Shock Phenomenon Research Articles

Culture Shock Phenomenon in New Students at the North Sumatra State Campus

Penelitian ini bertujuan untuk melihat fenomena yang terjadi yakni culture shock pada mahasiswa tingkat awal atau lebih akrab dikenal pada mahasiswa baru. Penelitian ini menggunakan pendekatan kualitatif dengan menggunakan jenis instrumentasi berupa wawancara. Adapun subjek dalam penelitian ini ialah mahasiswa baru yang berada di 3 kampus negeri di wilayah Sumatera Utara yakni 2 mahasiswa berasal dari UIN Sumatera Utara, 1 mahasiswa berasal dari UIN Syuhada Padang Sidimpuan dan 1 mahasiswa berasal dari Universitas Sumatera Utara. Dari hasil wawancara yang telah dilakukan oleh peneliti didapatkan bahwa mahasiswa baru mengalami culture shock di dunia perkuliahan karena 3 hal yakni kurangnya pemahaman budaya baru terkait budaya akademik, penyesuaian akan suasana kampus (penyesuaian lingkungan baru, bahasa dan juga budaya), adanya perbedaan sistem pembelajaran di perguruan tinggi dengan tingkat SMA.

Adaptasi Mahasiswa Dalam Mengatasi Culture Shock Dalam Perkuliahan

The shift from a high school environment to a college environment brings greater demands. This condition can cause the emergence of the culture shock phenomenon. This phenomenon underscores the importance of students having the ability to adapt to all demands that arise during lectures. Lecture adaptation refers to student interaction with the lecture environment. Considering the fact that lecture adaptation is complex, the forms of lecture adaptation are divided into 4 including academic adaptation, social adaptation, emotional adaptation, and adaptation to the institution. The purpose of this study is to find out more deeply about the adaptation carried out by students who experience culture shock in lectures. This research uses a qualitative method, to find out more about the adaptation carried out by students. The results of the study found that 1 in 4 students had not reached the adjusment stage, due to the complexity of adaptation to lectures. The three students who succeeded in adapting were none other than their efforts by being open to change, learning to develop themselves, and social support from dominant friends to help students adapt.

Study of IL-4 and IL-6 Levels and Complement Activity Comparatively in Blood and Lymph in Experimental Anaphylactic Shock and Arthus Phenomenon

The levels of interleukins IL-4 and IL-6 and the activity of complement in blood and lymph were studied in experimental anaphylactic shock and the Arthus phenomenon. The experiments were carried out on 27 Winstar rats in two series. The studied parameters of interleukins IL-4 and IL-6 and complement activity in the blood and lymph of intact animals served as control. The results of the study showed that the level of IL-4 in anaphylactic shock increases and IL-6 decreases. On the other hand, with the Arthus phenomenon, the level of IL-6 increases, IL-4 decreases. The titer of complement in atopic reactions sharply decreases, and it indicates the participation of complement together with IgG in the elimination of the allergen. In immunocomplex reactions, the complement titer also decreases.

Effect of valve opening on starting performance of pump as turbine.

The study on transient characteristics of pump as turbines during atypical startup has not been deeply explored yet. In order to reveal the transient characteristics of a small centrifugal pump reversing as turbine during startup process in this paper, the transient hydraulic performance experiments are conducted for three steady rotational speed cases. Under the condition of each case, three, five and, three valve opening scenarios are completed to measure the performance. The dimensionless analysis are also employed so as to better reveal transient behavior of the pump as turbine during atypical startup. The results show that the rise rate of each performance parameter is different, wherein the shaft power and rotational speed have the fastest rising rate, followed by the flow rate, and the head rise is the slowest. It is clearly seen that the shock phenomenon in static pressure easily occurs at the outlet of pump as turbine. With the increase of valve opening, the dimensionless flow rate, head and, power coefficient all show the evolution trend of gradually increasing.

Effect of Gas Type on Flow Characteristics in a Circuit Breaker under Cold Flow Scenario

This paper presents first stage of supersonic flow modelling in gas circuit breakers without an arc. Flow characterisation focused on shock and flow separation phenomenon. Velocity deceleration caused by shock will play a significant role in determining arc cooling performance and will impact thermal interruption capability. Gas properties such as specific heat ratio, density, and viscosity influenced the flow characteristics including shock location, strength and the flow separation process.

