Artykuły w czasopismach na temat „Micro-doc”
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Santos, Tulio Gonçalves dos, Ricardo Santos Silva Amorim, Edwaldo Dias Bocuti, Oscarlina Lúcia dos Santos Weber i Letycia Cunha Nunes. "Dissolved organic carbon and nitrate flows in two micro-watersheds with different land uses". Semina: Ciências Agrárias 42, nr 2 (24.02.2021): 553–64. http://dx.doi.org/10.5433/1679-0359.2021v42n2p553.
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he impacts of human activities on watersheds can change the quality and possible uses of water resources. In this context, we evaluated the flows of dissolved organic carbon (DOC) and nitrate (NO3) in the surface waters of two micro-watersheds with different anthropic impacts. Water samples were collected from two micro-watersheds with different land uses (regenerated savanna and an agricultural site) from January 2014 to April 2015. In the rainy season, the samples were collected every 15 days, while in the dry season, samples were collected every 30 days. An automatic sampler in the stream collected the composed samples. Water flow was monitored with a sensor that measured the hydraulic load on the sill of the triangular spillway installed in each micro-watershed. The DOC and NO3 contents were analyze via UV-Vis spectrophotometry. The flow was estimated based on the DOC and NO3 flows and concentrations. The DOC concentrations were higher in the Cerrado micro-watershed; however, there was no difference in NO3 concentrations. In both watersheds, there was a significant increase in the concentrations of DOC and NO3 on rainy days, with was more pronounced in the agricultural watershed. The DOC and NO3 flows were higher in the micro-watershed with Cerrado vegetation on days with rain; while on days without rain, there was no difference.
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Abdelsalam i Diab. "Optimal Coordination of DOC Relays Incorporated into a Distributed Generation-Based Micro-grid Using a Meta-Heuristic MVO Algorithm". Energies 12, nr 21 (28.10.2019): 4115. http://dx.doi.org/10.3390/en12214115.
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Distributed, generation-based micro-grids are increasingly being used in the build-up of the modern power system. However, the protection of these micro-grids has many challenges. One of the important challenges is the coordination of directional overcurrent (DOC) relays. The optimization of the coordination of DOC relays is considered a nonlinear programming problem with pre-defined constrains. In this paper, the problem of the optimal coordination of DOC relays is solved using a multi-verse optimization (MVO) algorithm which is inspired from cosmology science. The proposed algorithm is tested by applying it to Institute of Electrical and Electronics Engineers (IEEE) 3 bus and IEEE 9 bus networks. The performance of the proposed algorithm is compared with the particle swarm optimization (PSO) algorithm when applied to both networks. All results show that the performance of the MVO algorithm is better than PSO in terms of its reduction of both the overall operating time (OT) of DOC relays and the computational burden of the computer solving the optimization problem.
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Haarhoff, J., M. Kubare, B. Mamba, R. Krause, T. Nkambule, B. Matsebula i J. Menge. "NOM characterization and removal at six Southern African water treatment plants". Drinking Water Engineering and Science 3, nr 1 (15.04.2010): 53–61. http://dx.doi.org/10.5194/dwes-3-53-2010.
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Abstract. Organic pollution is a major concern during drinking water treatment. Major challenges attributed to organic pollution include the proliferation of pathogenic micro-organisms, prevalence of toxic and physiologically disruptive organic micro-pollutants, and quality deterioration in water distribution systems. A major component of organic pollution is natural organic matter (NOM). The operational mechanisms of most unit processes are well understood. However, their interaction with NOM is still the subject of scientific research. This paper takes the form of a meta-study to capture some of the experiences with NOM monitoring and analysis at a number of Southern African Water Treatment Plants. It is written from the perspective of practical process selection, to try and coax some pointers from the available data for the design of more detailed pilot work. NOM was tracked at six water treatment plants using dissolved organic carbon (DOC) measurements. Fractionation of the DOC based on biodegradability and molecular weight distribution was done at a water treatment plant in Namibia. A third fractionation technique using ion exchange resins was used to assess the impact of ozonation on DOC. DOC measurements alone did not give much insight into NOM evolution through the treatment train. The more detailed characterization techniques showed that different unit processes preferentially remove different NOM fractions. Therefore these techniques provide better information for process design and optimisation than the DOC measurement which is routinely done during full scale operation at these water treatment plants.
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Wang, Tao, Xiaoyu Wu, Guoqing Zhang, Bin Xu, Yinghua Chen i Shuangchen Ruan. "Experimental Study on Machinability of Zr-Based Bulk Metallic Glass during Micro Milling". Micromachines 11, nr 1 (13.01.2020): 86. http://dx.doi.org/10.3390/mi11010086.
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The micro machinability of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass (BMG) was investigated by micro milling with coated cemented carbide tools. The corresponding micro milling tests on Al6061 were conducted for comparison. The results showed that the tool was still in stable wear stage after milling 300 mm, and the surface roughness Ra could be maintained around 0.06 μm. The tool experienced only slight chipping and rubbing wear after milling the BMG, while a built-up edge and the coating peeling off occurred severely when milling Al6061. The influence of rotation speed on surface roughness was insignificant, while surface roughness decreased with the reduction of feed rate, and then increased dramatically when the feed rate was below 2 μm/tooth. The surface roughness increased gradually with the axial depth of cut (DOC). Milling force decreased slightly with the increase in rotation speed, while it increased with the increase in axial DOC, and the size effect on milling force occurred when the feed rate decreased below 1 μm/tooth. The results of X-ray diffraction (XRD) showed that all milled surfaces were still dominated by an amorphous structure. This study could pave a solid foundation for structural and functional applications.
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Ernst, M., i M. Jekel. "Advanced Treatment Combination for Groundwater Recharge of Municipal Wastewater by Nanofiltration and Ozonation". Water Science and Technology 40, nr 4-5 (1.08.1999): 277–84. http://dx.doi.org/10.2166/wst.1999.0601.
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This paper presents the results of research undertaken on an advanced treatment combination for polishing municipal wastewater with the purpose of a safe groundwater recharge. The results of a former study of DWQC initiated this research. It is envisaged that tertiary effluent is nanofiltrated to reject dissolved organic carbon (DOC) and adsorbable organic halogens (AOX) to concentrations less than 2–3 mg DOC/L respectively <2 μg AOX/L. The brine will be given back in a recycling process to the sewage treatment plant after passing an oxidation step. To avoid rising scaling potentials and other negative impacts due to increasing salinity, the rejection characteristics of several NF-membranes were investigated. They show a strong dependence between DOC and sulfate removal. Biofouling on the membrane surface (Desal DK5) can be controlled by higher cross-flow velocities (CFV) of about 1 m/s, however, a suitable pre-treatment like slow sand filtration is required. High water conversion factors result in moderately higher biofouling. This shows that water quality is the main factor responsible for fouling and not the concentration of constituents. Ozonation experiments with the concentrate confirmed an enhanced biodegradability of refractory DOC. At a specific ozone consumption 1,7 mg O3/mg DOC0 the DOC reduction by micro-organisms (aerobic biotest) reaches its maximum after 14 days of biodegradation with a total reduction of 60%.
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Buyong, Muhamad Ramdzan, Farhad Larki, Muhamad Ikhmal Hakimi Zainal, Abdelaziz Yousif Ahmed Almahi, Ahmad Ghadafi Ismail, Azrul Azlan Hamzah, Aminuddin Ahmad Kayani Kayani, Céline Elie Caille i Burhanuddin Yeop Majlis. "Implementation of capacitance as simultaneous sensing and actuating tool in tapered microelectrode arrays for dielectrophoresis-on-a-chip application". Microelectronics International 37, nr 4 (21.09.2020): 215–24. http://dx.doi.org/10.1108/mi-04-2020-0023.
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Purpose This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation. Design/methodology/approach The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles. Findings The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation. Originality/value The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.
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Liu, Qi Feng. "Research on Treatment of the Micro-Polluted Reservoir Water with Ozone Oxidation". Advanced Materials Research 884-885 (styczeń 2014): 129–33. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.129.
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Bench and pilot scale pre-oxidation treatment runs were performed on the raw water samples from micro-polluted reservoir. Bench experimental results showed that the particles with large size decreased when ozone pre-oxidation was applied, meanwhile, the organic matters with unsaturated chemical bonds decreased obviously. Pilot experimental results showed that turbidity, UV254,CODMn and total coliform could be treated efficiently by ozone pre-oxidation combined with traditional technologies, but the effectiveness of DOC removal is not obvious. Keywords: ozone oxidation; UV254; Organic matter; micro-polluted water
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Graveland, A. "Particle and micro-organism removal in conventional and advanced treatment technology". Water Science and Technology 37, nr 10 (1.05.1998): 125–34. http://dx.doi.org/10.2166/wst.1998.0392.
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All international drinking water quality standards can be divided into four groups – (micro)biological: bacteria, viruses, cysts, higher organisms, etc. – toxicological: THM, AOX, pesticides, solvents, etc. – organoleptic (esthetic): taste, odor, color, turbidity, etc. – operational: DOC, AOC, pH, Ca2+, HCO3−, Cl−, SO42−, etc. The philosophy on drinking water treatment focuses on the removal of all the undesired species, dissolved and undissolved, available in raw water, in such a way that no new undesired compounds are introduced during treatment such as Al, Cl2, THM, AOX and AOC or during distribution such as Pb, Cu, Cd and asbestos. Special attention is paid to the removal of organic and inorganic colloids and of micro-organisms. Microbiologically stable water during storage and distribution can be realized by removal of nutrients (DOC, AOC) without the use of chlorine of chlorine products. As an example the treatment systems of the Amsterdam Water Supply based on the relatively very polluted raw water of the river Rhine are described. For future expansion of the production capacity membrane processes such as hyperfiltration (HF), electrodialysis reversal (EDR) and ultrafiltration (UF) are investigated. Results are shown on conventional and advanced technology concerning: final water quality, natural and environmental protection, process stability and costs per m3.
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Luppi, Andrea I., Joshua Cain, Lennart R. B. Spindler, Urszula J. Górska, Daniel Toker, Andrew E. Hudson, Emery N. Brown i in. "Mechanisms Underlying Disorders of Consciousness: Bridging Gaps to Move Toward an Integrated Translational Science". Neurocritical Care 35, S1 (lipiec 2021): 37–54. http://dx.doi.org/10.1007/s12028-021-01281-6.
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Abstract Aim In order to successfully detect, classify, prognosticate, and develop targeted therapies for patients with disorders of consciousness (DOC), it is crucial to improve our mechanistic understanding of how severe brain injuries result in these disorders. Methods To address this need, the Curing Coma Campaign convened a Mechanisms Sub-Group of the Coma Science Work Group (CSWG), aiming to identify the most pressing knowledge gaps and the most promising approaches to bridge them. Results We identified a key conceptual gap in the need to differentiate the neural mechanisms of consciousness per se, from those underpinning connectedness to the environment and behavioral responsiveness. Further, we characterised three fundamental gaps in DOC research: (1) a lack of mechanistic integration between structural brain damage and abnormal brain function in DOC; (2) a lack of translational bridges between micro- and macro-scale neural phenomena; and (3) an incomplete exploration of possible synergies between data-driven and theory-driven approaches. Conclusion In this white paper, we discuss research priorities that would enable us to begin to close these knowledge gaps. We propose that a fundamental step towards this goal will be to combine translational, multi-scale, and multimodal data, with new biomarkers, theory-driven approaches, and computational models, to produce an integrated account of neural mechanisms in DOC. Importantly, we envision that reciprocal interaction between domains will establish a “virtuous cycle,” leading towards a critical vantage point of integrated knowledge that will enable the advancement of the scientific understanding of DOC and consequently, an improvement of clinical practice.
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Haarhoff, J., M. Kubare, B. Mamba, R. Krause, T. Nkambule, B. Matsebula i J. Menge. "NOM characterization and removal at six Southern African water treatment plants". Drinking Water Engineering and Science Discussions 2, nr 2 (10.11.2009): 231–57. http://dx.doi.org/10.5194/dwesd-2-231-2009.
