Performance characteristic curve insensitive to feedback fluidic oscillator configurations

2013 ◽  
Vol 189 ◽  
pp. 55-60 ◽  
Author(s):  
Cong Xu ◽  
Xiangda Meng
Keyword(s):  
Performance Characteristic ◽  
Characteristic Curve ◽  
Fluidic Oscillator

Measurement of Performance Characteristics of a Piezoelectric Micro Blower

2013 ◽  
Author(s):  
Takashi Fukue ◽  
Koichi Hirose ◽  
Hirotoshi Terao
Keyword(s):  
Flow Rate ◽  
Measurement System ◽  
Performance Characteristic ◽  
Static Pressure ◽  
Characteristic Curve ◽  
Pressure Rise ◽  
Electronic Equipment ◽  
Cooling Performance ◽  
Cooling Air ◽  
The Relationship

This study conducts a measurement system of a performance of a piezoelectric micro blower. Electronic equipments such as laptop computers and cellular phones become smaller and thinner while their functions become more complex. As a result, a lot of components are mounted in an electronic enclosure and flow passages for the cooling air become narrow. This causes significant pressure drop and general cooling fans cannot supply enough cooling air. To improve cooling performance in small electronic equipment, a new air supply system which combines smaller and thinner size with a high pressure performance characteristic is needed. We focused on a novel piezoelectric micro blower. This blower can supply the airflow with high static pressure using the vibration of the piezoelectric element. This may produce a forced convection cooling with low electric power regardless of the size of electronic equipment and packaging density of electrical devices. However, to predict accurate cooling performance of the piezoelectric micro blower in thermal design, we have to obtain a correct supply flow rate of the blower because the cooling performance of forced convection is significantly dependent on the supply flow rate. Generally, an operating point of the blower, which is the operating pressure and the flow rate in electronic equipment, is the point of intersection of performance characteristic curve, which is the relationship between the blower’s pressure rise and the supply flow rate, and flow resistance curve in equipment. Therefore the measurement of the performance characteristic curve is most important. We tried to develop the measurement system of the performance characteristic curve of the piezoelectric micro blower with high accuracy. We succeeded to measure the relationship between the supply flow rate and the static pressure rise of the micro blower. Moreover, in order to clarify whether the micro blower is available for a cooling method of high-density packaging electronic equipment or not, we tried to investigate the effects of the obstruction, which is mounted in front of the blower, on the performance characteristic. Then, we confirmed whether the performance of the blower is changed by the components mounted near the blower or not.

The Role of a Decision Rule in Symptomatic Pulmonary Embolism Patients with a Non-high Probability Ventilation-perfusion Scan

1997 ◽  
Vol 78 (02) ◽  
pp. 794-798 ◽  
Author(s):  
Bowine C Michel ◽  
Philomeen M M Kuijer ◽  
Joseph McDonnell ◽  
Edwin J R van Beek ◽  
Frans F H Rutten ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Decision Rule ◽  
Predictive Value ◽  
Patient Population ◽  
High Probability ◽  
Characteristic Curve ◽  
Stepwise Logistic Regression ◽  
Pulmonary Angiogram ◽  
Symptomatic Pulmonary Embolism ◽  
Perfusion Scan

Summary Background: In order to improve the use of information contained in the medical history and physical examination in patients with suspected pulmonary embolism and a non-high probability ventilation-perfusion scan, we assessed whether a simple, quantitative decision rule could be derived for the diagnosis or exclusion of pulmonary embolism. Methods: In 140 consecutive symptomatic patients with a non- high probability ventilation-perfusion scan and an interpretable pulmonary angiogram, various clinical and lung scan items were collected prospectively and analyzed by multivariate stepwise logistic regression analysis to identify the most informative combination of items. Results: The prevalence of proven pulmonary embolism in the patient population was 27.1%. A decision rule containing the presence of wheezing, previous deep venous thrombosis, recently developed or worsened cough, body temperature above 37° C and multiple defects on the perfusion scan was constructed. For the rule the area under the Receiver Operating Characteristic curve was larger than that of the prior probability of pulmonary embolism as assessed by the physician at presentation (0.76 versus 0.59; p = 0.0097). At the cut-off point with the maximal positive predictive value 2% of the patients scored positive, at the cut-off point with the maximal negative predictive value pulmonary embolism could be excluded in 16% of the patients. Conclusions: We derived a simple decision rule containing 5 easily interpretable variables for the patient population specified. The optimal use of the rule appears to be in the exclusion of pulmonary embolism. Prospective validation of this rule is indicated to confirm its clinical utility.

