Evaluating the Effect of Optical Coupler in a 1.5KVA PWM Inverter

This paper presents the design and implementation of a 1.5KVA inverter system. The aim of the paper is to evaluate the effect of optocoupling technology on inverter system. The developed circuit compares the output load with the input voltage when 4N35 opto coupler is used and in the absence of it. Two different inverter systems were designed and the voltages at the output pins of Sg3524 were measured. It was observed that there seems to be fluctuation in the output voltage of the system without optocoupling and the voltage of the inverter keeps dropping till the system shuts down. The basic principle of the operation of the inverter is a simple conversion of 12V DC at a frequency of 50Hz to 230V AC. The result shows that optocoupling technique is essential part of an inverter system to achieve a good efficiency.

ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.

ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.

RANCANG BANGUN SISTEM PEMANFAATAN PANAS BUANG PADA KOMPOR PORTABEL MENGGUNAKAN THERMOELECTRIC GENERATOR

The world's population continues to grow, causing energy needs to increase rapidly.In fact, not all regions have a special supply of electrical energyareas that are located in remote and difficult to access places. Besides the depletion of reservesfossil fuels as the main source of electricity generation and effectsbad pollution also encourages the change of energy sources into new energyrenewable (EBT). The purpose of this research is to design a solution forovercome both of these by using the exhaust heat utilization system(waste-heat recovery) in domestic combustion, especially portable stoves.Thermoelectric generator (TEG) is the right choice because it has severaladvantages needed such as simple conversion process, reliabilityhigh, and ease of application. The research will discuss the design of the toolwaste-heat recovery on portable stoves mechanically and electrically. Designcarried out on 2 different types of TEG modules, namely TEP1-1264-3.4 and SP1848-27145. The proposed tool has an estimated output power of about 9.24 W for the moduleTEP1-1264-3.4 and 9.0048 W for SP1848-27145 module using 8a TEG module with an approximate temperature difference of 60 ? and a cooling systemwater based. Thus the TEP1-1264-3.4 module generates more powerhigher than SP1848-27145 module and the series configuration is rated better because of thishave no problem when experiencing voltage differences between modules. Designmechanical build that is made to have 2 separate frame parts for conveniencecircuit maintenance.

Expanding the Scope of the Cleavable N-(Methoxy)oxazolidine Linker for the Synthesis of Oligonucleotide Conjugates

Oligonucleotides modified by a 2′-deoxy-2′-(N-methoxyamino) ribonucleotide react readily with aldehydes in slightly acidic conditions to yield the corresponding N-(methoxy)oxazolidine-linked oligonucleotide-conjugates. The reaction is reversible and dynamic in slightly acidic conditions, while the products are virtually stable above pH 7, where the reaction is in a ‘‘switched off-state’’. Small molecular examinations have demonstrated that aldehyde constituents affect the cleavage rate of the N-(methoxy)oxazolidine-linkage. This can be utilized to adjust the stability of this pH-responsive cleavable linker for drug delivery applications. In the present study, Fmoc-β-Ala-H was immobilized to a serine-modified ChemMatrix resin and used for the automated assembly of two peptidealdehydes and one aldehyde-modified peptide nucleic acid (PNA). In addition, a triantennary N-acetyl-d-galactosamine-cluster with a β-Ala-H unit has been synthesized. These aldehydes were conjugated via N-(methoxy)oxazolidine-linkage to therapeutically relevant oligonucleotide phosphorothioates and one DNA-aptamer in 19–47% isolated yields. The cleavage rates of the conjugates were studied in slightly acidic conditions. In addition to the diverse set of conjugates synthesized, these experiments and a comparison to published data demonstrate that the simple conversion of Gly-H to β-Ala-H residue resulted in a faster cleavage of the N-(methoxy)oxazolidine-linker at pH 5, being comparable (T0.5 ca 7 h) to hydrazone-based structures.

An Analysis of Chinese American Literature from the Perspective of Cultural Translation

The rise and development of Chinese-American literature is closely related to the socio-cultural context in which the subject of its creation resides. Because the works contain a lot of Chinese elements, the writing of Chinese American literature often entails translation from the perspective of cultural studies. This kind of translation does not refer to the simple conversion on linguistic level, but the adaptation of Chinese culture, Chinese history and Chinese experience, which is a kind of invisible cultural translation. Chinese American writers have applied Chinese traditional culture to their works and achieved success in the target audience, which provides effective solutions and rich experience for the dissemination of traditional Chinese culture. This paper intends to study Chinese American literature from the perspective of cultural translations, and its enlightenment on the dissemination of traditional Chinese culture overseas.

Observed sizes of planet-forming disks trace viscous spreading

Context. The evolution of protoplanetary disks is dominated by the conservation of angular momentum, where the accretion of material onto the central star is fed by the viscous expansion of the outer disk or by disk winds extracting angular momentum without changing the disk size. Studying the time evolution of disk sizes therefore allows us to distinguish between viscous stresses or disk winds as the main mechanism of disk evolution. Observationally, estimates of the size of the gaseous disk are based on the extent of CO submillimeter rotational emission, which is also affected by the changing physical and chemical conditions in the disk during the evolution. Aims. We study how the gas outer radius measured from the extent of the CO emission changes with time in a viscously expanding disk. We also investigate to what degree this observable gas outer radius is a suitable tracer of viscous spreading and whether current observations are consistent with viscous evolution. Methods. For a set of observationally informed initial conditions we calculated the viscously evolved density structure at several disk ages and used the thermochemical code DALI to compute synthetic emission maps, from which we measured gas outer radii in a similar fashion as observations. Results. The gas outer radii (RCO, 90%) measured from our models match the expectations of a viscously spreading disk: RCO, 90% increases with time and, for a given time, RCO, 90% is larger for a disk with a higher viscosity αvisc. However, in the extreme case in which the disk mass is low (Mdisk ≤ 10−4 M⊙) and αvisc is high (≥10−2), RCO, 90% instead decreases with time as a result of CO photodissociation in the outer disk. For most disk ages, RCO, 90% is up to ~12× larger than the characteristic size Rc of the disk, and RCO, 90%/Rc is largest for the most massive disk. As a result of this difference, a simple conversion of RCO, 90% to αvisc overestimates the true αvisc of the disk by up to an order of magnitude. Based on our models, we find that most observed gas outer radii in Lupus can be explained using viscously evolving disks that start out small (Rc(t = 0) ≃ 10 AU) and have a low viscosity (αvisc = 10−4−10−3). Conclusions. Current observations are consistent with viscous evolution, but expanding the sample of observed gas disk sizes to star-forming regions, both younger and older, would better constrain the importance of viscous spreading during disk evolution.