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Abstract. Organic pollution is a major concern during drinking water treatment. Major challenges attributed to organic pollution include the proliferation of pathogenic micro-organisms, prevalence of toxic and physiologically disruptive organic micropollutants, and quality deterioration in water distribution systems. A major component of organic pollution is natural organic matter (NOM). The operational mechanisms of most unit processes are well understood. However, their interaction with NOM is still the subject of scientific research. This paper takes the form of a metastudy to capture some of the experiences with NOM monitoring and analysis at a number of Southern African Water Treatment Plants. It is written from the perspective of practical process selection, to try and coax some pointers from the available data for the design of more detailed pilot work. NOM was tracked at six water treatment plants using dissolved organic carbon (DOC) measurements. Fractionation of the DOC based on biodegradability and molecular weight distribution was done at a water treatment plant in Namibia. A third fractionation technique using ion exchange resins was used to assess the impact of ozonation on DOC. DOC measurements alone did not give much insight into NOM evolution through the treatment train. The more detailed characterization techniques showed that different unit processes preferentially remove different NOM fractions. Therefore these techniques provide better information for process design and optimisation than the DOC measurement which is routinely done during full scale operation at these water treatment plants. Further work will focus on streamlining and improving the reproducibility of selected fractionation techniques, characterization of NOM from different water sources, and synthesis of the results into a systematic, practical guideline for process design and optimisation.
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Al-Zain, Afnan O., Ziyad A. Al-Ghamdi, Mahfouz M. Basahal, Rozana M. Al-Bukhary i EliseuAldrighi Münchow. "Performance of Multiple Light-curing Units used by Dental Students". Open Dentistry Journal 14, nr 1 (31.12.2020): 671–80. http://dx.doi.org/10.2174/1874210602014010671.
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Aim: To investigate the performance of multiple Light-curing Units (LCUs) of different manufacturers used in a dental student clinical setting. Background: Manufacturers claim that the irradiance values of the LCUs stay stable over time. However, this may not be accurate among the different units. Objective: This study investigated the performance in terms of the irradiance, radiant exposure, and DOC of multiple LCUs of different types used in a dental student clinical setting. Methods: Four different LCU were investigated (n=5 units/LCU manufacturer): three Light-Emitting-Diodes (LED) units (Demi Ultra, Mini LED, and E-Morlit) and one quartz-tungsten-halogen (QTH) (PolyluxII). Irradiance and radiant exposure were collected [Managing Accurate Resin Curing-Patient Simulator (MARC-PS)](n=5 readings/unit/tooth). Depth of Cure (DOC) was performed (ISO 4049:2009standards) using a micro-hybrid composite (n=5/unit). Data were analyzed using Kruskal-Wallis and ANOVA followed by Student-Newman-Keuls and Tukey post hoc methods, respectively (α=0.05). Results: Using the MARC-PS anterior and posterior teeth sensors, respectively, the mean irradiance for Demi Ultra was (1625.7±38.8) and (1250.4±25.2); Mini LED (1381.1±37.8) and (1058.1±27.3); E-Morlit (1831.1±294.7) and (1545.2±176.0); and Polylux II (932.4±368.5) and (840.4±353.4)mW/cm2. The radiant exposure range was 16-38 J/cm2 for all LCUs. LCUs’ mean DOC ranged from 2.9 to 3.1 mm. Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers. Significant differences in DOC values among the Demi Ultra and Polylux II units were detected. DOC met the standards except for onePolylux II unit. Conclusion: The irradiance and radiant exposure values were not the same among the different units, regardless of the manufacturers’ claim of the irradiance values stability over time. Polymerization was not compromised except for one QTH unit per the DOC measurements. Itis highly recommended to closely monitor LCUs used in dental student clinical areas due to the high demand in this type of setting.
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Yamashita, T., R. Yamamoto-Ikemoto i E. Sakurai. "Treatment of dye works wastewater using anaerobic–oxic biological filter reactor packed with carbon fibre and aerated with micro-bubbles". Water Science and Technology 53, nr 11 (1.05.2006): 151–61. http://dx.doi.org/10.2166/wst.2006.348.
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A new anaerobic–oxic biological filter reactor, which was packed with carbon fibre and aerated with micro-bubbles, was proposed. The reactor performance was examined using dye works wastewater compared with the activated sludge reactor. Effluent SS from the experimental reactor was significantly lower than that from the activated sludge reactor, and transparency was higher. Temperatures of the activated sludge reactor were over 35 °C and DOC removal ratios were 40–80% depending on the influent wastewater. On the other hand, the DOC removal efficiency of the experimental reactor was over 70%, when the reactor temperature was over 22 °C. In the anaerobic zone, sulphate reduction occurred predominantly and acetate was produced. In the oxic reactor, sulphur oxidation and organic removal occurred. When the amount of sulphate reduction in the anaerobic zone increased, DOC and colour in effluent decreased. The sulphate reducing activity of biofilm at 30 °C was three times higher than those at 20 °C. The sulphate reducing activity of biofilm in the oxic zone was higher than those in the anaerobic zone, meaning that the sulphate reduction-oxidation cycles were established in the biofilm of the oxic zone. Microbial community of sulphate reducing bacteria was examined by in situ hybridisation with 16S rRNA targeted oligonucleotide probes. Desulfobulbus spp. was most common sulphate reducing bacteria in the anaerobic zone. In the oxic zone, Desulfobulbus spp. and Desulfococcus spp. were observed.
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Gao, Yunpei, Yizhe Gong i Xiaoyan Chen. "Constraining the Ediacaran oceanic dissolved organic carbon reservoir: Insights from carbon isotopic records from a drill core from South China". JUSTC 52, nr 2 (2022): 5. http://dx.doi.org/10.52396/justc-2021-0226.
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The evolution of the atmospheric oxygen content through Earth’s history is a key issue in paleoclimatic and paleoenvironmental research. There were at least two oxygenation events in the Precambrian that involved fundamental changes in both biotic innovation and the surface environment. However, a large dissolved organic carbon (DOC) pool maintained in deep oceans during the Neoproterozoic may have extended the time interval between the two oxygenation events. To test the DOC hypothesis, we conducted detailed micro-drilled analyses of carbonate carbon isotopes (δ<sup>13</sup>C<sub>carb</sub>) of a long Ediacaran drill core (the Wangji drill core), for which whole-rock δ<sup>13</sup>C<sub>carb</sub> and organic carbon isotope (δ<sup>13</sup>C<sub>org</sub>) records were available. The micro-drilled δ<sup>13</sup>C<sub>carb </sub>values obtained in this stdudy are consistent with whole-rock δ<sup>13</sup>C<sub>carb</sub> results, precluding the influence of severe authigenic carbonate incorporation. Importantly, the multiple negative δ<sup>13</sup>C<sub>carb</sub> excursions in the Wangji drill core were likely linked with upwelling events, during which DOC was supplied to the surface water and oxidized. Using box models, we estimate that ~3.6 × 10<sup>19</sup> mol and ~2.0 × 10<sup>19</sup> mol DOC were converted to bicarbonate during two negative δ<sup>13</sup>C<sub>carb</sub> excursions spanning millions of years. The estimations are approximately 1000 times the modern marine DOC reservoir. Our results support a relatively high oxidation capacity (elevated atmospheric <i>p</i>O<sub>2</sub> and/or oceanic [<inline-formula><tex-math id="Z-20220120101958">\begin{document}${\rm{SO}}_4^{2 - }$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="JUST-2021-0226_Z-20220120101958.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="JUST-2021-0226_Z-20220120101958.png"/></alternatives></inline-formula>]) of the Earth’s surface during the early Ediacaran Period.
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Ilie, N., i BI Luca. "Efficacy of Modern Light Curing Units in Polymerizing Peripheral Zones in Simulated Large Bulk-fill Resin-composite Fillings". Operative Dentistry 43, nr 4 (1.07.2018): 416–25. http://dx.doi.org/10.2341/17-095-l.
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SUMMARY The variation in micro-hardness (HV) within simulated large cavities (10 × 6 mm) filled in one increment with three bulk-fill resin-based composites (BF-RBC) was assessed by means of a universal hardness device. Modern blue and violet-blue light curing units (LCUs) were applied in three different positions, by rotating the LCU in 120° steps. The exposure distance was 3 mm. One center and two peripheral (4-mm apart from the center) HV line profiles were measured in 0.5-mm steps at 24 hours postpolymerization to calculate the depth of cure (DOC). Incident light, irradiance, and spectral distribution were recorded. A multivariate analysis (general linear model) assessed the effect of the varied parameters as well as their interaction terms on HV and DOC. The effect of LCU rotation was not significant (p=0.109). The DOC varied between 3.46 mm and 5.50 mm and was more strongly influenced by the BF-RBC (p<0.001, ηP2=0.774), followed by the width of specimen (p<0.001, ηP2=0.554), while the influence of the LCU was very low (p<0.06, ηP2=0.070). Whether a BF-RBC filling is cured as well in the periphery as in the center depends more on the material than on the curing unit used.
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Raudina, Tatiana V., Sergey V. Loiko, Artyom G. Lim, Ivan V. Krickov, Liudmila S. Shirokova, Georgy I. Istigechev, Daria M. Kuzmina, Sergey P. Kulizhsky, Sergey N. Vorobyev i Oleg S. Pokrovsky. "Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia". Biogeosciences 14, nr 14 (27.07.2017): 3561–84. http://dx.doi.org/10.5194/bg-14-3561-2017.
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Abstract. Mobilization of dissolved organic carbon (DOC) and related trace elements (TEs) from the frozen peat to surface waters in the permafrost zone is expected to enhance under ongoing permafrost thaw and active layer thickness (ALT) deepening in high-latitude regions. The interstitial soil solutions are efficient tracers of ongoing bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of the sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, dissolved inorganic carbon (DIC), and 40 major elements and TEs in 0.45 µm filtered fraction of 80 soil porewaters. Despite an expected decrease in the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase in the permafrost coverage and a decrease in the annual temperature and ALT, the DOC and many major and trace elements did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2 to 67.4° N. The DOC demonstrated a maximum of concentration at 66° N, on the border of the discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from the continuous permafrost zone was equal to or higher than that in the sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, rare earth elements (REEs), Zr, Hf, Th) elements exhibited an increasing, not decreasing, northward concentration trend. We hypothesize that the effects of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat, which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REEs, and Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat porewater enrichments in DOC and other solutes. A 2° northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 ± 0.2 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th, and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, specific ultraviolet absorbency (SUVA), Ca, Mg, Fe, and Sr will not exceed 20 % of their current values. The projected increase in ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime is unlikely to modify chemical composition of peat porewater fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2. The decrease in DOC and metal delivery to small rivers and lakes by peat soil leachate may also decrease the overall export of dissolved components from the continuous permafrost zone to the Arctic Ocean. This challenges the current paradigm on the increase in DOC export from the land to the ocean under climate warming in high latitudes.
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Elshazly, Tarek M., Christoph Bourauel, Dalia I. Sherief i Dalia I. El-Korashy. "Evaluation of Two Resin Composites Having Different Matrix Compositions". Dentistry Journal 8, nr 3 (17.07.2020): 76. http://dx.doi.org/10.3390/dj8030076.
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This study compared two resin composites with similar filler systems and different matrix compositions. The depth of cure (DoC), polymerization shrinkage, and marginal leakage were evaluated. A Filtek Bulk Fill resin composite (FB) and a Filtek Supreme resin composite (FS) were used. For the DoC and polymerization shrinkage, cylindrical specimens with different thicknesses were prepared. The DoC was attributed to the bottom/top ratios of Vickers microhardness numbers. For polymerization shrinkage, each specimen was firstly scanned using micro-computed tomography (µCT) then cured for 20 s, then for 10 s, and then for 10 s, and they were rescanned between each curing time. Data were processed using the Mimics software. For marginal leakage, standardized 5 mm cavities were prepared in 90 molars. After etching and bonding, materials were packed according to groups: FB-bulk, FB-incremental, and FS-incremental, which were cured for 20, 30, and 40 s, respectively. After thermo-cycling, teeth were stored in 1% methylene blue dye for 24 h and then sectioned and observed for dye penetration. The results showed insignificant differences in the shrinkage and leakage between the different packing techniques and curing times of both materials. In conclusion, the introduction of a novel matrix into resin composite composition enabled bulk-filling in one layer up to 5 mm deep while keeping a tolerable polymerization shrinkage.
