Rubber Ring Research Articles

Selection of the geometric parameters of disposition unit of rubber O-ring seals

0.025 relative deformation of the ring in the zone of its contact with the slanted surfaces of the groove. In the course of time the elastic properties of rubber change. This time may be regarded as the holding (storage) time of the seal after its assembly up to the onset of operation (increase of the pressure of the working medium) or as the time of operation of the seal under pressure up to its normal decrease. In the former case the indispensable preliminary deformation of the rubber ring has to compensate for the change of the elastic properties of the rubber in time so that at the end of the holding time the residual elastic relative deformation is not smaller than the recommended deformation e0', i.e.,

Comparison of the Burdizzo and rubber ring methods for castrating and tail docking lambs

The behavioural and plasma cortisol changes in groups of six lambs, five to six days old, were used to compare the acute effects of four methods of castration and tail docking: Burdizzo, standard sized and small rubber rings, and a combined method in which the application of a standard rubber ring was followed immediately by the application of the Burdizzo just distal to it. A control group was also included. Active behaviours such as foot stamping and restlessness increased markedly only after the treatments with rubber rings. Less time was spent in abnormal postures, and the increases in plasma cortisol were least after the combined method. It was concluded that the lambs treated by all the methods suffered considerable acute pain, for up to three hours in some cases, but that the combined method produced the least pain as judged by the behavioural and physiological indices measured, and that the small rubber rings produced more intense pain for a shorter time than the standard rubber rings.

Iatrogenic gastroschisis decreases pulmonary hypoplasia in an ovine congenital diaphragmatic hernia model.

Pulmonary hypoplasia is a major problem in infants with congenital diaphragmatic hernia. Intrauterine reparative procedures are associated with a high complication rate. The development of less complex operations to reduce the degree of fetal lung hypoplasia may improve neonatal survival. Our objective was to investigate the effectiveness of an iatrogenic gastroschisis in reducing fetal pulmonary hypoplasia in a sheep model with an artificially created diaphragmatic hernia. A left-sided diaphragmatic hernia (Bochdalek type) was created at 75 days' gestation in an ovine fetal model during the pseudoglandular phase of lung development. At 110 days' gestational age, a left-sided gastroschisis was created by excising part of the lower abdominal wall and buttressing the opening with a rubber ring. The fetus remained in utero until 135 days' gestation, at which time it was sacrificed for autopsy. Histopathologic and morphometric studies were performed on the lungs. Ten animals had creation of a diaphragmatic hernia. Four underwent the second surgery to create a gastroschisis. One animal completed the entire protocol, 3 fetuses aborted after the second surgery. Autopsy confirmed effective decompression of the herniated abdominal contents from the chest into the amniotic cavity in all 4 cases. The lungs of the animal that completed the protocol were appropriately developed, while those fetuses that died soon after gastroschisis creation had severe pulmonary hypoplasia, mainly involving the left lung. Artificially induced diaphragmatic hernia, in the ovine fetus, causes severe pulmonary hypoplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Noise isolating motor mounting system for a canister vacuum cleaner

An arrangement for mounting a motor blower assembly (24) in a canister vacuum cleaner uses a pair of resilient rubber rings (36, 42), one each on the front and rear of the assembly, to isolate the motor from the vacuum cleaner housing (12). The front ring (36) goes over the front of the fan casing (28) and is trapped within the housing (12), while the rear of the motor (26) has attached thereto an adaptor (40) which fits within the complementarily shaped rear rubber ring (42). This rear rubber ring (42) in turn fits within a complementarily shaped motor support (44), which is attached to a support abutment (54) within the housing (12). In order to accommodate different size motors within the same housing and utilize the same mounting components, the support abutment (54) is pre-drilled at various locations (58) to accommodate the different size motors. Thus, the only fixed attachment to the housing (12) is the rear support (44), which is isolated from the motor blower assembly (24) by the rear rubber ring (42).

Experience in operating and reconstructing the turbine bearings of units of the Sayano-Shushenskoe hydroelectric station

The 15-year operating experience showed that the right choice of the design of the guide bearing was made. Today it can be considered among the most reliable components of the turbine. The existing opinion about the higher reliability of only rubber ring and oil bearings is not quite correct; where the specifications allow, one can safely use the design of a segmental turbine bearing with water lubrication.

