Heavy Damage Research Articles

Failure analysis and damage causes of a steam turbine blade of 410 martensitic stainless steel after 165,000 h of working

Due to the special working environment of steam turbine blades, such as high temperature and cyclic stresses, they are routinely under heavy damage conditions. Of the most applicable of the alloy used in such blades are martensitic stainless steels which are heat and corrosion resistance and have high strength creep characteristics. In this investigation, a 410 stainless steel type of steam turbine blade, which was damaged after working for about 165,000 h, was studied to define the possible failure mechanisms involved. Optical microscopy and Field Emission Scanning Microscopy (FE-SEM) Analyses, together with hardness measurement, were performed to differentiate the various modes of failure. Results pointed to the presence of fatigue signs on the fracture surfaces. As well, the presence of foreign particles of SiO2 and Fe2O3 could bring about the effect of corrosion and lead to an increase in failure speed. Finally, it was suggested to perform shot peening or apply some protective coatings to increase the service life of these types of turbine blades.

Evaluation of environment carrying capacity as a coastal tourism using GIS in Sepanjang Beach, Indonesia

The rapid pace of population growth in coastal areas and increasing the need for natural tourism can have a negative impact on the quality and quantity of natural resources and the environment in Sepanjang Beach, Gunungkidul regency. The phenomenon of seawater tidal waves led to a number of buildings along the beach experiencing heavy damage. The purpose of this research is to know the environment carrying capacity seen from the aspect of land capability and land suitability aspects as a tourist area, as well as providing recommendations that are right on Sepanjang Beach. The methods used are spatial analysis methods using geographic information systems (GIS) and scoring methods to determine the environment carrying capacity and land suitability. The results of the calculation of the environment carrying capacity based on the aspect of land capability were obtained by 2 classes of land capability namely moderate and good. Whereas seen from the results of the suitability of the beach recreation category shows if Tourism Suitability Index (TSI) has a value of 94% which means it is appropriate. However, it is necessary to arrange the gazebo building to use upland land in the form of alluvial karst plain.

Colocasia Esculenta as a Corrosion Inhibitor in Low Si Containing Al-S Aluminum Alloy in HCL

Corrosion causes heavy damages to all metallic elements. Different machines and structures made of metal experiences this problem. Different fossil lubricant is used to avoid the corrosion in metal. Importance of bio-lubricant is inevitable in order to save the environment as well as for sustainable development. This paper represents the Colocasia esculenta as a corrosion inhibitor in low Si containing Al-S Aluminum alloy in HCl. Four different solutions such as HCl of Ph. value of 0.59; Colocasia esculenta leaf juice of Ph. value of 6.66; 60% HCl,40% Colocasia esculenta leaf juice of Ph. value of 0.79 and 40% HCL, 60% Colocasia esculenta leaf juice of Ph. value of 0.98 are considered. Firstly the weights of the four samples are taken. Then they are kept in four different solutions for 15 and 30 days. Later the weight of each sample is measured and compared with the previous weight. The weight of each sample decreased slightly. Finally, morphological analysis of the samples is performed by SEM to investigate

Forensic investigation in a multiple trauma deceleration case due to road traffic accidents

Background: Road traffic accidents (RTA) are the series of events from road events that are unexpected, and always cause damage to objects, injury and even death. Factors for the occurrence of RTA can be in the form of vehicle, road and human. In this case RTA occurred because of human negligence and road factors. The human factor in the form of the driver driving a vehicle at high speed with an estimated 160 Km/h at night, the other factor is the driver is sleepy or tired. Road factors contribute to the occurrence of accidents due to wide and declining road segments cause the driver unable to control vehicles at high speed, quiet roads and inadequate street lighting conditions. This accident resulted in a heavy damage to the vehicle and all passengers died. The explanation of the causes and patterns of death is important in forensic investigations of RTA victims.Case description: A case of RTA with multiple deceleration injuries was reported. This traffic accident case involved a minibus car speeding and crashing into a bulk cement tank truck that was stopped on the Banda Aceh-Meulaboh National Road, on 30 October 2016 around 04.15 a.m which caused all passengers of minibus died. The speeding minibus car suddenly stopped and hit the back of the tank truck, as a result the body moving at the speed of the vehicle suddenly slowed down (deceleration) causing multiple trauma. The effects on the bodies of the victims varied in the form of open head trauma, closed head trauma, chest trauma, abdomen and extremities. The mechanism and cause of death of the victims was massive bleeding in several organs, especially the head (traumatic brain injury) and chest (rib fracture).Conclusion: Forensic investigations are very useful in determining the cause of death, mechanism of death, manner of death, magnitude of the impact, direction, speed, and nature of the traffic accident.

