Volume Removal Research Articles

Fundamental study on dielectric oil viscosity for high-performance wire EDM

AbstractDielectric oil has been recently used in wire electrical discharge machining (wire EDM) for achieving high-precision machining. However, the influence of dielectric oil properties on wire EDM characteristics has not been clarified sufficiently. This study fundamentally investigated the influence of dielectric oil viscosity on wire EDM characteristics. In this study, three types of dielectric oil differing only in viscosity were prepared and examined. Linear cutting experiment results showed that the removal rate and the machined surface roughness increase with dielectric oil viscosity. Then, the influence of viscosity on crater removal volume was investigated to discuss the cause of the change in removal rate, and it was found that crater removal volume increases with the viscosity. Furthermore, CFD (computational fluid dynamics) analysis results and discharge observation results showed that the debris exclusion becomes worse in higher viscosity oil, and the discharge concentration occurs frequently, resulting in the deterioration in machined surface roughness. Next, the difference in machining accuracy with dielectric oil viscosity was investigated. It was found that the corner shape accuracy deteriorates with the increase of viscosity while the machined surface waviness and straightness improve slightly. Structural analysis results showed that wire deflection increases with viscosity, resulting in the deterioration in corner shape accuracy. On the other hand, high-speed observation of wire vibration was carried out, and it was found that the wire vibration decreases in the case of higher viscosity, which leads to the improvement in machined surface waviness and straightness.

High-Speed Removal Process for Organic Polymers by Non-Thermal Atmospheric-Pressure Spark Discharge at Room Temperature and Its Mechanism

Heel marks (HMs) are a type of dirt stain consisting of polyester-based urethane rubber on polyvinyl chloride (PVC) floor surfaces. The rapid removal of HMs was achieved by using non-thermal atmospheric-pressure plasma technology. Mimetic HMs were prepared by coating PVC floor samples with HMs to a thickness of 13.9 μm. The removal area, thickness, and volume were measured after applying spark discharges at high voltage and a repetition rate of 50 kHz. The treated surfaces were analyzed by using X-ray photoelectron spectroscopy (XPS) and pyrolysis–gas chromatography with time-of-flight mass spectrometry (Py-GC/TOFMS). Removal rates of 20 mm2/min in area, 52 mm3/min in volume, and 7 μm/min in depth were achieved with an inter-electrode distance of 10.0 mm and an air flow rate of 20 standard liters per minute. A removal depth of 10 μm/min was achieved without air supply. The mechanism of stain removal by spark discharge was modeled by decomposing the original high-molecular-weight molecules in polyester-based urethane rubber into low-molecular-weight molecules, such as methylene diisocyanate (MDI) components. The results of this study may facilitate the development of a novel electric vacuum cleaner capable of removing floor stains.

Taming hemoglobin chemistry-a new hemoglobin-based oxygen carrier engineered with both decreased rates of nitric oxide scavenging and lipid oxidation.

The clinical utility of hemoglobin-based oxygen carriers (HBOC) is limited by adverse heme oxidative chemistry. A variety of tyrosine residues were inserted on the surface of the γ subunit of recombinant fetal hemoglobin to create novel electron transport pathways. This enhanced the ability of the physiological antioxidant ascorbate to reduce ferryl heme and decrease lipid peroxidation. The γL96Y mutation presented the best profile of oxidative protection unaccompanied by loss of protein stability and function. N-terminal deletions were constructed to facilitate the production of recombinant hemoglobin by fermentation and phenylalanine insertions in the heme pocket to decrease the rate of NO dioxygenation. The resultant mutant (αV1del. αL29F, γG1del. γV67F, γL96Y) significantly decreased NO scavenging and lipid peroxidation in vitro. Unlike native hemoglobin or a recombinant control (αV1del, γG1del), this mutation showed no increase in blood pressure immediately following infusion in a rat model of reperfusion injury, suggesting that it was also able to prevent NO scavenging in vivo. Infusion of the mutant also resulted in no meaningful adverse physiological effects apart from diuresis, and no increase in oxidative stress, as measured by urinary isoprostane levels. Following PEGylation via the Euro-PEG-Hb method to increase vascular retention, this novel protein construct was compared with saline in a severe rat reperfusion injury model (45% blood volume removal for 90 minutes followed by reinfusion to twice the volume of shed blood). Blood pressure and survival were followed for 4 h post-reperfusion. While there was no difference in blood pressure, the PEGylated Hb mutant significantly increased survival.

