Stopping Period Research Articles

Self-avoidance dominates the selection of hippocampal replay.

Spontaneous neural activity sequences are generated by the brain in the absence of external input 1-12 , yet how they are produced remains unknown. During immobility, hippocampal replay sequences depict spatial paths related to the animal's past experience or predicted future 13 . By recording from large ensembles of hippocampal place cells 14 in combination with optogenetic manipulation of cortical input in freely behaving rats, we show here that the selection of hippocampal replay is governed by a novel self-avoidance principle. Following movement cessation, replay of the animal's past path is strongly avoided, while replay of the future path predominates. Moreover, when the past and future paths overlap, early replays avoid both and depict entirely different trajectories. Further, replays avoid self-repetition, on a shorter timescale compared to the avoidance of previous behavioral trajectories. Eventually, several seconds into the stopping period, replay of the past trajectory dominates. This temporal organization contrasts with established and recent predictions 9,10,15,16 but is well-recapitulated by a symmetry-breaking attractor model of sequence generation in which individual neurons adapt their firing rates over time 26-35 . However, while the model is sufficient to produce avoidance of recently traversed or reactivated paths, it requires an additional excitatory input into recently activated cells to produce the later window of past-dominance. We performed optogenetic perturbations to demonstrate that this input is provided by medial entorhinal cortex, revealing its role in maintaining a memory of past experience that biases hippocampal replay. Together, these data provide specific evidence for how hippocampal replays are generated.

The effect of proposed changes for the rotation and throwing phases on some kinematics and performance variables for U20 weightlifters

Weightlifters from the youth division of five clubs in the Najaf Governorate. The researcher divided the research sample into two groups (experimental and control), and the proposed changes in technical performance were applied to the members of the experimental group while traditional technical performance was applied to the members of the control group.The educational program, which consists of three educational units for each week for a period of four weeks, was put into practice after the pre-tests, which included the option of (shooting from full performance), and the results showed that there were significant differences between the two groups and in favor of the experimental group in the post-test of throwing from the full movement, which came in line with the researchers' hypothesis .In order to give the shooter the most explosive power possible and to achieve the best mechanical position by managing the pause period between the rotation and propulsion phases, he attributed the reason to the significance and impact of the proposed changes on the throwing distance for this competition.The traditional technical performance, which is in the form of bending at the start of rotation, rotation, then extension, and pushing, results in difficulty controlling the stopping period between the two phases (rotation and pushing), as well as less explosive power. This is achieved by using the instantaneous rapid bending and stretching method and without a long pause. In contrast to the suggested modification, the researcher suggested performing research on examples of discus effectiveness.

Reasonable stopping method and retracement channel support at fully mechanized top coal caving working face of 15 m extra‐thick coal seam: A case study

AbstractExtra‐thick coal seams are widely distributed in the Datong mine area in China. The rapid stopping of mining and the support withdrawal technology for extra‐thick coal seams need to be developed urgently. The reasonable stopping top coal caving distance, main roof's fracture line position, and large section roadway during the stopping period (LSRSP) support method of the header face of 15 m extra‐thick coal seam are systematically studied by using field measurement, experiment, numerical simulation, and similar material simulation methods. With the increase in stopping coal caving distance, the range of the medium and low displacement zone of the LSRSP overburden gradually expands. In contrast, the depth of the plastic zone decreases. The scope and intensity of the high‐stress area of the overlying rock in front gradually decrease and shift from deep to the outside, while the peak stress area shifts from the top coal area to the coal rib of the retracement channel. Comparing the stopping of medium‐thick and thick coal seam working face, the interaction between “main roof−unmined top coal−supports” is analyzed. The unique characteristics of the extra‐thick coal seam working face are derived: when the stopping coal caving distance is shorter than the length of the key block, the dropped coal body cannot effectively restrict the movement of key blocks. Mutual compression and subsidence occur between key blocks, making the broken coal rock block squeeze into the supports. By the simulation study of each index, the stopping coal caving distance of the extra‐thick coal seam is optimal when it is slightly larger than the length of the key block (i.e., the periodic weighting step), simultaneously, the main roof fracture line behind the supports is most favorable for stopping mining. After ensuring the stability of the LSRSP's overburden structure, the differentiated support scheme of “controlled zoning−strength grading” was proposed, and the scheme was modified and verified by simulating the support prestress field. After field practice, the roof of the retracement channel is better controlled in deformation under the joint horizontal and vertical support, the robust control effect of the combined anchor cable is noticeable, the integrity of the polyurethane network is more substantial, and the working face supports have successfully achieved a safe and rapid evacuation.

