Pressure-driven charge transfer and tunable superconductivity in intermetallic Li–Mg electrides

Creep behavior of the ZK60 magnesium alloy was investigated using impression creep technique. The tests were carried out under constant punching stress at high temperatures (175, 200 and 225 °C) under low stresses (25, 50, 75 and 100 MPa) and at low temperatures (100, 125 and 150 °C) under high stresses (100, 125, 150 and 175 MPa). The creep mechanism of the extruded ZK60 magnesium alloy is grain boundary sliding by dislocation climbing obtained at low temperature and high pressure. At high temperature and under low pressure, the creep mechanism of the extruded ZK60 magnesium alloy is grain boundary diffusion by grain boundary sliding. The initial microstructure of the extruded ZK60 magnesium alloy was composed of mainly Mg phase and a little MgZn phase. Under the conditions of low temperature and high pressure, MgZn2 phase precipitated during creep deformation. Under the conditions of high temperature and low pressure, MgZn2 phase and a small amount of Zr-Zn phase precipitated during creep deformation. The creep resistance of magnesium alloy ZK60 under the conditions of low temperature and high pressure is better than under the conditions of high temperature and low pressure.

Interstitial anionic electrons (IAEs) at lattice cavities of electrides, which have diverse morphologies and concentrations, can induce interesting physical and chemical properties. Understanding the correlation between IAEs and electron-phonon coupling is crucial for the development of new electride superconductors. We have applied first-principles structural search calculations to predict new high-pressure Li-As electrides, such as $P6/mmm {\mathrm{Li}}_{x}\mathrm{As}$ ($x=5$ and 8), ${\mathrm{Li}}_{6}\mathrm{As}$ with $Cmc{2}_{1}$ and $C2/c$ symmetries, and $C2/m\phantom{\rule{0.16em}{0ex}}{\mathrm{Li}}_{10}X$ ($X=\mathrm{As}$ and Sb), which together with the already known $C2/m\phantom{\rule{0.16em}{0ex}}{\mathrm{Li}}_{10}\mathrm{Te}$ compound present favorable characteristics (i.e., variable donor content, structural symmetries, and acceptor species) to explore IAE-related superconductivity. According to our results, the predicted superconducting temperatures of these electrides are positively correlated with the number and connectivity of IAEs.

Located at crystal voids, interstitial anion electrons (IAEs) have diverse topologies, which may be tuned to achieve different properties. Elucidating the role of IAEs in electron-phonon coupling (EPC), and using it to design electride superconductors, leads to the current prediction of superconducting ${\mathrm{Li}}_{8}\mathrm{Au}$ at high pressure. We suggest that the occurence of high-temperature superconductivity in electrides requires high-symmetry structures with hydrogenlike cages, an electron acceptor element to balance charges, and isolated IAEs coupled with medium-frequency vibrations. The uniquely designed ${\mathrm{Li}}_{8}\mathrm{Au}$ electride has a NaCl-type ($B1$) lattice, with atomic Au and cubic ${\mathrm{Li}}_{8}$ cages as bases. Isolated IAEs are formed at the cage centers, with extra charges taken up by Au. These octahedrally coordinated IAEs have a $p$-orbital-like attribute and are strongly coupled with atomic vibrations in the ${\mathrm{Li}}_{8}$ cages. The strong EPC in ${\mathrm{Li}}_{8}\mathrm{Au}$ results in a calculated ${T}_{c}$ of 73.1 K at 250 GPa, which is the highest ${T}_{c}$ reported to date for all the electrides. A slight substitutional Pt doping can enhance the ${T}_{c}$ of ${\mathrm{Li}}_{8}\mathrm{Au}$ to exceed liquid nitrogen temperature.

