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Notched sample modeling was used to demonstrate effect of technology used for manufacturing pipes from steel 10Kh9MFB-Sh (piercing-broaching or electroslag remelting) on metal fracture toughness under creep conditions of 600°C at subcritical and avalanche stages of destruction. According to the subcritical crack growth and metal fracture toughness resistance determined on the samples, the lifespan of pipes having initial defects was evaluated. Calculations were carried out for pipes of two types including a hot reheat (HRH) steam line operating under a pressure of 4.1 MPa and a main steam (MS) line operating under a pressure of 14.0 MPa. Taking into account the obtained characteristics of fracture toughness, the use of electroslag remelting technology was shown to provide a durability of about 3 times that of piercing-broaching approaches. Differences in the pressure level and wall thickness shown to result in a tenfold increase in the durability of the HRH and MS steam pipelines at 600°C justify a different cracking risk classification, which should be taken into account in conducting operational monitoring.

(Ultra) high-pressure homogenization ((U)HPH) is one of the emerging technologies being studied and developed for various applications in the food industry. (U)HPH was suggested as an effective tool for achieving microbial safety and extending the product shelf life of liquid foods in a continuous process while minimizing some negative attributes of thermal processing. The valve geometry, pressure level, inlet temperature, and the number of homogenization cycles are all factors affecting the level of microbial inactivation and the extent of the techno-functionalities of food biopolymers and matrices. Turbulence, high shear, cavitation, and temperature increase induced by (U)HPH treatments enhance emulsion stability, stabilize proteins in solutions, reduce particle size distributions, and increase the accessibility of health-promoting compounds. This review is a comprehensive and updated overview of the engineering aspects of the (U)HPH process, specifically focusing on (U)HPH modification of food components such as polysaccharides, proteins, and bioactive compounds. A detailed description of the potential applications in food products beyond microbial inactivation is also included.

Spatial, vertical and temporal variations in the subtropical jet stream over Africa and the Middle East were studied from 1958 to 2016 using NCEP/NCAR reanalysis meteorological data. The results of this study showed that the jet stream was located at a pressure level of 200 hPa more than 87% of the time, and it was located in the meridional zone between 20°N and 35°N in more than 83% of these cases. Additionally, the annual winter distribution of the jet stream illustrated two distinct trends: the first trend ended in 1987 and had a high rate of decrease, and the second trend began in 1988 and had a small rate of increase. Furthermore, synoptically, the study showed that the southern shift of the jet stream intensified the low-pressure systems over Africa and the Mediterranean, in addition to producing favorable conditions for the northward extension of the Red Sea Trough. However, the northward shift was related to the intensified Azores high-pressure system over Africa and the southern Mediterranean. Moreover, the temporal variations of the jet stream indicated that the intensification of the high-pressure system (i.e., the Azores and Siberian highs) tended to decrease the number of jet stream cases at 200 hPa or vertically shifted them downward to 250 hPa.

This paper provides the methodology to achieve pseudo 1-D combustion system of specific polymeric materials without any complex physical effect (e.g., deformation, bubble bursting etc.) by adopting a low pressure technique with a fuel-layered approach. The adopted pressure level in this study is as low as 20 kPa and the size of the specimen is sub-millimeter scale. By utilizing pressure modeling to keep the Grashof number small, the gravity effect is relatively minimized at low pressure to mimic an ideal 1-D combustion process. A molten PMMA layer formed over a ceramic ball (suspended by thin SiC fiber) was used as the burning specimen to fulfil the purpose of this study. Results show that a spherical flame without any apparent bubble bursting is successfully achieved during the entire burning event when the pressure is sufficiently lower (~ 20 kPa) for both 20% and 30% ambient oxygen concentration. A well-known d-square law and pseudo steady burning process is confirmed at the post-ignition stage. Direct comparison of burning rate, K, between what was obtained in this study and that obtained under microgravity ensures that the present methodology is effective to simulate an ideal 1-D combustion system, just like one that can be achieved in microgravity, without the need for microgravity facilities.

