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As the main piece of equipment used in coal mining, the scraper conveyor is always evolving to have larger capacities, longer haulage distances, and higher power. The traditional scraper conveyor drive system mostly adopts the method of “asynchronous motor + soft start device + reducer” to realize the low-speed and high torque drive. However, due to increased intelligence and extremely harsh working conditions, there is a significant risk of failure, which has a negative impact on mining efficiency. The possibility of failure increases dramatically due to the extremely hard-working environment and the rise in intelligence, which has a major impact on mining efficiency. Therefore, a new type of permanent magnet torque-limiting reduction device was designed and developed, which was highly integrated by a permanent magnet synchronous motor, a two-stage planetary reducer, and a column surface friction torque limiter. Additionally, The dynamic simulation model of the scraper conveyor and planetary reducer, the rigid-flexible coupling model of key components of the column friction torque limiter, and the control model of the permanent magnet motor were established by using ADAMS and MATLAB/Simulink software, realizing the joint simulation of the electromechanical coupling system. Dynamic response of speed, torque, and three-phase current of permanent magnet synchronous motor and speed, tension, and torque of scraper chain drive system as well as speed, torque, and meshing force of planetary drive of a scraper conveyor driven by a new type of permanent magnet torque-limiting reducer device were simulated and analyzed under impact load condition. The results show that the inrush load current with and without torque limiter protection is 2.9 and 7.7 times higher than that in stable operation, and the motor output power is reduced by about 48% under the inrush fault. The effect of shock loads on the motor at the load side is well reduced by the column friction torque limiter. When subjected to excessive shock loads, the chain drive system components are subjected to large forces between them. In this case, the torque limiter slips immediately, the system is unloaded and the drive components are protected against overload. The shock between the gears of the reducer is also increased by excessive shock loads, which are quickly and accurately protected by the torque limiter. Conventional systems are subjected to about 78% less load impact, proving that the permanent magnet limited-pitch reduction device is well suited for low-speed, high-torque engineering applications. The research findings have the potential to enhance the scraper conveyor drive system’s dependability and boost the coal machine device’s intelligence.

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Optimization of drilling processes for oil and gas and geothermal wells requires the effective use of mechanical energy for the destruction of rocks. When constructing a well, an important indicator of the drilling stage is the mechanical speed. Therefore, when performing drilling operations, operators usually use blade bits of an aggressive design and often use forced drilling modes. Drill bits under forced operation modes generate a wide range of vibrations in the drilling tools; in turn, a drill string, being a long-dimensional deformable body, causes the development, amplification, and interconnection of vibrations of different types. Vibration loads reduce the technical and economic indicators of drilling, with destructive effects on drill string elements, and cause complications and emergencies. The authors initiated the creation of an informational and analytical database on emergency situations that occurred as a result of excessive vibrations of the drill string during the construction of deep wells in the deposits of the Dnipro–Donetsk Basin. For the first time, the suitability and effectiveness of using the Smart 4 controller (“Innova Power Solutions”, Calgary, Canada) for monitoring the vibration load of the drilling tool was tested in industrial conditions, while the controller was used as a separate element in the drill string. A special module was developed for the reliable installation of the Smart 4 controller, with a power battery in the layout of the lower part of the drill string. During the testing of the proposed device for measuring vibrations in the process of drilling an inclined well, verification of the registered data was carried out with the help of a high-cost telemetry system. The implementation of the proposed innovation will allow each operator to assess the significance of the impact of vibrations and shocks on the production process and, if necessary, adjust the drilling modes or apply vibration protection devices. In addition, service departments that operate and repair drilling equipment will be able to obtain an evidence base for resolving warranty disputes or claims.

Satellites should be equipped with more and more deployable, large, flexible appendages to improve their service efficiency and reduce launch costs. The spring-driven deployment method of flexible appendages has been widely applied and generates great instantaneous shock loads on satellites, maybe affecting the safety of other flexible appendages, but the current related investigations for satellites with multiple large flexible appendages are insufficient. In this study, the deployment test of the antenna itself was conducted, and the attitude changes in a satellite during antenna deployment were telemetered. Then, a related dynamical model of the satellite was established and verified by the telemetry values of the satellite. Finally, the shock mechanism transmitted to solar arrays was analyzed, and the effect of solar array attitude was discussed. The results show that the simulated method of antenna deployment equivalent to the shock loads tested was thought to be efficient, though it could cause a small non-zero constant of the simulated angular velocities in the antenna deployment direction. The shock-induced moments, except the rotation direction of the solar array drive assembly (SADA), should be highlighted for the antenna deployment dynamic design of satellites, and the solar array attitude has few effects on the shock-induced loads at the SADA. [ABSTRACT FROM AUTHOR]