Experimental and numerical simulation on buried hot fuel oil pipelines in three modes flow regime considering temperature loss during a shutdown

Aiming to study the temperature distribution along buried pipelines containing hot fuel oil, a new large-scale laboratory is constructed from the perspective of the corresponding fluid thermophysical properties. Also, a modeling of the pipe-line, and the soil around it, was performed along the pipeline for observation of all three modes of turbulent, laminarization, and laminar flow, which is validated by experimental results. Furthermore, the appropriate data are also gathered from the actual pipeline, 107 km of the 26? pipeline between Abadan Refinery and Mahshahr Port, and the results of the experiment and modeling are reconfirmed. The experiment shows that the viscosity and fluid density of fuel oil is strongly temperature-dependent. Many experiments are performed on the parameters affected by temperature according to their importance. The method chosen to simulate three flow modes along the pipeline shows less than 2% error in turbulent and laminar zones and reveals just a 3% error to experimental data in the laminar region. The maximum safe time during the stopping period of the pipe-line and holding fuel oil in it is calculated based on the pour point of fuel oil. This time is critical for the real pipeline in sudden shutdown and is calculated 41 hours.

RESIDU ANTIBIOTIK PADA SUSU KAMBING PE YANG MENDERITA MASTITIS SUBKLINIS DI DESA AIKMUAL LOMBOK TENGAH

Subclinical mastitis is a disease that often occurs in Etawa (PE) crossbreed goat farms. Farmers in handling this disease usually use antibiotics, giving antibiotics that are not right or according to the procedure can cause residues. The presence of antibiotic residues in goat's milk can have an impact on human health such as poisoning, allergies, and microbiological disorders. This study aims to determine the incidence rate and find the presence of antibiotic residues in the milk of Etawa Peranakan goat who suffer from subclinical mastitis in Aikmual Village, Central Lombok Regency. Test results from 6 samples of etawa-crossed goat milk (PE) suffering from subclinical mastitis using the Bioassay Screening Test method showed negative results containing antibiotic residues. Negative results in the sample are marked by the absence of dead bacteria on paper discs that have been soaked with milk samples from goats that are positive for subclinical mastitis, this is evident from the absence of inhibitory zones formed. The negative effect of this milk sample is due to several possibilities, namely: The stopping period of the drug has been reached and the antibiotics used are in accordance with the dose. The duration of the presence of antibiotics in milk depends on several factors, including: dose, method of administration and type of antibiotic. In general, it is applied that the withdrawal time of narrow spectrum antibiotics is at least 5 days after treatment, for the type of antibiotics that can form a depot (broad spectrum) has a withdrawal time of 1 3 days

Non-inertial stopping characteristics of a prototype pump

The characteristics of centrifugal pump in non-inertial stopping period have not been studied better by far. In this article, the variation characteristics of transient performance of a prototype p...

Variation in Airborne Particulate Levels at a Newly Opened Underground Railway Station

The construction of a new railway tunnel for commuter trains in Stockholm was completed in 2017. It included two modern stations (Odenplan and Stockholm City) with platform screen doors (PSD) and one old station (Stockholm Södra) without PSDs. This study evaluates the concentrations of airborne particulates at the new Odenplan station, focusing on the effects of traffic operation, system age and train movement. For comparison, the other two stations in the tunnel and an above-ground railway station (Solna) were also investigated. The new platform was clean prior to opening for traffic (the average concentration of PM10 and PM2.5 was 12 and 2 µg m–3, respectively). Substantial increases in the PM10 and PM2.5 levels were observed after it came into service, with the average concentrations increasing to 120 and 30 µg m–3 after 1 week and then to 175 and 35 µg m–3 after 3 months of operation. The train movement factor (traffic frequency and train stopping period) was found to have a strong effect on the coarse-sized particle concentrations (0.3–10 µm). Comparable levels of PM10 and PM2.5 were measured at both the new Odenplan station and the old station, where the amount of traffic was similar. For the other new station, Stockholm City, where traffic was only half as frequent, the PM10 and PM2.5 levels were substantially lower.

