Maximum Utilization Rate Research Articles

Growable Genetic Algorithm with Heuristic-based Local Search for multi-dimensional resources scheduling of cloud computing

Multi-Dimensional Resources Scheduling Problem (MDRSP, usually a multi-objective optimization problem) has attracted focus in the management of large-scale cloud computing systems as the collaborative operation of various devices in the cloud affects resource utilization and energy consumption. Effective management of the cloud requires a higher performance method to solve MDRSP. Considering the complex coupling between multi-dimensional resources and focusing on virtual machines allocation, we propose GGA-HLSA-RW (GHW, a novel family of genetic algorithms) to optimize the utilization and energy consumption of the cloud. In GGA-HLSA-RW, we add a growth stage to the genetic algorithm and construct a Growable Genetic Algorithm (GGA) using the Heuristic-based Local Search Algorithm (HLSA) with Random multi-Weights (RW) as the growth route. Based on the GHW, we propose GHW-NSGA II and GHW-MOEA/D by applying the sorting strategies and population regeneration mechanism of NSGA II and MOEA/D. To evaluate the performance of GHW, we carry out extensive experiments on the simulation dataset and AzureTraceforPacking2020 for the problems of minimizing the maximum utilization rate of resources for each dimension and minimizing total energy consumption. Experiment results demonstrate the advantages of growth strategy and dimensionality reduction strategy of GHW, as well as validate the applicability and optimality of GHW in realistic cloud computing. The experiments also demonstrate our proposed GHW-NSGA II and GHW-MOEA/D have better convergence rates and optimality than state-of-the-art NSGA II and MOEA/D.

Thermal Regulation Performance of Shape-Stabilized-Phase-Change-Material-Based Prefabricated Wall for Green Grain Storage.

In order to meet the great demand for green grain storage and low carbon emissions, paraffin, high-density polyethylene (HDPE), and expanded graphite (EG) were used to produce shape-stabilized phase change material (SSPCM) plates, which were then used to reconstruct building walls for existing granaries. A new type of SSPCM plate was then prefabricated with different thermal conductivities and a high latent heat. This plate could be directly adhered to the existing granary walls. In order to evaluate the thermal regulation performance of these phase change granary walls, experiments and numerical methods were established, specifically for the summer condition. The thermal behavior of the SSPCM granary wall was compared with that of the common concrete granary wall to obtain the optimal parameters. It was concluded that increasing the thickness of the SSPCM layer can reduce the temperature rise of the wall. However, the maximum latent heat utilization rate and energy storage effects were obtained when the SSPCM thickness was at an intermediate level of 30 mm. The thermal conductivity of the SSPCM had a controversial effect on the thermal resistance and latent heat utilization behaviors of the SSPCM. Considering the temperature level and energy saving rate, a 30 mm thick SSPCM plate with a thermal conductivity of 0.2 W/m·K provided a superior performance. When compared to the common wall, the optimized energy-saving rate was greatly enhanced by 35.83% for the SSPCM granary wall with a thickness of 30 mm and a thermal conductivity of 0.2 W/m·K.

Single-atom nanozymes: classification, regulation strategy, and safety concerns.

Nanozymes, nanomaterials possessing enzymatic activity, have been studied extensively by researchers. However, their complex composition, low density of active sites, and inadequate substrate selectivity have hindered the maturation and widespread acceptance of nanozymes. Single-atom nanozymes (SAzymes) with atomically dispersed active sites are leading the field of catalysis due to their exceptional performance. The maximum utilization rate of atoms, low cost, well-defined coordination structure, and active sites are the most prominent advantages of SAzymes that researchers favor. This review systematically categorizes SAzymes based on their support type and describes their specific applications. Additionally, we discuss regulation strategies for SAzyme activity and provide a comprehensive summary of biosafety challenges associated with these enzymes.

Melting lithium alloying to improve the affinity of Cu foil for ultra-thin lithium metal anode.