This research was aimed at exploring and evaluating high pressure processing (HPP) as a technique for calcium infusion into baby carrots. HPP was employed in infusing calcium in pectin methylesterase (PME) pre-treated baby carrots using infusate solution of calcium lactate gluconate (CLG). Experiments were performed following a Box-Behnken design to evaluate the effects of pressure, holding time, and CLG concentration on the extent of calcium infusion (amount infused per serving size (85 g) of baby carrots) and the hardness of baby carrots using single pressure cycle. In addition, the effect of pressure cycling on the extent of calcium infusion was also studied by varying the number of high pressure cycles at 1, 3, and 5 at a fixed pressure (550 MPa) for a total holding time of 15 min and using 9% (w/v) CLG solution. HPP enhanced the infusion of calcium from 19.5 mg/serving in raw baby carrots to 134 mg/serving at 350 MPa–10 min–9% CLG, which was more than 3 times the amount of calcium infused in osmotically and vacuum infused controls. Pressure level, time, and CLG concentration had significant effects on calcium infusion. Increasing the number of pressure cycles increased the amount of calcium infused. The calcium infused baby carrots had higher hardness than raw unprocessed carrots.

In this paper, the constitutive framework of hypoplasticity is used to model long-term deformations and stress relaxations of weathered and moisture sensitive rockfill materials. The state of weathering of the material is represented by a so-called solid hardness in the sense of a continuum description. The time-dependent degradation of the solid hardness is a result of progressive weathering caused for instance by hydro-chemical reactions of fluid with the solid material. The degradation of the solid hardness can lead to collapse settlements and creep deformations, which are also called wetting deformations. In contrast to a previous version, a new evolution equation for a more refined modelling of the degradation of the solid hardness is proposed. With respect to a pressure-dependent relative density, the influence of the pre-compaction of the material and also the influence of the pressure level on the stiffness can be modelled in a unified manner using a single set of constants. The performance of the new model is validated by comparison of the numerical simulations with experiments data.

An increasing amount of evidence has been shown to support the use of blood flow restriction (BFR) in combination with low-load resistance exercise to enhance morphological and strength responses. The BFR technique involves applying a tourniquet cuff to a limb and pressurizing it with a tourniquet instrument to restrict, but not fully occlude, arterial blood flow into the limb during rehabilitative exercise. A review of BFR rehabilitation literature shows that inconsistencies exist in methodology, equipment and in levels of restriction pressure used. Current non-personalized methodologies of setting BFR pressure may occlude rather than restrict blood flow, increasing the risk of injury during rehabilitation. Furthermore, these non-personalized methods of setting pressure do not provide a consistent stimulus within and across patients, reducing the efficacy of the BFR rehabilitation and inhibiting the meaningful comparison of a full range of BFR studies. A restriction pressure level set for each individual patient, based on a percentage of limb occlusion pressure (LOP) measured at rest, and applied using a surgical-grade tourniquet cuff, enables those individual patients to receive a safe and consistent BFR stimulus compared to other methods of setting the restriction pressure level. In view of the above, it is crucial to use surgical-grade tourniquet technology with automatic LOP measurement capability, adapted to incorporate and deliver optimal protocols, for safe and effective application of BFR to consistently achieve optimal patient outcomes in rehabilitation.

Major challenges in modelling and forecasting fog are determining the accuracies needed in simulation of meteorological fields that determine the dynamics of fog. In particular, the meso-scale forecasts need to be tested for their ability to distinguish between foggy and non-foggy days for the important variables like wind, humidity and temperature. We evaluate forecasts from a meso-scale atmospheric model over Delhi (28°35′N; 77°12′E), a fog fog-prone metropolis, during the months December and January through 2009–2012. A comparison of composites of hourly forecasts of the meteorological fields of area-averaged 1° × 1° (28°35′N; 77°12′E) surface wind, low-level humidity and air temperatures for the observed foggy and non-foggy days shows that the forecasts do show lower winds, higher humidity and lower temperature in general for foggy days consistent with the known physical conditions for formation of fog over the region. Comparison of differences in simulated meteorological variables for days with no fog, mild fog and dense fog (characterized in terms of hourly visibility) with the corresponding values from observation show consistent and appreciable distinctions in the meteorological variables The contrasts are also found to persist at 850 mb pressure level in both observed and the simulated profiles; once again the observed vertical profiles have distinct characteristics for December and January that are simulated well by the model. Identification of these contrasts can help to calibrate model configuration and to quantify accuracy required in the meteorological forecasts for driving fog prediction models.

