Low Levels Of Damage Research Articles

МОДЕЛЮВАННЯ ТА ПЕРСПЕКТИВНІ НАПРЯМИ КОНСТРУКТИВНО-ТЕХНОЛОГІЧНИХ СХЕМ ГРУДКОРУЙНУЮЧИХ РОБОЧИХ ОРГАНІВ КОРЕНЕБУЛЬБОЗБИРАЛЬНИХ МАШИН

Для успішного виходу України на західні ринки необхідно забезпечити конкурентоспроможність власної продукції, яка досягається завдяки комплексній механізації технологічних процесів, зниженню витрат праці, збільшенню врожайності та якості одержуваної продукції. Відповідно, метою дослідження було проведення порівняльного аналізу технологій і машин для збирання картоплі, розроблення моделі вдосконалення грудкоруйнуючих робочих органів й окреслення перспективних напрямів удосконалення коренебульбозбиральних машин. Дослідження проводилися шляхом технологічно-конструкційного аналізу технологій і машин для збирання картоплі. У процесі досліджень використовувались методи порівняння та математичного моделювання конструктивно-технологічних схем грудкоруйнуючих робочих органів. Інформаційною базою досліджень слугували праці українських і зарубіжних науковців із технологій і машин для збирання картоплі. На основі проведеного порівняльного аналізу технологій і машин для збирання картоплі виявлено основні конструктивно-технологічні схеми, що впливають на агротехнічні показники збиральної техніки, розроблено модель грудкоруйнуючих робочих органів (збиральних машин). Дана модель включає руйнування ґрунтових грудок: по-перше, катками безпосередньо перед підкопом бульбоносного пласта; по-друге, грудкоподрібнюючими пристроями (балонами, бітерами або інтенсификаторами сепарації) різних конструкцій у процесі виконання технологічних операцій картоплезбиральної машиною. Попереднє руйнування бульбоносного пласта проводиться безпосередньо перед його підкопуванням і в момент підкопування опорними катками різних типів та інших конструктивних і кінематичних параметрів робочих органів машин.

X-ray diffraction line profile analysis of defects in neutron-irradiated austenitic stainless steels at low displacement damage levels

Neutron irradiation-induced microstructural changes in variants of austenitic stainless steels were characterized using the Angle Dispersive X-Ray Diffraction (ADXRD) technique with a synchrotron X-ray source of energy 14.968 keV (wavelength ∼0.82833 Å). SS 304 L(N), SS 316 L(N), and SS 316 materials were neutron-irradiated to low displacement damage levels (1–6.75 dpa) in the Fast Breeder Test Reactor at Kalpakkam at temperatures in the range ∼380 °C-400 °C. The effect of the irradiation-induced defects on X-ray diffraction peak profile parameters such as peak broadening, peak shift, and asymmetry were quantified and related to dislocation density. Peak broadening is found to increase as a function of dpa in most of the cases. Considering the highest dpa sample, lattice contraction has been shown by SS 304 L(N) and SS 316 whereas lattice expansion is exhibited by SS 316 L(N). Asymmetry in peak broadening is found to decrease in case of the highest dpa sample. Ferrite volume percent is seen to have increased as a function of dpa in SS 304 L(N) and SS 316 L(N) but not observed in SS 316. SS 304 L(N) has shown a greater propensity towards the austenite to ferrite transformation and 5 dpa sample has about 18 vol% of α-ferrite. However, in case of 5 dpa SS 316 L(N), ferrite content has increased to ∼4 vol% . The increase in yield strength was also related to the dislocation density amongst all three grades of stainless steel. SS 304 L(N) showed saturation in dislocation density and yield strength around 2 dpa whereas SS 316 L(N) showed linear behaviour up to the highest dpa.

