Line System Research Articles

Constructing a zero leak landfill cell

Engineered landfill barriers are the last line of defence in protecting precious groundwater resources from contamination. A landfill cell without any leaks at the conclusion of construction is the exception rather than the rule. From design to materials testing to installation practices and contractor care, all of these elements contribute to both the short and long-term integrity of the lining system. Electrical leak location (ELL) methods can be used to detect leaks in installed landfill cells after construction so that leaks can be repaired before a landfill cell begins filling operations. However, the thorough testing of landfill cells using ELL can be complicated by their complex configuration. The dipole method, employed after cover material placement, requires electrical isolation of the cover material, which is difficult to achieve with a landfill expansion cell configuration. Additionally, employing only this type of testing can leave the tie-in area untested, which is a critical area prone to damage. This paper provides solutions for complete landfill expansion cell testing, including a relatively new testing methodology (ASTM D8265, [1]), which provides protocol for verifying that a geomembrane has been successfully installed with no leaks. A case study is included to show how ASTM D8265 can be used to provide documentation of a zero-leak condition of a landfill cell after construction. Common elements of design, geomembrane installation, and quality assurance are discussed in order to provide a road map of how to reach a zero-leak condition at the end of a landfill expansion cell construction project. This paper can be used as a guide to constructing a zero-leak landfill cell using state-of-the art construction practices and ELL testing methodologies.

IMPLEMENTATION OF THE KANBAN SYSTEM IN A SCREW PRODUCTION LINE: A CASE STUDY A COMPANY IN THE JOINVILLE REGION

The implementation of inventory management within a company is of fundamental importance to support strategic decision-making, such as purchases of raw materials and production volume. In view of this, the kanban supply system presents the concept of reducing inventory, avoiding high amounts invested in raw materials. The developed work aims to implement the kanban system in a production line of screws in a company in the region of Joinville. With the implementation of the kanban system, it was possible to reduce about 30% of the stock level, monitor the stock level visually, and increase production flexibility and agility in the availability of parts.

Study of the electromagnetic system of holding the mine in the barrel channel of the gas detonation mortar

The paper presents the results of the study of the electromagnetic system of holding the mine in the bore of the gas detonation mortar. To reduce the time from the detection of the target to its destruction, the use of a gas detonation mortar with a semi-automatic guidance system in the direct line of sight of the target is proposed. This type of mortar will reduce the total time of hitting the target to 2-3 minutes. An analysis of the influence of the magnetic holding of the mine on the operation of the gas detonation mortar was carried out. Holding the mine in the bore during the formation of the gaseous propellant charge allows you to fix the volume of the charge. The electromagnetic mine holding system consists of an electromagnetic coil, a magnetic circuit, a DC source with a commutator. The switch on of the electromagnetic system is carried out immediately before the shot to reduce the heating of the coil. The mine holding force was calculated, on the basis of which the parameters of the mine holding electromagnetic system were substantiated. Based on the results of experimental studies, the dependence of the holding force of the mine on the power supply current of the electromagnetic system was determined. The developed dynamometric measurement system consisted of a piezoelectric force meter with a spring, an electric cylinder and a cable clutch. The pressure when the mine detaches from the electromagnet in the barrel of the gas detonation mortar is estimated. It was found that the power consumed by the electromagnetic system is about 15 W, and with holding forces of 930-980 N, mine extraction will begin at the overpressure of the compressed gas charge, equal to 0.15-0.2 MPa.

Selection and cultivation of seaweed Kappaphycus alvarezii using a long line system (outdoor)

In outdoor cultivation at Amal Beach, three seeding mass selections were reared for 30 days for each cycle. Each variety had a different DGR %/day (Daily Growth Rate %/day) value at the end of the growing season on G1-G2-G3 ranging from 3.62-5.90 %/day, which were still categorized as good, and G3 var.Lampung had the highest DGR value. Carrageenan yield values in this study, G1 to G3, ranged from 23.16% to 45.87%, where the G3 G2 G1 treatment. The best thallus samples (20% were selected for each generation) resulted in carrageenan yield sample population in each variety, where var.Lampung var.Tarakan var.Kupang. The biplot analysis shows that the DGR variable vector coincides with the IAA, Phosphate, Gibberellin, and Ammonia vectors. Ammonia stepwise regression analysis (sigα) affects DGR with an Ammonia coefficient value of 4.89; meaning that for each increase in the Ammonia value by one unit, the estimated mean value of DGR will increase by 4.89. Thus, the application of the mass based on the results of this study was able to increase the DGR value Kappaphycus alvarezii, which in turn produce the highest yield of carrageenan with K. alvarezii var.Lampung G3 was the best seed candidate to be developed at the seaweed cultivation site in Tarakan City.Keywords:AlgaePhytohormonesCarrageenanNitrogenViscosity