Investigation on 2D SiCf/SiC composite scribing mechanism by single- and double-grit

To validate the proposed removal mechanism of 2D SiCf/SiC composite, single- and double-grit scribing experiments were conducted on the fiber woven surface (WS) and stacking surface (SS) along the 0°, 45°, and 90°. The results indicate that transverse fibers mainly undergo shear, tensile, and bending fractures. The removal modes of normal fibers are shear and bending fractures. The longitudinal fibers are damaged by tensile (cut-in side) and bending (cut-off side) fractures, accompanied by fiber peel-off. The removal forms of the matrix include crack propagation, ductile scratch, powdery removal, and brittle peel-off. The order of scribing force is FSS0 > FWS45 > FSS90 > FWS0. The maximum and minimum scribing force occur on SS0 and WS0, respectively, due to the powdery removal of matrix and fibers + matrix peel-off. The 2nd grit scribes the matrix layer and fiber tip in a very low depth to cause powdery and ductile removal, which exhibit the different material removal mechanism with the 1st grit. The scribing damage formed by 1st grit greatly reduces the force required by the 2nd grit for the same material removal volume. The coupling effect among grits in multi-grit scribing and grinding cannot be ignored.

A Fluorescence-based Method to Reaccess Root Canals in Endodontically Treated Teeth: A Micro–Computed Tomography Tridimensional Assessment

IntroductionThe aim of this study was to evaluate the volume of dentin removal and the volume of remnants of restorative material after the removal of an esthetic restorative coronal set and cervical barrier in endodontically treated mandibular molars with the aid of different magnification methods using 3-dimensional (3D) micro–computed tomographic (micro-CT) morphometric analysis. MethodsA sample of 30 mandibular first molars (N = 30) was used. All teeth were endodontically treated, and the specimens were initially scanned using micro-CT imaging and reconstructed. The molars were filled by a single-cone technique, and immediately the material at the initial 2-mm cervical level was removed. Cervical barriers were confected using ionomer glass cement with fluorescein 0.1%, filling the 2 mm at the cervical level of the canals and an additional 2 mm as the base. The coronal restoration set was performed using esthetic resin composites. A simulated tooth aging process was performed with 20,000 thermocycling cycles. The sample was distributed into the following 3 groups (n = 10) for the removal of the restoration set and cervical barrier with diamond burs based on the magnification aid: no magnification aid (naked eye), operative microscope aid, and REVEAL device (Design for Vision Inc, Bohemia, NY) aid. After removal, the final 3D micro-CT scanning and reconstruction were conducted with the same parameters as the initial scanning, and superposition of the final and initial scanning was performed. Morphometric analysis was conducted using CTAn software (Bruker microCT, Kontich, Belgium) to assess the volume of remnant restorative material (mm³), the volume of dentin removal (mm³), and the direction and site of dentin removal. Data were analyzed using 1-Way analysis of variance (P < .05). ResultsThe REVEAL group showed better results regarding the volume of remnant material (3.17 ± 1.65) and the percentage of dentin removal (2.56 ± 1.34). The microscope group showed no statistical difference compared with the REVEAL group regarding dentin removal (3.30 ± 1.48) and was statistically similar to the naked eye group in the volume of remnant material (9.63 ± 4.33). The naked eye group showed the worst results for the volume of remnant material (7.60 ± 2.68) and the percentage of dentin removal (6.60 ± 3.70). ConclusionsThe use of fluorescence associated with magnification was the method that presented the best results, with lower percentages of dentin removal and smaller volumes of remaining restorative material. This is an innovative technology in endodontics that shows potential to overcome the challenge of reaccessing root canals in the context of endodontic retreatment.

