Volumetric Efficiency Improvement by Overflow in Rolling Piston Compressor

The rotary compressor with rolling piston is a widely used compressor with less clearance volume, while it is minimized from normal scale to meso or micro scale, the input and exit ports dimension is limited by port requirement and lead to a certain clearance volume, therefore, keeping or improving its volume efficiency is an important issue. Although rolling piston compressor is a kind of compact structure compressor, the existence of the clearance volume is inevitable in a compressor, the more the clearance volume, the lower the volumetric efficiency of compressor. The overflow is a method to improve the volumetric efficiency of a compressor which had been discussed in wankel compressor, in the overflowing process the clearance space with high pressure is connected directly with the space with lower pressure, mostly that is in the moment, one of the chambers in the rotary compressor is at the end of the exhaust process, and another chamber is at the sucking stage or the initial compression process. The gas pressure in the clearance volume is visibly higher than that in the compression chamber. The high-pressure gas in the clearance volume flows into the compression cylinder via a certain way; this flow considerably increases the pressure in the compression cylinder and decreases the pressure in the clearance volume. Thus, the intake and exhaust times means to be extended, and the volumetric efficiency and the cooling capacity of the compressor can be substantially enhanced. In this paper, we introduce the effect of input and exit dimensions on the volume efficiency of rolling piston compressor, and the overflow design on a rolling piston compressor that fully uses the high-pressure gas in the clearance volume, and discuss its effect on the performance of a compressor by theoretical analyses. Usually, the coefficient of performance of a vapor refrigeration cycle with the compressor overflow has a certain decrease compared with the conventional compressor, but the volumetric efficiency of the compressor with overflow and the cooling capacity of the thermodynamic cycle recesses are visibly higher than those of the conventional compressor in terms of the same operation and dimension parameters. The overflow has beneficial effect on miniaturizing the compresso

Multiple synchronous primary malignancies induced by benzene exposure: a case report

<p>Abstract</p> <p>Background</p> <p>Chronic exposure to high concentrations of benzene is usually associated with the development of haematological diseases. However, solid tumors induced by benzene exposure are less frequent.</p> <p>Case presentation</p> <p>We present an unusual case of triple synchronous primary malignancies most likely induced by occupational benzene exposure in a male patient. This spray painter was diagnosed as chronic aplastic anemia in his 21 years old after exposing to high concentration of benzene for three years. Then he was treated with glucocorticoid for four years. 40 years later, this patient developed three synchronous primary neoplasms with three different histologies including a basaloid squamous cell carcinoma of the esophagus, primary hepatocellular carcinoma, and well-differentiated squamous cell carcinoma of the gum.</p> <p>Conclusion</p> <p>This case reminds us that the occurrence of solid tumors should be monitored in workers with occupational history linked with a high concentration exposure to benzene, though it's rarely happened.</p

Empyema, acute respiratory failure, and septic shock after aspiration of a soft-shelled turtle (Pelodiscus sinensis) bone by an adult

INTRODUCTION: The common late complications of foreign body aspiration include granulation formation, obstructive pneumonia, and atelectasis. However, a foreign body-induced pleural infection is very rare, and especially when it is not iatrogenic. CASE DESCRIPTION: A 64-year-old Chinese man was admitted to our hospital with septic shock and acute respiratory failure requiring intubation and mechanical ventilation. Computed tomography revealed multiloculated pleural effusion on the whole right side and right lung atelectasis, with enhanced thickening and calcification of pleura and a foreign body in the right intermediate bronchus. The effusion appeared as a cloudy fluid consistent with pus. A bedside bronchoscopy revealed an irregular foreign body lodged in the right intermediate bronchus. The hard bone was removed and confirmed to be a soft-shelled turtle bone. A final diagnosis of foreign body-induced empyema, acute respiratory failure, and septic shock was confirmed. The patient showed good recovery after completing a course of broad-spectrum antibiotics and undergoing chest tube drainage. DISCUSSION AND EVALUATION: Although empyema has been reported previously as a rare complication of long-term retention of an aspirated foreign body, no case has been observed that was as serious as our current patient. In addition, a foreign body aspiration by a soft-shelled turtle bone was never reported before. CONCLUSIONS: For the first time, we describe the successful treatment of an adult patient presenting with empyema, accompanied by serious conditions of acute respiratory failure and septic shock induced by aspiration of a soft-shelled turtle bone. Clinicians should consider the possibility of non-iatrogenic foreign body-induced empyema with acute onset of respiratory failure, when a patient’s symptoms cannot be attributed to an alternative obvious cause

Simulation of the effect of stand-off parameter on collapse behaviours of a single cavitation bubble in jet drilling