An Analysis of Factors of Culture Shock and Culture Shock Stages Occurred in the Main Character of She Smells of Turmeric Novel

Culture shock occurs because of the culture gap and differences, such as habit, behaviour, values, religion, tradition, and other cultural aspects. The symptoms of a sojourner who fights the shock are explained by the factors of culture shock and how they combat the cultural changes that are causing the shock which described in four stages. This study aims to elucidate the existence factor of culture shock and the stage of culture shock that corresponds to the protagonist of the novel "She Who Smells Turmeric". This study is an application of the culture shock stage theory carried out by Karvelo Oberg in 1960. Researcher used romances as data sources and scenes from novels as the data. The research method is a descriptive qualitative method. Researchers collected data by repeatedly reading the novel and highlighting scenes that could be considered as data. The researcher applied interactive analysis, which he performed three steps such as data reduction, data display, and data inference. As a result of collecting and analysing the data, the researchers found 26 data found as features of the culture shock phenomenon and 84 data found as four features to explain the factors that referred to CeCe as a guest who fought culture shock in Jakarta. We found 110 data consisting of data. Culture shocks CeCe after graduating from Los Angeles.

Researching hydraulic shock phenomenon in complex hydraulic manifolds

The proposed method describes parameters change of the working environment in any section of a complex hydraulic manifold over time at a non-stationary, arbitrarily specified flow, the manifold is bounded by elements of arbitrary stiffness. The methodology uses the theory of a real compressible fluid.

Investigation on double shock in vibration response of the gear pair with spalling defects

As an important component, the gear pair is frequently used in the mechanical transmission. If there is a localized spalling defect on the gear pair, the double shock phenomenon in the vibration response can be observed. In order to reveal the mechanism, an 8DOFs dynamic model for the gear pair is established, the symmetric and asymmetric rectangular spalling defects are considered, the torsional deformation is introduced. Meanwhile, the change law of the double shock during the defect expansion is explored. From the results, the double shock is caused by multiple changes in meshing stiffness, the amplitude and distribution range are closely related to the defect sizes. When the localized defect is extended along the length and depth directions, the amplitude of the double shock is significantly increased. If the defect area is asymmetric along the center plane, the torsional deformation of the gear pair will be generated. Then, the meshing stiffness is reduced, and the double shock becomes more obvious. Finally, through the finite element method and the experiment, the established model is confirmed.

Investigation of the Stress-Strain State of a Rectangular Plate after a Temperature Shock

In this paper, the temperature shock phenomenon is considered. This phenomenon occurs during the operation of engineering structures on Earth and in outer space. A rectangular plate has been selected as a structural element exposed to temperature shock. It has a rigidly sealed edge and three free edges. A one-dimensional third initial boundary value problem of thermal conductivity was posed and solved to study the stress–strain state of the plate. Fourier’s law was used to solve this problem, taking into account the inertial term, since the temperature shock is a fairly fast-dynamic phenomenon. It was believed that all the thermophysical properties of the plate are constant and do not depend on its temperature. As a result, the temperature field of the plate was obtained after the temperature shock. This temperature field generates temperature stresses inside the plate, which lead to temperature deformations. To determine these deformations, the initial boundary value problem of thermoelasticity was posed and solved in this work. The Sophie Germain equation was used while solving this problem. To describe the plate, the theory of flexible plates was used, taking into account the stresses in the middle surface of the plate. Next, the accuracy of analytical solutions for the points displacement of a homogeneous plate subjected to a temperature shock was investigated. The temperature field was constructed using a numerical simulation. Functions of the displacement vector components were obtained using approximate analytical solutions. The accuracy of approximate analytical solutions for the components of the plate points deformation vector was estimated. The obtained results allow us to describe the stress–strain state of the plate after the temperature shock. The results of this work can be used in the design of engineering structures for both terrestrial and space purposes in terms of stability calculations and the implementation of deformation constraints.