Mapping model of ribbon contour and tool influence function based on distributed parallel neural networks in magneto-rheological finishing

Magnetorheological finishing (MRF) stands out as a notable polishing technology, characterized by high precision and minimal damage. However, establishing an accurate and practical model for the tool influence function (TIF) of MRF poses a significant challenge. In this paper, a TIF modeling method of MRF based on distributed parallel neural networks is proposed for the first time. Assessment of the viability of this approach through multiple sets of robot-assisted MRF experiments is detailed. The experimental results conclusively demonstrate the successful intelligent prediction of TIF, with key indicators such as volume removal rate and peak removal rate achieving an average prediction accuracy exceeding 95%. This method can remarkably advance the intelligence of the TIF model in MRF and serve as a valuable reference for other optical fabrication methods.

3-Dimensional Printed Model of the Temporal Bone for Neurosurgical Training.

The development of neurosurgical skills stands out as a paramount objective for neurosurgery residents during their formative years. Mastery of intricate and complex procedures is a time-intensive process marked by a gradually ascending learning curve. Consequently, the study and simulation on surgical models assume significant importance. One of the most intricate neuroanatomical regions includes the petrous and mastoid portions of the temporal bone. These regions host critical, highly functional, and vital neurovascular structures, including the facial nerve, cochlea, semicircular canals, internal carotid artery, and middle ear. This fully open-source 3-dimensional (3D) model of the temporal bone, created for educational purposes, should be easily and economically reproducible using a 3D printer, offering all residents the opportunity to understand the spatial location, three-dimensional anatomical structures, and fundamental intricacies of mastoidectomy. A 3D model of the temporal bone was fabricated using a computed tomography (CT) scan derived from an actual human body. The CT scan of the model was meticulously juxtaposed with the reference sample CT scan. Neurosurgical residents were recruited as participants for this study. Each participant was tasked with executing a mastoidectomy on 2 separate occasions, with a 2-week interval between attempts. Throughout these sessions, various parameters, including the time taken for task completion, the volume of bone removal, and any potential complications, were systematically registered. The mean volume of bone removed increased by 34.5%, and the mean task time and the mean number of complications decreased by 10.3% and 25%, respectively, during the training. Engaging in training with cost-effective anatomical models constitutes a valuable tool for refining technical skills during residency. We posit that this type of model training should be incorporated as part of the trainee's curriculum during the residency program because of the myriad advantages evidenced by the findings of this study.

Measures of wave intensity as a non-invasive surrogate for cardiac function predicts mortality in haemodialysis patients.

Risk prediction in haemodialysis (HD) patients is challenging due to the impact of the dialysis regime on the patient's volume status and the complex interplay with cardiac function, comorbidities and hypertension. Cardiac function as a key predictor of cardiovascular (CV) mortality in HD patients is challenging to assess in daily routine. Thus the aim of this study was to investigate the association of a novel, non-invasive relative index of systolic function with mortality and to assess its interplay with volume removal. A total of 558 (373 male/185 female) HD patients with a median age of 66years were included in this analysis. They underwent 24-hour ambulatory blood pressure monitoring, including wave intensity analysis [i.e. S:D ratio (SDR)]. All-cause and CV mortality served as endpoints and multivariate proportional hazards models were used for risk prediction. Intradialytic changes were analysed in tertiles according to ultrafiltration volume. During a follow-up of 37.8months, 193 patients died (92 due to CV reasons). The SDR was significantly associated with all-cause {univariate hazard ratio [HR] 1.36 [95% confidence interval (CI) 1.20-1.54], P<.001} and CV [univariate HR 1.41 (95% CI 1.20-1.67), P<.001] mortality. The associations remained significant in multivariate analysis accounting for possible confounders. Changes in the SDR from pre-/early- to post-dialytic averages were significantly different for the three ultrafiltration volume groups. This study provides well-powered evidence for the independent association of a novel index of systolic function with mortality. Furthermore, it revealed a significant association between intradialytic changes of the measure and intradialytic volume removal.

