Flash Tests Research Articles

Innovative design and field performance evaluation of a desert-adapted PV module for enhanced solar energy harvesting and reliability in harsh arid environments

The aim of this study is to present and evaluate the performance of a novel photovoltaic (PV) module configuration introduced as the “Desert Module,” developed to enhance the production and efficiency of PV power plants operating in harsh desert locations. This innovative module has been constructed by incorporating various technological solutions to address desert climate conditions such as high temperatures, soiling, and intense UV radiation. To assess the performance of the developed “Desert Module,” a comprehensive evaluation was conducted by comparing its performance to that of a conventional module. The study encompasses three main aspects: (i) indoor characterization, including flash and electroluminescence tests; (ii) performance assessment in a hot semi-arid climate over an eight-month period; and (iii) economic analysis to benchmark the costs of electricity produced from the proposed configuration against conventional alternatives. The results indicate that the Desert Module outperforms the conventional module across all performance metrics, enhancing the average efficiency by 0.5%. In addition, the performance ratio for the Desert Module stands at 0.87, surpassing the 0.82 achieved by the conventional module. Throughout the experiment, the average energy yield was enhanced by 5.8% and the conversion efficiency by 1.95%. Notably, during the hottest period (between July and August), the deviations on the energy yield and the conversion efficiency exceed 7% and 3%, respectively, in favor of the Desert Module, highlighting its resilience to the high temperatures characterizing desert locations. Furthermore, the Desert Module demonstrates a 4.44% reduction in the levelized cost of electricity compared to the conventional module, positioning it as a more economically viable option for large-scale energy generation in desert environments.

Solar cell UV‐induced degradation or module discolouration: Between the devil and the deep yellow sea

AbstractFor decades, photovoltaic (PV) module yellowing caused by UV exposure has been observed on solar arrays in operation. More than an aesthetic inconvenience, this phenomenon can severely impair module performance and promote other degradation mechanisms by undermining the photoprotection provided by encapsulation. To understand how this reaction may affect current encapsulation materials, silicon heterojunction (SHJ) monocell modules with either UV‐cut or UV‐transparent commercial encapsulants were aged under UV irradiation and examined by visual inspection, fluorescence imaging and flash tests. Despite the photoprotection they provide, only the encapsulants that were stabilised by UV absorbers underwent discolouration. On the one hand, UV absorber photodegradation is responsible for the formation of yellow chromophores that affect light transmission to the cell, which could cause net decrease in the photogenerated current high as 4% after 4200 h of accelerated UV ageing. On the other hand, UV‐induced degradation of SHJ solar cells only accounts for a lower photogenerated current loss (3%), in contrast with previous observations in the literature. According to the behaviour of the current encapsulation formulation, the stability of UV absorbing additives has to be improved to ensure the durability of the device over 30 years.

An advanced method for the development of highly reliable asphalt concrete mixture

This paper introduces the new technology of road construction pavement Superpave. From the beginning of the technology, the method of calculation of road pavement temperature has been taken as an example on the Shymkent city road in Kazakhstan. The material calculation for high quality was conducted with the new climate data of the exact city. A new methodological approach will determine the most accurate selection of bitumen binder grades using a specifically developed PG Grade calculation based on the meteorological data for the period from 2000 to 2020 (20 years) for the specific city. This will be intended to establish requirements for bitumen binders testing by the traditional method for both original and modified bitumen, such as penetration, softening point, and flash and fire point tests, taking into account the climatic characteristics of the republic. Today, have to be accounted that the most common bitumen binder is a 70-100 penetration rating, which means that quite incorrect to use at the highest temperature in Shymkent at +41.3°C and with the lowest temperature at -17.8°C. The results will help to decide on the use of polymer modification of binders, taking into account the design temperatures and operating conditions of asphalt concrete surfaces.

