Bend Area Research Articles

Intensification of Hurricane Idalia by a river plume in the eastern Gulf of Mexico

Abstract Hurricane Idalia formed on 26 August 2023 and three days later rapidly intensified from a Category 1 to Category 4 strength storm in less than 24 h over the west Florida shelf. On August 30, it made landfall along Florida’s Big Bend area as a Category 3 hurricane. Strikingly, despite Idalia’s moderate intensity and favorable vortex structure, neither upper ocean thermal energy nor environmental vertical wind shear conditions were as favorable during its intensification from Category 2 to Category 4 as earlier in its path, raising the question of what external factors contributed to its extreme intensification during this phase. Using satellite data, underwater glider observations, and numerical model outputs, this study reveals that, in addition to the 2023 marine heatwave, an extensive riverine plume in the eastern Gulf of Mexico, extending from the Mississippi-Alabama-Florida shelf to the Straits of Florida, produced a ∼20 m thick low-salinity layer (∼34–34.5 psu) and a corresponding warm upper ocean (>29 °C, ∼25–30 m thick). This defined a 10–20 m thick strongly stratified barrier layer below the surface layer with buoyancy frequencies exceeding 10−3 s−1 that suppresses vertical mixing and became a critical factor contributing to Idalia’s rapid intensification under the relatively less than favorable thermal and wind field environments. Therefore, incorporating the river plume in future forecast models appears to be essential to improve the accuracy of intensity predictions, especially in the areas affected by the plume, where stratification plays an important role in the intensification dynamics.

Analysis and Comparison of the Projectile Impact Response of an Electron Beam Melt-Ti64 Body Centered Cubic Lattice-Cored Sandwich Plate

Abstract Background One potential application of additively fabricated lattice structures is in the blade containment rings of gas turbine engines. The blade containment rings are expected to be able to absorb the kinetic energy of a released blade (broken blade) in order to protect the engine parts from damaging. Metallic lattice-cored sandwich plates provide a gap (free space) between two face sheets, which helps to arrest the released blade and increases the energy absorption capability of containment rings. Objective The objective was to investigate numerically the projectile impact response of Body-Centered-Cubic (BCC) Electron-Beam-Melt (EBM) lattice-cored/Ti64 face sheet sandwich plates as compared with that of an equal-mass monolithic EBM-Ti64 plate. Methods The projectile impact simulations were implemented in LS-DYNA using the previously determined flow stress and damage models and a spherical steel impactor at the velocities ranging from 150 to 500 m s−1. The experimental projectile impact tests on the monolithic plate were performed at two different impact velocities and the results were used to confirm the validity of the used flow stress and damage models for the monolithic plate models. Results Lower impact stresses were found numerically in the sandwich plate as compared with the monolithic plate at the same impact velocity. The bending and multi-cracking of the struts over a wide area in the sandwich plate increased the energy absorption and resulted in the arrest of the projectile at relatively high velocities. While monolithic plate exhibited a local bent area, resulting in the development of high tensile stresses and the projectile perforations at lower velocities. Conclusions The numerical impact stresses in the sandwich plate were distributed over a wider area around the projectile, leading to the fracture and bending of many individual struts which significantly increased the resistance to the perforation. Hence, the investigated lattice cell topology and cell, strut, and face sheet sizes and the lattice-cored sandwich plate was shown potentially more successful in stopping the projectiles than the equal-mass monolithic plates.

ANALISIS RISIKO K3 DENGAN METODE HIRARC PADA PROSES BENDING SEMI FINISH PLATE BUMPER HM400 KOMATSU DI PT. KHARISMA LOGAM UTAMA BEKASI

