Big Hole Research Articles

Production of activated carbon from coal with H3PO4 activation for adsorption of Fe(II) and Mn(II) in acid mine drainage

Acid Mine Drainage (AMD) contains Fe(II) and Mn(II) metals, which can cause environmental pollution. This research aimed to investigate the potency of activated carbon made from coal as an adsorbent in AMD treatment. The carbon was made of coal and activated with H3PO4 in a weight ratio of 40%, 800 °C for 120 minutes while supplying 1.5 L/min of nitrogen during the carbonization process. The result shows that BET surface area, total pore volume, and iodine number were 296.4 m2/g, 0.156 cc/g, and 1205 mg/g, respectively. The surface contained many fractures, channels, and big holes, as evidenced by the FT-IR and SEM investigations, and it also had acidic surface functional groups. The optimum contact time adsorption for AMD treatment was 30 minutes, and the first concentration of Fe(II) and Mn(II) metals affected the adsorption. The optimum removal of Fe(II) in AMD treatment was 95.27% at an initial concentration of 3.51 ppm, while the optimum removal of Mn(II) was 99.82% at an initial concentration of 5.71 ppm. This activated carbon has a considerable potency to be used as the adsorbent in AMD treatment to reduce Fe(II) and Mn(II) levels.

Research on a kind of positioning anti-eccentric fixture for measuring thin wall gear with special big inner hole

This paper mainly studies and designs the clamping tool which is installed in the measuring of big gears with big inner holes and thin walls. This paper analyzes the disadvantages of conventional clamping of large gears with special inner holes, and presents an example of the research and development of the Assembly of the mounting and positioning device of the special large inner hole gear based on the gear measuring instrument. At present, in the field of gear measurement, the measurement of large gears is always a technical problem. The technical ability of gear testing in our country is restricted by various factors. Most gear high-precision instruments and their accessories still depend on imports, which cannot be a good solution to the measurement of special gear installation and positioning problems from the economy and timeliness. Especially, large gears with large bores and thin walls face the problem of determining the position of the measuring device and the measured gears, that is, the measuring datum is difficult to determine [1]. This paper proposes how to use the existing gear measuring instrument to develop and use small accessories, so as to help the production enterprises and measuring institutions solve the problem of reference positioning in the actual production measurement process and determine the accuracy of special gear samples.

Two of a Kind: Comparing Big and Small Black Holes in Binaries with Gravitational Waves

When modeling the population of merging binary black holes, analyses have generally focused on characterizing the distribution of primary (i.e., more massive) black holes in the binary, while using simplistic prescriptions for the distribution of secondary masses. However, the secondary mass distribution and its relationship to the primary mass distribution provide a fundamental observational constraint on the formation history of coalescing binary black holes. If both black holes experience similar stellar evolutionary processes prior to collapse, as might be expected in dynamical formation channels, the primary and secondary mass distributions would show similar features. If they follow distinct evolutionary pathways (for example, due to binary interactions that break symmetry between the initially more massive and less massive stars), their mass distributions may differ. We present the first analysis of the binary black hole population that explicitly fits for the secondary mass distribution. We find that the data is consistent with a ∼30 M ⊙ peak existing only in the distribution of secondary rather than primary masses. This would have major implications for our understanding of the formation of these binaries. Alternatively, the data is consistent with the peak existing in both component mass distributions, a possibility not included in most previous studies. In either case, the peak is observed at 31.4−2.6+2.3M⊙ , which is shifted lower than the value obtained in previous analyses of the marginal primary mass distribution, placing this feature in further tension with expectations from a pulsational pair-instability supernova pileup.

Effect of temperature on growth, survival, and chronic stress responses of Arctic Grayling juveniles.