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Greenwood, J., J. Adu, A. J. Davey, N. J. Abbott i M. W. B. Bradbury. "The Effect of Bile Salts on the Permeability and Ultrastructure of the Perfused, Energy-Depleted, Rat Blood-Brain Barrier". Journal of Cerebral Blood Flow & Metabolism 11, nr 4 (lipiec 1991): 644–54. http://dx.doi.org/10.1038/jcbfm.1991.116.
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The action of bile salts upon the rat blood–brain barrier (BBB) was assessed in the absence of energy-yielding metabolism. Brains were perfused in situ with a Ringer solution for 5 min followed by a 1 min perfusion containing either sodium deoxycholate (DOC), taurochenodeoxycholate (TCDC), or Ringer/DNP. The integrity of the BBB was then determined by perfusing with the radiotracer [14C]mannitol for 2.5 min. Alternatively, the brains were perfusion fixed for ultrastructural assessment. At 0.2 m M DOC, the BBB remained intact and the cerebral ultrastructure was similar to the controls. At 1 m M and above, disruption of the BBB became evident. At 2 m M, the cerebral cortex became severely vacuolated, with damaged endothelium and collapsed capillaries. With TCDC, BBB disruption occurred at 0.2 m M without any apparent ultrastructural damage to the micro vasculature. Following 2 m M TCDC, similar, but less widespread, structural changes to the 2 m M DOC-perfused animals was apparent. Opening of the BBB occurred at a concentration lower than that required to cause lysis of either red blood cells or cultured cerebral endothelial cells. It is proposed that the effect of bile salts at concentrations of 1.5 m M and above is largely due to their lytic action as strong detergents on endothelial cell membranes, but that at lower concentrations a more subtle modification of the BBB occurs.
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Kurihara, Haruko, Nao Ikeda i Yu Umezawa. "Diurnal and seasonal variation of particle and dissolved organic matter release by the coral Acropora tenuis". PeerJ 6 (7.11.2018): e5728. http://dx.doi.org/10.7717/peerj.5728.
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Release rates of particulate organic carbon and nitrogen (POC and PON) and dissolved organic carbon (DOC) from the scleractinian coral Acropora tenuis were measured during the day and night in summer and winter seasons. Physiological parameters including calcification, photosynthesis and respiration rates were also measured simultaneously. The release rate of both POC and DOC was significantly higher in summer compared to winter and higher during the day compared to the night. The daily release rate of total organic carbon (POC + DOC) was 1,094 and 219 μmol C cm−2 d−1 for summer and winter, respectively, being 4.9 times higher in summer. The POC:PON ratios of the particulate organic matter released during daytime in both seasons (summer: 12.8 ± 5.7, winter: 12.0 ± 4.1) were significantly higher than those during nighttime (summer: 6.1 ± 2.5, winter: 2.2 ± 1.8). The DOC:POC ratio was 0.5 ± 0.03 during summer and 0.32 ± 0.98 during winter, suggesting higher mucus release in particulate form. Daily net production was estimated to be 199 and 158 μg C cm−2d−1 for summer and winter, respectively, with the amount of carbon released as mucus accounting for 6.5% and 1.6% of the net carbon fixation, respectively. The study reveals diurnal and seasonal changes in the quantity and quality of mucus released from this coral species. Since coral mucus is used as a food source by reef macro-organisms, and can also serve as an energy source for micro-organisms, the observed changes in mucus release rates are expected to influence the seasonal dynamics of organic carbon and nitrogen cycling over coral reefs.
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Minegishi, S., N. Y. Jang, Y. Watanabe, S. Hirata i G. Ozawa. "Fouling mechanism of hollow fiber ultrafiltration membrane with pretreatment by coagulation/sedimentation process". Water Supply 1, nr 4 (1.06.2001): 49–56. http://dx.doi.org/10.2166/ws.2001.0066.
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The fouling mechanism of the hollow fiber UF membrane with a pretreatment by coagulation/sedimentation process was investigated. The experiments were carried out in three different feed water conditions: river surface water, coagulated water containing micro flocs and clarified water from the coagulation/sedimentation process. The river water contained a lot of suspended particles (high turbidity) and natural organic matter (NOM) such as humic substances. From analysis of the data obtained in the three membrane processes, the mathematical model expressing the change of the filtration resistance is proposed and proved, which includes the pore size distribution of the membrane. The effect of DOC and DOC/E260 on the membrane fouling was also discussed. The analysis of the pore size distribution change with increasing filtration time suggests that the primary mechanism of the fouling is the decrease in the pore number by the high molecular weight humic substances. As a result of experiments and mathematical model analysis, it could be concluded that the coagulation/sedimentation pretreatment process was very effective for expanding ultrafiltration membrane life, because the coagulation/sedimentation process could remove the primary foulants such as high molecular weight humic substances.
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Pradhan, Subhadip, Sourav Sanket Tripathy, Sushreesudha Sahu, Sudhansu Ranjan Das, Pankaj Charan Jena i Debabrata Dhupal. "Investigation on MRR and DOC of the micro-holes generated on quartz using silicon carbide by FB-HAJM". Materials Today: Proceedings 26 (2020): 2005–12. http://dx.doi.org/10.1016/j.matpr.2020.02.437.
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Zhou, Hua, Wan Tai Yu i Qiang Ma. "Seasonal Changes in Various Soil Organic Carbon Pools with Different Soil Amendments". Advanced Materials Research 599 (listopad 2012): 870–74. http://dx.doi.org/10.4028/www.scientific.net/amr.599.870.
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In a sustainable agriculture farming systems experiment, the dynamics of soil organic carbon (OC), carbon/nitrogen (C/N) ratio and labile organic carbon pool in soil amended with maize stalk (MS), rice straw (RS) and alfalfa (AF) were studied from August 2005 to August 2006. The results showed that organic material with low N content decomposed slowly, while that with absolutely high N content depressed decomposition rate. After one year’s decomposition, the humification process of organic materials was basically complete. Soil labile carbon content was dramatically improved compared with the control after the addition of organic materials to the soil. The leached DOC was highly correlated with micro-organisms activity and MBC was highly dependent on N incorporation.
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Koch, B. P., G. Kattner, M. Witt i U. Passow. "Molecular insights into the microbial formation of marine dissolved organic matter: recalcitrant or labile?" Biogeosciences Discussions 11, nr 2 (25.02.2014): 3065–111. http://dx.doi.org/10.5194/bgd-11-3065-2014.
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Abstract. The degradation of marine dissolved organic matter (DOM) is an important control variable in the global carbon cycle and dependent on the DOM composition. For our understanding of the kinetics of organic matter cycling in the ocean, it is therefore crucial to achieve a mechanistic and molecular understanding of its transformation processes. A long-term microbial experiment was performed to follow the production of non-labile DOM by marine bacteria. Two different glucose concentrations and dissolved algal exudates were used as substrates. We monitored the bacterial abundance, concentrations of dissolved and particulate organic carbon (DOC, POC), nutrients, amino acids, and transparent exopolymer particles (TEP) for two years. Ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) allowed the molecular characterization of extracted DOM after 70 days and after ∼2 years of incubation. Although glucose was quickly degraded, a DOC background was generated in glucose incubations. Only 20% of the organic carbon from algal exudate was degraded within the 2 years of incubation. TEP, which are released by micro-organisms, were produced during glucose degradation but decreased within less than three weeks back to half of the maximum concentration and were below detection in all treatments after 2 years. The molecular analysis demonstrated that DOM generated during glucose degradation differed appreciably from DOM produced during the degradation of the algal exudates. Our results led to several conclusions: (i) Higher substrate levels result in a higher level of non-labile DOC which is an important prerequisite for carbon sequestration in the ocean; (ii) TEP are generated by bacteria but are also degraded rapidly, thus limiting their potential contribution to carbon sequestration; (iii) The molecular signatures of DOM derived from algal exudates or glucose after 70 days of incubation differed strongly from refractory DOM. After 2 years, however, the molecular patterns of DOM in glucose incubations were more similar to deep ocean DOM whereas the degraded exudate was still different.
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Nkambule, T. I., R. W. M. Krause, J. Haarhoff i B. B. Mamba. "The characterisation of natural organic matter (NOM) in South African waters". Water Supply 12, nr 5 (1.08.2012): 648–57. http://dx.doi.org/10.2166/ws.2012.038.
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The removal of natural organic matter (NOM) from water is becoming increasingly important in order to prevent the formation of carcinogenic disinfection by-products (DBPs). The inadequate removal of NOM has a bearing on the capacity of other treatment processes to remove organic micro-pollutants or inorganic species that may be present in water. In order to effectively study the nature of South African water sources in terms of their NOM composition, water samples were collected from drinking water treatment plants in the five geographic water regions of South Africa. A raw water sample, an intermediate sample taken before sand filtration and a final sample after sand filtration were collected three times from these water treatment plants at two-month intervals and over three different seasons. Fluorescence excitation-emission matrices (FEEM), biodegradable dissolved organic carbon (BDOC), ultraviolet (UV) characterisation (200–900 nm) and dissolved organic carbon (DOC) analyses were used to characterise the NOM in the water samples. The FEEM and UV results revealed that the samples were composed mainly of non-humic substances with low UV-254 absorbance, while some samples had high humic substances with high UV-254 values. The samples' DOC results were within the range of 3.25–21.44 mg/L carbon, which was indicative of the varying nature of the NOM composition in the regions where samples were collected. The BDOC fraction of the NOM, on the other hand, ranged from 20 to 65%, depending on the geographical location of the sampling site.
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Kolář, L., F. Klimeš, J. Gergel, S. Kužel, M. Kobes, R. Ledvina i M. Šindelářová. "Methods to evaluate substrate degradability in anaerobic digestion and biogas production". Plant, Soil and Environment 51, No. 4 (19.11.2011): 173–78. http://dx.doi.org/10.17221/3571-pse.
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Two methods developed by Prof. Dohányos and Doc. Zábranská from ICT in Prague (A) and Oxi Top Control AN 12 measuring system manufactured by MERCK Company (B), were used to determine the maximum yield of biogas and methane and the maximum rate of biogas and methane production per unit weight of biomass using buffered and macro- and micro-nutrient enriched grass biomass as a substrate. Statistical evaluation proved that the Oxi Top Control method did not provide significantly lower or higher results than the other method that is considered standard. Although the Oxi Top Control AN 12 method has a higher variance of measured values than the standard method, it can be recommended as a project and operation method for its work comfort and expeditiousness.
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Pirkwieser, Philip, José López-López, Wolfgang Kandioller, Bernhard Keppler, Carlos Moreno i Franz Jirsa. "Solvent Bar Micro-Extraction of Heavy Metals from Natural Water Samples Using 3-Hydroxy-2-Naphthoate-Based Ionic Liquids". Molecules 23, nr 11 (17.11.2018): 3011. http://dx.doi.org/10.3390/molecules23113011.