Damage localization using electromechanical impedance technique based on inverse implementation

Structural Health Monitoring (SHM) systems allow maintenance planning which reduces maintenance costs. These systems may also allow lifetime extension of structures which allows reduction in lifecycle costs of structures. As a result, SHM systems have been of interest to researchers in civil and mechanical engineering sectors. The SHM system should be ideally low cost, suitable for continuous monitoring, and able to detect small levels of damage. The sensitivity to small levels of damage is even more important for composite structures as composites have low damage tolerance. Electromechanical Impedance (EMI)-based techniques have been proposed due to their sensitivity to low levels of damage. Furthermore, due to their high frequency of operation they are immune to ambient noise. Most of the studies using the EMI technique were limited to damage detection only. Recently some studies have used a network of sensors for EMI measurements and used them for damage localization. This paper follows on this trend of using a network of sensors for damage localization using EMI technique. A novel inverse algorithm is proposed for the damage localization. For the inverse technique, an analytical model for the correlation of distance and angle with the damage index (DI) is developed. This model is then used to generate a database of the DIs for a large number of damage scenarios. The measured DIs from the structure are then compared with this database and the scenario with the least mean error in the DIs is the predicted damage scenario. The algorithm takes into consideration the modeling errors and the measurement errors through regularization and in turn allows more accurate damage localization. The method is applied on different damage scenarios on an unidirectional composite sample. Some sensitivity studies such as the performance of the method using different fits have been carried out. In addition, the accuracy of damage localization of the proposed technique has been compared to a localization technique found in literature. The results show that indeed the proposed algorithm works and improves the damage localization using the EMI technique.

Taphonomy of bivalve skeletal remains as a means of detecting changes in oxygen depletion and recognizing ancient upwelling environments

Abstract Bivalve shells from shelf and slope environments of the Benguela upwelling system were examined for their state of preservation for the first time, and were used to test whether their preservation is a proxy for spatially variable seafloor taphonomic conditions that lead to different degrees of time averaging. Distinctive shell damage-profiles show increasing shell damage further from the centre of the upwelling cells affected by anoxic conditions (opal and organic-rich) and towards the carbonate- and phosphate-rich facies (with slower sedimentation rates at the margins of the cells. Discrete taphofacies range from a very low damage profile (opal and organic-rich, facies 1) to very high damage (phosphate, facies 3), with elevated numbers of rounded, fragmented and bored shells as well as very little associated sedimentary matrix. This gradient in taphofacies is associated with a gradient from census assemblages with low damage to (within-habitat time-averaged) assemblages in carbonate and (environmentally-condensed) phosphate facies of moderate and higher species richness that are associated with increasing time averaging. This pattern follows the upwelling facies gradient of high opal and organic matter in areas of most intense upwelling cells and outward to aerated but food-abundant carbonate-rich seafloors and spatially coexisting phosphorite-rich concentrations. Thus, the taphonomic gradient ranges from stressful, oxygen-depleted seafloor environment under upwelling regimes that limit metazoan predators and borers (and thus minimize destruction), to well-oxygenated seafloors with increased predators and micro-boring animals that all foster post-mortem shell destruction. The rarity of encrusters is a conspicuous feature of these facies across the whole gradient that may reflect temporary recurrence of oxygen-depleting conditions even at the carbonatic and phosphatic facies. The state of preservation of these shells can serve as a modern analogue for identifying similar settings in the geological record but also for Anthropocene settings affected by eutrophication and expanding oxygen minimum zones. Molluscan taphofacies with unusually low levels of skeletal damage from borers and encrusters can thus represent sensitive proxies of conditions affected by Anthropocene deoxygenation and eutrophication.

Construction of novel cellulase with high activity, great stability and excellent lignin-resistant for efficient enzymatic hydrolysis by hydrophilic and negatively charged modification

