Spring Rate Research Articles

Incidence and molecular characterization of fungi and yeast isolated from cultured catfish and Nile tilapia

Objective: To study the incidence and seasonal dynamics of different fungi affected freshwater fishes in Lake Manzala with molecular identification of the isolated fungi. Animals: 300 Nile tilapia (Oreochromis niloticus) and 300 catfish (Clarias gariepinus). Design: Descriptive study. Procedures: Random samples of Oreochromis niloticus (O. niloticus) and Clarias gariepinus (C. gariepinus) were collected from Manzala fish farms. Clinical and postmortem examination of fish was applied. Isolation and identification of different fungi were performed by conventional methods. Furthermore, the molecular characterization of isolated fungi was carried out. Results: C. gariepinus had a higher rate of infection with different fungal species than O. niloticus. Aspergillus spp. (Aspergillus niger and Aspergillus flavus) were the most fungal isolated from the examined fishes, followed by Penicillium spp. and Candida albicans. Aspergillus spp were detected in all seasons with a higher rate in summer and spring. A. flavus, A. niger, Penicillium spp. and C.albicans isolates were amplified from both C. gariepinus and O. niloticus at the specified molecular weight using PCR. Conclusion and clinical relevance: Fungal infection affected the fish showing different external and internal lesions, all species of Aspergillus were found in all seasons with a high rate in, hot seasons, summer and spring. The Prevalence of Penicillium and C. albicans were also reported. All fungal isolates were identified on the phenotypic and molecular bases.

Design Methodology of Centrifugal Automatic Decompression System in Small Gasoline Engine

<div class="section abstract"><div class="htmlview paragraph">This paper deals with designing methodology of centrifugal type automatic decompression system (CADS) for small gasoline engine. CADS reduce the operator’s fatigue to start the engine. When engine cranked, CADS releases combustion pressure of the engine via opening of exhaust valve momentarily during compression stroke, which drastically reduces the hand pulling force required to start the engine with recoil starter unit. A 172 cc gasoline engine, which has applications in agricultural purposes, has been used for designing and development of CADS, which has to be installed at camshaft cam gear assembly of engine. With the new developed concept operator’s hand pulling force for starting the engine has been reduced to 41 % and henceforth durability of engine starting system increased significantly. In this paper detailed design approach has been discussed of working model of CADS. Based on predicted failure modes and generated RPN values, design calculations were carried out for various geometrical parameters of sub parts of CADS like mass of centrifugal flyweight, number of coils, wire diameter, spring rate of torsion spring. PTC CREO 3.0 has been used to make rough 3 D model of assembly and further it is optimized based on calculated design values and ease of manufacturability. A testing approach also has been discussed for checking desired spring rate of torsion spring and on engine overall working mechanism of CADS.</div></div>

Denitrification in urban river sediment and the contribution to total nitrogen reduction

Streams and rivers, especially in urban areas, are substantial sinks of bioavailable nitrogen owing to their hydrological connections with terrestrial systems and the intensity of inputs mediated by human activities. Denitrification can account for nitrogen removal in rivers, but its importance in urban rivers has been scarcely studied. This study chose 8 representative rivers in Shanghai, under different level of urbanization, and measured denitrification rates of sediments across a year. The results showed significant differences in temporal, spatial and vertical distributions (p < 0.05). Seasonally, the denitrification rate in spring and winter were lower than in autumn. Spatially, the higher denitrification rate of rivers in residential and industrial areas than that in suburban rivers, which dominated with cultivated land, was weakly related to dissolved oxygen (DO) (p < 0.05, r = −0.380) and ammonium nitrogen (NH4+-N) concentration (p < 0.05, r = 0.303) in the water column. Vertically, the surface layer (0–2 cm) accounted for 78.2% of the total denitrification capacity (0–5 cm). The denitrification rates among different depths positively correlated with the extractable nitrate concentration (SNO3−-N), the extractable ammonium nitrogen concentration (SNH4+-N), the organic carbon concentration (SOC), water content and pH of sediment to varying degrees. In addition, the mean annual denitrification rate of studied rivers was calculated as 2.62 ± 0.420 mg N m−2 h−1, and denitrification contributed nearly 20% of the nitrogen removal, these results underscore the importance of denitrification in nitrogen reduction of urban rivers.

