scholarly journals Drill Hole Orientation: Its Role and Importance on the Compression Response of Pure Magnesium

2020 ◽  
Vol 10 (20) ◽  
pp. 7047
Author(s):  
Anirudh Venkatraman Krishnan ◽  
Penchal Matli ◽  
Gururaj Parande ◽  
Vyasaraj Manakari ◽  
Beng Chua ◽  
...  
Keyword(s):  
Structural Stability ◽  
Base Material ◽  
Drill Hole ◽  
Simulation Software ◽  
Compressive Yield Strength ◽  
Valuable Insight ◽  
Compression Tests ◽  
Drill Diameter ◽  
The Right ◽  
Through Hole

Drilling is used in creating cylindrical through-holes for various applications. While optimizing drilling parameters is widespread, the effect of a drilled through-hole on the structural stability of components is not fully documented. The base material, along with other parameters, such as drill diameter, drill location and its orientation affect structural stability. Since carrying out tests on different base materials can be time consuming, simulation software can instead be used to provide valuable information. However, the comparison between experiments and simulations gets difficult; hence, this study attempts to provide a basis for effective comparison by studying simulations and compression tests, comparing the two, and documenting the role of drill hole orientation on the compressive response of magnesium, a material with immense potential in light-weight components. Simulations and experiments were carried out on three through-hole orientations and were compared to the undrilled scenario. Results demonstrate significant differences in compression behaviour. While the compressive yield strength increased in all three drill orientations, ultimate strength and ductility was reduced in horizontal and angular drill hole orientations. These observations, therefore, provide valuable insight into choosing the right orientation for different applications.

scholarly journals Powder Metallurgical Synthesis of Biodegradable Mg-Hydroxyapatite Composites for Biomedical Applications

2015 ◽  
Vol 828-829 ◽  
pp. 165-171 ◽  
Author(s):  
César Augusto Stüpp ◽  
Chamini Lakshi Mendis ◽  
Marta Mohedano ◽  
Gábor Szakács ◽  
Felix Gensch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ball Milling ◽  
Base Material ◽  
Hot Extrusion ◽  
High Energy ◽  
Mg Alloys ◽  
Processing Route ◽  
Compressive Yield Strength ◽  
Compression Tests ◽  
Corrosion Properties

Biodegradable Mg alloys are a new class of temporary implant materials for musculo-skeletal surgery. Recent studies show that Mg-based alloys can be biocompatible and there is a high demand to design Mg alloys with adjustable corrosion rates and suitable mechanical properties. An approach to solving this challenge might be the use of Mg metal matrix composites (Mg-MMC). In this study, a Mg-MMC composed of ZK60 was investigated as the base material and hydroxyapatite (HA) particles were added for tailoring its properties. The composite was produced by high-energy ball milling followed by hot extrusion. This processing route was chosen, as HA in contact with molten Mg releases a toxic gas (phosphine – PH3). The HA particles were homogeneously distributed in the ZK60 matrix after ball milling and the composite was consolidated by hot extrusion. This work presents the influence of different amounts of HA on corrosion behavior and mechanical properties of the composite. Corrosion properties were evaluated by immersion and electrochemical measurements in physiological media at 37 °C. A slight improvement in the corrosion resistance was observed for Mg-MMC due to the presence of more stable corrosion products. Compression tests were used to measure the mechanical properties. Under compression, samples showed a slight increase in the compressive yield strength with the addition of HA, while the ultimate strength did not change significantly.

scholarly journals Right-sided Bochdalek hernia in an adult with hepatic malformation and intestinal malrotation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Naoki Enomoto ◽  
Kazuhiko Yamada ◽  
Daiki Kato ◽  
Shusuke Yagi ◽  
Hitomi Wake ◽  
...  
Keyword(s):  
Elective Surgery ◽  
Abdominal Cavity ◽  
Three Dimensional ◽  
Simulation Software ◽  
3D Simulation ◽  
Diaphragmatic Defect ◽  
Intestinal Malrotation ◽  
Intestinal Loop ◽  
Bochdalek Hernia ◽  
The Right