This work considers the possibility of lining the body of a dump truck with rubber. To confirm the results of experimental studies obtained during the operation of quarry dump trucks at the Omelianivsk quarry, finite-element and 3D models were created for dynamic analysis in the T-FLEX environment, simulating the loading of metal structure elements of the frame and body of quarry dump trucks. The finite element method was used to assess the stress-strain state of the elements of the load-bearing metal structures of heavy-duty quarry dump trucks. The versatility of this makes it possible to calculate different designs with different material properties in a single way. The method allows you to take into account the geometric shapes and operating conditions of the structure, the distribution in time and space (for dynamic tasks) of external loads, the properties of materials used in the structure in a fairly complete volume. To assess the accuracy of the modeling, a number of experiments were conducted to measure vibration oscillations on BelAZ 548 dump trucks. Vibration measurements were performed using a 16-channel SCADAS eSCR05 Siemens data logger using a Windows Mobile-based HP iPAQ 214 PDA with Bluetooth connectivity. Data were recorded and stored on flash cards with a capacity of 16 GB. Two different sampling rates with 24-bit resolution were used: 256 samples per second for vibration measurements. Sensors used to register the three orthogonal axes of vibration included four triaxial accelerometers on a printed circuit board.

Satellites should be equipped with more and more deployable, large, flexible appendages to improve their service efficiency and reduce launch costs. The spring-driven deployment method of flexible appendages has been widely applied and generates great instantaneous shock loads on satellites, maybe affecting the safety of other flexible appendages, but the current related investigations for satellites with multiple large flexible appendages are insufficient. In this study, the deployment test of the antenna itself was conducted, and the attitude changes in a satellite during antenna deployment were telemetered. Then, a related dynamical model of the satellite was established and verified by the telemetry values of the satellite. Finally, the shock mechanism transmitted to solar arrays was analyzed, and the effect of solar array attitude was discussed. The results show that the simulated method of antenna deployment equivalent to the shock loads tested was thought to be efficient, though it could cause a small non-zero constant of the simulated angular velocities in the antenna deployment direction. The shock-induced moments, except the rotation direction of the solar array drive assembly (SADA), should be highlighted for the antenna deployment dynamic design of satellites, and the solar array attitude has few effects on the shock-induced loads at the SADA.

On the battlefield, modern vehicles perform a variety of roles. Transportation is one of the most fundamental. Operating in different terrains, including urban areas, means exposing the crew to different hazards. To increase crew protection, passive and active protection systems are used. On the other hand, in addition to protection, support of the infantry in offensive operations is an equally important activity. The most common solution for medium wheeled vehicles is a manned turret. The weapon is a 30 mm cannon. Nowadays, there is a trend towards installing systems that allow such weapons to be operated remotely. This minimises the exposure of highly trained personnel. This paper presents the results of a numerical study of the dynamic loads on the roof-plate structure of a wheeled armoured personnel carrier resulting from the firing of the vehicle's main armament. It includes the values of the strains and stresses in the upper plate structure and the forces transmitted by the brackets connecting the roof plate to the bottom plate, and an assessment of the risk of using such a system on the safety of the vehicle structure and its crew. [ABSTRACT FROM AUTHOR]

As inferred from earthquake engineering literature, considering soil structure interaction (SSI) effects is important in evaluating the response of transmission line towers (TLT) to dynamic loads such as impulse loads. The proposed study investigates the dynamic effects of SSI on TLT behavior. Linear and non-linearmodels are studied. In the linearmodel, the soil is represented by complex impedances, dependent of dynamic frequency, determined from numerical simulations.The nonlinearmodel considers the soil non-linear behavior in its material constitutive law and foundation uplift in a non-linear time history analysis. The simplified structure behavior of a typical lattice transmission tower is assessed. The analysis of frequency and time domain are followed through varying soil stiffness and damping values. Three different shock durations are investigated. The soil-structure system with equivalent dynamic properties is determined. The behaviors achieved utilizing a rigid and a flexible base for the structures is compared to estimate the impact of taking SSI into account in the calculation. The current mainstream approach in structural engineering, emphasizing the importance of the SSI effect, is illustrated using an example where the SSI effect could be detrimental to the structure. Furthermore, the non-linear analysis results are analyzed to show the linear approach’s limitations in the event of grand deformations. [ABSTRACT FROM AUTHOR]

A vibration-based diagnostics method of large-power 1JAH5 (Siemens) DC motors over 660 kW used in paper machines is proposed in the article. When studying vibration spectrograms it was found that 8 Hz frequency shock loads considerably prevail over vibration, which corresponds to this motor rotor speed. The cause of vibration initiation generated by the motor rotor spinning was determined by theoretical methods. Vibration on the one hand appears as a result of bearings wear accompanied by bearing cage deformation and their shaft spinning axes reciprocal displacement, and on the other hand, by shaft eccentricity radii enhancement which causes dynamic loads increase affecting bearing units. The authors of the paper have come to the conclusion that in order to lower vibration of the motor it is necessary to replace the bearings with the new ones, the former due to a long-term service (over 30 years), vibration and shock load effects having exhausted their life span. [ABSTRACT FROM AUTHOR]