The lignin-derived inhibition on cellulase is the most critical bottleneck that must be addressed when converting lignocellulosic biomass through the sugar-platform process. Herein, a novel modified cellulase with high activity, great stability and excellent lignin-resistant ability was synthesized by chemical modification using hydrophilic and negatively charged polyethylene glycol (PEG) derivatives including HO-PEG-COOH and HOOC-PEG-COOH. Both modifications obviously increased the cellulase activity, with 37% (HO-PEG-COOH modification) and 53% (HOOC-PEG-COOH modification) increase, respectively. In addition, the stabilities of both modified cellulases were significantly enhanced, seeing from their much higher activities at all selected temperatures and pH values. The modification resulted in a movement of tryptophan residues to the exterior of enzyme, allowing the substrate chains to be more easily recruited and thus initiating the hydrolysis. The compactness of secondary structure for enzyme was improved, especially, the α-helix content was increased which requires strong hydrogen bonding to generate it, thus enhancing the stability. High hydrophilicity, negative charge and compactness of enzyme conferred modified cellulase good ability to resist lignin adsorption and destruction, thus improving the enzymatic hydrolysis of corn stover. • Cellulase activity is significantly improved by up to 52% after chemical modification. • The migration of Trp residues allows the hydrolysis to be more easily initiated. • High compactness gives modified cellulase great stability and low level of damage by lignin. • High hydrophilicity and negative charge of modified cellulase prevent lignin adsorption. • The novel modified cellulase exhibits promising potential in converting corn stover.

Assessment of the effects of non-structural components on the seismic reliability of structures via a block diagram method

Under a specific ground motion excitation, even if structural components all satisfy a target performance level, the serviceability of the structure might get affected by the performance of non-structural components. Although the overall performance of a structure is affected by the performance of both structural and non-structural components, seismic reliability and fragility analyses usually only focus on the structural elements and their load-carrying capacity. The present study aims to assess the influence of the acceleration-sensitive non-structural components on the seismic reliability of the entire structure. The distinguishing feature of the proposed approach is the adoption of reliability block diagrams for the analysis of each structure, allowing for different combinations of damage for structural and non-structural components. Results are shown for 5-, 10- and 15-story buildings, to demonstrate the significant effects of non-structural components on their overall seismic reliability. Such effects prove to be more evident for the lower damage levels, and the higher seismic intensities. It is shown that non-structural components can lead to a reduction of the overall seismic reliability ranging from 22% to 100%, for situations related to the life safety and collapse prevention performance levels, under the effects of the design basis and maximum considered earthquakes, respectively.

A comparison between the Felix™ electrophoretic system of sperm isolation and conventional density gradient centrifugation: a multicentre analysis

PurposeDeveloping optimized techniques for the isolation of human spermatozoa possessing low levels of DNA damage is an important objective for the ART industry. The purpose of this study was to compare a novel electrophoretic system (Felix™) of sperm isolation with a conventional method involving density gradient centrifugation (DGC).MethodsFive international ART Centres in Australia, India, Sweden, the USA, and China have collaborated in order to compare the quality of the sperm populations isolated by Felix™ and DGC in terms of processing time, sperm concentration, motility, vitality, and DNA integrity as assessed by 3 methods: SCSA, Halo, and TUNEL.ResultsAcross all centers, 112 comparisons were performed. Although significant differences were noted between centers in terms of the quality of the semen samples subjected for analysis, overall, both methods were equally capable of isolating populations of spermatozoa exhibiting high levels of vitality and progressive motility. The absolute numbers of spermatozoa recovered were significantly (p < 0.001) lower with the Felix™ device although sperm quality was higher with 4/5 centers reporting a significant improvement in DNA integrity relative to DGC (p < 0.01–p < 0.001). In practical terms, the Felix™ device featured a standardized 6 min preparation time whereas clinical DGC protocols varied from center to center but generally took around 40 min to complete.ConclusionsThe Felix™ device is a positive technical development capable of isolating suspensions of highly motile spermatozoa exhibiting low levels of DNA damage in a fraction of the time taken by conventional procedures such as DGC.

Neutrophil degranulation, NETosis and platelet degranulation pathway genes are co-induced in whole blood up to six months before tuberculosis diagnosis.

