Insertion Hole Research Articles

Investigation of a concrete railway sleeper failed by ice expansion

We investigated a conical crack formed near a fastening bolt of a concrete railway sleeper in a slab track system. The crack initiated from the bottom of the sleeper and penetrated the sleeper completely forming a conical shape. To study the reason for this and to examine the failure mechanism, we used a three dimensional finite element method and a series of experimental programs. The result of the numerical simulation was verified with the experimental data. From this study, we concluded that the conical crack was caused by the volume expansion of the freezing water leaking into the plastic insert of the fastener hole. The effect of location of the frozen insert holes, initial fastening force and compressive strength of concrete on the freezing force was also studied in this study.

A Manually Operated, Advance Off-Stylet Insertion Tool for Minimally Invasive Cochlear Implantation Surgery

The current technique for cochlear implantation (CI) surgery requires a mastoidectomy to gain access to the cochlea for electrode array insertion. It has been shown that microstereotactic frames can enable an image-guided, minimally invasive approach to CI surgery called percutaneous cochlear implantation (PCI) that uses a single drill hole for electrode array insertion, avoiding a more invasive mastoidectomy. Current clinical methods for electrode array insertion are not compatible with PCI surgery because they require a mastoidectomy to access the cochlea; thus, we have developed a manually operated electrode array insertion tool that can be deployed through a PCI drill hole. The tool can be adjusted using a preoperative CT scan for accurate execution of the advance off-stylet (AOS) insertion technique and requires less skill to operate than is currently required to implant electrode arrays. We performed three cadaver insertion experiments using the AOS technique and determined that all insertions were successful using CT and microdissection.

186 A Pre-Clinical Study to Determine the Time to Bone Sealing and Healing Following Intraosseous Vascular Access

186 A Pre-Clinical Study to Determine the Time to Bone Sealing and Healing Following Intraosseous Vascular Access

Poster 64: A New Haptic Drilling System With Feed Scaling

Poster 64: A New Haptic Drilling System With Feed Scaling

Immobilization and catheter guidance for breast brachytherapy

Brachytherapy is an important mode of breast cancer treatment; however, improvements in both treatment planning and delivery are needed. In order to meet these specific needs, integration of pre-operative imaging, supplemented by computerized surgical planning and mathematical optimization were used to develop and test an intra-operative immobilization and catheter guidance system. A custom template specific to each patient with optimally placed guide holes for catheter insertion was designed and fabricated. Creation of the template is based on a virtual reality reconstruction of the patient's anatomy from computed tomography imaging. The template fits on the patient's breast, immobilizing the soft tissue, and provides pre-planned catheter insertion holes for guidance to the tumor site. Agar-based phantom and target models were used for quantitative validation of the template by ascertaining the precision and accuracy of the templates. Tests were performed on agar-based tissue models using computed tomography imaging for template planning and validation. Planned catheter tracks were compared to post-insertion image data and distance measurements from target location were used to create an error measure. Initial results yielded an average error of 4.5mm. Once the workflow and template design were improved, an average error of 2.6mm was observed, bringing the error close to a clinically acceptable range. Use of a patient-specific template for breast brachytherapy is feasible and may improve the procedure accuracy and outcome.

A Computed Tomography-Based Localizer to Determine the Entry Site of the Ventricular End of a Parietal Ventriculoperitoneal Shunt

One of the major principles of shunt insertion into the brain involves choosing an entry site that avoids eloquent cortex. We describe a novel tool to accurately locate the burr hole for insertion of the ventricular end of a catheter during parietal ventriculoperitoneal shunt surgery. Computed tomography (CT)-based measurements in 2 dimensions were used to mark the entry point with the help of an indigenously designed Vellore burr hole localizer (VL). Patients underwent surgery with either the conventional method to localize the burr hole (Keen point; group A; n = 28) or the VL (group B; n = 28). An independent observer determined the accuracy of shunt placement on postoperative CT scans. The VL is designed with a fixed horizontal arm that can be aligned with the CT or magnetic resonance reference plane and a vertical arm with a flexible sliding horizontal arm that is attached to it with an adjustable screw. By manipulating the flexible arm along the contour of the skull and using the scale provided on both the vertical and horizontal arms, we can mark the burr hole site for placement of a parietal ventriculoperitoneal shunt. Overall accuracy in group A was 32.1%, whereas in group B, an accuracy of 82.1% could be achieved (P < .01). Placement of a burr hole guided by the VL increases the accuracy of the desired entry point of the ventricular catheter.