Anaerobic digestion for flexible biogas production can lead to digestion inhibition under high shock loads. While steel slag addition has shown promise in enhancing system buffering, its limitations necessitate innovation. This study synthesized the nitrogen-doped activated carbon composite from steel slag to mitigate intermediate product accumulation during flexible biogas production. Material characterization preceded experiments introducing the composite into anaerobic digestion systems, evaluating its impact on methane production efficiency under hydraulic and concentration sudden shocks. Mechanistic insights were derived from microbial community and metagenomic analyses, facilitating the construction of the modified Anaerobic Digestion Model No. 1 (ADM1) to quantitatively assess the material's effects. Results indicate superior resistance to concentration shocks with substantial increment of methane production rate up to 33.45% compared with control group, which is mediated by direct interspecies electron transfer, though diminishing with increasing shock intensity. This study contributes theoretical foundations for stable flexible biogas production and offers an effective predictive tool for conductor material reinforcement processes. [Display omitted] • A composite material was designed to boost flexible biogas production resilience against shock loads. • The material can be endowed with the function of dual iron-carbon electrode. • The effect of the material on resistance to concentration shock is more obvious. • The conversion of organic matter to VFA and the pathway of DIET were enhanced. [ABSTRACT FROM AUTHOR]

Rock burst represents a very dangerous phenomenon in deep underground mining, as well as for underground structures in unfavourable conditions (great depth, high horizontal stress, proximity of major tectonic structures, etc.). The rock burst problem relates to the natural and mining conditions of the rock mass. The evaluation of rock burst is becoming increasingly important as mining activities reach greater depths. In the literature, rock burst assessment challenge was tackled by many researchers using various methods. However, no study providing review and comparison of different rock burst assessment methods is available. In this paper, rock burst classification is briefly summarized. This includes a classification based on rock burst type, and another classification based on rock burst severity. As an important method for rock burst prevention, some novel energy-absorbing bolts were developed. These bolts demonstrate constant resistance under both static and shock loads and large elongation ability enabling them to withstand large deformations of rock masses under rock burst-prone conditions. Among the novel energy absorbing bolts, Modified Cone Bolt (MCB) and Constant Resistance at Large Deformation (CRLD) Bolt are selected to be presented in this paper.

The aim of this study is to find out a sustainable and cost‐effective solution to manage hazardous shock loads from metal finishing and electro‐coating industry. Results indicated that the main sources of hazardous wastewater are coming from batch chemical cleaning of degreasing basin (CCDB) (pH 13) and contains very hazardous chemicals, batch chemical cleaning of phosphating basin (CCPB) (pH 1.03) and contains high concentrations of iron (2300 mg/L) and zinc (2400 mg/L) and degreasing basin contents (DBC). Different treatment approaches were investigated. Results indicated that mixing CCDB with CCPB at their actual discharge allowed to form a self‐coagulant of metal hydroxide which was utilized to treat the (DBC) followed by sedimentation. Removal efficiency of COD (87%), TSS (94%), and oil and grease (92%) were achieved. To compare the efficiency of this treatment approach, conventional chemical coagulation of DBC was carried out using FeCl3 but the amount was very high. In conclusion, results proved the advantage of using self‐coagulation to treat DBC since it eliminates the use of external chemicals and provides an integrated solution for the three main sources of hazardous pollutants. Practitioner points: The manuscript provide an innovative and sustainable solution to the shock loads of hazardous wastewater generated from metal finishing and E‐coating industry by utilizing iron‐rich wastewater from chemical cleaning of phosphating basin and alkaline wastewater from chemical cleaning of degreasing basin to produce metal hydroxide.The metal hydroxide was cost‐effective and technically effectively than external coagulant in treating highly polluted degreasing basin content at due discharge time.Iron‐rich wastewater could be used to produce self‐coagulant of iron hydroxide.Mixing iron rich wastewater and alkaline wastewater produce iron hydroxide.Iron hydroxide is cost‐effective in treating hazardous wastewater of degreasing basin. [ABSTRACT FROM AUTHOR]

A model of dynamic deformation and fracture of composite materials is developed. This model accounts for the significant nonlinearity of shock loading diagrams with hardening, which depends on strain rate. An approach is used in which the dependence of ultimate strength on damage parameters and their variation rate is introduced in the form of constitutive relations. The proposed relations are similar to those of the Johnson—Cook model, but stresses are expressed via damage parameters and their variation rate rather than in terms of plastic deformations and the variation rate of plastic deformations. On the basis of the developed model, the impact fracture of a tubular profile made of a composite material based on carbon fiber and a polymer binder are numerically simulated. The influence of the orientation of unidirectional layers of a composite on specific absorption energy is investigated. [ABSTRACT FROM AUTHOR]

In this paper, asymmetric equations for an elliptical boundary layer in the vicinity of the conditional front of Rayleigh surface waves, which occurs in shells of revolution under shock end impacts of normal type are constructed. The technique of asymptotic derivation of these equations, based on the use of the symbolic Lurie method and the introduction of special coordinates that distinguish a small frontal zone required to reduce the original problem to an equivalent problem for an infinite shell by isolating a particular solution. The considered boundary layer complements the full description of the considered type of stress-strain state (SSS) in all sections of the phase plane. It also uses a quasi-static boundary layer of the Saint-Venant type in a small vicinity of the butt end, a parabolic boundary layer according to the two-dimensional Kirchhoff–Love theory, a quasi-plane short-wave component, and a hyperbolic boundary layer in a small neighborhood of the shear wave front. In conclusion, an example of constructing an elliptical boundary layer under shock action on the butt end of a cylindrical shell is considered. [ABSTRACT FROM AUTHOR]