Mycobacterium tuberculosis (M.tb) causes tuberculosis (TB) and remains one of the leading causes of mortality due to an infectious pathogen. Host immune responses have been implicated in driving the progression from infection to severe lung disease. We analyzed longitudinal RNA sequencing (RNAseq) data from the whole blood of 74 TB progressors whose samples were grouped into four six-month intervals preceding diagnosis (the GC6-74 study). We additionally analyzed RNAseq data from an independent cohort of 90 TB patients with positron emission tomography-computed tomography (PET-CT) scan results which were used to categorize them into groups with high and low levels of lung damage (the Catalysis TB Biomarker study). These groups were compared to non-TB controls to obtain a complete whole blood transcriptional profile for individuals spanning from early stages of M.tb infection to TB diagnosis. The results revealed a steady increase in the number of genes that were differentially expressed in progressors at time points closer to diagnosis with 278 genes at 13-18 months, 742 at 7-12 months and 5,131 detected 1-6 months before diagnosis and 9,205 detected in TB patients. A total of 2,144 differentially expressed genes were detected when comparing TB patients with high and low levels of lung damage. There was a large overlap in the genes upregulated in progressors 1-6 months before diagnosis (86%) with those in TB patients. A comprehensive pathway analysis revealed a potent activation of neutrophil and platelet mediated defenses including neutrophil and platelet degranulation, and NET formation at both time points. These pathways were also enriched in TB patients with high levels of lung damage compared to those with low. These findings suggest that neutrophils and platelets play a critical role in TB pathogenesis, and provide details of the timing of specific effector mechanisms that may contribute to TB lung pathology.

Behavior and Damage Characterization of Impulsively Loaded Cross-Laminated Timber Panels

This research bridges the gap between the quasi-static and high-strain-rate loading regimes in cross-laminated timber (CLT) by investigating two areas that have remained unstudied or elusive, i.e., rolling shear failure of CLT under impulsive, blast-like loading and intermediate strain rates in CLT. To study the conditions that would promote shear modes of failure, a novel, highly adaptable center-point testing system and methodology were developed that permitted the application of impulsive loading to undamaged CLT panels in a highly controlled and repeatable manner. The loading condition and low span-to-depth ratio (6.40 ≤ L:h ≤ 6.55) CLT were selected to encourage the development of shear modes of failure. Changes to the rotational rigidity at the boundary conditions allowed for the empirical simulation of realistic boundary conditions. Digital Image Correlation (DIC) and load cell data were used to identify failure modes following loss in resistance in the specimens. Overall, the experiment was successful in consistently eliciting shear modes of failure and providing damage characterization in impulsively loaded CLT. Shear modes of failure resulted in the dramatic loss of resistance in all specimens tested. Strain-rate enhancement in the dynamic apparent flexural stiffness of CLT of 1.3 to 7.2 times was observed. Lower levels of damage were observed in specimens with higher levels of boundary-condition rotational rigidity.

Structural performance of reinforced concrete beams with 3D printed cement-based sensor embedded and self-sensing cementitious composites

Cementitious composites containing conductive functional fillers can achieve self-sensing and continuous monitoring of the damages and cracks through piezoresistive characteristics defined as the electrical resistivity change under external deformation. Previous studies developed two types of self-sensing cementitious composites expressing superior piezoresistive characteristics, as well as good linearity, repeatability, and sensitivity. This research further investigates the flexural damage sensing capability of the developed self-sensing cementitious composites by applying them to reinforced concrete beams. The 3D printed self-sensing cementitious composites containing carbon fibre (CF) at 0.7 wt% and activated carbon powder (ACP) at 0.25 wt% were tested as the embedded sensors in this study. Mould cast self-sensing cementitious composites developed by 100 wt% of magnetite aggregate (MA), 0.3 wt% of CF, and 0.05 wt% of carbon nanotube (CNT) were examined in bulk form. The corresponding fractional change in resistivity (FCR) was attained on the tension face of the reinforced concrete beams when subjected to flexural loading. Experimental findings suggest that the embedded 3D printed cement-based sensors in beam elements can contribute to the load-carrying capacity of the reinforced concrete beam, achieving an average load of yielding at 88.65 kN and a maximum loading capacity of 111.09 kN, which is 10% and 12% higher compared with the controlled reinforced concrete beam, respectively. In terms of sensing performance, both 3D printed self-sensing cementitious composites in sensor form and mould cast self-sensing cementitious composites in bulk form could reflect stress and strain changes and detect crack formation in reinforced concrete beams, which demonstrate gage factors at 318 and 527, respectively. However, 3D printed cementitious sensors are more effective when reinforced concrete beams are severely damaged. In terms of self-sensing cementitious composites in bulk form, the randomly distributed CF and CNT could provide a more pronounced crack and damage sensing capability, with fluctuations that can be observed at both low and high levels of damage.