Problems of Reconstruction of Ferrous Metallurgy Enterprises

The article gives the characteristics of the ferrous metallurgy enterprises with a very high density of placement. As part of such enterprises, there is a large number of multipurpose buildings and structures with complicated space-planning and design solutions and the same time these areas are saturated by underground and transport communications. During the reconstruction of these facilities, the large volumes of works are provided including earthworks, making massive foundations under equipment, reinforcement of reinforced concrete and metal constructions, dismantling and assembling of technological and electrical equipment, special construction works. Performing of reconstructive works requires coordination of their solutions with service departments of the enterprises. In particular, for major industries there were highlighted features that must be considered when drafting and coordinating solutions. The biggest difficulty is mounting of various technological and electrical equipment, devices and means of automation (ranged from heavy equipment to the finest contemporary domain of electronic systems of management of production processes). When this enlarger assembly of heavy equipment is carried out in extremely camped in size sights in the vicinity of the existing slag removers for casting iron, the installation and commissioning of automation tools are manufactured with running technological equipment with its short-term halt or without any. Solution of these problems requires careful shaping options for the organization of construction and installation works on the basis of focused iterating through possible reconstruction methods, priority reconstruction of technological processing shops, the sequence of execution of works, taking into account the technologically possible combination of them. The authors propose the formula for the calculation of the overall duration of the reconstruction project including the duration of the preparatory and main periods, taking into account before stopping period, stopping and after stopping periods.The article highlights the features of realization of solutions for the main period of reconstruction of the enterprises and make suggestions on implementation of works and replacement of equipment for agglomeration shops, coke oven batteries, steelmaking shops, rolling shops and blast furnaces. The article also focuses on the ways of safety production work during the reconstruction of the ferrous metallurgy enterprises.

The melting of salt hydrate phase change material in an irregular metal foam for the application of traction transient cooling

To cope with the increasing cooling loads in power electronics especially in traction, a new heat sink based on the irregular aluminium foam/salt hydrate phase change material composite was proposed for the integration into liquid cooling or heat pipe systems to provide transient cooling during the traction stationary phase. This heat sink would also be applicable to accommodate power surges or thermal buffering-related conditions. The melting point of the salt hydrate PCM was 46 °C. The coolant water was heated up to 60 °C, similar to the inlet condition in traction liquid cooling systems. The vacuum impregnation method used to create the composite resulted in a 96% impregnation ratio. The heat sink absorbed a thermal load up to 0.092 kW h with increasing charging temperature from 50 to 60 °C (from ambient: 20 °C) within an hour of heating and the PCM was fully melted. This was a combination of latent and sensible heat storage methods. The thermal capacity value matched closely with the theoretical calculation of 0.103 kW h (11% deviation). An hour of complete melting would match the stopping period of intercity trains at the terminus and the sink would be able to cool a group of 4–5 IGBTs, rated at 20 W power dissipation for each IGBT, during this stopping period. The heat balance formulated was commendable due to the small mismatch (7% deviation) between the released and absorbed heat, from the coolant to the heat sink. Therefore, it could be used to further optimise the design with alternative PCMs, foam porosities, operational conditions, thermal masses, heat exchanger configurations and so on. The effective thermal conductivity (Keff) for the composite was calculated as 10.8 W/m K and the ratio of Keff/KPCM was 24, higher than many composites previously studied in literature. In general, the heat sink would benefit in providing a transient, compact and inexpensive solution.