This paper describes the experimental setup of combustion chamber, and the shock loads resultant of gases mixture detonation. The results of experiments performed with fully clamped circular steel plates subjected to detonation of acetylene (C2H2)–oxygen (O2) in various volume ratio and different initial pressure. The energy of deformation of plates is determined by measuring pressure of explosion chamber after detonation and the results presented in terms of central deflection of the plates. Also, in this paper, theoretical modelling is presented to predict the midpoint deflection versus impulsive loading by assuming a zero Bessel function shape of the deformed circular plate. This approach is developed based on energy method for plastic material behaviour, and since the shock wave energy is equal to the deformation energy. The strain energy of the plate can be calculated by using the initial shock load energy imparted to the circular plate. The results of this model have good agreement with the experimental values. Moreover, it has been shown that the obtained model has much less error compared with those previously proposed in the literature. [ABSTRACT FROM AUTHOR]

Since anaerobic wastewater treatment is a nonlinear and complex biochemical process, reasonable monitoring and control are needed to keep it operating stably and efficiently. In this paper, a least-square support-vector machine (LS-SVM) was employed to construct models for the prediction of effluent chemical oxygen demand (COD) in an anaerobic wastewater treatment system. The result revealed that the performance of the steady-state model based on LS-SVM for predicting effluent COD was acceptable, with the maximum relative error (RE) of 11.45%, the mean average percentage error (MAPE) of 0.79% and the root mean square error (RMSE) of 3.08 when training, and the performance fell slightly when testing. Even though, the correlation coefficient value (R) between the predicted value and the actual value of 0.9752 could be achieved, which means this model can predict the variation of effluent COD in general. The dynamic-state models under three kinds of shock loads, which were concentration, hydraulic, and bicarbonate buffer absent, showed good forecasting performance, the correlation coefficient values (R) all excelled 0.99. Among these three shocks, the dynamic LS-SVM model under bicarbonate buffer absent shock achieved the optimal performance and followed by the dynamic-state model under hydraulic shock. This paper provides a meaningful reference to improve the monitoring level of the anaerobic wastewater treatment process. [ABSTRACT FROM AUTHOR]

Ultra-deep well perforation is an important direction for the development of unconventional oil and gas resources, the security with shock loads is a difficult technical problem. Firstly, the theoretical analysis of perforated string is carried out, the dynamics models of which are established in the directions of axial, radial and circumferential. Secondly, the process of perforating with hundreds of bullets is simulated by using the software of LS-DYNA (ANSYS, Inc, Pennsylvania, USA). The propagation attenuation model of shock loads is established, and a calculation model to predict shock loads at different positions of the tubing interval has been fitted by considering multiple factors. The dynamic response of perforated string is studied, and the vulnerable parts of which are found out. Thirdly, the optimization measures are put forward for ultra-deep well perforation by the design of shock adsorption and safety distance of the packer. Finally, the field case of an ultra-deep well shows that the research method in this paper is practical, and the optimization measures are reasonable and effective. This study can provide important guidance to reduce shock damage and improve security for ultra-deep well perforation.

The performance of a thermophilic biofilter (50 °C) was evaluated to treat a mixture of gas-phase benzene, toluene, ethylbenzene, p -xylene, m -xylene, and o -xylene (BTEX), under steady- and transient-state conditions. After acclimation, steady-state total BTEX elimination capacities ranged from 6 to 360 gm −3 h −1 , depending on the total BTEX loading rate applied (8–978 gm −3 h −1 ). CO 2 production from BTEX biodegradation was found to be dependent on the total elimination capacity of the biofilter. Stratification in BTEX removal profiles along the biofilter bed height was ascertained to be a strong function of the concentrations of the individual pollutants. Under steady-state conditions, higher removal efficiencies for benzene (often 100%) was noticed in comparison to the alkylbenzene compounds at the same initial load. Furthermore, studies were carried out under shock loading and starvation conditions (transient loads) for periods of 4–6 days, showing the robustness and resilience capacity of the biofilter, as the biofilter immediately recovered its original removal efficiency when high loads were applied after the brief transient conditions. [ABSTRACT FROM AUTHOR]

Nowadays, composite materials have been increasingly used in marine structures because of their high performance properties. During their service time, they may be exposed to extreme loading conditions such as underwater explosions. Temperature changes induced by pure mechanical shock loadings cannot to be neglected especially when smart composite materials are employed for condition monitoring of critical systems in a marine structure. Considering this fact, both the thermal loading effect on deformation and the deformation effect on temperature need to be taken into consideration. Consequently, an analysis conducted in a fully coupled thermomechanical manner is necessary. Peridynamics is a newly proposed non-local theory which can predict failures without extra assumptions. Therefore, a fully coupled thermomechanical peridynamic model is developed for laminated composites materials. In this study, numerical analysis of a 13 ply laminated composite subjected to an underwater explosion is conducted by using the developed model. The pressure shocks generated by the underwater explosion are applied on the top surface of the laminate for uniform and non-uniform load distributions. The damage is predicted and compared with existing experimental results. The simulation results obtained from uncoupled case are also provided for comparison. Thus the coupling term effects on crack propagation paths are investigated. Furthermore, the corresponding temperature distributions are also investigated.