The increasing competition in the industrial sector has driven companies to enhance productivity while maintaining the safety standards. PT. Kharisma Logam Utama (KLU), a manufacturing company specializing in metal and machinery components, is a key partner for PT. Komatsu Indonesia, producing parts for heavy equipment such as the KOMATSU HM400 articulated dump truck. The bending process of semi-finished plates, an essential step in bumper production, poses significant risks to worker safety. This study aims to analyze occupational health and safety (OHS) risks using the Hazard Identification, Risk Assessment, and Risk Control (HIRARC) method. Data collection was conducted through direct observation and interviews over August to September 2024. The findings highlight that most risks in the bending area are categorized as Level II (acceptable with monitoring), constituting 45% of identified activities. Level I risks, deemed acceptable, made up 35%, while Level III (problematic, requiring immediate action) constituted 15%. The highest risk level, IV (unacceptable), accounted for 5% and demands urgent corrective measures due to potential serious injuries or fatalities. The analysis identified mechanical hazards such as cuts, pinches, and material falls as prevalent. Implemented controls included personal protective equipment (PPE) like anti-impact gloves, safety boots, and safety goggles, alongside procedural guidelines. The application of the HIRARC method proved effective in prioritizing risk mitigation measures and improving workplace safety, ultimately contributing to a safer production environment.

Numerical and Experimental Analysis of Roller Hemming on Door Panel’s Curved and Straight-Edge of Flat Plane

Owing to its enhanced production efficiency, roller hemming has become the mainstream process for forming and joining metal sheets in the automotive industry. This study investigates the roller hemming process of a specific car door panel through a combination of experimental analysis and finite element analysis (FEA) on both straight-edge and curved-edge flat surfaces. Consequently, the mechanical properties of the door panel, including tensile strength, yield strength, modulus of elasticity, and Poisson’s ratio, were estimated through tensile testing and then underwent finite element modeling. The simulation results demonstrated the varying distribution of stress during the rolling hemming process, with the highest stress concentration observed in the bending area. Additionally, creepage and growing results were acquired from both simulation and experimental data to validate the precision of the numerical model. A comparison was made between the experimental and simulation results of the external forces exerted by the roller on the panel. In both straight- and curved-edge sections, the external force during final hemming exceeded that during pre-hemming, as revealed by experimental measurements of both normal and tangential external forces, surpassing their corresponding simulated values.

Research on the relationship between comprehensive characteristics of cracks and stiffness of RC beams

The relationship between crack comprehensive characteristics and the stiffness of RC beams is investigated through experimental tests and numerical simulations. A synthetic parameter, the surface damage ratio (SDR), is proposed to represent the comprehensive characteristics of cracks, including crack width, length and location. Crack propagation in RC beams is simulated using a dual-damage parameter plastic damage model. A method for calculating the width and length of cracks is developed based on integral point strains and element equivalent length. The accuracy of this method is verified by comparing it with the results of four-point bending tests on RC T-beams and rectangular beams. Correlation analysis indicates that the cracks in different zones have varying impacts on beam stiffness, with crack length in the bending area and crack width in the shear area having a greater impact than others. To consider the comprehensive characteristics of cracks and their impact on beam stiffness, the SDR, the ratio between the entire crack area and the intact area of the beam surface, is proposed. The proposed parameter is shown to increase linearly with load, resulting in beam stiffness degradation following a power law. The accuracy and applicability of the proposed SDR and its correlation with load and stiffness are verified through load tests on rectangular beams with different reinforcement ratios using Cervenka’s test. Parameter analysis has shown that the section modulus, concrete strength, reinforcement arrangement, and ratios significantly influence how beam stiffness varies with SDR. The presented simulation model for concrete crack evolution, combined with the synthetic parameter of crack characteristics, and the correlation analysis, provide a valuable approach for the safety evaluation of concrete beams during their service life.