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Developments in the liquid micro-extraction of trace metals from aqueous phases have proven to be limited when extended from pure water to more complex and demanding matrices such as sea water or wastewater treatment effluents. To establish a system that works under such matrices, we successfully tested three task-specific ionic liquids, namely trihexyltetradecyl- phosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoate in two-phase solvent bar micro-extraction (SBME) experiments. We describe the influence of pH, organic additives, time, stirring rate and volume of ionic liquid for multi-elemental micro-extraction of Cu, Ag, Cd and Pb from various synthetic and natural aqueous feed solutions. Highest extraction for all metals was achieved at pH 8.0. Minimal leaching of the ionic liquids into the aqueous phase was demonstrated, with values < 30 mg L−1 DOC in all cases. Sample salinities of up to 60 g L−1 NaCl had a positive effect on the extraction of Cd, possibly due to an efficient extraction mechanism of the present chlorido complexes. In metal-spiked natural feed solutions, the selected SBME setups showed unchanged stability under all conditions tested. We could efficiently (≥85%) extract Cu and Ag from drinking water and achieved high efficacies for Ag and Cd from natural sea water and hypersaline water, respectively. The method presented here proves to be a useful tool for an efficient SBME of heavy metals from natural waters without the need to pretreat or modify the sample.
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Pokrovsky, Oleg S., Rinat M. Manasypov, Sergey G. Kopysov, Ivan V. Krickov, Liudmila S. Shirokova, Sergey V. Loiko, Artem G. Lim, Larisa G. Kolesnichenko, Sergey N. Vorobyev i Sergey N. Kirpotin. "Impact of Permafrost Thaw and Climate Warming on Riverine Export Fluxes of Carbon, Nutrients and Metals in Western Siberia". Water 12, nr 6 (24.06.2020): 1817. http://dx.doi.org/10.3390/w12061817.
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The assessment of riverine fluxes of carbon, nutrients, and metals in surface waters of permafrost-affected regions is crucially important for constraining adequate models of ecosystem functioning under various climate change scenarios. In this regard, the largest permafrost peatland territory on the Earth, the Western Siberian Lowland (WSL) presents a unique opportunity of studying possible future changes in biogeochemical cycles because it lies within a south–north gradient of climate, vegetation, and permafrost that ranges from the permafrost-free boreal to the Arctic tundra with continuous permafrost at otherwise similar relief and bedrocks. By applying a “substituting space for time” scenario, the WSL south-north gradient may serve as a model for future changes due to permafrost boundary shift and climate warming. Here we measured export fluxes (yields) of dissolved organic carbon (DOC), major cations, macro- and micro- nutrients, and trace elements in 32 rivers, draining the WSL across a latitudinal transect from the permafrost-free to the continuous permafrost zone. We aimed at quantifying the impact of climate warming (water temperature rise and permafrost boundary shift) on DOC, nutrient and metal in rivers using a “substituting space for time” approach. We demonstrate that, contrary to common expectations, the climate warming and permafrost thaw in the WSL will likely decrease the riverine export of organic C and many elements. Based on the latitudinal pattern of riverine export, in the case of a northward shift in the permafrost zones, the DOC, P, N, Si, Fe, divalent heavy metals, trivalent and tetravalent hydrolysates are likely to decrease the yields by a factor of 2–5. The DIC, Ca, SO4, Sr, Ba, Mo, and U are likely to increase their yields by a factor of 2–3. Moreover, B, Li, K, Rb, Cs, N-NO3, Mg, Zn, As, Sb, Rb, and Cs may be weakly affected by the permafrost boundary migration (change of yield by a factor of 1.5 to 2.0). We conclude that modeling of C and element cycle in the Arctic and subarctic should be region-specific and that neglecting huge areas of permafrost peatlands might produce sizeable bias in our predictions of climate change impact.
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Mehling, Simon, Tobias Schnabel i Jörg Londong. "Photocatalytic ozonation in an immersion rotary body reactor for the removal of micro-pollutants from the effluent of wastewater treatment plants". Water Science and Technology 85, nr 1 (10.12.2021): 535–48. http://dx.doi.org/10.2166/wst.2021.617.
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Abstract Carrier-bound titanium dioxide catalysts were used in a photocatalytic ozonation reactor for the degradation of micro-pollutants in real wastewater. A photocatalytic immersion rotary body reactor with a 36-cm disk diameter was used, and was irradiated using UV-A light-emitting diodes. The rotating disks were covered with catalysts based on stainless steel grids coated with titanium dioxide. The dosing of ozone was carried out through the liquid phase via an external enrichment and a supply system transverse to the flow direction. The influence of irradiation power and ozone dose on the degradation rate for photocatalytic ozonation was investigated. In addition, the performance of the individual processes photocatalysis and ozonation were studied. The degradation kinetics of the parent compounds were determined using liquid chromatography tandem mass spectrometry. First-order kinetics were determined for photocatalysis and photocatalytic ozonation. A maximum reaction rate of the reactor was determined, which could be achieved by both photocatalysis and photocatalytic ozonation. At a dosage of 0.4 mg /mg DOC, the maximum reaction rate could be achieved using 75% of the irradiation power used for sole photocatalysis, allowing increases in the energetic efficiency of photocatalytic wastewater treatment processes. The process of photocatalytic ozonation is suitable to remove a wide spectrum of micro-pollutants from wastewater.
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Lee, Byoung-Ho, Won-Chul Song, Hyun-Joo Yang, Jeong-Hyun Kim i Young-Suk Kim. "Oxidation efficiencies of natural organic matter by the different ozone contact systems". Water Supply 8, nr 6 (1.12.2008): 673–80. http://dx.doi.org/10.2166/ws.2008.152.
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Owing to the strong oxidation potential, ozone has been used widely in advanced water treatment. However, degradation and oxidation efficiencies of NOM (Natural Organic Matter) by the traditional ozone contact system are normally believed to be low. Oxidation efficiency of NOM by the PHOC (Pressurized High Ozone Contact) method was compared with that by the MOC (Mechanical Ozone Contact, the traditional system) method for the drinking water treatment. Sand filtered water of the drinking water treatment plant was used for experimental samples. Removal rates of UV254 absorbance, KMnO4 consumption and DOC by the MOC system were 18.4%, 2.39%, and 2.72% respectively with 1 mg-O3/L. On the other hand, removal rates of KMnO4 consumption, TOC, DOC, UV254 absorbance and SUVA by the PHOC system were 8–20%, 7.52–34.4%, 6.65–18.2%, 37.4–60.8% and 33.8–60% with 1–3 mg/L of ozone concentrations. Concentration of BDOC after ozone application was 0.003–0.044 mg/L by the MOC method, while 0.084–0.044 mg/L by the PHOC method with 1–3 mg/L of ozone concentrations. Concerning molecular weight distribution, fractions of NOM below 1 kDa were increased by the PHOC method of ozone application. Analysis shows that the reason for overall enhancement of the treatment efficiencies by the PHOC system is because contacting surface area of numerous micro ozone bubbles was increased dramatically in the PHOC system, and oxidation potential was enhanced by increased ozone concentrations in the ozone contact tank. Thus, it is understood that the PHOC method is a more efficient system for ozone application than the traditional MOC system in drinking water treatment process.
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Mohammadi, Hossein, H. Bogac Poyraz, Deepak Ravindra i John A. Patten. "An Experimental Study on Single Point Diamond Turning of an Unpolished Silicon Wafer via Micro-Laser Assisted Machining". Advanced Materials Research 1017 (wrzesień 2014): 175–80. http://dx.doi.org/10.4028/www.scientific.net/amr.1017.175.
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Single Pointe Diamond Turning (SPDT) of silicon can be an extremely abrasive process due to the hardness of this material. In this research SPDT is coupled with the micro-laser assisted machining (μ-LAM) technique to machine an unpolished single crystal silicon (Si) wafer. Si is increasingly being used for industrial applications as it is hard, strong, inert, light weight and has great optical and electrical properties. Manufacturing this material without causing surface and subsurface damage is extremely challenging due to its high hardness, brittle characteristics and poor machinability. However, ductile regime machining of Si is possible due to the high pressure phase transformation (HPPT) occurring in the material caused by the high compressive and shear stresses induced by the single point diamond tool tip. The μ-LAM system is used to preferentially heat and thermally soften the workpiece material in contact with a diamond cutting tool. Different outputs such as surface roughness (Ra, Rz) and depth of cuts (DoC) for different set of experiments with and without laser were analyzed. Results show that an unpolished surface of a Si wafer can be machined in two passes to get a very good surface finish.
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Wang, Jie, Lulu Liu, Jun Yang, Sasa Yang, Hongwei Zhang, Hui Jia i Xingfei Guo. "Using magnetic powder to enhance coagulation membrane filtration for treating micro-polluted surface water". Water Supply 16, nr 1 (8.08.2015): 104–14. http://dx.doi.org/10.2166/ws.2015.112.
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The magnetic enhanced coagulation membrane filtration (MECMF) process was introduced into micro-polluted surface water treatment. The process was conducted by adding magnetic powder (MP) for enhancing coagulation. By contrasting the water quality parameters including dissolved organic carbon (DOC), UV254 and turbidity of permeates of MECMF and coagulation/flocculation membrane filtration (CFMF), results showed that the removal efficiency in the MECMF process was higher than those in the CFMF process. According to normalized flux and resistance analysis, membrane flux declined relatively slow and irreversible fouling resistance was lesser in the MECMF process. By analyzing the three-dimensional fluorescence of permeates and raw water, it was clearly shown that the permeate quality of the MECMF process was superior to that of the CFMF process apparently, which highlighted the removal of protein-like substances was more effectively in MECMF. Furthermore, the addition of MP could provide Lorentz and magnetic dipole forces between colloidal matters during coagulation, leading to the increase of collision frequency and efficiency and the formation of large size flocs with high fractal dimension. Large and high fractal dimension flocs could form a porous cake layer, which could increase water permeability. On the basic of the above findings, it was suggested that magnetic-enhanced coagulation that promoted flocs to develop could regulate cake layer structure and mitigate membrane fouling to some extent.
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Rogóż, Mikołaj, Zofia Dziekan, Klaudia Dradrach, Michał Zmyślony, Paweł Nałęcz-Jawecki, Przemysław Grabowski, Bartosz Fabjanowicz, Magdalena Podgórska, Anna Kudzia i Piotr Wasylczyk. "From Light-Powered Motors, to Micro-Grippers, to Crawling Caterpillars, Snails and Beyond—Light-Responsive Oriented Polymers in Action". Materials 15, nr 22 (18.11.2022): 8214. http://dx.doi.org/10.3390/ma15228214.
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“How would you build a robot, the size of a bacteria, powered by light, that would swim towards the light source, escape from it, or could be controlled by means of different light colors, intensities or polarizations?” This was the question that Professor Diederik Wiersma asked PW on a sunny spring day in 2012, when they first met at LENS—the European Laboratory of Nonlinear Spectroscopy—in Sesto Fiorentino, just outside Florence in northern Italy. It was not just a vague question, as Prof. Wiersma, then the LENS director and leader of one of its research groups, already had an idea (and an ERC grant) about how to actually make such micro-robots, using a class of light-responsive oriented polymers, liquid crystal elastomers (LCEs), combined with the most advanced fabrication technique—two-photon 3D laser photolithography. Indeed, over the next few years, the LCE technology, successfully married with the so-called direct laser writing at LENS, resulted in a 60 micrometer long walker developed in Prof. Wiersma’s group (as, surprisingly, walking at that stage proved to be easier than swimming). After completing his post-doc at LENS, PW returned to his home Faculty of Physics at the University of Warsaw, and started experimenting with LCE, both in micrometer and millimeter scales, in his newly established Photonic Nanostructure Facility. This paper is a review of how the ideas of using light-powered soft actuators in micromechanics and micro-robotics have been evolving in Warsaw over the last decade and what the outcomes have been so far.
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Neal, C. "The potential for phosphorus pollution remediation by calcite precipitation in UK freshwaters". Hydrology and Earth System Sciences 5, nr 1 (31.03.2001): 119–31. http://dx.doi.org/10.5194/hess-5-119-2001.