Arctic Grayling Thymallus arcticus are Holarctically distributed, with a single native population in the conterminous United States occurring in the Big Hole River, Montana, where water temperatures can fluctuate throughout the year from 8 to 18 °C. A gradual increase in mean water temperature has been reported in this river over the past 20 years due to riparian habitat changes and climate change effects. We hypothesized that exposing Arctic Grayling to higher temperatures would result in lower survival, decreased growth, and increased stress responses. Over a 144-day trial, Arctic Grayling juveniles were subjected to water temperatures ranging from 8-26 °C to measure the effects on growth, survival, gene expression and antioxidant enzyme activity. Fish growth increased with increasing water temperature up to 18 °C, beyond which survival was reduced. Fish did not survive at temperatures above 22 °C. In response to temperatures above 16 °C, a 3-fold and 1.5-fold increase in gene expression was observed for superoxide dismutase (SOD) and glutathione peroxidase (GPx), respectively, but no changes were seen in the ratio of Heat Shock Protein 70 (HSP70) and heat shock protein 90 (HSP90) expression. Enzyme activities of SOD and GPx also rose at temperatures above 16 °C, indicating heightened oxidative stress. Catalase (CAT) gene expression and enzyme activity decreased with rising temperatures, suggesting a preference for the GPx pathway, as GPx could also be providing help with lipid peroxidation. An increase of Thiobarbituric acid reactive substances (TBARS) was also recorded, which corresponded with rising temperatures. Our findings thus underscore the vulnerability of Arctic Grayling to minor changes in water temperature. Further increases in mean water temperature could significantly compromise survival of Arctic Grayling in the Big Hole River.

ROSES, the only RObotic System for any Endovascular Surgery, Including the Control of an Animated Catheter Characterized by the Presence of two Controlled Curvatures

The paper presents ROSES, its robotic components, the different devices, not necessarily sterile, and its disposables, suitable for any endovascular procedure, both actually performed and presently not assisted by any robotic system, and open in the future for new application yet to come, such as what will be allowed by the new animated catheter. In fact, this is due to the mechanical configuration of the robotic actuators based on a peculiar gear train which presents a big passage hole which allows both the passage of big catheters and even hemostasis valves, as well as full control of very small catheters and guide wires. The system measures forces opposed by the body showing their value both numerically and analogically without the need of any. special tool, measures length of penetration of each catheter and guide wires recording their value. Thus, it may become in future, connected to a work station that will register in real time also the fluoroscopic images, a kind of black box of endovascular surgeries, separating completely doctor and nurses from the patient, using also cameras and microphones to replace the physical contact with the patient.

Tube explosion during continuous supercritical water oxidation of sludge: An incident investigation

Supercritical water oxidation (SCWO) is well known as a promising end-of-pipe technology for treatment of hazardous wastes. Safety is undoubtedly the first concern as the SCWO should be operated under a harsh chemical and physical environment, including high temperature, high pressure, and high corrosive medium and plugging risk. This paper is the first report about a tube explosion incident that encountered during continuous SCWO treatment of industrial sludge. 3D imaging, Scanning Electron Microscope - Energy Dispersive Spectroscopy (SEM-EDS) and 3D finite element analysis are used to analyze the incident tube comprehensively. The results indicate that the incident tube was working at a hash corrosive environment of subcritical water and chloride, which leads to all of general, pitting and intergranular corrosions. Of which, the pitting is the most severe one that finally results to perforation. Then, leakage took place. Soon afterwards, the hard inorganic particle from sludge plugged the leaking pore for a second, but immediately split it as a big hole due to the local high pressure around the leaking pore. Finally, explosion occurred. Three lessons are drawn for the future safe design and operation of SCWO, i.e., selecting suitable pressure bearing material, checking regularly, and executing safety regulations.

Dark matter from hot big bang black holes

Dark matter from hot big bang black holes

Dual laser-assisted hatching: an effective technique to salvage low-grade cleavage-stage embryos and harvest day 7 blastocysts

To investigate whether repeating laser-assisted hatching (LAH) procedure on day 6 low-grade cleavage-stage embryos (LGCEs) helps blastulation. A total of 579 cycles with LGCEs from 2019 to 2022 was retrospectively reviewed. In 323 cycles, single LAH producing small holes (10 μm) was performed on LGCEs on day 4 (D4-LAH). In 256 cycles with persistent LGCEs despite D4-LAH, a repeat LAH procedure was performed on day 6 (Dual-LAH) with a bigger hole (30 μm). We compared day 7 blastocyst formation rate, usable blastocyst rate, and good grade blastocyst rate from these day 6 LGCEs between the two groups. Compared to the D4-LAH group, the Dual-LAH group had both higher day 7 blastocyst formation rate (9.4% vs. 3.0%, p < 0.001) and higher day 7 usable blastocyst rates (7.4% vs. 2.1%, p < 0.001). For persistent LGCEs despite single LAH, performing a repeat LAH on day 6 increased day 7 blastocyst formation rate.

