Stages Of Destruction Research Articles

Research on Evolution Characteristics of Shale Crack Based on Simultaneous Monitoring of Multi-Parameters

Meso-crack evolution mechanism of shale is a key factor affecting the mechanical properties of shale. In order to explore evolution laws of cracks in shale during loading, a meso-crack monitoring system, loading test equipment and an automatic ultrasonic data acquisition system were set up. On this basis, a set of experimental apparatus simultaneous monitoring multi-parameters of shale micro-crack was designed, and destruction experiments of shale samples with different bedding angles were carried out to find out evolution characteristics of cracks. The results show the following: (1) The designed apparatus can monitor ultrasonic, mechanical and video information simultaneously of crack evolution in the entire process of shale destruction under load to provide information for analyzing acoustic and mechanical characteristic responses of crack propagation at key time nodes. (2) With an increase in load, shale will undergo four stages of destruction: crack initiation, propagation, penetration and overall failure. In the course of these stages, acoustic characteristics and mechanical characteristics are in good agreement, which proves the validity of predicting rock mechanical parameters with acoustic data. (3) During the loading process of shale, the main amplitude of acoustic wave is more sensitive than mechanical parameters to the change of rock cracks. Research results have important theoretical reference value for evaluating wall stability of shale gas horizontal well with ultrasonic data.

Determining the Stages of Deformation and Destruction of Composite Materials in a Static Tensile Test by Acoustic Emission.

Composite materials are used in many industries. They are construction materials that are being used more and more often, which makes it necessary to accurately identify the process of their destruction. Recent decades have resulted in an intensive increase in diagnostic tests of structures and mechanical elements. Non-destructive testing (NDT) represents a group of test methods (surface and volumetric) that provide information about the properties of the tested element without changing its structure. The method of acoustic emission (AE) is also being used more frequently. Thanks to the ability to detect and locate signal sources, as well as to perform tests during operation, it is a method that is increasingly used in industry. In this article, the acoustic emission was used to analyze the changes occurring in composite materials. Obtained parameters helped to determine the signals originating from fibre delamination, fibre cracking, etc., as well as the starting point of these changes and the stress values at which these changes occurred. The analysis of acoustic emission signals recorded during the tests helped to determine the values of amplitudes characteristic for the destruction mechanisms of considered composite materials. Signals with an amplitude in the range of 30–41 dB may indicate elastic–plastic deformation of the matrix. Signals with an amplitude in the range of 42–50 dB indicate matrix cracks with the accompanying phenomenon of fibre delamination. Signals with amplitudes greater than 50 dB indicate fibre breakage. Based on the test results, the permissible stress was determined; when exceeded, the mechanisms of damage to the structure of composite materials accumulate. This stress limit for the tested material is 70 MPa. The use of the acoustic emission method in mechanical tests may contribute to a greater knowledge of composite materials used as a construction material, as well as determine the stresses allowable for a given structure.

Морфологические изменения в печени овец при экспериментальном мелофагозе и после коррекции

