></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi mathvariant="normal">C</mi><mi mathvariant="normal">l</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>,</mo></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>NO</mi></mrow><mrow><mn>3</mn></mrow><mrow><mo>−</mo></mrow></msubsup><mo>,</mo></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>SO</mi></mrow><mrow><mn>4</mn></mrow><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow></semantics></math></inline-formula>) other than <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>CO</mi></mrow><mrow><mn>3</mn></mrow><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow></semantics></math></inline-formula>. After five adsorption–desorption cycles, the phosphate adsorption capacity (60 mg/g) was still 74.28% of the initial adsorption capacity (80.85 mg/g), indicating that the HLO-PN nanocomposites had good reusability and recovery of phosphorus. The characterization results show that phosphate adsorption is realized by electrostatic adsorption and ligand exchange.

LI Mengyan, QI Mengyu, WU Jialong et al.

This study explored and evaluated the adsorption capacity of graphitized carbon black (GCB) to remove enrofloxacin (ENR) in an aquaculture environment. GCB was characterized by scanning electron microscope, Fourier transform infrared spectrometer, Raman spectrum and Zeta potential. Additionally, the effects of pH value, adsorption temperature (T), initial concentration of ENR (C₀) and adsorption time (t) on the adsorption of ENR by GCB were determined. Meanwhile, the adsorption thermodynamics and adsorption kinetics of ENR by GCB were explored to reveal its adsorption mechanisms. The results showed that GCB had good adsorption performance to ENR, which can be described by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model. Under the conditions of <inline-formula><alternatives><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mi mathvariant="normal">p</mml:mi><mml:mi mathvariant="normal">H</mml:mi></mml:math><inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/CA0670B4-087A-463a-88EB-FC504D1834F3-M004c.jpg"/></alternatives></inline-formula>=7, <inline-formula><alternatives><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:mn mathvariant="normal">0</mml:mn></mml:mrow></mml:msub></mml:math><inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/CA0670B4-087A-463a-88EB-FC504D1834F3-M005c.jpg"/></alternatives></inline-formula>=200 mg/L and <inline-formula><alternatives><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mi>T</mml:mi></mml:math><inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/CA0670B4-087A-463a-88EB-FC504D1834F3-M006c.jpg"/></alternatives></inline-formula>=35 ℃, GCB had the strongest adsorption capacity for ENR in solution, and the maximum adsorption quantity could reach 74.43 mg/g. Furthermore, it was found that GCB demonstrated good adsorption quantity on ENR residues in actual spiked cultural freshwater and spiked cultural seawater, and the unit adsorption quantities were (32.47±0.99) mg/g and (31.84±1.46) mg/g, respectively. In conclusion, GCB has the potential to remove ENR from real aquaculture tailwater.

A.-M. Virkkala, A.-M. Virkkala, P. Niittynen et al.

<p>Arctic terrestrial greenhouse gas (GHG) fluxes of carbon dioxide (CO<span class="inline-formula">₂</span>), methane (CH<span class="inline-formula">₄</span>), and nitrous oxide (N<span class="inline-formula">₂</span>O) play an important role in the global GHG budget. However, these GHG fluxes are rarely studied simultaneously, and our understanding of the conditions controlling them across spatial gradients is limited. Here, we explore the magnitudes and drivers of GHG fluxes across fine-scale terrestrial gradients during the peak growing season (July) in sub-Arctic Finland. We measured chamber-derived GHG fluxes and soil temperature, soil moisture, soil organic carbon and nitrogen stocks, soil pH, soil carbon-to-nitrogen (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">C</mi><mo>/</mo><mi mathvariant="normal">N</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="a1fd226718b6fd2378e4d645ff1b8807"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-21-335-2024-ie00001.svg" width="24pt" height="14pt" src="bg-21-335-2024-ie00001.png"/></svg:svg></span></span>) ratio, soil dissolved organic carbon content, vascular plant biomass, and vegetation type from 101 plots scattered across a heterogeneous tundra landscape (5 km<span class="inline-formula">²</span>). We used these field data together with high-resolution remote sensing data to develop machine learning models for predicting (i.e., upscaling) daytime GHG fluxes across the landscape at 2 m resolution. Our results show that this region was on average a daytime net GHG sink during the growing season. Although our results suggest that this sink was driven by CO<span class="inline-formula">₂</span> uptake, it also revealed small but widespread CH<span class="inline-formula">₄</span> uptake in upland vegetation types, almost surpassing the high wetland CH<span class="inline-formula">₄</span> emissions at the landscape scale. Average N<span class="inline-formula">₂</span>O fluxes were negligible. CO<span class="inline-formula">₂</span> fluxes were controlled primarily by annual average soil temperature and biomass (both increase net sink) and vegetation type, CH<span class="inline-formula">₄</span> fluxes by soil moisture (increases net emissions) and vegetation type, and N<span class="inline-formula">₂</span>O fluxes by soil <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">C</mi><mo>/</mo><mi mathvariant="normal">N</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5eeb1c5cb631cedd0f3a8dec9feeaf61"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-21-335-2024-ie00002.svg" width="24pt" height="14pt" src="bg-21-335-2024-ie00002.png"/></svg:svg></span></span> (lower <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">C</mi><mo>/</mo><mi mathvariant="normal">N</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="9a0fb47100c852e2eda5b51d5d8036ea"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-21-335-2024-ie00003.svg" width="24pt" height="14pt" src="bg-21-335-2024-ie00003.png"/></svg:svg></span></span> increases net source). These results demonstrate the potential of high spatial resolution modeling of GHG fluxes in the Arctic. They also reveal the dominant role of CO<span class="inline-formula">₂</span> fluxes across the tundra landscape but suggest that CH<span class="inline-formula">₄</span> uptake in dry upland soils might play a significant role in the regional GHG budget.</p>

Sabrina Hempel, Huyen Vu, Thomas Amon et al.