Cumulative effect of Shearing parameters and Ramp angle on Hole surface quality in Ti6Al4V by Helical milling strategy

Hole creation is a common contour in drilling and milling. However, drilling big holes in Ti6Al4V is difficult. It is due to the thermally increased metallurgical behavior of Ti6Al4V, which mortifies drill bits and degrades hole quality. To solve this issue, the current research investigates Helical milling through Computer Aided Tool Path as a viable option for Hole production by functionally managing shearing parameters. This approach drives the process parameters helically at a certain Ramp angle to achieve improved surface quality in the Hole. The analysis of variance reveals that the Cutting Speed and Feed/tooth affect the Circularity of the Hole. Furthermore, Axial DOC and Ramp angle significantly impactHole surface texture. The cumulative impact of Cutting Speed at 60 m/min, Feed/tooth at 0.06 mm, and Axial Depth of Cut at 0.6 mm applied at a Ramp angle of 1.50 through theHelical milling tool path under Hybrid nano Flood lubrication catch the outstanding Hole Quality.

Prioritizing Colombian plant genetic resources for investment in research using indicators about the geographic origin, vulnerability status, economic benefits, and food security importance

Germplasm banks are the most significant repository for plant genetic resources for food and agriculture (PGRFA) worldwide. Despite their strategic importance, national germplasm banks of tropical megadiverse developing countries such as Colombia have extremely limited funds. Therefore, making strategic decisions about research investment is essential. Here, we designed a data-driven approach to build an index that sorts Colombian PGRFA into three groups: high, medium, or low priority, based on four pillars of information from open-access databases and aligned with the sustainable goals of no poverty and zero hunger: Geographic origin, vulnerability status, economic benefits, and food security importance. We analyzed 345 PGRFA using the index, separating them into two groups, 275 already conserved in the Colombian germplasm bank (BGVCOL group) and 70 not currently conserved in the BGVCOL (NCB group). We used fuzzy logic to classify each PGRFA by each pillar and integrate it to obtain a priority index. Missing data for native crops were frequent in the BGVCOL group. Therefore we adopted an imputation strategy to fill the gaps and calculated the uncertainty. After applying the index, PGRFA with higher priority were 24 (8.72%) from the BGVCOL (i.e., 15 potatoes, three tomatoes, two tree tomatoes, pineapple, cocoa, papaya, and yacon) and one from NCB (i.e., coffee). We concluded that this methodology successfully prioritized PGRFA in Colombia and shows the big holes of knowledge for future research and alternatives to improve this index. The versatility of this methodology could be helpful in other genebanks with budget limitations for research investment.

The Life and Legacy of Danijela Kulezic-Wilson

The Life and Legacy of Danijela Kulezic-Wilson

Development of panorama vision ring for thoracoscopy

Minimally invasive surgery (MIS) using a thoraco- or laparoscope is becoming a more common surgical technique. In MIS, a magnified view from a thoracoscope helps surgeons conduct precise operations. However, there is a risk of the visible area becoming narrow. To confirm that the operation field is safe, the surgeon will draw the thoracoscope back to check the marginal area of the target and insert it again many times during MIS. To reduce the surgeon's load, we aim to visualize the entire thoracic cavity using a newly developed device called "panorama vision ring" (PVR). The PVR is used instead of a wound retractor or a trocar. It is a ring-type socket with one big hole for the thoracoscope and four small holes for tiny cameras placed around the big hole. The views from the tiny cameras are fused into one wider view that visualizes the entire thoracic cavity. A surgeon can proceed with an operation by checking what exists outside of the thoracoscopic view. Also, she/he can check whether or not bleeding has occurred from the image of the entire cavity. We evaluated the view-expansion ability of the PVR by using a three-dimensional full-scale thoracic model. The experimental results showed that the entire thoracic cavity could be visible in a panoramic view generated by the PVR. We also demonstrated pulmonary lobectomy in virtual MIS using the PVR. Surgeons could perform a pulmonary lobectomy while checking the entire cavity. We developed the PVR, which uses tiny auxiliary cameras to create a panoramic view of the entire thoracic cavity during MIS. We aim to make MIS safer for patients and more comfortable for surgeons through the development of the PVR.

Greek history

I commence this review with a number of important works in Greek social history. As I commented in my last review for this journal, the study of labour is among the biggest holes in current research in Greek history. An important contribution towards filling this gap is the Cultural History of Work in Antiquity, edited by Ephraim Lytle. The volume gives an excellent overview of how work is represented and discussed in both literary and archaeological sources; at the same time, it situates work and workers within four important contexts: the structures of ancient economies and the level of trade and specialization determined demand in urban and rural labour; the changing form of workplaces determined the division of labour among workers; different forms of work developed highly divergent workplace cultures; finally, practices and organizations for the transmission of skills and knowledge were of critical importance. Work and workers are then placed within wider contexts: chapters explore the role of mobility in ancient labour markets, and how political communities and attitudes about different forms of work affected workers. Finally, work is profitably juxtaposed to leisure practices and ideas. Perhaps the strongest point of most chapters is their attention to regional diversity and historical change: the volume sets the groundwork for ultimately producing a dynamic narrative of the history of work in antiquity.