Impact of COVID-19’s supply and demand shocks on the household economy of tilapia smallholder farmer

PurposeThis study aims to verify the impact of the supply shock (fall in harvested output) and demand shock (fall in household income) due to the pandemic on the consumption of necessities and household savings of tilapia's smallholder farmer.Design/methodology/approachThe researchers randomly chose 144 households as research samples using the proportional random sampling technique in Padang Jaya District, North Bengkulu Regency. Researchers collected data on household income, farm losses, household consumption for basic needs, labor demand, use of production inputs, the amount of output sold and saving both during and before the pandemic. The data were collected from the sample using a questionnaire prepared by the researchers. This study used a simultaneous equations system for arranging tilapia's smallholder farmer household economic model.FindingsThis study verified that the demand shock phenomenon makes households more severe than the supply shock phenomenon. The demand shock phenomenon made worse-off tilapia smallholder farmers because it caused their household savings to drop during the pandemic. The fall in savings will disrupt the stability of consumption of household necessities (health, food, education and clothing) in the future.Originality/valueThe main contribution of this study was providing empirical evidence about the impact of the demand and supply shock of COVID-19 on the most vulnerable entities in the Indonesian freshwater aquaculture industry, namely, smallholder farmer households of freshwater aquaculture fish.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-08-2022-0554.

Dynamics Analysis and Chaos Identification of Compound Pendulum Jaw Crusher with Joint Clearance

A dynamic model of the working mechanism of a compound pendulum jaw crusher with clearance is established by the Lagrange multiplier method (LMD) based on the L-N contact force model and modified Coulomb friction force model. The correctness of the dynamic model is verified by MATLAB and Adams comparison simulation, and the best selection range of driving speed and clearance size is determined according to the laminating crushing theory (LCT). The effects of driving speed and clearance size on the shock and chaos phenomenon in the clearance mechanism are analyzed, as well as the vibration force applied to the foundation. The results show that, under the premise of meeting the requirements of crusher production capacity, increasing the driving speed and reducing the clearance size can weaken the shock and chaos phenomenon during the operation of the mechanism, improve the dynamic performance and enhance the operation stability, and the service life of foundation is prolonged with the stability of vibration force. Furthermore, the optimal combination of driving speed and clearance size is determined, which provides a theoretical basis for the optimization of the vibration force of the jaw crusher.

전기자동차 스플라인 품질과 축 불균형에 의한 충격성 소음 개선에 대한 연구

Impact noise generated in electric vehicles in the 200 Hz ~ 500 Hz is perceived as rumble noise of an internal combustion engine. It is one of the biggest noise problems during electric vehicle development. This noise is caused by a shock phenomenon generated in each revolution due to interference between the minor diameter of the motor shaft spline and the reducer input shaft spline due to misalignment. Through spline measurement comparisons and spline LDP analysis results, the minor diameter of the motor shaft and its misalignment have proved to be important factors. To eliminate spline impact noise and maintain the spline

Numerical Simulation of Internal Flow Characteristics and Pressure Fluctuation in Deceleration Process of Bulb Tubular Pump

In order to explore the change in internal and external characteristics and the pressure fluctuation of the large bulb tubular pump unit during deceleration, a transient and steady three-dimensional (3D) numerical simulation is executed, based on the standard k-ε turbulence model and the change in boundary conditions such as flow rate. Finally, the pressure fluctuation data are analyzed by the wavelet method. There is a good agreement between the experimental data and numerical simulation results. During the deceleration process of the unit, the head decreases linearly while the efficiency remains stable. Meanwhile, the shock phenomenon and hysteresis effect appear before and after the unit head deceleration. Although there are vortex and backflow in the outlet conduit during deceleration, the pressure distribution on the suction surface of the impeller blades changes uniformly and significantly. The pressure fluctuation changes on the inlet surface of the impeller are more obvious during the deceleration: the closer to the hub, the greater the pressure, and this change decreases with decreasing radius. The fluctuation energy is mainly concentrated in the high-frequency region of 100–120 Hz and decreases uniformly with the deceleration of the rotational speed. This paper provides a reference for the energy utilization and safe operation of the water pump unit in adjusting speeds with variable frequency.