Abstract Background Bochdalek hernia is a common congenital diaphragmatic defect that usually manifests with cardiopulmonary insufficiency in neonates. It is very rare in adults, and symptomatic cases are mostly left-sided. Diaphragmatic defects generally warrant immediate surgical intervention to reduce the risk of incarceration or strangulation of the displaced viscera. Case presentation A 47-year-old woman presented with dyspnea on exertion. Computed tomography revealed that a large part of the intestinal loop with superior mesenteric vessels and the right kidney were displaced into the right thoracic cavity. Preoperative three-dimensional (3D) simulation software visualized detailed anatomy of displaced viscera and the precise location and size of the diaphragmatic defect. She underwent elective surgery after concomitant pulmonary hypertension was stabilized preoperatively. The laparotomic approach was adopted. Malformation of the liver and the presence of intestinal malrotation were confirmed during the operation. The distal part of the duodenum, jejunum, ileum, colon, and right kidney were reduced into the abdominal cavity consecutively. A large-sized oval defect was closed with monofilament polypropylene mesh. No complications occurred postoperatively. Conclusion Symptomatic right-sided Bochdalek hernia in adults is exceedingly rare and is frequently accompanied by various visceral anomalies. Accurate diagnosis and appropriate surgical repair are crucial to prevent possible incarceration or strangulation. The preoperative 3D simulation provided comprehensive information on anatomy and concomitant anomalies and helped surgeons plan the operation meticulously and perform procedures safely.

scholarly journals Effect of Build Orientation on the Microstructure, Mechanical and Corrosion Properties of a Biodegradable High Manganese Steel Processed by Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 944
Author(s):  
Martin Otto ◽  
Stefan Pilz ◽  
Annett Gebert ◽  
Uta Kühn ◽  
Julia Hufenbach
Keyword(s):  
Electron Backscatter Diffraction ◽  
Longitudinal Axis ◽  
Manganese Steel ◽  
Compressive Yield Strength ◽  
Powder Bed Fusion ◽  
Compression Tests ◽  
Laser Powder Bed Fusion ◽  
Corrosion Properties ◽  
Powder Bed ◽  
Manufacturing Technologies

In the last decade, additive manufacturing technologies like laser powder bed fusion (LPBF) have emerged strongly. However, the process characteristics involving layer-wise build-up of the part and the occurring high, directional thermal gradient result in significant changes of the microstructure and the related properties compared to traditionally fabricated materials. This study presents the influence of the build direction (BD) on the microstructure and resulting properties of a novel austenitic Fe‑30Mn‑1C‑0.02S alloy processed via LPBF. The fabricated samples display a {011} texture in BD which was detected by electron backscatter diffraction. Furthermore, isolated binding defects could be observed between the layers. Quasi-static tensile and compression tests displayed that the yield, ultimate tensile as well as the compressive yield strength are significantly higher for samples which were built with their longitudinal axis perpendicular to BD compared to their parallel counterparts. This was predominantly ascribed to the less severe effects of the sharp-edged binding defects loaded perpendicular to BD. Additionally, a change of the Young’s modulus in dependence of BD could be demonstrated, which is explained by the respective texture. Potentiodynamic polarization tests conducted in a simulated body fluid revealed only slight differences of the corrosion properties in dependence of the build design.

scholarly journals COMPARISON OF BASIC MAINTENANCE CONCEPTS USING WITNESS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5435-5440
Author(s):  
VLADIMIRA SCHINDLEROVA ◽  
◽  
IVANA SAJDLEROVA ◽  
Keyword(s):  
21St Century ◽  
Simulation Software ◽  
Predictive Maintenance ◽  
Maintenance Management ◽  
Practical Application ◽  
Manufactured Products ◽  
The Right ◽  
Positive Effect ◽  
Production Facilities

Maintenance is a complex, extensive and important issue in terms of its impact on the quality of manufactured products or services provided in all areas of industry. The importance of predictive maintenance for the industry in the 21st century is crucial. However, the right approach to maintenance management is often underestimated in many companies today, although it can have a very positive effect on the company’s efficiency. Using the example of a practical application, the paper includes a comparison of three main maintenance concepts – classical (reactive), planned, predictive through the simulation software Witness. Maintenance concepts are compared in terms of their ability to solve and eliminate failures that occur in production facilities during operation.