Defect evolution in Ni and solid-solution alloys of NiFe and NiFeCoCr under ion irradiation at 16 and 300 K

Single-phase concentrated solid-solution alloys (SP-CSAs) have shown unique chemical complexity at the levels of electrons and atoms, and their defect evolution is expected to be different from conventional dilute alloys. Single crystals of Ni, NiFe and NiFeCoCr are chosen as model systems to understand the chemical complexity on defect formation and damage accumulation in SP-CSAs under ion irradiation. The high-quality crystals were irradiated at 16 and 300 K to different ion fluences, to form irradiated region with little to heavy damages. The ion-induced damage was determined using Rutherford backscattering spectrometry technique along a channeling direction (RBS/C) and the level of lattice damage in irradiated Ni and SP-CSAs was quantified from Monte Carlo (MC) simulations. The results are interpreted using the Multi Step Damage Accumulation model to reveal material damage accumulation kinetics. Key findings of the study are that in case of room temperature irradiations the damage level measured for complex alloys at the highest irradiation fluence of 2 × 1015 cm−2 (∼3 dpa) is significantly higher than that obtained for pure nickel samples and suggest two-step damage accumulation process with a defect transformation taking place at a fluence of about 1.5 × 1015 cm−2. Moreover, structural and damage kinetic differences clearly imply that, with increasing degree of chemical complexity and high solid-solution strengthening effects from Ni to NiFe and to NiFeCoCr, the enhanced lattice stiffness resists to randomization of atomic configurations and inhibits the growth of extended defects.

Characterization of Thermally Induced Runaway in Pouch Cells for Propagation

Thermal runaway of lithium-ion batteries is particularly dangerous in systems where runaway can propagate through many cells. To understand thermal runaway propagation in these systems, it is important to understand the differences between failure characteristics of the initial cell that fails due to an abuse event and subsequent cells that fail due to thermal runaway propagation. This work compares thermal runaway events for single cells failed using a heater with cells failed due to propagation in an array. Most of the tests were conducted in an inert environment within a pressure vessel. Cell clamping stress, vessel gas pressure and temperature data show that runaway in cells within an array traverses the cells more slowly and releases gas at a slower rate than singly failed cells. For heater-initiated cell failure, post-experiment cell teardowns suggest that thermal runaway originates at a single point and creates a gas flow stream that causes heavy damage and exits from one side of the cell. Teardowns of cells which failed due to array propagation show more uniform damage and gas release from a larger area.

Application of Time Domain Reflectometry Method in Monitoring State Parameters of Subgrade Soil in Pavement

AbstractMoisture content has a direct influence on structural performance of pavement. Every year in Australia, heavy vehicles damage roads when the moisture content of the pavement layers reaches ...

Overexpression of phzM contributes to much more production of pyocyanin converted from phenazine-1-carboxylic acid in the absence of RpoS in Pseudomonas aeruginosa.