Before lithium (Li) metal can be formally used as the anode material of Li-ion battery, the key technical defects of Li metal electrode, such as low active Li metal proportion and low mechanical strength, must be solved. Herein, the surface affinity of molten lithium-copper (LiCu) alloy with Cu foil is improved by alloying Cu and Li in a molten state. The surface of Cu foil naturally adsorbs an ultra-thin (∼30μm) composite Li metal layer. The ultra-thin composite Li metal layer can greatly reduce the amount of inactive Li, and the Cu foil improves the mechanical strength and engineering workability of Li metal anode. In addition, the enhanced Young's modulus facilitates the uniform Li plating/stripping process. As a result, the stable cycle stability of up to 600h and the average overpotential of 13mV (area specific capacity is 1 mAh cm-2 and current density is 1mAcm-2) are achieved. The cycle life is higher than 150h even though the maximum utilization rate of Li is greater than 50%. The Li metal full battery assembled with the commercial NCM811 cathode shows more stable cycle performance and Coulombic efficiency. Such strategy can effectively pave the way for the practical application of Li metal anode.

Response-time analysis of mesh-based many-core systems

Scheduling models can be used to evaluate whether a particular system is able to meet its timing constrains. In many-core processors, with tens to hundreds of processors in the same chip, the analysis of the timing behavior needs to include the communications network used to exchange messages between the different processors. This paper presents a schedulability model for many-core systems based on a 2D mesh network-on-chip and store-and-forward switching with a limitation on the maximum link utilization rate that makes the analysis tractable. The model has been applied to the Epiphany many-core processor which has 16 cores connected by a 4 × 4 2D mesh. The analysis results have been tested on the real hardware by executing examples with synthetic task workloads. Those tasks are executed in a micro-kernel RTOS that we have developed. We also describe synchronization mechanisms to send messages between the tasks, and we analyze their timing behavior, so that they can be included in the analysis model.

Potential of biological sulphur recovery from thiosulphate by haloalkaliphilic Thioalkalivibrio denitrificans

ABSTRACT The aim of this study was to investigate the potential for elemental sulphur recovery from sulphurous solutions under aerobic and anoxic conditions by haloalkalophilic Thioalkalivibrio denitrificans at 0.8–19.6 g S2O3 2−-S L−1 and 0.2–0.58 g NO2 L−1, respectively. The experiments were conducted as batch assays with haloalkaline (pH 10 and ≥ 14 g Na+ L−1) thiosulphate solution. Aerobically, the highest biotransformation rate of thiosulphate obtained was 0.03 h−1 at 8.5 g L S2O3 2−-S. Based on Monod model, the maximum substrate utilisation rate (qm) was 0.024 h−1 with half saturation constant (Ks) 0.42 g S2O3 2−-S L−1 at initial [S2O3 2--S] of 14 g L−1. S0 accumulated at [S2O3 2−-S] ≥ 1.5 g L−1 (10% yield at initial 9.5 g S2O3 2−-S L−1) and the highest S0 yield estimated with the model was 61% with initial [S2O3 2--S] of 16.5 g L−1. Anoxically, the maximum nitrite removal rate based on Monod modelling was 0.011 h−1 with Ks = 0.84 g NO2 − L−1. Aerobically and anoxically the maximum specific growth rates (µm) were 0.046 and 0.022 h−1, respectively. In summary, high-rate aerobic biotransformation kinetics of thiosulphate were demonstrated, whereas the rates were slower and no S0 accumulated under anoxic conditions. Thus, future developments of biotechnical applications for the recovery of S0 from haloalkaline streams from the process industry should focus on aerobic treatment. Highlights Haloalkaline S2O3 2− biotransformations kinetics by Thioalkalivibrio denitrificans Aerobic thiosulphate-S bioconversion up to 0.024 h−1 with Ks = 0.42 g S2O3 2−-S L−1 10% S0 yield with initial 9.5 g S2O3 2--S L−1 in aerobic condition Anoxic NO2 removal up to 0.01 h−1 with Ks = 0.84 g NO2 − L−1

Optimization of Railway Mixed Goods Loading Layout considering Stability.

