Final Width Research Articles

Postoperative surgical margin results of the phyllodes tumors from a tertiary hospital.

Phyllodes tumors in the breast are exceptionally uncommon fibroepithelial tumors. In the literature, they are typically categorized as benign phyllodes tumor, borderline phyllodes tumor, and malignant phyllodes tumor. This study aims to assess and present the clinical and surgical outcomes of patients diagnosed with phyllodes tumor. The outcomes of patients aged 18 years and above diagnosed with phyllodes tumor between 2006 and 2023 were retrospectively reviewed. Patients were grouped as benign phyllodes tumor and borderline/malignant phyllodes tumor and compared by clinical and surgical results. Of all 57 patients with phyllodes tumor, 64.9% (n=37) were benign phyllodes tumor and 35.1% (n=20) were borderline/malignant phyllodes tumor [22.8% (n=13) borderline phyllodes tumor and 12.3% (n=7) malignant phyllodes tumor]. When the patients were divided into two groups as benign phyllodes tumor and borderline/malignant phyllodes tumor and compared, our cumulative (total) recurrence rate was 14.0%, with final surgical margin width between groups [(0<final surgical margin<2 mm vs final surgical margin≥2 mm) (p=0.154)] and recurrence [(8.1% benign phyllodes tumor vs 25.0% borderline/malignant phyllodes tumor) (p=0.080)]; there was no significant difference between our rates. Phyllodes tumors of the breast can be followed up with a narrow negative surgical margin (0 mm<final surgical margin<2 mm). However, after the initial surgery, re-excision is recommended for positive margins, while a wider surgical margin (≥10 mm) is not necessary for excision.

Transverse squeeze flow of thermoplastic composite tape during in-situ consolidation via automated fiber placement

Transverse squeezing of thermoplastic composite tapes during automated fiber placement is a challenge in controlling gaps/overlaps of adjacent bands. A theoretical model may provide insights on direct effect of process parameters on deformation of tape. The developed models in this work evaluate non-Newtonian squeeze flow of molten tape using power-law viscosity under three different no slip, perfect slip, and imperfect slip boundary conditions at interface during in-situ consolidation, aiming to predict the final width of tape with minimal computational costs. The results predicted by models are verified using finite element analysis with close agreement. Subsequently, no slip and perfect slip assumptions underestimated and overestimated the experimental measurements of consolidated widths, respectively. However, the squeeze model with imperfect slip condition may effectively capture the trends in the experimental data. This model includes the effect of intimate contact development on the friction parameter during squeezing, utilizing a new non-Newtonian trapezoidal asperity model.

A new deep learning-based approach for concrete crack identification and damage assessment

Concrete building structures are prone to cracking as they are subjected to environmental temperatures, freeze-thaw cycles, and other operational environmental factors. Failure to detect cracks in the key building structure at the early stage can result in serious accidents and associated economic losses. A new method using the SE-U-Net model based on a conditional generative adversarial network (CGAN) has been developed to identify small cracks in concrete structures in this paper. This proposed method was a pixel-level U-Net model based on a generative network, that was integrated the original convolutional layer with an attention mechanism, and an SE module in the jump connection section was added to improve the identifiability of the model. The discriminative network compared the generated images with real images using the PatchGAN model. Through the adversarial training of generator and discriminator, the performance of generator in crack image segmentation task is improved, and the trained generation network is used to segment cracks. In damage assessments, the crack skeleton was represented by the individual pixel width and recognized using the binary morphological crack skeleton method, in which the final length, area, and average width of the crack could be determined through the geometric correction index. The results showed that compared with other methods, the proposed method could better identify subtle pixel-level cracks, and the identification accuracy is 98.48%. These methods are of great significance for the identification of cracks and the damage assessment of concrete structures in practice.