Pyocyanin produced by Pseudomonas aeruginosa is a key virulence factor that often causes heavy damages to airway and lung in patients. Conversion of phenazine-1-carboxylic acid to pyocyanin involves an extrametabolic pathway that contains two enzymes encoded, respectively, by phzM and phzS. In this study, with construction of the rpoS-deficient mutant, we first found that although phenazine production increased, pyocyanin produced in the mutant YTΔrpoS was fourfold much higher than that in the wild-type strain YT. To investigate this issue, we constructed phzM-lacZ fusion on a vector and on the chromosome. By quantifying β-galactosidase activities, we confirmed that expression of the phzM was up-regulated when the rpoS gene was inactivated. However, no changes occurred in the expression of phzS and phzH when the rpoS was knocked out. Taken together, overproduction of the SAM-dependent methyltransferase (PhzM) might contribute to the increased pyocyanin in the absence of RpoS in P. aeruginosa.

Pavement damage behaviour of urban roads in seasonally frozen saline ground regions

Wide-spread frost heave caused by soil freezing and pavement cracking due to frost action, which are the prevailing types that cause heavy damage to road engineering, have been observed during the service periods of urban roads in southern Xinjiang. In this study, several types of pavement damage were measured by long-term observations. Based on observed data and embankment geometry, pavement damage, PCI, salt contents distribution and ground temperature were analysed and discussed. The most common forms of pavement damage were longitudinal cracking (LC), transverse cracking (TC), and waving, which were observed in 45.01%, 20.33%, and 45.38%, respectively. Approximately 20% of the damaged pavement was also affected by TC in addition to LC. The results showed that pavement damage was closely related to the saline soil distribution, freeze-thaw cycles, water migration and embankment geometry. The damages due to frost heave and thaw settlement were more severe with a high salt content than with a low salt content. All the above forms of damage increased with increasing salt content and declining ambient temperature distribution. Furthermore, characteristics of damaged pavement have potential applications in designing road construction analyses and further investigations in seasonally frozen saline ground regions.

Blood heavy metals and DNA damage among children living in an informal E-waste processing area in Vietnam

This study was carried out to compare the concentration of heavy metals in blood and DNA damage among children living in an informal e-waste processing village (exposed village) and a reference village in Northern Vietnam. The results revealed that the blood levels of nickel and arsenic in the children at the exposed village were significantly higher than those at the reference village at p < 0.05; however, no significant differences were observed for lead, cadmium, and chromium in children’s blood between the two villages. The overall levels of five heavy metals in exposed children’s blood were significantly higher than those in non-exposed children at p < 0.001. The DNA damage of the children at the exposed village was significantly greater compared to that of the children at the reference village at p < 0.001. The overall blood metal level of the children at both villages was positively correlated with DNA damage given as Tail Length (Spearman r = 0.249, n = 80, p < 0.05), indicating that a higher level of DNA damage could be induced by higher heavy metal exposure among children. It was found that heavy metal pollution from e-waste processing activities could be a potential risk posing to children’s health.

Estimating the Threshold Value of Disaster-Causing Snowfall by Region and Its Application to Regional Classification

In this study, the estimation of damage-causing thresholds and their application to regional classification were examined using logistic regression, critical success index, probability of detection, and a false-alarm ratio. For 10 stations where damage caused by heavy snow occurred frequently, the fresh snow depth data provided by the Korea Meteorological Administration and heavy snow-related damage data obtained by the Ministry of Interior and Safety were used. Results show that the estimated thresholds differed by region. These results are attributed to many factors such as analysis methods, regional disaster protection, the response of local residents, vulnerability of structures, and meteorological characteristics. Additionally, based on estimated thresholds, the area with the highest threshold-sensitivity and the areas with the most internal differences and similarities between calculated thresholds corresponded to the coastal region, the Gangwon region, and the inland region, respectively. Gangwon region, where heavy snow was often observed, had a long duration of snowfall, whereas inland regions faced snowfalls that were relatively weaker in intensity and shorter in duration.