The role of serum periostin in the diagnosis of asthma: A meta-analysis

2020 ◽  
Vol 41 (4) ◽  
pp. 240-247
Author(s):  
Lei Yang ◽  
Qingtao Zhao ◽  
Shuyu Wang
Keyword(s):  
Diagnostic Accuracy ◽  
Meta Analysis ◽  
Characteristic Curve ◽  
False Negative ◽  
Summary Receiver Operating Characteristic ◽  
True Negative ◽  
Negative Results ◽  
Noninvasive Biomarker ◽  
Sensitivity Specificity ◽  
Serum Periostin

Background: Serum periostin has been proposed as a noninvasive biomarker for asthma diagnosis and management. However, its accuracy for the diagnosis of asthma in different populations is not completely clear. Methods: This meta-analysis aimed to evaluate the diagnostic accuracy of periostin level in the clinical determination of asthma. Several medical literature data bases were searched for relevant studies through December 1, 2019. The numbers of patients with true-positive, false-positive, false-negative, and true-negative results for the periostin level were extracted from each individual study. We assessed the risk of bias by using Quality Assessment of Diagnostic Accuracy Studies 2. We used the meta-analysis to produce summary estimates of accuracy. Results: In total, nine studies with 1757 subjects met the inclusion criteria. The pooled estimates of sensitivity, specificity, and diagnostic odds ratios for the detection of asthma were 0.58 (95% confidence interval [CI], 0.38‐0.76), 0.86 (95% CI, 0.74‐0.93), and 8.28 (95% CI, 3.67‐18.68), respectively. The area under the summary receiver operating characteristic curve was 0.82 (95% CI, 0.79‐0.85). And significant publication bias was found in this meta‐analysis (p = 0.39). Conclusion: Serum periostin may be used for the diagnosis of asthma, with moderate diagnostic accuracy.

Proliferation-dominant high-grade astrocytoma: survival benefit associated with extensive resection of FLAIR abnormality region

2020 ◽  
Vol 132 (4) ◽  
pp. 998-1005 ◽  
Author(s):  
Haihui Jiang ◽  
Yong Cui ◽  
Xiang Liu ◽  
Xiaohui Ren ◽  
Mingxiao Li ◽  
...  
Keyword(s):  
Survival Benefit ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Characteristic Curve ◽  
Extent Of Resection ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
High Grade ◽  
Extensive Resection ◽  
High Grade Astrocytoma

OBJECTIVEThe aim of this study was to investigate the relationship between extent of resection (EOR) and survival in terms of clinical, molecular, and radiological factors in high-grade astrocytoma (HGA).METHODSClinical and radiological data from 585 cases of molecularly defined HGA were reviewed. In each case, the EOR was evaluated twice: once according to contrast-enhanced T1-weighted images (CE-T1WI) and once according to fluid attenuated inversion recovery (FLAIR) images. The ratio of the volume of the region of abnormality in CE-T1WI to that in FLAIR images (VFLAIR/VCE-T1WI) was calculated and a receiver operating characteristic curve was used to determine the optimal cutoff value for that ratio. Univariate and multivariate analyses were performed to identify the prognostic value of each factor.RESULTSBoth the EOR evaluated from CE-T1WI and the EOR evaluated from FLAIR could divide the whole cohort into 4 subgroups with different survival outcomes (p < 0.001). Cases were stratified into 2 subtypes based on VFLAIR/VCE-T1WIwith a cutoff of 10: a proliferation-dominant subtype and a diffusion-dominant subtype. Kaplan-Meier analysis showed a significant survival advantage for the proliferation-dominant subtype (p < 0.0001). The prognostic implication has been further confirmed in the Cox proportional hazards model (HR 1.105, 95% CI 1.078–1.134, p < 0.0001). The survival of patients with proliferation-dominant HGA was significantly prolonged in association with extensive resection of the FLAIR abnormality region beyond contrast-enhancing tumor (p = 0.03), while no survival benefit was observed in association with the extensive resection in the diffusion-dominant subtype (p=0.86).CONCLUSIONSVFLAIR/VCE-T1WIis an important classifier that could divide the HGA into 2 subtypes with distinct invasive features. Patients with proliferation-dominant HGA can benefit from extensive resection of the FLAIR abnormality region, which provides the theoretical basis for a personalized resection strategy.