Neuroprotective and Therapeutic Role of Omega-3 Against Oxidative Stress and Neurotransmitter Disturbances in Rotenone-Induced Mice Model of Parkinson's Disease

The present study aimed at evaluating the protective and therapeutic efficacy of omega-3 against motor impairment and brain biochemical disturbances in rotenone-induced mice model of Parkinson's disease (PD). Sixty animals were divided into six groups (10 each): mice of the 1 st group were used as controls, they were injected subcutaneously ( s c ) with the vehicle (50 µl dimethylsulfoxide (DEMSO) + 950 µl sunflower oil /kg body weight) every other day for 30 days; the 2 nd group, mice model of Parkinson’s disease (PD), were injected (s c ) with rotenone (3 mg/kg dissolved in vehicle every other day for 30 days ). the 3 rd group, mice were given rotenone for 30 days followed by a stopping (recovery) period of other 30 days to validate the persistency of the PD model; the 4 th group (protection group), mice received orally Omega-3 oil (300 mg/kg) daily an hour before every rotenone injection for 30 days; the 5 th and 6 th groups (therapeutic groups ), mice were treated orally with Omega-3 oil daily for 7 and 15 days respectively after the induction of PD mice model. Data obtained revealed an impairment of the motor activity in mice of PD model as indicated from the decreased time of the forelimb hanging test. This was associated with a state of oxidative stress in the brain of PD model as indicated from the increase in lipid peroxidation (increased malondialdehyed, MDA, level) and nitric oxide (NO), and the decrease in reduced glutathione (GSH). A significant decrease in the levels of dopamine, norepinephrine, serotonin, AChE activity and a significant increase in TNF-α level was recorded in the PD model. The present findings show that both the protection by or oral treatment with omega-3 for 15 days could ameliorate the rotenone- induced oxidative stress and inflammation in brain of PD mice model. In addition, omega-3 either as protection or treatment daily for 15 days was effective in restoring the decrease in dopamine and norepinephrine induced in the brain of PD mice model. In conclusion, the present study demonstrates that omega-3 supplementation potentially reverses the motor, and neurochemical alternations induced by rotenone in mice model of PD.

Transient flow analysis in axial-flow pump system during stoppage

Axial-flow pumps with siphon outlet are widely used in South-to-North Water Transfer Project of China for the excellent characteristics and good performance in stopping period. The reverse rotational speed and the head of impeller are the key parameters for the system’s safety in stoppage. In this article, the computational fluid dynamics method was used for three-dimensional unsteady numerical simulations. The method based on volume of fluid model was executed on geometrical model of the whole flow system to get the variation laws of internal and external characteristic parameters. Through numerical calculation, the variation laws of the parameters were got in the pump operating condition, braking condition, and turbine condition, and the maximum reverse speed of the impeller was 203.0 r/min (−0.947 times the rated speed). Compared with the designed mode, when the air valve was opened in advance, the pump system would go through the weir flow state first, and a higher head of impeller would be got as a result. When the air valve refused to open, the pump system would get into runaway state. Comparisons of the calculated and measured results indicate the proposed computational fluid dynamics method is reliable in the simulation of the transient flow in axial-flow pump system.

The Effect of Mirror Neurons Stimulation on Syntax Development of Female Persian Autistic Children

<p>One common language disorder in autistic children is syntax disorder. The current research aims to examine the relationship between mirror neurons stimulation by intentional movements imitation and verbal imitation with syntax skill development in autistic children. This research was performed using an experimental applied design and convenience sampling method. First, the researcher designed a functional and easy model for autistic children rehabilitation based on intentional movement imitation and verbal imitation; Then, using TPR (Total Physical Response) method. A pilot study was conducted on a Persian-speaking autistic girl aged 7 in 12 sessions for four weeks in Iran University of Medical Sciences, School of Rehabilitation Sciences, and effective positive effects were observed. Then, 8 Persian-speaking autistic children were examined in terms of entrance criteria, and finally, 5 autistic girls aged 5-8 were selected and underwent training courses for 42 sessions over 14 weeks (3 20-30 minute sessions). In order to examine syntax skills of the subjects including grammatical understanding, sentence imitation and grammatical completion, before and after intervention, TOLD-P3 test was used. Each subject, as his/her Control was examined before and after intervention. Furthermore, two months after a 14-week stopping period, all the subjects were re-examined using TOLD-P3 test, and finally, results stability was examined. The research findings were analyzed using ANOVA test. The findings show that mirror neurons stimulation in autistic children through intentional movement imitation and verbal imitation has a positive effect on syntax skill improvement on these children thereby facilitating their verbal communication.</p>

