Principle Of Conversion Research Articles

A plausible mechanism in premicellar aggregates for photocurrent generation in photogalvanic cell for simultaneously solar power conversion and storage

Photogalvanic (PG) cells are the only solar cell that can convert and store solar energy simultaneously. The PG cell is based on the diffusion of electrolytes (dye, reductant, alkali/acid and surfactant). We have completed photogalvanic study for the four (BCB-fructose, BCB-AA, MB-fructose and MB-AA) redox systems without and with SDS, CTAB and tween 80 surfactant in our previous research work. The results show that the most efficient system is MB-AA-SDS, in which methylene blue (MB) as a photosensitizer, ascorbic acid (AA) as reductant, and sodium dodecyl sulphate (SDS) as anionic surfactant is used. Since, to make an efficient cell, it is very important to understand the mechanism part. Consequently, the aim of this paper is to provide information about the basic difference of photocurrent generation in PV, DSSC and the PG cell, a plausible mechanism for the generation of electricity in the PG cell having MB, AA and SDS, and also give mechanism for stabilization of MB molecules in premicellar region of SDS on the basis of findings of our previous research work and literature study. For the same, first, made a comparative study for generation of electricity in PV, DSSC and the PG cell, then the most possible mechanism for photocurrent generation in PG cell and lastly mechanism for solubilization and stabilization of the MB molecules by SDS have been given. The comparative study of different solar cells shows that the basic principle for conversion of solar to electrical energy is same for all solar cells. The main difference is in the place of chemical reactions which occur on the surface of the electrode in solar cells while in the PG cells, it occurs inside the electrolytic solution. The AA/ascorbate ion and the base form of the MB are stabilized by premicellar aggregates of SDS, this helps to solubilize the MB molecules by providing an ordered way and enhancing the number of MB molecules for absorption of light in the PG cell. This ultimately enhances the number of leuco forms of MB which leads to an increase in the number of electrons in the external circuit of the PG cell. Thus, by understanding the most plausible mechanism one can make a PG cell in which the compatibility of surfactant is maximum with a dye-reductant system for photocurrent generation and storage, simultaneously. Further, it provides basic ideas about conditions and parameters which are responsible for the better electrical output of the PG cell. This may make the cell practically viable for daily life in the future.

Performance analysis of biomass driven thermophotovoltaic system from energy and exergy perspectives

• Propose a thermo-physical model of biomass-TPV and conduct a parametric analysis. • Present biomass-TPV/T concept for photo-thermal energy cascade conversion. • Effect of fuel and combustion design is analyzed from energy and exergy perspectives. • Increasing the TPV area and the regenerator design improves efficiency by more than 10%. • Provide reference for the design of TPV power device driven by fuel combustion. The new thermophotovoltaic (TPV) technology driven by biomass fuel is an important way of solar indirect use, it can directly convert thermal energy into electrical energy through thermal radiation; and it is more suitable for the cascade utilization of energy when compared to direct solar-TPV. Therefore, to identify the principles of energy conversion within the biomass-TPV, this study conducted a thermodynamic analysis of a biomass-TPV power device from energy and exergy perspectives. A thermo-physical model of TPV verified by experimental data was established. The concept of biomass-thermophotovoltaic/thermal (TPV/T) combined conversion was summarized to achieve cascade utilization. Particular consideration is given to the effects of biomass fuels, combustion chamber designs and selective filters on the thermodynamic performance of biomass-TPV device and biomass-TPV/T conversion. The results show that the largest exergy loss of biomass combustion accounts for 40%. The biomass fuel moisture increases the exergy losses in combustion and flue gas and thus reduces TPV efficiency by more than 3 percent points. Increasing the TPV area and the regenerator design are beneficial for reducing the exergy loss of flue gas and improving TPV efficiency by more than 10 percent points. Narrow-band filters decrease the exergy losses of TPV emitter and cell, while increasing the loss in flue gas. The narrow-band filter is more suitable for TPV/T combined conversion. This study provides a reference for the design and optimization of biomass-driven TPV conversion system.