Rupture of the quadriceps tendon

2009 ◽  
Vol 22 (01) ◽  
pp. 74-80 ◽  
Author(s):  
T. Dembour ◽  
H. Gallois Bride ◽  
J. L. Chancrin ◽  
F. Arnault
Keyword(s):  
Tendon Rupture ◽  
Systemic Disease ◽  
Weight Bearing ◽  
Quadriceps Tendon ◽  
Drill Hole ◽  
Quadriceps Tendon Rupture ◽  
Loop Pattern ◽  
Traumatic Origin ◽  
One Year ◽  
The Right

SummaryA five-month-old, male, 16 kg, mixed breed dog was presented for an acute non-weight bearing lameness of the right hind limb. A subtotal avulsion of the quadriceps tendon at its patellar insertion was diagnosed through radiography and ultrasonography. Two nylon sutures secured with a stainless steel crimp were placed in a locking loop pattern in the quadriceps tendon and through a transverse 2.7 mm drill-hole in the patella. No external coaptation was used postoperatively. A full functional recovery was observed, and was followed for one year postoperatively. Quadriceps tendon rupture has not been described in the veterinary literature to our knowledge; in humans, quadriceps tendon rupture is a well known entity, often due to systemic disease resulting in weakening of the tendinous structures. In the case presented herein, the dog’s history, young age and location, without underlying biochemical abnormalities, led us to believe that the observed lesion was of traumatic origin. The surgical treatment performed was based on that performed in humans and also that which has been investigated experimentally in the dog.

Investigation of Drill Hole Quality of Multi-Layer PWBs for High Current Capacity

2007 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Kenichi Mori ◽  
Yuusuke Itagaki
Keyword(s):  
Copper Foil ◽  
Drill Hole ◽  
Foil Thickness ◽  
Electronic Systems ◽  
Hole Quality ◽  
Large Current ◽  
Drill Holes ◽  
Objective Variable ◽  
Chip Load ◽  
Through Hole

Recently, as a result of changes in the automotive industry, a large number of electronic systems have been installed in cars. The thickness of the copper foil used for printed wiring boards (PWBs) has tended to increase in response to the large current capacity required for such electronic equipment. Therefore, the nail head generated in the inner layer copper foil was examined with respect to the influence of the thickness of the copper foil on the through-hole quality. In the present study, the size of the nail head generated in the copper foil after drilling a through hole was used as the objective variable. The explaining variables included drill wear, frequency, feed rate, chip load, drill temperature, copper foil thickness, copper foil cutting distance, and number of drill holes. We investigated the relationships between these explaining variables and the objective variable and found that the copper foil cutting distance was a very important parameter in generating nail heads. In addition, we found that the chip load is important for controlling nail head generation.

scholarly journals Pathological and microbiological impact of a gentamicin-loaded biocomposite following limited or extensive debridement in a porcine model of osteomyelitis

2020 ◽  
Vol 9 (7) ◽  
pp. 394-401
Author(s):  
Sophie A. Blirup-Plum ◽  
Thomas Bjarnsholt ◽  
Henrik E. Jensen ◽  
Kasper N. Kragh ◽  
Bent Aalbæk ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Porcine Model ◽  
Drill Hole ◽  
Post Mortem ◽  
Tissue Samples ◽  
Group A ◽  
Extensive Debridement ◽  
Group B ◽  
The Right ◽  
Surrounding Bone

Aims CERAMENT|G is an absorbable gentamicin-loaded biocomposite used as an on-site vehicle of antimicrobials for the treatment of chronic osteomyelitis. The purpose of the present study was to investigate the sole effect of CERAMENT|G, i.e. without additional systemic antimicrobial therapy, in relation to a limited or extensive debridement of osteomyelitis lesions in a porcine model. Methods Osteomyelitis was induced in nine pigs by inoculation of 104 colony-forming units (CFUs) of Staphylococcus aureus into a drill hole in the right tibia. After one week, the pigs were allocated into three groups. Group A (n = 3) received no treatment during the study period (19 days). Groups B (n = 3) and C (n = 3) received limited or extensive debridement seven days postinoculation, respectively, followed by injection of CERAMENT|G into the bone voids. The pigs were euthanized ten (Group C) and 12 (Group B) days after the intervention. Results All animals presented confirmatory signs of bone infection post-mortem. The estimated amount of inflammation was substantially greater in Groups A and B compared to Group C. In both Groups B and C, peptide nucleic acid fluorescence in situ hybridization (PNA FISH) of CERAMENT|G and surrounding bone tissue revealed bacteria embedded in an opaque matrix, i.e. within biofilm. In addition, in Group C, the maximal measured post-mortem gentamicin concentrations in CERAMENT|G and surrounding bone tissue samples were 16.6 μg/ml and 6.2 μg/ml, respectively. Conclusion The present study demonstrates that CERAMENT|G cannot be used as a standalone alternative to extensive debridement or be used without the addition of systemic antimicrobials. Cite this article: Bone Joint Res 2020;9(7):394–401.