Critical upper gastrointestinal bleeding secondary to pine stall shaving ingestion and mechanical gastritis in a young do

AbstractAn 8‐month‐old, male, entire Staffordshire terrier was presented for acute lethargy. The patient was severely anaemic. Diagnostic and clinical findings indicated severe upper gastrointestinal haemorrhage of unknown aetiology. Large‐volume transfusion (a total of 64.2 mL/kg of blood product) and medical management resulted in fleeting stabilisation. Serial imaging documented persistent non‐obstructive foreign material within the stomach. Due to continued gastrointestinal haemorrhage, failure to respond to medical management, and the persistent abnormal material within the stomach, surgical exploration was recommended. Exploratory laparotomy and gastrotomy resulted in the removal of a large volume of pine stall shavings. There was gross evidence of diffuse mucosal haemorrhage and mechanical gastritis. No additional blood product was required following gastrotomy. To the authors’ knowledge, this is the first case report of a dog with critical bleeding necessitating large‐volume transfusion due to mechanical gastritis from ingestion of pine stall shavings, a material which is typically considered innocuous.

Portal Vein Doppler Is a Sensitive Marker for Evaluating Venous Congestion in End-Stage Kidney Disease

Introduction: Determining ultrafiltration volume in patients undergoing intermittent hemodialysis (IHD) is an essential component in the assessment and management of volume status. Venous excess ultrasound (VExUS) is a novel tool used to quantify the severity of venous congestion at the bedside. Given the high prevalence of pulmonary hypertension in patients with end-stage kidney disease (ESKD), venous Doppler could represent a useful tool to monitor decongestion in these patients. Methods: This is a prospective observational study conducted in ESKD patients who were admitted to the hospital requiring IHD and ultrafiltration. Inferior vena cava maximum diameter (IVCd), portal vein Doppler (PVD), and hepatic vein Doppler (HVD) were performed in all patients before and after a single IHD session. Results: Forty-one patients were included. The prevalence of venous congestion was 88% based on IVCd and 63% based on portal vein pulsatility fraction (PVPF). Both mean IVCd and PVPF displayed a significant improvement after ultrafiltration. The percent decrease in PVPF was significantly larger than the percent decrease in IVCd. HVD alterations did not significantly improve after ultrafiltration. Conclusions: Our study revealed a high prevalence of venous congestion in hospitalized ESKD patients undergoing hemodialysis. After a single IHD session, there was a significant improvement in both IVCd and PVPF. HVD showed no significant improvement with one IHD session. PVPF changes were more sensitive than IVCd changes during volume removal. This study suggests that, due to its rapid response to volume removal, PVD, among the various components of the VExUS grading system, could be more effective in monitoring real-time decongestion in patients undergoing IHD.

Sustainable use of waste glass sand and waste glass powder in alkali-activated slag foam concretes: Physico-mechanical, thermal insulation and durability characteristics

In many countries, the safe removal of the massive volume of waste glass has emerged as a major environmental priority. However, the manufacture of concrete pollutes the environment with greenhouse gasses and consumes vast amounts of natural resources. As a result, the construction industry has recently been paying more and more attention to reusing glass waste to produce environmentally friendly building materials. This work aims to manufacture environmentally friendly alkali-activated foam concrete (AAFC) by examining the combined effects of waste glass powder (GP) and waste glass sand (GS) as partial substitutes for granulated blast-furnace slag (GBFS) and river sand (RS) respectively. The present study involved the experimentation of AAFC mixtures with GP contents of 0 and 10 % as a replacement for GBFS and GS contents of 0, 25, 50 and 100 % as a replacement for RS. Eight AAFC mixtures with fixed alkaline solution-to-binder (A/B) ratio of 0.5 were fabricated and cured at 80 °C for 24 h. The effects of different GS and GP contents on the oven dry density, flowability, water absorption, porosity, sorptivity, thermal conductivity, compressive strength, flexural strength, high temperature resistance and hydrochloric acid (HCI) resistance of AAFC mixtures were evaluated. Microstructure of the mixtures was analyzed by SEM and EDS. The findings indicated that the AAFC mixture with 50 % GS exhibited the best mechanical properties with a compressive strength of 3.48 MPa, representing a 71.4 % increase over the reference mixture. The mixture with 50 %GS also exhibited the lowest sorptivity regardless of GP content. Thermal conductivity enhanced by 4.6 and 7.0 % by replacing RS with 50 % GS at 0 and 10 % GP content. Replacing RS with GS and GBFS with GP increased the high temperature and acid resistance of the AAFC mixtures and the best high temperature and acid resistance were obtained for the mixtures containing 100 %GS and 10 %GP.