Analysis of hydraulic loss of the centrifugal pump as turbine based on internal flow feature and entropy generation theory

The role of clean and renewable energy such as hydropower in energy saving and emission reduction has become more and more prominent as the breakthrough of related technologies. As a kind of hydraulic machinery, energy losses in pump as turbine (PAT) always exist. In this study, entropy generation theory is introduced to analyze the distribution of hydraulic losses of PAT owing to limitations of the traditional approach based on the pressure drop method. The results of numerical simulation are in good agreement with the results of experiment on hydraulic performances. The energy losses mainly focus on guide vane, volute and runner under different flow rates, accounting for 49.73%–58.07%, 20.13%–22.45% and 16.81%–23.23% respectively. And the wall effect and velocity fluctuation are primary factors of entropy production, together accounting for more than 98%. Results of comparison between wall entropy generation rate and wall shear indicate that wall shear stress has a great contribution to the losses on the blade of guide vane and runner. Shock phenomenon, backflow and vortices are considered to be primary hydraulic factors to irreversible energy losses in PAT. This research also reveals that the asymmetric vortex rope in volute is the dominant source of entropy generation. The results of distribution of entropy generation in different components of PAT can provide certain help for optimizing corresponding structures.

Energy loss of radial inflow turbine for organic Rankine cycle using mixture based on entropy production method

The radial inflow turbine is the core component of the organic Rankine cycle(ORC) system. Based on the internal flow field of the turbine analyzed by computational fluid dynamics (CFD), the energy dissipation of a radial inflow turbine with variable guide vane is determined by the entropy production analysis method. In the presented work, the mixture of R245fa/R134a is selected as the working fluid, and the effects of tip clearance and mixing ratio on the flow loss characteristics are investigated. The results show that the high entropy production region in the stator is caused by leakage vortex and shock phenomenon, while the passage vortex and leakage vortex are the reasons for the high loss area in the rotor. The total volume entropy production of rotor is mainly composed of the passage zone, which is significantly higher than that of the stator. As the tip clearance increases from 3% to 10%, the total entropy production of stator and rotor increases by 54.5 and 161.7% respectively, and the output power and isentropic efficiency of the turbine decrease by 14.7% and 14.6% respectively. With the increase of R245fa mass fraction, the total volume entropy production of the stator and rotor decreases linearly. Compared with R134a, the turbine isentropic efficiency of R245fa increases by 3.1%.

INVESTIGATION OF PULSE VIBRATION OF THE PERIODICALLY WORKING INJECTOR OF THE MILKING WASHING SYSTEM

As a result of the analysis of technical and technological support of washing of milking installations it is established that the most effective are circulating systems of washing with regulated formation of a stopper mode with use of air injectors on the basis of automatic control. The consequences of periodic operation of the injector is the phenomenon of hydraulic shock, which is caused by a sudden change in the phase distribution of the flow of two-phase washing solution. This leads to a sudden change in the momentum of the two-phase washing solution, causing a pressure wave moving through the system. This pressure wave can lead to the destruction of milk deposits on the walls of the milk line, as well as to possible damage to the equipment of the milk system. The aim of the study is to increase the efficiency of the milking system flushing system by using pulsed vibration of a periodically operating injector. As a result of numerical simulation of the process of washing the milk line of the milking parlor using an injector in the software package STAR-CCM + was determined by the dynamics of changes in vacuum pressure at a distance from the injector (p (0 m), p (1 m), p (2 m), p ( 3 m), p (4 m), p (5 m)) and the dynamics of changes in the content of components of the multiphase medium (washing solution αf, air αg, milk αm) for four options: the injector is constantly closed, the injector is constantly open and the injector is periodically opened (1 s and 9 s) and closes (1 s and 9 s). It is established that the use of a periodic injector allows to reduce the milk content in the milk line faster and by a larger value, which indicates a better washing process. The addition of the physical-mathematical apparatus of the hydraulic shock phenomenon for a periodically operating air injector of the flushing system allowed to establish that the rate of pressure change depends on the velocities and concentrations of phases of two-phase washing solution, ie its flow regime and shock wave propagation velocity. Therefore, the rate of pressure change Δp / Δt is chosen as a criterion for the action of hydraulic shock.