The article shows that experimental infection of sheep with melaphagosis leads to significant structural disorders in the skin and liver. There is local necrosis in the liver. In this case, hepatocytes lose their cytolemma, and the cytoplasm of the cells merges to form a homogeneous mass. Cell nuclei undergo karyopyknosis, chromatin is strongly compacted and is located in small groups in a uniform mass of destroyed hepatocytes. Next to necrotic hepatocytes are hepatocytes with poorly defined cell boundaries. At the same time, hepatocytes lose their orientation, that is, they do not form liver plates. Some of them still retain a pronounced nucleus, the karyolemma. Sometimes changes in the liver cover a vast area and in such areas hepatocytes are at different stages of destruction. In the interlobular connective tissue of the liver, extensive areas with accumulations of lymphoid tissue are revealed. Blood vessels, especially sinusoidal capillaries, are characterized by plethora and perivascular edema. Blood stasis is accompanied by adhesion of leukocytes to endotheliocytes and gradual migration of leukocytes into the perivascular zone. The use of Mediatrin to combat bloodsuckers leads to the elimination of the cause of destruction in the body, but the drug itself has side effects. In sheep, after Mediatrin, destructive processes in hepatocytes remain in the liver, but less swelling and cellular reaction are visible. In the treatment of Mediatrin + Eracondom, clusters of lymphoid cells are still found in the interlobular connective tissue, their number is small, they are mainly concentrated in the area of the liver triad. When Mediatrin + oxymethyluracil (OMU) is added to sheep feed, large foci of necrosis are not detected in the liver. However, individual hepatocytes do not have a clear boundary. In the vast majority of cases, hepatocytes have a cubic or polygonal shape, the nuclei are located in the central zone, the nucleoli are well defined, the chromatin is homogeneous and evenly distributed. Thus, in all experimental groups of sheep, when treated with Mediatrin + Eracond or OMU, a pronounced positive trend in the histological structures of the liver is determined.

Numerical Simulation Study of Anti-Large Deformation Bolt Structure

In order to study the mechanics of the anti-deformation hemp anchor rod, and numerical simulation was carried out with ANSYS finitengen software, the mechanics characteristics of a single spiral anchor and a hemp anchor rod under different spiral rings were compared and analyzed. The results show that for a single screw anchor, the number of spiral turns has a greater effect on the stretch elongation rate of the anchor test piece, and the more spiral turns, the greater the elongation when the anchor is destroyed, and the structural deformation of the anchor rod force is greater, which is the main reason for the increase of the elongation with the increase of the number of spiral rings. The hemp anchor is affected by the number and spacing of spiral rings, and does not produce yield stage and destruction stage when stretching, which indicates that the hemp anchor has better ability to resist shearing and deformation. In engineering applications, the ability of hemp anchor rod to resist large deformation of surrounding rock can be effectively improved, the effect of roadway support can be ensured, and the research results provide theoretical basis for the application and parameter design of hemp anchor.

RESULTS OF COMPARATIVE STUDIES ON THE DURABILITY OF CUTTING CERAMIC PLATES WHEN TURNING HARDENED STEEL BLANKS

The paper presents the results of a study on the durability of cutting ceramics: a replaceable polyhedral plate developed at NSTU and cutting ceramics WOK-60 when processing hardened steel blanks made of 40X (45HRC) steel. As a result of the tests carried out, it was found that with the use of cutting modes developed at KNAU, the durability of SMP from cutting ceramics created at NSTU is more than 1.7 times higher than the performance of plates based on the WOK-60 material. At the same time, the roughness of the treated surface of the work piece was Ra = 0.35 ? 0.05 microns when using SMP from the developed ceramics Ra = 0.55 ? 0.05 microns when using WOK-60 plates. The stages of destruction of cutting ceramic plates are revealed, taking into account the hierarchy of structural scales.

Effect of water on amine-based deep eutectic solvents (choline chloride + monoethanolamine): Structure and physicochemical properties

Water, can not only regulate the thermodynamic properties of deep eutectic solvent (DES), but also affect its supramolecular structure. Therefore, it is necessary and meaningful to study the effect of water on DES. In this work, amine functionalized DES (choline chloride + monoethanolamine) was successfully prepared, and the densities and viscosities of DES + H2O were measured from 293.15 K to 323.15 K. The effects of DES composition, water content and temperature on the excess molar volume, partial molar volume, apparent molar volume, limiting molar volume, coefficient of thermal expansion, viscosity deviation and activation energy for viscous flow were investigated. The hydration and structural changes of DES were analyzed. Additionally, the Redlich-Kister equation was used to correlate the excess properties of DES + H2O. Finally, a three-stage theory of effect of water on DES, namely the pure DES stage, the destruction stage and the thorough destruction stage, was proposed. Conclusively, it can be seen that an appropriate amount of water is very helpful to improve the properties of DES, otherwise the structural advantages of DES will be lost. It is hoped that this study will lay a foundation for the application of DES.