Improved ice detachment failure criteria were implemented into the finite-element dynamic analysis of iced power transmission lines subjected to cable rupture shocks, which allows the study of the ice shedding effects that have been induced by the initial shocks. The modeling method is validated first experimentally by full-scale physical tests and then numerically by comparing with previous numerical methods. The case study shows that after considering the ice detachment failure subsequent to the initial rupture shock, the dynamic response of the iced line is significantly different from that obtained with previous iced line models that ignore the induced ice shedding effects. It shows that the previous equivalent density method tends to overestimate and the previous strain method tends to underestimate the maximum values and dynamic impact factors of cable tensions and insulator forces for the iced line following conductor breakage. It also shows that the cable-ground contact effect plays quite a different role in the bare cable model and iced line models. The proposed method can help improve the structure design of transmission lines and can also be used to study the dynamic response of lines subjected to other modes of line components failure, such as clamp slippage, insulator rupture, and tower deformation. [ABSTRACT FROM PUBLISHER]

An inorganic-based bed biofilter was used to eliminate methane (CH) from an air stream under pseudo steady state, transient state (shock loads), and starvation conditions. Under pseudo steady state conditions, the effect of inlet CH concentration in the range of 1000-13,000 ppmv on the biofilter performance was studied. The air flow rate was kept constant at 3 L min, corresponding to an empty bed residence time (EBRT) of 6 min. The flexibility of the biofilter under transient conditions was evaluated by two strategies: Inlet loads (IL) varied from 13 to 65 g m h by changing inlet concentrations from 2000 to 10,000 ppmv or by changing air flow rates varied from 3 to 15 L min, separately. Finally, the effects of nutrients and CH starvations were evaluated. The biofilter performance was promising for the treatment of a wide range of concentrations of off gas emissions polluted with CH (1000-13,000 ppmv). For CH concentrations ranging from 1000 to 4000 ppmv, the removal efficiency (RE) remained higher than 75 %. The maximum elimination capacity (EC) obtained in this study was 45 g m h for an IL of 87 g m h. In case of sudden variations of ILs (13 to 65 g m h) either by changing the inlet concentration or by modifying the flow rate, the responses of the biofilter were almost instantaneous. [ABSTRACT FROM AUTHOR]

Couplings incorporating rubber-cord shells, and their viscoelastic characteristics have been studied. The effectiveness of the couplings to limit the dynamic load is shown by an example of aballmill drive. It has been found that the use of the couplings equipped withrubber-cord shells as the flexible elements allows limiting the dynamic shock loads in machinedrives. It has been shown that the elimination of resonance modes and restriction of forced torque fluctuations in the drive can be providedby selecting a limit torque for the coupling actuation, which is determined by an initial air pressure in the rubber-cord shells of the coupling. [ABSTRACT FROM AUTHOR]

Many digesters in Germany are not operated at full capacity; this offers the opportunity for codigestion. Within this research the potentials and limits of a flexible and adapted sludge treatment are examined with a focus on the digestion process with added food waste as co-substrate. In parallel, energy data from a municipal wastewater treatment plant (WWTP) are analysed and labscale semi-continuous and batch digestion tests are conducted. Within the digestion tests, the ratio of sewage sludge to co-substrate was varied. The final methane yields show the high potential of food waste: the higher the amount of food waste the higher the final yield. However, the conversion rates directly after charging demonstrate better results by charging 10% food waste instead of 20%. Finally, these results are merged with the energy data from the WWTP. As an illustration, the load required to cover base loads as well as peak loads for typical daily variations of the plant's energy demand are calculated. It was found that 735 m³ raw sludge and 73 m³ of a mixture of raw sludge and food waste is required to cover 100% of the base load and 95% of the peak load. [ABSTRACT FROM AUTHOR]

A pilot-scale biotrickling filter (BTF) was established in treating the waste gases that are intermittently produced from an automobile paint-manufacturing workshop. Results showed that the BTF required longer time to adapt to the aromatic compounds. The removal efficiencies (REs) for all aliphatic compounds reached more than 95% on day 80. Aromatic compounds were not easily removed by the BTF. The REs obtained by the BTF for toluene, ethylbenzene,m-xylene,o-xylene andp-xylene on day 80 were 72.7%, 77.2%, 71.9%, 74.8% and 60.0%, respectively. A maximum elimination capacity (EC) of 13.8 g-C m−3 h−1of the BTF was achieved at an inlet loading rate of 19.4 g-C m−3 h−1with an RE of 72%. Glucose addition promoted the biomass accumulation despite the fact that temporal decrease of REs for aromatic compounds occurred. When the inlet loading rates exceed 11.1 g-C m−3 h−1, the REs of the aromatic compounds decreased by 10% to 15%. This negative effect of shock loads on the performance of the BTF can be attenuated by the pre-treatment of the photocatalytic reactor. Nearly all components were removed by the combined system with REs of 99%. [ABSTRACT FROM PUBLISHER]