Changes in functional properties of rice bran proteins as influenced by high-pressure (HP) treatment (100–500 MPa, 10 min) were studied. Properties evaluated were protein solubility, water absorption capacity, oil absorption capacity, foaming capacity, foam stability, emulsifying activity, emulsion stability, least gelation concentration, and surface hydrophobicity. HP treatment at 100 and 200 MPa significantly improved the solubility and oil absorption capacity, while water absorption and foaming capacities increased further reaching the maximum at 500 MPa. Compared with the untreated control sample, the emulsifying activity and foam stability of treated samples were significantly higher and least gelation concentration was lower, but none of them showed any specific trend with pressure level. Emulsion stability and surface hydrophobicity increased with the pressure level until 400 MPa and decreased slightly at 500 MPa. Pearson correlation coefficients clearly showed that surface hydrophobicity was positively correlated with water absorption capacity, foaming capacity, emulsifying activity index, and emulsion stability index, but negatively correlated with least gelation concentration. The pressure treated rice bran protein possessed good functional properties for use as a food ingredient in the formulations.

Four factors have been reported to affect brace treatment outcome: (1) growth or curve based risk, (2) the in-brace correction, (3) the brace wear quantity, and (4) the brace wear quality. The quality of brace design affects the in-brace correction and comfort which indirectly affects the brace wear quantity and quality. This paper reported the immediate benefits and results on using ultrasound (US) to aid orthotists to design braces for the treatment of scoliosis. Thirty-four AIS subjects participated in this study with 17 (2 males, 15 females) in the control group and 17 (2 males, 15 females) in the intervention (US) group. All participants were prescribed full time TLSO, constructed by either of the 2 orthotists in fabrication of spinal braces. For the control group, the Providence brace design system was adopted to design full time braces. For the intervention group, the custom standing Providence brace design system, plus a medical ultrasound system, a custom pressure measurement system and an in-house software were used to assist brace casting. In the control group, 8 of 17 (47%) subjects needed a total of 11 brace adjustments after initial fabrication requiring a total of 28 in-brace radiographs. Three subjects (18%) required a second adjustment. For the US group, only 1 subject (6%) required adjustment. The total number of in-brace radiographs was 18. The p value of the chi-square for requiring brace adjustment was 0.006 which was a statistically significant difference between the two groups. In the intervention group, the immediate in-brace correction as measured from radiographs was 48 ± 17%, and in the control group the first and second in-brace correction was 33 ± 19% and 40 ± 20%, respectively. The unpaired 2 sided Student’s t test of the in-brace correction was significantly different between the US and the first follow-up of the control group (p = 0.02), but was not significant after the second brace adjustment (p = 0.22). The use of the 3D ultrasound system provided a radiation-free method to determine the optimum pressure level and location to assist brace design, resulting in decreased radiation exposure during follow-up brace evaluation, increased the in-brace correction, reduced the patients’ visits to both brace adjustment and scoliosis clinics. However, the final outcomes could not be reported yet as some of patients are still under brace treatment. NCT02996643 , retrospectively registered in 16 December 2016

This study investigated the effect of hydrostatic pressure processing (HPP) on post-rigor mortis beef (Longissimus dorsi muscle, Nelore breed) relevant parameters, such as texture, cooking loss, and color. Pressures varying from 100 to 400 MPa at different times of pressurization (T1: time to reach set pressure, and T2: T1 plus 15 min) were applied, immediately followed by depressurization. Samples were evaluated for color, cooking loss, and tenderness. Both pressure level and pressurizing time had an effect on the color, cooking loss, and tenderness. Low-pressure levels (up to 200 MPa) had a smaller impact on color; nevertheless, it improved tenderness. The cooking loss increased with increased levels of pressure; however, by increasing pressure to 100 and 200 MPa immediately followed by pressure release (T1), no significant differences were observed when compared to the results from unpressurized samples. On the other hand, cooking loss was higher in the beef pressurized at all pressure levels for 15 min (T2). The results show that treatments using lower pressures (100 to 200 MPa) can potentially contribute to Zebu meat quality improvement.

