The utilization of landfill-mined-soil-like-fractions (LFMSF), which is a major fraction resulting from landfill mining (LFM) activity, is being debated owing to a lack of comprehensive understanding ...of its characteristics. In this context, based on the physicochemical properties of LFMSF, several of the earlier researchers have opposed its utilization as compost, feedstock in waste-to-energy, and fill material in civil engineering applications. However, it has been noticed that LFMSF consists of required amount of organic matter (OM) and inorganic carbon (IC) to make it suitable as a buffering material that would help to modify/treat geomaterials exhibiting extreme pH values. In this context, determination of its buffering capacity (BC), a parameter that quantifies the buffering potential, becomes essential. However, determination of BC by resorting to the existing protocols is not suggestible mainly due to (i) an extremely narrow range of the pH (3–8) employed, (ii) lack of incorporation of the optimal time required for reaction/pH stabilization (tpHS), (iii) concern for decomposition of OM during the addition of H+/OH− while experimentation and (iv) heterogeneity associated with the LFMSF unlike the geomaterials that are commonly tested (viz., agricultural soils and compost). Hence, to overcome these limitations, a comprehensive methodology that can be employed for determining the ultimate buffering capacity (BCu) by establishing appropriate tpHS (i.e., 200 h) and liquid to solid ratio (i.e., 20), which would eliminate the decomposition of OM over a broad range of pH (i.e., 2–12) has been proposed. Based on the testing of several LFMSF samples collected from unscientifically created landfills/dumpsites and engineered landfills in India, easy-to-use relationships between the (i) reaction time (t) and (ii) physicochemical properties of the samples that influence BC and BCu, directly or indirectly, have also been proposed.
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•A novel methodology was developed for the determination of BC of the LFMSF.•The study considered a wide range (2.00–12.00) of pH for the determination of BCu.•The time required for pH stabilization and Liquid to solid ratio for BC determination of LFMSF samples were determined.•Models based on pH stabilization time and physicochemical properties were proposed for the determination of BCu.
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Grey water contains organic matter that is directly disposed to the environment without any treatment previously, will cause pollution and impacting life in the water. Treatment that can be done is ...using microorganisms. One of its kind is the microalgae Chlorella sp. which utilizes organic matter as a source of nutrients for its growth. In this study, the Kaldness 1 (K1) bio carrier was added as a medium for attaching microorganisms using the Sequencing Batch Biofilm Reactor (SBBR) process. The research objectives were (1) to know the maximum number of Chlorella sp. both attached and suspended in the Sequencing Batch Biofilm Reactor (SBBR), (2) to obtain the best cycle time and stabilization time in the removal of COD, Ammonia, and MLSS in grey water. The research was conducted by varying the stabilization time (1.5; 2 and 2.5 hours) in each cycle for four cycles with a constant variation of charging time 30 minutes, reaction 120 minutes, 45 minutes, separation 45 minutes, and carried out with four cycles, stirring speed at 60 rpm, the concentration of algae suspension in SBBR was 25% and the volume of Kaldness K1 medium was 20%. The results showed the number of microalgae cells Chlorella sp. was suspended and attached to 1.85 x 106 and 1.46 x 106 cells/ml. The best removal of COD, ammonia, and MLSS was found in the stabilization time variation of 1.5 hours in 4 cycles with a removal efficiency of 84% and 76%, respectively, and an increase in the concentration of suspended and attached MLSS by 4780 mg/l and 4720 mg/l. It can be concluded that the faster stabilization time, the more removal efficient will be.
In this paper, we present the last work we collaborated with our late friend, Professor Ajoy Kumar Datta (1958-2019), who prematurely left us four years ago. This article is therefore dedicated to ...him.
In this work, we shed new light on a self-stabilizing wave algorithm proposed by Colette Johnen in 1997 1. Starting from an arbitrary configuration, this algorithm endlessly re-constructs a BFS spanning tree in any connected rooted network. Nowadays, it is still the best existing self-stabilizing BFS spanning tree construction in terms of memory requirement, i.e., it only requires Θ(1) bits per edge.