Effect of different methods of castration on behaviour and plasma cortisol in calves of three ages

Calves of six, 21 and 42 days were either handled (controls) or castrated by Burdizzo, by surgical or by rubber ring techniques and their behaviour and plasma cortisol monitored for three hours after treatment. The rubber ring caused significant increases in active behaviour and abnormal postures for two hours compared with handled or castrated by Burdizzo and surgical techniques, and surgical techniques resulted in a significant increase in abnormal standing, particularly in the first 30 minutes. Abnormal behaviour and posture were recorded less frequently in six-day-old calves. The mean cortisol peaks for six-, 21- and 42-day-old calves were, respectively, 36, 31 and 23 nmol litre −1 in the handled groups; 60, 43 and 48 nmol litre −1 in the rubber ring groups; 77, 50 and 62 nmol litre −1 in the Burdizzo groups; and 106, 63 and 107 nmol litre −1 in the surgical groups. The greatest cortisol response occurred in 42-day-old surgically treated calves and the shortest response after Burdizzo castration. These responses suggest that irrespective of age, all methods of castration studied caused acute pain. Burdizzo castration appeared to produce the least pain, particularly in younger calves.

Field Measurement Results of TLP Dynamic Responses and Strength Assessment of Parallel Wire Strand Tendon

This paper deals with the measured data obtained through the at-sea measurement of the TLP “EHIME”, an offshore nursery pilot firm station of Marino-Forum 21, of which tendons are parallel wire strands (PWS) protected by polyethylen sheath with specially manufactured cushion rubber rings at each ends and connected to a gravity type template through a belimouth shape structure. The measured data of the TLP dynamic responses are compared with theoretical estimation, and the strength performance of PWS as TLP tendons are discussed.The main results are as follows; 1) the TLP with the PWS mooring system has the same dynamic response characteristics as the conventional TLP with the steel pipe mooring system, 2) the mooring system by use of PWS type tendons adopted for the TLP “EHIME” exhibits sufficient strength and durability characteristics.

Changes in plasma cortisol concentration in lambs of three ages after three methods of castration and tail docking

Lambs were handled only or castrated and tail docked at five, 21 and 42 days of age by either surgery, rubber ring or rubber ring and Burdizzo. Plasma cortisol was measured in blood samples taken before and at 12, 24, 36, 48, 60, 72, 84, 96, 138 and 180 minutes after castration and docking. Pre-treatment and peak cortisol values were highest in five-day-old lambs. The peak cortisol values, at each age, were similar for surgery and rubber ring groups. However, the peak occurred earlier after surgery and rubber ring Burdizzo than after rubber ring only treatment. The cortisol peak was 28 nmol litre −1 lower after rubber ring Burdizzo than surgery or rubber ring only. Plasma cortisol returned to pretreatment values within 84 minutes after rubber ring Burdizzo, 96 to 138 minutes after rubber ring only but not within 180 minutes after surgery. The changes in plasma cortisol together with the changes in behaviour suggest that the rubber ring Burdizzo method of castration and docking of lambs at all ages, was probably the least painful of the methods tested.

Behavioural responses of lambs of three ages in the first three hours after three methods of castration and tail docking

The behavioural responses of groups of seven lambs were compared with control groups after castration and tail docking by rubber rings, application of a Burdizzo clamp in addition to a rubber ring and after surgical castration at five, 21 and 42 days. All methods at all ages produced changes in behaviour which were interpreted as indicative of considerable pain. The rubber ring groups showed most changes in behaviour at all ages. The rubber ring with Burdizzo groups showed least changes and some lambs in these groups showed much less response than others. The surgical groups showed some behavioural responses which were different, both qualitatively and quantitatively to those in other groups. It is concluded that indices used for recognition and assessment of acute pain received conditional support, that modification of the rubber ring with Burdizzo may provide the least painful method without local anaesthesia and that age had little effect on the responses.