An internally consistent procedure to characterize single carbon number fractions for phase equilibrium of petroleum mixtures: Application to Brazilian pre-salt reservoir fluids

Each natural accumulation of hydrocarbons has unique chemical and molecular characteristics. A complete experimental assessment of every substance involved is impossible and, in most cases, gaps left by laboratory tests must be filled by empirical correlations to provide the minimum set of parameters necessary for the proper functioning of a thermodynamic model. In the present work, a new procedure is developed for calculating the critical properties and acentric factor of single carbon number (SCN) fractions, valid for the C7-C22 interval (Mw≤300g/mol) and successfully tested for mixtures containing heavy fractions with average molecular weights up to 520g/mol. The proposed method is based on a refit of existing correlations that fully respects the internal consistency of the equations. These, in turn, were selected by observing the trends described by the critical compressibility factor in the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) cubic equations of state, resulting from the introduction of a volume translation parameter. After applying the new procedure to characterize ten oil samples collected from High-Pressure High-Temperature (HPHT) reservoirs in the Brazilian pre-salt cluster, thermodynamic parameters derived from flash and differential liberation tests were successfully predicted. With average absolute deviations of 8.38% and 8.32% for the SRK and PR equations of state, respectively, the proposed method is superior (or at least equivalent) to other characterization schemes considered in the study, with the advantage of being thermodynamically consistent.

Condition Assessment of Solar Modules by Flash Test and Electroluminescence Test

The Hungarian society and the Hungarian state are constantly increasing their solar capacity. More and more solar power plants are being put into operation. The largest of these has a 100 MW peak capacity. Such power plants do not require constant maintenance. However, in the case of low productivity, a conditional assessment is required. The reason for production loss can also be manufacturing, installation, and operational errors. A flying drone was used for finding failures by thermographic scouting. Furthermore, electroluminescent (EL) and flash tests give a comprehensive view of the real state of the modules in a mobile laboratory. We had the opportunity to summarize these test results of more than a thousand modules operating in a solar power plant. The report on the power plant shows that a significant part of the modules became unusable in a short time. After four years, 10% of the 260 Wp modules suffered a performance reduction of more than 10%.

Investigating the potential of using dry battery waste powders (DBWPs) as a modifier for asphalt binders

This study aims at investigating the potential of using dry battery waste powders (DBWPs) as modifiers in asphalt binder. A 60/70 penetration grade asphalt binder was used in this study. DBWPs, which were extracted from spent batteries, were mixed with the asphalt binder at seven different percentages [0% (control sample), 2%, 4%, 6%, 8%, 10%, 15%, and 20% by weight of asphalt binder]. The mixing process was performed at 175 °C for 30 min using a high-speed mechanical mixer. To study the effect of DBWPs on asphalt binder properties, both traditional and Superpave binder tests were carried out. Consistency tests included penetration, softening point, and ductility, while Superpave tests included Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR). Flash and fire point tests were also conducted. The test results indicated that the addition of DBWP to the asphalt binder decreased ductility and penetration values and increased the softening and the flash and fire points of the asphalt binder. High-temperature rutting performance of asphalt binder, as presented by DSR rutting parameter (G*/sinδ), was improved by adding DBWP. The high-temperature performance grade of asphalt binder was raised by one grade by adding DBWP up to 10%, two grades at 15%, and three grades at 20%. On the other hand, fatigue and low-temperature performance of asphalt binder were adversely affected by adding DBWP. The Superpave fatigue parameter (G*.sinδ) was negatively increased by increasing the content of DBWP but remained less than the Superpave limit (≤ 5000 kPa). The low-temperature asphalt binder grade was decreased from − 22 °C (for control asphalt binder) to − 16 °C at 15% DBWP and then to − 10 °C at 20% DBWP. Therefore, it is recommended to use DBWP modifier in high-temperature regions to resist rutting distresses.

Experimental Investigation on Production of Jatropha Methyl Ester

At present transportation and agricultural machinery are heavily dependent on petroleum fuels. In current scenario few nations only produce the petroleum fuel that leads to variability in the cost and demand in supply of fuels. Due to this problems it is necessary to find an alternate source for the mineral oil. Based on many research work biogas, ethanol, methanol and vegetable oils are best alternate fuel for mineral oil. The vegetable oils are consider as an alternate to mineral oils since they are environmentally friendly and biodegradable. Compare to mineral oils vegetable oils has high viscosity, low friction coefficient, low volatile, high flash and fire point. In this work it shows that Jatropha oil Methyl Ester (JME) based biofuel is an alternative to fossil fuels. JME can be used as an alternate to fossil fuel and also due to its viscosity index and lubricity properties it has the potential to use as lubricant. The Ester is formed by transesterification process and the viscosity, flash and fire point tests are conducted to analyse the properties of JME over mineral oil. Further, the maximum yield of JME is obtained by varying the proportions of KOH (catalyst), methanol (alcohol) and stirring speed by L27 Orthogonal Array based on Taguchi method.