Where to measure water quality ? Application to nitrogen pollution in a catchment in France

Information on the water quality of rivers can be used to judge the effectiveness of past policies or to guide future environmental policies. Consequently, the location of water quality monitoring stations (WQMSs) plays an important role in river pollution control. In the 2000s, a literature developed on the optimization of WQMS location to identify pollution hot spots, average quality, or to minimize the detection time of a potential source of accidental pollution. This article is part of a new literature aimed at locating WQMSs in order to optimize the economic value of information (EVOI) generated by water quality monitoring networks (WQMNs). The field of study is a catchment in northeastern France where the purpose of quality measurement is to define a policy of reduction of agricultural nitrogen fertilizers in order to reach the standard of 50 mg/l of nitrate at the WQMS. Agro-hydrological and economic models estimate the net benefit of input reduction depending on the location of the WQMS on the basis of different assumptions concerning the ecological damage generated by nitrate. We show that the magnitude of the ecological damage and, consequently, the perception of the contamination generated by nitrate in water, play a decisive role on the optimal location of the WQMS, as well as on the benefit of the economic optimization of locations, compared to traditional optimization. Locating WQMSs in a way that maximizes EVOI will be more attractive for very high or very low levels of damage. However, in this context, linking damage to nitrate concentration or to concentration coupled with riparian population density alone will have little impact.

Deployment Of Pests Grayak Caterpillars (Spodoptera frugiperda) (Lepidoptera: Noctuidae) And The Level Of Damage To Maize (Zea mays) Plantations In Several Locations On Ambon Island

Spodoptera frugiperda is an invasive insect pest that introduced to Indonesia in 2019. This study aims to determine the spread of S. frugiperda pests, as well as the level of damage (plant damage intensity) on corn plantations owned by farmers in several locations in Ambon Island. The research was conducted in six locations, namely Tawiri Village, Taeno Hamlet, Poka Village, Karang-Karang Hamlet, Passo Village and Liang Village. This study used a survey method by direct observation of corn plantations owned by farmers and interviews with farmers. Observations were made when the corn plants were about one month after planting. The results showed that there were S. frugiperda attacks at the six research sites with the highest level of damage was in Taeno hamlet with a damage intensity of 40.94% (moderate category) and an attack area of 90%; while the lowest level of damage was in Karang-Karang Hamlet with an intensity of damage of 7.42% (light category) and an attack area of 30%.

Identification of clinical and rehabilitation groups among patients with cervical tetraplegia

BACKGROUND:Spinal cord injury at the cervical level often leads to a severe neurological deficit, such as tetraplegia (International Standards for Neurological Classification of Spinal Cord Injury) and gross functional disorders. Currently, methods of differentiated rehabilitation strategy are developed, taking into account the needs of the patients.&#x0D; AIMS:This study aimed to examine the clinical heterogeneity of patients with a cervical injury and to form appropriate clinical and rehabilitation groups based on common relevant rehabilitation goals.&#x0D; MATERIALS AND METHODS:We examined 190 patients with severe cervical myelopathy C4D1level aged 1860 years in whom changes in clinical and functional status were monitored for 57 years. The rehabilitation program was standardized and based on existing national clinical guidelines for physical rehabilitation in patients with spinal cord injuries.&#x0D; RESULTS:The greatest changes were in patients with motor levels C6and C7.Patients with cervical tetraplegia, according to the criterion of functional and motor homogeneity, can be divided into four clinical and rehabilitation groups: patients with a high level of damage to C4C6(functionally dependent), patients with a low level of damage to C7D1(functionally independent), patients with complete motor damage (types A and B), and patients with incomplete motor damage (types C and D).&#x0D; CONCLUSIONS:The allocation of clinical and rehabilitation groups allows the prediction of the results and outcomes of rehabilitation. A timely rehabilitation prognosis can improve the quality of life of patients with cervical tetraplegia and their families and contribute to their timely adaptation to society.