Incidence and molecular characterization of fungi and yeast isolated from cultured catfish and Nile tilapia.

Objective: To study the incidence and seasonal dynamics of different fungi affecting freshwater fishes in Lake Manzala as well as molecular identification of the isolated fungi. Animals: 300 Nile tilapia (Oreochromis niloticus) and 300 catfish (Clarias gariepinus). Design: Descriptive study. Procedures: Random samples of Oreochromis niloticus (O. niloticus) and Clarias gariepinus (C. gariepinus) were collected from Manzala fish farms. Clinical and postmortem examination of fish was applied. Isolation and identification of different fungi were performed by conventional methods.Furthermore, the molecular characterization of isolated fungi was carried out. Results: C. gariepinus had a higher rate of infection with different fungal species than O. niloticus. Aspergillus spp. (Aspergillus niger and Aspergillus flavus) were the most fungal isolated from the examined fishes, followed by Penicillium spp. and Candida albicans. Aspergillus spp were detected in all seasons with a higher rate in summer and spring. A. flavus, A. niger, Penicillium spp . and C.albicans isolates were amplified from both C. gariepinus and O. niloticus at the specified molecular weight using PCR. Conclusion and clinical relevance: Fungal infection affected the fish showing different external and internal lesions, all species of Aspergillus were found in all seasons with a high rate in, hot seasons, summer and spring. The Prevalence of Penicillium and C. albicans were also reported. All fungal isolates were identified on the phenotypic and molecular bases.

Analysis and predication of tuberculosis registration rates in Henan Province, China: an exponential smoothing model study

BackgroundThe World Health Organization End TB Strategy meant that compared with 2015 baseline, the reduction in pulmonary tuberculosis (PTB) incidence should be 20 and 50% in 2020 and 2025, respectively. The case number of PTB in China accounted for 9% of the global total in 2018, which ranked the second high in the world. From 2007 to 2019, 854 672 active PTB cases were registered and treated in Henan Province, China. This study was to assess whether the WHO milestones could be achieved in Henan Province.MethodsThe active PTB numbers in Henan Province from 2007 to 2019, registered in Chinese Tuberculosis Information Management System were analyzed to predict the active PTB registration rates in 2020 and 2025, which is conductive to early response measures to ensure the achievement of the WHO milestones. The time series model was created by monthly active PTB registration rates from 2007 to 2016, and the optimal model was verified by data from 2017 to 2019. The Ljung-Box Q statistic was used to evaluate the model. The statistically significant level is α = 0.05. Monthly active PTB registration rates and 95% confidence interval (CI) from 2020 to 2025 were predicted.ResultsHigh active PTB registration rates in March, April, May and June showed the seasonal variations. The exponential smoothing winter’s multiplication model was selected as the best-fitting model. The predicted values were approximately consistent with the observed ones from 2017 to 2019. The annual active PTB registration rates were predicted as 49.1 (95% CI: 36.2–62.0) per 100 000 population and 34.4 (95% CI: 18.6–50.2) per 100 000 population in 2020 and 2025, respectively. Compared with the active PTB registration rate in 2015, the reduction will reach 23.7% (95% CI, 3.2–44.1%) and 46.8% (95% CI, 21.4–72.1%) in 2020 and 2025, respectively.ConclusionsThe high active PTB registration rates in spring and early summer indicate that high risk of tuberculosis infection in late autumn and winter in Henan Province. Without regard to the CI, the first milestone of WHO End TB Strategy in 2020 will be achieved. However, the second milestone in 2025 will not be easily achieved unless there are early response measures in Henan Province, China.