A current letter to the editor of this journal Bell (Acoust. Aust., 2015) draws attention to technology being pursued by NASA New Scientists (http://www.newscientist.com/article/dn27696-silence-of-the-drones-how-to-quiet-that-annoying-aerial-buzz.html#.VYyl4UbD_pI, 2015) concerning multi-propeller noise reduction via phase de-synchronisation. Bell points out that this technology could be used to help reduce noise from wind farms. This note presents some mathematical modelling that supports the ideas expressed by Bell and illustrates how it is possible, at least theoretically, to have regions of high-sound pressure level about a wind farm when turbines operate in phase.

Despite progress in shunt valve technology, CSF overdrainage is still one of the most frequent complications in shunt-treated hydrocephalus. Particularly with regard to young and adolescent patients, treatment of manifest overdrainage is complicated by several hardly influenceable factors such as increasing height and mobility. Therefore, the aim of this study was to evaluate the therapeutic efficiency of the new adjustable gravitational valve, proSA. Sixty-four shunt-treated young hydrocephalus patients aged 1.8–41.4 years (15.5 ± 10.5 years) suffering from clinical and/or radiological overdrainage underwent shunt revision surgery with the implantation of the new proSA valve. Clinical outcome after a 1-year follow-up period, pumping function of the valve chambers as well as the number of necessary postoperative valve adjustments were examined. Fifty-five patients completed the study as planned. All reported a significant improvement of their clinical condition; 91 % described a complete resolution in symptoms related to overdrainage. Preoperatively, more than 85 % of the valve chambers showed no or very slow refilling with CSF. After a year of proSA treatment, more than 90 % exhibited a normal valve chamber function. During the follow-up period, a total of 136 valve adjustments were necessary. None of the proSA valves had to be surgically revised. The postoperative adjustability of the opening pressure level is the advantage of the new gravitational valve. The good clinical outcome is attributed to the new valve technology. The proSA appears to be a promising shunt valve to overcome overdrainage in adolescent and adult hydrocephalus patients.

In the present paper cluster analysis of 2-month air mass back-trajectories for three contrasting fire and non-fire events is conducted (high, low, and zero burnt area). The large fire event displays an air mass history dissimilar to other events whereby a 39-day period of warm and dry chiefly northerly anticyclonic conditions is evident, before a week of warmer predominantly southwesterly cyclonic activity, immediately prior to ignition. The pressure level of these anticyclonic air masses is above 800 hPa for more than 75 % of the trajectory length; this region is above the principal moisture transport regime of 800 hPa altitude. Analysis of variance on the mean rate of change of potential temperature identified weak statistically significant differences between two air mass pairs regarding the large fire: anticyclonic and cyclonic air masses in both cases (p = 0.038 and p = 0.020). Such regularity of type and occurrence, approach pressure levels and statistically significant differences are not evident for the small and non-fire event air masses. Such understanding is expected to permit appropriate steps to be undertaken including superior prediction and improved suppression strategy.

Pressure applied during harvesting of the saphenous vein (SV) graft in coronary artery bypass surgery might change its mechanical properties and thereby decrease the patency. This study was performed to assess the mechanical properties of the SV graft distended manually with different levels of pressure and to determine the pressure level that induces changes in its structure and mechanics. Saphenous vein graft segments, collected from 36 patients undergoing coronary artery bypass surgery, were distended with pressures of either 50-60, 75-100, or 130-150 mmHg. Grafts were tested for the stress-strain relationship; the Young's moduli at the low- and high-strain regions were calculated, and their structures were examined by light and electron microscopy. Pressures of 50-60 mmHg did not influence the mechanics of the vein graft, whereas pressures of 75-100 mmHg elevated the elastic modulus of the vein at the low-strain region while pressures above 130 mmHg increased the elastic moduli at both low- and high-strain regions. There was a prominent loss of microfibrils at all distending pressure levels. The mechanical results suggest that distending pressures above 75 mmHg might play a role in graft failure. Furthermore, the absence of microfibrils surrounding elastin suggests that application of distending pressures, even as low as 50 mmHg, can cause degeneration of the elastic fibers following implantation, increasing the stiffness of the graft and thus impairing the graft's function under its new hemodynamic conditions.