Fabrication of microneedles using wire electric discharge machining and improving surface quality by electrochemical polishing

Microneedle (MN) arrays have many applications in biomedical engineering to deliver drugs transdermally or extract biomarkers from the interstitial fluid from the human skin. Several methods have been developed to fabricate different sizes and shapes of MN using polymers, ceramics and metals. However, most of these methods require expensive sophisticated machines and clean room facilities. So, it is difficult to fabricate microneedle arrays in large quantities at a reasonable cost. This study reports the fabrication of a high-quality stainless steel master pattern for an MN array using a wire-cut electric discharge machining process followed by electrochemical polishing (ECP). Different densities of a 5 × 5 array of microneedles with pyramidal shapes were fabricated by machining channels onto the workpiece surface in a criss-cross pattern. A systematic experimental study was carried out with reference to the offset between the two consecutive channel faces and the depth of channels. The output parameters are MN height (MNH), MN base (MNBW) and tip width (MNTW). The average needle tip width, base width, and height of microneedles were found to be 55.3 ± 5 µm, 679.8 ± 10 µm, and 914.7 ± 19 µm. Finally, the sharpness of the MN tips and the overall surface finish of the MN array were improved with ECP. The reductions in MNH, MNBW, and MNTW were reported to be −18.3%, −9.7%, and −95.4%, respectively, with a final tip width of 2.55 ± 1.62 µm. The MNs’ tip angle was reported to be 32.52° ± 1.56.

Ridge Expansion in Two Surgical Stages Using the Transitional Implant Technique. Case Series with 8-Year Follow-Up

Extremely wide bony ridges require surgical procedures in order to insert dental implants. When less than 3 mm is present, different procedures are available, with ridge splitting being one of the most commonly used. The main limitation of this procedure is the angulation of the inserted implant. The two-stage split with transitional implants was created to overcome this drawback and achieve greater bone volume in the intervention area. This case series shows patients treated with this novel procedure. Material and Method: We retrospectively analysed patients who had undergone two-stage ridge expansion (using transitional implants) with at least 9 years of follow-up from the loading of the definitive implant, both in the maxilla and mandible. Data collection was performed by two independent examiners (different from those performing the prosthetic or surgical phase). All data were entered into a database which was managed by computer for the subsequent statistical analysis. The implant was the unit of analysis for descriptive statistics in terms of location, implant dimensions, and radiographic measurements. The primary variable was implant survival and as secondary variables mesial and distal bone loss and final bone crest width achieved after transitional implant integration, before replacement, were recorded. Results: Thirteen patients were recruited, and 30 transitional implants were inserted for width expansion in two surgical stages. These transitional implants were subsequently replaced by definitive implants at 5 months in the maxilla and at 3 months in the mandible. The mean initial ridge width of all two-stage split sites was 2.65 mm (+/- 0.63), range 1.32 to 3.70 mm. After placement of the transitional implants and bone healing, the final mean width of the specimen was 7.60 mm (+/- 0.26), range 4.31 to 12.20 mm. The mean mesial bone loss after loading of the final implant was 0.80 mm (+/- 0.26) and the mean distal bone loss was 0.85 mm (+/- 0.25). Conclusion: The two-stage split technique to achieve a gain in width of the residual bone crest is minimally invasive, predictable and the implants placed in the final (definitive) stage have a high survival rate, as we have seen in the present study with 9 years of follow-up.

Routine postdilation after 23 mm Sapien 3 Ultra implantation in the aortic position.

Residual transprosthetic gradient (TG) after transcatheter aortic valve replacement (TAVR) with balloon-expandable valves (BEV) may be due to suboptimal valve expansion. To compare hemodynamics after TAVR with small BEV according to postdilation strategy. This observational, retrospective cohort study included 184 consecutive patients from a single center treated with 23 mm Sapien 3 Ultra (Edwards Lifesciences) BEV implantation in the aortic position and enrolled between January 2020 and April 2023. Patients treated with routine postdilation (RP, n = 73) were compared to patients treated according to local standard practice (SP, n = 111). Primary endpoint was 30-day mean TG. Secondary endpoints were incidence of 30-day prosthesis-patient mismatch (PPM), technical success and device success. Thirty-day mean TG was lower in RP versus SP (12.3 ± 4.6 mmHg vs. 14.1 ± 5.7 mmHg, p = 0.031), and incidence of PPM was less common with RP versus SP (47.3% vs. 71.0%, p = 0.006). Technical success (98.6% vs. 99.1%, p = 0.637) and device success (93.1% vs. 90.1%, p = 0.330) did not differ between groups. Differences in 30-day mean TG were driven by patients at normal flow (12.1 ± 4.0 mmHg vs. 15.0 ± 5.5 mmHg, p = 0.014), while no differences were evident among patients at low flow (12.5 ± 5.5 mmHg vs. 11.7 ± 5.5 mmHg, p = 0.644). RP decreased height and increased width of BEV, and a linear regression established that final BEV width could predict 30-day mean TG (r = -0.6654, p < 0.0001). RP after TAVR with small BEV was associated with more favorable forward-flow hemodynamics than SP.