Assessment of Strength Characteristics of Bituminous Concrete Modified using HDPE

Bituminous Concrete is composite material made by mixing aggregates and bitumen in fixed proportions used for construction of bituminous pavements. Bituminous pavements transfer wheel loads to subgrade by grain to grain transfer mechanism, to transfer loads by this mechanism the bituminous concrete should have high strength. To overcome the problems posed by increased traffic load and deteriorated environmental conditions different types of modifiers are being used in bituminous concrete. Modification of bituminous concrete is done to increase its stability and improve other characteristics. HDPE is one modifier which have been used and being used in bituminous construction. Bituminous concrete modified using HDPE is formed by mixing HDPE in bituminous concrete. In the present study HDPE is used as modifiers for bitumen as well as for bituminous concrete. HDPE were added to bitumen and physical properties of modified bitumen were assessed by conducting penetration value test, ductility value test, softening point, flash & fire point tests on bitumen modified using HDPE. After assessing the physical properties of modified bitumen cylindrical moulds were casted using BC modified by using HDPE, the amount of HDPE was varied from 8% to 10% by the weight of bitumen. Marshall Test was performed on the cylindrical moulds to find stability value and flow value of bituminous concrete modified using HDPE. Results of study revealed that, ductility value and penetration value of bitumen decreased with increment of HDPE content while softening point, Flash & Fire point increased with increment in HDPE content. When HDPE were used in BC and checked for Marshall Stability values, stability increased first reached maximum and then started decreasing. The maximum stability value was obtained for 9% content of HDPE by the weight of bitumen. Economic usage of HDPE in BC was evaluated for 1Km, 7m lane width and 50mm thickness of bituminous concrete pavement. Therefore, use of HDPE in bituminous concrete provides a viable solution for the disposal of waste HDPE, this factor alone makes use of HDPE in bituminous concrete very acceptable and admirable

Influence of Arc Flash Performance and ESDD Measurement of Bushings Tainted by Nitrates

Tainting devastate the feat of bushings. Conductors are insulated inside the bushing that carry a high voltage current through a grounded enclosure. An aspiration is to study the pollution performance of bushings tainted by Nitrates.Arc flash tests of 1kV,11kV,17.5kV bushings are tainted by three types of salts such as NaCl, NaNO3, KNO3. The morsels are negotiated under habitual environment as per IEC 60507. The impact of tainting salts with their solubility on Equivalent Salt Deposit Density (ESDD) and bushings arc flash voltage are scrutinized. The effect of tainted salts on arc flash fruition, the sway of volume conductivity and Equivalent Salt Deposit Density (ESDD) under different percentages are also scrutinized. The research upshot reveals that the Equivalent Salt Deposit Density (ESDD) rate escalated with escalating salt content. When salt concentration gets escalated then conductivity also get escalated. When Equivalent Salt Deposit Density (ESDD) get Escalated then the arc flash voltage and leakage current get slacken. Finally, the graphs are drawn between ESDD and Arc flash voltage, Conductivity and Salt concentration, Arc flash voltage and Leakage current are obtained using MATLAB software.

Investigation of PV yield differences in a desert climate

PV modules which are less sensitive to temperature (i.e. have lower power temperature coefficient, PTC) are expected to produce more energy in hot environments. Yet a year-long study of 26 PV technologies in Doha, Qatar, found that their daily Specific Yield (Wh/day/Wp) only weakly correlated with their PTC. To investigate possible explanations, we examined in detail the field data from one multi-Si and one CdTe string, and calculated their energy losses attributable to module temperature, low-light conditions, and “Wp discrepancy” (difference in Wp between manufacturers’ flash tests and field measurements). We found that although the CdTe system had lower PTC than multi-Si, it had larger Wp discrepancy, which largely accounted for its lower Specific Yield. Further, PTC values derived from field measurements were significantly different from the modules’ nameplate values, for both the multi-Si and CdTe systems. The results indicate that modules’ nameplate PTC values did not strongly predict their relative Specific Yields in desert climates, largely because of discrepancy between nominal and field values of PTC and Wp.

Lumonil Compounds in Criminal Chemistry (A review part I)

Despite the development and progress in the detection of the significance of crimes, and after more than eighty years of discovery is a luminol is the basic chemical in the detection of crimes previously and now, was addressed the theoretical aspects of the compound of the luminol preparation methods and some of its chemical reactions as well as discuss the phenomenon of scintillation and transfer Energy, and then addressing some of the applications of chemical flash and receptor tests, DNA investigations were discussed, and the sensitivity of these reactions.