Experimental Studies of a Universal Mathematical Model of Leakage Currents and Ground Currents Distribution on the Elements of HVPTL

In Kazakhstan, the main power transmission line with a line voltage of 500 kV, geographically runs through the whole of Republic from north to south. The high-voltage power line is of strategic importance. The failure of one support leads to a halt in the technological process of transporting electricity to entire regions of the country. In order to increase reliability and reduce operating costs, various modifications of diagnostics and monitoring systems for overhead power lines are being widely introduced in the CIS countries. Currently, the introduction of a complex of diagnostics of structural elements of the 500 kV HVPL has become particularly relevant, firstly, the cost of damage in accidents has increased significantly, and secondly, due to the long service life, the reliability of the power system has decreased. For the successful implementation of the diagnostic complex, an accurate representation of the processes occurring during the operation of the supports is necessary. For this purpose, a universal model of leakage currents and spreading currents along the elements of the overhead line supports was developed.

Research on the direction perception of cruising copepods by the fish lateral line using pressure difference matrix and residual neural network regression method

Autonomous Underwater Vehicles (AUVs) are high-end marine equipment. In turbid, dimly lit waters that require high concealment, traditional methods struggle to detect targets effectively. Fish, however, can accurately perceive nearby targets using lateral line systems even in harsh environments. This provides inspiration for intelligent detection in AUVs. In this study, the flow field cloud around copepods and visualization of pressure difference matrix are analyzed. A method combining the pressure difference matrix and residual neural network regression is proposed to study how fish lateral lines perceive the direction of cruising copepods. Furthermore, the effects of three key parameters on direction perception are discussed, including perception time scale, initial vertical distance and training angular intervals number. The results indicate that most predicted directions are close to the true directions, with only a small number of misjudgments occurring in the vicinity of the opposite or perpendicular directions to the true direction. Moderate perception time scales (100 ms), shorter vertical distances (2.5 mm), and reasonable training angular intervals number (24 or 36) all lead to lower perception error. This study provides a quantitative analysis of fish lateral line perception mechanism, offering valuable theoretical guidance and technical support for intelligent detection in AUVs.

Dynamics of rogue waves and modulational instability with the Manakov system in a nonlinear electric transmission line with second couplings

Dynamics of rogue waves and modulational instability with the Manakov system in a nonlinear electric transmission line with second couplings

The oral sensory organs in Bathochordaeus stygius (Tunicata Appendicularia) are unique in structure and homologous to the coronal organ

BackgroundAppendicularia consists of approximately 70 purely marine species that belong to Tunicata the probable sister taxon to Craniota. Therefore, Appendicularia plays a pivotal role for our understanding of chordate evolution. In addition, appendicularians are an important part of the epipelagic marine plankton. Nevertheless, little is known about appendicularian species, especially from deeper water.ResultsUsing µCT, scanning electron microscopy, and digital 3D-reconstruction techniques we describe three pairs of complex oral sensory organs in the mesopelagic appendicularian Bathochordaeus stygius. The oral sensory organs are situated at the anterior and lateral margin of the mouth and inside the mouth cavity. A single organ consists of 22–90 secondary receptor cells that project apical cilia through a narrow hole in the epidermis. The receptor cells are innervated by branches of the second brain nerve.ConclusionsBased on position, morphology, and innervation we suggest that the oral sensory organs are homologues of the coronal organs in other tunicates. We discuss the hypothesized homology of coronal organs and the lateral line system of primary aquatic vertebrates. The complex oral sensory organs of B. stygius are unique in tunicates and could be adaptations to the more muffled environment of the mesopelagic.