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Abstract. This paper examines the potential for calcium carbonate to reduce phosphate pollution in freshwaters by co-precipitation, a process known as a "self cleansing mechanism". Calcium carbonate saturation levels and phosphate concentrations (SRP - soluble reactive phosphate) across the major eastern UK river basins are examined to test for solubility controls. The study shows that calcite saturation varies for each catchment as a function of flow and biological activity rather than by direct regulation by SRP. Indeed, there is no evidence, for any of the rivers studied, that calcite solubility controls hold. However, for groundwater and groundwater-fed springs in the Chalk of the Thames basin, calcite saturation is observed with associated low SRP levels. A self-cleansing mechanism may well be operative within the Chalk due to two factors. Firstly, there is a high potential for nucleation on the calcite micro-crystals in the aquifer. Secondly, there are within aquifer reactions that remove the calcite nucleating inhibitors (SRP and dissolved organic carbon, DOC) to levels lower than those occurring within the rivers do. These inhibitors enter the catchment at very high concentrations in association with agricultural pollution (fertilizer application and animal slurry) and household contamination (e.g. sewage sources from septic tanks). Under low flow conditions, when the saturation index for calcite is at its highest, so too is the concentration of the nucleation inhibitor SRP. Companion work shows that calcite precipitation can occur at the water-sediment interface of the river and this may involve SRP removal. The data, as a whole, define an apparent bound for calcite solubility control where in the presence of nucleating centres, SRP must be less than 4 mM-P l-1 and DOC must be less than 150 mM-C l-1: a condition that does not seem to pertain within most UK rivers. Keywords: calcite, calcium carbonate, phosphate, soluble reactive phosphate, dissolved organic carbon, LOIS, UK, rivers, self-cleansing mechanisms.
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Chen, Ming, Shuhuai Shen, Fan Zhang, Cong Zhang i Jianglei Xiong. "Biodegradable Dissolved Organic Carbon (BDOC) Removal from Micro-Polluted Water Source Using Ultrafiltration: Comparison with Conventional Processes, Operation Conditions and Membrane Fouling Control". Polymers 14, nr 21 (3.11.2022): 4689. http://dx.doi.org/10.3390/polym14214689.
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The biodegradable dissolved organic carbon (BDOC) in micro-polluted water sources affects the drinking water quality and safety in the urban water supply. The conventional technology of “coagulation-sedimentation-filtration” in a water plant located in the lower reaches of the Yangtze River removed dissolved organic carbon (DOC) with a molecular weight (MW) > 30 kDa effectively, but the BDOC elimination only ranged 27.4–58.1%, due to their predominant smaller MW (<1 kDa), leading to a high residual BDOC of 0.22–0.33 mg/L. To ensure the biological stability of drinking water, i.e., the inability to support microbial growth (BDOC < 0.2 mg/L), a pilot-scale ultrafiltration process (UF, made of aromatic polyamide with MW cut-off of 1 kDa) was operated to remove BDOC as an advanced treatment after sand-filtration. Results showed the membrane flux decreased with the increase in the influent BDOC concentration and decrease in operating pressure. With an operating pressure of 0.25 MPa, the BDOC removal by UF reached 80.7%, leading to a biologically stable BDOC concentration of 0.08 mg/L. The fouling of the membrane was mainly caused by organic pollution. The H2O2–HCl immersion washing method effectively cleaned the membrane surface fouling, with a recovery of membrane flux of 98%.
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Khorshed, C., S. Vigneswaran, J. Kandasamy, R. Aryal i D. Dharmapalan. "Assessment of water treatment processes: detailed organic matter characterisation and membrane fouling indices at the Loddon Water Treatment Plant, Victoria, Australia". Water Supply 11, nr 3 (1.07.2011): 274–80. http://dx.doi.org/10.2166/ws.2011.040.
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Recent advances in membrane technology have led to its broad application, and reverse osmosis (RO) systems now represent the fastest growing segment of the desalination market. Its performance is hindered by membrane fouling. In this study pre-treatment methods to reduce RO fouling were investigated including flocculation, adsorption and ion exchange. Detailed organic characterisations were made in terms of florescence spectroscopy excitation emission matrix (EEM), UV254 absorbance and liquid chromatography-organic carbon detection (LCOCD). The different pre-treatment methods were assessed in terms of the fouling potential. This was quantified in terms of the modified fouling index measured using a dead-end cell micro-filtration (MF) unit. The existing pre-treatment of granular activated carbon (GAC) filter led to a good organic removal. Among the pre-treatment methods tested in the laboratory, purolite ion exchange/adsorption was found to be better than FeCl3 flocculation in terms of the amount as well as the wide range of organics removal. A pre-treatment of flocculation with Poly-ferric-silicate (PFSi) as flocculent gave a higher removal of organic matter compared to other pre-treatments tested. DOC was reduced from 11.5 to 4.25 mg/L, and it removed mostly the humic type substances.
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Wu, Y., X. Huang, X. Wen i F. Chen. "Function of dynamic membrane in self-forming dynamic membrane coupled bioreactor". Water Science and Technology 51, nr 6-7 (1.03.2005): 107–14. http://dx.doi.org/10.2166/wst.2005.0628.
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The Self-Forming Dynamic Membrane Coupled Bioreactor (SFDMBR), which uses coarse pore-sized material to separate solid and liquid in bioreactors, has some advantages compared with MBR using micro-/ultra-filtration membranes, for example, low module cost and high flux. The cake layer and gel layer formed on the surface and in the pores of the material during filtration played an important role, called self-forming dynamic membrane (DM), which mainly consisted of activated sludge. In this study, the function of DM in pollutant removal was investigated. It was found that DM could remove some organic matter (12.6 mg L−_rm;1 on average) and total nitrogen (3.01 mg L−_rm;1 on average) in the supernatant. Colloids and organic nitrogen were partly removed by DM while DOC, ammonia nitrogen and nitrate nitrogen removal by DM varied from negative to positive, which resulted from the combination of various biological activities, e.g. nitrification, biological utilization and so on. DO concentration in DM decreased with the depth and reached zero at about 1.5–2.5 mm depth. The organic degradation activity and nitrification activity of the biomass suspended in the bioreactor were higher than those of the biomass in the cake layer, which might be caused by the low DO concentration and low organic pollutant content in DM.
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Rawlings, M. M., C. S. B. Fitzpatrick, J. Gregory i A. Wetherill. "The effect of polymeric flocculants on floc strength and filter performance". Water Science and Technology 53, nr 7 (1.03.2006): 77–85. http://dx.doi.org/10.2166/wst.2006.210.
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Polymeric flocculants are widely used throughout the water industry as flocculant aids, they are known to increase floc density and aid settlement in the clarification stage of the water treatment process. In this research, polymeric flocculants were used to improve floc strength prior to filtration on a dissolved air flotation (DAF) plant in an attempt to prevent filter breakthrough. A modified jar test procedure using a PDA (photometric dispersion analyser) optical flocculation monitor was developed in order to evaluate the system floc strength. Filtration trials were carried out on a pilot filter rig situated on a surface water treatment works in Yorkshire. The filter feed originated from the main plant filter channel. Filter performance was assessed by continuous online monitoring of effluent particle counts, turbidity and headloss over the period of the filter run. Results indicated that low doses of polymeric flocculants had a beneficial effect on filtered water quality, as measured by particle counts, turbidity, UV254 absorption and dissolved organic carbon (DOC). Polymeric flocculants also had the effect of extending filter run length. The modified jar test results indicated that the flocculants used improved the floc strength and enhanced reflocculation of the micro flocs present after the flotation process.
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Hameed, Azzam Sabah, Mohaned S. Jafar i Bijan Mallick. "Improvement of CNC Lathe Performances by Tungsten-Carbide Tool Using Desirability Function Analysis for Fabrication of Miniature Component". Materials Science Forum 1002 (lipiec 2020): 3–11. http://dx.doi.org/10.4028/www.scientific.net/msf.1002.3.
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Computer numerical control (CNC) machine has greater utility in the modern advanced industrial field. This paper deals with the parametric effects such as spindle speed (1500-2100 rpm) (N) (X1), depth of cut (DOC) (0.15-0.55 mm) (X2) and feed rate (f) (30-50 mm/min) (X3) on machining characteristics like tool wear rate (TWR) and surface roughness (Ra) during fabrication of IS-617 Aluminum miniature component by advanced CNC lathe using Tungsten-carbide tool. The article analyzes the second-order mathematical model development with co-relation of co-efficient of regression (COR) and analysis of variances (ANOVA) using desirability function analysis during the production of the miniature segment. The paper also consists of multi-criteria optimization for achieving the optimal parametric combination for minimum surface roughness and tool wear rate for this manufacturing operation. The paper also shows the fabricated micro-product of Aluminum at the optimal parametric conditions using CNC programming. It is found that spindle speed has a greater effect on the tool wear rate and depth of cut has dominating effects on surface roughness of job specimen. Desirability parametric combination for minimized surface roughness as well as tool wear rate has been found 1523 rpm/0.15mm/30mmmin-1.
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Modolo, Julien, Mahmoud Hassan, Fabrice Wendling i Pascal Benquet. "Decoding the circuitry of consciousness: From local microcircuits to brain-scale networks". Network Neuroscience 4, nr 2 (styczeń 2020): 315–37. http://dx.doi.org/10.1162/netn_a_00119.
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Identifying the physiological processes underlying the emergence and maintenance of consciousness is one of the most fundamental problems of neuroscience, with implications ranging from fundamental neuroscience to the treatment of patients with disorders of consciousness (DOCs). One major challenge is to understand how cortical circuits at drastically different spatial scales, from local networks to brain-scale networks, operate in concert to enable consciousness, and how those processes are impaired in DOC patients. In this review, we attempt to relate available neurophysiological and clinical data with existing theoretical models of consciousness, while linking the micro- and macrocircuit levels. First, we address the relationships between awareness and wakefulness on the one hand, and cortico-cortical and thalamo-cortical connectivity on the other hand. Second, we discuss the role of three main types of GABAergic interneurons in specific circuits responsible for the dynamical reorganization of functional networks. Third, we explore advances in the functional role of nested oscillations for neural synchronization and communication, emphasizing the importance of the balance between local (high-frequency) and distant (low-frequency) activity for efficient information processing. The clinical implications of these theoretical considerations are presented. We propose that such cellular-scale mechanisms could extend current theories of consciousness.
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Liao, X. B., X. J. Zhang, J. Wang, X. B. Li, C. K. Wang i C. Chen. "Application of conventional and O3-BAC processes to treat organic matter and antibiotic pollutants in a lake in East China". Water Supply 13, nr 6 (13.09.2013): 1470–77. http://dx.doi.org/10.2166/ws.2013.155.
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The occurrence and treatment of antibiotics in a micro-polluted lake which serves as a drinking water source in East China was surveyed. A pilot plant with conventional and O3-BAC (biological activated carbon) processes was set up to investigate its effectiveness in dealing with the contaminants. Solid phase extraction (SPE) coupled with electro-spray ionization-tandem mass spectrometry (LC-ESI-MS-MS) was applied to detect various antibiotics simultaneously. Three groups of antibiotics, i.e. sulfonamides, fluoroquinolones and tetracyclines, were detected in the source water. The gross concentrations of them in the lake are up to 471, 23.4 and 1,039 ng/L, respectively. The conventional and O3-BAC processes could remove 78.9, 62.4 and 70.2% of them, respectively. Among the antibiotics, tetracyclines could be effectively removed by ozonation, while fluoroquinolones could be removed by the coagulation–sedimentation process. BAC could not degrade fluoroquinolones but enabled the reduction of the other two antibiotics. In addition, O3-BAC was an effective technology for the removal of bulk organic matter. The concentrations of chemical oxygen demand (CODMn), UV254 and dissolved organic carbon (DOC) in the effluent of the up-flow BAC process were 2.31 mg/L, 0.034 cm−1 and 1.76 mg/L, respectively, with the corresponding removal rates of 45.1, 67.3 and 65.1%, respectively. In all, the combined conventional and O3-BAC process was the best available technology to remove organic matter as well as antibiotics.
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Pi, Jiachang, Guangcan Zhu, Lianqing Liu, Chuya Wang i Zhonglian Yang. "Size and resin fractionations of dissolved organic matter and characteristics of disinfection by-product precursors in a pilot-scale constructed wetland". Water Supply 21, nr 4 (20.01.2021): 1481–94. http://dx.doi.org/10.2166/ws.2021.013.