It is well known that stability, center-of-gravity balance, and concentrated-weight are key factors of the transportation safety. The reasonable formulation of the loading layout scheme ensures the safety of shipment based on fully utilizing the effective volume and load capacity of freight vehicles. This paper takes the railway mixed goods loading layout as the research object, considering the constraints such as goods loading center-of-gravity balance, the allowable moment of concentrated-weight, supporting and goods placement mode, and taking the maximum comprehensive utilization rates for both effective volume and load capacity of freight vehicle as the optimization objective, an optimization model of railway mixed goods balanced and anticoncentrated-weight loading layout considering stability is built. Additionally, this paper designs mixed goods classified and simple/general goods block composition methods. We improve the representation and selection of layout space, construct goods block selection algorithm based on the greedy d-step lookahead tree search and goods block evaluation function and propose a goods block placement strategy and update rules of layout space after goods block placement. An optimization algorithm of railway mixed goods balanced and anticoncentrated-weight load layout considering stability is designed. The results show that the formulated scheme not only ensures that the goods meet the full support constraints, but also the comprehensive utilization rate of the effective volume and load capacity of the vehicle is not less than 89%, and the probability of meeting the loading center-of-gravity balance and allowable moment of concentrated-weight are as high as 99% and 99.47%, respectively. The proposed method realizes the balanced and anticoncentrated-weight loading of railway mixed goods, ensures the safe, stable, and efficient goods loading, and provides decision support for the safe loading layout of railway goods.

AQUACULTURE IN TURKEY

The world's resources dedicated to fisheries and aquaculture are predicted to remain stable at their maximum utilization rate. Many intensive fish farms with recirculation production systems are needed in order to achieve sustainable output. Combined or integrated production projects are needed for sustainable production and to meet the high demand for food supplies. However, due to a substantial migration problem from rural areas to metropolitan centers, labor may be a concern in the aquaculture business. Turkey is still improving technology in order to maximize resource utilization while minimizing disruption to aquatic systems. With the growth of aquaculture, some environmental issues have been identified. Based on the present study, it was predicted that Tukey will produce 700,000 tons of fish by 2050. The purpose of this paper is to provide an overview of the current situation, as well as studies on sustainability and future developments in the field.

O-067 Artificial intelligence system detects “goldilocks” morphokinetic zone for embryos transferred or frozen in time-lapse videos

