scholarly journals Performance characterization of polycrystalline silicon photovoltaic modules installed in Kumasi, Ghana

2021 ◽  
Vol 40 (3) ◽  
pp. 461-471
Author(s):  
G. Takyi
Keyword(s):  
Temperature Difference ◽  
Polycrystalline Silicon ◽  
Hot Spot ◽  
Standard Test ◽  
Power Performance ◽  
Field Exposure ◽  
Non Invasive ◽  
Higher Temperature ◽  
The Individual ◽  
Voltage Performance

The focus of this study is on the assessment of the performance of 14 polycrystalline silicon PV modules installed in Kumasi, Ghana after 22 years of field exposure. Visual inspection was carried out to ascertain any observable defects. Current-Voltage performance data was taken using a non-invasive characterization technique able to predict performance at standard test conditions (using TRI-KA and TRI-SEN) followed by Infrared (IR) Imaging tests. The results of the I-V tests showed average Pmax degradation rate of 1.38%/yr for all 14 modules. This is higher than the acceptable limit of (0.7–1.0%/year). In terms of the individual modules, M1 recorded the worst Pmax rate of degradation of 1.74%/yr, and the lowest values for efficiency and fill factor. This is consistent with the IR images and temperature difference that were recorded in the IR tests. A higher temperature difference of 25°C was recorded indicating the presence of a hot spot and a defective cell which was confirmed by the hue white colour observed in the IR test. Power Performance Factor (PPF) range of 61.8–76.5% was recorded which is below the limit of 80% often quoted in warranty statements. The drops in PPF indicate that the modules have degraded.

scholarly journals Urinary Cytokines Reflect Renal Inflammation in Acute Tubulointerstitial Nephritis: A Multiplex Bead-Based Assay Assessment

2021 ◽  
Vol 10 (13) ◽  
pp. 2986
Author(s):  
Laura Martinez Valenzuela ◽  
Juliana Draibe ◽  
Oriol Bestard ◽  
Xavier Fulladosa ◽  
Francisco Gómez-Preciado ◽  
...  
Keyword(s):  
Tubulointerstitial Nephritis ◽  
Urinary Concentration ◽  
Blood Eosinophil ◽  
Acute Tubulointerstitial Nephritis ◽  
Luminex Assay ◽  
Non Invasive ◽  
Urinary Levels ◽  
Histological Data ◽  
The Individual ◽  
Multiplex Bead

Background: Acute tubulointerstitial nephritis (ATIN) diagnosis lays on histological assessment through a kidney biopsy, given the absence of accurate non-invasive biomarkers. The aim of this study was to evaluate the accuracy of different urinary inflammation-related cytokines for the diagnostic of ATIN and its distinction from acute tubular necrosis (ATN). Methods: We included 33 patients (ATIN (n = 21), ATN (n = 12)), and 6 healthy controls (HC). We determined the urinary levels of 10 inflammation-related cytokines using a multiplex bead-based Luminex assay at the time of biopsy and after therapy, and registered main clinical, analytical and histological data. Results: At the time of biopsy, urinary levels of I-TAC/CXCL11, CXCL10, IL-6, TNFα and MCP-1 were significantly higher in ATIN compared to HC. A positive correlation between the extent of the tubulointerstitial cellular infiltrates in kidney biopsies and the urinary concentration of I-TAC/CXCL11, MIG/CXCL9, CXCL10, IL17, IFNα, MCP1 and EGF was observed. Notably, I-TAC/CXCL11, IL-6 and MCP-1 were significantly higher in ATIN than in ATN, with I-TAC/CXCL11 as the best discriminative classifier AUC (0.77, 95% CI 0.57–0.95, p = 0.02). A combinatory model of these three urinary cytokines increased the accuracy in the distinction of ATIN/ATN compared to the individual biomarkers. The best model resulted when combining the three cytokines with blood eosinophil and urinary leukocyte counts (LR = 9.76). Follow-up samples from 11ATIN patients showed a significant decrease in I-TAC/CXCL11, MIG/CXCL9 and CXCL10 levels. Conclusions: Urinary I-TAC/CXCL11, CXCL10, IL6 and MCP-1 levels accurately distinguish patients developing ATIN from ATN and healthy individuals and may serve as novel non-invasive biomarkers in this disease.