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Abstract Controlling the formation of disinfection by-products (DBPs) is a major issue in the drinking water industry, and understanding the characteristics of DBP precursors in treatment processes for micro-polluted raw water is key to improving water quality. In this study, a sampling program was undertaken to investigate the fate of dissolved organic matter (DOM) and the characteristics of DBP precursors in a pilot constructed wetland imitating the Yanlong Lake ecological project. Using XAD resin adsorption and ultrafiltration techniques, the dissolved organic carbon, UV254, and DBP formation potential (DBPFP) were measured in different DOM fractions in raw water and wetland effluents. After the constructed wetland treatment, the low molecular weight fraction (<3 kDa) of DOM and DBPFP generally showed a decreasing trend along the water path, while the high molecular weight fraction (>3 kDa) of DOM increased. The specific DBPFP (SDBPFP) was much higher in the <1 kDa fraction than in the other fractions. Although the hydrophobic fraction of DOM was the most abundant in all stages of the wetland treatment, the SDBPFP of the hydrophilic fraction was higher than that of the hydrophobic fraction. Furthermore, compared with raw water, the DOC, UV254 and DBPFP in the treated wetland effluents increased; however, all of the chemical DOM fractions exhibited decreased SDBPFP in accordance with a decrease in the specific ultraviolet absorbance during wetland treatment. These conclusions indicate that the DOM produced by the wetland system may generate DBPs less readily compared with the DOM of raw water.
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Schlich, Karsten, Cecilia Díaz, Benjamin Gomez Pizarro, Burkhard Knopf, Ruben Schlinkert, Franziska Frederike Wege, Anne Jurack i Kerstin Hund-Rinke. "Microbial Population Dynamics in Model Sewage Treatment Plants and the Fate and Effect of Gold Nanoparticles". Toxics 9, nr 3 (10.03.2021): 54. http://dx.doi.org/10.3390/toxics9030054.
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Adequate functioning of a sewage treatment plant (STP) is essential to protect the downstream aquatic environment (ECHA 2017), and information on the degradability of chemicals and their toxicity to activated sludge microorganisms is required. An environmental realistic higher tier test is a STP simulation test as described in OECD 303A (2001) which for nanoparticles can also be used to study their sorption behavior to activated sludge. However, information is limited on the influence of synthetic sewage on the microbial community of the activated sludge. A modified community can result in modifications of the sludge floccules affecting the sorption behavior. The main objective of our study was to show whether a representative microbial diversity remains under standardized test conditions as described in OECD 303A (2001) using synthetic sewage as influent. Furthermore, we investigated whether just considering the functional properties of a STP (elimination of dissolved organic carbon; nitrification), is sufficient for an assessment of gold nanoparticles (AuNPs) or whether the influence on microbial diversity also needs to be considered. AuNPs were used as a case study due to their rising medical applications and therefore increasing probability to reach the sewer and STP. The results can provide significant input for the interpretation of results from the regulatory point of view. To deliver these objectives, the general changes of the microbial population in activated sludge and its influence on the degradation activity (dissolved organic carbon (DOC) and inorganic nitrogen) using freshly collected sludge from the municipal STP in an artificial test system as a model STP in accordance with OECD 303A (2001) were assessed. Additionally, we evaluated the potential impact of AuNPs and its dispersant on the microbial composition and the overall impact on the function of the STP in terms of DOC degradation and nitrogen removal to observe if an assessment based on functional properties is sufficient. The bacteria composition in our study, evaluated at a class level, revealed commonly described environmental bacteria. Proteobacteria (β, α, δ) accounted for more than 50% but also nitrifying bacteria as Nitrospira were present. Our results show that mainly within the first 7 days of an acclimatization phase by addition of synthetic sewage, the bacterial community changed. Even though AuNPs can have antibacterial properties, no adverse effects on the function and structure of the microorganisms in the STP could be detected at concentrations of increased modeled PEC values by a factor of about 10,000. Complementary to other metallic nanomaterials, gold nanomaterials also sorb to a large extent to the activated sludge. If activated sludge is used as fertilizer on agricultural land, gold nanoparticles can be introduced into soils. In this case, the effect on soil (micro)organisms must be investigated more closely, also taking into account the structural diversity.
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Maßmig, Marie, Jan Lüdke, Gerd Krahmann i Anja Engel. "Bacterial degradation activity in the eastern tropical South Pacific oxygen minimum zone". Biogeosciences 17, nr 1 (17.01.2020): 215–30. http://dx.doi.org/10.5194/bg-17-215-2020.
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Abstract. Oxygen minimum zones (OMZs) show distinct biogeochemical processes that relate to microorganisms being able to thrive under low or even absent oxygen. Microbial degradation of organic matter is expected to be reduced in OMZs, although quantitative evidence is low. Here, we present heterotrophic bacterial production (3H leucine incorporation), extracellular enzyme rates (leucine aminopeptidase/β-glucosidase) and bacterial cell abundance for various in situ oxygen concentrations in the water column, including the upper and lower oxycline, of the eastern tropical South Pacific off Peru. Bacterial heterotrophic activity in the suboxic core of the OMZ (at in situ ≤ 5 µmol O2 kg−1) ranged from 0.3 to 281 µmol C m−3 d−1 and was not significantly lower than in waters of 5–60 µmol O2 kg−1. Moreover, bacterial abundance in the OMZ and leucine aminopeptidase activity were significantly higher in suboxic waters compared to waters of 5–60 µmol O2 kg−1, suggesting no impairment of bacterial organic-matter degradation in the core of the OMZ. Nevertheless, high cell-specific bacterial production was observed in samples from oxyclines, and cell-specific extracellular enzyme rates were especially high at the lower oxycline, corroborating earlier findings of highly active and distinct micro-aerobic bacterial communities. To assess the impact of bacterial degradation of dissolved organic matter (DOM) for oxygen loss in the Peruvian OMZ, we compared diapycnal fluxes of oxygen and dissolved organic carbon (DOC) and their microbial uptake within the upper 60 m of the water column. Our data indicate low bacterial growth efficiencies of 1 %–21 % at the upper oxycline, resulting in a high bacterial oxygen demand that can explain up to 33 % of the observed average oxygen loss over depth. Our study therewith shows that microbial degradation of DOM has a considerable share in sustaining the OMZ off Peru.
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Ibrahim Irka, Chaher, Pascale Prudent, Frédéric Théraulaz, Anne-Marie Farnet Da Silva, Laurence Asia, Didier Gori, Laurent Vassalo i in. "Treatment of Sewage Sludge Compost Leachates on a Green Waste Biopile: A Case Study for an On-Site Application". Processes 10, nr 6 (15.06.2022): 1196. http://dx.doi.org/10.3390/pr10061196.
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This work proposes a suitable treatment for the leachates from a sewage sludge composting process using a specific windrow (biopile). The biopile’s evolution and organic content degradation were followed for 2 months with regular leachate spraying to assess the physico-chemical and biological impacts, and determine the risk of enrichment with certain monitored pollutants. The final objective was the valorization of the biopile substrates in the composting process, while respecting the quality standards of use in a circular economy way. Classical physico-chemical parameters (pH, conductivity, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), etc.) were measured in the leachates and in the water-extractable and dry-solid fractions of the biopile, and the catabolic evolution of the micro-organisms (diversity and activities), as well as the enrichment with persistent organic pollutants (POPs) (prioritized PAHs (polycyclic aromatic hydrocarbons) and PCBs (polychlorinated biphenyls)), were determined. The results showed that the microbial populations that were already present in the biopile, and that are responsible for biodegradation, were not affected by leachate spraying. Even when the studied compost leachate was highly concentrated with ammonium nitrogen (10.4 gN L−1 on average), it significantly decreased in the biopile after 2 weeks. A study on the evolution of the isotopic signature (δ15 N) confirmed the loss of leachate nitrogen in its ammoniacal form. The bio-physico-chemical characteristics of the biopile at the end of the experiment were similar to those before the first spraying with leachate. Moreover, no significant enrichment with contaminants (metal trace elements, volatile fatty acids, or persistent organic pollutants) was observed. The results show that it would be possible for composting platforms to implement this inexpensive and sustainable process for the treatment of leachates.
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Mufidah, Ainin Nur, Hammis Syafaq i Ana Toni Roby Candra Yudha. "INTEGRATED ECONOMIC EMPOWERMENT: EVIDENCE IN THE RELIGIOUS AREA OF GUSDUR'S TOMB". Jurnal Ekonomi Syariah Teori dan Terapan 8, nr 6 (5.12.2021): 785. http://dx.doi.org/10.20473/vol8iss20216pp785-796.