Transient response analysis of FG-CNTRC curved composite panel under multi-directional initially stresses resting on nonpolonomial elastic foundation

Due to importance of exploring novel ways to protect systems from detrimental influences of thermal shock phenomenon, this study aims at analyzing the transient coupled poro/thermoelasticity response of functionally graded CNT reinforced (FG-CNTR) nanocomposite panels surrounded by non-polynomial kind of elastic foundation. In addition to thermal shock, the mentioned nanocomposite structure is subjected to initial mechanical loads in different orientations. As the accuracy of the results is of high prominence to guarantee reliability of the practical designs, the governing equations are developed on the basis of the exact type of elasticity theory known as three-dimensional form. Also, analytical solution is determined by applying Navier approach to solve the governing differential equations for simply-supported boundaries. Energy balance equation is utilized to determine the temperature gradient of the cylindrical panel considering the assumptions that the internal surface is fully isolated and the external one is subjected to thermal shock loading. Modified type of Dunber and Abate’s approach is implemented to inverse the Laplace transform in order to map the response of the system from Laplace into time domain. Convergence of the determined deflection, shear stresses, and temperature versus passing time is analyzed and confirmed. The acquired numerical results elucidate the role of different factors such as mid-radius to thickness ratio, volume-fraction, and scattering pattern of CNT in the transient coupled poro/thermoelasticity response of the FG-CNTR nanocomposite cylindrical panel. As a valuable result, it is found that increasing the volume-fraction of CNT applies negative impacts on the variation of the transverse shear stress.

Heat shock proteins with an emphasis on HSP 60.

Heat shock phenomenon is a process by which cells express a set of proteins called heat shock proteins (HSPs) against heat stress. HSPs include several families depending upon the molecular weight of the respective protein. Among the different HSPs, The HSP60 is one of the main components representing the framework of chaperone system. HSP60 plays a myriad number of roles like chaperoning, thermotolerance, apoptosis, cancer, immunology and embryonic development. In this review we discussed briefly the general knowledge and focussed on HSP60 in terms of structure, regulation and function in various physiological and pathological conditions.

Entropy production analysis for vortex rope of a Francis turbine using hybrid RANS/LES method

The precessing vortex core in the draft tube of Francis turbine is investigated using entropy production method. The high-fidelity Delayed Detached Eddy Simulation (DDES) method with SST k-ω turbulence model is used to acquire the entropy dissipative components of the flow, and the Q-criterion is selected to evaluate the vortex cores inside the draft tube under different operating conditions, separately. The results show that the numerical simulation is in good agreement with the experimental data obtained from the model test. It is found that the vortex motion, separation flow and shock phenomenon are considered to be hydrodynamic factors for the formation of entropy. Furthermore, draft tube accounts for the greatest proportion of entropy production, which is ascribed to the vortex rope. Vortex rope will rotate in the same direction as the runner, but the rotational speed is lower, resulting in low frequency pressure pulsation with large amplitude in the draft tube. It is concluded that the key reason why great energy dissipation is caused in the draft tube is that the vortex rope is transporting continuously towards the downstream, especially when the turbine deviating from optimum operating point.

Comparative investigation of ultrafast thermal shock of Ti3AlC2 ceramic in water and air

AbstractIn this work, ultrafast thermal shock of Ti3AlC2 ceramic was evaluated in water and air by utilizing the induction heating method. First, the annealed samples were heated to the set temperature in tens of seconds and dropped into the cooling water within 0.1 s which is rather short not to degrade the sample temperature. Compared to the traditional thermal shock method when quenching in water, the abnormal thermal shock phenomenon did not occur, which is owing to that no dense oxide layers were formed on the samples’ surface to act as the thermal barrier. The continuous decrease in residual flexural strength when quenched in water is associated with water infiltration, chemical reaction, and large surface tensile stress. The residual strength has 27.25 MPa upon 1250°C. Second, at the same testing temperature, the residual flexural strength when quenched in air maintains a high value of 388 MPa up to 1400°C. Dense oxide scales existed on the quenched surface of Ti3AlC2 samples. The results exhibit that Ti3AlC2 ceramic possesses excellent thermal shock resistance in water and air, suitable to be applied in extreme environments.