Spatial variability in macrofaunal diet composition and grazing pressure on microphytobenthos in intertidal areas

AbstractMicrophytobenthos forms an important part of the diet of macrofauna (macrozoobenthos) in many intertidal ecosystems. It is unclear, however, whether the dependence of macrofauna on microphytobenthos varies spatially within and among tidal systems. We aim (1) to assess the spatial variability in the importance of microphytobenthos in the diet of macrofauna (i.e., between and within two tidal basins and as function of elevation), (2) to quantify grazing pressure of the macrofaunal community on different potential food sources (microphytobenthos, phytoplankton and terrestrial organic material) for several sites in two tidal basins and (3) to compare microphytobenthic production and summer/autumn grazing of the total macrofaunal community and grazing pressure per feeding type, with potential microphytobenthic production estimated from rates in early spring, when grazing was low. Using a natural stable isotope approach, we identified microphytobenthos as a more important food source for macrofauna than phytoplankton and terrestrial organic material. Microphytobenthos dependency differed between tidal basins for the genera Bathyporeia (sand digger shrimp), Macoma (Baltic tellin), and Peringia (mudsnail) and for sampled individuals of all genera combined, and did not vary as function of elevation. We showed that macrofaunal grazing on microphytobenthos is quantitatively important and, in some cases, approached microphytobenthic production rates in early spring. No positive relation between microphytobenthic production in early spring and macrofaunal grazing in summer/autumn was observed. This suggests that the studied consumer‐resource interactions are coupled on a larger spatial scale (i.e., mesoscale, ≈10 to 100 km), rather than the fine (mm to m) scale.

A sensitive SYBR Green RT-qPCR method for grapevine virus E and its application for virus detection in different grapevine sample types

To develop a rapid and high-sensitivity method for detection of grapevine virus E (GVE), a SYBR Green based real-time fluorescence quantitative RT-PCR method (RT-qPCR) was established. This method could be used to detect GVE specifically, and the sensitivity was about 100 times greater than conventional RT-PCR. An excellent linear correlation (R2=0.997) and a high amplification efficiency (E=97.5%) were obtained from the standard curve of this method. Reproducibility tests revealed that the coefficients of variation in the intra- and inter-assay results were 0.31–1.03% and 0.82–2.62%, respectively, indicating a good reproducibility. The RT-qPCR method could be used to detect GVE in a wide range of grapevine sample types. The detection rates of RT-qPCR for nearly all sample types from different positions and seasons were higher than conventional RT-PCR. The detection rates in spring, summer, autumn and winter increased gradually. Samples in autumn and winter were best for detection, and the detection rates of most samples were 80–100%, which were 10 to 40% higher than conventional RT-PCR. In general, old petioles and branches were the best tissues for GVE detection. The detection rates of these samples in each season were all 100%, which were 20 to 40% higher than conventional RT-PCR. The second highest rates were in the old leaf, with detection rates for RT-qPCR of 80–100% in all seasons, which were 20 to 40% higher than conventional RT-PCR. GVE could be difficultly detected in young leaves by conventional RT-PCR, and the detection rates were only 0–50%, while by RT-qPCR the rates could increase to 0–80%. A total of 33 out of 363 samples (belonging to 68 cultivars) from 20 regions in China were detected to be positive by RT-qPCR (9.1%), which was more than twice the rate of the conventional RT-PCR (3.9%).

Analysis on the Characteristics of Temperature Change in Zhengzhou from 1990 to 2017

In order to find out the changing trend of temperature and extreme weather in Zhengzhou under the background of rising global temperature. This study analyzes the changing trend of annual mean temperature and seasonal average temperature in Zhengzhou from 1990 to 2017 based on meteorological data. The extreme temperature index for 28 years was extracted. The results show that from 1990 to 2017, the air temperature in Zhengzhou shows a significant upward trend, and its rising rate is higher than that of the global warming rate. There are differences in the four seasons in Zhengzhou, with the largest change rate in spring, followed by summer and autumn, and the weakest warming trend in winter. The extreme temperature index in Zhengzhou has certain regularity, the extreme index FD0 decreases significantly, the change of ID0 is not obvious, and SU25, TR20 and HTD35 increase significantly. Except for the change of IDO is not obvious, other indexes can better reflect the warming trend of temperature in Zhengzhou, indicating that the extreme temperature index has an obvious response to the change of temperature and can be used as an index to study the change of urban temperature.

