Rolling Bearings Lubricated With Refrigerant

Oil-free systems gain increased popularity in the chiller industry. This technology is often related to reduced maintenance, higher system efficiency and smaller environmental footprint. In refrigeration compressors which use oil for the lubrication it is impossible to avoid mixing of refrigerant and oil in the system. The system efficiency is affected by the contamination of the refrigerant by oil. One possibility to operate a compressor of a chiller without oil is the pure refrigerant lubrication (PRL) bearing technology. With this technology the traditional oil lubrication system can be removed completely and the bearings are lubricated only with refrigerant. This removes the challenges related to mixtures of fluids - on the chiller performance side (efficiency reduction due to oil contamination of the working fluid) as well as on the lubrication side (lubricant diluted by refrigerant). The challenge which pure refrigerant lubrication poses to rolling bearings was overcome by a special bearing development. Energy efficiency and total cost of ownership are major drivers of the industry. Therefore, accurate predictions of bearing power losses became a fundamental component of the bearing performance rating. For bearings operating in refrigerant environment, friction is even more important, since the heat generation affects the thermodynamics of the refrigerant, and can lead to refrigerant evaporation and starvation. A special bearing test rig has been developed, which allows the investigation of the bearing performance under pure refrigerant lubrication conditions. Its main components are the hermetic bearing test head and the refrigerant supply system. The test rig was designed to withstand the conditions present in refrigerant environments and enables the investigation of refrigerant condition and injection properties of typical bearing operating conditions. The refrigerant is pumped, filtered and conditioned in the lubrication circuit before it is injected into the bearing to provide cooling and lubrication. The bearings inside the stainless steel housing can be subjected to various loads and rotational speeds. The refrigerant properties such as film building ability, density and the boundary friction coefficient as well as possible evaporation influence the bearing friction characteristics. With the test rig the influence of the thermodynamic behaviour can be analysed. The mapping of the friction behaviour under various operating conditions allows the optimisation of the injection properties. PRL bearings enable machine designs which offer excellent overall system efficiency

Investigating Spatial and Temporal Structuring of E-Region Coherent Scattering Regions Over Northern Norway

Recently, it has been shown that the Spread Spectrum Interferometric Multistatic meteor radar Observing Network radar system located in northern Norway is capable of measuring ionospheric E-region coherent scatter with spatial and temporal resolutions on the order of 1.5 km and 2 s, respectively. Four different events from June and July of 2022 are examined in the present study, where the coherent scatter measurements are used as a tracer for large-scale ionospheric phenomena such as plasma density enhancements and ionospheric electric fields. By applying a two-dimensional Fourier analysis to range-time-intensity data, we perform a multi-scale spatial and temporal investigation to determine the change in range over time of large-scale ionospheric structures (>3 km) which are compared with line-of-sight velocities of the small scale structures (∼5 m) determined from the Doppler shift of the coherent scatter. The spectral characteristics of the large-scale structures are also investigated and logarithmic spectral slopes for scale sizes of 100–10 km were found to be between −3.0 and −1.5. This agrees with much of the previous work on the spatial spectra scaling for ionospheric electric fields. This analysis aids in characterizing the source of the plasma turbulence and provides crucial information about how energy is redistributed from large to small scales in the E-region ionosphere

The Implications of Blood Transfusions for Patients With Non–ST-Segment Elevation Acute Coronary Syndromes: Results From the CRUSADE National Quality Improvement Initiative