Effect of time Pressure on Dynamic Visual Search Performance

The laryngeal mask airway (LMA) is a large foreign body that exerts pressure on the pharyngeal mucosa, which may lead to throat discomfort. To determine whether intracuff pressures are associated with such discomfort, a randomized, double-blind study was performed to determine the effect of high versus low intracuff pressures. Seventy healthy women were randomly allocated to two groups with different LMA intracuff pressures: 30 mmHg (low pressure) or 180 mmHg (high pressure). Pressures were controlled with a microprocessor-controlled monitor. Insertion of the LMA was performed by one investigator and facilitated with propofol and verified fiberoptically. Anesthesia was maintained with enflurane and nitrous oxide. The LMAs were removed while the patients were still asleep. Patients assessed their laryngopharyngeal complaints (sore throat, dysphagia, hoarseness) at 8, 24, and 48 h after operation on a 101-point numerical rating scale. No significant difference was found in the overall incidence of complaints between both groups (low pressure: 50%; high pressure: 42%). On the day of surgery, dysphagia (38%) was more frequent than sore throat (16%) or hoarseness (6%) (P < 0.05) within the high-pressure group. In the low-pressure group, the incidence of these complaints was not significantly different (33%, 20%, and 23%, respectively). On the following day, dysphagia was still present in 20% of the women in both groups, and other symptoms comprised 10% or less of the reported complaints. Differences in LMA intracuff pressures did not influence either the incidence or severity of laryngopharyngeal complaints.

The importance of cardioplegic infusion pressure in neonatal myocardial protection

Deployable aeroshells offer the promise of achieving larger aeroshell surface areas for entry vehicles than otherwise attainable without deployment. With the larger surface area comes the ability to decelerate high-mass entry vehicles at relatively low ballistic coefficients. However, for an aeroshell to perform even at the low ballistic coefficients attainable with deployable aeroshells, a flexible thermal protection system (TPS) is required that is capable of surviving reasonably high heat flux and durable enough to survive the rigors of construction handling, high density packing, deployment, aerodynamic loading and aerothermal heating. The Program for the Advancement of Inflatable Decelerators for Atmospheric Entry (PAIDAE) is tasked with developing the technologies required to increase the technology readiness level (TRL) of inflatable deployable aeroshells, and one of several of the technologies PAIDAE is developing for use on inflatable aeroshells is flexible TPS. Several flexible TPS layups were designed, based on commercially available materials, and tested in NASA Langley Research Center's 8 Foot High Temperature Tunnel (8ft HTT). The TPS layups were designed for, and tested at three different conditions that are representative of conditions seen in entry simulation analyses of inflatable aeroshell concepts. Two conditions were produced in a single run with a sting-mounted dual wedge test fixture. The dual wedge test fixture had one row of sample mounting locations (forward) at about half the running length of the top surface of the wedge. At about two thirds of the running length of the wedge, a second test surface drafted up at five degrees relative to the first test surface established the remaining running length of the wedge test fixture. A second row of sample mounting locations (aft) was positioned in the middle of the running length of the second test surface. Once the desired flow conditions were established in the test section the dual wedge test fixture, oriented at 5 degrees angle of attack down, was injected into the flow. In this configuration the aft sample mounting location was subjected to roughly twice the heat flux and surface pressure of the forward mounting location. The tunnel was run at two different conditions for the test series: 1) 'Low Pressure', and 2) 'High Pressure'. At 'Low Pressure' conditions the TPS layups were tested at 6W/cm2 and 11W/cm2 while at 'High Pressure' conditions the TPS layups were tested at 11W/cm2 and 20W/cm2. This paper details the test configuration of the TPS samples in the 8Ft HTT, the sample holder assembly, TPS sample layup construction, sample instrumentation, results from this testing, as well as lessons learned.

Surface chemistry under high pressure of gaseous reactants is often different from surface chemistry at low pressure. For example, many surface chemical reactions proceed readily under high pressure conditions typical of a commercial, heterogeneous catalytic reaction but appear not to proceed at low pressures(<10-4 torr), despite favorable thermodynamics. The different chemistry and, in particular, the lack of reactivity at the low pressures where ultrahigh vacuum surface science techniques are operable is known loosely as the pressure gap and casts doubt on the relevance of UHV surface chemistry to high pressure processes such as catalysis, chemical vapor deposition and etching reactions. One proposal for the origin of this pressure gap in the catalytic reactivity was the presence of a barrier to the dissociative chemisorption of at least one of the reactants [1,2]. Since it is the translational energy of the incident molecule that is important in sunnounting this barrier and not the surface temperature, the rate of the reaction is limited by the flux of incident molecules with energies above the energy of the barrier. High pressures simply increase the absolute number (not the fraction) of high energy molecules, thereby increasing the reaction rate sufficiently for the products to be detected. This hypothesis was verified by the demonstration of the translational activation of C14 on Ni(111) and the ensuing favorable comparison between the rate constants for C14 dissociation calculated from the low pressure dissociation probability measurements and the rates as measured under high pressure conditions [3-5]. The agreement between the low and high pressure experiments carried out in different laboratories formly establishes