Оценка зараженности хамсы Engraulis encrasicolus нематодой Hysterothylacium aduncum в Азовском море в летний и осенний периоды 2015-2020 годов

The dynamics of infection of anchovy Engraulis encrasicolus Linnaeus, 1758 with nematode parasite Hysterothylacium aduncum Rudolphi, 1802 in the Sea of Azov during the summer seasons of 2015 and 2017-2020 and autumn seasons of 2017-2020 is analyzed. To specify the scheme of infestation, the division of nematodes into living and degenerating ones was used. The degenerating specimens were attributed to three stages of destruction. The infection rate was estimated by using of the common parasitological indices (prevalence of infection, intensity values, abundance of larvae). Statistical analysis of data obtained in the process of the research was conducted using Spearman’s rank correlation.

Three Stages of Composite Specimen Destruction in Static Failure

Abstract The paper presents the results of standard specimen fracture made of anisotropic carbon fiber plastic with an epoxy matrix. Static stepwise loading of the specimen was carried out on an Instron 8801 testing machine to determine the characteristics of ductile fracture G1C in the first mode in accordance with ASTM D5528. During loading, the parameters of acoustic emission (AE) signals, such as AE impulse amplitudes and their energy were synchronously recorded. At the same time, the magnitude of the opening and the growth of the crack initiated by the artificial cut at the end of the specimen were recorded. According to the analysis of the acoustic emission signals, three zones with different G1C behaviour were identified: initial crack propagation, its stationary growth and accelerated fracture of the specimen. The zonal character of the change in the acoustic emission signals made it possible to determine the energy of the acoustic emission signals as diagnostic evidence for the onset of rapid destruction of the specimen. The amplitude of the AE-signals in the zones, however, remained constant. Online monitoring of changes in the energy of acoustic emission signals will prevent the onset of rapid destruction of an object in places of its deformations. The paper does not aim at defining G1C as usual. It presents the investigation of the fracture stages for a composite material using an acoustic emission method.

The Limitation of Endoscopic Surgery Using the Full Endoscopic Discectomy System for the Treatment of Destructive Stage Pyogenic Spondylodiscitis: A Case Series.

Introduction Conservative therapy, including appropriate antibiotics and bracing, is usually adequate for most patients with pyogenic spondylodiscitis. If conservative treatment fails, surgical intervention is needed. However, major spinal surgery comprising anterior debridement and accompanying bone grafting with or without additional instrumentation is often related to undesired postoperative complications. In recent years, with minimally invasive surgery, the diagnostic and therapeutic value of endoscopic lavage and drainage has been proven. This study reports a case series of patients who required open revision surgery after treatment with endoscopic surgery using the full endoscopic discectomy system (FED), indicating the surgical limitations of endoscopic surgery for pyogenic spondylodiscitis. Methods We retrospectively investigated the medical records of 4 patients who underwent open debridement and anterior reconstruction with posterior instrumentation following endoscopic surgery for their advanced lumbar infectious spondylitis. They had been receiving conservative treatment with antibiotics for 12–15 days. They also had various comorbidities, including kidney disease, heart failure, and diabetes. Numerical rating scale pain response, perioperative imaging studies, and C-reactive protein (CRP) levels were determined, and causative bacteria were identified. Primarily, the bone destruction stage was classified using computed tomography with reference to Griffiths' scheme. Results All patients had severe back pain before surgery with no relief of the pain after FED. Increased pain, including radicular pain after FED, was noted in one case. Causative pathogens from biopsy specimens were identified in 3 (75%) of the 4 cases. In preoperative radiological evaluation, all cases were classified as destructive stage in Griffiths' scheme. The CRP levels of all the patients decreased slightly after endoscopic surgery. Relapse of spinal infection after revision surgery was not noted in any patient during the follow-up period. Conclusion The surgical treatment of destructive-stage spondylitis with FED alone can increase low back pain due to aggressive debridement.