In a large contemporary population of patients with non–ST-segment elevation acute coronary syndromes (NSTE ACS), we sought to describe blood transfusion rates (overall and in patients who did not undergo coronary artery bypass grafting [CABG]), patient characteristics and practices associated with transfusion, variation among hospitals, and in-hospital outcomes in patients receiving transfusions.The use of antithrombotic agents and invasive procedures reduces ischemic complications but increases risks for bleeding and need for blood transfusion in patients with NSTE ACS.We evaluated patient characteristics and transfusion rates in the overall population (n = 85,111) and determined outcomes and factors associated with need for transfusion in a subpopulation of patients who did not undergo CABG (n = 74,271) from 478 U.S. hospitals between January 1, 2001, and March 31, 2004.A total of 14.9% of the overall and 10.3% of the non-CABG population underwent transfusion during their hospitalization. Renal insufficiency and advanced age were strongly associated with the likelihood of transfusion. Interhospital transfusion rates varied significantly. Non-CABG patients who received transfusions had a greater risk of death (11.5% vs. 3.8%) and death or reinfarction (13.4% vs. 5.8%) than patients who did not undergo transfusion.Transfusion is common in the setting of NSTE ACS, and patients who undergo transfusion are sicker at baseline and experience a higher risk of adverse outcomes than their nontransfused counterparts. Given the wide variation in transfusion practice, further efforts to understand patient and process factors that result in bleeding and need for transfusion in NSTE ACS are needed

Integrating spirituality as a key component of patient care

Patient care frequently focuses on physical aspects of disease management, with variable attention given to spiritual needs. And yet, patients indicate that spiritual suffering adds to distress associated with illness. Spirituality, broadly defined as that which gives meaning and purpose to a person’s life and connectedness to the significant or sacred, often becomes a central issue for patients. Growing evidence demonstrates that spirituality is important in patient care. Yet healthcare professionals (HCPs) do not always feel prepared to engage with patients about spiritual issues. In this project, HCPs attended an educational session focused on using the FICA Spiritual History Tool to integrate spirituality into patient care. Later, they incorporated the tool when caring for patients participating in the study. This research (1) explored the value of including spiritual history taking in clinical practice; (2) identified facilitators and barriers to incorporating spirituality into person-centred care; and (3) determined ways in which HCPs can effectively utilize spiritual history taking. Data were collected using focus groups and chart reviews. Findings indicate positive impacts at organizational, clinical/unit, professional/personal and patient levels when HCPs include spirituality in patient care. Recommendations are offered

Brain catecholamine depletion and motor impairment in a Th knock-in mouse with type B tyrosine hydroxylase deficiency

Tyrosine hydroxylase catalyses the hydroxylation of L-tyrosine to l-DOPA, the rate- limiting step in the synthesis of catecholamines. Mutations in the TH gene encoding tyrosine hydroxylase are associated with the autosomal recessive disorder tyrosine hydroxylase deficiency, which manifests phenotypes varying from infantile parkinsonism and DOPA-responsive dystonia, also termed type A, to complex encephalopathy with perinatal onset, termed type B. We generated homozygous Th knock-in mice with the mutation Th-p.R203H, equivalent to the most recurrent human mutation associated with type B tyrosine hydroxylase deficiency (TH-p.R233H), often unresponsive to l-DOPA treatment. The Th knock-in mice showed normal survival and food intake, but hypotension, hypokinesia, reduced motor coordination, wide-based gate and catalepsy. This phenotype was associated with a gradual loss of central catecholamines and the serious manifestations of motor impairment presented diurnal fluctuation but did not improve with standard l-DOPA treatment. The mutant tyrosine hydroxylase enzyme was unstable and exhibited deficient stabilization by catecholamines, leading to decline of brain tyrosine hydroxylase-immunoreactivity in the Th knock-in mice. In fact the substantia nigra presented an almost normal level of mutant tyrosine hydroxylase protein but distinct absence of the enzyme was observed in the striatum, indicating a mutation-associated mislocalization of tyrosine hydroxylase in the nigrostriatal pathway. This hypomorphic mouse model thus provides understanding on pathomechanisms in type B tyrosine hydroxylase deficiency and a platform for the evaluation of novel therapeutics for movement disorders with loss of dopaminergic input to the striatum

Long-term outcome of displaced radial neck fractures in adulthood: 16–21 year follow-up of 5 patients treated with radial head excision

Background There have been no reports on the long-term outcome of radial neck Mason type IIIb fractures in adults