Fragility assessment for new and deteriorated portal framed industrial buildings subjected to tropical cyclone winds

Low-rise portal framed industrial buildings are widely used as warehouses, workshops and storage facilities. Damage surveys following severe tropical cyclones have shown that both structural and non-structural damage can occur to these buildings. While non-structural damage to the building envelope of portal framed industrial buildings are considered by several existing fragility models, almost none exist that include structural failures in the wind fragility assessment. This study develops a fragility assessment method for portal framed industrial buildings that accounts for wind-induced damage to both structural (steel portal frame and end wall frame) and non-structural (metal cladding system and fenestration) building components. Fragility curves are developed for a prototype industrial building located on the cyclone-prone east coast of Australia considering four damage states with increasing damage severity. A Monte Carlo simulation incorporating probabilistic models of the spatio-temporal variable wind pressures, wind-induced demands and component capacities is employed to conduct the fragility assessment for both individual building components and the building system under critical failure modes. It was found that the fragility of structural framing is non-negligible when wind speed exceeds 80% of the design level. Structural framing failure is a major contributor to the most severe damage state and is a necessary inclusion in the fragility assessment for this type of building. A sensitivity analysis also showed that fastener corrosion can significantly increase the fragility of deteriorated buildings near to coastlines, particularly for low levels of damage.

S4.3b Candida glabrata-host interactions

S4.3 Emergent species of the Candida genus, September 22, 2022, 10:30 AM - 12:00 PM Candida glabrata is among the most common pathogenic yeasts of humans. Yet, this fungus is phylogenetically, genetically, and phenotypically very different from other clinically relevant Candida species. This includes an unusual high level of intrinsic resistance to antifungals such as azoles. Furthermore, in contrast to the rather aggressive pathogenicity mechanisms of the dominant Candida species, C. albicans, C. glabrata seems to have evolved strategies that are based on stealth, evasion and persistence, without causing severe host cell damage during infection. For example, C. glabrata is unable to invade epithelial cells in vitro and causes only low levels of damage in standard in vitro infection models. However, the addition of a single common host protein, albumin, strongly enhances the damage potential to vaginal epithelial cells. Similar to other Candida species, the potential of C. glabrata to survive in human blood is low. However, C. glabrata can survive within macrophages for long periods without causing host cell damage and responses. This intracellular stage requires the acquisition of nutrients, such as biotin, facilitated by defined biotin up-take systems. Survival in macrophages is further supported by transient mitochondria dysfunction: C. glabrata is able to switch into a petite phenotype upon interaction with human phagocytes. The petite phenotype significantly differs from non-petite cells in its growth behavior, its interactions with the immune system, and even its resistance to antifungal drugs. Effectively, the interaction with phagocytes can render C. glabrata mostly resistant to commonly used azole drugs, and vice versa (‘cross resistance’), providing a principle mechanism by which intrinsic antifungal resistance may have evolved.SourcesSeider et al. (2011) The facultative intracellular pathogen Candida glabrata subverts macrophage cytokine production and phagolysosome maturation. J Immunol. 187(6):3072-86.Brunke and Hube. (2013) Two unlike cousins: Candida albicans and C. glabrata infection strategies. Cell Microbiol. 15(5):701-8.Kämmer et al. (2020) Survival strategies of pathogenic Candida species in human blood show independent and specific adaptations. mBio 11(5):e02435-20.Sprenger et al. (2020) Fungal biotin homeostasis is essential for immune evasion after macrophage phagocytosis and virulence. Cell Microbiol. 22(7):e13197.Pekmezovic et al. (2021) Candida pathogens induce protective mitochondria-associated type I interferon signalling and a damage-driven response in vaginal epithelial cells. Nat Microbiol. 6(5):643-657.Pekmezovic et al. (2021) Human albumin enhances the pathogenic potential of Candida glabrata on vaginal epithelial cells. PLoS Pathog. 17(10):e1010037.Siscar-Lewin et al. (2021) Transient mitochondria dysfunction confers fungal cross-resistance against phagocytic killing and fluconazole. mBio 12(3):e0112821.