Polycrystalline Silicon Gettering Layers with Controlled Residual Stress

2013 ◽  
Vol 205-206 ◽  
pp. 284-289 ◽  
Author(s):  
David Lysáček ◽  
Petr Kostelník ◽  
Petr Pánek
Keyword(s):  
Residual Stress ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Opposite Sign ◽  
Chemical Vapor ◽  
Pressure Chemical ◽  
Novel Method ◽  
The Individual ◽  
Scanning Electron

We report on a novel method of low pressure chemical vapor deposition of polycrystalline silicon layers used for external gettering in silicon substrate for semiconductor applications. The proposed method allowed us to produce layers of polycrystalline silicon with pre-determined residual stress. The method is based on the deposition of a multilayer system formed by two layers. The first layer is intentionally designed to have tensile stress while the second layer has compressive stress. Opposite sign of the residual stresses of the individual layers enables to pre-determine the residual stress of the gettering stack. We used scanning electron microscopy for structural characterization of the layers and intentional contamination for demonstration of the gettering properties. Residual stress of the layers was calculated from the wafer curvature.

HEART RATE VARIABILITY RELATED TO N95 RESPIRATOR USE IN INTERNS DURING COVID-19 PANDEMIC

2021 ◽  
pp. 69-70
Author(s):  
Pakanati Sujana ◽  
Venkata Mahesh Gandhavalla ◽  
K. Prabhakara Rao
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Low Frequency ◽  
Protective Equipment ◽  
Short Term ◽  
Non Invasive ◽  
Critical Components ◽  
The Individual ◽  
N95 Respirators ◽  
Respiratory Droplets

Introduction: COVID19 is caused by SARS-CoV-2 which is primarily transmitted through respiratory droplets and contact routes. WHO recommended the use of personal protective equipment (PPE) for prevention and N95 respirators are critical components of PPE. Breathing through N95 respirator will impart stress in the individual and that can be assessed by heart rate variability (HRV). HRV measures the variation in time between each heartbeat controlled by autonomic nervous system (ANS), which is a non invasive reliable index to identify the ANS imbalances. Aims And Objectives: This study is aimed at assessing the HRV of Interns working in COVID19 wards using N95 respirators. Methodology: This study included 100 interns in whom short term HRV was recorded using the standard protocol. Lead II of ECG was recorded using AD instruments (ADI) 8channel polygraph and HRV was analysed using Labchart 8pro software. The recordings were taken before and 1hour after wearing N95 respirator. Results: Overall HRV (SDRR) was found to decrease signicantly after wearing N95 respirator for 1hr (p=0.000). Similarly, indices representing the parasympathetic component ( RMSSD and HF ) were also found to decrease signicantly with the use of N95 respirator. Low frequency (LF) power and LF/HF ratio increased signicantly with N95 respirator use (p=0.000). Conclusion: We conclude that using N95 respirator increased sympathetic activity reecting decreased HRV in our subjects Hence we recommend that it is better to change the duty pattern for interns.

A Psycho-Pedagogical Framework for Multi-Adaptive Educational Games

2011 ◽  
Vol 1 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Michael D. Kickmeier-Rust ◽  
Elke Mattheiss ◽  
Christina Steiner ◽  
Dietrich Albert
Keyword(s):  
Game Design ◽  
Educational Games ◽  
Educational Game ◽  
Key Factors ◽  
Embedded Assessment ◽  
Non Invasive ◽  
Motivational States ◽  
Individual Support ◽  
Learning Game ◽  
The Individual

One of the trump cards of digital educational games is their enormous intrinsic motivational potential. Although learning game design is often understood on a one-fits-all level, the actual motivational strength of an educational game strongly depends on the individual learners, their very specific goals, preferences, abilities, strength and weakness, personality, and experiences with gaming. Considering motivation being a fragile and constantly changing state, it is important to continuously assess learning and gaming processes and the oscillations of motivation and immersion within a game. With this premise in mind, the authors developed a psycho-pedagogical approach to a non-invasive embedded assessment of motivational states and learning progress, feeding into a dynamic, ontology-driven learner (and gamer) model. To evaluate the approach, the demonstrator games were subject to intensive quantitative and qualitative experimental research. Results show that a meaningful personalization and an individual support are key factors of the success of learning games.

scholarly journals Ultraviolet Observations of Some Close Binary Systems by the Astronomical Netherlands Satellite-Ans

1976 ◽  
Vol 73 ◽  
pp. 213-223
Author(s):  
Chi-Chao Wu
Keyword(s):  
Binary Systems ◽  
Hot Spot ◽  
Close Binary ◽  
Spectral Energy ◽  
Dwarf Novae ◽  
Energy Distributions ◽  
Primary Star ◽  
Higher Temperature ◽  
Far Ultraviolet ◽  
Ultraviolet Observations