Simulation Study on Main Affect Factors to the Evacuation Corridor

2012 ◽  
Vol 170-173 ◽  
pp. 3533-3538 ◽  
Author(s):  
Yi Zhou Chen ◽  
Si Jing Cai ◽  
Yun Feng Deng
Keyword(s):  
Simulation Study ◽  
Emergency Evacuation ◽  
Simulation Software ◽  
Primary Factor ◽  
Pedestrian Evacuation ◽  
The Right ◽  
Efficiency And Reliability ◽  
Increase Efficiency

The primary goal of emergency evacuation for pedestrians is evacuating as many people as possible to safe areas in a shortest time when the accident occurred. And the primary factor of pedestrian evacuation is egress. According to the literature, we can know that the reasonable design of the evacuation corridor and the right guidance to pedestrians are very important, and analyzed main affect factors to the evacuation corridor, which affect of the evacuation speed for corridor at different pedestrian flows intensity, the width of evacuation corridor, setting canalization to corridor and the size of space of corridor peripheral. This paper use VISSIM simulation software to study on pedestrian flows evacuation. So the formulation for pedestrian evacuation program should consider a variety of elements for the design of the evacuation egress and corridors to increase efficiency and reliability for pedestrian evacuation.

scholarly journals Characterisation of Hybrid Metal Matrix Syntactic Foams

2015 ◽  
Vol 812 ◽  
pp. 219-225 ◽  
Author(s):  
Imre Norbert Orbulov ◽  
Kornél Májlinger
Keyword(s):  
Volume Fraction ◽  
Mechanical Energy ◽  
Matrix Material ◽  
Hollow Spheres ◽  
Base Material ◽  
Outer Diameter ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Pressure Infiltration ◽  
Geometrical Properties

High quality aluminium matrix syntactic foams (AMSFs) were produced by pressure infiltration. This method can ensure the maximal volume fraction of the reinforcing hollow spheres and very low amount of unwanted or matrix porosities. By this method hybrid MMSFs with mixed metal and ceramic hollow spheres were also produced. The matrix material was AlSi12 alloy and two different types – produced by Hollomet GmbH in Germany – of hollow spheres were used: Globomet (GM) and Globocer (GC). The geometrical properties of the hollow spheres were similar (average outer diameter), but their base material was pure iron and Al2O3+SiO2 in the case of GM and GC hollow spheres respectively. The volume fraction of the reinforcing hollow spheres were maintained at ~65 vol%, but the ratio of them was altered in 20% steps (100% GM + 0% GC, 80% GM + 20% GC...). The results of the compression tests showed, that the compressive strength, yield strength, plateau strength, structural stiffness and the absorbed mechanical energy values increased with higher ceramic hollow sphere reinforcement ratio. The fracture strains of the investigated MMSFs decreased with the higher GC ratio. Generally the strength values also increased with higher diameter to height (H/D) ratio from H/D=1 to H/D=1.5 and 2.

scholarly journals Oxygen transport and release of adenosine triphosphate in micro-channels and arterioles in the human microcirculation

2014 ◽  
Author(s):  
Terry Moschandreou
Keyword(s):  
Oxygen Transport ◽  
Rapid Change ◽  
Microfluidic Channel ◽  
Simulation Software ◽  
Time Dependent ◽  
Permeable Membrane ◽  
Micro Channels ◽  
Free Region ◽  
Channel Tube ◽  
The Right

The governing nonlinear equations for oxygen transport and ATP concentration in a microfluidic channel and tube are solved with the aid of Maple and COMSOL Multiphysics simulation software. Considering a cell-rich and cell free region with RBCs and blood plasma, we obtain results showing clearly that there is a significant decrease in oxygen tension in the vicinity of an oxygen permeable membrane placed midway on the upper channel/tube wall and to the right side of it in the downstream field. The purpose of the membrane is to cause a rapid change in oxygen saturation as RBC’s flow through channel/tube. To the right of the membrane downstream the greatest amount of ATP is released. Finally the corresponding time-dependent oxygen transport problem for plug flow in a channel, which has not been simulated in previous models in the literature, is analyzed and different starting times are shown for ATP release at different points in the channel. The FE modelling is very accurate: The time evolution problem is modelled and solved in it`s entirety with exact parameters used in the literature for blood flow and oxygen transport in the microcirculation. A comparison is made between the steady state and time dependent solutions in order to validate the results. The implications of the time dependent model for biological systems such as the human microcirculation requires exact information on release of energy as ATP is released from blood cells and the present work is important in providing this information.

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