Experience of preputiotomy performing in bull with acroposthitis and fibrous affect of penis’ S-shaped curve

The aim of this study was to perform a preputiotomy with the formation of an artificial opening in a breeding bull to realize his reproductive potential. Scientific and production research was conducted in the spring of 2024. In a 3.5-year-old Holstein breeding bull, kept at a breeding station for keeping breeding bulls, acroposthitis and fibrous lesion of the penis in the area of the S-shaped bend were detected due to the developed infectious process caused by Pseudomonas aeruginosa. The resulting pathology prevented the penis from fully extending beyond the preputial sac when collecting sperm for an artificial vagina (the last sperm collection was performed on 02/07/2024). The operation performed consisted of the following stages: insertion of a thick-walled tube into the preputial sac for better orientation in the tissues; making a V-shaped incision of all layers of the prepuce near its fornix; excision of the prepuce section necessary for free removal of the penis when collecting sperm; formation of an artificial opening by connecting the parietal preputial layer to the skin with an interrupted suture. The postoperative period included daily monitoring of the animal's condition, antibiotic therapy (amoxicillin (0.15 g), three injections every 48 hours), and the use of non-steroidal anti-inflammatory drugs (meloxicam (0.002 g), 3 days). A month after the operation, sperm was collected (06.05.2024, three months later) and the presence of all unconditioned reflexes was noted. At the same time, the copulatory reflex was full, painless and ended in ejaculation. The obtained volume of sperm after two mountings was 2.5 ml, the concentration was 1.3x108, the activity was 8 points. Thus, preputiotomy is an effective method for surgical correction of lesions of the preputial sac and adhesions in the area of the S-shaped bend of the penis in breeding bulls.

Microstructure evolution and springback behavior in single-pass roll bending of magnesium alloy plates

Using magnesium alloy plates instead of high-strength steel and titanium alloys in roll-formed parts significantly improves the lightweight, damping, and heat dissipation properties of automotive components. This paper employs finite element simulation combined with experimental methods to perform single-pass roll bending of AZ31B magnesium alloy plates at angles of 0°-15°, 0°-25°, and 0°-35°. Measured the springback angle and microhardness at the bends, and used optical microscopy (OM) and electron back scatter diffraction (EBSD) to analyze the microstructural characteristics, texture, and orientation evolution at the bend during the roll bending process. The results indicate that during roll bending, the inner bend area has significantly more twins than the outer area, with more pronounced grain refinement on the inner side. {10−12} tensile twins mainly coordinate plastic deformation, with some {10−12}-{10−12} tensile twin variants present. The inner bend area's texture shifts from ND to TD direction, strengthening the TD direction texture, while the outer area retains typical rolling texture. The prismatic slip in the inner region of the bend changes from hard to soft orientation. The inner region is mainly coordinated plastic deformation by prismatic slip, while the outer region is mainly coordinated by basal slip. As single-pass roll bending angles increase, the increase in twin boundaries and low-angle grain boundaries (LAGBs) significantly reduces the springback angle. Additionally, grain refinement and increased geometric necessary dislocation density lead to higher microhardness.

Investigating structural property of human hair by using infrared free electron lasers

Intense infrared (IR) rays can heat matters and evaporate waters thermally. One of the possible applications will be hair dryer, although the irradiation effects of IR rays on the hair have not been fully explored. In this study, we first examined the interaction of IR rays at various wavelengths from 3.0 µm (near IR) to 90 µm (far IR) with the surface structure of human hair by using IR free electron lasers (FELs). IR-FEL is an accelerator-based pico-second pulse laser, and the feature is the wavelength-tunability with the high-photon density. When one thread of hair was irradiated by the FEL of 6–7 mJ energy at 60 µm, the cleavage occurred, and the morphological destruction was observed on scanning-electron microscopy images after the irradiations at 70 µm and 6.1 µm (amide I). Synchrotron-radiation infrared microspectroscopy showed that those FEL irradiations decreased a shoulder band at 1710 cm−1 that corresponds to carboxyl group in melanin or fatty acids and increased absorption intensity at 500–600 cm−1. On the contrary, the FEL at 90 µm little changed either the surface morphology or the infrared absorption spectra. Interestingly, near-IR FELs at 3.0–3.5 µm induced bending of a hair, and 2D mapping of protein secondary conformations revealed that β-sheet was more increased than the other conformations on the surface of the bending area even at low pulse energy (1–3 mJ). As a result, the structural damage of the hair was least at 90 µm, which implies an ideal wavelength for drying hair mildly.

