Metallic Connector Research Articles

An unusual cause of oxygen failure in the anesthesia machine.

Dear Editor, A critical incident is being reported wherein a foreign body was detected in the oxygen pipeline inlet at the back of anesthesia workstation. The potentially catastrophic incident occurred during routine pre-use checkup of anesthesia workstation when there was no flow of oxygen on opening the flow control valve while pressure gauge on the pressure regulator of D-type oxygen cylinder was showing full pressure. The pressure gauge on the anesthesia machine was also showing no pressure. The oxygen cylinder and pressure regulator were changed but still there was no oxygen flow. It was then thought to change the connecting hose between cylinder and pipeline inlet at the machine end. As the NIST (non-interchangeable screw thread) connector was loosened from the machine end, an interesting finding was noticed, there was sudden movement of bobbin and oxygen flow started but soon the flow again ceased and the bobbin came back to the same position. Then again on opening the cylinder but keeping the connector at pipeline inlet slightly loosened led to the flow of oxygen and pressure gauge on the workstation also started showing pressure reading. Noticing this finding that loosening the NIST connector of the hose slightly from the pipeline inlet led to oxygen flow in the workstation led us to suspect a foreign body in the oxygen pipeline inlet of workstation. Subsequent careful search in the oxygen inlet led us to find a small black ring which was taken out with an 18 g needle as it was at the distal end of the inlet[Figure 1]. It was a small round rubber ring with a hole in the centre. Initially it was suspected it to be washer of the Bodock seal but closer inspection revealed it to be of different size.Figure 1: Foreign body in the oxygen inlet at the back of anesthesia machineNow the reason for absence of flow on tightening the connector was understood, probably because on tightening the rubber ring became flat and occluded the oxygen entry port of the inlet causing complete cessation of the oxygen flow. When the connector was slightly loosened, the central opening in the ring came back to its normal position thus allowing oxygen flow. The mechanism of entry of the foreign body at that unusual location could not be figured out since the same anesthesia machine has been in use for 4 years. The engineer of the manufacturer, Datex Ohmeda, was contacted and his viewpoint was that it could be a deliberate attempt by theatre personnel; however this could not be confirmed. The other possible explanation could be wear and tear of the ring that caused cessation of oxygen flow on being pressed tightly by metallic NIST connector[Figure 2].Figure 2: Worn out foreign body and NIST connectorThough there are many human errors and equipment malfunctions reported leading to oxygen supply failure[1], but such a presentation of a foreign body at the pipeline inlet has not been reported earlier. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

An All-Textile Dual-Band Antenna for BLE and LoRa Wireless Communications

In this paper, a dual-band conductive textile-based wearable antenna operating at LoRa-868 MHz and BLE-2.4 GHz is presented. The proposed antenna is intended for accurate geolocation, tracking and communication applications in the military, industrial and telemedicine industries. The low-profile patch antenna is suitable for integrating into clothing. It is composed of three textile layers: top and bottom silver-ink-printed polystyrene fabrics, and a neoprene substrate. To utilize the flexible and restorable properties of these textile materials, the proposed antenna is directly fed by a flexible cable using an aperture-coupled feeding technique. This method not only eliminates the use of the conventional, bulky, and metallic SMA connector but also introduces a secondary resonance at 2.4 GHz, enabling the dual-band property. Using a thin coaxial cable fixed on the aperture slot for proximity coupling, a compact antenna size of 150 mm2 is obtained that can easily be attached and detached on existing cloths. The proposed structure has been fabricated and measured in an anechoic chamber to verify the performance. Measured gain of 3.28 dBi and 3.25 dBi was realized for LoRa and BLE at an antenna size of 0.61 λg × 0.61 λg × 0.012 λg (where λg is guided wavelength at 868 MHz) with a front-to-back ratio (FBR) of greater than 10 dBi.

