Theoretical Mode Research Articles

Influencing Factors of Adult College Student Satisfaction—Study Based on Grounded Theory

With the idea of lifelong education being developed, schools as the main platform of education, should pay more attention to the students satisfaction and better meet the society’s demand for talents. Taking adult colleges students in Beijing as the research object, the influencing factors of adult college students satisfaction(ACSS) has been analyzed, using qualitative research method through open coding, spindle coding and selective coding, and establishes a theoretical mode. The study of the influencing factors contribute to adult educational institution to better understand the students’ needs for education quality, and provide useful reference for the improvement of adult education service quality.

PENGARUH KUALITAS PESAN IKLAN SMARTPHONE SAMSUNG TERHADAP NIAT BELI DENGAN CITRA MEREK SEBAGAI VARIABEL PEMEDIASI

This research aims to examine the effect of quality of the advertising message to the buying intention and mediated by brand image. Subjects are people who use Samsung mobile in Yogyakarta. In this study developed a theoretical mode of the proposed four hypotheses to be tested using Structural Equation Model (SEM) by AMOS software 18. This research was conducted by distributing questionnaires to survey 150 respondents. Respondents were obtained through purposive sampling tehnique, the respondents were selected based on certain goals established researcher. The results of this study show that quality of the advertising message has positive effect to brand image, brand image has positive effect to buying intention, quality of the advertising message has positive effect to buying intention and brand image can partially mediated the positive effect of quality of advertising message toward buying intention.

Theories of change in sustainability science: Understanding how change happens

Science-based initiatives generate particular changes towards sustainable development. But why and how does this work? Theories of change (ToCs) can help in understanding the theoretical assumptions and modes of knowledge production associated with these initiatives: ToCs trigger debate among the stakeholders and evaluators of an initiative regarding the hypothesized and observed effects of actions as well as regarding underlying assumptions about how change happens. Therefore, they can strengthen the effectiveness of research, practice, and education in sustainability science.

A new bond failure criterion for ordinary state-based peridynamic mode II fracture analysis

Peridynamics is a nonlocal theory, and it has been applied to a series of fracture problems based on its two main bond failure criteria: the critical stretch criterion and the critical energy density criterion. In this paper, a new criterion, the critical skew criterion, corresponding to the shear deformation, is for the first time proposed specifically for ordinary state-based peridynamic mode II fracture analysis. The necessity of the critical skew criterion is demonstrated by limitations and inaccuracy of the existing critical stretch and energy density criteria in theoretical and numerical mode II fracture analysis. The validity of the proposed critical skew criterion is illustrated by quantitative analysis of the captured behaviors of the typical mode II fracture tests. The results obtained by the critical skew criterion agree well with the benchmark data from the linear elastic theory, the virtual crack closure technique, and the Griffith’s theory in different aspects of analysis. A simplified formula of the bond energy density is also derived and verified, and it can serves as a fundamental tool in peridynamic fracture analysis.

Semi-closed T-shaped-disk waveguide filter based on surface-plasmon-induced transparency

Filter is the core communication device in optical integrated chip. In recent years, plasma-induced transparency in surface plasmon (SPP) subwavelength waveguide photonic deviceshas become a research hotspot in the field of nano optics. The plasmon-induced transparency (PIT) is a phenomenon that the original absorption region produces a sharp transparent window due to the interaction among different resonant modes of SPPs, therefore, a higher resolution and quality factor surface plasmons can be obtained by using this feature to design a metal-medium-metal (MIM) waveguide structure filter. However, due to the Ohmic loss caused by metal parts, further research is needed on how to effectively improve transmission efficiency and achieve better frequency selection and filtering effect while reducing filter bandwidth in MIM waveguide filter. Based on the transmission and coupling characteristics of SPPs, an MIM waveguide filter with semi-closed T-waveguide side coupled disc cavity is proposed.Its transmission characteristics are studied by using the finite element method. The results show that a narrow-band transmission peak based on plasma-induced transparency appears in the transmission spectrum. Through theoretical analysis and mode field distribution, the physical mechanism of generating the PIT transparent peak and valley values on both sides is effectively explained. Compared with the traditional straight waveguide structure, the curved waveguide structure can generate the bilateral coupling effect, which can make resonant interaction stronger. Meanwhile, the numerical study shows that the approximately linear adjustment of filter wavelength can be achieved by changing the length of branches, the radius of the disk cavity and the refractive index of the medium in the cavity through external modulation. Further, the gain medium is embedded in the disk cavity, which enhances its local ability to emit light, strengthens the mode resonance effect, and realizes the compression filter pass-band bandwidth while effectively improving the structural transmittance, compared with similar filters. The research results provide an effective theoretical reference for designing the high resolution narrowband filter.