Shear Wave Velocity Structure Construction Using Ambient Seismic Noise Tomography (ANT) In Palu, Central Sulawesi

Palu is located in Central Sulawesi, Indonesia, characterized by a complex geological setting due to the intersection of Indo-Australia Plate, Philippine Plate, and Eurasia Plate. These plates intersection causes one of the most active fault systems in Indonesia with 42 mm/year relative block motion, the Palu-Koro Fault. Palu-Koro Fault system is a left-lateral fault causing the 7.5 Mw Palu-Donggala Earthquake on 28 September 2018. Moreover, the thickness of the sediment layer in Palu ampli_ed the groud motion. So, it is critical to understand more about the Palu-Koro Fault and its geological system that can be very important for hazard study. In this study, Ambient Seismic Noise Tomography (ANT) was applied to understand the Palu-Koro Fault and its geological system. ANT uses the recorded ambient seismic noise events to obtain experimental Greens function by cross-correlating two seismic record data from two seismic station. Technically, ANT is similar to surface wave tomography which produces two dimensional velocity maps. To produce the two dimensional velocity maps, processing sequence consists of the preparation of single station data, stacking, cross-correlation, Frequency-Time Analysis (FTAN), and surface wave tomography. In this study, the vertical component seismic data was processed from 22 stations in Palu to extract the Rayleigh wave dispersion. The entire data was processed at 0,5 - 5 s period range. In addition, depth inversion step was also applied to get the geological features for the further interpretation. The results of this study are the interstation dispersion curves which indicate the group velocity varies between 0.2 and 2 Km/s, the group velocity maps and the shear wave velocity structure at 0,5 5 Km depth. These results show us the existence of the low-velocity anomaly in the northern part of Palu associated with the coastal sediment, the high-velocity anomaly in the west alongside the N-S direction fault, the low-velocity anomaly in the southern eastern part, and three main geological features in Palu based on the East West cross-section. These results lead to an insight that the heavy damage of the Palu-Donggala Earthquake in 2018 was caused by the thickness of the sediment in Palu.

Living with natural hazards: Tropical storms, lava flows and the resilience of island residents

Our research explores the complexities of experiencing consecutive natural hazards by the residents of Puna, Hawaiʻi, who were significantly impacted by Tropical Storm Iselle and the June 27th lava flow in 2014. The district of Puna suffered heavy damage from Tropical Storm Iselle, a natural hazard of short duration, followed by the June 27th lava flow, a natural hazard of extended duration. Our study used qualitative, open-ended interviews and participant observation to examine the responses of individuals and communities in this low-income, rural area. Themes common to both Tropical Storm Iselle and the June 27th lava flow include the successful dissemination of information by trusted agencies, use of local and indigenous knowledge, and the substantial impact of these occurrences on children.

Computation of Ground Motion Amplification Scenario in NCT Delhi for Earthquake Engineering Purposes and Seismic Microzonation

This paper presents a scenario for the spatial variation of the fundamental frequency of the sediment deposits above the basement and the corresponding amplification as well as the average spectral amplification in different frequency bandwidths for the National Capital Territory Delhi (the capital of India). The exposed central quartzite ridge and the Yamuna River channel are responsible for very large spatial variations of the fundamental frequency in the eastern part of the National Capital Territory Delhi. At 20% of the considered sites, a good match is obtained between the fundamental frequency computed numerically using available S-wave velocities to a certain depth and their extrapolation and that obtained experimentally. The computed fundamental and dominant frequencies reveal that both medium-rise (5–10 storey) and high-rise (> 10 storey) buildings in the western part and medium-rise buildings lying in the localities east of or very near to the Yamuna River may suffer heavy to very heavy damage due to the occurrence of the double resonance phenomenon. Furthermore, 1–2-storey buildings lying on the weathered exposed quartzite rock may also suffer heavy damage during local earthquakes because of the occurrence of double resonance. The possible reasons behind the lack of earthquake damage to the Qutab Minar, the tallest brick masonry minaret in the world, over the last 800 years may be the nonoccurrence of double resonance and almost no amplification in the low frequency range. There are two localities in the western part of the National Capital Territory Delhi, namely Kanganheri-Chhawla and Buradi, wherein all sorts of buildings are highly vulnerable to earthquake damage. For the closed Chhatarpur Basin and a semiclosed basin to its northeast, formed due to exposed quartzite rock, three-dimensional (3D) simulations are required to predict the characteristics of basin-generated surface waves and their focusing effects in the Chhatarpur Basin. The average spectral amplification map developed for the 0–10 Hz bandwidth depicts a range of 2.25–4.82 in the National Capital Territory Delhi and may be directly used to transfer the estimated seismic hazard at basement to the free surface.