An improved parallel five-level reinjection CSC for self-commutation of thyristor converter

PurposeThis paper aims to study a multi-level reinjection current source converter (MLR-CSC) that adds attracting properties such as the self-commutation and pulse multiplication to the thyristor converter, which is of great significance for increasing the device capacity and reducing current harmonics on the grid side. Particularly, designing advantageous driving methods of the reinjection circuit is a critical issue that impacts the harmonic reduction and operation reliability of the MLR-CSC.Design/methodology/approachTo deal with the mentioned issue, this paper takes the five-level reinjection current source converter (FLR-CSC), which is a type of the MLR-CSC, as the research object. Then, a method that can fully use combinations of five-level reinjection switching functions based on the concept of decomposition and recombination is proposed. It is worthy to mention that the proposed method can be easily extended to other multi-level reinjection circuits. Moreover, the working principle of the three-phase bridge circuit based on semi-controlled thyristors in the FLR-CSC that can achieve the four-quadrant power conversion is analyzed in detail.FindingsFinally, the simulation and experimental results of FLR-CSC verify the effectiveness of the proposed reinjection circuit driving method and the operating principle of four-quadrant power conversion in this paper.Originality/valueThe outstanding features of the proposed driving method for FLR-CSC in this paper include combinations of reinjection switching functions that are fully exploited through three simple steps and can be conveniently extended to other multi-level reinjection circuits.

Implementation of Circular Business Models for Olive Oil Waste and By-Product Valorization

Mediterranean olive oil producers have multiple incentives for adopting circular business models and better resource management, facing water scarcity and huge amounts of waste, but also seeing new opportunities for value creation. This article aimed to understand how circular business models valorizing olive oil waste and by-products are implemented. Ten business cases from six Mediterranean countries were studied, mainly based on semi-structured interviews with enterprise managers. Data were analyzed according to the business model canvas elements, success factors, and barriers while considering the institutional context. The results highlight the diversity of activities, types of resources used, and partnerships and products offered in different market segments. The principles of biowaste conversion and circularity, such as cascading, upcycling, recycling, and recovering, are all applied. The key success factors comprise an environmental concern, knowledge about biotechnologies, markets and logistics, a long-term commitment to the sector, local availability of resources, legislation, subsidies, and product acceptance by consumers. The main barriers include a lack of specific public financial support, an insufficient knowledge transfer from research to olive oil producers, and a lack of articulation of needs for research by the enterprises. More public-private collaborations and multi-stakeholder projects are needed for further shifting to a circular economy in the olive oil sector.

Recent Progress in Flexible Pressure Sensor Arrays.

Flexible pressure sensors that can maintain their pressure sensing ability with arbitrary deformation play an essential role in a wide range of applications, such as aerospace, prosthetics, robotics, healthcare, human–machine interfaces, and electronic skin. Flexible pressure sensors with diverse conversion principles and structural designs have been extensively studied. At present, with the development of 5G and the Internet of Things, there is a huge demand for flexible pressure sensor arrays with high resolution and sensitivity. Herein, we present a brief description of the present flexible pressure sensor arrays with different transduction mechanisms from design to fabrication. Next, we discuss the latest progress of flexible pressure sensor arrays for applications in human–machine interfaces, healthcare, and aerospace. These arrays can monitor the spatial pressure and map the trajectory with high resolution and rapid response beyond human perception. Finally, the outlook of the future and the existing problems of pressure sensor arrays are presented.

Second and Outer Coordination Sphere Effects in Nitrogenase, Hydrogenase, Formate Dehydrogenase, and CO Dehydrogenase.

Gases like H2, N2, CO2, and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N2, CO2, and CO and the production of H2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N2 fixation by nitrogenase and H2 production by hydrogenase as well as CO2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.

Design and Experiment of Piezoelectric–Electromagnetic Composite Energy Trap Based on Human Motion

To realize the harvesting of energy generated by human movement, in this study, a piezoelectric–electromagnetic composite was designed for harvesting the energy generated by low-frequency human motion is designed by combining the principle of power generation and electromagnetic energy conversion of polyvinylidene fluoride (PVDF) piezoelectric materials. First, the structure and working principle of the piezoelectric–electromagnetic composite energy trap were designed and analyzed. Next, the system dynamics model of piezoelectric–electromagnetic coupling power generation was established, and the main influencing factors of the composite energy trap were derived. Moreover, the influence of PVDF piezoelectric materials with different size parameters on the output voltage and the influence of the frequency of the moving permanent magnet on electromagnetic power generation were analyzed. Finally, the prototype was constructed and tested. The results revealed that the output voltage of the piezoelectric–electromagnetic composite energy trap placed horizontally is higher than that of the composite energy trap placed vertically at step frequencies of over 90 steps/min, and the maximum output voltage is 25.6 V at the step frequency of 140 steps/min. The electric energy generated by the composite energy trap can supply power to low-power electronic devices, thus demonstrating the feasibility of collecting human-motion energy for power generation.