Enhancement of adhesion between the polymeric liner and the metallic connector of high-pressure hydrogen storage tank

The importance of manufacturing of hydrogen fuel tanks due to the application of hydrogen fuels in clean and recyclable energy is one of the most important issues of substituting the petroleum fuels. They consist of two main parts: Plastic liner, as a barrier escape of hydrogen and Carbon Fiber Reinforced Polymer (CFRP) layer to strengthen tanks. The liner plastic could be manufactured by rotational molding or blow molding. In rotational molding, the metallic boss embedded into the mold directly and stick on the polymer before wrapping step. However, in blow molding, the metallic boss is welded to liner polymer. By comparing these two methods, rotational molding demonstrates better feedback because of its capability in assembling boss and liner part, and also manufacturing the piece simultaneously, without the defect arising from welding. Moreover, improvement in the adhesion capacity of polymer to metal could be obtained by effective surface treatments. Therefore, good knowledge of adhesion concept could be useful in these regards. In this work, the possible treatments on Aluminum (metal) and medium density polyethylene (liner) which could be applied in rotational molding is proposed and the adhesion behavior of them has been compared. These surface treatments are anodizing, flaming, sandblasting with different average size of sand particles, and coating with polyethylene grafted (PEG) (CEA patent n°FR3035173). Despite of the mechanical test results, it was found that the sandblasting treatment (with higher roughness value) combined with PEG coating performed higher adhesion at the interface of metal/polymer in compare with other possible methods in rotational molding. Microstructures of these different surface treatments confirmed the obtained mechanical results.

Endoscopic Lap-Band Removal at a Community Hospital: Experience and Lessons Learned

Laparoscopic gastric bands are one of several surgical modalities used for morbid obesity. While occurring at a low rate, a severe complication is intragastric erosion. Endoscopic Lap-Band removal has been shown to be an option to remove an eroded band. Here we demonstrate that the principles of endoscopic band removal can be used successfully in the community hospital setting, as well as describe our experience with the procedure. A 43-year-old female with an adjustable laparoscopic gastric band placed in 2010 presented with 3-4 months of symptoms consistent with an overly taught lap band. As an outpatient she was diagnosed with an eroded gastric band, which was shown to be about 60-70% inside the stomach lumen on initial endoscopy. The Lap-Band removal took place in the OR where both gastroenterology and surgery teams were present. First the surgical team identified and removed the Lap-Band tubing and metallic connector through a port. Then the GI team went in endoscopically, noting that the band was roughly 75% eroded into the stomach. A standard 0.035 wire was introduced and passed around the band. Both ends were then threaded through a lithotripter, which was tightened until the wire successfully passed through, transecting the band. Using a snare, the band was pulled fully into the stomach, and then the removal phase began. Difficulty was encountered while extracting the band through the upper esophageal sphincter, as it appeared to become caught. Using a stiff snare, gentle traction, and neck manipulation, along with briefly deflating the balloon cuff, the band was removed and came out intact. The patient tolerated the procedure, and did well post-op. Utilizing a multidisciplinary approach, an eroded Lap-Band was successfully removed endoscopically. We did encounter difficulty removing the band at the level of the upper esophageal sphincter. This was likely a result of the buckle of the band getting hung up. Manipulation was difficult, as we did not want to cause a potential tear by pulling the sharp edge of the cut band across the sphincter. Our difficulties did teach us some lessons. We would recommend cutting the band into two or more pieces to facilitate its removal and reduce the risk of esophageal trauma. Alternatively, using an Overtube is another option. This case highlights that endoscopic Lap-Band removal is a safe and effective procedure for removing an eroded band, and that such a procedure is able to be conducted at a community hospital.2161_A Figure 1. Initial endoscopic view of the eroded gastric Lap-Band.2161_B Figure 2. Endoscopic view of the lithotripsy wire passing around the eroded gastric Lap-Band.2161_C Figure 3. View of the removed, intact Lap-Band following endoscopic removal.

Experimental study of RC beams strengthened for bending by reinforced grout layer and connectors

Abstract This work is based on an experimental investigation of reinforced concrete beams strengthened to flexure for wrapping applying a type of metallic connector in the bond substrate/groute. The experimental program consisted of 5 beams used for reference (without strengthening), 5 beams reinforced with surface brushed texture substrate and 5 beams with metal connectors bonded to the substrate. The beams were submitted to four-point load bending test. Initially with a partial loading, executed the strengthening and were finally tested until the break. The strengthening was made up by the increase by graute, on the sides and bottom of the beam and reinforcing. The applied force, the displacement, deformations in steel and in concrete were measured. The reference beams failure by flexing with the calculated charges. The bending strengthening proved efficient, increasing the bearing capacity in 44% and the failure was by shear in the stretch without strengthening. Beams with connectors the increase was higher.