Mutual Interference and Coupling Response of Multicylinder Vibration among Combine Harvester Co‐Frame

Unbalanced vibrations of axial threshing cylinders on a combine harvester were coupled to each other through a frame. The intensified unbalanced vibration will shorten the working life of the axial threshing cylinder. In this paper, the theoretical modes of the axial threshing cylinder were carried out by using finite element analysis software ANSYS. The axis trajectory and speed fluctuation of the axial threshing cylinder under no‐load state and threshing state were tested and analyzed. According to the amplitude and axis trajectory of the transmission shaft, as well as the variation law of the axial threshing cylinder speed, the influence of rice straw on the vibration under the threshing state was revealed. The rotation speeds of cylinder I and cylinder III were adjusted, and the amplitude of cylinder II transmission shaft was analyzed when cylinder II was under stable condition. Then the disturbance and coupling relationships among the unbalanced vibration of axial threshing cylinders were compared. Test results showed that the rotational frequency of the axial threshing cylinder was not in its resonance interval at rated speed. When the axial threshing cylinder was threshing, the horizontal amplitude increased by 0.366 mm. The vertical amplitude increased by 0.697 mm. The speed decreased from 763 rpm to about 750 rpm. The rotational frequency of the axial threshing cylinder would not cause the resonance. With the feeding of rice, the amplitude of the axial threshing cylinder increased slightly and the operating speed was lower than the rated speed. The unbalanced vibration of the axial threshing cylinder transmitted along the frame and coupled with each other, causing the vibration of the axial threshing cylinder to be intensified.

Cruising queer, old Joburg

The article presents a queer reflection on the method of Walter Benjamin in Johannesburg, South Africa. Using a critical method of ephemera collection and collage, it offers a layered and provocative map of the city before the end of apartheid and at the beginning of the AIDS epidemic. The notion of “cruising,” an anachronistic theoretical mode, is applied to one iconic club, the Dungeon. Through archival research, oral histories with elder gay and lesbian Johannesburg residents, and personal reflection and cruising anecdotes, the article reflects on the process of queer archival work.

AGAINST AUTONOMY: WHY PRACTICAL REASON CANNOT BE PURE

The perennial appeal of Kantian ethics surely lies in its conception of autonomy. Kantianism tells us that the good life is fundamentally about acting in accordance with an internal rather than an external authority: a good will is simply a will in agreement with its own rational, self-constituting law. In this paper, I argue against Kantian autonomy, on the grounds that it excessively narrows our concept of the good, it confuses the difference between practical and theoretical modes of knowing the good, and it cannot respect the essential efficacy of the principles of practical reason.

Generating high-power asymmetrical Laguerre-Gaussian modes and exploring topological charges distribution.

We employ an off-axis pumped Nd:YVO4 laser and control the reflectance of output coupler to directly generate asymmetrical Hermite-Gaussian (HG) modes with various transverse orders. By using an astigmatic mode converter, the generated asymmetrical HG modes are straightforwardly transformed into asymmetrical Laguerre-Gaussian (LG) modes with a crescent-like shape. The average output power of all the crescent-shaped LG modes can exceed 1W at the pump power of 4W. Furthermore, experimental results are theoretically verified by resonant modes derived from the inhomogeneous Helmholtz equation with the localized source distribution. Theoretical resonant modes are also used to explore the dependence of the phase structures of LG modes on the system loss. As the loss increases, it is found that the singularities at the origin will be rearranged and new singularities are formed in the outside region with average orbital angular momentum remaining unchanged.