Preventing sudden changes in intraabdominal pressure (IAP) during surgical pneumoperitoneum may reduce adverse events. This study aimed to describe a valve system that stabilizes intraabdominal pressure, minimizing complications of erratic fluctuations in IAP. Five male Sprague-Dowley rats were submitted to pneumoperitoneum, with the insufflator set sequentially at 5, 10, and 15 mmHg for each rat. Measures of IAP were taken initially without the valve and then using the same insufflator levels with the valve system regulated to three different pressures (5, 10, and 15 mmHg). The mean of the three highest registered pressures during a 15-min observation was used as the maximal pressure, and the mean of the three lowest registered pressures was used as the minimal pressure for each experimental setting. Without the valve system, the pressure level set by the insufflator correlated poorly with the actual IAP. When the valve system was used, the IAP pressure was limited by the valve settings regardless of the insufflator settings. Also, the variability of IAP was significantly higher when no valve was used than in all situations that had implementation of the system. The valve system was very effective in stabilizing IAP, allowing a reproducible and reliable estimate of IAP and greatly reducing the variability resulting from the cycling mechanism of the insufflator. Due to the small dimensions of intracorporeal cavities in the newborn, this mechanism may help to improve safety when neonatal video-assisted surgery is performed.

Synoptic geopotential height anomalies patterns favouring African dust outbreaks into the marine boundary layer (MBL) of the subtropical Eastern North Atlantic Region (SENAR) were objectively identified. The proportion of the total variance explained by each of these patterns was also calculated. Dust intrusions into the MBL of the SENAR were identified using total suspended particles (TSP) data at a rural background station in Tenerife Island (El Rio station, ER). Geopotential height anomalies at 1,000, 850, 700 and 500 hPa, respectively, in days of African dust intrusion in the period 1998–2003 were grouped in monthly sets. Two different but complementary methods (K-means and Principal Components) were applied to daily geopotential height anomalies for each month and for each pressure level in case of African dust intrusion. Three principal geopotential height anomalies patterns were found. Type I consist on a high-pressure system over Europe that affects North Africa, occasionally giving rise to a ridge. The Canary Islands are in the south-west flank of this high-pressure system. This pattern is dominant throughout the whole year. Type II and type III patterns consist on a low located to the northeast and southeast of the Canary Islands, respectively, coupled with a high over the Mediterranean basin and/or North Africa. Two case analyses are presented, as well as a systematic validation of the meteorological pattern classification for all dust intrusions detected at ER station within the period 2004–2007.

The frequency of low O2 (hypoxia) has increased in coastal marine areas but how fish avoid deleterious water masses is not yet clear. To assess whether the presence and oxygen pressure (PO2) level of an O2 refuge affects the hypoxia avoidance behaviour of fish, individual Atlantic cod (Gadus morhua L.) were exposed to a range of O2 choices in a 2-way choice chamber at 11.4°C over two different experiments. Cod in the first experiment were allowed access to a fixed O2 refuge (fully air-saturated seawater) whilst oxygen pressure (PO2) on the other side was reduced in steps to a critically low level, i.e. 4.3 kPa—a point where cod can no longer regulate O2 consumption. Under these conditions, cod did not avoid any level of hypoxia and fish swimming speed also remained unchanged. In contrast, strong avoidance reactions were exhibited in a second experiment when fish were again exposed to 4.3 kPa but the safety, i.e. PO2, of the refuge was reduced. Fish not only spent less time at 4.3 kPa as a result of fewer sampling visits but they also swam at considerably slower speeds. The presence of an avoidance response was thus strongly related to refuge PO2 and it is unlikely that cod, and possibly other fish species, would enter low O2 to feed in the wild if a sufficiently safe O2 refuge was not available. It is therefore hypothesized that the feeding range of fish may be heavily compressed if hypoxia expands and intensifies in future years.

To elucidate the potential of ultra high pressure (UHP) processing on ginseng, effect of UHP on extraction yield, crude saponin content, and ginsenoside contents of ginseng powder was investigated. Ginseng slurries (70, 80, and 90% moisture content) were put into a retortable pouch then hermetically sealed. These mixtures were pressurized at room temperature up to 600 MPa for 5–15 min. UHP ginseng showed relatively higher extraction yield (312.2–387.1 mg) and amounts of crude saponins (19.3–32.6 mg/g ginseng) than control ginseng (189.9 and 17.5 mg/g ginseng, respectively). Correlation coefficient between extraction yield and crude saponin content was relatively low (R2=0.2908). In high performance liquid chromatography (HPLC) analysis, amounts of measured total ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1) increased with UHP processing but pressure level and pressing time did not proportionally influence the ginsenosides content. This work shows a potential of UHP processing on extraction of ginseng powder and provides basic information on UHP extraction of ginseng powder.