Study of Concrete under Combined Action of Aggressive Environment and Long-Term Loading.

A significant part of reinforced concrete structures is subjected to intensive environmental impact during operation. This can cause local destruction and failure of buildings if obligatory measures are not taken to protect them from corrosion. This is especially true for industrial buildings, where the environment could be contaminated with aggressive products or waste. An important issue is the development of methods for calculating the load-bearing capacity and serviceability of reinforced concrete structures with corrosion damage. The main reason for this is the necessity to determine the durability and reliability of buildings and structures and the estimation of their safe operation time. As corrosion damages of concrete are a critical issue, more detailed experimental studies are needed. This paper presents experimental studies of concrete prisms under the simultaneous action of an aggressive environment and a constant level of compressive force. In total, 32 prisms under different loading conditions and in different aggressive medium were tested. Samples were divided in series, for which different load levels were chosen (, , ). Additionally, control samples in the air and immersed in water were tested. During the experiment, different parameters were monitored and recorded: decrease of cross-sectional size, the temperature and environmental humidity. Results of the study showed that destruction occurred due to the presence of corrosion damages of concrete and a reduction of the cross-sectional area. The stresses in the concrete at the destruction stage were less than the value of the prism strength by 10–12%. It was established that along the contour of the section, there is a partially degraded layer of concrete of 1.5–3.7 mm thickness, with corrosion microcracks and corrosion products. Additionally, experimental and theoretical diagrams of concrete with corrosion damages were obtained and compared. The ultimate deformations of concrete with corrosion damage, which correspond to the prismatic strength of concrete, in comparison with undamaged concrete were lower by 11–18%. Therefore, the concrete strength is decreased during exploitation under loading in an aggressive environment, which needs to be taken into account during calculations.

Antioxidant activity, carbohydrates and protein in sorgum (Sorghum bicolor L. Moench) plants as a development of economic functional food materials during the COVID-19 pandemic

This study aims to determine the content of antioxidants, carbohydrates, and protein in Sorghum (Sorghum bicolor L. Moench) as an economically functional food ingredient during the COVID-19 pandemic. The research stages include the manufacture of sorghum seed extract, Antioxidant level testing using the DPPH test, carbohydrate content testing, and protein content determination using the Kjeldahl method, the Kjeldahl method consists of 3 stages, namely: the destruction stage, the distillation stage, and the titration stage. The results showed that Sorghum had an IC50 value of 88.8970 ppm, carbohydrate content of 71.8 g, and protein content of 9.68%. so that sorghum has the potential to develop functional food during the COVID-19 pandemic.

Distribution of dissipated pseudo-strain energies and temperature effect on fatigue cracking resistance in asphalt mixtures under destructive tensile loading

This paper studies the effect of temperature on the resistance of asphalt mixtures to fatigue cracking by calculating the parameters of the modified Paris’ Law more accurately at multiple temperatures in the basis of separating the DPSE components. Firstly, the repeated direct tensile (RDT) tests with two strain levels were performed on four types of asphalt mixtures to obtain the mechanical properties in the non-destructive and destructive stage under 5 sets of temperatures including 0 °C, 10 °C, 20 °C, 30 °C and 40 °C.The results show that energy ratio to develop fatigue cracking (DPSEF) increases first and then decreases with the temperature increasing, while energy ratio to develop permanent deformation (DPSEP) decreased continuously. If only considering for the relative proportion of the two destructive effects, it was found that the dominant damage mode is fatigue cracking in the 0 °C to 20 °C interval. The dominant damage mode at 40 °C is permanent deformation, and the dominant damage mode at 30 °C depends on material types. This finding helps to understand the development and distribution of fatigue cracking and permanent deformation at different temperatures.Then the DPSEF is further introduced to the modified Paris’ Law to derive the coefficients AJR and nJR. The logarithmic form of AJR and nJR at different temperatures follow the same linear relationship while remaining consistent model fitting coefficients. The damage density follows a good linear relationship with the logarithmic form of the parameter nJR which is independent of temperature. Parameter nJR can reflect the level of cracking resistance performance which is not limited by material type and temperature conditions.