Forecasting the resilience of Bibitarkhoun karst spring, southwest Iran, to the future climate change

Even though the “resilience” term has been widely employed in ecology and somewhat in surface water hydrology, vis-a-vis groundwater, it has been hitherto scarcely utilized. In this study, firstly, the climatic variables of Lali region, southwest Iran, and the discharge rates of a substantial karst spring, i.e. Bibitarkhoun, were obtained in the base (1961–1990) and future (2021–2050) time periods under two Representative Concentration Pathways (RCPs), i.e. RCP4.5 and RCP8.5, utilizing NASA Earth Exchange Global Daily Downscaled Projections data set and artificial neural networks, respectively. Secondly, the spring’s dynamic storages were quantified by depicting its loss curves over the years of the base and future time periods. Thirdly, the Groundwater Resilience Index (GRI) was computed based on the Standardized Precipitation Index approach, using the spring’s discharge rates (GRI1) and dynamic storages (GRI2). The spring’s loss curve corresponds to no-precipitation period, and it was taken into account as the disturbance event to assess the spring’s resilience. Results demonstrated that if the GRI values less than − 1.5, i.e. very and extremely dry years, were taken into account as the disturbance events, the satisfactory condition would be achieved immediately in the next year. Therefore, a promising resilience is expected under climate change. The spring’s loss curves of the observation data indicated it takes approximately three and 5 years to exceed the threshold of 60 and 80% reduction in the spring’s discharge rates, respectively.

Benthic fluxes of dissolved oxygen and nutrients across hydrogeomorphic zones in a coastal deltaic floodplain within the Mississippi River delta plain

We tested the hypothesis that benthic fluxes will increase spatially in a coastal deltaic floodplain as sediment organic matter increases in response to developing hydrogeomorphic zones along a chronosequence of the active Mississippi River Delta. A continuous flow-through core system was used to incubate intact sediment cores from three hydrogeomorphic zones along a chronosequence in the emerging Wax Lake Delta (WLD). Organic matter content increased from younger to older deltaic sediments from subtidal to supratidal hydrogeomorphic zones, which were coupled with increasing benthic oxygen and nitrogen fluxes. Mean net denitrification rate in spring was 100 µmol N2–N m−2 h−1 with significantly lower rates occurring in the younger intertidal zones (T4 transect, − 22 µmol N2–N m−2 h−1) and higher rates occurring in the older supratidal zones (T2 and T1 transects, 330 and 262 µmol N2–N m−2 h−1, respectively). Mean net denitrification rate in summer was 397 µmol N2–N m−2 h−1 without significant site-to-site variability except for the supratidal-T2 site (911 µmol N2–N m−2 h−1) showing higher denitrification rate than the other sites. Based on seasonal temperature and inundation time, annual rates of benthic NO3− removal varied from − 0.5 to − 3.4 mol m−2 y−1 and N2–N production rates varied from 1.0 to 3.2 mol N m−2 y−1 across WLD. The subtidal zone had the lowest fluxes associated with lower organic matter content, but was the hydrogeomorphic zone with the largest area and longest flood duration, and therefore contributed over half of N removal in WLD. The estimated annual NO3− removal of 896 Mg N y−1 in WLD accounts for 10 to 27% of total NO3− load to WLD, most of which is converted to N2 through denitrification. As a small prograding coastal deltaic floodplain under early stages of delta development, WLD is a continuously emerging ecosystem where the capacity of N removal increases by 0.2 to 2% per year prior to riverine NO3− is export to coastal ocean. These results highlight the contribution of the coastal deltaic floodplain in an active coastal basin in processing elevated riverine NO3− at continental margins with coastal ocean. The potential loss of this ecosystem service in N removal may increase in global significance as delta areas decline as result of accelerated relative sea level rise and decreased sediment loading in major river basins around the world.