The use of sports-oriented technologies in the applied occupational training of students

The paper examines the use of sports-oriented technologies in the applied occupational training of students. It was noted that sports-oriented physical education of students is based on the principles of conversion of sports training and free choice of a sport discipline that contributes to the development of personal physical culture of the student. The concept of “sports-oriented technologies” was defined as a goal-oriented activity of students in focused on achieving maximum sports performance, which has a positive effect on their physical and mental condition and social relations.
 It was indicated that the advantages of sports-oriented physical education include taking into account the students’ personal interests, the ability to choose a sport, which can be practiced both in curricular activities and independently during their leisure time. When developing sports-oriented technology, we proceeded from the premise that technology means an algorithmic sequence of actions aimed at achieving the planned result in a timely manner at an optimal cost. The sports-oriented program for students of the main department was characterized, which aimed at in-depth study of certain sports and modern motor systems, that allows to obtain results from the type of activity under the conditions of competitions and control tests, as well as to assess the abilities and to develop a strong need for regular sports training. The structure of the technological process was determined, which includes: the goal, objectives, principles, content, form, methods, means of achieving the goal, resource provision, goal adjustment, final results, and efficiency criteria. The result of this process is the program and its content. The structure and content of the program included traditional approaches to design. It was stated that the evaluation of the efficiency of the developed program was carried out in accordance with the efficiency criteria suggested by experts and with the approaches recommended in the program documents to assess the specific physical preparedness of students.

Potential for Energy Utilization of Air Compression Section Using an Open Absorption Refrigeration System

In this paper, an open absorption refrigeration system is proposed to recover part of the waste compression heat while producing cooling capacity to further cool the compressed air itself. The self-utilization of the compression waste heat can significantly reduce the energy consumption of air compression, and hence increase the energy efficiency of the cryogenic air separation unit. To illuminate the energy distribution and energy conversion principle of the open absorption refrigerator-assisted air compression section, a thermodynamic model is built and the simulation work conducted based on a practical triple-stage air compression section of a middle-scale cryogenic air separation unit. Our results indicate that the energy saving ratio is mainly constrained by the distribution of the cooling load of compressed air, which corresponds to the heat load of the generator and cooling capacity of the evaporator in the open absorption refrigerator. The energy saving ratio ranges from 0.52–8.05%, corresponding to the temperature range of 5–30 °C and humidity range of 0.002–0.010 kg/kg. It is also estimated, based on the economic analysis, that the payback period of the open absorption refrigeration system is less than one year, and the net project revenue during its life cycle reaches USD 5.7 M, thus showing an attractive economic potential.

Research on NCFCP compact broadband NIR detector imaging and energy transfer function.

Nonlinear crystal frequency conversion imaging with direct detection by silicon-based detectors is an effective way to break through the limitations for existing near-infrared (NIR) detectors with expensive cost and high noise. In this paper, a broadband NIR detector imaging scheme based on the principle of nonlinear crystal frequency conversion (NCFCP) was proposed. A thin film of nonlinear crystal frequency conversion material (NCFCM) combined with a silicon-based detector was used to form a broadband NIR detector. The theoretically investigated energy transfer function was used as a guidance for experiment. Meanwhile, the relationship between the imaging effect and the energy transfer of the NCFCP-based compact broadband NIR detector in the NIR band was measured experimentally. The accuracy of the theoretical study had been verified by the measured transfer results.