Mechanisms that underlie autoregulation in the newborn vasculature are unclear. Here we tested the hypothesis that in newborn porcine cerebral arteries intravascular pressure elevates wall tension, leading to an increase in intracellular calcium concentration ([Ca2+]i) and a constriction that is opposed by pressure-induced K+ channel activation. Incremental step (20 mmHg) elevations in intravascular pressure between 10 and 90 mmHg induced an immediate transient elevation in arterial wall [Ca2+]i and a short-lived constriction that was followed by a smaller steady-state [Ca2+]i elevation and sustained constriction. Pressures between 10 and 90 mmHg increased steady-state arterial wall [Ca2+]i between approximately 142 and 299 nM and myogenic (defined as passive-active) tension between 25 and 437 dyn/cm. The relationship between pressure and myogenic tension was strongly Ca2+ dependent until forced dilation. At low pressure, 60 mM K+ induced a steady-state elevation in arterial wall [Ca2+]i and a constriction. Nimodipine, a voltage-dependent Ca2+ channel blocker, and removal of extracellular Ca2+ similarly dilated arteries at low or high pressures. 4-Aminopyridine, a voltage-dependent K+ (Kv) channel blocker, induced significantly larger constrictions at high pressure, when compared with those at low pressure. Although selective Ca2+-activated K+ (KCa) channel blockers and intracellular Ca2+ release inhibitors induced only small constrictions at low and high pressures, a low concentration of caffeine (1 microM), a ryanodine-sensitive Ca2+ release (RyR) channel activator, increased KCa channel activity and induced dilation. These data suggest that in newborn cerebral arteries, intravascular pressure elevates wall tension, leading to voltage-dependent Ca2+ channel activation, an increase in wall [Ca2+]i and Ca2+-dependent constriction. In addition, pressure strongly activates Kv channels that opposes constriction but only weakly activates KCa channels.

An abnormally high pressure formation caused the loss of a number of Dukhan Khuff Gas (DKG) wells. The Sudair formation has always been considered normally pressured throughout the Dukhan Khuff gas field area. However, this case study supports the author's hypothesis that, contrary to that belief, Sudair can be abnormally pressured. Two DKG wells A and B were the subject of this case study. These wells experienced loss of integrity due to high annuli pressures and were recently worked over. The author's abnormally high pressure zone hypothesis is based on actual real data from both of these wells. DKG wells were drilled more than thirty years ago. All 28 wells were drilled through the Sudair formation without any pressure or well control issues. However, at some point in time, most of these wells developed annulus pressure in one or more of their annuli. How did that happen? To answer this question, the author searched other operator's experiences in the area. The search pointed out that the Sudair formation is not always normally pressured; it can also be abnormally pressured. We have seen reports of Sudair high formation pressure associated with high rate salt water flow, high rate gas flow and in occasions very low rate salt water flow. While the high rate flows are detectable, it's the very low rate high pressure salt water flow that is almost impossible to detect. Another finding is that the Sudair formation pressures are neither equal nor uniform over a large area but rather different and localized. What could we have done differently thirty-five years ago? The answer is simply no thing because we did not have the knowledge and knowhow of today. However, there are lessons to be learnt, t's to be crossed and i's to be dotted. Introduction Dukhan Khuff is a non associated high pressure gas reservoir. The field was developed in the late 1970s to supply fuel gas to the power generation plants. Because of the high pressure, Khuff Gas wells were designed and constructed according to the highest applicable standard at the time. However, most of these wells developed annulus pressure in one or more of their annuli. DKG wells crossed a number of oil and gas bearing formations that made it almost impossible to finger print the effluents that are flowing from the different annuli. Also, the experienced annuli pressures were, in most cases, within the normal range. Hence, the source of the annuli pressures remained a mystery. The occurrence of a very high sustainable tubing casing annulus (TCA) pressure in DKG-well A prompted us to search for the source of the noted unusual high pressure. Events from the well history as well as pressure data obtained during its workover supports our belief that an abnormally high pressure formation was the cause of the experienced high annulus pressure. While the exact formation bearing the high pressure had not yet been identified its properties and characteristics have become partially known. Our second case study DKG-well B is a recently drilled well. As a result of high annulus pressure, the well developed integrity issues immediately after it was put on production. During the workover to reinstate the well's integrity it became clear that the Sudair formation is the likely source of the high annulus pressure. This case study is a summary of the events that led to the discovery of the culprit high pressure zone. What's next? Now that we know what has caused the loss of integrity of a number of DKG wells. What we present here are other operators' experiences with Sudair formation and what have they done to predict and overcome its pressure.