However, it has been originally proven assuming a weakly fair daemon. Moreover, its stabilization time was unknown until now.
Here, we study the slightly modified version of this algorithm, still keeping the same memory requirement. We prove the self-stabilization of this variant under the distributed unfair daemon and show a stabilization time in O(D⋅n2) rounds, where D is the network diameter and n the number of processes.
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Unlike qualitative properties such as correctness (safety and liveness), quantitative properties of distributed algorithms have only been certified in very few studies. This work is the first attempt ...to certify time complexity bounds of a fault-tolerant distributed algorithm. Our case study consists in formally proving, using the Coq proof assistant, the time complexity of the first Dijkstra's self-stabilizing token ring algorithm. In more detail, we formally prove both the self-stabilization and exact worst-case stabilization time of this algorithm assuming asynchronous settings. This latter result is obtained in two main steps. First, we certify a non-trivial upper bound on the stabilization time, i.e., every execution in an N-size ring contains at most 3⋅N⋅(N−1)2−N−1 steps if N≥4, at most 3 steps if N=3; and in remaining cases, the stabilization time is zero. Then, for each case, we exhibit a possible execution whose complexity exactly matches those upper bounds. Notice that the tight bounds for N=3 and N≥4 were unknown until now, even among self-stabilization researchers.
•This work is the first attempt to certify the time complexity of a fault-tolerant distributed algorithm.•The case study consists in the worst case stabilization time in steps of the first self-stabilizing algorithm proposed by Dijkstra.•The complexity analysis is complete: we certify the exact worst case stabilization time in steps of the algorithm.
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In China, the growing amount of digestate from anaerobic digestion produced by animal husbandry is an emerging challenge. A common treatment used to eliminate this digestate is long-term ...stabilization ponds. However, this process can lead to a shortage of digestate storage space and loss of nitrogen nutrients within the digestate. To alleviate those shortcomings, this study developed an efficient stabilization pond using biochar and persulfate (BC/PS treatment). Using this treatment, the germination index (GI) of the digestate increased from 56% to 85% and the stabilization efficiency increased nearly 2.7 times. In addition, the dehydrogenase activity (DHA) in the BC/PS treatment remained between 0.47 and 0.91 μg/(g·h) across the 40 days, which indicated that BC/PS had a positive effect on microbial inactivation. In the traditional stabilization process (CK treatment), dissolved organic nitrogen (DON) decreased from 47.77 mg/L to 0.81 mg/L and ammonium nitrogen almost disappeared. The BC/PS treatment led to the promotion of nitrogen nutrient composition. Particulate total nitrogen (21.49% of total nitrogen) decomposed into dissolved total nitrogen and the DON increased from 47.77 to 58.89 mg/L. The BC/PS treatment showed a faster stabilization time, good microbial inactivation, lower toxicity, and stable nitrogen nutrient composition of the digestate compared to traditional methods.
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•BC/PS treatment can improve digestate seed germination index from 56% to 85%.•BC/PS treatment can shorten stabilization time from 30 days to 11 days.•BC/PS treatment can transform particulate total nitrogen into soluble nitrogen.•BC/PS treatment can maintain dissolved organic nitrogen and ammonia nitrogen.
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•Boom stability was evaluated in a field sprayer with a secondary blower system,•A self-designed cable measurement system was used in the experiment,•The boom’s stability states were ...described with a fuzzy logic model,•An experimental track with an obstacle was used in the experiment,•Boom stabilization time decreased with an increase in the sprayer's speed.