A New Method of Seismic Source Parameter Estimation of a Locked-Segment Cracking Event

Locked segments are widely present in the slip surface of large rock slopes and seismogenic faults of rock underground engineering. Each cracking occasion of the locked segment results in a seismic event. Accurate determination of the seismic source parameters of a locked-segment cracking event is crucial for the reliable evaluation of rock-mass stability associated with slopes and underground openings. The theoretical framework for calculating seismic source parameters in previous studies is mostly based on the stick-slip model, which is not applicable to describing the locked segment’s damage process, and research on seismic source parameter estimation of a locked-segment cracking event is insufficient. Hence, based on the principle of energy conversion and distribution during the locked segment’s damage process, we proposed an equation for the radiated seismic energy of a locked-segment cracking event. Using this equation, we established a mechanical relationship between the earthquake magnitude and the stress drop or shear strain increment (or maximum coseismic displacement) of a locked-segment cracking event. Typical case studies of rock slope and rock underground engineering showed that the proposed calculation method of seismic source parameters was reliable. In addition, this paper discusses the controversy surrounding the relationship between earthquake magnitude and stress drop. Relevant results lay a firm physical foundation to accurately calculate the seismic source parameters of a locked-segment cracking event and obtain detailed insights into the generation mechanism of the locked-segment cracking event.

Non-horizontal target measurement method based on monocular vision

With the development of computer vision technology, target measurement methods have been widely used in robot automatic obstacle avoidance, vehicle-assisted driving and other systems. There are many target measurement technologies available, but most of them are based on binocular or trinocular vision, or based on monocular vision with other auxiliary equipment, or based on monocular vision to measure horizontal target. The first two technologies achieve precise positioning by increasing the amount of data and sacrificing processing speed, while the third only studies the measurement method of the horizontal target. To address the complexity of the multi-equipment measurement methods and the limitation of the monocular measurement methods for horizontal target, this paper proposes a novel monocular vision measurement method for the non-horizontal target. According to the principle of camera imaging, internal and external parameters of the camera and analogue-to-digital conversion principle, the imaging relationship model for measuring the relative height and target distance of non-horizontal target is deduced, and the solvability of the model is demonstrated by mathematics. The experimental results verify the correctness and feasibility of this method.

Thermodynamic analysis of ideal thermocompressor based on Euler view

The thermocompressor is the driving source and the core heat-work conversion part of Vuilleumier (VM) refrigerator, which cause pressure fluctuation of the gas by converting the thermal energy at a constant volume. The thermocompressor is consists of cylinder, heater, generator, cooler, displacer, driving mechanism, load, hot cavity and cold cavity. Therefore, the ideal thermocompressor was introduced for thermal analysis to simplify the thermodynamic process and components. In order to better understand the principle of heat-work conversion in the ideal thermocompressor, firstly, the thermodynamic concept of the variable mass system that can be used in the ideal thermocompressor was introduced. Secondly, the thermodynamic process of the ideal thermocompressor under the Euler view was analyzed. Thirdly, the internal operation characteristics of the thermocompressor without load and driving displacer type refrigerator were discussed. At last, the distributions of enthalpy flow, entropy flow and exergy flow in all parts of the ideal thermocompressor were carried out. The results show that the thermocompressor does not output the net entropy flow to the load in one cycle and the flow exergy output by thermocompressor is equal in quantity to the acoustic power output by thermocompressor.

A CONVERSATION ANALYSIS OF CLASSROOM INTERACTION IN AN EYL CLASS BY USING UNO CARD

This article aims to determine the principles of conversation analysis contained in conversations between teacher and EYL students during class interactions in an EYL class using UNO cards and to find out how teachers apply the principles of conversation in an EYL class. This research uses descriptive qualitative in the form of conversation analysis. The participants involved in this study were one teacher and four EYL students with the research being conducted in one of the courses in Banjar. Research data were collected using two instruments, namely observation (non-participants observation) and interviews (semi-structured). The research findings were analyzed based on 4 machines of interactional structure practice, namely; (1) turn-taking, (2) sequence organization, (3) turn design, and (4) repair, show that the teacher dominates the conversation during classroom interactions. This makes the teacher the first pair part (FPP) followed by young learners as a second pair part (SPP). The results of the interview revealed that teachers must know every psychology that young learners have in order to know the condition of each student so that students' focus does not leave learning. It is also intended that teachers are able to provide appropriate stimuli and methods for young learners. The researcher concludes that the analyzed conversations between teachers and EYL students are in line with the basic principles of conversation analysis. For further researchers, it is hoped that they will be able to explore more broadly the analysis of conversations that occur in-class interactions.Keywords: Conversation Analysis, Classroom Interaction, EYL