Performance improvement of blue phosphorescent organic light-emitting diodes by using hole–buffer structure

The characteristics of blue phosphorescent organic light-emitting diodes (PHOLEDs) with hole–buffer structure were investigated by inserting a hole transport-type host (TCTA) between the hole transport layer (HTL, TAPC) and emitting layer (EML, FIrpic:26DCzPPy). The hole transport-type host has lower hole mobility than the HTL material, which could effectively control the hole injection current from the HTL into the EML. Moreover, the hole injection barrier from HTL to EML can be reduced due to the suitable HOMO level of the insertion hole buffer layer, which results in the improvement of driving voltage. Furthermore, the power efficiency was improved by controlling the hole injection current through buffer layer thickness optimization. From the experimental results, an optimal blue PHOLED structure was established: ITO/TAPC(20 nm)/TCTA(25 nm)/FIrpic:26DCzPPy(20 nm)/3TPYMB(40 nm)/LiF(0.5 nm)/Al(200 nm). At luminance of 1000 cd/m 2, the driving voltage decreased from 6.3 to 5.1 V and power efficiency enhanced from 6.7 to 13.5 lm/W could be observed.

Analysis of the Mechanical Properties of Locking Plates with and Without Screw Hole Inserts

The purpose of this study was to determine if the use of screw hole inserts in empty locking screw holes improves the strength and failure characteristics of locking plates. Twenty 5-hole 1/3 tubular locking plates (Synthes, Paoli, Pennsylvania) were mounted on an oak dowel with a 1-cm gap simulating a fracture with comminution and bone loss. Ten of the 1/3 tubular plates had a screw hole insert placed in the center hole (centered over the simulated fracture), while 10 of the 1/3 tubular plates remained empty in the center hole. The plate-dowel constructs were placed in an Instron 8800 Material Testing Machine and subjected to a series of loading conditions, replicating physiologic loading. The torsional and axial stiffness of each plate-dowel construct was calculated. All plates were then loaded to failure. No significant differences were found in the mechanical properties of the 2 plate constructs. Both the filled screw-hole plate constructs and unfilled screw hole plate constructs demonstrated the same torsional and axial stiffness, before and after being subjected to a combined cyclic and axial torsional load. Additionally, there was no significant difference in ultimate compressive strength or load to failure. Locking plate technology is a relatively new innovation in orthopedic fracture fixation. The evolution of new and varied applications and implants continues. Persistent, fundamental questions exist concerning the basic locking plate design. This study demonstrates that the addition of screw hole inserts does not significantly change the stiffness, torsional strength, or axial loading strength of 1/3 tubular locking plates.

A Technological Study on Friction Stir Blind Rivet Jointing of AZ31B Magnesium Alloys and High-Strength DP600 Steel

Friction stir blind riveting (FSBR) is a new joining process which eliminates the need to predrill a hole for rivet insertion. Lap joint friction stir blind riveting the plates made of high strength steel DP600 (1 mm) and magnesium alloys AZ31B(3 mm) with different technological parameters was carried out. This study experimented with the strength and the morphology of the joint with different rotation speed and feet rates of the spindle rivet, and which material on bottom or top. The main results obtained are as follows: FSBR’s process of steel and magnesium alloy plate was quickly and successfully achieved. The maximum shear strength of the joint reached about 6.3KN and the fracture path was along the shank of rivet. When Mg plate is on top of the other, the spindle speed is 2,200rpm, and along with the increase of the feed rates, the gap of plates is decreased, the strength of joint is increased. When steel plate is on top layer, the spindle speed at 2,200rpm, the rivet can then plug into the plates with a feed rate at least 600mm/min, and the joint shear strength will become higher.

Functional Anatomy of Human Scalene Musculature: Rotation of the Cervical Spine

Objectives Actions of the scalene muscles include flexion and lateral flexion of the cervical spine and elevation of the first and second ribs. The cervical rotational qualities of the scalene muscles remain unclear. Textbooks and recent studies report contradictory findings with respect to the cervical rotational properties of the scalene muscles. The present study was designed to take a mechanical approach to determining whether the scalene muscles produce rotation of the cervical spine. Methods The scalene muscles were isolated, removed, and replaced by a durable suture material. The suture material was attached at the origin and then passed through a hole on the corresponding rib near the central point of the insertion. The suture material was pulled down through the corresponding costal insertion hole to simulate contraction of each muscle. Results The simulated anterior, middle, and posterior scalene muscles, working independently and jointly, produced ipsilateral rotation of the cervical spine. The upper cervical spine rotated in the ipsilateral direction in response to the simulated muscle contraction. Findings were similar for the lower cervical spine with the exception of 2 specimens, which rotated contralaterally in response to the simulation. Conclusion Experimental models of the scalene muscles are capable of producing ipsilateral rotation of the cervical spine. The findings of this study support the accepted main actions of the scalene muscles. The clinical applications for understanding the cervical rotational properties of the scalene muscles include the diagnosis, management, and treatment of cervical pain conditions as well as thoracic outlet syndrome.