Observations of δ Pic, a β Lyr type of eclipsing binary and seven dwarf novae are reported. The ultraviolet light curves of δ Pic indicate the accumulation of matter at the triangular Lagrangian points L4 and L5, the presence of a hot spot and a higher temperature for the primary star. The implication is that the cooler secondary fills its Roche lobe and is transfering mass to the primary; mass loss to the circumstellar space and possibly to the system may also be appreciable. The temperatures of dwarf novae are derived by comparing their ultraviolet spectral energy distributions with those for normal stars of luminosity classes IV and V. Piecing together observations for different objects, the SSCyg systems have temperatures of 28 500 K, 10 000 K and 9500 K, respectively, when they are at minimum, immediately before outburst and at the beginning of rise to maximum. At maximum, the temperature is 22 500 K or 17 300 K depending on the interstellar reddening correction for AR And. Immediately before outburst, there is a large excess of flux in the far ultraviolet as indicated by the large value of the ratio of flux at 1550 Å to that at 1800 Å. The observations of Z Cam during standstill gives a temperature of 14 900 K. No excess of flux in the far ultraviolet was observed during the maximum of AR And and the standstill of Z Cam.

A Psycho-Pedagogical Framework for Multi-Adaptive Educational Games

2013 ◽  
pp. 103-117 ◽  
Author(s):  
Michael D. Kickmeier-Rust ◽  
Elke Mattheiss ◽  
Christina Steiner ◽  
Dietrich Albert
Keyword(s):  
Game Design ◽  
Educational Games ◽  
Educational Game ◽  
Key Factors ◽  
Embedded Assessment ◽  
Non Invasive ◽  
Motivational States ◽  
Individual Support ◽  
Learning Game ◽  
The Individual

One of the trump cards of digital educational games is their enormous intrinsic motivational potential. Although learning game design is often understood on a one-fits-all level, the actual motivational strength of an educational game strongly depends on the individual learners, their very specific goals, preferences, abilities, strength and weakness, personality, and experiences with gaming. Considering motivation being a fragile and constantly changing state, it is important to continuously assess learning and gaming processes and the oscillations of motivation and immersion within a game. With this premise in mind, the authors developed a psycho-pedagogical approach to a non-invasive embedded assessment of motivational states and learning progress, feeding into a dynamic, ontology-driven learner (and gamer) model. To evaluate the approach, the demonstrator games were subject to intensive quantitative and qualitative experimental research. Results show that a meaningful personalization and an individual support are key factors of the success of learning games.

Breathlessness and other respiratory symptoms in palliative care

2021 ◽  
pp. 589-603
Author(s):  
Miriam J. Johnson ◽  
David C. Currow
Keyword(s):  
Palliative Care ◽  
Perceptual Experience ◽  
Coping Style ◽  
Help Seeking ◽  
Evidence Base ◽  
Non Invasive ◽  
Non Invasive Ventilation ◽  
Help Seeking Behaviour ◽  
The Individual ◽  
Underlying Pathophysiology

Breathlessness is prevalent among palliative care patients with intensity likely to increase as death approaches for many people. There are two main patterns of breathlessness—episodic breathlessness and constant breathlessness—and three separate qualities of breathlessness—air hunger, work or effort, and tightness. Chronic breathlessness is defined as disabling breathlessness despite optimal treatment of the underlying pathophysiology. The measurement of breathlessness includes three domains: sensory-perceptual experience, affective distress, and symptom impact. The management of breathlessness includes specific disease management, non-pharmacological interventions, pharmacological therapies, and, in a very small proportion of people, palliative non-invasive ventilation. A full assessment of the widespread effects of chronic breathlessness on the individual including coping style and help-seeking behaviour is important to tailor interventions. Interventions focused on the breathlessness can be based on a ‘Breathing, Thinking, Functioning’ clinical framework. Oral, low-dose morphine in steady state remains the pharmacological treatment with the strongest evidence base.

Preliminary design and testing of neck chamber device for baroreflex sensitivity assessment

2020 ◽  
Vol 6 (4) ◽  
pp. 132-142
Author(s):  
Pratik V Paliwal ◽  
Prathamesh H Kamble ◽  
K A Desai ◽  
Rajesh Sharma ◽  
Anish Singhal
Keyword(s):  
Standard Test ◽  
Design Development ◽  
Test Protocol ◽  
Non Invasive ◽  
Carotid Baroreceptor ◽  
Sensitivity Assessment ◽  
Neck Chamber ◽  
Design And Testing ◽  
Opening Up ◽  
Stimulation Of