Design of Digital Control System for Line Following Robot

Design of mobile robots has become an increasingly growing trend in the technology of modern times. They are very attractive engineering systems, not only because of many interesting theoretical aspects concerning kinematics, intelligent behavior and autonomy, but also because of applicability in many human activities. A typical example is the line following robot (LFR). In order for a LFR to function effectively, it must demonstrate excellent line tracking control. This is achieved by having accurate and responsive control algorithms as well as high precision color sensor systems. This paper proposes a system to show that good line tracking performance can be achieved with moderately simple digital control algorithms. The platform used is a differentially driven wheeled robot constructed using the Lego Mindstorms components. The simulation models are presented and analyzed using MATLAB Simulink . The main programming environment is the EV3 Software.

S0 Galaxies: Outer Gas Accretion through Tidal Interaction and Minor Merging

To clarify the sources of outer gas accretion onto disk galaxies, we study the vicinity of four interacting galaxy systems in the Hα emission line by using the scanning Fabry–Perot interferometer of the 6m telescope of the Special Astrophysical Observatory RAS. We find perspective accretion flows seen as ionized-gas emission filaments between the galaxies. We discuss the whole kinematics and origin of these flows.

Civil Aircraft Passenger-to-Freighter Main Cargo Compartment lining Validation Technology

Passenger-to-freighter conversion is a common practice in the aviation industry, especially for older civil aircraft that have completed their passenger service missions. Converting these aircraft into freighters extends their operational lifespan by several years, significantly increasing the overall economic benefits throughout their life-cycle. The main cargo compartment lining is a crucial component of the P2F conversion process, It must meet the requirements outlined in CCAR-25. This paper, based on experiences in civil aircraft Passenger-to-freighter conversions, examines the CCAR-25 regulations, verification methods, and qualification criteria applicable to main cargo compartment lining systems, with a focus on important aspects of these regulations.

A Novel Lightning Overvoltage Protection Scheme Using Magnetic Rings for Transmission Line Systems

Overvoltage protection technology is critical to the safe and stable operation of power electronics equipment and power systems. In this study, based on the characteristics of lightning traveling waves, a novel lightning overvoltage protection scheme was proposed using magnetic rings (MRs) for transmission line systems (TLSs). First, the dynamic inductance of the lightning protection scheme using MRs was theoretically derived by combining the ampere loop law and the infinitesimal method. The finite element method (FEM) was then used to verify the theoretical derivation of dynamic inductance (TDDI) of the lightning protection scheme. Furthermore, the TDDI was integrated into the electromagnetic transient program, and the electromagnetic transient model (ETM) of the TLS with the lightning protection scheme was established. Subsequently, the effects of MR characteristics under the influence of various factors on the protection performance of the lightning protection scheme were investigated. Finally, the MR string in the lightning overvoltage protection scheme with optimal physical structure was used for field application. The results confirmed the feasibility of the lightning overvoltage protection scheme and ETM accuracy.

Structural and functional evolution of the mechanosensory lateral line system of fishesa).

The mechanosensory lateral line system is the flow sensing system present in all 34 000+ species of fishes. Its neuromast receptor organs, located on the skin or in bony canals on the head and tubed scales on the trunk, respond to the near field component of acoustic stimuli as well as short range, low frequency (0-200 Hz) water flows of biotic and abiotic origin. Here, I discuss the genesis of my research career and its focus on the structural and functional evolution of the lateral line system among a wide taxonomic range of fishes including those from different aquatic habitats (tropical lakes to coral reefs and the deep sea). I discuss the importance of investigating structure before function, using investigations in my laboratory that had unexpected outcomes, as well as the role of serendipity in the evolution of a career and in the nature of scientific discovery.

Metal enrichment and evolution in four z > 6.5 quasar sightlines observed with JWST/NIRSpec