A tunable circularly polarized antenna in THz regime

A transmissive type single layered tunable linear to circular polarization converter is realized by conglomerating both metallic and graphene patches on the same layer over a polyimide substrate. The tunability has been realized in the proposed metasurface by varying the chemical potential of the L-shaped graphene patches at the diagonal ends. Quadrature phase shift between the orthogonal components of the electric field is produced by the anisotropy caused by the double T-shaped copper patch. A tunable axial ratio (≤3 dB) bandwidth ranging from 2.57 to 3.06 THz is exhibited. To demonstrate the polarization conversion capability of the proposed tunable polarization converter (PC), a linearly polarized microstrip patch antenna (MSA) operating in the same frequency band has been designed and integrated with it. The radiated linearly polarized electromagnetic waves from the antenna get transformed into circularly polarized waves after passing through the PC. Thus, a circularly polarized antenna is realized whose 3-dB axial ratio bandwidth is tunable across 2.6–3 THz. The transmissive type PC has been placed 10 μm above the antenna to generate left-hand circularly polarized (LHCP) waves across a bandwidth of 400 GHz. The proposed simple structured linear to circular PC provides the advantage of dynamic regulation of the CP band without making any alteration in the physical structure of the antenna. Most of the reported CP antennas in THz range constitute graphene based radiating patches. They do not involve the use of metasurface for polarization conversion. For the first time, the PC integrated microstrip patch antenna has been analyzed in this work. The principle of polarization conversion has been numerically studied through full-wave simulations in CST.

Line-Frequency-Isolation Flexible AC-Link Converter Based on Direct AC-AC Choppers

Line-Frequency-Isolation Flexible AC-Link Converter based on direct AC-AC choppers (FACL) is a novel AC-AC power conversion device expected to realize voltage compensation and power flow control. Compared with traditional voltage source inverter (VSI)-based devices, FACL has no DC-link capacitors that lead to high equipment failure rate. First, this paper systematically introduces FACL. The power conversion principle of FACL is analyzed, and the output comparison between the unipolar and bipolar FACL is presented. Then a high-performance bipolar FACL is proposed. It eliminates the shortcomings of the existing FACL topologies, such as bidirectional switches, undesirable phase shift, and restricted output range. Additionally, for facilitating the control of FACLs, a variant of the conventional dq reference frame called DQ-ABC synchronous rotating reference frame (DSRRF) is adopted. DSRRF provides a platform for the flexible operation in the form of DC between two three-phase voltages, which is beneficial to FACL control. On the basis of DSRRF, the closed-loop control strategy of FACLs is designed so that the decoupling control and closed-loop control of the output voltage amplitude and phase can be achieved conveniently. Finally, the open-loop and closed-loop experimental tests are carried out based on a 1 kW experimental prototype to verify the theoretical analysis.

Energy, environment, and economic analyses on a novel hydrogen production method by electrified steam methane reforming with renewable energy accommodation

More and more attention has been paid to hydrogen due to its cleanity and high energy density. However, hydrogen production from conventional steam methane reforming has high CO2 emission and heat loss in the flue gas. Hydrogen from water electrolysis has the defects of high cost and low efficiency. Electrified steam methane reforming (E-SMR) process is proposed by integrating power to gas technology with steam methane reforming based on the principle of efficient electrothermal conversion and energy cascade utilization. Electrical equipment is used in the process to eliminate the above drawbacks and accommodate renewable electricity. The novel process is simulated by chemical equilibrium and mass-energy conservation methods and analyzed from energy, environment, and economy. The optimal performance of E-SMR processes is investigated by adjusting the steam carbon ratio and reforming temperature under appropriate pressure. The optimal thermal efficiency (97.27 %) is improved by 18 percentage points at least compared to current industrial steam methane reforming processes. The optimal electrical efficiency (88.68 %) is at least 11.48 percentage points higher than that of running commercial water electrolysis systems. The novel process achieves low carbon emission (even zero-emission with CCS) since the required reforming energy is electricity instead of combustion. The cost of the proposed process can be minimized to 2.47 $/kg H2 through economic analysis. This work may provide an efficient, low-carbon, and economical option for hydrogen production.