Model optimization and economic analysis of a multi-effect diffusion solar distiller

This study focused on finding the maximum productivity by optimizing vertical multi-effect diffusion solar distiller (VMED) and lowering the water cost of that. The numerical model of the VMED was experimentally validated, and then used to find the optimal conditions for the essential variables. The VMED consists of a glass cover, plates, wicks, and a seawater feeding unit. Each effect has a cotton-cloth wick attached to one side of the plate. This VMED repeatedly using condensation latent heat can get more production than that of conventional solar still. The numerical result showed that the optimum values of the gap distance of double glass cover and the number of effects were 25–30 mm and 10–15, and the feed flow rates of spring, summer, fall, and winter were optimal in 9, 16, 10, and 3 g/min, respectively in supplying same flow rate into all the effects. The maximum productions for all seasons (spring, summer, fall, and winter) were 16.6, 36.0, 19.0, 2.5 kg/(m2·d), respectively in South Korea. Economic analysis showed that the potential water price of the VMED was 6.1 $/m3, which was more competitive in the market than other solar desalination systems with a small capacity of <100 m3/d.

Analytical modeling of axial oscillation-supported drillstrings in high-angle wells

Downhole vibrations generated from axial oscillation tools (AOTs) in axial oscillation-supported drillstrings (AOSDs) has become one of the efficient means of reducing friction and improving weight transfer during sliding operations in horizontal and extended-reach wells. Dynamic modeling of AOT-excited drillstrings is needed for validating the functionality of axial oscillation tools during surface tests and predicting their response under downhole conditions.An analytical model is presented in this study to predict the behavior of axial oscillation-supported drillstrings working under downhole and surface conditions. The model is useful to perform parametric studies, downhole data correlation and placement study of AOTs along the drillstring in horizontal and extended-reach wells. Unlike existing models, the nonlinear equation of motion is derived from a model damped in a viscous medium with Coulomb friction and subjected to displacement excitation. The model also accounts for the spring rate of the axial oscillation tool. The displacement excitation is obtained from the spring rate, which is a critical input to the model. The nonlinear damping is approximated with an equivalent viscous damping coefficient to obtain an analytical solution. The developed model in this study is validated with published experimental measurements obtained from field-scale drillstrings.Correlations between predicted and measured axial displacement and accelerations at different excitation frequencies, pressure drops and spring rates show an approximate average deviation of 14.5%. Also, results from this study strongly accentuates that flow rate is the most critical operating parameter for axial oscillation tools because it affects the amplitude of pressure drop, excitation force, and operating frequency of AOTs.

Seasonal variations in sperm DNA fragmentation and pregnancy rates obtained after artificial insemination with cooled-stored stallion sperm throughout the breeding season (spring and summer)

The aim of this study was to assess seasonal variations during different periods of the breeding season (spring and summer) on stallion sperm DNA fragmentation and in vivo fertility associated with cooled-stored semen samples. Ejaculates were collected from eleven stallions and assessed for sperm motility (assessed by computer-assisted sperm analysis) and plasma membrane integrity (evaluated under fluorescence microscopy). Sperm DNA fragmentation (evaluated by the Sperm Chromatin Dispersion test) was assessed in cooled-stored semen at 5 °C for up to 24 h. Artificial insemination was performed throughout the breeding season. Mares were inseminated with cooled-stored semen (up to 24 h) every other day until ovulation. Pregnancy rates per cycle were determined detecting the embryonic vesicle by ultrasonography fifteen days after ovulation. Values (mean ± SD) for progressive sperm motility were significantly higher (P < 0.05) in spring (53.57 ± 9.97%) in comparison to summer (41.37 ± 10.81%). No significant differences in plasma membrane integrity were found between seasons (P > 0.05). Sperm DNA fragmentation was significantly lower (P < 0.01) in spring in comparison to summer after 0h (4.81 ± 1.87% vs. 8.77 ± 5.78%), 6h (9.00 ± 3.19% vs. 18.73 ± 8.22%) and 24h (14.6 ± 4.13% vs. 30.14 ± 9.85%) of cooled-storage. Pregnancy rates per cycle were also significantly higher (P < 0.01) in spring (50%) in comparison to summer (37%). There was a moderate negative relationship between positive pregnancies and sperm with fragmented DNA (r = - 0.619; P < 0.001). Semen samples associated with moderate fertility levels (Pregnancy rate < 50%) showed a higher percentage of sperm with fragmented DNA compared to samples obtaining higher fertility levels. In conclusion, seasonal variations were found during the breeding season, obtaining lower sperm DNA fragmentation and higher pregnancy rates in spring. Additionally, samples with the highest proportion of sperm with fragmented DNA showed the lowest fertility levels throughout the breeding season.