We present JWST/NIRSpec R ≃ 2700 spectra of four high-redshift quasars: VDES J0020–3653 (z = 6.860), DELS J0411–0907 (z = 6.825), UHS J0439+1634 (z = 6.519), and ULAS J1342+0928 (z = 7.535). The exquisite data quality, signal-to-noise ratio of 50–200, and large 0.86 μm ≤ λ ≤ 5.5 μm spectral coverage allowed us to identify between 13 and 17 intervening and proximate metal absorption line systems in each quasar spectrum, with a total number of 61 absorption-line systems detected at 2.42 < z < 7.48 including the highest redshift intervening O Iλ1302 and Mg II systems at z = 7.37 and z = 7.44. We investigated the evolution of the metal enrichment in the epoch of re-ionisation (EoR) at z > 6 and found the following: i) a continued increase in the low-ionisation O I, C II, and Si II incidence, ii) decreasing high-ionisation C IV and Si IV incidence with a transition from predominantly high- to low-ionisation at z ≈ 6.0, and iii) a constant Mg II incidence across all redshifts. The observations support a change in the ionisation state of the intergalactic medium in the EoR rather than a change in metallicity. The abundance ratio of [Si/O] in five z > 6 absorption systems show enrichment signatures produced by low-mass Pop III pair instability supernovae, and possibly Pop III hypernovae. In the Gunn-Peterson troughs, we detected transmission spikes where Lyα photons can escape. From 22 intervening absorption line systems at z > 5.7, only a single low-ionisation system out of 13 lies within 2000 km s−1 from a spike, while four high-ionisation systems out of nine lie within ∼2000 km s−1 from a spike. Most spikes do not have associated metal absorbers close by. This confirms that star-forming galaxies responsible for producing the heavy elements that are transported to the circumgalactic medium via galaxy winds do so in predominantly high-density, neutral environments, while lower density environments are ionised without being polluted by metals at z ≈ 6 − 7.

Research on dynamic responses of mooring line system of semi-submersible platforms in Vietnam sea conditions using random model

Recently, due to the nearshore oil fields in Vietnam were nearly exhausted, oil and gas extraction proceeds to deeper water areas using the mooring floating offshore structures. Therefore, the durability of the mooring system in deep water should be studied through determining the dynamic tension of the mooring line system using random wave models. However, full stochastic dynamics analysis for mooring line system takes up a lot of time and requires large computing resources. This paper is going to study the hydrodynamic interaction of random waves onto a semi-submersible platform, thereby analysing the dynamic responses in time domain of the mooring system using the “time window” method to optimize computational time and computing resources. This method performs the dynamic simulations around the maximum quasi-dynamic tension values to determine the dynamic tension and the dynamic amplification factor (DAF) of a maximum load-bearing mooring line, thereby evaluating the dynamic responses for the whole mooring system. The method is applied to calculate for a semi-submersible platform in Dai Hung field in Vietnam Sea.

Channel Estimation in MIMO OFDM Systems with Tapped Delay Line Model

The continuous increase in the user demands fornew-generation communication systems, is making the wireless channel more complex and challenging for estimation, developing a simulation model for the channel,and evaluating the performance of different MIMO systems. In this work, a simulation model for multipath fading channels in wireless communication is performed. The model includes a selection of typical Tapped-Delay-Line channel models that can be implemented to reproduce the effects of representative channel distortion and interference. Based on the simulation results, the proposed method exhibits accurate channel estimation performance for frequency-selective fading channels. The proposed work employed LS, MMSE, and ML methods for channel estimation, using 16 and 32 pilots and fixed pilot locations in each frame. Results are obtained for 4x4, 8x8, 16x16, 16x8, and 16x4 MIMO systems and tapped delay line systems.

Assessment of fault potential and touch voltage in the low-voltage distribution line system of the residential community

Considering the increasing risk of electric shock in old residential communities, this paper investigated fault potential and consequential human-body touch voltage in the low-voltage (LV) distribution network under typical line-fault conditions by numerical simulation with a circuit approach. Three protective grounding configurations of the LV distribution system were of concern, and the electric shock scenarios considering practical situations were introduced for assessment. It has been observed that the phase-to-ground fault potential of equipment increases when the fault location is closer to the faulty equipment itself and decreases when it moves further toward the circuit end. The equipment in a building is likely exposed to the dangerous phase-to-ground fault potential under the line fault. As for line-to-neutral short circuit and neutral-line-open fault, the fault potential distribution mainly depends on the specific grounding configurations. Bonding of non-exposed steelwork in the buried building foundation to the nearby grounded grid may not be recommended in the literature, but it could effectively mitigate the touch voltage in and around the building of concern in this paper. Note that this measure, together with the local equipotential bonding method inside a flat, can provide enhanced protection against electric shock even if the protective device fails to operate or is unavailable. Among three grounding configurations, the one with multiple grounding points of the neutral wires up to the entrance of a building leads to the least dangerous touch voltage cases.