Abstract Study question Are there specific morphokinetic time points which can be used to determine whether an embryo should be discarded? Summary answer Morphokinetic ranges where embryos will be discarded rather than transferred or cryopreserved, can be defined using time-lapse annotations automatically generated with artificial intelligence (AI). What is known already Time-lapse incubation has changed the way embryos are selected. Instead of static daily observations, continuous monitoring of embryos allows for generation of morphokinetic parameters which quantify the pace of development. However, annotations by humans have been shown to incur operator variations and are time-consuming to perform. AI can automatically annotate embryos with equivalence in accuracy to experienced embryologists. Although most embryo selection methods are designed to identify the embryo with the highest chance of becoming a healthy live birth baby, the ability to identify embryos that will not be suitable for treatment is equally important for clinical decision making. Study design, size, duration This is a prospective, observational, cohort study. Time-lapse videos from 142 embryos from a private fertility clinic in Spain were automatically annotated using CHLOE (Fairtility), an AI-based software. CHLOE automatically generated the following morphokinetic parameters: tPNa, tPNf, t2, t3, t4, t5, t6, t7, t8, t9+, tM, tSB, tB, tEB. Participants/materials, setting, methods Embryos analysed were from donor and own oocyte’s treatments. Selected embryos were analysed using CHLOE, to automatically identify morphokinetic parameters. The distribution for each morphokinetic parameter was compared between fates (data presented for transferred + frozen vs discarded as mean+-standard deviation, 2-sided t-test). Each continuous morphokinetic parameter was categorised according to the ranges where embryo utilisation was futile (<1%), optimal (maximum utilisation rate) or reduced utilisation rate (between optimal and futile). Main results and the role of chance For every morphokinetic parameter the difference in event time between frozen+transferred vs discarded embryos was statistically significant(p < 0.003). The results detail the time point in hours for each morphokinetic feature to occur (mean(SD) frozen+transferred vs discarded, p-value): tPNa (7.68(2.03)vs22.04(27.15),p<0.0001), tPNf (21.71(2.86)vs34.63(24.11),p<0.0001), t2 (24.92(2.71)vs33.78(16.17),p<0.0001), t3 (34.62(4.03)vs42.58(22),p=0.0024), t4 (37.29(4.31)vs48.29(20.29,p<0.0001), t5 (47.03(6.47)vs55.32(22.63),p=0029), t6 (49.54(5.63)vs60.56(22.20),p<0.0001), t7 (53.1(7.86)vs69.13(24.54),p<0.0001), t8 (57.78(9.78)vs77.33(25.79),p<0.0001), t9+ (69.14(7.39)vs81.9(21.96),p<0.0001), tM (83.9(8.72)vs96.08(16.88),p<0.0001), tSB (97.89(7.55)vs105.38(11.38),p=0.0005), tB (105.74(7)vs113.25(15.53),p=0.0002), eEB (110.65(7.58)vs120.47(11.36),p=0.0031). When looking at the exact distribution of these embryos according to time, it became apparent that a goldilocks zone appeared whereby the proportion of embryos transferred or frozen peaked, and the number discarded was at its minimum. The converse was true when looking at the more extreme values of a particular parameter. Thus, we were able to determine the (optimal vs futile time ranges): tPNa (4.4-8.8 hours, where the utilization rate was at its maximum vs < 4.4 or > 13.7, where the utilization rate was at its minimum), tPNf (19.1-23.2vs<9.4,>28.9), t2 (23.-36.4vs<19.9,>33.6), t3 (32.1-37.4vs>24.6,>43), t4 (34-40.2vs<29.5,>55), t5 (42.7-52vs<33.7, >63.5), t6 (45-4-54.2vs<36.10,>63.70), t7 (47.8-56.7vs<42.8,>77.5), t8 (49.2-64.5 vs <44.5,>82.5), t9+ (64.1-74.2vs<57,>90), tM (76.6-92.6 vs <64.7,>104.2), tSB (91.2-105vs<81.3,>113.8), tB(97.2-111.2 vs <92,>118.7), tEB (103.4-116.7,<94.7,>122.5). A 60% of the embryos were in the futile range in at least 1 parameter, from which only 1 in 3 were utilised. Limitations, reasons for caution This is a single centre study. Further work will (i) test the limits across different clinics, with different geographical demographic variations, and varied clinical practices, to understand how these factors affect the limits between futile and optimal ranges of morphokinetics, and (ii) assess clinical outputs (implantation, ploidy, live birth). Wider implications of the findings Identifying objective ranges for determining when an embryo is not suitable for treatment will help reduce variation between and within embryologists and clinics; will avoid overly optimistic decisions which waste time and resources and increase patient’s emotional burden, and increase professional confidence when selecting embryos for discarding, transfer or freezing Trial registration number not applicable

Relationship of particle size, reaction and sticking behavior of iron ore fines toward efficient fluidized bed reduction

The relationship of particle size, reaction and sticking behavior of iron ore fines toward efficient fluidized bed hydrogen reduction were systematically investigated at 600–800 °C in a laboratory fluidized bed. First, the reduction kinetics were studied, and the results showed that hydrogen reduction of granulated iron ore was controlled by reduction reaction, and the activation energy was approximately 88.4 kJ/mol. The reduction rate of granulated iron ore with a diameter of 200 μm could be increased by 10 times as the reduction temperature rose from 600 to 800 °C. Then, a modified force balance model was established to distinguish the critical sticking point of granulated iron ore during high temperature fluidized bed hydrogen reduction, and it indicated that the defluidization temperature could be raised from 630 to 790 °C as the particle size was enlarged from 100 to 200 μm with a fluidization number of 10. Eventually, coupling the kinetic model and modified force balance model, the maximum gas utilization rate of fluidized bed hydrogen reduction was estimated, and it indicated that at reduction temperatures of 650–750 °C with particle sizes of 200–300 μm, the optimal gas utilization rate could be achieved, which was consistent with the experimental results. Contradictory to traditional understandings of chemical reaction engineering, due to the interaction of reduction performance and sticking behavior, too high of a reduction temperature or too small of a particle size might not be preferable for fluidized bed hydrogen reduction, and this study provided valuable references for industrial operation.