Spacecraft operate in complex space environments filled with a variety of natural or anthropogenic particles and fields, which may trigger outgassing breakdown on their surfaces and thus lead to spacecraft failures in orbit. The physical process of outgassing breakdown in the atmosphere is more complex than in vacuum, which requires the consideration of electron–neutral collisions and electron attachment effects in addition to field emission and secondary electron multiplication. In this article, based on particle-in-cell (PIC), a 2-D simulation model of electromagnetically irradiated metal-aluminum film under atmospheric conditions is established to simulate the outgassing breakdown process in oxygen and air, and to analyze the influence laws of gas density, gas composition, microwave field strength, and electron attachment effect on the breakdown. The results show that gas breakdown is related to the background gas composition, and breakdown is more likely to occur in an oxygen environment than in air; the same kind of gas shows different breakdown formation time patterns at low and high pressures. At low pressure, the breakdown time is rapidly shortened with the increase in air pressure, and at high pressure, the breakdown time increases with the increase in air pressure; the electron attachment has an inhibitory effect on the gas breakdown at high air pressure.

The assessment of weather conditions on days with registered calls for emergency medical service (EMS) was made with the use of weather charts at the level of 850hPa, 00 UTC provided by the German Weather Service (www.wetterzentrale.de/topkarten/tkfaxbraar.htm). Synoptic situations on days with registered calls for EMS were categorized into 13 weather types according to the German Weather Service. This paper analyses the number of calls for EMS recorded on individual days in Stargard Szczecinski province in the period of 2008-2011 to people suffering from coronary heart disease, including myocardial infarction, mental disturbances (mainly schizophrenia), epilepsy, stroke, arterial hypertension, asthma and emergency-related ambulance trips as well as death. The number of calls registered in Stargard Szczecinski province in the period of 2008-2011 amounted to more than 41 thousand, and the daily number ranged from 13 to 50 – the highest in March and January, lowest in September and October. From the analysed 13 weather types the following types were most predominant on days with calls for EMS: the centre of low pressure area (type 6), cold air advection in the retral part of low pressure area (type 7), and lingering centre of high pressure area (type 1, 2). 70-80% of the analysed days in a year were characterised by low pressure system and weather types connected with it: 4 (warm aid advection in the front part of low pressure area), 5 (warm sector of low pressure area), 6 (the centre of low pressure area), 7 (cold air advection in the retral part of low pressure area); and high pressure system and weather types: 1 (high pressure centre – no thermal inversions), 2 (high pressure centre – thermal inversions), 11 (cold high pressure area), 12 (warm sector of high pressure). From the remaining 5 types of weather (3, 8, 9, 10, 13) occurring on days with calls for EMS, the following weather types were predominant: type 3 (air slips at the edge of high pressure area) – 10.1%, followed by type 8 (waving front zone) – 9.4%. Depending on the type of illness, the sensitivity of patients to changing meteorological conditions, expressed by the number of calls for EMS, varied during a year. People suffering from asthma and COPD required EMS help in summer on days with low pressure systems – 64.7%, and in winter during lingering high pressure areas – 33.3%. Epileptic seizures were more common in summer during the transition of low pressure systems – 63%, and in autumn during high pressure systems – 20% of days under study. The frequency of calls for EMS to people suffering from arterial hypertension was the highest in autumn and winter – approximately 57% each, during transition of low pressure areas, and in winter during lingering high pressure – 25.4%.

The preparation of graphene with high quality serves as a prerequisite for its usage. Traditional methods of graphene production, represented by liquid-phase exfoliation and chemical vapor depositi...

