A STUDY ON PREVALENT FACTORS BEHIND EFFICIENCY DETERIORATION OF A TYPICAL LOW POWER SOLAR PANEL

2013 ◽  
Vol 2013 (1) ◽  
pp. 000384-000388
Author(s):  
V. Ganescu ◽  
A. Pascu
Keyword(s):  
Low Power ◽  
Operating Conditions ◽  
Extreme Temperatures ◽  
Solar Panels ◽  
Cycle Number ◽  
Solar Noon ◽  
Operation Duration ◽  
Outdoor Behavior ◽  
Duration Of Operation ◽  
Daylight Exposure

Efficiencies for a number of different low power (10W MAX) consumer grade PV solar panels were studied in this research. Outdoor behavior was contrasted with lab environment simulations. The authors focused on four parameters: extreme temperatures of operation, duration of operation per “on” cycle, number of “on – off” cycles and overall period of “on” operation for a 365 days interval. Standard environmental operating conditions were taken into account for the lab environment, where constant solar noon was simulated for 70% of the equivalent daylight exposure time. No CPV or lenses were used. Additionally, a comparison surrounding the estimated life expectancy and efficiency decrease pattern of the panels was targeted and presented in this study.

scholarly journals An Assessment of Snail-Farm Systems Based on Land Use and Farm Components

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Konstantinos Apostolou ◽  
Alexandra Staikou ◽  
Smaragda Sotiraki ◽  
Marianthi Hatziioannou
Keyword(s):  
Open Field ◽  
Geographical Location ◽  
Farming Systems ◽  
Annual Production ◽  
Categorical Variables ◽  
Mixed System ◽  
Continuous Variables ◽  
Sustainable Food ◽  
Operation Duration ◽  
Duration Of Operation

In this study, the structural and management characteristics of snail farms in Greece were analyzed to maximize sustainable food production. Objectives, such as the classification of farming systems and assessing the effects of various annual production parameters, were investigated. Data were collected (2017) via a questionnaire, and sampling was conducted in 29 snail farms dispersed in six different regions (Thrace, Central Macedonia, West Macedonia, Thessaly, Western Greece, and the Attica Islands). Descriptive statistics for continuous variables and frequencies for categorical variables were calculated. The similarity between farms was analyzed using nonmetric multidimensional scaling (nMDS). The average farm operation duration exceeded eight months and the mean annual production was 1597 kg of fresh, live snails. Results recorded five farming systems: elevated sections (7%), net-covered greenhouse (38%), a mixed system with a net-covered greenhouse (10%), open field (38%), and mixed system with an open field (7%). Snail farms differ in the type of substrate, available facilities, and equipment (60% similarity between most of the open field farms). The geographical location of a farms’ settlement affects productivity but also influences the duration of operation, especially in open field farms, due to their operation under a wide assortment of climatic types.

scholarly journals Do we have a limit for retrograde intrarenal surgery for solitary kidney stone?

2021 ◽  
Vol 93 (3) ◽  
pp. 318-322
Author(s):  
Bulent Kati ◽  
Eyyup Sabri Pelit ◽  
Mehmet Demir ◽  
Ismail Yagmur ◽  
Adem Tuncekin ◽  
...  
Keyword(s):  
Kidney Stone ◽  
Surgical Complication ◽  
Operation Time ◽  
Patient Characteristics ◽  
Solitary Kidney ◽  
Retrograde Intrarenal Surgery ◽  
Stone Size ◽  
Operation Duration ◽  
The Mean ◽  
Duration Of Operation

Objective: The management of urolithiasis in patients with a solitary kidney is challenging for urologists. This study aimed to evaluate the safety of retrograde intrarenal surgery (RIRS) in the treatment of stones in patients with solitary kidney and to reply to the question if there is any limit for this surgery. Methods: Between January 2016 and December 2019, we enrolled 52 patients who had a solitary kidney and underwent RIRS. We collected data on preoperative patient characteristics, stone dimensions, and postoperative outcomes. Stone size, duration of operation, duration of fluoroscopy, type of anesthesia, and degree of surgical complication were evaluated retrospectively. Surgeries performed in less and more than 60 minutes and with and without complications were compared. Results: A total of 52 patients with a kidney stone and a solitary kidney were evaluated. The mean stone size was 14 ± 0.4 cm and surgical success rate was 87.3%. In our study, 13 patients (24.5%) had grade 1 minor complications, and none required a blood transfusion. The mean operation time was 51.9 ± 17.3 minutes. The postoperative creatinine value increased in 6 patients. The duration of operation in the group with complications was significantly higher than that in the group without complications. In patients who underwent an operation lasting ≥ 60 minutes, stone size, fluoroscopy time, and complication rate were significantly higher than in patients who underwent an operation lasting ≤ 60 minutes. Conclusion: Our opinion is to be careful in patients with a solitary kidney with a big stone and we recommend assigning these procedure to experienced hands for not exceeding 60 minutes in one session.