In this series of articles, the potential impacts of a number of operational ‘hazardous events’ on membrane bioreactors (MBRs) removal performance were investigated. The hazardous events assessed included salinity shock, 2,4-dinitrophenol (DNP) shock, ammonia shock, organic carbon shock, feed starvation, loss of power supply, loss of aeration, complete wash out of biomass, defective fibres, and physical membrane damage. This initial study focuses on the removal of key bulk water quality and operational parameters, i.e. changes in pH, turbidity, chemical oxygen demand (COD), dissolved organic carbon (DOC), biomass concentrations, capillary suction time (CST) and membrane fouling rate. DNP, salinity and organic carbon shock conditions were shown to significantly impact removal of organic matter (in terms of COD and DOC). These findings suggest that changes in COD and DOC concentrations were determined to be effective parameters for monitoring the impacts of these shock load events. Feed starvation significantly impacted biomass concentrations but the overall system performance remained relatively resilient, as it continued to achieve effective COD and DOC removals. The results from physical membrane damage experiment confirm that turbidity is an effective indicator for online monitoring of physical membrane damage. The results of this study can assist with validation of MBR processes. [ABSTRACT FROM AUTHOR]

In complement to the initial study assessing the impact of hazardous events on membrane bioreactor (MBR) bulk performances, detailed assessment of the consequences of similar events has now been conducted on the removal of a wide range of trace organic chemical contaminants. The investigated chemicals include 12 steroidal hormones, 4 xenoestrogens, 2 pesticides, 23 pharmaceuticals and personal care products. Under salinity, DNP, ammonia and organic carbon shock conditions, overall removal of hydrophobic chemicals (log D pH7 ≥2.5) was not or only slightly affected. Since these chemicals are largely adsorbed to biomass, these results imply that biotransformation within the biomass structure itself was maintained. However, removal of hydrophilic chemicals (log D pH7 <2.5) was commonly observed to be impeded under shock load conditions, indicating loss of bioactivity. This was observed primarily for chemicals which have low or moderate biotransformability. In comparison, easily biotransformable chemicals were largely removed. The susceptibility of less readily biotransformable hydrophilic chemicals to shock loads was due to their reliance upon specific organisms or metabolic pathways for their biotransformation. The results of these experiments show that hydrophilic chemicals with low biotransformability (e.g., sulfamethoxazole, ketoprofen, gemfibrozil and naproxen) could be sensitive indicators for monitoring impacts of hazardous events on removal of trace organic chemicals by MBRs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Engineering the National Technical University of Ukraine 'Kyiv Polytechnic Institute' is the property of National Technical University of Ukraine KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Autotrophic nitrogen removal from ammonium-rich wastewaters by partial nitrification–anaerobic ammonia oxidation (PN–ANAMMOX) offers advantages such as energy and resources saving compared with conventional treatment. In view of substrate fluctuations in real applications, performance stability of PN–ANAMMOX was investigated in a new lab-scale internal-loop airlift bio-particle (ILAB) reactor. The response of steady-state reactor to substrate concentration shocks was evaluated at 439.49 mg N/L (shock A) and 489.49 mg N/L (shock B) for 0.5 hydraulic retention time (HRT) and 1.0 HRT respectively. Higher substrate concentrations such as 613.09 mg N/L (shock C) and 629.00 mg N/L (shock D) were also tested for 0.5 HRT and 1.0 HRT respectively. The intensity and duration of shocks (A–D) proportionately affected the disturbance, inertial and recovery phase of the reactor. However, the reactor showed resilience to substrate concentration shocks by tolerating higher pH and maintaining its primary functions in shocks. The inhibition of bio-reaction triggered by substrate concentration shocks was totally reversible and performance indicators returned to steady-state level soon after the end of shocks. The reactor demonstrated full recovery from all shocks with respective recovery time of 13 h, 18 h, 19 h and 23 h and it was capable of recovering 100% even from most disturbing shock D (629.00 mg N/L; 1.0 HRT). The effluent ammonium was sensitive parameter which shot up to 20.5 times the steady-state value and it could be used to monitor the reactor performance. The study results revealed that PN–ANAMMOX was robust and it was not prone to temporary adverse effects of substrate concentration shocks. [ABSTRACT FROM AUTHOR]