SMA: SRv6-Based Multidomain Integrated Architecture for Industrial Internet

With the increasing requirements of industrial production efficiency, the Industrial Internet has played a very important role in the fourth industrial revolution. However, the current Industrial Internet still has many drawbacks, especially in terms of network systems, such as low network expansion, inconvenient troubleshooting, and low data transmission efficiency. For this motivation, a novel SRv6-based multidomain integrated architecture (SMA) for the Industrial Internet has been proposed. Multilayer controllers are deployed in the SMA, and a software-defined network controller that generates the transmission path is replaced by SMA nodes, which realizes the high network scalability and efficient data transmission of the Industrial Internet. The faulty node in the SMA can be quickly and accurately identified through the periodic detection actively sent by the controller node in the domain and the passive feedback of the SMA nodes, and the generated SMA node trusted set (SNTS) can be used for forwarding path generation. A Bellman–Ford algorithm with a hop count constraint based on the total number of SNTS nodes is proposed, which effectively avoids long-path forwarding and improves network resource utilization. Through theoretical analysis, the safety and scalability of the SMA have been fully verified. The simulation results of the SMA on the experimental platform show that the SMA is superior to the existing Industrial Internet network structure in terms of troubleshooting efficiency of faulty nodes, network throughput, and data communication overhead. In the Industrial Internet, when the proportion of SMA nodes reaches 30%, the SMA controller can control nearly 80% of the traffic. In addition, the maximum link utilization rate will be greatly reduced, which means better adjustment of network load balance.

Spatial and temporal patterns of electric vehicle charging station utilization: a nationwide case study of Switzerland

Abstract The expansion of the public charging infrastructure for electric vehicles is seen as central to the development of electric mobility in many countries. Although national studies of charging infrastructure utilization based on real-world data would be a sound basis for demand planning, such studies are scarce. Using Switzerland as an example, this study examines the spatial and temporal patterns of charging infrastructure utilization. To this end, detailed, nationwide, real-time utilization data from 3086 electric vehicle supply equipment units (EVSEs) at electric vehicle charging stations were collected over a period of several months and analyzed exploratively and statistically. The maximum average utilization rate of the EVSEs surveyed during the study period is between 14% and 16%, depending on the day of the week and time of day. Most charging occurs Monday through Friday during peak working hours and on Saturday during the day. The median utilization time is higher in the largest cities than the statewide average. Charging stations along major transit routes do not have higher utilization rates than in other locations. The results suggest that public charging infrastructure is used primarily in cities and agglomeration during work hours. The findings from this study may help plan and make better use of funding to expand charging infrastructure.

Morphological, kinetic, and microbial community characterization of anammox bacteria with different inoculations and biofilm types for low-ammonium wastewater treatment

Granular anammox sludge treating high-ammonium wastewater and biofilm anammox sludge treating low-ammonium wastewater were inoculated in two identical reactors to treat low-ammonium wastewater. The morphological and microbial community characterizations were investigated. Kinetic models were applied to understand kinetic characterizations and predict reactor performances. Both types of sludge adapted well in 10 and 5 days with the average total inorganic nitrogen removal efficiencies >85%. The average particle size of the granular sludge decreased from 843 μm to 515 μm. The biomass and thickness of the biofilm sludge increased by 17% and 66% when NH4+-N, NO2−-N and temperature increased from 10 mg/L to 33 mg/L, <0.5 mg/L to 41 mg/L, and circa 13 °C to 35 °C, respectively. The granular sludge had higher maximum utilization rate constant and saturation value constant (16.393 and 12.934 mg/(L·h)) than biofilm sludge (1.017 and 0.080 mg/(L·h)), indicating the inherent difference of inoculations. The granular sludge inoculated from high nitrogen loading rate (NLR) (0.36 g-N/(g-VSS·d)) condition had the potential to withstand a higher NLR than that in present reactor (0.14 g-N/(g-VSS·d)). The results of Grau second-order model indicated that both reactors performed good nitrogen removal efficiency despite inoculations and types differences, and can predict the nitrogen removal efficiency well. Microbial community diversities deceased, but granular bacteria richness increased due to the lower free ammonium and free nitrous acid. The dominant anammox bacteria in the granular sludge shifted from Candidatus Kuenenia to Candidatus Brocadia. Candidatus Kuenenia was always the dominant anammox bacteria in the biofilm sludge.