A Semi-Analytical Model of Contaminant Transport in Barrier Systems with Arbitrary Numbers of Layers

In regions with sanitary landfills, unsuitable liner designs can result in significant soil and groundwater contamination, leading to substantial environmental remediation costs. Addressing this challenge, we propose a semi-analytical model for solute transport that uses the advection–dispersion–reaction equation in a multi-layered liner system. A distinctive feature of our model is its ability to account for infiltration velocity, arbitrary numbers of layers, thin layers such as geomembranes, and mass flow. We validated our model against existing published models and applied it to a case study of a real sanitary landfill in the capital of Brazil. Through parametric analyses, we simulated contaminant transport across various layers, including the geomembrane (GM), geosynthetic clay liner (GCL), soil liner (SL), and compacted clay liner (CCL). The analyses showed the importance of choosing the most appropriate construction system based on the location and availability of materials. Considering toluene contamination, a GM molecular diffusion coefficient (DGM) greater than 10−13 m2 s−1 exhibited similar efficiency when compared with CCL (60 cm thick). In addition, the results showed that the liner system may have the same efficiency in changing SL (60 cm thick) for a GCL (1 cm thick).

Dominant causal factors of failure performance of cross-jointed segmental lining

To understand the failure behavior of segmental linings with inclined bolts, this study proposes a group of interrelated contribution-measuring scales (CMS) to evaluate the contributions and relative importance of causal factors. In the field of failure behavior research, parametric analysis is typically used to weight the sensitivity of a system to hypothetical changes in specific parameters; however, the true contribution of influencing factors to the system cannot be assessed via this sensitivity analysis. Identifying and ranking the contributions of causal factors to system effects is important for understanding as to why an incident occurs. To this end, this study first analyzes the member force breakdown structure of a crossed-jointed segmental lining, followed by the evaluation principle, evaluation indices and criteria, and analytical calculation method of the CMS. Finally, the CMS is used to analyze the failure behavior of a cross-jointed segmental lining. The results indicate that: (1) Based on the moment search method and moment separation algorithm, the CMS can be calculated analytically, and the maximum error between the analytical method and numerical solution does not exceed 3 %. (2) For the cross-jointed lining, the magnitude of the joint effect on the lining moment is related to the attenuation of the rotational stiffness of the joint and the system nonlinear characteristics are governed by the dominant joints. (3) Using the CMS, the structure and its variation in the mechanical response of the segmental lining system in the failure history can be measured and represented effectively and the governing variables can be identified quantitatively to simplify the understanding of the system failure behavior.

Sorption and diffusion of per-polyfluoroalkyl substances (PFAS) in high-density polyethylene geomembranes

The objective of this study is to investigate the fate and transport of per-polyfluoroalkyl substances (PFAS) through a high-density polyethylene (HDPE) geomembrane (GM) that is commonly used in landfill composite liner systems. Tests were conducted to measure the sorption and diffusion of per-polyfluoroalkyl substances (PFAS) with varying number of carbons in chain and functional groups on HDPE GM. Perfluoroalkyl carboxyl acids (PFCAs), perfluoroalkyl sulphonic acids (PFSAs), alkyl-sulfonamidoacetic acids (FOSAAs), fluorotelomer sulfonic acids (FtSAs), alkane sulfonamides (FOSA) and ether carboxylic acids (Gen X) were investigated in this study. The partition coefficients (Kd) on HDPE GM ranged from 3.8 to 98.3 L/kg. PFAS with amide and sulfonic functional groups showed stronger sorption than that of PFAS with carboxylic acid functional groups. Molecular weight directly affected the Kd for long-chained PFAS whereas the Kd of short-chained PFAS was not sensitive to molecular weight. The diffusion coefficients (Dg) of PFCAs and PFSAs through 0.1-mm HDPE GM were found to be in the orders of 10-18 to 10-17 m2/s. The Dg decreased with increasing molar mass and were also observed to be dependent on the functional group. Dg of PFSAs was lower than that of PFCAs for similar number of carbons in the chain. The estimated mass flux for PFAS in an intact 1.5-mm HDPE GM varied from 38.7 to 2080.8 ng/m2/year whereas the estimated diffusive breakthrough time for PFAS in intact 1.5-mm HDPE was 1526 years or longer.