scholarly journals Impact of Number of Operators and Distance to Branch Piles on Woodchipper Operation

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 598 ◽  
Author(s):  
Łukasz Warguła ◽  
Mateusz Kukla ◽  
Piotr Krawiec ◽  
Bartosz Wieczorek
Keyword(s):  
Low Power ◽  
Adaptive Systems ◽  
Operating Time ◽  
Operating Mode ◽  
Operating Conditions ◽  
Operating Condition ◽  
Time Frequency ◽  
Drive Speed ◽  
Type Machine ◽  
Volume Output

Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. This article discusses the issues related to the assessment of the application of adaptive systems similar in design to start–stop systems used in vehicles, as necessary in the driving of this type machine. During testing, an impact of a distance between a branch pile from the woodchipper, a number of operators on frequency of drive unit operating condition changes, and the mass and volume output (productivity) were considered. A percentage ratio of the active and passive (idle) operation in selected conditions of use was also determined. A low-power 9.5 kW engine-powered cylindrical-type woodchipper was used for testing. Material chopped in the chipper was freshly cut branches of oaks (Quercus L. Sp. Pl. 994. 1753) with a diameter in the largest cross-section ca. 80 mm and moisture content ca. 25%. Piles of branches were located at three different distances from the chipper, i.e., 3 m, 9 m and 15 m. Branches to the chipper were fed by one or two operators. It was demonstrated that the idle run time in tested conditions with one operator could be from 43% to 71% of the entire operating time. Frequency of operating condition changes when only one operator worked and fluctuated from ca. 6 to 2 times per minute. Increasing the number of operators from one to two had a slight impact on the frequency of operating condition changes (by ca. 7%) at the shortest distance from the chipper (3 m). However, at larger distances, the additional operator may increase the frequency of operating condition changes of the chipper by 77% for 9 m distance and 85% for 15 m distance. The mass and volumetric output of the cylindrical chipper in the most advantageous case is equal to 0.66 t/h and 3.5 m3/h, respectively. The increase of the branch pile distance from the chipper causes a drop in mass output by 32%, and volumetric output by 33.5%. The results of the tests confirmed the necessity for the development of low-power chipping machines designed for clearing operations rather than industrial production of biomass. A direction for development could be systems that adapt driving units to operating conditions, depending on a demand for the chipping process.

scholarly journals Changes of Insulation Properties of Photovoltaic Cables Caused by Ageing Treatment

2020 ◽  
Vol 6 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Juraj Packa ◽  
Vladimir Kujan ◽  
Daniel Štrkula ◽  
Vladimír Šály ◽  
Milan Perný
Keyword(s):  
Power Plants ◽  
Real Life ◽  
Life Time ◽  
Operating Conditions ◽  
Solar Panels ◽  
Font Size ◽  
Long Term Stability ◽  
Cable Systems

<span style="font-family: 'Times New Roman',serif; font-size: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-US">An important part of the photovoltaic power plants are cable systems. The dielectric properties of cables, reliability and durability depend on quality of production processes, operating conditions and degradation factors, as well. Expected lifetime of cable systems is more than 20-30 years in general. Their failure free operation and long-term stability of properties has a direct impact on the economic return of the investments. According to our experiences the tests in compliance with valid standards are not adequate to verify real life time during operation. Photovoltaic cables intended for use in outdoor applications for the connection between the solar panels and possible connection between panels and inverter were chosen for our experiments. <span style="-ms-layout-grid-mode: line;">The changes </span>of insulation resistance and breakdown voltage caused by some degradation factors, mainly water, are presented. This research was inspired by real failure in operation.</span>

Low-Power On-The-Fly Reconfigurable Iterative MIMO Detection and LDPC Decoding Design

2014 ◽  
Vol 496-500 ◽  
pp. 1825-1829 ◽  
Author(s):  
Ehsan Rohani ◽  
Jing Wei Xu ◽  
Gwan Choi ◽  
Mi Lu
Keyword(s):  
Low Power ◽  
High Performance ◽  
Signal To Noise Ratio ◽  
Wireless Systems ◽  
Operating Conditions ◽  
Mimo Detection ◽  
Ldpc Decoding ◽  
Wide Range ◽  
Multiple Input

Manufacturing and operation of wireless systems require a practical solution for achieving low-power and high-performance when using advance communication apparatus such as that using multiple-input and multiple-output (MIMO). Often algorithm solutions achieve very high performance but over only in a narrow range of operating parameters. This paper presents a hardware design of MIMO detection that allows real-time switching between various algorithms and detection effort to achieve high performance over the wide-range of signal to noise ratio (SNR) found in realistic operating conditions. We illustrate a design with over 80% reduction in detection power that satisfies the required quality of service (QoS) in SNRs (Eb/No) as low as 8.7 dB.