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ABSTRAKSaat ini wisata syariah yang biasa dikenal dengan wisata religi sedang menjamur, khususnya di Jawa Timur. Sosok yang dianggap wali oleh sebagian orang itu berada di Surabaya, Gresik, dan Tuban, namun saat ini berkembang di kabupaten Jombang, yakni makam Presiden ke-4 Abdurrahman Wahid yang disebut Gus Dur. Penelitian ini bertujuan untuk mengetahui pemahaman masyarakat dalam memanfaatkan peluang wisata religi makam Gus Dur dalam meningkatkan perekonomian masyarakat sekitar pondok pesantren Tebuireng khususnya di dusun Jalan Seblak gang III. Penelitian ini dapat dicermati melalui perubahan kehidupan ekonomi, pemanfaatan peluang usaha dan faktor penghambat bagi kepentingan usaha. Penelitian ini menggunakan metode deskriptif kualitatif dengan teknik pengumpulan data wawancara dan dokumentasi. Hasil penelitian ini menunjukkan bahwa masyarakat setempat mengalami perubahan ekonomi dengan memanfaatkan peluang untuk membangun warung di atas tanah mereka dan menyewakannya kepada pedagang luar. Ini memberikan nilai ekonomi tambahan. Namun, penjualan warung-warung tersebut dinilai tidak mencukupi, sehingga mengharuskan mereka untuk membuka usaha sampingan. Terdapat peluang yang sangat baik bagi masyarakat untuk memilih menyewakan lapaknya karena faktor penghambat yaitu keluarga, tenaga kerja, permodalan, dan rasa empati yang tinggi terhadap pedagang pendatang. Saran bagi Pemerintah Kabupaten Jombang adalah memfasilitasi masyarakat dengan pengetahuan kewirausahaan dengan mengadakan seminar agar memiliki pengetahuan dan motivasi yang tinggi untuk menjalankan bisnis.Kata Kunci: Wisata Religi Makam Gus Dur, Peningkatan Ekonomi, Peluang Usaha. ABSTRACTCurrently, sharia tourism, commonly known as religious-friendly tourism is proliferating, especially in East Java. The figure, who is considered a guardian by some people, is located in Surabaya, Gresik, and Tuban but currently developing in the Jombang district, namely the tomb of the 4th President Abdurrahman Wahid, who is called Gus Dur. This study aims to determine the understanding of the community in taking advantage of religious tourism opportunities in Gus Dur's tomb in improving the community's economy around the Tebuireng Islamic boarding school, especially in the hamlet of Street Seblak street alley III. This study can be observed through changes in economic life, utilization of business opportunities and inhibiting factors for business interests. This study uses a qualitative descriptive method with interview and documentation data collection techniques. The results of this study show that the local community is experiencing economic changes by taking advantage of the opportunity to build a warung on their land and rent it out to outside traders. It provides added economic value. However, the sales of the stalls are considered insufficient, so they require them to open a side business. There is an excellent opportunity for the community to choose to rent out their stalls because of the inhibiting factors, namely family, labour, capital, and a high sense of empathy for migrant traders. The suggestion for the Jombang Regency Government is to facilitate the community with entrepreneurial knowledge by holding seminars to have high knowledge and motivation for business interests.Keywords: Religion Tourism of Gus Dur Tomb, Economic Improvement, Business Opportunity. REFERENCESAbdi, M. K., & Febriyanti, N. (2020). Penyusunan strategi pemasaran islam dalam berwirausaha di sektor ekonomi kreatif pada masa pandemi covid-19. El Qist - Journal of Islamic Economics and Business, 10(2), 160–179.Abduh, M. (2019). The role of Islamic social finance in achieving SDG Number 2: End hunger, achieve food security and improved nutrition and promote sustainable agriculture. Al-Shajarah, Special Issue Islamic Banking and Finance 2019, 185–206.Alifianingrum, R., & Suprayogi, N. (2018). Faktor-faktor yang mempengaruhi surplus underwriting dana tabarru’ pada perusahaan asuransi jiwa syariah. Jurnal Ekonomi Syariah Teori Dan Terapan, 5(2), 144–158. https://e-journal.unair.ac.id/JESTT/article/view/13372Amalia, S. (2018). Reformasi birokrasi 4.0: Strategi menghadapi revolusi industri 4.0. Jurnal Wacana Kinerja: Kajian Praktis-Akademis Kinerja Dan Administrasi Pelayanan Publik. https://doi.org/10.31845/jwk.v21i2.133Chitrakorn, K. (2015). Can halal cosmetics outgrow their niche? Retrieved from https://www.businessoffashion.com/articles/beauty/can-halal-cosmetics-outgrow-their-niche/.De Boni, A., & Forleo, M. B. (2019). Italian halal food market development: drivers and obstacles from experts’ opinions. Journal of Islamic Marketing, 10(4), 1245–1271. https://doi.org/10.1108/JIMA-05-2018-0087Diniyya, A. A. (2019). Development of waqf based microfinance and its impact in alleviating the poverty. Ihtifaz: Journal of Islamic Economics, Finance, and Banking, 2(2), 107. https://doi.org/10.12928/ijiefb.v2i2.879Djawahir, A. U. (2018). Teknologi-layanan keuangan, literasi-inklusi keuangan, dan value pada fintech syariah di Indonesia: Perspektif S-O-R (Stimulus-organism-response) model. 2nd Proceedings Annual Conference for Muslim Scholars, April 2018, 439–448.Fatmawati, A., Yudha, A. T. R. C., & Syafaq, H. (2020). Kontrak kerja dan kesejahteraan ABK nelayan perspektif etika bisnis Islam di Sarangmerduro, Jawa Tengah. Nukhbatul ’Ulum: Jurnal Bidang Kajian Islam, 6(2), 298–313.Fitriani, H. (2018). Proyeksi potensi pengembangan pariwisata perhotelan dengan konsep syariah. Muslim Heritage, 3(1), . https://doi.org/10.21154/muslimheritage.v3i1.1257Indrawati, S. M., Diop, N., Ikhsan, M., & Kacaribu, F. (2020). Enhancing resilience to turbulent global financial markets: An Indonesian experience. Economics and Finance in Indonesia, 66(1), 47–63.Kraus, S., Clauß, T., Breier, M., Gast, J., & Tiberius, V. (2020). The economics of covid-19: Initial empirical evidence on how family firms in five European countries cope with the corona crisis. International Journal of Entrepreneurial Behaviour & Research, 26(5), 1067-1092. https://doi.org/10.1108/IJEBR-04-2020-0214Miftakhul Jannah, D., & Nugroho, L. (2019). Strategi meningkatkan eksistensi asuransi syariah di Indonesia. Jurnal Maneksi, 8(1), 169–176.Muhamed, A. A., Ab Rahman, M. N., Mohd Hamzah, F., Che Mohd Zain, C. R., & Zailani, S. (2019). The impact of consumption value on consumer behaviour: A case study of halal-certified food supplies. British Food Journal, 121(11), 2951–2966. https://doi.org/10.1108/BFJ-10-2018-0692Nursafitri, S., & Yudha, A. T. R. C. (2020). Instrumen moneter dan belanja daerah serta pengaruhnya terhadap pengangguran terbuka. Ekonomi Dan Bisnis, 7(2), 121–136. https://doi.org/10.35590/jeb.v6i2.1649Nusa, A. T. S., & Khoirudin, R. (2020). Analisis determinan PAD sub-sektor pariwisata di DIY tahun 2012-2017. Journal of Economics Development Issues (JEDI), 3(1), 1–13. https://doi.org/https://doi.org/10.33005/jedi.v3i01.45Rijal, A. (2018). Pengetahuan konsumen terhadap IB Hasanah Card Bank BNI Syariah Cabang Surabaya. Adilla: Jurnal Ilmiah Ekonomi Syari'ah, 1(1), 117–139.Ryandono, M. N. H. (2018). FinTech waqaf : Solusi permodalan perusahaan startup wirausaha muda, 7(2), 111–121. DOI: https://doi.org/10.22146/studipemudaugm.39347Standard, D. (2019). State of the global islamic economy report 2019/20. Dubai International Financial Centre, 1–174. https://haladinar.io/hdn/doc/report2018.pdfSukoco, A., Anshori, Y., & Yudha, A. T. R. C. (2020). Strategies to increase market share for histopatological equipment products (Brand Sakura): Case Study in management of a sole agent company. SINERGI, 10(2), 19–26.Usman, H., Sobari, N., & Sari, L. E. (2019). Sharia motivation in Muslim tourism definition, is it matter? Journal of Islamic Marketing, 10(3), 709–723. https://doi.org/10.1108/JIMA-01-2018-0015Wahyu Puspitasari, A. (2017). Optimizing productive land waqf towards farmers prosperity. Journal of Indonesian Applied Economics, 7(1), 103–112. https://doi.org/10.21776/ub.jiae.2017.007.01.7Yalina, N., Kartika, A. P., & Yudha, A. T. R. C. (2020). Impact analysis of digital divide on food security and poverty in Indonesiain 2015-2017. Jurnal Manajemen Teknologi, 19(2), 145–158. https://doi.org/http://dx.doi.org/10.12695/jmt.2020.19.2.3Yudha, A. T. R. C., Harisah, Santoso, I. R., Mukr, S. G., Zibbri, M., Firdaus, N. N., Hidayatullah, A., Hasani, J. E., Adam, M., Hamzah, M. M., Dian, C., Wijayanti, D. M., Fahrurrozi, & Zaini, M. (2020). Bisnis, Keuangan, Ekonomika Islam dan Covid-19: Merumuskan teori dan model bisnis, keuangan dan ekonomika islam dalam mengatasi krisis ekonomi akibat pandemi Covid-19. Jakarta: Kementerian Keuangan RI.Yudha, A. T. R. C., & Lathifah, N. (2018). Productive zakat as a fiscal element for the development and empowerment of micro enterprises in East Java Province. International Conference of Zakat. DOI: https://doi.org/10.37706/iconz.2018.123Yudha, A. T. R. C., & Muizz, A. (2020). Optimalisasi potensi lahan pertanian untuk ketahanan pangan di Kecamatan Panceng, Gresik, Jawa Timur. Journals of Economics Development Issues ( JEDI ), 3(2), 297–308. https://doi.org/https://doi.org/10.33005/jedi.v3i2.55Yudha, A. T. R. C., Pauzi, N. S., & Azli, R. binti M. (2020). The Synergy Model for Strengthening the Productivity of Indonesian Halal Industry. Al-Uqud: Journal of Islamic Economics, 4(2), 186–199. https://doi.org/10.26740/al-uqud.v4n2.p186-199Yudha, A. T. R. C., Ryandono, M. N. H., Rijal, A., & Wijayanti, I. (2020). Financing model to develop local commodity business of East Java in Maqashid Syariah perspective. Test Engineering and Management, 83(3590), 3590–3595.
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Olaya Delgado, Nancy, Adrián David Vargas i Yhonatan Saúl Jiménez Calderón. "La responsabilidad social empresarial en La Amazonía". Revista UNIMAR 36, nr 1 (29.10.2018): 12. http://dx.doi.org/10.31948/unimar.36-1.7.
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Hoy por hoy, la responsabilidad social empresarial (RSE) es una nueva forma de enfocar las organizaciones, y de tener un poco de conciencia o respeto hacia los diferentes medios o entornos en los cuales éstas desarrollan sus actividades empresariales. Aparte de ello se puede mencionar que, aunque no existe una gran cantidad de organizaciones pertenecientes al sector secundario, encargado de transformar la materia prima en un bien final, existe una amplia cantidad de pequeñas y medianas empresas (Pymes) del sector primario en la región amazónica, que realizan actividades como la extracción de madera, carbón, peces, producción de ganado, entre otras, acciones que perjudican toda la biodiversidad de la Amazonía colombiana. El presente artículo es de enfoque cualitativo y tipo metodológico descriptivo, ya que se buscó caracterizar el impacto de la RSE en la Amazonía colombiana por parte de las pequeñas y medianas empresas.
Referencias:
Acero, R. (2016). Lineamientos estratégicos para la incorporación congruente de la variable ambiental en los planes y esquemas de ordenamiento territorial de Colombia (Tesis de Maestría). Universidad de Chile. Recuperado de http://mgpa.forestaluchile.cl/Tesis/Acero%20Ronald.pdf
Agudelo, E. (2015). Bases científicas para contribuir a la gestión de la pesquería comercial de bagres (familia pimelodidae) en la Amazonía colombiana y sus zonas de frontera. Recuperado de https://ddd.uab.cat/record/142475
Agudelo, S. (2009). Responsabilidad Social Empresarial, Una mirada desde Colombia. Revista de Negocios Internacionales, 2(1), 3‐11.
Altuna, M. (2013). Los Factores de la Responsabilidad Social: El Análisis de las Pequeñas y Medianas Empresas Manufactureras Guipuzcoanas. Azkoaga, 16, 149-172.
Anónimo. (s.f.). La RSE. “Modelo de Buena Práctica Empresarial”. Recuperado de https://aprendeenlinea.udea.edu.co/revistas/index.php/ tgcontaduria/article/viewFile/323512/20780676
Arenas, A., Escobar, E., Acosta, J., Monsalve, L. y Oyola, E. (2012). RSE “Moda o Compromiso Real” (Trabajo de Grado). Universidad de Medellín. Medellín, Colombia. Recuperado de http://repository.udem.edu.co/bitstream/handle/11407/357/ Responsabilidad%20social%20empresarial.%20%E2%80%9CModa% 20o%20compromiso%20 real%E2%80%9D.pdf?sequence=1&isAllowed=y
Aristimuño, M. y Rodríguez, C. (2014), Responsabilidad social universitaria. Su gestión desde la perspectiva de directivos y docentes. Estudio de caso: una pequeña universidad latinoamericana. Interciencia, 39(6), 375-382.
Baltera, P., Díaz, E. y Dussert, J. (2005). Responsabilidad Social Empresarial, Alcances y Potencialidades en Materia Laboral. Cuaderno de Investigación N° 25. Recuperado de http://www.dt.gob.cl/portal/1626/articles-88984_recurso_1.pdf
Barrena, A. (2012). La protección de las especies silvestres, especial tratamiento de la protección en situ (Tesis doctoral). Universidad de Alicante. Recuperada de https://rua.ua.es/dspace/handle/10045/28038Bencomo, T. (2007). Desarrollo de las TIC y la formación profesional. http://www.saber.ula.ve/bitstream/handle/123456789/25149/articulo1.pdf; jsessionid=A8697326F48141C4F9366A86EA3CED46?sequence=2
Buriticá, L. (2011). La RSE y su Relación Teórica con la Gestión del Talento Humano. Universidad de Manizales (Tesis de Maestría). Universidad de Manizales. Recuperado de http://ridum.umanizales.edu.co:8080/xmlui/bitstream/handle/6789/297/Buritica_ Castro_Lida_Marcela_ 2011.pdf?sequence=
Camejo, A. y Cejas, M. (2009). Responsabilidad social: factor clave de la gestión de los recursos humanos en las organizaciones del siglo XXI. Nómadas, Critical Journal of Social and Juridical Sciences, 21(1), 127-142.