Numerical Simulation of River Channel Change in the Suspended Sediment-Dominated Downstream Reach of the Sangu River

This study aims to clarify the characteristics of the riverbed deformation, bank erosion, and channel changes in the lower Sangu River basin using a depth-averaged 2-D flow model where suspended sediment transport is dominant and its flow characteristics are influenced by active tides. A 45 km long area including the river mouth is computed using the 2-D model, and the results are compared with the observed channel changes. The computation results show that bed deformation and channel change are mainly caused during the ebb tide period of the spring tide particularly in an area of about 10 km from the river mouth. The detail study domain calculation results show that the flow concentration at the bend area causes the bed erosion there, and the eddy separated from the main stream causes the sediment deposition at the inner bank, while this eddy is not developed at the outer bank, resulting in the bank erosion there. Through these investigations, the characteristics and mechanisms of the morphodynamics in the lower Sangu River reach, particularly the potential of the combination of tides and floods to enhance riverbed deformations and the associated bank shifts, have been clarified.

48‐2: Research on Mechanical Simulation of Flexible AMOLED Module Bottom Frame

With the development of science and technology and consumers' pursuit of high screen ratio, the frame of terminal flagship products has become an important research direction. However, the thinner the bottom frame is, the higher probability of metal wire breakage in bending area. In this paper, we use finite element analysis to simulate the whole bending process of bottom frame, study the influence of bending path, indenter displacement, bending radius and buffer zone on metal wire, summarize the failure mechanism, which provides theoretical basis for fault analysis, stacking structure design and smaller radius design.

Geological study of an outburst flood event in the upper Yangtze River and risk of similar extreme events

Outburst flood sediments are studied on the upper course of the Yangtze River (known as the Jinsha River) where is a key region for the development of hydroelectric power. As the history and magnitude of outburst flooding in this stretch of the Jinsha River during historic times has remained largely undocumented, we have endeavored as part of this study to conduct field investigations into, and provide numerical dating (using OSL and 14C dating techniques) of outburst flood evidence found in the First Bend area of the Yangtze River. Carbonized nutshells and charcoal from the ancient settlement yielded 14C ages that precisely pinpointed an outburst flood event ∼1200–1300 cal yr BP, during China's Tang Dynasty (618–907 CE). However, OSL ages using the minimum age model for all outburst flood samples ranged from 9.1 to 1.8 ka, which was ∼0.5–7.8 ka older than the 14C-dated outburst flood. This discrepancy suggests a potential overestimation of quartz age when dating outburst flood sediments from the Holocene period. Furthermore, using 2D hydraulic modeling, we estimated the magnitude of the aforementioned outburst flood, revealing a reconstructed peak flow discharge of 51,000–55,300 m3/s. This discharge was three times greater than the 10,000-year flood for the hydroelectric power station nearest to the study area. Our study underscores the significant role of combining archaeological and geological evidence in enhancing paleoflood hydrology research. Through a multidisciplinary approach, our findings emphasize the importance of paleoflood hydrology studies in comprehending both the latent and catastrophic flood risks in alpine mountain areas amid the context of global warming. Key points•A series of outburst flood sediments was identified in the First Bend area of the Yangtze River, with a maximum flood water surface ∼86 m high above modern river level.•The obtained 14C ages would suggest that the outburst flood occurred at ∼1200–1300 cal yr BP in the Tang Dynasty (618–907 CE) of China.•The reconstructed peak flow discharge (51,000–55,300 m3/s) is larger than the three times of the 10,000-yr flood for the nearest hydropower station to the study site.