LOAD-LOADING CAPACITY AND CRACK FORMATION OF REINFORCED CONCRETE CYLINDRICAL SHELL WHEN CHANGING ITS THICKNESS

The results of experimental studies of long cylindrical shells with the aim of determining their stress-strain state, load-bearing capacity and crack resistance when the thickness of the shell changes are described. A special stand was developed by the authors to implement the task. 4 models of a cylindrical shell made of reinforced concrete (samples RC1-RC4) were manufactured and tested. The thickness of the samples was 45, 50, 55, 60 mm, and the cross-sectional dimensions of the side elements were changed accordingly. The distributed load (vertical) was applied in four strips, each 13 cm wide, and only the body of the shell, i.e. the side members were not loaded. The shell hinges from the corners on 100x100mm plates. Inside each side element are two reinforcing rods with a diameter of 10 mm. In order to obtain a complete and reliable picture of the deformation of the shell surface, 4 hour-type indicators are attached to each of the three zones located between the load chains. In addition to indicators, strain gauges were pasted on the shell, which were used to monitor deformations on the upper and lower surfaces. The loading process ended when the tested shell lost its ability to resist the external load. The magnitude of the load corresponding to this moment was taken as the bearing capacity of the shell. Simultaneously with the shell samples, control samples of prisms and cubes were made to determine the physical and mechanical characteristics of concrete. Graphs of the dependence of the relative deformation on the load were constructed. The bearing capacity of the shells and the load at which the first crack formed were determined. By the time of loss of bearing capacity, cracks with the same initial opening width of 0.05 mm had formed in all shells. The final crack opening width, as well as the load-bearing capacity, slightly increased with increasing shell thickness. However, the load at the beginning of crack formation turned out to be the largest for the two average values of the shell thickness – 50 and 55 mm. The general pattern of cracking of all samples is almost the same. The test methodology and the developed stand are universal in nature and will be used for further research.

Anterior Opening-Wedge Proximal Tibial Osteotomy for Slope Correction of Genu Recurvatum

Background: Symptomatic genu recurvatum is defined as greater than 5° of knee hyperextension and can be caused by osseous deformity, soft tissue laxity, or a combination. Common symptoms include pain, weakness, instability, decreased range of motion, leg length discrepancy, and stretching of the posterior capsuloligamentous structures of the knee. In instances where the genu recurvatum is caused by reverse tibial slope, literature supports the use of anterior opening-wedge proximal tibial osteotomy (OW PTO) to treat genu recurvatum by increasing tibial slope. Correction of anterior slope to a more anatomic, posterior orientation allows any stressed ligaments to return to their normal tension and restores the native biomechanics of the knee. Indications: The primary indication for OW PTO is genu recurvatum that is nonresponsive to physical therapy or genu recurvatum with concurrent ligamentous injury. The heel-height test provides an objective assessment for the identification and measurement of knee hyperextension. Technique Description: 2 guide pins are placed parallel to the tibial plateau, engaging the posterior cortex. A small micro sagittal saw is used to cut the anterior cortex. Osteotomes are used to complete the osteotomy, preserving a posterior hinge. An opening spreader device is placed and opened slowly while keeping the posterior cortex intact. The new slope is maintained by use of an opening wedge osteotomy plate and screws. Allograft bone graft is packed thoroughly into the osteotomy site. Fluoroscopy is used throughout the case to assess appropriate orientation and depth of the osteotomy, as well as the final opening width. Results: A review of 5 studies demonstrated adequate reduction in hyperextension, with a mean knee hyperextension ranging from 17° to 32° preoperatively and 0° to 7° postoperatively. Patients had significantly improved postoperative clinical outcomes compared with the preoperative state. Discussion/Conclusion: Anterior OW PTO has been shown to be a safe method of accurately correcting tibial plateau slope for the treatment of genu recurvatum. Patients can expect correction of knee hyperextension, restoration of anatomic posterior tibial slope, decreased posterior tibial translation, and increased subjective outcome scores. Patient Consent Disclosure Statement: The author(s) attest that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