Ammonia emission rates from naturally ventilated livestock housing systems can be estimated in multiple ways. By coupling different modeling approaches towards a semi-mechanistic barn-scale ammonia emission model, we investigated the influence of urine puddle pH dynamics on the (sub)daily and seasonal pattern of ammonia emissions. We compared the simulated ammonia emission patterns using about ten months of on-farm measurements obtained from a naturally ventilated dairy cattle building with a scraped solid floor in Northern Germany. The dataset included gas concentration measurements as well as wind data (ranging from 0 m s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> to about 8.6 m s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>) and air temperature data (ranging from about −4 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula>C to about 32 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mo>∘</mo></msup></semantics></math></inline-formula>C), the average number of housed cows (about 380) and information on the average cow mass (about 700 kg). In addition, the average dry matter intake, total gross energy intake and nitrogen intake were used to model the ammonia emission potential. In the emission modeling, we considered two potential types of pH dynamics in the urine puddles: a saturating scenario and a peaking scenario. For both of them, 21 different combinations of initial pH and maximum pH were considered within a range of 6.5 to 11. We showed that the non-linear interaction of the puddle pH and temperature caused specific emission patterns, where the degree of influence of the two parameters changed over the course of the emission process. Low initial pH values together with high asymptotic pH values were associated with the largest emissions. Considering the same asymptotic pH value, the higher the initial pH value, the lower the observed emissions; especially when assuming peak pH dynamics, the emission values were significantly lower. In natural pH settings (i.e., low to intermediate initial pH and intermediate asymptotic pH), the winter emissions were considerably lower than the summer emissions (i.e., the winter emission was about half of the summer emission, as observed in the on-farm studies). In contrast, artificial pH settings with high pH values led to markedly lower emissions in the summer (i.e., the summer emission was about the same as winter emission), reducing the total annual emission value. Our sensitivity study indicated that the urine puddle alkalizing dynamics play a key role in the overall emission model accuracy in order to capture seasonal and diurnal variability of the ammonia emission of naturally ventilated dairy cattle barns in mechanistic modeling approaches. Thus, future studies should investigate the range of pH dynamics that naturally occur in urine puddles in cattle barns depending on the flooring material, the entry of litter or feed leftovers, the cleaning and cooling system (e.g., in terms of use of water) and so on in order to further refine the emission model.

Jianwei Wei, Menghua Wang, Karlis Mikelsons et al.

This study investigates the seasonal and regional variability in the chlorophyll-specific absorption coefficient of phytoplankton at 443 nm (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula>; unit: m² mg⁻¹) in surface oceans. It is focused on the time series data derived from the satellite products of chlorophyll-a (Chl-a) concentration and the phytoplankton absorption coefficient. Global estimates of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> reveal a decreasing gradient from the open ocean toward the coastal environment, with considerable spatial variance. Seasonal variations are prominent over most oceans, resulting in substantial deviations from the climatological means. A sinusoidal model was fitted to the monthly time series data to characterize the annual and semiannual features. The amplitudes and the phases of the monthly data were latitudinally dependent. The occurrence times of the maximum <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> values were six months out of phase between the northern and southern hemispheres. Satellite observations present a global mean relationship between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> and Chl-a comparable with those obtained via in situ measurements. However, the seasonal/regional <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> and Chl-a relationships can significantly depart from the global mean relationship. We propose a hypothesis that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>a</mi></mrow><mrow><mi mathvariant="italic">ph</mi></mrow><mrow><mo>*</mo></mrow></msubsup><mrow><mo stretchy="false">(</mo><mn>443</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> can be predicted as a function of geolocation and time. Preliminary validations with in situ matchup data confirm that the proposed model is a promising alternative to the traditional approaches requiring Chl-a as the input. The present exploration helps understand the phytoplankton biogeography and facilitates future efforts to improve bio-optical modeling, including estimating the primary production.

Rajesh Mahadeva, Mahendra Kumar, Shashikant P. Patole et al.

Desalination plants have an important concern regarding controlling the permeate flow rate and pH during operability. This paper proposes the proportional integral derivative (PID) control design using modified Particle Swarm Optimization (PSO) techniques called autonomous groups PSO (AGPSO) in the two-input two-output (TITO) RO desalination plant to control the permeate flow rate and pH. Here, three different versions (AGPSO1, AGPSO2, and AGPSO3) of the AGPSO algorithm are utilized to design PID control for the same TITO plant. In addition, an integral time absolute error (<inline-formula> <tex-math notation="LaTeX">$J_{\mathrm {ITAE}}$ </tex-math></inline-formula>) based objective function is utilized to design a PID controller. The simulation results suggest that the proposed controller designs are flexible, self-tuning, and have stable characteristics, while the AGPSO3-PID control design attained a robust design for optimum tuning compared to existing improved grey wolf optimization PID (IGWO-PID) and other versions of AGPSO based PIDs (AGPSO1-PID, AGPSO2-PID). The design of AGPSO-PID achieved a minimum objective function than existing IGWO-PID and other versions of AGPSO based PIDs &#x007B;AGPSO1-PID, AGPSO2-PID&#x007D;. Finally, the proposed controller designs outperform the existing IGWO-PID design in literature in terms of control performance, demonstrating a precise control for and the improvement of plant performance.