Experimental Study on a Prototype Centrifugal Pump with Open Impeller During Stopping Period

Experimental Study on a Prototype Centrifugal Pump with Open Impeller During Stopping Period

Transient Characteristics of a Closed-Loop Pipe System During Pump Stopping Periods

In order to study the transient characteristics of a closed-loop pipe system with room temperature water, experiments were carried out based on different pump stopping periods from rate rotational speed to zero. Various stopping periods were realized by changing the rotational inertia of the rotors, controlling the frequency of the motor and braking the shaft. Experimental results of different operating schemes were compared, and transient flow rate of the pipe system and transient characteristics of the pump were analyzed. The influences of the kinetic energy of the loop fluid and pump rotors to the stopping periods were summarized. Results show that rapid change of the pump operating conditions occurs during the stopping period and transient flow rate of the pipe system and characteristics of the pump depend largely on the way of stopping. The kinetic energy stored in the pump can drive the impeller keeping rotating for more time after the motor is shutdown. Due to the kinetic energy stored in the loop pipe, the flow rate does not reach zero immediately after the rotational speed reaches zero. The inertia of pump rotor and fluid inertia affect the impact of fluid flow and the duration of the loop during pump stopping period.

FUEL WASTAGE & EMISSION DUE TO IDLING OF VEHICLES AT ROAD TRAFFIC SIGNALS

Among the different city of Madhya Pradesh, Indore is one of the biggest one. It has very heavy traffic during day time. Since numbers of vehicles are increasing day by day, which ultima tely increase the length of stopping period of vehi cles at most of the signals. Situation becomes worst in peak traffic hours. Resu lting excess fuel consumption and pollution load to the atmosphere. For quantifying the excess fuel consumption and polluti on load to the environment by motor vehicles studie s was carried out at different traffic signal squares of Indore. The selected traf fic signal crossings were Palasia Main, Palasia-1 st signal crossing, Gurudwara signal crossing, Bangali signal crossing, Bhowarkua signal crossing, regal signal crossing, and Mhowna ka signal crossing. Study reveals that about 5.9 x 10 5 litre per year petrol & diesel (3.6 x10 5 litre petrol and 2.3 x 10 5 litre diesels) and 1.7x10 5 kg per year of CNG are being wastage by Indore itself. This is res ulting addition of 20.2 x 10 5 kg CO 2 in the atmosphere. Extrapolating of these data at Madhya Pradesh state level conclude wastage of 5.6 x 10 6 litre per year petrol plus diesel(3.4 x 10 6 litre from petrol and 2.2 x 10 6 litre from diesel) and 1.6 x 10 6 kg/year CNG. This is resulting addition of about 1 8.7 10 6 kg CO 2/year. This excess pollution load to

PREDICTION OF "S" CHARACTERISTICS OF A PUMP-TURBINE WITH SMALL OPENING BASED ON V2F MODEL

The characteristic of a pump-turbine during the whole starting or stopping period couldn't be calculated accurately by CFD method and most of turbulence models were found inaccurate in the calculation of small opening condition, so a proper turbulence model was needed for the further study of pump-turbine. V2F model which was valid to the solid wall and SST k-ω model were used to calculate the pump-turbine with two openings that one was a small opening and the other was large opening. Results showed that V2F model can be used to simulate characteristics of pump-turbine in the whole opening range and the SST k-ω model can be used only for large openings. Results of V2F model are accuracy and it realizes the real flow in the near wall region. Results of V2F model can obtain small vortexes and some complex flow phenomenon and they are much different from results of SST k-ω model. The V2F model might be used to simulate the starting or stopping period of a pump-turbine.