An evaluation of the failure modes transition and the Christensen ductile/brittle failure theory using molecular dynamics

The Christensen ductile/brittle failure theory can be interpreted in terms of the associated failure modes, those of shear bands and voids nucleation. Their conjunction is then termed as the failure modes transition and it is studied here using molecular dynamics. The test material is taken as a particular metallic glass, CuZr. First the theoretical failure criteria are evaluated and then the theoretical failure modes transition is evaluated. Both are found to perform extremely well. The overall failure theory contains three modes of failure, the two already mentioned plus a fracture criterion. A general conclusion from the work is that the voids nucleation criterion is of unusually broad relevance. Voids nucleation leads to voids growth and then further deteriorating mechanisms and ultimately failure. But the voids nucleation is the precipitating event of all that subsequently occurs in this process. Access to these capabilities is gained through the failure theory for all homogeneous, full density, isotropic materials. Only two standard testing measurements are needed to calibrate the entire failure theory, including the transitions.

Estimating the Theoretical and Empirical Probability Coefficients of Oil Pipeline Transport Infrastructure Failure Modes in Nigeria’s Coastal Ecosystem: Panacea for Non Optimal Deployment of Pipeline Safety and Security Management Systems

Abstract Failure of oil pipeline transport infrastructure in Nigeria’s coastal ecosystem has continued to pose serious environmental problems with consequent economic effects. This study estimated the theoretical and empirical probabilities oil pipeline infrastructure failure modes in Nigeria. Historical research design approach was used in which time series data of 10 years on Nigeria’s coastal oil pipeline infrastructure failure modes were obtained from the Nigerian National Petroleum Corporation. The statistical method of probability theory was used to determine the theoretical and empirical probabilities of oil pipeline infrastructure failure modes in order to optimally deploy pipeline safety and security management strategies. It was found that pipeline infrastructure failure by Vandalism poses the highest empirical probability and risk of occurrence.

A Novel Dynamic Method to Improve First-order Natural Frequency for Test Device

Abstract It is important to improve the natural frequency of test device to improve measurement accuracy. First-order frequency is basic frequency of dynamic model, which generally is the highest vibration energy of natural frequency. Taking vector force test device (VFTD) as example, a novel dynamic design method for improving first-order natural frequency by increasing structure stiffness is proposed. In terms of six degree-of-freedom (DOF) of VFTD, dynamic model of VFTD is built through the Lagrange dynamic equation to obtain theoretical natural frequency and mode shapes. Experimental natural frequency obtained by the hammering method is compared with theoretical results to prove rationality of the Lagrange method. In order to improve the stiffness of VFTD, increase natural frequency and meet the requirement of high frequency test, by using the trial and error method combined with curve fitting (TECF), stiffness interval of meeting natural frequency requirement is obtained. Stiffness of VFTD is improved by adopting multiple supports based on the stiffness interval. Improved experimental natural frequency is obtained with the hammering method to show rationality of the dynamic design method. This method can be used in improvement of first-order natural frequency in test structure.

An analytical study of sound transmission through stiffened double laminated composite sandwich plates

The main objective of this research work is focused on sound transmission loss analysis of stiffened double laminated composite sandwich plate structures subjected to plane sound wave excitation, wherein the laminated composite plates are composed of perfectly bonded functionally graded carbon nanotubes (CNTs) reinforced composite layers, and in each layer, the carbon nanotubes is uniform or functionally graded along with the thickness direction of structures, and three types of the CNTs distributions are studied. The extended rule of mixture is employed to determine the properties of the composite material. The compatibility of displacements on the interface between the plate and the stiffeners is employed to derive the governing equation of each stiffener. Then fluid–structure coupling is considered by imposing velocity continuity condition at fluid–structure interfaces. By using the space harmonic approach and virtual work principle, the sound transmission loss is described analytically. Since no existing results of sound insulation can be found for such composite material plate structure, comparison studies can only be made with the isotropic and laminated case. Good agreement is found from these comparison studies. Based on the developed theoretical mode, the influences of the volume fractions of CNTs, distribution type of CNTs, structural damping, lamination angle and the number of layers on sound transmission loss are subsequently presented.