MODEL SURPLUS PRODUKSI PENGELOLAAN IKAN TERI DI PERAIRAN SUNGAI APIT KABUPATEN SIAK PROVINSI RIAU

Anchovies (Stolephorus sp), need to be managed well because although as a natural resource that is open access if not managed properly, the management of fishery resources is not optimal and sustainable. One approach in the management of fish resources is with a surplus production model. The analysis was conducted to obtain the best model that aims to know the maximum sustainable catch (MSY), utilization rate, and use of anchovies. Data on catches and anchovies fishing efforts were collected from the Siak District Fisheries and Livestock Service. The best Surplus Production Model used to assess the potential of anchovies is the Walter-Hilborn model. Optimal effort (EMSY) of 150 Units per year. Cmsy's optimal catch is 247.75 tons per year. The utilization rate for 2020 is 70%, with an entrepreneurial rate of 41%, which indicates that overfishing has not occurred both biologically and economically.

Parallel Optimisation and Implementation of a Real-Time Back Projection (BP) Algorithm for SAR Based on FPGA.

This study conducts an in-depth evaluation of imaging algorithms and software and hardware architectures to meet the capability requirements of real-time image acquisition systems, such as spaceborne and airborne synthetic aperture radar (SAR) systems. By analysing the principles and models of SAR imaging, this research creatively puts forward the fully parallel processing architecture for the back projection (BP) algorithm based on Field-Programmable Gate Array (FPGA). The processing time consumption has significant advantages compared with existing methods. This article describes the BP imaging algorithm, which stands out with its high processing accuracy and two-dimensional decoupling of distance and azimuth, and analyses the algorithmic flow, operation, and storage requirements. The algorithm is divided into five core operations: range pulse compression, upsampling, oblique distance calculation, data reading, and phase accumulation. The architecture and optimisation of the algorithm are presented, and the optimisation methods are described in detail from the perspective of algorithm flow, fixed-point operation, parallel processing, and distributed storage. Next, the maximum resource utilisation rate of the hardware platform in this study is found to be more than 80%, the system power consumption is 21.073 W, and the processing time efficiency is better than designs with other FPGA, DSP, GPU, and CPU. Finally, the correctness of the processing results is verified using actual data. The experimental results showed that 1.1 s were required to generate an image with a size of 900 × 900 pixels at a 200 MHz clock rate. This technology can solve the multi-mode, multi-resolution, and multi-geometry signal processing problems in an integrated manner, thus laying a foundation for the development of a new, high-performance, SAR system for real-time imaging processing.

Analysis of Energy Consumption and Its Influencing Factors in Hydrogen Metallurgy Process

Hydrogen metallurgy is an effective way for the high carbon emission steel industry to achieve low‐carbon green transformation and upgrading. According to energy conservation law, the article establishes gas utilization rate and thermal balance calculation models, discusses the influence of key factors such as reducing gas composition, reducing the temperature, and metallization rate on the gas utilization rate and energy consumption, and theoretically calculates the change of energy consumption in the process of steel industry production caused by using hydrogen. The optimal reduction temperature range is 1250–1350 K, which has theoretical minimum energy consumption, about 3.14 GJ, and maximum gas utilization rate, about 45%. The results show that when using 100% hydrogen reduction, increasing the reduction temperature properly lower theoretical energy consumption can be achieved and raise gas utilization rate and further achieve the goal of energy saving and consumption reduction, which is expected to provide beneficial help for hydrogen metallurgy developing in the steel industry.

Aerodynamic performance analysis and power generation characteristics experiment of vertical axis wind turbine

AbstractWith the wide application of clean energy, the requirements of this vertical axis wind turbine are higher and higher. A new diagonal spiral blade vertical axis wind turbine is designed and studied. The shape of the new type of wind turbine blade is designed based on the diagonal spiral structure that is common in life, considering the situation of different pitch angles and constructing 11 kinds of prototype machine. In‐depth analysis of the aerodynamic performance of these new wind turbines through simulation calculations shows that the prototype with a pitch angle of 110° has the best aerodynamic performance. When the tip speed ratio is 0.4, the maximum wind energy utilization rate can reach 0.29. Besides, the model of this wind turbine is constructed by 3D printing, which is tested, and the performance of the models is compared with that of the traditional S‐type wind turbine in a real environment. There rationality and superiority of the design of the new diagonal spiral blade vertical axis wind turbine are proved, and this apply background of this new diagonal spiral blade wind turbine is demonstrated by comparison. This article also analyzes the wake of the wind turbine and makes reasonable planning of the arrangement spacing that the wake effect has the least effect on the downstream wind turbine, which can increase the power generation efficiency of the group arrangement of turbines.