Evaluation of the evolution of the structure of cold recycled mixture subjected to wheel tracking using digital image processing

The meso-structural characteristics of cold recycled mixes using asphalt emulsion (CRME) were investigated by wheel tracking tests and two-dimensional digital image processing technology in this study. The trends of contact points, long-axis states, fractional dimensionality, and the rule of aggregate distribution were analysed. Fitted equations of the CRME rutting depth and mesoscopic parameters were established in different loading periods. The number of aggregate contact points appears to increase as the loading time increasing. The long axis of the aggregate tends to be consistent. The long axis inclination and fractal dimension of the aggregate profile gradually decrease over time. The aggregate area ratio increased gradually and then the mixture became dense. The evolution of CRME could be divided into three stages under wheel tracking test: the stage of initial compaction, relative compaction, and destruction. The support vector machine prediction model of rutting depth and mesoscopic parameters was established by K-fold Cross Validation algorithm (K-CV) optimization. The proposed model showed high accuracy for the movement state of the asphalt mixture, which could provide scientific guide for pavement condition evaluation.

Determiantion of energy characteristics of material destruction in the crushing chamber of the vibration crusher

The crushing equipment is characterized by a significant energy-consuming system during the crushing workflow. The current trend in the development of such processes puts forward requirements for the development of new or improvement of existing energy-saving equipment. The essence of the solution to the problem in this work is determined by using resonant modes, which are inherently the most effective. The practical implementation of the resonance mode has been achieved taking into account the conditions for the interaction of the resonant vibration crusher with the material at the stages of its destruction. The degree of the stress-strain state of the material is taken into account, which was a prerequisite for identifying the potential for the development of a vibration load. Composed equations of motion based on a substantiated discrete-continuous model of a vibration crusher and processing material. An approach is applied to determine the stepwise destruction of the material with the determination of the required degree of energy. This methodological approach made it possible to reveal the nature of the process of material destruction, where energy costs at the stages of crack formation, their development and final destruction are taken into account. It was revealed that the greatest energy consumption during the operation of crushers goes into the kinetic energy of the crushing plates and the potential energy of deformation of the springs. The proposed model is common for any design of a vibration machine and its operating modes. The stable resonance mode has made it possible to significantly reduce the energy consumption for the course of the technological process of material grinding. The results obtained are used to improve the calculation methods for vibratory jaw and cone crushers that implement the corresponding energy-saving stable zones of the working process.

Failure Investigation of Layered LFT SB1plus Package after Ballistic Tests for Level IIA.

The main objective of this study focuses on designing and testing body protection systems using advanced materials based on aramid fibers, for high impact speeds of up to 420 ± 10 m/s. Ballistic applications of aramid fiber-based composites mostly include soft body armors. The investigation of the failure mechanisms identifies issues of protective fabrics, major challenges and technological problems for efficient development of these systems. The authors present an investigation on the failure processes and destructive stages of a ballistic package made of successive layers of LFT SB1plus, a trade name for a multiaxial fabric by Twaron Laminated Fabric Technology (LFT), taking into account the particular test conditions from NIJ Standard-0101.06 Ballistic Resistance of Body Armor. The main parameter of interest was the backface signature (BFS), but also details of projectile arrest and SEM investigation could offer arguments for using this material for individual protection. For the reported tests, the maximum and minimum values for BFS were 12 mm and 24 mm, the mean value being 18.66 mm and the standard deviation being 3.8 mm.