Variation of thermal resistance with input current and ambient temperature in low-power SMD LED

2018 ◽  
Vol 35 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Muna E. Raypah ◽  
Dheepan M.K. ◽  
Mutharasu Devarajan ◽  
Shanmugan Subramani ◽  
Fauziah Sulaiman
Keyword(s):  
Low Power ◽  
Thermal Resistance ◽  
Ambient Temperature ◽  
Light Emitting Diode ◽  
Operating Conditions ◽  
Input Current ◽  
Junction Temperature ◽  
Total Thermal Resistance ◽  
Content Type ◽  
Thermal Transient

Purpose Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED. Design/methodology/approach Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software. Findings As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔRthJS) and total thermal resistance (ΔRthJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔRthJS and ΔRthJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature. Originality/value Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.

scholarly journals A Study of Early post-operative wound complications of spina bifida aperta repair “Incidence and Risk Factors”

2018 ◽  
Vol 60 (2) ◽  
pp. 89-92
Author(s):  
Ali K. AL-Shalchy ◽  
Wameedh Q. Abdul-hussein
Keyword(s):  
Risk Factors ◽  
Wound Complications ◽  
Spina Bifida Aperta ◽  
Csf Leakage ◽  
High Incidence ◽  
Operation Duration ◽  
The Third World ◽  
Duration Of Operation ◽  
Type Of Delivery ◽  
Early Wound

Background: Myelomeningocele is the single most common congenital anomaly that affects the CNSand vertebral column. The third world countries having a higher incidence. The management is usuallysurgical with relative high incidence of complications.Objectives: to evaluate the possible risk factors that may predispose to early wound complications ofmyelomeningocele.Methods: This prospective study was carried out in the Surgical Specialization Hospital in Medical CityComplex - Baghdad from 2009-2012. 147 cases were included in the study. Requested data weregestational age, type of delivery, gender, age at operation, type of suturing of the wound, tension ofsuturing, duration of operation, site of the lesion, ruptured vs non ruptured myelomeningocele, associatedshunting, peri-operative stay in hospital and associated jaundice.Result: Forty four (44 %) of the total developed complications. All premature infants developedcomplications. Hydrocephalic cases was associated with higher rate of complication (86%). Type ofdelivery, age at operation, duration of operation, ruptured cases and site of the lesion were not associatedwith complications.Conclusion: Myelomeningocele was predominantly affecting female. Most of the complications werewound infection with or without dehiscence, CSF leakage or seroma.

scholarly journals Analysis, Design and Empirical Validation of a Smart Campus Based on LoRaWAN

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Paula Fraga-Lamas ◽  
Mikel Celaya-Echarri ◽  
Peio Lopez-Iturri ◽  
Tiago Fernández-Caramés ◽  
Leyre Azpilicueta ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Smart City ◽  
Operating Conditions ◽  
Wide Area ◽  
Empirical Validation ◽  
Promising Alternative ◽  
Traffic Lights ◽  
Medium Scale ◽  
Smart Campus

Internet of Things (IoT) applications for smart environments demand challenging requirements for wireless networks in terms of security, coverage, availability, power consumption, and scalability. The technologies employed so far to cope with IoT scenarios are not yet able to manage simultaneously all these demanding requirements, but recent solutions like Low-Power Wide Area Networks (LPWANs) have emerged as a promising alternative to provide low-cost and low-power consumption connectivity to nodes spread throughout a wide area. Specifically, the Long-Range Wide Area Network (LoRaWAN) standard is one of the most recent developments, receiving attention from both industry and academia. This work presents a comprehensive case study on the use of LoRaWAN under a realistic scenario within a smart city: a smart campus. Such a medium-scale scenario has been implemented through an in-house-developed 3D ray launching radio planning simulator that takes into consideration traffic lights, vehicles, people, buildings, urban fixtures, and vegetation. The developed tool is able to provide accurate radio propagation estimations within the smart campus scenario in terms of coverage, capacity, and energy efficiency of the network. These results are compared with an empirical validation in order to assess the operating conditions and the system accuracy. Moreover, the presented results provide some guidelines for IoT vendors, network operators, and city planners to investigate further deployments of LoRaWAN for other medium-scale smart city applications.

STUDY OF ELECTRIC MOTORS FOR AUTOMATED SOLAR PANEL CLEANING SYSTEMS

2020 ◽  
pp. 74-85
Author(s):  
D.I. Amirov ◽  
◽  
Yu.N. Zatsarinnaya ◽  
A.G. Logacheva ◽  
E.A. Fedotov ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Electric Drive ◽  
Payback Period ◽  
Solar Panel ◽  
Automated System ◽  
Low Power Consumption ◽  
Electric Motors ◽  
Solar Panels ◽  
Design Development

One of the main problems faced during solar panels operation is the contamination of their front surfaces. This paper presents the results of solving that problem by means of new equipment design development. The authors have proposed an autonomous and reliable cleaning method with low power consumption and no possibility of panel shading. In connection with the noted criteria, an automated system with a short payback period was created. The article presents a description of the developed device, the results of a study on the choice of an engine, an electric drive. The use of an automated system for cleaning solar panels will allow minimizing the share of human participation in the solar panels cleaning.

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