BEARING CAPACITY, DEFORMITY AND CRACK RESISTANCE OF DAMAGED BEAMS REINFORCED WITH FIBER CONCRETE

The results of experimental studies of the load-bearing capacity, deformability and crack resistance of damaged beams reinforced with fiber concrete in the compressed and stretched zone are presented. Test samples are made of concrete and fiber concrete. The amount of steel fiber in fiber concrete is 2% of the volume of the product. Preliminary tests were carried out on prisms and cubes. During the manufacture of beam samples, before concreting, a foam insert was installed in the area of planned damage, the shape and dimensions of which corresponded to the damage. After the concrete set to 70% grade strength, the liner was pulled out, and the resulting cavity was filled with a 2% mixture of fiber concrete. Tests of material samples showed that the introduction of steel fiber into the composition of concrete in the amount of 2% by volume increases the compressive strength limit 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. Conducted experimental studies of damaged beams showed that a beam whose cross-section is 40% damaged in the middle-compressed zone, and the shape of the damage is close to rectangular, has 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. The maximum final crack opening width was 0.6 mm. A beam whose section is 40% damaged in the mid-stretch zone has a load-bearing capacity of 92.4 kN, or 93.2% of the load-bearing capacity of an undamaged beam. Cracking started at the 5th loading stage, when the load was 32.5kN, i.e. 35.2% of the bearing capacity of the damaged beam. The maximum final crack opening width was 0.8 mm. It is claimed that the strengthening of a beam with 40% damage in the compressed or stretched zone in the manner considered in the paper is effective, as it allows achieving its load-bearing capacity, which is more than 93% of the load-bearing capacity of an undamaged beam.

Efficacy of acellular xenogeneic dermal matrix graft in the treatment of multiple gingival recessions: systematic review and meta-analysis.

This study aimed to compare the efficacy of acellular xenogeneic dermal matrix graft (AXDM) compared to connective tissue graft (CTG) in treating multiple gingival recessions. A systematic search of electronic databases was conducted to identify randomized clinical trials (RCTs) that compared AXDM and CTG. The selected studies were subjected to bias risk assessment, data extraction, and meta-analyses. Parameters such as gingival recession height, width, mean percentage of root coverage, and complete root coverage were analyzed. Seven RCTs involving 146 patients were included. The meta-analyses indicated that CTG was statistically superior to AXDM in reducing gingival recession height at the final follow-up (mean difference: -0.104mm, 95% confidence interval [CI]: -0.180-0.028, p = 0.008) and width at the final follow-up (mean difference: -0.285mm, 95% CI: -0.541-0.030, p = 0.029). CTG also demonstrated a significantly higher mean percentage of root coverage at the 6-month follow-up (difference in means: -2.761mm, 95% CI: -4.932-0.590, p = 0.013) and a higher percentage of complete root coverage at the 6-month follow-up (odds Ratio [OR]: 0.598, 95% CI: 0.4-0.892, p = 0.012) compared to AXDM. However, there was no significant difference in the number of teeth with complete root coverage between CTG and AXDM (OR: 1.610, 95% CI: 0.983-2.636, p = 0.058) and aesthetic outcomes (mean difference: 0.148, 95% CI: -0.277-0.573, p = 0.494). CTG is more effective than AXDM in treating multiple gingival recessions. This is evidenced by significant reductions in gingival recession height and width, a higher mean percentage of root coverage, and a greater percentage of complete root coverage at the 6-month follow-up. In some clinical situations an alternative to CTG is required for the treatment of multiple gingival recessions. AXDM, despite presenting clinical outcomes that are not as satisfactory as CTG, can be used for this purpose.