Comparison of PROMIS Anxiety and Depression, PHQ-8, and GAD-7 to screen for anxiety and depression among patients presenting for spine surgery

2019 ◽  
Vol 30 (4) ◽  
pp. 524-531
Author(s):  
Taylor E. Purvis ◽  
Brian J. Neuman ◽  
Lee H. Riley ◽  
Richard L. Skolasky
Keyword(s):  
Major Depression ◽  
Spine Surgery ◽  
Characteristic Curve ◽  
Depression Scale ◽  
Data Driven ◽  
Anxiety And Depression ◽  
Measurement Information ◽  
Generalized Anxiety ◽  
Cut Points ◽  
Patient Reported

OBJECTIVEIn this paper, the authors demonstrate to spine surgeons the prevalence and severity of anxiety and depression among patients presenting for surgery and explore the relationships between different legacy and Patient-Reported Outcomes Measurement Information System (PROMIS) screening measures.METHODSA total of 512 adult spine surgery patients at a single institution completed the 7-item Generalized Anxiety Disorder questionnaire (GAD-7), 8-item Patient Health Questionnaire (PHQ-8) depression scale, and PROMIS Anxiety and Depression computer-adaptive tests (CATs) preoperatively. Correlation coefficients were calculated between PROMIS scores and GAD-7 and PHQ-8 scores. Published reference tables were used to determine the presence of anxiety or depression using GAD-7 and PHQ-8. Sensitivity and specificity of published guidance on the PROMIS Anxiety and Depression CATs were compared. Guidance from 3 sources was compared: published GAD-7 and PHQ-8 crosswalk tables, American Psychiatric Association scales, and expert clinical consensus. Receiver operator characteristic curves were used to determine data-driven cut-points for PROMIS Anxiety and Depression. Significance was accepted as p < 0.05.RESULTSIn 512 spine surgery patients, anxiety and depression were prevalent preoperatively (5% with any anxiety, 24% with generalized anxiety screen-positive; and 54% with any depression, 24% with probable major depression). Correlations were moderately strong between PROMIS Anxiety and GAD-7 scores (r = 0.72; p < 0.001) and between PROMIS Depression and PHQ-8 scores (r = 0.74; p < 0.001). The observed correlation of the PROMIS Depression score was greater with the PHQ-8 cognitive/affective score (r = 0.766) than with the somatic score (r = 0.601) (p < 0.001). PROMIS Anxiety and Depression CATs were able to detect the presence of generalized anxiety screen-positive (sensitivity, 86.0%; specificity, 81.6%) and of probable major depression (sensitivity, 82.3%; specificity, 81.4%). Receiver operating characteristic curve analysis demonstrated data-driven cut-points for these groups.CONCLUSIONSPROMIS Anxiety and Depression CATs are reliable tools for identifying generalized anxiety screen-positive spine surgery patients and those with probable major depression.

Performansi aktual modul photovoltaik dengan pengarah matahari

2018 ◽  
Vol 12 (2) ◽  
pp. 98 ◽  
Author(s):  
Jalaluddin . ◽  
Baharuddin Mire
Keyword(s):  
Solar Radiation ◽  
Local Time ◽  
Performance Characteristic ◽  
Electrical Energy ◽  
Photovoltaic Module ◽  
Experiment Data ◽  
Actual Performance ◽  
Pv Module ◽  
Solar Tracking ◽  
Pv Modules

Actual performance of photovoltaic module with solar tracking is presented. Solar radiation can be converted into electrical energy using photovoltaic (PV) modules. Performance of polycristalline silicon PV modules with and without solar tracking are investigated experimentally. The PV module with dimension 698 x 518 x 25 mm has maximum power and voltage is 45 Watt and 18 Volt respectively. Based on the experiment data, it is concluded that the performance of PV module with solar tracking increases in the morning and afternoon compared with that of fixed PV module. It increases about 18 % in the morning from 10:00 to 12:00 and in the afternoon from 13:30 to 14:00 (local time). This study also shows the daily performance characteristic of the two PV modules. Using PV module with solar tracking provides a better performance than fixed PV module. 

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