Evaluation of fluopyram for the control of Ditylenchus dipsaci in sugar beet.

Fluopyram, a succinate dehydrogenase inhibitor fungicide, has shown potential in controlling Meloidogyne incognita and Rotylenchus reniformis in tomato. The effectiveness of this compound for the control of Ditylenchus dipsaci in sugar beet was evaluated. In this study, laboratory, growth chamber, glasshouse, and field experiments were conducted. In a motility bioassay, the EC50 value was determined with 3.00 μg/ml a.i. after 72 h exposure to fluopyram. The growth chamber experiment did not show any effects on D. dipsaci penetration rate; however, field experiments revealed a positive effect of fluopyram applied at planting in reducing D. dipsaci infectivity. The glasshouse experiment confirmed a limited effect of fluopyram on D. dipsaci population development. Under field conditions, despite a reduction of D. dipsaci penetration rates in spring, fluopyram was not effective in reducing the population development until harvest. Consequently, D. dipsaci densities in plant tissue and soil were high at harvest and not different among treatments. However, root-rot symptoms were significantly reduced at harvest. Fluopyram applied at planting showed good potential to reduce root-rot symptoms caused by D. dipsaci in sugar beet. However, for the long-term reduction of nematode populations in soil, further integrated control measures are needed to reduce the risks of substantial yield losses by D. dipsaci.

I-nteract: A Cyber-Physical System for Real-Time Interaction With Physical and Virtual Objects Using Mixed Reality Technologies for Additive Manufacturing

This paper presents I-nteract, a cyber-physical system that enables real-time interaction with real and virtual objects in a mixed reality environment to design 3D models for additive manufacturing. The system has been developed using mixed reality technologies such as HoloLens, for augmenting visual feedback, and haptic gloves, for augmenting haptic force feedback. The efficacy of the system has been demonstrated by generating a 3D model using a novel scanning method to 3D print a customized orthopedic cast for human arm, by estimating spring rates of compression springs, and by simulating interaction with a virtual spring in a mixed reality environment.

Seasonal Variations of Arctic Low-Level Clouds and Its Linkage to Sea Ice Seasonal Variations.

Using CALIPSO‐CloudSat‐Clouds and the Earth's Radiant Energy System‐Moderate Resolution Imaging Spectrometer data set, this study documents the seasonal variation of sea ice, cloud, and atmospheric properties in the Arctic (70°N–82°N) for 2007–2010. A surface‐type stratification—consisting Permanent Ocean, Land, Permanent Ice, and Transient Sea Ice—is used to investigate the influence of surface type on low‐level Arctic cloud liquid water path (LWP) seasonality. The results show significant variations in the Arctic low‐level cloud LWP by surface type linked to differences in thermodynamic state. Subdividing the Transient Ice region (seasonal sea ice zone) by melt/freeze season onset dates reveals a complex influence of sea ice variations on low cloud LWP seasonality. We find that lower tropospheric stability is the primary factor affecting the seasonality of cloud LWP. Our results suggest that variations in sea ice melt/freeze onset have a significant influence on the seasonality of low‐level cloud LWP by modulating the lower tropospheric thermal structure and not by modifying the surface evaporation rate in late spring and midsummer. We find no significant dependence of the May low‐level cloud LWP peak on the melt/freeze onset dates, whereas and September/October low‐level cloud LWP maximum shifts later in the season for earlier melt/later freeze onset regions. The Arctic low cloud LWP seasonality is controlled by several surface‐atmosphere interaction processes; the importance of each varies seasonally due to the thermodynamic properties of sea ice. Our results demonstrate that when analyzing Arctic cloud‐sea ice interactions, a seasonal perspective is critical.