Buckling mechanism and modified direct strength method of CFS built-up beams with multi-box cross section

A comprehensive study on the buckling mechanism of the Cold-Formed Steel (CFS) box beam composed of C- and U-shaped channels is conducted in order to improve the accuracy of the Direct Strength Method for calculating the bending capacity of CFS beams. Experimental tests involving four-point bending are carried out on six CFS box beams with varying screw spacing and stiffener numbers. In addition, numerical analyses are performed by finite element method. Based on the investigation of experiments and parameter analysis, an elastic constraint model for web buckling is proposed and the buckling coefficient are derived by the application of a generalized variational principle. The experiments reveal an interaction between local buckling in the upper flange under compression and the web. When the upper flange in compression buckles before the web, it leads to a reduction in the lateral constraint stiffness of the flange on the web, consequently, resulting in web buckling. An elastic constraint model for web buckling is proposed, incorporating the constraint effects of the upper flange's elastic support on the web. The critical buckling stress and buckling coefficient of the model are derived using the generalized variational principle. According to the experimental and numerical analysis results, the relative restraint stiffness of the flange on the web shows effects on the buckling coefficient. As the screw spacing and the length of the pure bending area decrease, as well as the number of stiffeners increases, the relative restraint stiffness increases. Subsequently, this leads to an increase in the buckling load and ultimate displacement of the CFS beam. Considering the interaction between the buckling of flange and web, the Direct Strength Method in AISI-2016 is modified for the CFS built-up box beam composed of C- and U-shaped channels. The applicability and correctness of the proposed modified Direct Strength Method is approved through the application of multi-box CFS beams composed of 2C-2 U and 3C–2 U channels. Compared with the Effective Width Method in current Chinese code and Direct Strength Method in AISI-2016, the proposed modified DSM exhibits the highest accuracy in predicting the bending capacity of the CFS box beam. It is shown that the proposed method can be effectively employed to calculate the flexural capacity of CFS beams with multi-box under local buckling control.

Comparison of the biomechanical behavior between commercial and 3D-printed patient-specific Ti6Al4V L-Shaped titanium plates following le fort i osteotomy using finite element analysis: A technical Note

ObjectiveTo evaluate and compare the biomechanical behavior of three-dimensionally (3D) printed patient-specific Ti6Al4V with commercially made titanium mini plates following Lefort-I osteotomy using finite element analysis. MethodsLe Fort I osteotomy was virtually simulated with a 5 mm maxillary advancement and mediolateral rotation in the coronal plane, resulting in a 3 mm gap on the left side's posterior. Two fixation methods were modeled using software to compare 3D-printed Ti6Al4V and commercial titanium mini plates, both featuring a 4-hole l-shape with thicknesses of 0.5 mm and 0.7 mm at the strategic piriform rim and zygomaticomaxillary buttress locations. Using ANSYS R19.2, finite element models were developed to assess the fixation plates and maxilla's stress, strain, and displacement responses under occlusal forces of 125, 250, and 500 N/mm². ResultsThis comparative analysis revealed slight variation in stress, strain, and displacement between the two models under varying loading conditions. Stress analysis indicated maximum stress concentrations at the vertical change in the left posterior area between maxillary segments, with the Ti6Al4V model exhibiting slightly higher stress values (187 MPa, 375 MPa, and 750 MPa) compared to the commercial titanium model (175 MPa, 351 MPa, and 702 MPa). Strain analysis showed that the commercial titanium model recorded higher strain values at the bending area of the l-shaped miniplate. Moreover, displacement analysis revealed a maximum of 3 mm in the left posterior maxilla, with the Ti6Al4V model demonstrating slightly lower displacement values under equivalent forces. ConclusionThe maximum stress, strain, and segment displacement of both fixation models were predominantly concentrated in the area of the gap between the maxillary segments. Notably, both fixation models exhibited remarkably close values, which can be attributed to the similar design of the fixation plates.

The study of input power of an underwater free-damping ribbed plate in statistical energy analysis

To study the vibration characteristics of the free-damping ribbed plate with fluid load under point force excitation in statistical energy analysis (SEA), the theoretical model of input power calculation was established in this research. The simulational results from SEA commercial software validated the correctness of the proposed theoretical model. As inferred from the theoretical model, the added damping layer and ribs significantly affect the effective bending stiffness and area density, and the added fluid load only affects the effective area density. These effective parameters will affect the input power of the fluid-loaded free-damping ribbed plate, resulting in increased input power as a function frequency. The research in this paper could provide theoretical guidance on the vibroacoustic analysis of underwater complex ship structures.