Hardening and ductility loss of RAFM steel CLF-1 irradiated with high-energy heavy ions

Irradiation induced hardening and ductility loss of a Chinese reduced-activation ferritic / martensitic steel CLF-1 is evaluated by utilizing the high-energy heavy ion irradiation and the subsequent miniature specimen test technique. Specimens were irradiated with high energy 14N6+ and 56Fe17+ ions supplied by a cyclotron to generate a quasi uniform atomic displacement damage plateau from surface to a depth about 25 μm. Three successively increasing damage levels (0.05, 0.1 and 0.2 dpa) were approached at a low temperature around 223 K. The small punch test at room temperature showed that the ductility loss can be observed at the lowest damage level and increases with the increasing damage level, similar to the variation trend of yield stress with irradiation dose. The TEM observation revealed that the average size and number density of irradiation-induced defect clusters also increased with displacement damage. Assuming that the hardening is caused by the self-interstitial-type dislocation loops, an estimation by combining the numerical calculation of the number density / mean diameter of dislocation loops with the dispersion barrier hardening model yields a similar dose dependence of the irradiation hardening.

Data Mining Motor Vehicle Testing Based On Vehicle Type Using The K-Means Method Case Study Binjai City Transportation Service

Motor vehicle testing is a series of activities to check the components in the vehicle. Motor vehicle testing is very important, because vehicles operated on the road have the potential to cause accidents. So if periodic inspections are not carried out, it cannot provide technical safety to vehicle users, because it is not known what components are lacking and what components must be repaired. In this study, motor vehicle test data will be calculated using the K-Means. The K-means algorithm is aclusteralgorithm non-hierarchical. Cluster analysis is a tool for grouping data based on variables or features. The purpose of k-means clustering, like other clustering methods, is to obtain clusters of data by maximizing the similarity of characteristics within the cluster and maximizing the differences between clusters.groups K-means clustering algorithm data based on the distance between the data and the centroid cluster Cluster with the number of motorized vehicle data based on the type of vehicle as many as 4 vehicles, namely, freight cars, MPU, buses, and betor. Cluster 1 there are 7 groups with 7 types of vehicles: 2 BUS and 5 betor where there is one type of vehicle (betor) that does not pass the test due to the type of damage at the time of testing motor vehicle. Cluster 1 is the type of vehicle that passes the motor vehicle test the most with the lowest level of damage; Cluster 2 there are 4 groups by type of vehicle: 4 Cars of Freight where 2 of them did not pass the test because of the type of damage during the motor vehicle test; Cluster 3 has 9 groups with the types of vehicles: 2 freight cars, 4 MPUs, and 3 BUS. 3 BUS and 1 MPU did not pass the test due to damage during the motor vehicle test. cluster is the cluster of vehicle types that do not pass the test with the most types of damage.

Functional significance of the leaf-cutting ant Atta cephalotes (Formicidae) in coffee plantations: An enemy or an ally?