Study on the utilization of non-mechanical ventilation power in extra-long highway tunnels with shafts

The conventional design of tunnels includes the low utilization rate of non-mechanical ventilation power, and is not suitable for the ventilation design of extra-long highway tunnels. The main purpose of this paper is to study the allowance of the non-mechanical wind pressure in each part of an extra-long highway tunnel with shafts, and to propose a tunnel ventilation method with a higher utilization rate of the non-mechanical wind pressure. Based on the ventilation network, the loop division method of a common shaft ventilation tunnel is first established, and the pressure modules in the tunnel are calculated. Then, each module is input into the ventilation network model, the non-mechanical wind pressure margin of each loop is calculated, and the distribution method of the required air volume is adjusted to ensure that the non-mechanical wind pressure margin is reasonable. Finally, according to the distribution results, the tunnel fan can be configured, and the shaft resistance can be adjusted if necessary to ensure the maximum utilization rate of non-mechanical ventilation power in the tunnel. According to the design results of the Funiushan tunnel in China, the energy-saving effect of this method is evident, which verifies its rationality.

Substrate diversity affects carbon utilization rate and threshold concentration for uptake by natural bacterioplankton communities

Persistence of dissolved organic matter (DOM) in aquatic environments may in part be explained by high diversity and low concentrations of carbon substrates. However, changes in dissolved substrate quality can modify aquatic bacterial community composition and rate of carbon uptake. The aim of this study was to test if the presence of multiple simple substrates affects the turnover of organic carbon. Natural bacterial communities were grown in continuous cultures supplied with either individual carbon substrates—salicylic acid (SA), tryptophan (Trp) or tyrosine (Tyr)—or a combination of the 3 substrates. Concentrations were tracked using fluorescence spectroscopy, and steady-state concentrations of a few nanomolar were reached. Bacterial growth efficiency was dependent on which carbon sources were present and reached an intermediate level in the combined treatment. The bacterial community maintained steady-state concentrations of Trp that were lower in the combined treatment than in the individual substrate treatment. In addition, steady-state concentrations were reached faster during growth on combined carbon substrates, although the maximum utilization rate of each individual compound was lower. However, the steady-state concentration of total carbon (sum of carbon content of SA, Trp and Tyr) was higher in the combined culture than in the individual substrate treatments, and seemed to be determined by the carbon substate for which the bacteria had the lowest affinity. The results from this study indicate that persistence of dissolved organic carbon can in part be explained by vast substrate diversity, which raises the threshold concentration for utilization by natural bacterial communities.

Structural optimal design and power generation characteristics of a bionic type nautilus vertical axis wind turbine

Nautilus vertical axis wind turbine is a new breed which is being designed and developed through bionics and geometry, this kind of wind turbine is not only novel in appearance, and stable in structure, but also has excellent aerodynamic performance. Based on this type of wind turbine, combined with its structural characteristics, this paper designed 20 prototypes by continuously adjusting the structural parameters of the spiral blades. The performance of these prototypes is compared by simulation, the optimal structure of this kind of wind turbine is selected. This optimized wind turbine has a strong ability to collect wind energy and can obtain higher wind energy utilization in a wider range of wind speed, the maximum wind energy utilization rate reaches 32.842%. Then the wake characteristics are analysed, the reasonable arrangement is designed. This paper also built an equal scale reduced version of the real object using a 3D printer, and assembles it with a small disc type electric machine to construct a vertical axis wind power generation apparatus. Finally, experiments are conducted in a real environment to analyse the rotational speed and voltage waveform of this apparatus under different operating conditions experimentally.