Research On the Path of High Quality Development Enabled by Big Data Technology in the Curved Area of The Yellow River

Big data is a key factor of production to promote the current social development, and the good use of big data technology is a must to achieve high-quality development. Jiziwan of the Yellow River is a strategic overlapping area of the western development and the overland Silk Road, which has very important strategic value both in terms of geographical space and historical development. Therefore, it is particularly important to enable the high-quality development of the Yellow River Jiziwan region with big data technology. By analyzing the relevant data of the high-quality development of the main provinces of the Yellow River Bend in recent years, this paper makes a comparison of the gross product of the region in recent years, the added value of the three major industries, and the R&D investment of the industrial enterprises, so as to get the results of the high-quality development of the Yellow River Bend area and the existing problems. Through these analysis results, this paper puts forward some solutions: using big data technology to optimize regional industrial structure, promote high-quality ecological development and promote innovative development. These optimization paths help promote the importance of the digital economy and promote high-quality, sustainable and coordinated development in the region.

THE EFFECT OF PRIMARY LOCALIZATION OF COLORECTAL CANCER
 ON KRAS STATUS AND ITS PROGNOSTIC VALUE

Relevance: Colorectal cancer (CRC), arising from the right-sided or left-sided colon, is a separate clinical and pathological unit. The status
 of KRAS and its predictive value in CRC remain controversial.
 The study aimed to explore the effect of primary tumor localization on KRAS gene status in CRC.
 Methods: The study included 60 patients with colon and rectal cancer. The KRAS mutation test was performed on paraffin-coated tumor samples
 using PCR methods. Colon cancer was divided into right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC).
 Results: KRAS mutation was found much more often in rectal cancer (RC) and sigmoid colon (SC) (p=0.413) than in tumors in other parts
 of the colon. A combined analysis of our data and previously published data showed that KRAS mutation was more common in PSTC, especially
 in the area of the hepatic bend of the colon than in LSTC (p=0.120). The association of the KRAS mutation with the patient’s age (p<0.012) and
 the duration of hospitalization (p<0.001) was established.
 Conclusion: Our study revealed no significant difference in the KRAS status between colon cancer and rectal cancer. However, KRAS
 mutation was much more common in RSCC compared to LSCC. Patients with RSCC with mutated KRAS also had a worse prognosis and
 required longer hospitalization compared to wild-type KRAS. However, patients with LSCC did not demonstrate a similar effect.

Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology

Abstract The occurrence of a sharp turn along the upper course of the Yangtze River is referred to as the “Great Bend” and represents a large-scale drainage reorganization in response to the surface rise of the Tibetan Plateau. However, the timing and mechanism of the formation of the Great Bend remain disputed. In this paper, we report new (U–Th)/He and apatite fission track thermochronological data from the deep river valley in the Great Bend area of the southeastern margin of the Tibetan Plateau. Compared with the adjacent Jianchuan Basin, two phases of younger rapid cooling for the Great Bend area are identified based on thermal-history modeling, namely, Miocene (ca. 17 to 11–8 Ma) and Quaternary, with the former phase being contemporaneous with the formation of the anticline in the Tiger Leaping Gorge. Progressive increases in the normalized channel steepness (ksn) and the degree of river-valley incision with increasing distance downstream for tributaries of the Yangtze River in the Tiger Leaping Gorge indicate that river rerouting and formation of the Great Bend occurred during the Miocene. Samples located at the bottom of the Tiger Leaping Gorge also reveal a phase of rapid cooling since ca. 1.9 Ma, with an exhumation rate of 1.5 ± 0.2 mm/year. We hypothesize that enhanced Quaternary exhumation in the southeastern margin of the Tibetan Plateau occurred mainly within the narrow region between the Sichuan Basin and the Eastern Himalayan Syntaxis, corresponding to an episode of widespread extensional deformation superimposed above middle- to upper-crustal flexure in this region.