Research on the removal mechanism and surface damage of laser assisted cutting of CFRP materials

The material removal mechanism of carbon fiber reinforced polymer (CFRP) in the process of laser assisted cutting (LAC) is still unclear. This study adopts a simulation and experimental methods to reveal the material removal mechanism of CFRP under the thermal-mechanical coupling effect. The cutting force, cutting temperature, and surface morphology are also analyzed through orthogonal cutting experiments. The experimental results show that the cutting force at various angles is significantly reduced due to enhancements in fiber fracture mode and a decrease in material removal volume with the laser assistance. The most substantial reduction, at 75.3 %, is observed in the feed cutting force at a 135° cutting angle. Additionally, the cutting temperature remains steady at approximately 55 °C, with no damage to the substrate in the laser assisted cutting. A three-dimensional finite element model of laser assisted orthogonal cutting was established innovatively by considering the bare fiber leakage to simulate the laser assistance. Based on this model, the fracture evolutionary mechanism of fibers and resins under laser irradiation is characterized. Laser assisted cutting experiments were conducted, and the simulation results were consistent with the experimental cutting force error within 20 %. The substrate damage and surface morphology were consistent with the experimental results. It is found that the bonding effect of the resin is significantly weakened due to being ablated in laser assisted cutting, making the fibers more prone to shear fracture. The proportion of fiber extrusion fracture under 90° cutting angle in laser assisted orthogonal cutting decreases, the crack damage is small and the fracture point of fiber bending is higher than that of conventional cutting. In addition, the effect of the laser on fiber fracture is more significant when the cutting angle is 135°, and it is more helpful for improving the fiber fracture mode with an increasing cutting speed when the cutting angle is 90°.

SDS and TX-100 performance in removing Cd ion from contaminated sand in flushing column

In this study, contaminated sand by cadmium (Cd2+) ion was cleansed by surfactant foam in a flushing column. The ability to remove Cd2+ ion on the sand surface influenced by the surfactant's properties. The Sodium dodecyl sulfate (SDS) as an anionic surfactant was compared with Triton X-100 (TX-100) non anionic surfactant in their ability to remove the metal ion on the sand surface in the flushing column. The loading time, surfactant concentration, and flow rate of the surfactant were then investigated to confirm the charging effect of surfactant in the ability to remove metal ions. The results show that SDS has a higher ability than TX-100 to remove the Cd2+ ion on the sand surface. The optimal removal efficiency by SDS was 52 %, and TX 100 was 47 %. The loading time impacted surfactant interaction with metal ions in the column, showing that a longer loading time will increase the removal efficiency. Increased concentration of surfactants and more prolonged initial flushing tend to remove higher metal ions, indicating that the residual metal ion was flushing out on the first four pore volume removals. Flushing in a column with foam by anionic surfactant shows a higher ability to remove metal ions on the sand surface.

Management and Outcomes of Kidney Transplant Candidates With Severe Pulmonary Hypertension: A Single-center Strategy and Experience.

Severe pulmonary hypertension (PH) is associated with high mortality posttransplant and thus is considered a contraindication to kidney transplantation. In this study, we describe the pretransplant management and posttransplant outcomes in patients with severe PH using a multidisciplinary approach. Between 11 of 2013 and 8 of 2022, we identified all patients with severe PH on initial pretransplant workup who underwent ultrafiltration (UF) or medical therapy for PH before transplant. Posttransplant we evaluated the perioperative course, renal function, graft, and patient survival. We compared survival to those who remained waitlisted or were delisted. Three-two patients (mean age = 55.03 ± 10.22 y) diagnosed with severe PH on pretransplant screening echocardiogram. Thirty patients (94%) were subjected to a median of 4 (range, 3-8) UF sessions with an average weight loss of 4.33 ± 2.6 kg. Repeat assessment of PH revealed a decline in mean pulmonary artery systolic pressure from 67 ± 12 mm Hg to 43 ± 13 mm Hg (P < 0.0001). Seventeen patients (53%) received a kidney transplant. The mean estimated Glomerular Filtration Rate at 3, 6, 9, and 12 mo was 72 ± 27, 72 ± 28, 75 ± 29, and 75 ± 29 mL/min/1.73 m2. Among, those who underwent transplantation both graft and patient survival was 100% at 1-y posttransplant. Overall, since the UF intervention, at a median follow-up of 88 ± 12 mo those transplanted had a patient survival of 88% while those who remained on dialysis had a survival of 53% (P = 0.0003). In this single-center study, we report postcapillary PH can be a significant contributor to elevations in pulmonary artery systolic pressure. Using a multidisciplinary approach, PH can improve with volume removal and phosphodiesterase 5 inhibitors therapy leading to a successful posttransplant outcome.