Design of Brush Plating Repair Device for Big Hole of Connecting Rod of Automobile

Brush plating technology has been applied to the surface repair and strengthening of parts and achieved remarkable benefits, so it can be used as a part remanufacturing method. This graduation project aims to design a brush plating repair device for the big end hole of an automobile connecting rod in the field of automobile technology application, including brush plating power supply, electroplating pen, plating solution, and brush plating auxiliary equipment, so as to realize the clamping and rotation of the workpiece, the clamping of plating pen and the axial and radial movement of plating pen relative to the workpiece. The three-dimensional models of parts and parts are established by modeling software and installed. The equipment can greatly improve the maintenance efficiency and product quality of vehicle connecting rods, obtain a safer production process, and is suitable for mass reproduction of vehicle connecting rods.

Flow-Control Plates to Manage Denil Fishways in Irrigation Diversions for Upstream Passage of Arctic Grayling

Abstract Small-stream irrigation diversions are key elements of many on-farm irrigation systems but can act as barriers to aquatic species. Denil fishways have been installed at irrigation diversion structures throughout the Big Hole River watershed in Montana to provide upstream passage for a population of Arctic Grayling Thymallus arcticus. When stream flows are low and irrigation demand is high, irrigators look for ways to maintain adequate diversion, but doing so may reduce the effectiveness of the fishways. In response, agencies and irrigators have proposed flow-control plates placed at the upstream end of fishways. We conducted laboratory-based fishway efficiency experiments with Arctic Grayling placed in an open-channel flume fitted with a Denil fishway and three flow plates. Of the total 200 fish that we used, the fishway entrance attracted 154 fish and we counted these fish as participants. We operated the fishway under varying flow conditions using three flow-control plate treatments and a control to investigate 1) the extent to which each treatment reduced flow compared to the control, and 2) the extent to which each treatment impacted passage success of Arctic Grayling relative to the control. We measured passage success as the ratio of the number of fish that fully ascended the fishway treatment to the number of participant fish attracted to the fishway treatment. One of the three plates, the Denil slot treatment, showed no evidence of reducing either flow or passage success. Another plate, the standard treatment, showed no evidence of reducing flow but moderate evidence of reducing passage success (P = 0.03). The only treatment to significantly reduce water flow rate was the narrowed Denil slot treatment and there was no evidence this treatment reduced passage in comparison to the control. Over all trials, water flow rate through the Denil fishway had a strong positive influence on fish passage success.

A big round hole in the elbow

A big round hole in the elbow

Sleeve Gastrectomy Associated with Antral Lesion Resection and Roux-en-Y Antrojejunal Reconstruction

Obesity has been growing worldwide, reaching epidemic proportions. Bariatric surgery is the most effective and durable treatment for severe obesity and related diseases. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are the most frequently performed bariatric operations, with long-term good results, in terms of weight loss and comorbidities control. Gastroesophageal Reflux Disease (GERD) is commonly associated with obesity. In general, it precludes the indication of sleeve gastrectomy, since this technique has a refluxogenic potential, as shown in many studies. In such cases, RYGB is considered the best surgery, reaching good weight loss and gastroesophageal reflux disease control. The drawback of this technique is that it leaves the remnant stomach, the duodenum, and the proximal part of the jejunum inaccessible. Besides, RYGB makes transoral endoscopic access to the biliary tree impossible. For all these reasons, this bariatric technique is not indicated in cases of gastric polyposis, gastric dysplasia, or strong family history of cancer, among others. We report a case of a morbidly obese patient with intense GERD, for whom a RYGB was precluded due to her strong family history of cancer, even knowing that it would be the best choice for reflux disease control. Instead, SG was chosen, even knowing it could worsen the gastroesophageal reflux disease. The patient signed an informed consent, after being fully enlightened about the risks. During the surgery, a small subserosal whitish lesion was detected, near the pylorus, on the anterior wall of the antrum. Thinking in a Gastrointestinal Stromal Tumor (GIST), it was resected, with a 2 cm safety margin, leaving a 4 to 5 cm hole on the gastric wall. The decision to maintain the proposed sleeve gastrectomy was made, to avoid leaving a remnant stomach, in a patient with such a strong family history of cancer. In the area of the resected lesion, an intraoperative decision was made not to just close the big gastric hole, being afraid of causing some anatomic or functional disturbance in gastric emptying. Instead, we decided to use the gastric opening to construct a Roux-en-Y antrotrojejunal anastomosis, with a 50 cm alimentary limb and a 200 cm biliopancreatic limb. Accordingly, it was performed a sleeve gastrectomy, associated with an antrojejunostomy in a Roux-en-Y fashion. The patient had an uneventful postoperative course. In the second year, she achieved normal weight and good nutritional status, without gastroesophageal reflux symptoms complaints. Seriography study shows that most of the contrast material passes through the antrojejunal anastomosis, instead of the pylorus, while the duodenum is endoscopically patent. This case report shows an unexpected surgical finding that led to a tactic of adding a Roux-en-Y gastric bypass in the antrum, associated with a sleeve gastrectomy, a strategy that may be adopted in cases of morbidly obese patients with important GERD, for whom gastrointestinal exclusions are contraindicated. To confirm this hypothesis, controlled studies are needed.