Hydrogen sulfide protects against vascular remodeling from endothelial damage

Remodeling by its very nature implied synthesis and degradation of extracellular matrix (ECM) proteins. Although oxidative stress, matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) have been implicated in vascular remodeling, the differential role of MMPs versus TIMPs and oxidative stress in vascular remodeling was unclear. TIMP-3 induced vascular cell apoptosis, therefore, we hypothesized that during vascular injury TIMP-3, MMP-9 and -12 (elastin-degrading MMP) were increased, whereas MMP-2 (constitutive MMP) and TIMP-4 (cardioprotective TIMP) decreased. Because of the potent anti-oxidant, vasorelaxing, anti-hypertensive agent, hydrogen sulfide (H2S) was used to mitigate the vascular remodeling due to the differential expression of MMP and TIMP. Carotid artery injury was created by inserting a PE-10 catheter and rotating several times before pulling out. The insertion hole was sealed. Mice were grouped: wild type (WT), wild-type damaged artery (WTD), WT+NaHS (sodium hydrogen sulfide, precursor of H2S) treatment (30 µmol/L in drinking water/6 weeks) and WTD+NaHS treatment. Carotid arteries were analyzed for oxidative stress and remodeling, by measuring super oxide dismutase-1 (SOD1), p47 (NADPH oxidase subunit), nitrotyrosine, MMPs and TIMPs by in situ immunolabeling and by Western blot analyses. The results suggested robust increase in p47, nitrotyrosine, MMP-9, MMP-12, TIMP-3 and decrease in SOD1 and MMP-2 levels in the injured arteries. The treatment with H2S ameliorated these effects. We concluded that p47, TIMP-3, MMP-9 and -12 were increased where as SOD-1, MMP-2 and TIMP-4 were decreased in the injured arteries. The treatment with H2S mitigated the vascular remodeling by normalizing the levels of redox stress, MMPs and TIMPs.

The effect of new crown reamer at making insertion hole of Gamma 3 nail in femoral trochanteric fractures

The effect of new crown reamer at making insertion hole of Gamma 3 nail in femoral trochanteric fractures

A New One-Sided Joining Process for Aluminum Alloys: Friction Stir Blind Riveting

Friction stir blind riveting is a new joining process for one-sided joining (compared with the two-sided access required for, for example, self-piercing riveting) of aluminum alloys, which eliminates the need to predrill a hole for rivet insertion. A blind rivet rotating at high speed is brought into contact with the workpieces, thereby generating frictional heat between the rivet and the workpiece, which softens the workpiece material and enables the rivet to be driven into the workpieces under reduced force. Once fully inserted, the blind rivet is upset using the internal mandrel (as in a conventional blind riveting process) to fasten the workpieces together. Our study showed that friction stir blind riveting process can be carried out over a wide range of operating parameters. The resulting joints show consistent strength under tensile load with minimal influence of changes in operating parameters. The robustness of the process against variations in operating conditions shows that the process can be carried out without high-end equipment and without requiring precise initial setup. It also suggests that the process is feasible for rapid joint fabrication in volume production. Further study revealed superior static and fatigue strength from the friction stir blind riveting process, when compared with conventional spot welding, which suggests potential for reduction in the number of joints required in a structure.

Mandibular fractures associated with endosteal implants

The purpose of this study is to report four cases of mandibular fractures associated with endosteal implants and to discuss prevention and treatment of these types of fractures. To evaluate whether the patient's anatomy allows insertion of implants, radiological exams that demonstrate the height and the labial-lingual width are needed. To reduce the potential fracture problem, the mandible can be restrengthened with bone grafting techniques. The treatment of a fracture in an atrophic mandible is always a challenge because of the diminished central blood supply, the depressed vitality of the bone, and the dependence on the periosteal blood supply. The basic principles in fracture treatment are reduction and immobilization of the fractured site for restoration of form and function. If implants are placed in severe atrophic mandible, iatrogenic fracture of the mandible may occur during or after implant surgery because implant placement weakens the already-compromised mandible. A few millimeters of cortical bone should remain on both the labial and the lingual sites after the hole for insertion of an implant has been drilled. A 3-D surgical planning should be recommended at least in severe atrophic mandibles in order to prevent a severe reduction of bone tissue.