Precision-guided projectiles (PGPs) typically deployed in smart munitions are operated and guided by highly sophisticated embedded electronic systems (EES). These PGPs are subjected to severe shock loads resulting from the ignition of the propellant during their launch. These shock loads, which are typically characterised by high intensity, short duration and wave reflections at varied frequencies, often lead to the failure of the EES. It is the objective of this work to conduct a comprehensive multiphysics analysis of the launch process of PGPs accounting for coupling and interaction effects between the different media (propellant, PGP, confined volume and free space). Specifically, we investigated the entire launch process that include the ignition of the propellant to observe local and global features of the setback, set forward pressure and acceleration histories using explicit axisymmetric Lagrangian-Eulerian finite element simulations. In this work, we also examine the severity and frequency of the reflected waves as well as the springback of the PGPs resulting from these local oscillations as they exit the muzzle. In addition, the flight state transition due to muzzle exit in terms of pressure and flow velocity is also discussed. Our results reveal the complex phenomena associated with the dynamic response of the PGPs and pressurization process resulting from the ignition of propellant during launch that are characterized by high oscillatory pressure profiles and projectile springback. [ABSTRACT FROM AUTHOR]

Equations are provided for calculating and establishing a relationship in the form of an integral curve between emissions the probability of their occurrence. Regularities are revealed for the effect on emissions: number of fields and the number inter-electrode gaps (IEG) in a field, number of faulty gaps between electrodes, field electrode shaking regimes, and inter-electrode distance. Recommendations are formulated for electrostatic precipitator construction for effective cleaning conditions with prolonged operation. [ABSTRACT FROM AUTHOR]

The objective was to investigate the feasibility of anaerobic baffled reactor (ABR) treating real purified terephthalic acid (PTA) wastewater. The anaerobic biological treatment of real PTA wastewater was conducted in a pilot-scale ABR of five compartments, and the performance of ABR was tested when the hydraulic retention time (HRT) decreased from 40.0 to 25.0 h. After approximately four months of operation, the chemical oxygen demand (COD) removal efficiencies ranged from 67 to 81% at 3.60-5.76 kgCOD/m3/d feeding. Further, the TA and COD removal efficiency markedly decreased in the 1st compartment when the HRT decreased, but both of them kept increasing in the following compartments, indicating that the ABR showed high removal efficiency of PTA wastewater and exhibited excellent stability to shock loads. Additionally, the production of volatile fatty acid (VFA) reduced, the pH value increased, and the oxidation-reduction potential (ORP) decreased in the latter compartments, demonstrating that the compartmentalization offered well staged multi-phase anaerobic environment to treat PTA wastewater. Therefore, it could be concluded that the compartmentalization characteristic could effectively protect from shock loads and keep the stability of the whole ABR system for treating real PTA wastewater. [ABSTRACT FROM AUTHOR]

Changes in the dielectric constant and dielectric loss tangent of water that was first subjected to impact loads under the action of an alternating magnetic field were determined quantitatively using a micro-wave system, which allows solution of the inverse problem. The results of measurements of the optical spectrum of water in the 'transmission' mode, which was subjected to a shock load, in comparison with the optical spectrum of distilled water, are described. [ABSTRACT FROM AUTHOR]

Abstract: Membrane bioreactor (MBR) is a promising technological option to meet water reuse demands. Though MBR provides effluent quality of reusable standard, its versatility to shock loads remains unexplored. The present study investigates the robustness of MBR under sodium chloride shock load (5–60g/L) conditions. A bench scale aerobic submerged MBR (6L working volume) with polyethylene hollow fiber membrane module (pore size 0.4μm) was operated with synthetic wastewater at steady state OLR of 3.6gCOD/L/d and HRT of 8h. This resulted in 99% TSS removal and 95% COD and TKN removal. The COD removal during the salt shock load was in the range of 84–64%. The TSS removal showed maximum disturbance (88%) with a corresponding decrease in biomass MLVSS by 8% at 60g/L shock. TKN removal was reduced due to inhibition of nitrification with increasing shock loads. It took about 4–9days for the MBR to regain its steady state performance. [Copyright &y& Elsevier]

A procedure and results of experimental determination of the vibroaccelerations of a cylindrical shell filled with a continuum (water, clay, or sand) are presented. The dependence of the vibroaccelerations and natural frequencies of the shell on the density of the continuum is studied. It is established that the vibroaccelerations are maximum at resonance. [ABSTRACT FROM AUTHOR]

In the industrial operation of biotrickling filters for hydrogen sulfide (H2S) removal, shock loads or starvation was common due to process variations or equipment malfunctions. In this study, effects of starvation and shock loads on the performance of biotrickling filters for H2S removal were investigated. Four experiments were conducted to evaluate the changes of biomass and viable bacteria numbers in the biotrickling filters during a 24-d starvation. Compared to biomass, viable bacteria numbers decreased significantly during the starvation, especially when airflow was maintained in the absence of spray liquid. During the subsequent re-acclimation, all the bioreactors could resume high removal efficiencies within 4 d regardless of the previous starvation conditions. The results show that the re-acclimation time, in the case of biotrickling filters for H2S removal, is mainly controlled by viable H2S oxidizing bacteria numbers. On the other hand, the biotrickling filters can protect against shock loads in inlet fluctuating H2S concentration after resuming normal operation. When the biotrickling filters were supplied with H2S at an input of lower than 1700 mg/m3, their removal efficiencies were nearly 98% regardless of previous H2S input. [ABSTRACT FROM AUTHOR]