The failure of certain wounds to heal (including diabetic foot ulcers) is a significant socioeconomic issue for countries worldwide. There is much debate about the best way to treat these wounds and one approach that is shrouded with controversy is hyperbaric oxygen therapy (HBOT), a technique that can reduce the risk of amputation in diabetic patients.In this paper, we develop a six species mathematical model of wound healing angiogenesis and use it to investigate the effectiveness of HBOT, compare the response to different HBOT protocols and study the effect of HBOT on the healing of diabetic wounds that fail to heal for a variety of reasons. We vary the pressure level (1 atm-3 atm), percentage of oxygen inspired by the patient (21%-100%), session duration (0-180 minutes) and frequency (twice per day-once per week) and compare the simulated wound areas associated with different protocols after three weeks of treatment.We consider a variety of etiologies of wound chronicity and show that HBOT is only effective in treating certain causes of chronic wounds. For a wound that fails to heal due to excessive, oxygen-consuming bacteria, we show that intermittent HBOT can accelerate the healing of a chronic wound but that sessions should be continued until complete healing is observed. Importantly, we also demonstrate that normobaric oxygen is not a replacement for HBOT and supernormal healing is not an expected outcome. Our simulations illustrate that HBOT has little benefit for treating normal wounds, and that exposing a patient to fewer, longer sessions of oxygen is not an appropriate treatment option.

We have shown the relationship between seasonal, annual, and large-scale variations in convective available potential energy (CAPE) and the solar cycle in terms of temperature at the 100-hPa pressure level using daily radiosonde data for the period 1980–2006 over Delhi (28.3°N, 77.1°E) and Kolkata (22.3°N, 88.2°E) and for the period 1989–2005 over Cochin (10°N, 77°E) and Trivandrum (8.5°N, 77.0°E), India. In general, there was a tendency for increases in CAPE to be associated with decreases in temperature at the 100-hPa pressure level on all time scales. Decreasing linear trends in temperature were found at Delhi and Kolkata over the period 1990–2006. Our analysis suggests that the trend towards increasing convective activity in the troposphere leads—at least partly—to the trend towards cooling in the tropopause region. High CAPEs are, in general, associated with high rainfall. The minimum annual temperatures were observed almost simultaneously with enhanced annual CAPE during the northern summer, with a larger anti-correlation (-0.62) over Delhi than at other stations. The influence of the solar cycle on the control of temperature was significant (∼4–5°C) only around 8–10°N. Temperature variations in the upper troposphere are viewed as being jointly controlled by CAPE and the solar cycle, with the respective contribution of each being location-dependent.

Differential scanning calorimetric determination of glass transition temperature in the freeze-concentrated matrix ( $$ T_{\text{g}}^{\text{'}} $$ ) of sea bass muscle was optimized. Conventional and modulated differential scanning calorimetry (DSC) techniques (using diverse cooling/heating rate and modulation parameters) and effect of an annealing step (−30, −20, or −15°C, 30min) were assayed. Transition was more evident using conventional DSC assays, cooling/heating rate: 10°C/min, annealing step at –20°C. A $$ T_{\text{g}}^{\text{'}} $$ value of –15.2 ± 0.3°C was observed for sea bass fresh muscle. This method was chosen for $$ T_{\text{g}}^{\text{'}} $$ determination on high-pressure (HP) treated and pressure shift freezing (PSF)—stored at –20°C—sea bass muscle. Thus, in both cases, transition at –15°C was less evident as a function of the pressure level applied, being very difficult to detect after treatment at 400 and 600MPa. It was observed that $$T_{\text{g}}^{\text{'}} $$ values were shifted to slightly higher temperatures (around 1°C higher) after HP treatment at 400 and 600MPa. The present work constituted a first approach to the study on the effect of HP on the glass transition of a complex food matrix, giving useful information about stability of the frozen food.