Transcutaneous spinal direct current stimulation of the lumbar and sacral spinal cord: a modelling study

Objective. Our aim was to perform a computational study of the electric field (E-field) generated by transcutaneous spinal direct current stimulation (tsDCS) applied over the thoracic, lumbar and sacral spinal cord, in order to assess possible neuromodulatory effects on spinal cord circuitry related with lower limb functions. Approach. A realistic volume conductor model of the human body consisting of 14 tissues was obtained from available databases. Rubber pad electrodes with a metallic connector and a conductive gel layer were modelled. The finite element (FE) method was used to calculate the E-field when a current of 2.5 mA was passed between two electrodes. The main characteristics of the E-field distributions in the spinal grey matter (spinal-GM) and spinal white matter (spinal-WM) were compared for seven montages, with the anode placed either over T10, T8 or L2 spinous processes (s.p.), and the cathode placed over right deltoid (rD), umbilicus (U) and right iliac crest (rIC) areas or T8 s.p. Anisotropic conductivity of spinal-WM and of a group of dorsal muscles near the vertebral column was considered. Main results. The average E-field magnitude was predicted to be above 0.15 V m−1 in spinal cord regions located between the electrodes. L2-T8 and T8-rIC montages resulted in the highest E-field magnitudes in lumbar and sacral spinal segments (>0.30 V m−1). E-field longitudinal component is 3 to 6 times higher than the ventral-dorsal and right-left components in both the spinal-GM and WM. Anatomical features such as CSF narrowing due to vertebrae bony edges or disks intrusions in the spinal canal correlate with local maxima positions. Significance. Computational modelling studies can provide detailed information regarding the electric field in the spinal cord during tsDCS. They are important to guide the design of clinical tsDCS protocols that optimize stimulation of application-specific spinal targets.

Study on Further Modification of Non-Contact Capacitance Type-Level Transducer for a Conducting Liquid

A non-contact capacitance type liquid-level transducer for a conducting liquid consists of a short circuited non-inductive coil wound on a uniform cylinder made of insulating material, such as glass, PVC, nylon, and teflon. The cylinder is connected with a storage tank through a metallic connector and the capacitance between upper short circuited end of the coil and metallic connector varies linearly with liquid level measured from datum level. The capacitance at datum level depends on atmospheric condition and the fringe effect of other conductors. So, the transducers require frequent recalibration depending on atmospheric and environmental conditions. In the present paper, this non-contact capacitive sensor has been further modified in order to minimize this defect of non-contact capacitive sensor. Furthermore, all the conventional capacitance type-level sensors are associated with a perpendicular plate capacitance between liquid and electrode, which varies with the length of the electrode. In this paper, the effect of this perpendicular capacitor on liquid level measured has been studied and its effect is minimized. The proposed modified transducer has been designed and developed and its theory of operation has been derived. The performance of the developed transducer has been experimentally studied and the experimental results are reported in the paper. A good linear performance characteristic of the transducer with very minimum parasitic capacitance effect has been observed.

Cyclic Behavior of Timber Column Concealed Base Joint

This paper presents experimental and numerical tests on a recently developed timber column concealed base joint. This joint was designed to replace the wood-wood connection found in the post-and-beam structure of Hanok, the traditional Korean timber house. The use of metallic connectors provides an increased ductility and energy dissipation for a better performance under reversed loading, especially seismic. In this study, we investigate the performance of the joint under pseudo-static reversed cyclic moment loading through the study of its ductility and energy dissipation. We first perform experimental tests. Results show that the failure occurs in the metallic connector itself because of stress concentrations, while no brittle fracture of wood occur. Subsequent numerical simulations using a refined finite element model confirm these conclusions. Then, using a practical modification of the joint configuration with limited visual impact, we improve the ductility and energy dissipation of the joint while retaining a same level of rotational strength as the originally designed configuration. We conclude that the joint has a satisfying behavior under reversed moment loading for use in earthquake resistant timber structure in low to moderate seismicity areas like Korea.