The paper outlines a method and results of experimental determination of vibratory stresses in a shell structure contacting with a medium. The stresses peak at the junction between the shell and the branch pipe. It is established that when the shell is in contact with the medium, the vibratory stresses are much higher, while the vibratory accelerations are much lower [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to investigate the resistance to hydraulic shock loads of flocculent versus granular sludge used in UASB reactors treating sewage with high solids content. Step-wise shock loads were conducted through decreasing HRT to examine the extent of reducing this parameter without significantly changing COD removal efficiency of the reactor. The lowest HRT of 4h resulted in only 3–4% reduction in the COD removal efficiency and the effluent contained low VFAs. Both sludge types have been also tested under transient hydraulic shock loads, which represent the wide variations between peak and average sewage flows occurring in small communities (rural areas). Up to 6 times the average flow no significant impact was observed on reactor performance except during and few hours after applying the shock loads. [Copyright &y& Elsevier]

Abstract: A model to predict the accumulation of soluble microbial products (SMP) in anaerobic chemostats during steady-state and transient conditions is presented in this paper. The model incorporates the concept of production and degradation of extracellular polymeric substances (EPS or ECP) as part of SMP, and was used to predict SMP production during hydraulic and organic shock load experiments in anaerobic continuously stirred tank reactors (CSTRs). For most variables the model predicted reasonably well the shock loads, and the best-fit values of the main parameters provided valuable information on the types of SMP that predominate under particular culture conditions. According to the model, during steady-state conditions ∼58% of the SMP are utilization-associated products (UAP) whilst ∼42% are biomass-associated products (BAP) of which ∼7% are soluble EPS (sEPS). During the hydraulic and organic shock loads the importance of BAP and sEPS decreases and the UAP accounts for up to 95% of the SMP. [Copyright &y& Elsevier]

Abstract: This paper describes the application of the inverse fluidization technology to the anaerobic digestion of wine distillery wastewater. In this reactor, a granular floating solid is expanded by a current of gas. The carrier particles (Extendospheres™) were chosen for their large specific surface area and their low energy requirements for fluidization. The experimental procedure was defined to examine the effect of transient changes in organic load on the performance of an anaerobic inverse turbulent bed (ITB) reactor. Moreover, in order to evaluate treatment efficiency, the active biomass concentration was estimated using the phospholipids analysis. The ITB bed reactor appeared to be a good option for anaerobic treatment of high strength wastewater, particularly for the treatment of wine distillery wastewater. The system attained high organic loading rate (OLR) with good chemical oxygen demand (COD) removal rates and it exhibited a good stability to the variations in OLR and HRT. It was found that the main advantages of this system are: low energy requirement because of the low fluidization velocities required; there is no need of a settling device, because solids accumulate at the bottom of the reactor, so they can be easily drawn out and particles with high-biomass content can be easily recovered. Lipid-phosphate concentration has been revealed as a good method for biomass estimation in biofilms since it only includes living biomass. The comparison of the measured concentration of volatile attached solids with the estimated active biomass concentration by means of phospholipids analysis indicated that extremely high active biomass concentrations can be maintained in the system. [Copyright &y& Elsevier]

Abstract: Fuel cell power for locomotives combines the environmental benefits of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. A North American consortium, a public–private partnership, is developing a prototype hydrogen-fueled fuel cell-battery hybrid switcher locomotive for urban and military-base rail applications. Switcher locomotives are used in rail yards for assembling and disassembling trains and moving trains from one point to another. At 127tonnes (280,000lb), continuous power of 250kW from its (proton exchange membrane) PEM fuel cell prime mover, and transient power well in excess of 1MW, the hybrid locomotive will be the heaviest and most powerful fuel cell land vehicle yet. This fast-paced project calls for completion of the vehicle itself near the end of 2007. Several technical challenges not found in the development of smaller vehicles arise when designing and developing such a large fuel cell vehicle. Weight, center of gravity, packaging, and safety were design factors leading to, among other features, the roof location of the lightweight 350bar compressed hydrogen storage system. Harsh operating conditions, especially shock loads during coupling to railcars, require component mounting systems capable of absorbing high energy. Vehicle scale-up by increasing mass, density, or power presents new challenges primarily related to issues of system layout, hydrogen storage, heat transfer, and shock loads. [Copyright &y& Elsevier]

Abstract: With the aim of improving knowledge about the stability and reliability of anaerobic wastewater treatment systems, several researchers have studied the effects of operational or environmental variations on the performance of such reactors. In general, anaerobic reactors are affected by changes in external factors, but the severity of the effect is dependent upon the type, magnitude, duration and frequency of the imposed changes. The typical responses include a decrease in performance, accumulation of volatile fatty acids, drop in pH and alkalinity, change in biogas production and composition, and sludge washout. This review summarises the causes, types and effects of operational and environmental variation on anaerobic wastewater treatment systems. However, there still remain some unclear technical and scientific aspects that are necessary for the improvement of the stability and reliability of anaerobic processes. [Copyright &y& Elsevier]