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.

Shortcuts to adiabatic soliton compression in active nonlinear Kerr media.

We implement variational shortcuts to adiabaticity for optical pulse compression in an active nonlinear Kerr medium with distributed amplification and spatially varying dispersion and nonlinearity. Starting with the hyperbolic secant ansatz, we employ a variational approximation to systematically derive dynamical equations, establishing analytical relationships linking the amplitude, width, and chirp of the pulse. Through the inverse engineering approach, we manipulate the distributed gain/loss, nonlinearity and dispersion profiles to efficiently compress the optical pulse over a reduced distance with high fidelity. In addition, we explore the dynamical stability of the system to illustrate the advantage of our protocol over conventional adiabatic approaches. Finally, we analyze the impact of tailored higher-order dispersion on soliton self-compression and derive physical constraints on the final soliton width for the complementary case of soliton expansion. The broader implications of our findings extend beyond optical systems, encompassing areas such as cold-atom and magnetic systems highlighting the versatility and relevance of our approach in various physical contexts.

Investigating the Non-Linear Effects of Breach Parameters on a Dam Break Study

AbstractWhen settlements are located close to a dam, it is important to accurately predict the breach peak flow and the time to reach the peak. Therefore, the prediction of dam breach properties is essential in dam break studies. Dam breach parameters such as the breach side slope, final bottom width, final bottom elevation, weir coefficient, breach formation time, and initial elevation of reservoirs are the key variables for estimating the peak discharge during a dam break scenario. In this study, these six breach parameters were analyzed to investigate the impact of breach parameters on breach peak flow and the time to reach the peak. Thus, several scenarios were calculated and compared for Atasu Dam. The results revealed that the role of the initial water elevation, final bottom elevation, and breach development time had more of an impact on the breach peak flow and the time to reach the peak. In addition, the study indicated that the final bottom width and breach weir coefficient were less sensitive to both the peak discharge and peak discharge time. Furthermore, the analysis indicated that the breach side slope parameter had no major influence on the time to peak while also having an insignificant impact on the peak discharge. Understanding this breach mechanism provides a basis for relevant research in designating key parameters for dam break analysis. Thus, the results can contribute to decision making toward the design of flood mitigation and dam emergency action planning.

Chemical Control of Powdery Mildew of Bigleaf Hydrangea

The efficacy of the fungicide pydiflumetofen + difenoconazole (Postiva) was evaluated at varying application rates and intervals for the control of powdery mildew (Golovinomyces orontii, formerly Erysiphe polygoni) in bigleaf hydrangea (Hydrangea macrophylla ‘Nikko Blue’). Container-grown hydrangeas were arranged in a completely randomized design with six single-plant replications. Experiments were done in 2022 and 2023 under both greenhouse and shade house conditions (56% shade). Powdery mildew in hydrangea was developed naturally. Pydiflumetofen + difenoconazole at 1.1, 1.6, and 2.2 ml·L−1 and a standard fungicide azoxystrobin + benzovindiflupyr (Mural) at 0.5 g·L−1 were sprayed to runoff on 2-, 4-, and 6-week intervals. Plants that were not treated with fungicide served as the control. Plants were evaluated weekly for disease severity (0% to 100% foliage affected) and defoliation (0% to 100% defoliation). The season-long area under the disease progress curve (AUDPC) and defoliation progress curve (AUDFC) were calculated for the evaluation period. The initial and final plant height and width were recorded, and height and width increase were determined. Pydiflumetofen + difenoconazole and azoxystrobin + benzovindiflupyr significantly reduced final disease severity, AUDPC, and defoliation both in the greenhouse and shade house compared with control plants. In both greenhouse trials and the 2022 shade house trial, AUDFC was reduced in all treatments compared with the control plants. However, AUDFC was not reduced by all treatments in the 2023 shade house trial. Pooled over application intervals, the low rate of pydiflumetofen + difenoconazole was as effective as the medium and high rates of pydiflumetofen + difenoconazole and azoxystrobin + benzovindiflupyr in reducing final powdery mildew severity and AUDPC both in the greenhouse and shade house in both 2022 and 2023. No significant differences between application intervals were noted in final disease severity and progress. Control of powdery mildew with fungicides failed to increase plant dimensions (i.e., plant height and width) compared with the no fungicide control. Because all application rates and intervals of pydiflumetofen + difenoconazole provided comparable powdery mildew disease control, it is suggested that using a low rate of pydiflumetofen + difenoconazole with the longest application interval (6 weeks) is the most cost-effective approach for managing powdery mildew in bigleaf hydrangeas.