Pragmatic Profiles of Adults with Fragile X Syndrome and Williams Syndrome.

Linguistic phenotypes of individuals with Fragile X (FXS) and Williams (WS) syndromes exhibit various degrees of pragmatic impairment, involving difficulties in social communication and in adapting to conversational principles. The goal of the present study was to explore syndrome-specific pragmatic profiles of adults with FXS and WS based on the assessment of the observance of Gricean maxims of conversation. The participants were 12 Spanish-speaking adults (6 FXS/6 WS), without a diagnosis of ASD, whose extensive naturalistic conversations (71,859 words) were transcribed and coded with the CHILDES/TALKBANK tools and the PREP-CORP pragmatic protocol. Violations of the maxims of conversation were analyzed, and indexes of cooperation and conversational response were obtained. Both groups showed reduced verbal production and repetitive dysfluencies; prominent features in the FXS profile were higher proportion of non-contingent language, perseverations of topic and form, and impulsive conversational responses; in the WS profile, salient characteristics were higher proportion of tangential utterances, reformulations, and conversational responses reflecting overly literal interpretation. Pragmatic profiles of violation of conversational maxims reflect specific communication skills impaired in adults with FXS and WS and raise the need for assessment and intervention methods that specifically address their social communication abilities.

Monitoring and Performance Analysis of Seed Sowing Using Photoelectric Sensing

The seed sowing on-line monitoring system based on the principle of optical frequency conversion sensing is developed. The photoelectric flow sensor is used to design the photoelectric flow receiver and the photoelectric flow emitter. The system takes STM32F103ZET6 single chip microcomputer, step-down chip LM2576, and voltage comparator LM393AD as the core. On this basis, the slot wheel transcendental rotation and fast supplemental seeding method is adopted, namely, real-time miss-seeding monitoring and supplemental seeding for seed sowing. The laser photoelectric sensor (PS) is used to monitor miss-seeding. The Hall sensor is applied to monitor the rotation speed of the seeder in real time, and the corresponding supplemental seeding, speed monitoring, and miss-seeding monitoring modules are designed. When seed leakage occurs, the set light emitting diode (LED) alarm module will inform the system that supplemental seeding is needed, and the module corresponds to the seeding channel. In the experiment, the miss-seeding rate was reduced from 3.8% to 0.5% after the system adopted the supplemental seeding module, that is, the mechanical seed sowing needs supplemental seeding. Under the condition of automatic supplemental seeding, when the continuous missing seeds ≤3 and the time interval error ≤1.4%, the missing seeding rate ≤0.8%, so as to realize the non-deviation supplemental seeding. The accuracy of single seed monitoring is more than 98%, and the accuracy of seed sowing monitoring is 94.7%, which means that the designed seed sowing monitoring system has high monitoring accuracy.

Conversational Implicature Between Students in Deutsch Für Tourismus With Rollenspiel Technique

This research examined the violation of the principle of cooperative conversation with data sources from conversations among students in the course Deutsch für Tourismus with a learning model using the Rollenspiel teaching method. Besides aiming to describe and categorize forms of violation of the principle of cooperative conversation, this study also aimed to describe the types of conversational implicatures that arise from violations of the principle of cooperative conversation. The method used is a qualitative method with descriptive elaboration using the theory of the principle of cooperative conversation by Grice and the theory of conversational implicatures by Yule. Based on the analysis found 25 utterances containing violations of the principle of cooperative conversation. Violations of the principle of cooperative conversation include violations of the maxim of quantity with 8 data, violations of the maxim of quality with 6 data, violations of the maxim of relevance with 8 data, and violations of the maxim of manner with 3 data. The conversations among students, it contains often more information than is needed and does not provide relevant contributions. Three types of conversational implicatures arise from the violation of the principle of cooperative conversation, namely: 5 types of general conversational implicatures, 2 types of scaled conversational implicatures and the dominant ones are the specific conversational implicatures with a total of 21 because the conversations among students occur often requires special knowledge in understanding the context.