Surface roughness evolution law in full-aperture chemical mechanical polishing

Ultra-high precision revolution surfaces are crucial to mechanical components like bearings but are difficult to achieve using conventional machining. Meanwhile, it is challenging to predict the surface roughness evolution law during processing. Accordingly, this study proposed an ultra-precision full-aperture chemical mechanical polishing (CMP) method for processing revolution surfaces. More importantly, a theoretical surface roughness Ra model was established by assuming that the three-dimensional surface morphology can be simplified to two-dimensional identical triangles, each peak can be uniformly removed, and the material removal at the valleys can be neglected compared to that at the peaks. The model provides an intuitive understanding of the Ra evolution law during the full-aperture CMP. Interestingly, Ra first decreases parabolically, determined by the initial surface roughness Ra0, the material volume removal rate MRRV, and the polishing time t. Then, it stabilizes. In addition, the theoretical MRRV model was summarized. The cylindrical guiding surface of a bearing was polished with the developed full-aperture CMP method. In 6 min, Ra can be significantly reduced from the initial 201.09 nm to 1.50 nm almost parabolically and stabilizes. Experimental results basically validate the theoretical Ra model, except that a slow decreasing stage appears intermediately because the real surface cannot be perfectly uniform. Additionally, the roundness error RONt is reduced by 34 %. Furthermore, the full-aperture CMP method and Ra model are successfully applied to other revolution surfaces. This study provides mechanistic insight into Ra evolution modelling pertaining to the manufacturing process.

Portal vein Doppler tracks volume status in patients with severe tricuspid regurgitation: a proof-of-concept study.

Renal and liver congestion are associated with adverse outcomes in patients with tricuspid regurgitation (TR). Currently, there are no valid sonographic indicators of fluid status in this population. Intra-renal venous Doppler (IRVD) is a novel method for quantifying renal congestion but its interpretation can be challenging in severe TR due to altered haemodynamics. This study explores the potential of portal vein Doppler (PVD) as an alternative marker for decongestion during volume removal in patients with severe TR. Forty-two patients with severe TR undergoing decongestive therapy were prospectively enrolled. Inferior vena cava diameter, PVD, and IRVD were sequentially assessed during volume removal. Improvement criteria were portal vein pulsatility fraction (PVPF) < 70% and renal venous stasis index (RVSI) < 0.5 for partial improvement, and PVPF < 30% and RVSI < 0.2 for complete improvement. After volume removal, PVPF significantly improved from 130 ± 39% to 47 ± 44% (P < 0.001), while IRVD improved from 0.72 ± 0.08 to 0.54 ± 0.22 (P < 0.001). A higher proportion of patients displayed improvement in PVD compared to IRVD (partial: 38% vs. 29%, complete: 41% vs. 7%) (P < 0.001). Intra-renal venous Doppler only improved in patients with concomitant improvement in severe TR. Portal vein Doppler was the only predictor of achieving ≥5 L of negative fluid balance [area under the ROC curve (AUC) 0.83 P = 0.001]. This proof-of-concept study suggests that PVD is the only sonographic marker that can track volume removal in severe TR, offering a potential indicator for decongestion in this population. Further intervention trials are warranted to determine if PVD-guided decongestion improves patient outcomes in severe TR.