Progressive damage analysis of double-layer variable thickness 3D woven composite scaled engine casing

Due to the excellent mechanical properties and strong design flexibility, the 3D woven composite engine casing shows great potential in high performance fields. This article adopted the method of double-layer weaving and adding yarn to achieve the variable thickness of the 3D woven composite engine casing. The purpose of this article is to study the compression performance and failure mechanism of this variable thickness casing in different thickness zones through experiments and numerical simulations to lay a foundation for future optimization and inclusiveness research on this casing with complex thickness changes. Three types of representative volume cells are established for progressive damage analysis. 3D-Hashin criteria and von-Mises stress criterion are used as damage criteria for yarns and matrix. The progressive damage process and the proportion of damage in the inner and outer layers of three types of 3D woven tubes under axial compression load are analyzed. Results show that the main failure modes of the three types of tubes are yarn-matrix compressive cracking along direction 3 and matrix failure. The damages are mostly concentrated in the warp bending area. The proportions of warp yarn damage in the inner and outer layers of three tubes are different.

BEARING CAPACITY, DEFORMABILITY AND CRACK RESISTANCE OF A DAMAGED BEAM REINFORCED WITH FIBER CONCRETE IN THE COMPRESSED ZONE

The paper presents the results of the study of the load-bearing capacity, deformability and crack resistance of a damaged beam reinforced with fiber concrete in the compressed zone. A beam with 40% damage is considered. The research was conducted in two stages. At the first stage, tests of prisms and cubes made of concrete and fiber concrete were carried out, which showed that the introduction of steel fiber into the composition of concrete in the amount of 2% by volume increases the compressive strength by 15.3%. The initial modulus of elasticity of fiber concrete of the specified mixture is 38.0% higher than that of ordinary concrete of this composition. According to the results of experimental studies of prisms, a diagram of concrete deformation, the nature of changes in relative linear deformations of fiber concrete, as well as graphs showing a comparison of the nature of deformation of concrete and fiber concrete were constructed. At the second stage, the beam sample was tested on a specially designed stand. Before concreting, a foam insert was installed in the zone of planned damage, the shape and dimensions of which corresponded to the planned damage. After the concrete set to 70% strength, the liner was removed, and the formed cavity was filled with a 2% fiber concrete mixture. A beam with 40% cross-sectional damage in the mid-compression zone and a near-rectangular damage shape was found to have a load-bearing capacity of 92.0 kN, or 93.9% of the load-bearing capacity of an undamaged beam. Cracking started at the 4th loading stage, when the load value was 26.0kN, i.e. 28.3% of the bearing capacity of the damaged beam. At the same time, 5 cracks formed in the area of pure bending. At the fifth stage, two more cracks appeared. At the 8th and 9th loading stages, 4 more cracks formed. A total of 12 cracks were formed. The maximum final crack opening width was 0.6 mm. Thus, the strengthening of a beam with 40% damage in the compressed zone by the method considered in the work allows you to achieve its bearing capacity, which is 93.9% of the bearing capacity of an intact beam.

New Gastropods from the Gulf of Mexico (Northwestern Florida, the Yucatan Peninsula, and the Flower Garden Reefs of Texas)

Three new species of gastropods are described from the Gulf of Mexico. These include: Fasciolaria ixchel n.sp. (Fasciolariidae) from near Isla Mujeres on the eastern side of the Yucatan Peninsula of Mexico; Jaspidiconus forticostatus n.sp. (Conidae) from the Big Bend area of northwestern Florida; and Jaspidiconus hortusensis n.sp. (Conidae) from the West Flower Garden Reef southeast of Galveston, Texas. The eastern Yucatan fasciolariid is the newest member of a previously-overlooked complex that contains four closely-related Fasciolaria s.s. species that are endemic to the Gulf of Mexico. The two new cones are members of a complex containing ten species of Jaspidiconus that are now known to be inhabit shallow water areas around the Gulf of Mexico.