Many dynamic testing techniques use gas guns as a pressure generator. The pressure generated from the gas guns is often of low velocity and low energy and has a relatively random or short duration of a uniform pressure level. This kind of pressure is not well defined and cannot be converted into other application conditions. With aims at improving experimental capability and expanding the research horizon, a shock tube was designed and constructed; and innovative applications were explored. With proper adjustments of gas components and gas pressures, well-defined pressure sources could be produced. With appropriate designs of a force transformer, various testing parameters required for different, dynamic experiments could also be simulated. In this paper, a piston-like impactor was inserted into the shock tube as a pressure transformer. The feasibility of using the shock-tube-based facility for impact testing was demonstrated.

Effects of supercritical carbon dioxide (SCCO2) on the activity of horseradish peroxidase (HRP) in pH 5.6 acetate buffer solution were investigated. SCCO2 treatment could effectively inactivate HRP. Higher pressure, higher temperature, and longer treatment time caused more inactivation. The maximum reduction of HRP activity reached nearly 90% at 30 MPa and 55 °C for 60 min. Analysis of first-order reaction kinetic data (characterized by a rate constant k and by a decimal reduction time D) showed that D value was closely related to the pressure and temperature of SCCO2 treatment. Higher pressures or higher temperatures resulted in lower D values (higher k), the D value of HRP was minimized to 64.52 min treated by the combination of 30 MPa and 55 °C. The Zp, representing the range of applied pressure between which the D values change by a factor of 10, was 114.81 MPa. The activity of HRP treated by SCCO2 was reactivated significantly after initial 7-day storage at 4 °C apart from the samples at 30 MPa for 60 min, indicating the HRP inactivation may be reversible and the reactivation of HRP is dependent on the pressure level and treatment time.

A nanoparticle virtual impactor was constructed and its performance under different operating conditions was investigated. Experimental evaluations showed that the nanoparticle virtual impactor has a 50% cutoff size ranging from 15 to 60nm. Further, the cutoff size of 60nm can be achieved at an impactor chamber pressure of 220torr when the nozzle upstream pressure is 760torr. This pressure level is much higher than that of thin-plate orifice nozzle impactors, which require 12torr to achieve the cutoff size of 66nm. Thus, the proposed virtual impactor can be operated with a small vacuum pump, which is more preferable for practical applications.

Electromyographic investigations of tremor in aquanauts under the conditions of stimulated immersions are presented in this paper. The investigations were carried out before the aquanauts entered a barochamber, at specific pressure levels in the barochamber, under the conditions of decompression, and following emergence from the barochamber. The observed manifestations of the tremor under the conditions of increased pressure of trimix exhibited characteristics of parkinsonian tremor.

Materials and Methods In a series of 202 patients of different etiologies treated with the hydrostatic Dual-switch-valve (DSV), 22 cases were suspected of suffering from underdrainage. Using a new algorithm to differentiate between different causes of mechanical obstruction on the one hand and "functional" underdrainage, we saw an indication to exchange the DSV to one with a lower opening pressure in 15 cases.

The response of plasma and ventricular cerebrospinal fluid vasopressin concentration to short-time induced intracranial hypertension was studied in 8 patients with hydrocephalus, defined as ventricular enlargement on computerized tomography. In connection with measurement of conductance to cerebrospinal fluid outflow, the concentration of vasopressin in plasma and cerebrospinal fluid was measured during perfusion at a low (less than 10 mmHg) and at a high (greater than 20 mmHg) intraventricular pressure level. Mean plasma vasopressin concentration was increased from 2.4 +/- 0.4 pg/ml (SEM) during perfusion at the low pressure level to 4.2 +/- 0.8 pg/ml (p less than 0.01) at the high pressure level. The cerebrospinal fluid concentrations of vasopressin at the low and high intraventricular pressure were 1.2 +/- 0.1 pg/ml and 1.7 +/- 0.2 pg/ml (p less than 0.05), respectively. However, only half of the patients responded to the increase in intraventricular pressure with an increase in cerebrospinal fluid vasopressin concentration exceeding 50%. The results of the present study suggest that an increase in the intracranial pressure might be a stimulus for vasopressin release in both the blood and the cerebrospinal fluid.