Analysis of Asymmetrical Component Influence on Arc Current in the Determination of Arc Thermal Performance Value of Protective Personal Equipment

An evaluation of relevance of current asymmetry on arc flash tests intended to determine arc rating parameters on fabrics and garments, as well as face shields, gloves, and other materials were performed. Asymmetrical current is mentioned in American Standards (ASTM F 1959) to be maximum during tests and a reference on International Standard IEC 61482-1-1:2009, item 6.9, where an X / R ratio is required to obtain an asymmetry factor of 2.3, with a recommended source voltage of 2000 V. IEEE 1584 studies on the other hand states all calculation processes not clearly regarding asymmetry of fault current but assuming the linear effect of time and current on energy derived from steady-state current values. Technical basement for the asymmetry factor is never mentioned on arc flash test standards but it is supposed to be related to test strength conditions. As thermal conversion relationship with asymmetry is not clear in the literature, this study investigated, simulated, and performed practical measurements of electrical and thermal parameters related to arc flash tests, concluding that both symmetrical and asymmetrical arcing currents will confer the same arc rating results. Practical tests also showed that a source voltage of 2000 V is necessary only to produce arcing current asymmetry as lower voltages can be used to ignite and keep symmetrical arcing current for sufficient time on the arc rating tests, as previously regarded on literature which reduces significantly test setup and circuitry.

Newspaper reporting of the April 2007 eruption of Piton de la Fournaise, part 2: framing the hazard

An analysis of the front pages of 120 consecutive editions of the local newspaper for the island of La Réunion (France), “Le Journal de L’Ile de La Réunion”, published before, during and after the April 2007 eruption of Piton de la Fournaise reveals that its front page is an ideal vehicle for maximizing information delivery and recall during a volcanic eruption. Supported by flash tests, and by cross-checking with a content analysis of information given within the newspaper, we find that the front page is an effective gauge for the hazard frame which, for the case examined here, involved six volcanic hazards (pit-crater collapse, lava flows, gas, air fall, ocean entry lava flow and bench collapse), as well as the issue of evacuation. We found that crater collapse and lava flow hazards were framed using their natural colors and clear imagery of the phenomenon, tied to context-setting explanations within the newspaper. However, for lava flows in particular there was an element of spectacle and promotion of sightseeing, with photographs always featuring sightseers invariably taking photographs. After the end of the eruption reporting became almost entirely focused on tourists and sightseeing. Gas and ash fall hazard were framed using images and words of the victims, so that it became worrying and frightening, and associated with panic. As a result, the volcano itself became portrayed as a monster, and the situation for the impacted population became “apocalyptic” and “hellish”. This probably contributed to the evacuation measures being described as confused and pointless, with the morale of the impacted population suffering accordingly. The ocean entry and bench collapse had no frame at all, and became associated with the dead, exotic fish that were collected; this hazard thus being framed as an interesting curiosity rather than a volcanic hazard. The front page-tracking model followed here could guide future educative measures during volcanic crises by quickly identifying, on the basis of front page analysis, hazards that are appropriately conveyed versus those that are poorly portrayed. Responses to rectify a poor frame can include reactive scientific advertising, a route that is used commonly by businesses seeking to boost sales by taking timely advantage of a developing newspaper frame, and distribution of appropriately designed and timed press releases.

Rapid and Flash Tests: Indicator for Quality of HT‐PEM Fuel Cells Batches?

AbstractIn order to control the batch quality of membrane electrode assemblies (MEA), two new short tests have been developed. The first being a rapid test, composed of a start‐up and break‐in followed by initial characterization and has a test duration of about 65 h, while the second is a flash test, which is reduced by the break‐in, so that the maximum duration is 8 h. These tests have been compared with classical accelerated stress tests like load cycling at high current densities and start/stop‐cycling. For the investigations presented in this publication, high temperature polymer electrolyte MEAs from two different suppliers were used. The extensive electrochemical characterization clearly shows that the newly introduced fast tests can be used to check the batch qualities. In addition to the electrochemical investigations, the phosphoric acid content of all MEAs has been determined and ex situ micro‐computed tomography analysis has been performed.