Point fixings in annealed and tempered glass structures: Modeling and optimization of bolted connections

In the design of high load bearing elements made of tempered flat glass, connections cannot be avoided when large spans or high stiffness beams are considered. This paper investigates bolted connections in glass structures; the main objective is to determine the optimal joint. This work is performed through the determination of stress states due to both thermal tempering and in-plane loading. The modeling of the thermal tempering is performed with the FE software Abaqus and additional user subroutines. Experiments on industrial tempering line with specific set-up allow the determination of the air flow in the hole and then of the forced convection coefficients. The radiative heat transfer is also modeled numerically and the semi-transparency of glass in the near infrared is considered. In order to calculate residual stresses, the visco-elasticity of glass and the structural relaxation phenomena are taken into account. The computed stresses are checked against photo-elastic measurements. As various holes are considered, this study allows to determine the hole geometry for which the tempering process is the most effective. For the study of the consequences of in-plane loading, a large experimental campaign has been performed. The studied connection is derived from countersunk supports. The influences of different parameters as the hole geometry, the nature of the washer between glass and metallic connector as well as the glass-washer material friction coefficient were investigated. The modeling of these tests is performed with the FE software Abaqus. This modeling takes into account the ductility of the materials, the friction and the clearances between the parts. This modeling is validated thanks to failure stress measurements. The combination of modeling and experiments leads to identify optimal connection.

Welding-through doweling of wood panels

Panel products have been joined to levels satisfying the requirements of the relevant standards for metallic connector assemblies by rotation welding of beech dowels through them. The wood panels substrates such as particleboard, OSB and MDF welded to the dowels almost as well as solid timber. Welded-through dowel assemblies presented better stiffness of the test joints than similar assemblies of dowelled solid timber.

Load Bearing Capacity of Connections in Tempered Glass Structures

In the design of high load bearing capacity beams made of tempered flat glass, connections cannot be avoided when large-span or high-stiffness beams are considered. The aim of this paper is to contribute to a method to calculate the load bearing capacity that can help the design of dowel type joints in tempered glass structures in buildings. The technology presented is derived from the one used for hanging glass in facades. In a first step, residual stresses due to thermal tempering are modelled with the Finite Element Method. Narayanas-wamy’s model is used to describe the thermo-mechanical behaviour of glass. The different heat transfers are identified and modelled for a given tempering process. In a second step, the state of stresses due to the loading of the metallic connector is analysed. The numerical prediction of stresses is validated by means of experiments. The superposition of these two stress states is combined to get a design criterion for holed tempered glass plates loaded by dowel type joints.

Sur le dimensionnement des structures en verre trempé

ABSTRACT This work deals with the use of glass as a real structural material, and concerns more particularly the detailed study of the potentiality of a connection by insertion of a steel dowel in a hole of a glass plate, in the aim of the making of long beams or beams with large inertia. The determination of the optimal geometry for such a connection passes first by the superposition of two stress states (the first one is generated by the thermal tempering and the second is due to the loading of the metallic connector in the plane of the glass plate). Then a design method ensuring the durability of the structure is proposed.

Sur le dimensionnement des structures en verre trempé

This work deals with the use of glass as a real structural material, and concerns more particularly the detailed study of the potentiality of a connection by insertion of a steel dowel in a hole of a glass plate, in the aim of the making of long beams or beams with large inertia. The determination of the optimal geometry for such a connection passes first by the superposition of two stress states (the first one is generated by the thermal tempering and the second is due to the loading of the metallic connector in the plane of the glass plate). Then a design method ensuring the durability of the structure is proposed. MOTS-CLES : verre structural, connexions, trempe thermique, transferts de chaleur, elements finis, fractographie, photoelasticite

Pseudofracture of an ICD lead.

A proximal pseudofracture of a Medtronic 6936 defibrillating lead adjacent to the ICD pulse generator was found on X ray. At this site, the multifilar metallic connector joins the stimulating lead before coiling around it. Conventional X ray of the abdomen does not visualize this connection. During ICD replacement, lead impedance should be routinely measured.

LXI. On a metallic connector to replace the vulcanite tube used with Bianchi's air-pump

LXI. On a metallic connector to replace the vulcanite tube used with Bianchi's air-pump