АНГИОПУЛЬМОНОГРАФИЯ С НИТРОГЛИЦЕРИНОВЫМ ТЕСТОМ В ДИАГНОСТИКЕ ОСТРЫХ ИНФЕКЦИОННЫХ ДЕСТРУКЦИЙ ЛЕГКИХ

Objective. To develop a method for additional and differential diagnosis of acute infectious lung destruction (AILD) based on angiopulmonography with the nitroglycerin test. Methods. Angiopulmonography with the nitroglycerin test was used in 10 patients with suppurative diseasesof thelung and pleura for additional and differential diagnosis of AILD The method was used in such situations when chest computed tomography did not allow to determine unambiguously the presence and / or prevalence of necrosis of the lung parenchyma. Results. In 3 patients with the lung abscess, a clear restriction of the decay cavity was registered with the preservation of the main blood flow and weakening of the parenchymal phase of the blood circulation along the periphery of the destructive area. During the nitroglycerin test performance there was no change in the filling of the microvascular bed with contrast along the periphery of the decay cavity, which made it possible to determine the presence of parietal sequesters. According to the results of the study, the lung gangrene was diagnosed in 6 patients. At the same time, two variants of circulatory disorders were noted: the first - with preservation of the blood flow through the main vessels and with the absence of a parenchymal phase in the lesion focus, the second - with the violation of the main blood flow. In the affected area no change in blood flow was observed after the nitroglycerin test performance. Similar results of the study indicated the development of necrosis of the pulmonary parenchyma, which was subsequently confirmed during the operations performed. In the site of inflammatory infiltration of the pulmonary parenchyma with preserved main blood flow, the depletion of the parenchymal phase of blood circulation was determined, but after the nitroglycerin test, a pronounced enrichment of the vascular architecture to the parenchymal phase in the pneumonia affecting part of the lung was noted. Conclusion. It has been established that AILD is characterized by irreversible changes in the vascular bed of the lung parenchyma in the lesion focus. Angiopulmonography with the nitroglycerin test is considered to be an additional highly informative method improving the early and differential diagnosis of AILD in difficult clinical situations. What this paper adds It has been found out that during angiopulmonography the areas of pulmonary necrosis are characterized by the absence of a vascular pattern with or without disturbance of the blood flow through the segmental arteries. At the same time, in contrast to the foci of pneumonia, the nitroglycerin test is not accompanied by an evaluation of the filling of the pulmonary vascular bed in the affected area, i.e. blood supply disorders are irreversible. Thus, based on an assessment of the nature and reversibility of the blood flow disturbances in the affected lung, it is possible to carry out differential diagnosis of the early stages of acute infectious lung destruction (AILD) and pneumonia.

Spatiotemporal evolution of the Jehol Biota: Responses to the North China craton destruction in the Early Cretaceous

The Early Cretaceous Jehol Biota is a terrestrial lagerstätte that contains exceptionally well-preserved fossils indicating the origin and early evolution of Mesozoic life, such as birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. New geochronologic studies have further constrained the ages of the fossil-bearing beds, and recent investigations on Early Cretaceous tectonic settings have provided much new information for understanding the spatiotemporal distribution of the biota and dispersal pattern of its members. Notably, the occurrence of the Jehol Biota coincides with the initial and peak stages of the North China craton destruction in the Early Cretaceous, and thus the biotic evolution is related to the North China craton destruction. However, it remains largely unknown how the tectonic activities impacted the development of the Jehol Biota in northeast China and other contemporaneous biotas in neighboring areas in East and Central Asia. It is proposed that the Early Cretaceous rift basins migrated eastward in the northern margin of the North China craton and the Great Xing'an Range, and the migration is regarded to have resulted from eastward retreat of the subducting paleo-Pacific plate. The diachronous development of the rift basins led to the lateral variations of stratigraphic sequences and depositional environments, which in turn influenced the spatiotemporal evolution of the Jehol Biota. This study represents an effort to explore the linkage between terrestrial biota evolution and regional tectonics and how plate tectonics constrained the evolution of a terrestrial biota through various surface geological processes.