During the application of plant protection products (PPP), the segments of a field sprayer's boom can be displaced from equilibrium, which can lead to uneven delivery of the sprayed liquid. Modern field sprayers are equipped with stabilization systems to eliminate this problem. However, these systems do not always operate correctly in all phases of a field sprayer's motion. Therefore, the aim of this study was to determine the influence of the speed at which a field sprayer crosses an obstacle on the displacement of the boom’s terminal segments and the time after which the boom is stabilized. The experimental setup involved a field sprayer unit composed of a Claas AXOS 330 tractor and a mobile test bench – a detachable field sprayer with an air-assisted system and a boom with a working width of 21 m, which was equipped with a system for measuring boom displacement from equilibrium in two perpendicular planes. The boom's stability states were analyzed with the use of a fuzzy logic model developed by the authors. The measurements were performed in an experimental track with an obstacle. The displacement of boom tips in the horizontal and the vertical plane was registered during the experiment to determine boom stability. The experiment revealed that boom tips were displaced from equilibrium not only when the sprayer crossed the obstacle, but also when the tractor's front and rear wheels came into contact with the obstacle. Boom displacement was much greater in the horizontal than the vertical plane, and boom stabilization time was approximately three times longer in the horizontal than the vertical plane. The activation or deactivation of the air-assisted system had no significant effect on boom stability, but an increase in the sprayer's speed (from 4 to 12 km h−1) increased the time of unstable boom operation by around 50 %, decreased the time of semi-stable boom operation by around 34 %, and decreased boom stabilization time by around 45 %.
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Although postural control measures were reported to identify neuromuscular impairments, postural steadiness and stabilization time were not carefully investigated between subjects with and without ...recurrent low back pain (LBP).
Research QuestionAre there group differences in the stabilization time, direction of sway, and dynamic postural steadiness index (DPSI) during one-leg standing?
Thirty-four control subjects and 29 subjects with recurrent LBP participated in the study. Each subject stood upright on a single leg with and without visual input. The outcomes were measured for standing duration (sec), direction of sway, and the DPSI, which included the vertical steadiness index (VSI). The VSI assesses fluctuations to standardize the vertical ground reaction forces on the force plate.
The control group demonstrated significantly longer standing duration compared to the LBP group during the eyes-open condition (t = 3.55, p = 0.001). The LBP group demonstrated significantly faster stabilization time (t = 2.53, p = 0.01) in the sagittal plane. The DPSI demonstrated an excellent relationship with the VSI without visual input in the control group (r = 0.98, p = 0.001). The directions of sway demonstrated a significant interaction between groups (F = 9.29, p = 0.004).
Although standing duration in the eyes-open condition decreased in the LBP group, a faster stabilization time in the sagittal plane was evident compared to the control group to adapt postural stability. These results indicated that vertical dynamic steadiness with visual input might be important to enhance compensatory postural control.
•The low back pain group demonstrated faster stabilization in the sagittal plane.•The groups demonstrated a significant interaction with sway directions.•Vertical standing steadiness was enhanced with a longer standing duration.
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8.
Time-Optimal Leader Election in Population Protocols Sudo, Yuichi; Ooshita, Fukuhito; Izumi, Taisuke ...
IEEE transactions on parallel and distributed systems,
2020-Nov.-1, 2020-11-1, Volume:
31, Issue:
11
Journal Article
Peer reviewed
Open access
In this article, we present the first leader election protocol in the population protocol model that stabilizes within <inline-formula><tex-math notation="LaTeX">O(\log n)</tex-math> ...