Cavitation jet drilling has been extensively employed for the exploitation of geo-energy resources. The dynamics of cavitation bubbles in close proximity to the solid boundary have been a subject of great interest during jet drilling, as they play a crucial role in determining the cavitation performance. In present work, the dynamics of a single cavitation bubble near a solid surface is numerically investigated by using the axisymmetric Navier-Stokes equations and the volume of fluid method with considering the surface tension of gas-liquid interface, liquid viscosity and compressibility of gas in bubble. The simulated profiles are qualitatively and quantitatively consistent with the experimental images, which proves the reliability of employed numerical model. The effects of stand-off distance on the bubble profiles, bubble volume and collapse time have been analysed. Moreover, the cavitation erosion patterns towards the solid wall are also revealed for different dimensionless standoff distances. The simulation results reveal two distinct collapse patterns for the bubble profiles. The solid wall significantly impedes the shrinkage rate of the bubble, resulting in the longest collapse time when the dimensionless stand-off distance is 1.0. Three erosion patterns of cavitation bubbles towards the solid wall are observed, with the shock wave and micro-jet both contributing significantly to the damage caused by cavitation erosion. The shock wave sweeps the wall resulting in circular corrosion pits with a severely eroded centre, while the micro jet penetrates the wall leading to small spot corrosion pits.Document Type: Original articleCited as: Wu, X., Zhang, Y., Huang, H., Hui, C., Hu, Z., Li, G. Simulation of the effect of stand-off parameter on collapse behaviours of a single cavitation bubble in jet drilling. Advances in Geo-Energy Research, 2023, 8(3): 181-192. https://doi.org/10.46690/ager.2023.06.0

Characteristic Compounds Identification and Authenticity Evaluation of Heptapleurum Honey

In order to clarify the characteristic compounds and establish the authenticity evaluation method of heptapleurum honey, high-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (HPLC-Q/TOF-MS/MS) was used to qualitative and quantitative analysis of characteristic compounds in heptapleurum honey. Five compounds were identified including 4-(1'-cyclodiethyl ether-3'-butanediol)-3,5,5-trimethyl-2-cyclohexenone (Unedone B), 3,4,5-trimethoxy cinnamyl alcohol, 4-(1'2'-dihydroxy-3'epoxypropane) -3,5,5-2-cyclohexenone (Unedone C), trans, trans abscisic acid, and cis, trans abscisic acid. Notably, 3,4,5-trimethoxy cinnamyl alcohol was first found in honey, and it could be a marker of heptapleurum honey. Moreover, 10 raw heptapleurum honey samples with different geographic origins were collected to establish HPLC fingerprint. The authenticity of six commercial heptapleurum honey samples were evaluated by combining characteristic compound with HPLC fingerprint. The results demonstrated that three brands of sample were genuine pure heptapleurum honey, two brands of sample might be mixed with other honeys. A brand sample did not contain characteristic compound and were significantly different with the standard fingerprints of heptapleurum honey. It was inferred that the sample was not heptapleurum honey. This study provides theoretical reference for the authenticity evaluation of heptapleurum honey

Progress in the effect of oligosaccharide modification on gelability of egg white protein

Egg white protein is a high-quality protein with high nutritional value and a variety of functional properties. The oligosaccharides can be covalently bound to the egg white protein through the glycosylation reaction, and the functional properties of the conjugates were improved compared with the natural egg white protein. In this review, the gel mechanism of oligosaccharide-egg white protein conjugates was reviewed, and the influencing factors of oligosaccharide-modified egg albumin gels were discussed. Moreover, effects of oligosaccharides on the functional properties of egg albumins were summarized, and the processing and application of oligosaccharide-modified egg albumin were prospected

Electromagnetic properties of aluminum-based bilayers for kinetic inductance detectors

The complex conductivity of a superconducting thin film is related to the quasiparticle density, which depends on the physical temperature and can also be modified by external pair breaking with photons and phonons. This relationship forms the underlying operating principle of Kinetic Inductance Detectors (KIDs), where the detection threshold is governed by the superconducting energy gap. We investigate the electromagnetic properties of thin-film aluminum that is proximitized with either a normal metal layer of copper or a superconducting layer with a lower TC , such as iridium, in order to extend the operating range of KIDs. Using the Usadel equations along with the Nam expressions for complex conductivity, we calculate the density of states and the complex conductivity of the resulting bilayers to understand the dependence of the pair breaking threshold, surface impedance, and intrinsic quality factor of superconducting bilayers on the relative film thicknesses. The calculations and analyses provide theoretical insights in designing aluminum-based bilayer kinetic inductance detectors for detection of microwave photons and athermal phonons at the frequencies well below the pair breaking threshold of a pure aluminum film