Damage detection in slab structures based on two-dimensional curvature mode shape method and Faster R-CNN

This paper proposes a novel method based on the two-dimensional (2D) curvature mode shape method, Convolutional Neural Networks (CNN), and Faster Region-based Convolutional Neural Networks (faster R-CNN) for detecting damage in slab structures. The 2D curvature mode shapes could be measured directly or calculated from the measured mode shapes using the central difference method. The damage indicator is defined as the absolute differences between the 2D curvature mode shapes of the damaged and intact slabs. The contour plot is chosen to convert the damage indicators into images. Four hundred damage scenarios are created using a Finite Element (FE) model of the slab. Images created from those damage scenarios are then used to train CNN and faster R-CNN. Four damage types are considered in this research, namely a single small hole, a single big hole, two small holes, and two large holes. After training, CNN can predict the damage types and faster R-CNN can predict the bounding boxes around the damaged areas. A test sample set is created to test the performance of the proposed method. The effect of noise in the mode shape data is considered. Results show that the classification accuracy for damage type is high. The overlap ratios between the predicted bounding boxes and the real damaged areas are more than 40% for 80% of tested scenarios. Furthermore, the low influence of noise on the predicted results is investigated. The proposed method is robust and has great potential for application to real structures.

Tensile Performances of Continuous Fiber Reinforced Thermoplastic Composites with holes processed by 3D Printing, Laser and Drilling

The continuous fiber-reinforced thermoplastic composites (called CFRTPCs) have been used in transportation, aerospace, sports and leisure products because of their great green recyclability and mechanical performances. This study evaluated the 3D printing process for the rapid manufacturing of CFRTPCs. The effect of laser and drilling processes, the size and shape of holes on mechanical performances of CFRTPCs were evaluated individually and mutually. The results proved that the small holes and low fiber content helped improve the strain at break while the big holes and the high fiber content helped improve the ultimate tensile strength and elastic modulus. The ultimate tensile strength and elastic modulus of specimens with square or big holes were higher than those of samples with circle or small holes. The ultimate tensile strength and elastic modulus of specimens with circle holes by laser were higher than those of samples with circle holes by drilling while the trend of strain at break was opposite. The micro morphology of the tensile breakage was observed and analysed to study the failure mechanism. This work makes an important contribution to the design of 3D printed CFRTPCs parts with holes.

Research and implementation of steel barrel cover rotation correction

Given the problems of low efficiency and poor accuracy of manual adjustment of offset position in screen printing of steel barrel cover, an automatic correction method based on machine vision is studied. The mode of upper-lower computers is adopted. For barrel cover with screw holes, Hough circle detection determines the number and position of screw holes and calculates the rotation direction and angle based on the big screw holes as the orientation datum. For barrel cover without screw holes, which is characterized by a steel seal, a minimum area rectangle is adopted to calculate the rotation direction and angle by collecting the location parameters of the width of the rectangle. The lower computer, PLC, controls the servo motor rotation and exchanges data through the Modbus TCP protocol. The results show that the method can adapt to the characteristics of the screw holes and the steel seal. The rotation angle is within (−180°, 180°). The angular error was ± 0.50°. The method meets the requirements of accuracy and stability.