Optimization of a mono-composite leaf spring using a hybrid fiber-layup approach

Conventional leaf springs are simple in design, utilizing multiple metallic bars (leaves) with low geometrical moment of inertia to generate an economical and linear spring rate. In its early form, the leaf-spring was manufactured using metals like steel, but, in modern applications, there exist composite leaves reinforced by advance glass and carbon fibers. Benefits of composite spring designs include: high specific strength, ability to form complex profiles, and possibility of subcomponent consolidation to reduce assembly. Due to the bending characteristics of the leaf spring, the axial load decreases through the beam thickness, reaching a minimum at the neutral surface. Given this fact, a design optimization approach for mono-composite leaf springs is developed considering a hybrid fiber-layup. Initially, a detailed topology optimization is conducted to optimize the geometry of the leaf spring based on the Tsai-Wu failure model. This process yielded a unique spring design which reduced the mass of the spring by 29% compared to the initial non-optimized spring and 80–90% compared to a steel spring. Subsequently, the design is further optimized by replacing low stress, high modulus reinforcement with lower modulus and cost-effective materials to improve overall vehicle mass, efficiency, and operation. The second stage of the optimization based on the hybrid fiber-layup approach resulted in an additional 7% mass reduction. As there is a connection between fuel efficiency and vehicle mass, the significant reduction of spring mass has a positive impact on vehicle fuel consumption and leads to suspension responsiveness gains. Moreover, the possibility of swapping up to 20% of the middle plies reinforcement with commodity plastics demonstrates the cost benefits of the hybrid fiber-layup design approach considering the high cost of carbon and other high-performance reinforcements.

Contrasting Spring and Summer Large-Scale Environments Associated with Mesoscale Convective Systems over the U.S. Great Plains

AbstractMesoscale convective systems (MCSs) are frequently observed over the U.S. Great Plains during boreal spring and summer. Here, four types of synoptically favorable environments for spring MCSs and two types each of synoptically favorable and unfavorable environments for summer MCSs are identified using self-organizing maps (SOMs) with inputs from observational data. During spring, frontal systems providing a lifting mechanism and an enhanced Great Plains low-level jet (GPLLJ) providing anomalous moisture are important features identified by SOM analysis for creating favorable dynamical and thermodynamic environments for MCS development. During summer, the composite MCS environment shows small positive convective available potential energy (CAPE) and convective inhibition (CIN) anomalies, which are in stark contrast with the large positive CAPE and negative CIN anomalies in spring. This contrast suggests that summer convection may occur even with weak large-scale dynamical and thermodynamic perturbations so MCSs may be inherently less predictable in summer. The two synoptically favorable environments identified in summer have frontal characteristics and an enhanced GPLLJ, but both shift north compared to spring. The two synoptically unfavorable environments feature enhanced upper-level ridges, but differ in the strength of the GPLLJ. In both seasons, MCS precipitation amount, area, and rate are much larger in the frontal-related MCSs than in nonfrontal MCSs. A large-scale index constructed using pattern correlation between large-scale environments and the synoptically favorable SOM types is found to be skillful for estimating MCS number, precipitation rate, and area in spring, but its explanatory power decreases significantly in summer. The low predictability of summer MCSs deserves further investigation in the future.