RENOVATION OF A TOWER-TYPE INDUSTRIAL BUILDING AS AN EXAMPLE OF THE WATER TOWER OF THE UKRAINIAN STATE UNIVERSITY OF SCIENCE AND TECHNOLOGIES

Purpose. Research and analysis of the main approaches to the renovation of tower-type industrial buildings, establishing a connection between the geometric space and the functional-spatial zoning of the premises created on their basis. Methodology. The study is devoted to one of the groups of neglected engineering structures, such as water towers. Such industrial facilities are already embedded in the infrastructure of the city, as a rule, they are embedded in dense urban development, which adds leverage for the preservation and renovation of such facilities. During the reconstruction of tower-type industrial buildings, there are problems of dismantling, removal and disposal of a large volume of structures and building materials. Study of national and international experience in renovation of tower-type industrial buildings. According to the requirements of DBN V.2.2-15:2019 "Buildings and structures. Residential buildings. Basic provisions" to the areas of the premises in a residential building, their placement in the space of the tower is analyzed in the process of designing the floors of the tower. Findings. The possibility of renovating the tower-type industrial structure of the water tower of the Ukrainian State University of Science and Technology into a residential building was considered. The architectural design of a 3-story residential building with the arrangement of separate entrances to the building with the help of an elevator and stairs and the distribution of spaces by floor according to functional purpose was completed. Originality. For the first time, the concept of a volume-planning solution for apartments in the limited space of a water tower was developed. This example gives impetus to the development of the reconstruction of tower-type buildings, their preservation as a historical and cultural heritage of Ukraine. Practical value. Water towers that are no longer used for their primary purpose can be reconstructed and can replenish the housing stock, acquire the significance of cultural and public centers in cities and settlements.

Inner Modulation Controlled Process for Suppression of Chatter Vibration in Double Inserts Turning

A novel cutting manner is presented to control regenerative chatter vibration in double inserts cutting, in which the forward and the backward inserts cut workpiece simultaneously with phase difference in the modulation of finished surface. In double inserts cutting, the forward insert is clamped above the backward insert. Both the inserts are positioned symmetrically with a height offset with respect to the workpiece rotation center. The forward insert mainly removes the material; while the backward insert cuts a part of the inner modulation to lose the regular excitation. The exciting force is also reduced with the cutting thickness of the forward insert after a workpiece revolution. Because the theoretical position offset of the inserts in the feed direction is small, the side cutting edges of inserts are aligned in the same position. The process parameters are determined by estimating the removal volume of the backward insert with the phase shift. The range of the cutting speed and the height offset are given by the frequency of the chatter vibration, which is nearly the same as the natural frequency of the workpiece in single degree of freedom. The proposed cutting manner is validated using comparison between the single insert and double inserts cuttings.

Investigating the Laser engraving on Polymethyl methacrylate sheets and process parameters optimization using GRA technique.

Abstract Polymethyl methacrylate (PMMA) is sound-resistant because it can lessen the transmission of outside sound waves. PMMA is widely used in many applications, such as automotive lighting, electronics and energy, health, sanitation, etc. Laser engraving for PMMA sheet panels with process parameters of good quality is a major problem in the process industry. There is a demand for surface roughness that is affected by the volume of material removal. Therefore, in this work, multi-value response optimization was performed on MRR and surface roughness during laser engraving of PMMA sheets using an optical fiber diode in a dry environment through gray relational analysis. Also, regression models are developed, and their responses are compared for their correlation. The GRA combined with the Taguchi method has proved efficient in the decision-making of multi-responses in a laser engraving environment.

Effect of rotation of abrasives on material removal in chemical mechanical polishing using a proposed three-body model: Molecular dynamics simulation

A three-body wear model, comprising a soft polyurethane pad, silica abrasive, and crystalline silicon substrate, was established to analyze the impact of abrasive rotation on material removal process during chemical mechanical polishing (CMP) through molecular dynamics simulation. The results revealed that abrasive rotation would reduce the local temperature in the contact area between the abrasive and the substrate due to the cooling effect, thereby enhancing the surface quality of the substrate and decreasing the material removal volume (MRV). However, another effect of abrasive rotation, termed the "hedgehog effect", resulting in an increase in MRV. Through the trade-off between the cooling effect and the porcupine effect, the abrasive rotation can not only improve surface quality but also increase the MRV.