Effects of waste PVC addition on the properties of (40-50) grade asphalt

Disposal of plastic waste poses a serious threat nowadays. Effective solutions are required to reduce or eliminate this problem. One of these solutions is to use these materials in asphalt mixtures. PVC (Poly Vinyl Chloride) during melting has adhesive properties which can be used with asphalt to reduce the bitumen mixture costs. Investigation of physical characteristics of asphalt cement (40-50) mixed with PVC is presented in this paper. The main objective is to study the change in bitumen properties after mixing with PVC of percent (2.5, 5, 7.5, 10, 12 and 15) % by weight of bitumen. Penetration, ductility, loss on heating, softening point, flash and fire tests were conducted for each percent. It is concluded that penetration decreases by 62.8% on addition of 15% PVC. Ductility also drops when PVC dosage increases. Softening point increases when PVC dosage increases by 6 % for 15% PVC.

Arc Flash Visible Light Intensity as Viewed From Human Eyes

Human eye can be damaged by the intense light from an arc flash event. Though it is certain that high intensity visible light will be emitted during an arc flash event, there is limited research that provides quantitative light intensity estimation during different arcing incidents as viewed from human eyes. To provide better understanding of the light intensity during arc flash events, this paper proposes an arc flash light intensity estimation model based on approximately 1500 measurement data from arc flash tests using ambient light sensors, which are capable of measuring the light intensity of the arc flash as perceived by the human eyes. The proposed light intensity estimation model can be used to evaluate the potential impact of an arc flash on the human eyes. In addition, the autodarkening welding lens is used in the arc flash testing to explore its effectiveness in attenuating the light intensity and mitigating the exposure to the light hazard during an arc flash event.

DC Arc Model Based on 3-D DC Arc Simulation

DC arc flash hazard assessment is a mounting concern with the recent development of large-scale photovoltaic arrays and dc buses. Currently, there are few methods available to model dc arcs and are largely based on historical arc tests, which may not be suitable for modern dc applications. In order to provide a suitable method to predict dc arc flash properties in power systems, new dc arc model development is necessary. Historically, model development was constrained by time consuming and limited laboratory arc flash tests. This paper proposes a new dc arc model based on 3-D dc arc simulation that is capable of providing comparable results to available lab testing.

Developing and validating test items for first-year computer science courses

We report on the development, validation, and implementation of a collection of test items designed to detect misconceptions related to first-year computer science courses. To this end, we reworked the development scheme proposed by Almstrum et al. (SIGCSE Bulletin 38(4):132–145, 2006) to include students’ artifacts and to simultaneously incorporate think-aloud interviews and flash tests. We also investigated to what extent the practical efficiency of detecting certain misconceptions could be increased without significantly affecting the sensitivity of the instrument, and present positive and negative results regarding this goal. The results of a first transfer and implementation study suggest that it is indeed possible to use the test items in a large-scale practical setting – both as diagnostic instruments and as interventions.

POWER-LAW WRINKLING TURBULENCE-FLAME INTERACTION MODEL FOR ASTROPHYSICAL FLAMES

We extend a model for turbulence-flame interactions (TFI) to consider astrophysical flames with a particular focus on combustion in type Ia supernovae. The inertial range of the turbulent cascade is nearly always under-resolved in simulations of astrophysical flows, requiring the use of a model in order to quantify the effects of subgrid-scale wrinkling of the flame surface. We provide implementation details to extend a well-tested TFI model to low-Prandtl number flames for use in the compressible hydrodynamics code FLASH. A local, instantaneous measure of the turbulent velocity is calibrated for FLASH and verification tests are performed. Particular care is taken to consider the relation between the subgrid rms turbulent velocity and the turbulent flame speed, especially for high-intensity turbulence where the turbulent flame speed is not expected to scale with the turbulent velocity. Finally, we explore the impact of different TFI models in full-star, three-dimensional simulations of type Ia supernovae.

Multi-scale 3D image-based modelling of a carbon/carbon composite

Detailed thermal and mechanical finite element analyses of woven composites are computationally challenging due to the heterogeneous nature and the geometrical complexity of the composite. In this paper two finite element three-dimensional image-based models at different length scales are used to evaluate the thermal diffusivity and stiffness of a 2D carbon/carbon composite. The micro-scale model was developed from SEM micrographs of the carbon tow whereas the macro-scale model was derived from high resolution x-ray tomographic images of the composite. The micro-scale model predicts thermal conductivities and Young's modulus at the tow scale in the three orthogonal directions (x, y and z). The output results from the micro-scale model are then incorporated in the macro-scale model to obtain through-thickness thermal diffusivity and in-plane Young's modulus. The modelling results are in excellent agreement with the experimental results obtained from the laser flash and tensile tests and the deviations are within the bounds of numerical error of 5%.