This paper presents the design, development and testing of a novel neck chamber device for non-invasive stimulation of an individual carotid baroreceptor in a graded manner. The proposed neck chamber device is a strap-free design that avoids discomfort during testing due to tight seal generated by the neck collar design, and facilitates unilateral testing and targeted assessment without stimulating other neck baroreceptors. The device consists of two independent components to achieve these requirements: an outer suction mechanism and an inner chamber. The outer mechanism consists of multiple suction cups to grip the device over the human neck, while the inner chamber creates controlled positive and negative pressure for stimulation of baroreceptors using a pump. The indigenously developed device was employed for the testing by providing neck chamber stimulation in discrete steps of –20 mm Hg, –40 mm Hg, −60 mm Hg, 0 mm Hg, 20 mm Hg, 40 mm Hg and 60 mm Hg with the gap of 60 s between each stimulation as per the standard test protocol of autonomic function test. The changes in heart rate and RR interval were recorded to determine the baroreceptor gain using the logistic equation derivative and gain curve plot. The results of the present study show that the estimated baroreceptor gain is –0.109±0.04, which is consistent with the previous studies conducted using neck collar devices. The testing results showed that the desired objectives are achieved successfully by the prototype device, opening up the possibility of its use for the treatment of resistant hypertension.

A Handheld Noninvasive Sensing Method for the Measurement of Compartment Pressures

2013 ◽  
Author(s):  
C. Flegel ◽  
K. Singal ◽  
R. Rajamani
Keyword(s):  
Compartment Syndrome ◽  
Fluid Pressure ◽  
Magnetic Field Measurement ◽  
In Vitro Test ◽  
Non Invasive ◽  
Fluid Compartment ◽  
Combat Casualty ◽  
The Individual ◽  
Compartment Pressures

Compartment syndrome is a major concern in cases of extremity trauma, which occur in over 70% of military combat casualty. Without treatment, compartment syndrome can lead to paralysis, loss of limb, or death. This paper focuses on the development of a handheld sensor that can be used for the non-invasive diagnosis of compartment syndrome. Analytical development of the sensing principle is first presented in which a relation is obtained between the pressure in a fluid compartment and the stiffness experienced by a handheld probe pushing on the compartment. Then a handheld sensor that can measure stiffness of an object without requiring the use of any inertial reference is presented. The handheld sensor consists of an array of three miniature force-sensing spring loaded pistons placed together on a probe. The center spring is chosen to be significantly stiffer than the side springs. The ratio of forces between the stiff and soft springs is proportional to the stiffness of the soft object against which the probe is pushed. Small mm-sized magnets on the pistons and magnetic field measurement chips are used to measure the forces in the individual pistons. Experimental results are presented using an in-vitro test rig that replicates a fluid pressure compartment. The sensor is shown to measure pressure accurately with a resolution of 0.1 psi over the range 0.75 psi to 2.5 psi.

scholarly journals Analyzing 24-Hour Blood Pressure Measurements with a Novel Cuffless Pulse Transit Time Device in Clinical Practice—Does the Software for Heartbeat Detection Matter?

Diagnostics ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 361
Author(s):  
Leo Kilian ◽  
Philipp Krisai ◽  
Thenral Socrates ◽  
Christian Arranto ◽  
Otmar Pfister ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Transit Time ◽  
Pulse Transit Time ◽  
Population Level ◽  
Raw Data ◽  
Invasive Blood Pressure ◽  
Individual Level ◽  
Non Invasive ◽  
The Individual ◽  
The Impact

Background: The Somnotouch-Non-Invasive-Blood-Pressure (NIBP) device delivers raw data consisting of electrocardiography and photoplethysmography for estimating blood pressure (BP) over 24 h using pulse-transit-time. The study’s aim was to analyze the impact on 24-hour BP results when processing raw data by two different software solutions delivered with the device. Methods: We used data from 234 participants. The Somnotouch-NIBP measurements were analyzed using the Domino-light and Schiller software and compared. BP values differing >5 mmHg were regarded as relevant and explored for their impact on BP classification (normotension vs. hypertension). Results: Mean (±standard deviation) absolute systolic/diastolic differences for 24-hour mean BP were 1.5 (±1.7)/1.1 (±1.3) mm Hg. Besides awake systolic BP (p = 0.022), there were no statistically significant differences in systolic/diastolic 24-hour mean, awake, and asleep BP. Twenty four-hour mean BP agreement (number (%)) between the software solutions within 5, 10, and 15 mmHg were 222 (94.8%), 231 (98.7%), 234 (100%) for systolic and 228 (97.4%), 232 (99.1%), 233 (99.5%) for diastolic measurements, respectively. A BP difference of >5 mmHg was present in 24 (10.3%) participants leading to discordant classification in 4–17%. Conclusion: By comparing the two software solutions, differences in BP are negligible at the population level. However, at the individual level there are, in a minority of cases, differences that lead to different BP classifications, which can influence the therapeutic decision.

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