Laboratory demonstration of oviposition by Aedes aegypti (Diptera: Culicidae) in covered water jars.

In Thailand, ceramic jars (135-200 liters) covered by aluminum lids commonly are used to store water for household use. In laboratory cages, gravid female Aedes aegypti (L.) were able to enter and oviposit in a covered water jar. Although the aluminum lid was not a complete barrier to gravid females, it reduced the number of eggs oviposited by 77%. A vertically oriented foam rubber ring which was compressed between the lip of the jar and the flange of the lid effectively sealed the jar against ovipositing mosquitoes.

Standard reversible transducer (USRD type E37) for high frequencies to 2.0 MHz at hydrostatic pressures to 20.7 kPa (3000 psi)

A new pressure‐stable reversible standard transducer, USRD E37, has been developed at the Naval Research Laboratory, Underwater Sound Reference Detachment for the frequency range 100 kHz to 2.0 MHz at hydrostatic pressure to 20.7 MPa (3000 psi) with operating temperatures from 5 to 35 °C within this frequency range. This USRD E37 maintains a smooth response over the broad frequency spectrum previously covered by both the USRD E27 and E8 standard transducers, which were not stable with temperature and static pressure. The E37 has been calibrated to 6894 kPa (1000 psi) at 3 °C. Its unique sensor configuration design uses a lead titanate disc sensor supported by a butyl rubber ring. The faces of the sensor are covered with PRC PR‐1538 polyurethane and are held in place in the frame assembly by thin wire. The receiver preamplifier assembly is specially designed for high‐frequency operation, with a built‐in bypass relay to allow signals to be transmitted. The cylindrically designed outer housing is made of polycarbonate and has been statically pressure tested to 31.026 MPa (4500 psi).

Final version of the pick-up wheels in the Pelletron tandem accelerator at Lund

A new type of pick-up wheel has been designed and constructed for the charge transport system of the Lund 3UDH Pelletron tandem accelerator. The major improvements compared with older types are a slender design with only one ball bearing and more robust contact pins with a rubber ring between the pinhead and the wheel nave.

A new double-purpose device for elbow extension in tetraplegia with paralysis below C5

A new device for elbow extension, developed as a dynamic orthosis and also as a static splint for a C5 tetraplegic arm, is presented. A patient with tetraplegia, probably related to infection of the central and peripheral nervous system, had a paralysed right triceps muscle, with a very strong corresponding biceps. Extension by force of a posterior stretched rubber ring made the arm useful, while the possibility to lock the elbow hinges of the orthosis at any desired angle enabled static splinting of the elbow to increase the range of motion.

A new gadget to solve the problem of leaking gastrostomies

A new gadget for leaking gastrostomies is described, made from a flat rubber ring (washer, used in plumbing) through which a Foley catheter is passed; this rubber ring fixes the balloon of the catheter and prevents leakage from the stomach.

Superoxide Dismutases and Anti-Oxidants Protected Mice from no-Reflow and Necrotic Damage Induced by Ischemia

A simple method in mice was established to screen anti-ischemic compounds. Thirteen times binding of rubber ring (1 x 1 mm, d = 42 mm) for 4.5 hrs, swelled the paws of 60% mice applied and 14 times binding swelled only of 5% mice. Critically reversible limit lay between these conditions. "All or none" rule dominated the paw swelling perhaps due to different endogenous anti-oxidants' levels of individual mice. Determination of paw reversibility at 90 min of recirculation, was proved to be suitable. Swollen paws at this time returned normal and the paws with no-reflow dropped out by muscle necrosis after several days. Intravenous (i.v.) bovine Cu, Zn-SOD and bacterial Mn-SOD (3-10 x 10(4) U/kg) or liposomal Cu, Zn-SOD (0.3-3 x 10(4) U/kg) were protective (35-50%) by 14 times binding. Allopurinol (10-100 mg/kg) and D-mannitol (3-30 mg/kg) was effective (25-55%). Catalase (i.v., up to 10(5) U/kg) showed little protection, but local injection of 100 U/kg resulted in 50% protection. Glutathione (30 mg/kg) was suppressive only by local injection suggesting the importance of administration route. Desferal, heparin and nitric oxide synthesis inhibitor showed some protection, but indomethacin, mepyramine, ascorbate, vitamin E and dexamethasone were without effect. Excess dosing of all anti-oxidants tested, dramatically decreased their effects demanding caution for therapeutic trials.