Quantitative assessment of secondary metabolites and cancer cell inhibiting activity by high performance liquid chromatography fingerprinting in Dendrobium nobile

Dendrobium nobile is an important medicinal food beneficial for human health, well known for polysaccharides and dendrobine. For fast, accurate, and comprehensive comparison of its quality, high performance liquid chromatography (HPLC) fingerprinting method was constructed. Firstly, spring frost stressed D. nobile herb was observed for assessment. Decreased leaf thickness, chlorophyll, and drying rate, and increased free-proline indicated heavy damages on growth. But, the content of polysaccharides increased significantly in during-frost (DF), and dropped significantly in after-frost (AF). The content of dendrobine accumulated significantly in AF. Then, low similarity among HPLC fingerprints of before-frost (BF), DF, and AF, and 75.82% of significantly variant peaks indicated the changing of much more components. Especially, some less-polar components increased significantly in DF, but not in AF. Moreover, the highest suppression rates (SRs) to A549 lung cancer cells were up to 33.08% in DF, but only 15.63% and 12.12% in BF and AF. After association analysis, eleven less-polar components were found to be significantly and positively correlated to SRs under relatively high concentration. The result shows that frost stress not only causes damages to plant growth, but also promotes the accumulation of some health-beneficial bioactive metabolites. HPLC based fingerprinting method shows good applicability on quality evaluation and bioactivity correlation analysis of complexed agricultural products.

Reverse engineering directed gene regulatory networks from transcriptomics and proteomics data of biomining bacterial communities with approximate Bayesian computation and steady-state signalling simulations

BackgroundNetwork inference is an important aim of systems biology. It enables the transformation of OMICs datasets into biological knowledge. It consists of reverse engineering gene regulatory networks from OMICs data, such as RNAseq or mass spectrometry-based proteomics data, through computational methods. This approach allows to identify signalling pathways involved in specific biological functions. The ability to infer causality in gene regulatory networks, in addition to correlation, is crucial for several modelling approaches and allows targeted control in biotechnology applications.MethodsWe performed simulations according to the approximate Bayesian computation method, where the core model consisted of a steady-state simulation algorithm used to study gene regulatory networks in systems for which a limited level of details is available. The simulations outcome was compared to experimentally measured transcriptomics and proteomics data through approximate Bayesian computation.ResultsThe structure of small gene regulatory networks responsible for the regulation of biological functions involved in biomining were inferred from multi OMICs data of mixed bacterial cultures. Several causal inter- and intraspecies interactions were inferred between genes coding for proteins involved in the biomining process, such as heavy metal transport, DNA damage, replication and repair, and membrane biogenesis. The method also provided indications for the role of several uncharacterized proteins by the inferred connection in their network context.ConclusionsThe combination of fast algorithms with high-performance computing allowed the simulation of a multitude of gene regulatory networks and their comparison to experimentally measured OMICs data through approximate Bayesian computation, enabling the probabilistic inference of causality in gene regulatory networks of a multispecies bacterial system involved in biomining without need of single-cell or multiple perturbation experiments. This information can be used to influence biological functions and control specific processes in biotechnology applications.