Performance of Holstein dairy calves fed starter diet with incremental vinasse proportion

This experiment evaluated the progressive inclusion of vinasse in calf starter diet on performance, rumen fermentation, and blood metabolites. Forty-eight Holstein calves weighing an average of 41.5 ± 2.20 kg were used in a completely randomized design and assigned to 4 dietary groups: no vinasse inclusion (V0), 4% of dry matter (DM) vinasse inclusion (V4), 8% of DM vinasse inclusion (V8), and 12% of DM vinasse inclusion (V12). Each treatment group comprised 12 calves that were balanced for sex of calves. Vinasse was added to the starter feed to replace soybean meal and wheat bran. Calves were gradually weaned from day 64 to 70, and the experiment continued until day 90. Starter feed, total DM, and metabolizable energy intakes during the post-weaning and overall periods responded cubically to vinasse inclusion level, and the greatest intakes were observed in V8-fed calves. As the dietary inclusion of vinasse increased, average daily gain (ADG) increased linearly, quadratically, and cubically during pre-weaning, post-weaning and overall periods, respectively. This resulted in pre-weaning and overall feed efficiency (FE) increasing linearly, and post-weaning FE tended to increase linearly with increasing inclusion level of vinasse in the starter diet. Weaning body weight (BW) tended to increase and final BW increased linearly as the dietary inclusion of vinasse increased. Weaning and final hip width responded quadratically, with V4-fed calves showing the greatest values. Weaning and final body barrel decreased linearly and tended to decrease linearly, respectively, as the dietary inclusion of vinasse increased in the starter diet. Ruminal pH on day 45 was not different among treatments, but pH on day 85 responded quadratically, with the highest pH observed in V8-fed calves. Ammonia and total VFA concentrations (days 45 and 85) were not different across treatments. Acetate concentration on day 85 increased linearly from 50.3 to 55.5 mol/100 mol, as vinasse proportion increased from 0 to 12% of DM in the calf starter, but the inverse trend was observed with propionate molar proportion. Butyrate, isobutyrate, and isovalerate concentrations measured on day 45 were not different among treatments, but the lower values on day 85 were observed with V4 and V8-fed calves. Blood metabolites on days 60 and 80 remained unaffected between treatments. In conclusion, vinasse is recommended at 8% of DM in the calf starter diet as this level improved calf performance and rumen fermentation.