Theoretical Calculation of the Geometry and Vibrational Frequencies of Triphenylmethane

Raman spectra of polycrystalline triphenylmethane (TPM) are recorded at room temperature in the range 4000–400 cm–1. The optimum structure and vibrational (Raman and IR) spectra of TPM are calculated using the B3LYP/6-311G(d,p) approximation. Theoretical modes and bands corresponding to them in the experimental Raman spectrum are assigned to stretching and bending vibrations of certain bonds in the TPM molecule based on visualization of the vibrations. Most bands, in particular, the strongest ones in the Raman spectra of TFM, are due to vibrations in monosubstituted benzene rings. Some of the theoretical modes and the corresponding experimental bands are assigned to benzene modes in Wilson notation.

Electrodeposition Kinetics of Ni/Nano-Y2O3 Composite Coatings

Ni/nano-Y2O3 composite films were successfully prepared by electrochemical deposition using an acid sulfamate bath. The influence of solid particles added to electrolyte on electrodeposition was investigated by electrochemical measurement methods. The linear sweep voltammetry test showed that the composite deposition took place at a greater potential than that of nickel, and the presence of nano-Y2O3 decreased cathodic polarization. Chronoamperometry studies indicated that the nucleation model of both deposits similarly approached the theoretical instantaneous nucleation mode based on the Scharifker–Hills model. The Y2O3 particles adsorbed on the cathodic surface were shown to facilitate the nucleation/growth of the nickel matrix which is consistent with the deposition kinetics parameters calculated by non-linear fitting experimental curves. The results of electrochemical impedance spectroscopy showed that the presence of Y2O3 particles in a bath is beneficial for the decrease in charge transfer resistance in the deposition. The atomic force microscopy observations of both deposits obtained in the initial electrodeposition stage confirmed that the Ni-Y2O3 composite had a higher grain number and finer mean grain size.

Crystal structure of phospholipase A2 in complex with 1-naphthaleneacetic acid.

Phospholipase A2 (PLA2 ) is one of the rate limiting enzymes involved in the production of arachidonic acid, a potent inflammatory mediator. PLA2 is widely distributed all over the animal kingdom. It is also seen in inflammatory exudation and venoms of different organisms. The studies demonstrated that PLA2 inhibitors have broad spectrum activities that they can either be used against inflammation or envenomation. In this study, the inhibitory activity of 1-napthaleneacetic acid (NAA) against porcine pancreatic PLA2 has been explained through isothermal titration calorimetry and enzyme kinetics studies. The atomic level of interactions of NAA with PLA2 was also studied using X-ray crystallography. Apart from these findings, the theoretical binding affinities and mode of interactions of two naphthalene-based NSAIDs such as naproxen (NAP) and nabumetone (NAB) were studied through molecular modeling. The studies proved that the selected ligands are binding at the doorway of the active site cleft and hindering the substrate entry to the active site. The study brings out a potential scaffold for the designing of broad spectrum PLA2 inhibitors which can be used for inflammation or envenomation. © 2018 IUBMB Life, 70(10):995-1001, 2018.

Recent progress on piezoelectric energy harvesting: structures and materials

With the rapid development of advanced technology, piezoelectric energy harvesting (PEH) with the advantage of simple structure, polluted relatively free, easily minimization, and integration has been used to collect the extensive mechanical energy in our living environment holding great promise to power the self-sustainable system and portable electronics. In this paper, attempts have been made to review the progress of piezoelectric materials and devices used for energy harvesting. The review focused on three parts: structure of piezoelectric devices (cantilever, cymbal, and stacks); theoretical mode, including vibration mode (d31 and d33) and its responding theories of different devices; and piezoelectric materials, among which the electric performance of Pb(ZrTi)O3-based, lead-free-based, and composites applied in bulk/micro/nano-PEH devices were introduced in details. It is suggested that a new structure of PEH should be designed by combining advantages of cantilever, stacks, and cymbal structure. Besides, high d33 × g33 value and low e of piezoelectric materials are required in order to generate high electric output power for bulk/micro/nano-PEH. Additionally, lead-free piezoelectric ceramics is a candidate for manufacturing PEH devices, and nano-composite materials should be developed to further improve the flexibility of piezoelectric materials.