Cortisol responses of young lambs to castration and tailing using different methods

Lambs at 4-5 weeks of age were studied during the first 4 hours after castration and/or tailing using three methods in various commonly used combinations. The methods were cutting with a knife, application of constricting rubber rings and using a heated docking iron (tailing only). The integrated cortisol response (area under the cortisol curve) was determined for each lamb during the first 4 hours after treatment and was considered to reflect the overall magnitude of the lamb's acute distress response. On that basis, cut lambs (tailing only, castration only, castration plus tailing) experienced more distress than any other groups. Also the distress response (indicated by elevated plasma cortisol concentrations) lasted longer than 4 hours in cut lambs, unlike all other groups. The use of rings apparently caused similar distress when lambs were castrated only, were castrated plus tailed, or were short-scrotumed (testes pressed against the abdominal wall by a distally located scrotal ring) plus tailed. The magnitudes of distress apparently caused by tailing alone with a ring or a docking iron were similar and were lower than the distress caused by any other castration and/or tailing procedure. It is concluded that acute distress responses to these husbandry procedures would be minimised in lambs of this age if rings and/or a docking iron were used in preference to a knife.

Nonstandard method of sealing with rubber rings

Nonstandard method of sealing with rubber rings

Effects of local anaesthesia and intravenous naloxone on the changes in behaviour and plasma concentrations of cortisol produced by castration and tail docking with tight rubber rings in young lambs

The reliability of some behavioural and physiological indices used for the recognition and assessment of acute pain in lambs after castration and tail docking has been examined. Changes in the indices were measured after blocking neural activity with local anaesthetic (lignocaine) and after an opioid antagonist (naloxone) was administered. Six lambs, aged less than one week, were allocated randomly to each of six treatments. (i) control handling and blood sampling; (ii) castration plus tail docking with tight rubber rings; (iii) local anaesthesia; (iv) local anaesthesia followed by castration and tail docking; (v) intravenous naloxone only (0·2 mg kg −1); and (vi) intravenous naloxone followed by castration and tail docking. Local anaesthesia eliminated the behavioural and plasma cortisol changes which usually follow castration and tail docking. Naloxone had a limited effect on the increase in cortisol but altered the behaviour. The results support the view that such indices are useful for assessment of the response to acute pain and that, although endogenous opioids do reduce pain in young lambs after castration and tail docking, the effect is small.

Effects of castration on behaviour and plasma cortisol concentrations in young lambs, kids and calves

Behavioural and cortisol responses to the husbandry practice of castration with tight rubber rings were investigated in lambs and kids one day after birth and in hand reared calves aged one to seven days. There were three treatments: control handling and blood sampling, castration and, in lambs and kids only, intravenous adrenocorticotrophin injection ( ACTH). The integrated cortisol responses (area under the cortisol curve) in lambs and kids were least in control, intermediate in castrated and greatest in ACTH animals. No cortisol responses were detected in control or castrated calves. The incidences of behaviour used to assess the intensity of distress apparently experienced in the different species corresponded generally with the magnitudes of the cortisol responses. Behavioural and cortisol responses together suggested that the distress caused by castration was greatest in lambs, intermediate in kids and least but not necessarily absent in hand reared calves.

Biocatalytical Membrane Electrode for Phenol

Abstract A microbian sensor for phenol, based on an amperometric sensor for oxygen, was achieved; a thin layer of biocatalytic material (intact microbian cells of Rhodotorula species) was deposited on its surface and maintained there by means of a dialysis membrane, fastened with a rubber ring. The sensor so achieved had better response characteristics than similar sensors reported in literature. It has a liniar response to phenol up to a concentration of 9.0 mg/L. The response time is only 5 to 10 sec. for kinetic method and 30 sec. if the steady state method is used. The influence of pH and temperature on the electrode response, as well as its stability, were also investigated.