EXPERIMENTAL STUDIES ON THE STRENGTHENING OF A BEAM DAMAGED IN THE TENSILE ZONE

The paper presents the results of a study of the bearing capacity of a beam damaged during hostilities, which was reinforced with steel-reinforced concrete. Consider a beam with 40% damage in the stretched zone. 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. This is one of the options for beam strengthening in a complex program of testing damaged beams, which involves the study of a series of beams with different types of damage, the damage zone (tension and compression) and its dimensions, geometry and method of strengthening. For testing, the authors developed a special stand. The plane-transverse load bending of the beam under study is created with the help of a hydraulic jack and a metal I-beam with a traverse, which transmits two equally concentrated forces to the beam. The generated load is controlled by a model dynamometer of the Tokar system and a ring dynamometer, which acts as a support. Experimental studies have established that a beam whose cross-section is 40% damaged in the middle stretched zone, and the shape of the damage is close to rectangular, has a bearing capacity of 91.0 kN, which is 92.38% of the bearing capacity of an intact beam (98.5 kN ). Cracking started at the 5th loading stage, when the load value was 32.5kN, i.e. 35.7% of the bearing capacity of the damaged beam. At the same time, 4 cracks were formed. At the sixth stage, three more cracks appeared. At stages 9-12 of loading, 9 more cracks formed. The maximum final crack opening width was 1.1 mm. At the same time, 6 cracks formed in the zone of clean bending. During the entire testing process, the fiber concrete liner worked with the beam as a single unit. It can be argued that the strengthening of a beam with 40% damage in the stretched zone in the manner considered in the paper allows to achieve its bearing capacity, which is 92.38% of the bearing capacity of an undamaged beam.

DEFORMABILITY AND CRACK RESISTANCE OF REINFORCED CONCRETE AND FIBER CONCRETE BEAMS

The work presents the results of the study of deformability and crack resistance of reinforced concrete beams with additional steel fiber reinforcement. Beam samples of three series were produced (three in each series): series I ― beams made of ordinary concrete; II series ― steel-reinforced concrete beams; III series ― beams of combined section, in which the lower zone (0.5 from the height of the beam) is made of steel fiber concrete, and the upper zone is made of ordinary concrete. One sample of each series was made from one batch. At the same time, material samples were made from the same batch. Fiber, the total volume of which was 1% of the volume, was uniformly added to the composition of the concrete mass for the II and III series of samples during mixing. The load was applied in increments of 1 ton. Deformations were determined using strain gauges, watch-type indicators with a division value of 0.01 mm in the middle of the beam span. At each stage, a certain amount of time was required to read the instruments, find and fix the cracks, as well as to measure the length and width of their opening using a Brinell tube. The tests showed that the deformability of the beams of the three series and the character of the crack formation are significantly different from each other. Moreover, the series III beam with combined reinforcement occupies an intermediate position in terms of these characteristics. Thus, by the end of the tests, the reinforced concrete beam (series I) had 19 cracks, the fiber concrete beam (series II) ― 28, the beams with combined reinforcement (series III) ― 23. At the same time, the maximum final crack opening width for beams I, II, III series was 0.8 mm, 0.1 mm (one crack) and 0.1 mm (two cracks), respectively. Cracks in a fiber concrete beam are much smaller in width. And the maximum length of the cracks here turned out to be the largest ― 31.3 cm, while in the beams of the I and III series this value was 25.5 cm and 20.4 cm, respectively.&#x0D; The analysis of the given results shows that the best indicators of crack resistance are revealed by beams with full dispersion reinforcement. The use of fiber allows you to change the nature of the destruction process. Unlike ordinary concrete, in which this process occurs almost instantaneously, in fiber concrete there is no brittle failure, and the beam continues to resist the load, and the nature of the failure changes from brittle to viscous.

EXPERIMENTAL STUDIES OF A DAMAGED BEAM REINFORCED WITH FIBER CONCRETE

The paper presents the results of a study of the load-bearing capacity of a beam damaged during hostilities, which was reinforced with steel fiber concrete. A beam with 20% damage in the compressed zone is considered. Before concreting, a foam liner was installed in the area of the planned damage, the shape and dimensions of which corresponded to the planned damage. After the concrete gained 70% of the brand strength, the liner was removed, and the resulting cavity was filled with a 2% mixture of fiber-reinforced concrete. This is one of the options for strengthening a beam in a comprehensive testing program for damaged beams, which involves studying a series of beams with different types of damage, damage zone (tension and compression) and its size, geometry and method of strengthening. The authors have developed a special stand for testing. Plane transverse bending of the loading of the beam under test is created using a hydraulic jack and a metal I-beam with a traverse that transmits two equal concentrated forces to the beam. The created load is controlled by an exemplary dynamometer of the Tokar system and a ring dynamometer, which acts as a support. Experimental studies have shown that a beam, the cross-section of which is 20% damaged in the middle compressed zone, and the shape of the damage is close to rectangular, has a load-bearing capacity of 93.6 kN, which is 95.0% of the load-bearing capacity of an undamaged beam (98.5 kN). Crack formation began on the 5th stage of loading, when the load value was 32.5 kN, that is, 34.7% of the load-bearing capacity of the damaged beam. In this case, 4 cracks formed in the pure bending zone. At the sixth stage, three more cracks appeared. At stages 9, 10 and 14 of loading, 7 more cracks formed. The maximum final crack opening width was 0.8 mm. throughout the testing process, the fiber-reinforced concrete liner worked with the beam as a single unit. It can be argued that strengthening a beam with 20% damage in the compressed zone using the method considered in the work makes it possible to achieve its load-bearing capacity, which is 95% of the load-bearing capacity of an undamaged beam.