<mml:math><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mo form="prefix">log</mml:mo><mml:mi>n</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq1-2991771.gif"/> </inline-formula> parallel time in expectation with <inline-formula><tex-math notation="LaTeX">O(\log n)</tex-math> <mml:math><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mo form="prefix">log</mml:mo><mml:mi>n</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq2-2991771.gif"/> </inline-formula> states per agent, where <inline-formula><tex-math notation="LaTeX">n</tex-math> <mml:math><mml:mi>n</mml:mi></mml:math><inline-graphic xlink:href="sudo-ieq3-2991771.gif"/> </inline-formula> is the number of agents. Given a rough knowledge <inline-formula><tex-math notation="LaTeX">m</tex-math> <mml:math><mml:mi>m</mml:mi></mml:math><inline-graphic xlink:href="sudo-ieq4-2991771.gif"/> </inline-formula> of <inline-formula><tex-math notation="LaTeX">\mathrm{lg}\; n</tex-math> <mml:math><mml:mrow><mml:mi> lg </mml:mi><mml:mspace width="0.277778em"/><mml:mi>n</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq5-2991771.gif"/> </inline-formula> such that <inline-formula><tex-math notation="LaTeX">m \geq \mathrm{lg}\; n</tex-math> <mml:math><mml:mrow><mml:mi>m</mml:mi><mml:mo>≥</mml:mo><mml:mi> lg </mml:mi><mml:mspace width="0.277778em"/><mml:mi>n</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq6-2991771.gif"/> </inline-formula> and <inline-formula><tex-math notation="LaTeX">m=O(\log n)</tex-math> <mml:math><mml:mrow><mml:mi>m</mml:mi><mml:mo>=</mml:mo><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mo form="prefix">log</mml:mo><mml:mi>n</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq7-2991771.gif"/> </inline-formula>, the proposed protocol guarantees that exactly one leader is elected and the unique leader is kept forever thereafter. This protocol is time-optimal because it was recently proven that any leader election protocol requires <inline-formula><tex-math notation="LaTeX">\Omega (\log n)</tex-math> <mml:math><mml:mrow><mml:mi>Ω</mml:mi><mml:mo>(</mml:mo><mml:mo form="prefix">log</mml:mo><mml:mi>n</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="sudo-ieq8-2991771.gif"/> </inline-formula> parallel time.
This work presents an acoustic analog front-end based on a delta sigma-modulated sample and average common-mode feedback technique. The proposed feedback offers a process and temperature stable high ...pass (HP) frequency corner, unity dc feedback gain, and a programmable HP frequency corner to reduce startup time. In addition, this article also presents an automatic saturation detection and recovery technique from in-band input artifacts. The proposed technique was implemented in the low-noise amplifier (LNA) and programmable gain amplifier (PGA) of an acoustic analog front-end fabricated in 180-nm CMOS. The technique achieved a maximum effective resistance of 100 <inline-formula> <tex-math notation="LaTeX">\text{T}\Omega </tex-math></inline-formula>. The HP frequency corner variation across temperature and process was reduced by <inline-formula> <tex-math notation="LaTeX">226\times </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">4.38\times </tex-math></inline-formula>, respectively, compared to a traditional pseudo-resistor feedback structure. Integrated noise in the 20 Hz-4 kHz speech signal band is reduced by <inline-formula> <tex-math notation="LaTeX">2.98\times </tex-math></inline-formula> using the lowest possible HP frequency corner. The amplifier recovery time from saturation due to artifacts was reduced by <inline-formula> <tex-math notation="LaTeX">10\times </tex-math></inline-formula>. The total power consumption of the LNA, PGA, and analog to digital converter (ADC) in the acoustic front-end was 192 nW.
•A dynamic model of a single-stage absorption heat transformer using LiBr/H2O as the working pair is established.•A novel method and operation strategy are proposed to improve dynamic performance of ...an absorption heat transformer.•The improved method can eliminate more than 80% of impact caused by external water fluctuations.•The stabilization time of improved system can be reduced by 43.8%, and improved system has 1–5% higher COP.
Recently, waste heat recovery in industry applications of absorption heat transformers has developed rapidly. Due to the instability of the heat source and constantly changing heat load, it is difficult to adjust and control an absorption heat transformer to meet the needs of heat supply and heat consumption. Thus, the dynamic performance caused by thermal inertia and solution concentration inertia becomes increasingly important. A dynamic model of a vertical falling-film absorption heat transformer using LiBr/H2O as the working pair is established in this paper and validated by experimental data. The simulation results show that there is a contradiction at different stages of equipment operation. Less solution reserved in the system is more advantageous during start-up and load changing, but reserving less solution is opposite under internal and external fluctuations. Thus, a system improvement method and operational strategy are proposed to resolve this contradiction. The improved system has a faster temperature stabilization speed and higher total Coefficient of performance (COP) under start-up, load changing, and operating condition fluctuations. The stabilization time for start-up and load changing processes can be reduced by 43.8%, and a 20 kW absorption heat transformer can save about 212.2 kJ for each load changing operation.
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