Position Stability Analysis of Gripper Bars on Die-Cutting Machine

Position stability analysis of gripper bars on die-cutting machine is one of the important factor which affects machining quality and production capacity. By introducing comprehensive influence parameter period ratio such as machine speed and mechanism natural frequency,mathematical model of gripper bars in stopping period has been established. The results indicate that dynamic motion error of gripper bars in stopping period show an increasing tendency so as to affect stable position with the increasing of period ratio. To ensure a stable position state in stopping period, finally two solutions are given out to satisfy high accuracy.

Numerical Simulation of the Transient Flow in a Radial Flow Pump during Stopping Period

Three-dimensional (3-D) unsteady incompressible and non-cavitating flow in a radial flow pump during the rapid stopping period was numerically studied by CFD. The dynamic mesh (DM) method combined with non-conformal grid boundaries was applied to simulate the transient stopping process. In order to exclude the uncertainty of the unsteady inlet and outlet boundaries, a loop pumping system was established, which was composed of pipes, a reservoir with an air part on the top, and a driving pump. Simulations were performed based on the standard k-ɛ turbulence model and volume of fluid (VOF) model. Results showed that the air part in the reservoir approximated real conditions when using the VOF model. Pressure fluctuations were reduced and a sharp increase of pressure at the inlet of the pump was observed at the beginning of the stopping period. Specific transient characteristics, such as the flow-rate, head and efficiency, were analyzed during the deceleration period and compared with corresponding quasi-steady results. The deviation of the quasi-steady hypothesis in predicting the transient stopping process of radial flow pumps is thought to be caused by differences in the predicted vortex in the impeller. The transient curve showing the relationship between the instantaneous flow coefficient and total pressure rise coefficient was analyzed and compared with the quasi-steady curve. The two curves had a crossover point when the stall just occurs in the impeller during the transient process. Simulation results were also compared and validated using published data.

Ｃｒ‐Ｚｒ銅合金の摩擦圧接

An investigation has been made of friction welding of Cr-Zr copper alloy, which is very difficult to join by conventional fusion welding processes because of its high thermal conductivity and susceptibility to solidification cracking and blowhole formation. It was revealed that brake timing and stopping period had significant effect on the formation of weld interface in friction welding of Cr-Zr copper alloy. The weld wes established only in the center area of the forging sufrace during the friction stage. Severe metal flows were required to expand the weld interface to the whole forging surface to obtain the sound joint from those experiments. When the brake wes operated after applying an upset pressure, referred to as brake timing “after”, the adequate metal flow was generated in the weld. Optimized parameters were brake timing “after” and stopping period more than 0.3 s to join Cr-Zr copper alloy without defects. The joint efficitncy estimated form tensile strength wes more than 92% at the optimum bonding paremeters. All specimens failed in the soften area apart from weld interface on tensile test.

炭素鋼の位相制御摩擦圧接に関する研究

It is difficult to match joint phases at the particular position of a rotation side a fixed side using a conventional friction welding machine, because the rotating spindle does not control the exact stop position. A development of positioning controlled friction welding meets to be solved such difficulties as stop at the specified position during duration of braking. This positioning control friction welding was achieved by installing servo motor positioning system. A phenomenon of positioning control was examined by the friction welding of carbon steel. The positioning control was satisfactory performed with sufficient accuracy. The undershoot and the overshoot behaviors were observed to the specified position during operation. Heavy metal flow was observed in the vicinity of weld interface in case of positioning control. Characteristic flash was formed by the heavy metal flow during positioning control. The metal flow became heavy with the stopping period increase. The direction of metal flow was circumferential, when positioning control friction welding. The rotative direction of metal flow was changed due to the overshoot or the undershoot behavior. When stopping period was optimized, metal flow became minimized. In this examination, 0.3 s was optimum stopping period. The fracture of tensile test specimens occurred at the base metal, when the position was controlled. However, tensile strength of positioning controlled joints was equal to the strength of base metal. The positioning control did not affect on the tensile strength of welded joints.