BEARING CAPACITY OF A BEAM DAMAGED DURING COMBAT ACTIONS STRENGTHENED WITH THE USE OF FIBER CONCRETE

The paper presents the results of a study of the load-bearing capacity of a beam damaged during hostilities, which was reinforced with steel-reinforced concrete. A beam with 20 percent damage in the compression zone is considered. Before concreting, a foam insert was installed in the area of the planned damage, the shape and dimensions of which corresponded to the planned damage. After the concrete was set to 70% grade strength, the liner was pulled out, and the resulting cavity was filled with a 2% mixture of fiber concrete. This is one of the beam strengthening options in a comprehensive damaged beam testing program, which involves the study of a series of beams with different types of damage, varying damage zone (tensile and compression) and its magnitude, geometry and method of strengthening. The authors developed a special stand for testing. The load-bearing capacity of the damaged beam reinforced with fiber concrete was 80.6 kN, or 89.5% of the load-bearing capacity of the intact beam. Cracking started at the 4th load stage, when the load value was 16.1 kN, or 20% of the bearing capacity of the damaged beam. At the same time, 10 cracks formed in the zone of pure bending, the opening width of which did not exceed half the price of the microscope division, which is 0.005 mm. At the next eight stages of loading (up to 48.4kN), no new cracks were observed, and the width of the opening of all the ones that had previously formed doubled - it reached 0.01mm. At the 12th, 13th and 19th stages of loading, 4 more cracks appeared. The maximum final crack opening width was 1.2 mm. Up to a load of 68.5kN, which is 85% of the load-bearing capacity of the damaged beam, the reinforced concrete liner works with the beam almost as a unit, and then the compressed zone of concrete squeezes out the liner. It is claimed that the strengthening of a beam with 20% damage in the compressed zone in the manner considered in the work allows to achieve its bearing capacity, which is almost 90% of the bearing capacity of an undamaged beam.

Development of a LINAC head model for the CyberKnife VSI-System using EGSnrc Monte Carlo system.

In order to understand the interaction processes of photons and electrons of the CyberKnife VSI-System, a modeling of the LINAC head must take place. Here, a Monte Carlo simulation can help. By comparing the measured data with the simulation data, the agreement can be checked. For the Monte Carlo simulations, the toolkit EGSnrc with the user codes BEAMnrc and DOSXZYnrc was used. The CyberKnife VSI-System has two collimation systems to define the field size of the beam. On the one hand, it has 12 circular collimators and, on the other, an IRIS-aperture. The average energy, final source width, dose profiles, and output factors in a voxel-based water phantom were determined and compared to the measured data. The average kinetic energy of the electron beam for the CyberKnife VSI LINAC head is 6.9 MeV, with a final source width of 0.25cm in x-direction and 0.23cm in y-direction. All simulated dose profiles for both collimation systems were able to achieve a global gamma criterion of 1%/1mm to the measured data. For the output factors, the deviation from simulated to measured data is<1% from a field size of 12.5mm for the circular collimators and from a field size of 10mm for the IRIS-aperture. The beam characteristics of the CyberKnife VSI LINAC head could be exactly simulated with Monte Carlo simulation. Thus, in the future, this model can be used as a basis for electronic patient-specific QA or to determine scattering processes of the LINAC head.