Damage study and seismic vulnerability assessment of existing masonry buildings in Northeast India

The Northeast region of India is considered to be the most seismically active zone in India, having witnessed two major earthquakes (Mw > 8) in the past. Recently, the 2017 Ambasa earthquake (with Mw of 5.7) caused significant damage to unreinforced masonry (URM) buildings in Tripura, a Northeast state of India. The typical nature of damage observed in URM buildings during the post-earthquake damage survey highlights poor construction practices that have been used in this region even though the seismic hazard of the Northeast region of India is well established. In this context, the present study is an effort to evaluate through fragility analysis the vulnerability of existing low-rise URM buildings in Agartala, the capital city of Tripura, which in a broader sense represents the buildings of the entire Northeast region of India, through fragility analysis. In this regard, an assessment method based on a nonlinear static approach is used to develop bilinear capacity curve parameters. The capacity curve parameters are then used to estimate fragility functions. Fragility analysis shows that URM buildings would suffer heavy damage even for an earthquake having Peak Ground Acceleration (PGA) of 0.18 g, which is used to design buildings in the Northeast region of India according to the Indian seismic code. Fragility curves developed in this study may prove useful for assessing the seismic risk of the same building typology in other urban areas of Northeast India. In this first attempt, however, the effect of variability from construction quality and modelling uncertainty on the fragility curves is not considered in the limited scope of the present study.

Seed-borne infestation and management of Alternaria Species in mustard seed at Chitwan district, Nepal

Alternaria blight in mustard cause heavy damage to the foliar parts resulting into poor growth and development of plants and thereby reduces seed yield. Inorder to manage Alternaria infestation in mustard seed for yield maximization, an experiment was conducted in the plant protection laboratory in Nepal Polytechnic Institute, Bharatpur, Chitwan in 2018, using Completely Randomized Design (CRD) with four replicates. Five treatments i.e.Uthane M-45 (2g/kg), Neem powder (3 g/kg), Bojho powder (4g/kg), Trichoderma harzianum, (107 Conidia/mL) and control (without treatment) were used for seed treatment of local variety of Mustard. Four hundred seeds for each treatment (25 seeds in each petriplate) were plated using triple layers of moistened blotter paper in petriplate and incubated at (27±20C) for 2 days and followed deep freezing for 24 hrs. Data of disease incidence and seed germination were recorded in 3, 7 and 10 days after incubation (DAI). Seedling vigor and seedling weight were also recorded at 5 DAI. The percentage of Alternaria spp incidence on seeds at different DAI showed highly significant with respect to different treatments. Application of Uthane M-45 and T. harzianum significantly reduced the seed-borne infection of Alternaria spp. as compared to control. At 3 DAI Uthane M-45 completely checked the pathogen however, only 4% and 5% disease incidence was observed in 7 DAI and 10 DAI respectively. Bio control agent Trichoderma harzianum was found next best alternative after Uthane M-45 to control disease. Plant extract Bojho powder and Neem powder were found better than control to check the disease. Furthermore, highest germination (76%) was observed in Trichoderma treatment whereas, lowest germination was found in control.

Geotechnical Site Investigation and Evaluation of 20 March 2019 Mw 5.5 Acıpayam (Denizli) Earthquake

An earthquake with a magnitude of (Mw) 5.5 occurred in Yenikoy village of Acipayam district (Denizli) on 20 Mart 2019 caused heavy damages on masonary structures in Acipayam basin. Groundwater level from ground surface in the basin varies between 1m and 11m, and soil structure of the basin is made up of silty, gravely and sandy clay. Soil liquefaction was not observed in the basin after the earthquake. The main reasons of the heavy damage on the structures are mainly, high value of soil amplification, use of clayey adobe bricks and hollow bricks for building masonary houses, unpermitted construction of roof floors by using hollow bricks.

A new form of steel base isolation system for seismic high-rise building

The higher story of a building then it will be more vulnerable to its earthquake or seismic responses. The use of seismic devices will reduce earthquake force. In this study, the steel base isolation material has been proposed. This paper aims to design a new steel base isolation system that have good resistance in both of seismic vibration and axial pull out. The building data are 3D mini three-story, six-story, nine-story steel frame structures. The shaking table is used to test with two types of vibration, medium and maximum. FEM analysis was implemented to find the seismic responses. From the calculation results, a reduced response was obtained in conditions of moderate damage to a three-story frame with an average acceleration of 88% reduction, a maximum acceleration of 22% reduction and a six-story frame in heavy damage with an average acceleration of 73%, the maximum acceleration is reduced into 43%.