Abstract. The aims of this study were to assess the predictive role of coping-related variables (CRV) on cardiac vagal activity (derived from heart rate variability), and to investigate the influence of CRV (and cardiac vagal activity) on prone rifle shooting performance under low pressure (LP) and high pressure (HP) conditions. Participants ( n = 38) competed in a shooting task under LP and HP. Cardiac vagal activity measurements were taken at baseline, task, and recovery for 5 min, alongside ratings of stress via a visual analogue scale. Upon task conclusion, self-report measures of motivation, stress appraisal, attention, perceived pressure, and trait CRV questionnaires (Decision-Specific Reinvestment Scale [DSRS], Movement-Specific Reinvestment Scale [MSRS], and Trait Emotional Intelligence Questionnaire [TEIQue]) were completed. Results indicated that task cardiac vagal activity was predicted by resting cardiac vagal activity and self-control in HP and LP. Post-task cardiac vagal activity was predicted by resting cardiac vagal activity in both conditions with the addition of a trait and state CRV in HP. Cardiac vagal reactivity, the change from resting to task, was predicted by resting cardiac vagal activity and self-control in LP and HP. Cardiac vagal recovery, the change from task to post-task, was predicted by a trait CRV in HP. Shooting performance was predicted by experience and cardiac vagal activity in LP and cardiac vagal activity and a trait in HP. Findings suggest both CRV and cardiac vagal activity influence cardiac vagal activity throughout a pressure task. Additionally, shooting performance directly influences cardiac vagal recovery.

Background. In recent years the deterioration of the demographic situation has been noted in most countries of the world that is due to the steady increase in population of arterial hypertension and the aging of the population. According to the statistical forecast of the UN by 2025, the number of people over 60 will exceed 1 billion which is 15% of the entire global population. In Ukraine, according to epidemiological studies, the prevalence of hypertension among circulatory system diseases in adults (18 years and older) is 46.8% and almost half of patients with circulatory system diseases have elevated blood pressure. In patients aged 65 years and older, the prevalence of hypertension varies in the range of 53-72%. It has long been proven that the risk of cardiovascular and cerebrovascular complications in hypertensive patients depends not only on the absolute blood pressure level but also on fluctuations in blood pressure over different periods that is blood pressure variability. Blood pressure is not a static parameter but rather undergoes continuous fluctuations over time due to the interaction between environmental factors and behaviour on the one hand and the internal regulatory mechanisms of the cardiovascular system on the other hand. Elevated blood pressure may indicate cardiovascular dysregulation and itself may be a cardiovascular risk factor associated with increased all-cause mortality and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease and incidence of dementia. Aim. The study aimed to improve the system of prevention and diagnosis of elderly and senior hypertensive patients at the ambulatory-polyclinic stage due to the study of the contribution of blood pressure variability. Materials and methods. The group of examinees was formed taking into account 27 elderly and senile hypertensive patients including those combined with coronary artery disease. For this purpose, ambulatory blood pressure monitoring was used. Results. Systolic blood pressure variability (SD) in hypertensive patients was higher than in the control group (p&lt;0.001). So, during the study, SD was 17.9±7.1 mm Hg. while in the control group 12.1±2.6 mm Hg. The frequency of high blood pressure variability detection in elderly and senile hypertensive patients was 51.9% (n=14). High blood pressure variability compared to low blood pressure variability and control was associated with a more pronounced systolic blood pressure variability (during the active monitoring period), and it was equalled 23.7±5.2 mm Hg compared to 14.8±6.5 mm Hg (p&lt;0.001) and 12.1±2.6 mm Hg. (p&lt;0.001). In elderly and senile hypertensive patients with high and low blood pressure variability, the non-dipper group prevailed over the dipper group in the structure of daily blood pressure rhythm (71.4% vs. 28.6% and 84.6% vs. 15.4% respectively). According to the ambulatory blood pressure monitoring data high blood pressure variability group compared to low blood pressure variability and controls was characterised by higher average values of the number of blood pressure indicators. In the group of high blood pressure variability patients, the average daily systolic blood pressure exceeded the control value by 10% (р&lt;0.05). The daily index of systolic blood pressure in the group of high blood pressure variability patients was 111% higher than in patients with low blood pressure variability (p&lt;0.05). The daily index of diastolic blood pressure in the group of high blood pressure variability patients was 140% higher than in patients with low blood pressure variability (p&lt;0.05). The daily index of average blood pressure in the group of high blood pressure variability patients was 191% higher than in patients with low blood pressure variability (p&lt;0.01). Conclusions. 1. High blood pressure variability has occurred in 16 out of 27 (51.9%) hypertensive elderly and senile patients. 2. The non-dipper group has predominated in the structure of blood pressure diurnal rhythm in elderly and senile hypertensive patients with high and low blood pressure variability patients. _________________________________________________________________________________________ Keywords: arterial hypertension; essential hypertension; blood pressure variability; high blood pressure variability; low blood pressure variability; elderly and senile hypertensive patients