The effect of large doses of dexamethasone (80 mg) on the cerebrospinal fluid pressure (CSFP) was investigated with continuous lumbar CSFP measurement over 24 h in 10 patients with supratentorial cerebral tumors and clinical signs of elevated intracranial pressure. There was a further slight rise in CSFP with an unchanged pressure pattern in the course of observation of the untreated control group. A marked lowering of CSFP was observed within 6 h after initial intravenous administration of dexamethasone to seven of the treated patients. In four of the treated patients an unequivocal and in five only a moderate CSFP lowering was measured at the end of the registration. One patient had a slight rise in pressure. The plateau waves of all the patients treated decreased in height, frequency and duration within the first hours, while fluctuations in pressure level and CSFP amplitude were reduced.

Ten strains of Clostridium botulinum (5 type A and 5 type B) were combined and tested for their ability to produce toxin in modified reinforced clostridial medium, pH 5.7, under different amounts of pressure of carbon dioxide at 30° C. At atmospheric pressure (101 kPa), 100% CO2 delayed toxin production when compared with an atmosphere of 100% N2. Increasing the pressure level of CO2 further delayed the onset of toxin production; however, CO2 at 891 kPa absolute did not totally inhibit production of toxin, as two of 10 samples became toxic between 4 and 8 weeks of incubation. Pressurized CO2 was lethal to C. botulinum, with the rate of decrease of recoverable colony-forming units being dependent on the amount of pressure of CO2 and the length of exposure. However, CO2 at 816 kPa absolute did not serve as a fully protective antibotulinal agent as some of the surviving spores were capable of germination and producing toxin within 8 weeks at 30° C.

Interactions between period and degree of pressure have been investigated in membrane and filament systems of gill tissue, skin, and muscles of Modiolus modiolus, Mytilus edulis (Baltic and North Seas) and Branchiostoma lanceolatum (Pallas) at the ultrastructural level. The results show the importance of time for the degree of structural disintegration at constant pressure. Destruction already occurs after 2 min of low-pressure treatment at 300 atm. After 10 min continued pressure at the same level, no further structural dis-organization (qualitative or quantitative) occurs, even when the time period is prolonged. For some organelles (i.e., cilia and microvilli), better structural preservation is apparent after 30-min pressure compared to 10-min treatment at the same pressure level. This is a so-called “acclimatisation” to pressure.

Effects of the workpiece surface vibration on planing noise were investigated theoretically and experimentally. A method of calculating the sound pressure level generated by the workpiece surface vibration due to the impact of planing knives was developed. Sound pressure levels and sound spectra calculated using this method show good agreement with measured values.

Rocketsonde monthly mean temperature structure of the stratosphere is compared with that derived from Nimbus-5 SCR radiance measurements for the solsticial months in 1973 and for the equinoctial months in 1974. The comparison shows good agreement only at pressure levels between about 5 mb and 15 mb (upper-middle stratosphere). The satellite minus rocket bias is highest at the stratopause region possibly due to the constraints applied in retrieving the radiance equivalent temperatures.

1. The substernal distress caused by esophageal distention with a balloon is characterized by a pressure rise to approximately 50–55 mm. Hg. This pressure level is relatively constant under a variety of conditions.

Dynamic loads generated in a shock tube were applied to the inner bore of annular specimens of a simulated solid propellant. The load pulse-shape was approximately triangular, with essentially zero rise-time, a duration of about 0.25 msec, and a variable intensity. At each particular pressure level the loading was repeated on a specimen until fracture of the specimen occurred. In this fashion it was possible to construct a low-cycle dynamic fatigue curve for the material used. It appears that a simple energy criterion describes the fracture behavior reasonably well.

The result of Electric Response Audiometry is a couple of response curves representing the neural activity in dependence on the sound pressure level of click stimuli. Speech Audiometry, basing on the “Freiburger Wortertest”, also reveals a dependence of the sound pressure level. In this case the dependent variable is the percentage of words, that is recognized at each pressure level.

Les auteurs ont etudie l'action de l'hypoxie sur la proliferation des megaloblastes dans l'anemie pernicieuse et ont mis en evidence un effet inhibiteur. Le phenomene est analogue a celui qui a ete demontre pour l'erythroblaste de la moelle osseuse normale, mais il en differe en ce sens que la sensibilite negative du megaloblaste est plus grande que celle du normoblaste. Il n'est pas encore etabli s'il s'agit d'une action specifique en rapport avec la biologie differente des deux cellules ou simplement liee a leur different degre d'activite proliferatrice, plus eleve pour le megaloblaste que pour le normoblaste.