Assessing the Self-Purification Capacity of Surface Waters in Lake Baikal Watershed

The removal of trace metals (TM), dissolved organic carbon (DOC), mineral nitrogen (Nmin.), and polycyclic aromatic hydrocarbons (PAHs) from the water of Lake Baikal and its tributaries was evaluated. The contaminant removal rate (CRR) and the contaminant removal capacity (CRC) were used as water self-purification parameters. The CRR was calculated as the difference between contaminant mass flow rates at downstream and upstream gauging stations. The CRC was calculated as the quotient of the CRR and the change in water discharge between downstream and upstream gauging stations. Whether the CRR and CRC have positive or negative values depends on whether contaminant release or removal occurs in the water body. The CRR depends on the size of the water body. The lowest and the highest CRRs observed for Baikal were equal to −15 mg/s (PAHs) to −7327 g/s (DOC), whereas the highest PAH and DOC removal rates observed for Selenga River (the major Baikal tributary) in summer were equal to −9 mg/s and −3190 g/s correspondingly. The highest PAH and DOC removal rates observed for small tributaries were equal to 0.0004 mg/s and −0.7 g/s respectively. The amplitude of annual CRR oscillations depends on contaminant abundance. The highest amplitude was typical for most abundant contaminants such as Nmin. and DOC. In unpolluted sections of the Selenga River the highest rates of N and C removal (−85 g/s and −3190 g/s, respectively) were observed in summer and the lowest rates (4 g/s and 3869 g/s, respectively) were observed in the spring. The lowest amplitude was typical for PAHs and some low-abundance TM such as V and Ni. The highest summer rates of V and Ni removal were equal to −378 mg/s and −155 mg/s respectively, whereas lowest spring rates are equal to 296 mg/s and 220 mg/s. The intermediate CRR amplitudes were typical for most abundant TM such as Sr, Al, and Fe. The spatial CRR variability depends on water chemistry and the presence of pollution sources. The lowest (up to 38 g/s) rates of Nmin. removal was observed for polluted lower Selenga sections characterized by low water mineralization and high DOC concentrations. The highest rates (−85 g/s) were observed for unpolluted upper sections. Seepage loss from the river to groundwater was also recognized as an important means of contaminant removal. The CRC values depend mostly on water residence time. The DOC removing capacity value of Baikal (−26 g/m3) were lower than those of Selenga in summer (−35 g/m3) but higher than the CRCs of all tributaries during the other seasons (from 30 mg/m3 to −10 g/m3).

Trade-offs and synergies between seed yield, forage yield, and N-related disservices for a semi-arid perennial grassland under different nitrogen fertilization strategies

A 15N labeling and lysimeter experiment was conducted with mesocosms of a semi-arid Leymus chinensis grassland. The aim of the study was to evaluate the effects of N fertilization timing (fertilization in fall or spring) and rate (0, 56, and 112 kg-N ha−1 year−1) on ecosystem services (seed yield and forage yield), ecosystem disservices (N leaching surveyed during 1 year and emissions of NH3 and N2O integrated over 76 days after fertilization), and recovery of added fertilizer N in plants and soil. Seed and forage yields increased more under fall than spring N fertilization. Further, N fertilization was linked to higher soil NH3 and N2O emissions, particularly under high N rate for both NH3 (2.0 and 1.6 kg-N ha−1 under fall and spring N fertilization, respectively) and N2O (0.24 and 0.21 kg-N ha−1, respectively). N leaching was never observed. A significant N fertilization timing × rate interaction effect was observed on plant recovery efficiency of added fertilizer N (Plant-NRE). Plant-NRE was higher for high than moderate N rate, with + 13.2% (from 22.8 to 36%) and + 16.4% (from 28.2 to 44.7%) for fall and spring fertilization, respectively. Fertilizer N recovered in soil was highest for moderate N rate in fall (68% of total N fertilizer) and lowest for high N rate in spring (46%). Our results show synergies among the ecosystem services (seed and forage yields) and among the disservices (NH3 and N2O emissions), and trade-offs between the services and disservices, some of these synergies and trade-offs being modulated by N fertilization timing and rate. Our study is the first one analyzing the possibly interactive effects of the N fertilization timing and rate on this range of ecosystem services and disservices in semi-arid perennial grasslands, which can be useful for N risk: benefit analysis when evaluating N fertilization strategies.