Experimental (FT-IR, Laser-Raman and NMR) and theoretical comparative study on 2-benzylsulfanyl-4-pentyl-6-(phenylsulfanyl)pyrimidine-5-carbonitrile, a potential bioactive agent

In this paper, the experimental and theoretical vibrational frequencies of a potential bioactive pyrimidine derivative molecule named 2-benzylsulfanyl-4-pentyl-6-(phenylsulfanyl)pyrimidine-5-carbonitrile has been investigated. The experimental FT-IR and Laser-Raman spectra of the studied molecule are in the region (4000–400[Formula: see text]cm[Formula: see text] and (4000–100[Formula: see text]cm[Formula: see text], respectively, in gas phase. The vibrational modes and optimized ideal structure parameters(bond lengths, bond angles and selected dihedral angles) were calculated by using DFT/B3LYP, DFT/BHandHLYP and DFT/PBE1PBE methods with 6-311[Formula: see text]G(d,p) basis set. The theoretical mode assignments have been obtained by using potential energy distribution (PED) with the VEDA4 software program. Additionally, infrared and Raman intensities, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and their clouds, and other related molecular properties were calculated and evaluated. The proton (1H) and carbon-13 ([Formula: see text]C) nuclear magnetic resonance (NMR) chemical shifts have been investigated for the title molecule, both experimentally (in DMSO-d[Formula: see text] and theoretically (in vacuum and DMSO). The thermodynamic properties of the tile compound have been investigated using the mentioned theoretical computational methods. The results revealed that there isgood agreement between experimental and theoretical results and these results have supported the related literature.

Investigation on critical heat flux of flow boiling in parallel microchannels with large aspect ratio: Experimental and theoretical analysis

Critical heat flux (CHF) for microchannel heat sink makes significant sense to industrial applications in preventing thermal safety accidents and avoiding facility burnout. Nevertheless, the fundamentals of CHF in confined microchannels are lack of clear comprehension, and related visualization experimental data about CHF also needs complement. The present work explores flow boiling CHF in parallel shallow microchannel heat sink with visualization experiments, aiming to provide new CHF data for microchannels with large aspect ratio (AR = W/H = 5). Two test configurations (S1: H = 400 μm, W = 2000 μm, S2: H = 300 μm, W = 1500 μm) and two kinds of working fluids (ethanol and acetone) are adopted. By capturing bubble behaviors with high speed photography, the characteristics and mechanism of CHF for such shallow microchannels are revealed. It is found out that the boiling curve keeps a linear growth with the wall superheating degree after the local dry-out, where the dominate heat transfer mechanism directly transits to the film boiling without experiencing the transition boiling. Meanwhile, the effect of mass flux, working fluid, and hydraulic diameter of channel on the CHF is also studied respectively. The experimental results illustrate that the CHF in the microchannels with large AR is significantly influenced by flow instability and presents a third order polynomial increasing trend with G. Besides, statistic analysis on the CHF data with some well-known correlations is conducted to find out the suitable theoretical mode for the shallow microchannels. A new CHF correlation that can especially fit for the microchannels with aspect ratio heavily deviated from 1 is proposed, where 116 data points involving 8 different working fluids and 9 types of microchannels are verified with MAE of 7.3%.

Enhancing mechanisms education through interaction with augmented reality simulation

AbstractComputer simulation has been used pervasively to help students understand deeply and visually the theoretical bases of mechanisms. This paper proposes an AR mechanism education system (ARMES) to provide a tool that can conduct mechanism simulations with high level of interaction, easy modeling, and simulation environment and working on real mechanisms. The system consists of theoretical lecture mode and practical exercise mode. Theoretical lecture mode adopts the basic theories of mechanisms from the book Mechanisms and Machine Theory (MMT) and provides an interactive learning style for users via an interactive tool. Practical exercise mode allows modeling, simulation, kinematical characteristics analysis, dynamic analysis, and synthesis based on the interaction with the information that has been rendered on a real mechanism via the interaction tool. In addition, the modeling is based on markers, making the system easy for novice learners to use. The simulation is based on geometrical concepts, making the geometrical bases of mechanism theories clear for users to understand. The evaluation of the system is conducted with 20 participants and a survey. The results reveal that by exploiting the characteristics of AR, the system is helpful in improving the interaction, visualization, and practicality of the mechanism problems. These features will make the system a powerful tool for the teaching of mechanisms.