Cardona, C. y Giraldo, L. (2010). Estandarización de Indicadores de Responsabilidad Social Empresarial Propuestas por Organizaciones de Reconocimiento Mundial (Trabajo de Grado). Universidad Tecnológica de Pereira. Recuperado de http://repositorio.utp.edu.co/dspace/bitstream/handle/11059/1549/ 658408C268. pdf;jsessionid=A24F7FD84FFE4F942F3159EE7AB68BF7?sequence=1
Congreso de la República de Colombia. (2000). Ley 590 de 2000 “por la cual se dicta disposiciones para promover el desarrollo de las micro, pequeñas y medianas empresas”. Bogotá, Colombia. Recuperada de http://www.alcaldiabogota.gov.co/sisjur/normas/Norma1.jsp?i=12672
Curatola, G. (2011). Patrones de distribución espacial de Triplaris Americana en Tambopata, Perú. Pontificia Universidad Católica del Perú. Recuperado de http://tesis.pucp.edu.pe/repositorio/handle/123456789/454
De La Cuadra, F. (2013). Cambio climático, movimientos sociales y políticas públicas, una vinculación necesaria. Recuperado de https://journals.openedition.org/polis/9651
Delgado, V. y Olarte, M. (2012). Responsabilidad social corporativa en el sector de la televisión. Un estudio longitudinal de las memorias de sostenibilidad. Revista Internacional de Investigación en Comunicación aDResearch ESIC, 6(6), 112-129.
Delgado, Y., Herrera, N. y Gallón, C. (2014). La Responsabilidad Social Empresarial: una mirada a la aplicación en el sector transporte público automotor. Trabajos de Grado Contaduría Pública, 8(1), 1-29.
Duque, Y., Cardona, M. y Rendón, J. (2013). Responsabilidad Social Empresarial: Teorías, índices, estándares y certificaciones. Cuadernos de Administración, 29(50), 196-206.
Escamilla, S., Jiménez, I. y Prado, C. (2013). La Responsabilidad Social Empresarial, una forma de crear valor. Madrid, España: Editorial Académica Española.
Fernández, C. (2012). Responsabilidad Social Empresarial: Cultura y Medio ambiente (Tesis de Posgrado). Recuperado de http://repositorio.uchile.cl/handle/2250/112084
Franco, C. (s.f.). Dinámica de construcción de una nueva sociedad desde los negocios. Recuperado de http://interamerican-usa.com/articulos/Gob-Corp-Adm/Responsabilidad%20Social%20Carolina%20Franco[1].pdf
García, M. y Duque, J. (2012). Gestión Humana y Responsabilidad Social Empresarial: un enfoque estratégico para la vinculación de prácticas responsables a las Organizaciones. Libre Empresa, 17, 13-37.
Gil, F. (2013). La responsabilidad social universitaria desde la perspectiva ambiental: universidad y desarrollo sustentable (Tesis de Maestría). Universidad Nacional Autónoma de México. Recuperado de http://132.248.9.195/ptd2013/agosto/0700625/0700625.pdf
Gómez, M. (2010). La Gestión y la Información sobre la Responsabilidad Social Empresarial de las PYMES: la Necesidad de Diferenciación. Contaduría Universidad de Antioquia, 56, 15-40.
Gómez-Villegas, M. y Quintanilla, D. (2012). Los informes de Responsabilidad Social Empresarial: su evolución y tendencias en el contexto internacional colombiano. Cuadernos de Contaduría, 13(32), 121-158.
Gómez, H. (2014). Responsabilidad Social Empresarial en la municipalidad de Huehuetenango (Trabajo de Grado). Universidad Rafael Landívar. Recuperado de http://biblio3.url.edu.gt/Tesario/2014/01/01/Gomez-Helen.pdf
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Henao, J. (2013). La Responsabilidad Social Empresarial como Estrategia de Gestión en la Organización Pranha S.A. (Tesis de Maestría). Universidad Nacional de Colombia. Recuperado de http://www.bdigital.unal.edu.co/12095/1/7711507.2013.pdf
Lara, M. (2003). La responsabilidad social de la empresa: implicaciones contables. España: Editorial Edisofer S.L.
López, I. (2014). El cambio climático, ¿reto para la Responsabilidad Social Empresarial? Revista Internacional de Organizaciones, 13, 39-53.
Mantilla, M. (2012). Responsabilidad Social Empresarial y Población Indígena Colombiana. Bogotá, Colombia: Fondo de Publicaciones de la Universidad Sergio Arboleda.
Méndez-Beltrán, J. y Peralta-Borray, D. (2014). Reflexiones respecto a la Responsabilidad Social Empresarial y la creación de valor económico desde la perspectiva de los proveedores. Cuadernos de Contabilidad, 15(38), 625-645.
Meza, A. (2007). La Responsabilidad Social Empresarial como factor de competitividad (Trabajo de Grado). Pontificia Universidad Javeriana, Bogotá, Colombia. Recuperado de http://www.javeriana.edu.co/biblos/tesis/economia/tesis27.pdf
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"Assessment of the Effects of Physical Disturbances in Simple Micro-Universes by Measurement of DOC-levels". Earth & Environmental Science Research & Reviews 1, nr 1 (27.08.2018). http://dx.doi.org/10.33140/eesrr/01/01/00005.
Pełny tekst źródłaStreszczenie:
An increasing problem with today’s way of living is the rising of anthropologically influenced pollutions. Quite recently has research been directed towards the effects and consequences these disturbances may cause within freshwater environments, which has inspired this study. Hoping to assess the effects of different disturbances that are likely to occur in lakes, DOC-levels (Dissolved Organic Carbon) were measured to get an idea of what might happen to the microbial ecology when these are introduced. The research was conducted by introducing a heavy reduction of bacteria, micro plastics, SDS (Sodium dodecyl sulfate) and micro plastics and SDS together to enclosed environments. The purpose of this, and also the aims of this study being to 1) find out of DOC-levels were affected, if 2) a difference could be observed between exposure to micro plastics + SDS versus micro plastics and SDS alone, and 3) to assess the recovery after each disturbance. Following exposure DOC-levels remained generally unchanged in the reduced bacteria and micro plastics mesocosms, whereas these levels were heavily reduced after exposure to SDS. It was also found that SDS + micro plastics required a shorter exposure time before mortality was observed than SDS alone, and resulted in a much higher mortality rate than micro plastics alone.
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Jeong, Ji-Young, Jun Sae Han, Chung-Mo Kang, Eun-Ji Gwak, Doo-Sun Choi i Tae-Jin Je. "Investigation of ultra-precision planing process to fabricate high luminance retroreflector based on cutting force and tool vibration analysis". Scientific Reports 12, nr 1 (9.05.2022). http://dx.doi.org/10.1038/s41598-022-10824-6.
Pełny tekst źródłaStreszczenie:
AbstractIn ultra-precision planing process, the analysis of the critical depth of cut (DOC) is required to reduce the edge blunt and micro burrs produced by size effect which decreases of the effective area for high luminance retroreflector. However, since the machining characteristics are different according to cutting tool shape, machining material, and cutting condition, determine of the critical DOC is difficult without a comparison of machined surfaces under various DOC measured by ultra-high resolution measuring instrument. In this study, the critical DOC was analyzed using cutting force and tool vibration signals. The specific cutting energy was calculated by cutting force and cross-sectional area to analyze the stress variation according to DOC. Also, acceleration signals were converted to frequency spectrum that analyze dominant vibrating direction of the cutting tool by variation of cutting characteristic. It was confirmed that the method of using tool vibration more effective and accurate than specific cutting energy through validation of the comparison between results from analyze of the vibration signals and direction measuring surfaces. The master mold with area of 250 mm2 was manufactured by applying analyzed critical DOC. In addition, the high luminance characteristic of a retroreflection film press formed by the master mold was confirmed.
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Kim, Seung-Hyun, Sanggoo Kim, Hoonsik Yoom i Heejong Son. "Evaluation of organics reduction performance of the GAC filtration with regenerated carbons using the long-term operational data of drinking water treatment facilities". Journal of Water Supply: Research and Technology-Aqua, 11.10.2022. http://dx.doi.org/10.2166/aqua.2022.132.
Pełny tekst źródłaStreszczenie:
Abstract Degradation of raw water quality promoted the introduction of GAC (granular activated carbon) filtration and ozonation into Korean drinking water treatment facilities in 1994 in order to cope with organic pollutants. This study focuses on the evaluation of organics reduction performance of the GAC filtration with regenerated carbons using long-term operational data. Three drinking water treatment facilities at Busan were selected for this purpose. It was found in this study that GAC filtration and ozonation helped these facilities to reduce the treated levels of DOC (dissolve organic carbon) as well as of 1,4-dioxane. Regeneration affected organics reduction performance of GAC filtration. The GAC filtration with regenerated carbons was found more effective for DOC reduction, while the filtration with virgin carbons was more effective for THM (trihalomethane) reduction. These results were related to the pore size change that occurred after the regeneration. The regeneration increased the meso pore volume but decreased the micro pore volume. The regeneration cycle was important for the decrease in the micro pore volume. The micro pore volume remained relatively unchanged after the first regeneration but was substantially decreased after the regeneration was repeated by more than second time.
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"Mathematical Modelling of Material Removal Rate and Diameter of Overcut for Sodalime glass through Pressurized Flow ECDM Process by Response Surface Methodology". International Journal of Engineering and Advanced Technology 8, nr 5S3 (14.09.2019): 372–75. http://dx.doi.org/10.35940/ijeat.e1079.0785s319.
Pełny tekst źródłaStreszczenie:
The effect of electrolyte concentration, voltage, duty factor and electrolyte flow rate on material removal rate (MRR) and diameter of overcut (DOC) of the micro-hole machining of sodalime has been studied. The experimental values changed with the theoretical calculation in the range of 3 – 10 %. This mathematical model showed that decreasing electrolytic concentration reduces MRR and DOC. Pressurized flow Electrochemical Discharge Machining (pf-ECDM) can meet these differences. In order to put this phenomenon to use many experiments were experimented to machine holes on glass. Since parameters like electrolyte concentration, voltage, duty factor and electrolyte flow rate play an important role in MRR and DOC it needs to be calculated in order to improve the capability of this technology in machining difficult and high aspect ratio features. A mathematical model has been extensively developed to know the role of electrolyte concentration, voltage, duty factor and electrolyte flow in MRR and DOC of the process. However, machining excessive component ratio elements on ceramics like glass stays an ambitious challenge due to overcut. Although, electrical discharge machining (EDM) and electrochemical machining (ECM) are properly set up non-traditional strategies to meet these challenges, they are restrained to electrically conductive materials. In order to execute functionalities like excessive power and sustainability with minimal use of space, the raw substances used need to possess desirable mechanical, chemical and physical properties. Experimental research has been conducted, and the model was proven below various machining parameters. Demand for miniaturized merchandise is ever growing as they accomplish the venture of supplying the preferred functionalities with high efficiency using minimalistic raw material. These researches proved that growing the voltage in pf-ECDM plays a primary function in growing the MRR of the machined features.
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Wang, Haoli, i Pengwei Wang. "An Experimental Investigation of the Permeability in Porous Chip Formed by Micropost Arrays Based on Microparticle Image Velocimetry and Micromanometer Measurements". Journal of Fluids Engineering 139, nr 2 (7.12.2016). http://dx.doi.org/10.1115/1.4034753.
Pełny tekst źródłaStreszczenie:
Measurements of velocity and pressure differences for flows in porous chip fabricated with micropost arrays arranged in square pattern were implemented by using micro-particle image velocimetry (micro-PIV) and high precision micromanometer. Based on the measurement results, the permeability was solved by Brinkman equation under the averaged velocities over the cross section, two-dimensional velocities on the center plane of the microchannels, and the averaged velocities on the center plane considering the effect of depth of correlation (DOC), respectively. The experimental results indicate that the nondimensional permeability based on different velocities satisfies the Kozeny–Carman (KC) equation. The Kozeny factor is taken as 40 for the averaged velocity over the cross section and 15 for two kinds of center velocities based on the micropost array of this study, respectively. The permeability calculated by the velocities on the center plane is greater than that by the averaged velocity over the cross section.