Investigation of the Peculiarities of Deformation and Fracture of Metals Obtained on the Basis of 3D Printing with Registration of an Acoustic Emission Signal

The paper investigates the features of deformation and fracture of steels obtained using the technology of 3D printing by electric arc surfacing based on the registration of the acoustic emission signal. With a decrease in the test temperature of 07Cr25Ni13 steel, a decrease in the work expended in stretching the specimen is observed, both at the stage of elastic deformation and at the stage of strain hardening. It was found that the most informative characteristic parameters of the AE signal include: the pulse count rate N, the total count NΣ, and the AE signal entropy. With a decrease in the test temperature, there is a significant increase in the intensity of the AE signal, the total number of pulses at all stages of deformation and destruction of steel. The obtained regularities of changes in the characteristic parameters of the AE signal can be used as diagnostic features, both in assessing the stage of deformation and destruction of the material, and the structural state of the material. Fractographic studies have shown a significant decrease in the tough component of 08Mn2Si steel with a decrease in the test temperature. The fracture mechanisms of 07Cr25Ni13 steel change insignificantly with decreasing temperature, however, a significant decrease in the ductility of the metal is observed, as evidenced by a decrease in the size of ductile fracture cups.

Biology, Taxonomy, and Management of the Root-Knot Nematode (Meloidogyne incognita) in Sweet Potato

Sweet potato is the seventh-ranked food crop produced after wheat, rice, maize, potato, barley, and cassava in the world. It is the most important root tuber crop in temperate, subtropical, and tropical areas of the world. It is grown for food, income-generating, and jobs for farmers and retailers. The important nutritional substances of sweet potatoes are ß-carotene and anthocyanins. However, the production and its valuable products are limited due to root-knot nematode parasitism. One of the most important destructive species of root-knot nematode to this crop is Meloidogyne incognita. The most destructive stage to sweet potato is at its second juvenile stage (J2). At this stage, it invades the roots and tubers of sweet potato highly in warm sandy soil conditions. It is an obligate plant-parasitic nematode. M. incognita caused significant yield loss to sweet potato in terms of quality, quantity, disturbing the process of photosynthesis and nutrient uptake through the formation of galling, establishing of its feeding sites, or induced galls that contain giant-feeding cells, and cracking of tubers and roots directly. It also reduces the market values of the infected tuber of sweet potato by downgrading the production values. The problem of quality and quantity losses to sweet potato by this pest is one of the major problems nowadays. It caused this problem alone or interaction with other plant-parasitic pathogens or through synergistic of fungi, bacteria, viruses, and others. Therefore, this review paper is focused on the sweet potato M. incognita biology, taxonomy, geographical distribution, and management measures.

Study of Solid Medical Waste Management in Aimere Public Health Center, Ngada Regency

Public Health Center is one of the health service units which produces solid medical waste. The results of preliminary data collection indicate that the management of solid medical waste at Aimere Public Health Center is still problematic. The Public Health Center does not provide a means of transporting waste and does not have an incinerator to manage this waste, so there is still a build for the management of solid medical waste at the final disposal site. The management of the solid medical waste process starts from separation, labeling, transportation, storage to disposal/destruction. This study aimed to determine the management of solid medical waste in Aimere Public Health Center, Ngada Regency. This qualitative research used the descriptive survey method. Data collected from Aimere Public Health Center in January-March 2021. Sampling used a purposive sampling technique. The number of informants in this study was 7 people, whose positions and duties were related to medical waste management at Aimere Public Health Center. The results showed that at the sorting stage, medical and nonmedical waste was separated the collection was carried out in each action room, at the transportation stage there were no special tools available according to standards, at the temporary storage stage did not use standard container covers, and at the final destruction stage did not use incinerators according to standards. Aimere Public Health Center should improve the processing of solid medical waste, by providing special tools for transporting the waste, temporary shelters according to standards, and final waste disposal sites).