An experimental investigation on monitoring of crater wear in turning using ultrasonic technique

Tool life prediction and tool change strategies are now based on most conservative estimates of tool life from past tool wear data. Hence usually tools are underutilized. In an unmanned factory, this has the effect of increased frequency of the tool changes and therefore increased cost. An ultrasound online monitoring of crater wear of the uncoated carbide insert during the turning operation is presented. The method relies on inducing ultrasound waves in the tool, which are reflected by side flank surface. The amount of reflected energy is correlated with crater wear depth. Various ultrasonic parameters are considered for defining the crater wear and individual contribution of each parameter is analyzed. The ultrasonic parameters, amplitude, pulse width and root mean square (RMS) of the signal are used to quantify the crater depth and width. The power spectrum analysis of received signals shows the importance of frequency components in defining the tool wear. In the presented work, the normalizing of signals are carried out by insert hole, which is provided for clamping. This signal is not influenced by the wear but affected by other factors like tool material variation, improper couplant, temperature, etc. The response of the wear signal is normalized to the response of hole signal by mathematical division. A new approach adaptive neuro-fuzzy inference system (ANFIS) for monitoring of crater in carbide insert is presented. This improves the system accuracy and eliminates the limitation in statistical modeling that was presented in previous studies.

Athermal Elastomeric Lens Mount for Space Optics

We investigated the optimum adhesive thickness for athermalizing an elastomeric lens mount in our space optics application. Theoretical results were compared with finite element solutions using two different models; discrete circular pads and discrete circular pads with columns filling the insertion holes reflecting the reality. A noticeable difference between their optimal thicknesses was observed, and physical interpretation revealed the uncertainty of prevailing athermal equations. A pilot sample was made to check our results and thermo-optical stress was assessed using an interferometer after isothermal load. This study presented insight into preliminary design guidance in elastomeric lens mounting.

In vitro comparison of cortical bone temperature generation between traditional sequential drilling and a newly designed step drill in the equine third metacarpal bone

To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the mid diaphysis of each bone in lateral to medial direction, and drilling forces of 60, 80 and 120 N were used (15 holes in each group). Time from start to finish was measured and cortical thickness was recorded for each hole. The maximum heat generation (mean [95% CI]) with step drilling and sequential drilling was not significantly different at 60 N and 120 N of drilling force. However, at 80 N of drilling force, the 2.13 degrees C difference between the two drilling techniques was significant. The time to finish (seconds) was significantly shorter for the holes created by step drilling (35.1 [32.06 - 37.59]) than by sequential drilling (145.8 [138.52 - 151.67]) (P < 0.001). Based on our results, we concluded that the step drill is a viable alternative to traditional sequential drilling of equine third metacarpal bone because it did not result in excessive heat generation that can result in bone necrosis.

Wind shield and microphone

A pop reduction filter can be properly replaced with a simple operation according to the use of a microphone. A wind shield including a shield body 20 made of an open-cell foam with a microphone insertion hole 30 , the wind shield being directly put on a microphone M through the microphone insertion hole 30 , the wind shield including a disk-like pop filter 40 detachably housed in the microphone insertion hole 30 so as to be orthogonal to the 0-degree direction sound pickup axis of the microphone M, the pop filter 40 being made of an open-cell foam different in foam density from the open-cell foam of the shield body 20.

Estudo da influência do diâmetro do orifício piloto na resistência ao arrancamento do parafuso pedicular

A influência do diâmetro do orifício piloto em relação ao diâmetro interno do parafuso na resistência ao arrancamento do parafuso pedicular foi o objetivo do estudo. Foram utilizados parafusos de 5, 6 e 7 mm do sistema USS de fixação vertebral, os quais foram inseridos nos corpos de prova de madeira, poliuretana e osso. O orifício piloto para a inserção do parafuso foi realizado com brocas de diâmetro inferior, igual e superior ao diâmetro interno do parafuso. Ensaios mecânicos de arrancamento foram realizados em máquina universal de teste. Nos corpos de prova de madeira, poliuretana e osso a realização do orifício piloto com brocas de diâmetro maior que o diâmetro interno do parafuso produziu diminuição da força máxima de arrancamento dos implantes nos ensaios de arrancamento, tendo sido observada diferença estatística. O diâmetro da perfuração do orifício piloto em relação ao diâmetro interno do parafuso exerce influência na resistência ao arrancamento do implante, tendo sido observado aumento da resistência ao arrancamento com a utilização de brocas de diâmetro menor que o diâmetro interno e redução da resistência ao arrancamento com a utilização de brocas com diâmetro maior que o diâmetro interno do parafuso.

Practical expression for frequency deviation due to insertion hole in cylindrical cavity

One of the most widely used techniques for dielectric material characterisation is the partially filled circular cavity. To make these measurements the dielectric material is introduced into the cavity through a circular hole whose effects in the resonant frequency are traditionally neglected. A very simple expression is introduced to model this frequency deviation that improves the classical one. It takes into account the saturation effect that appears when materials with high permittivities are measured. The expression is obtained using circuital analysis and monomode approximation.