Leaf-cutter ants are appreciated as ecosystem engineers. Conversely, under agricultural scenarios, they are considered serious pests. Coffee is one of the crops selectively foraged by this species either under traditional shading or unshaded intensified systems. Despite the economic importance of coffee in Neotropical regions, there are few observational field studies on the impact of leaf-cutter ants on coffee plantation soils and how impact may differ in response to shade management. Three hypotheses were tested in coffee plantations in presence of Atta cephalotes: (1) bioturbation activity by leaf-cutter ants depends on the soil properties, which in turn, are affected by agronomic management of the coffee plantations; (2) a relatively higher concentration of resources (i.e., coffee plants) results in greater leaf-cutter ant activity in unshaded plantations than in shaded plantations; and (3) the effect of ant defoliation on fruit production depends on the level of foliar damage. Ten active ant nests were selected from each management system in ten farm plots. Soil samples were collected from nests and from outside the nests (control), physical, chemical and biological properties were analysed, and leaf-cutter ant herbivory was also assessed. No significant differences in microbial activity, evaluated through respiration, were found between nest and control soils. Nest soils had higher and lower percentages of sand and silt, respectively, than the control soils. Nest soils contained significantly higher amounts of sulphur, regardless of shade management. A. cephalotes translocated mineral soils and improved water infiltration in nest soils. The herbivory index and proportion of damage were greater in unshaded coffee, although fruit production tended to increase, possibly due to a compensatory effect as coffee plants responded to low levels of foliar damage. Therefore, the first hypothesis was only partially supported since bioturbation depended on soil properties, and certain soil properties were affected by coffee management, while the second and third hypotheses were supported by the data, suggesting that leaf-cutter ants differentially affect coffee plantations based on their shade management and on the moment the coffee plants are affected. Our results form the basis for the development of future studies that evaluate production impacts and economic damage in coffee varieties by leaf-cutter ants. Depending on the ecological context of the agroecosystem and management practices used, leaf-cutter ants can have positive or negative impacts for coffee production.

THE PERIODONTAL TISSUE STATE IN CHILDREN OF THE JUVENILE AGE TAKING INTO CONSIDERATION THE GENERAL SOMATIC FACTOR

Dental morbidity in children, despite numerous preventive measures, remains very hightoday. The prevalence and severity of the clinical course of periodontal tissue diseasevary widely in Ukraine and other countries, and depends on age.Today, inflammatory diseases of periodontal tissues are considered as a reaction of theorganism to the imbalance between the microbial agent and the protective systems of theoral cavity under the influence of various exo- and endogenous factors. Microflora oftartar, plaque, dental calculus can actively interact with the tissue elements located underthe sulcus epithelium, thus triggering typical pathological processes.Objective – to determine the prevalence and intensity of periodontal tissue damages inchildren with comorbid diffuse non-toxic goitre (DNG).Materials and Methods. To determine the dynamics of changes in clinical parameterswith age, two age groups – 12 and 15 years, among them there were 180 children withDNG, and 80 somatically healthy children have been examined.Results. Examination of somatically healthy children showed the presence of periodontaltissue pathology in 62,00 % of children under examination at the age of 12 years andin 80,00 % of those at the age of 15 years (Fig.1). CCG dominated in the structure ofperiodontal diseases with detection rates ranging from 83,33 to 95,83 %.Conclusions. Regarding periodontal tissue damages by tartar as one of the leading factorsof inflammatory processes in gums and alveolar bone, the following should be noted:there is a low level of periodontal tissue damage in younger children and in somaticallyhealthy children of both ages. The incidence of hard dental deposits in adolescents withDNG is moderate, and high in case of DNG, grade II.

Dislocation structure of tungsten irradiated by medium to high-mass ions

Single crystalline tungsten was irradiated by the medium-mass ion Si with 7.5 MeV and high mass-ion W with 20.3 MeV up to a calculated peak damage level of 0.04 dpa and 0.5 dpa. The obtained dislocation structure of the damage zone was investigated by transmission electron microscopy and systematically compared with each other. Bright-field kinematical images were taken under four different two-beam diffraction conditions g = −200, 020, −110, 110 close to the [100] zone axis. The observed damage depth and damage peak position is in good agreement with the SRIM calculated damage depth profiles. The dislocation structures were investigated at the region of the damage peak because there the damage levels are comparable. In both irradiations (Si and W), the dislocation structures were similar. At the low damage level of 0.04 dpa dislocation loops and dislocation-loop clusters were found. The size of the dislocation loops in the W-irradiated tungsten sample was up to 20% higher than for the Si-irradiated sample. At the high damage level of 0.5 dpa a dislocation network consisting of dislocation-loop chains and dislocation lines was found for both irradiations. The dislocation line density was about 12% higher for the W-irradiated sample. Through comparison of the damage zone to SRIM damage depth profiles it was found that the transition from dislocation loops and dislocation-loop clusters to an ordered dislocation network takes place at about 0.08–0.1 dpa. Despite the large differences in ion mass and irradiation energy the dislocation structures were very similar.