Enhancement of Poly-Crystal PV Panels Performance by Air-to-Air Heat Exchanger Cooling System

The temperature of silicon Poly-Crystal photovoltaic (PV) solar panels has a significant impact on their efficiency emphasizing the necessity of cooling approach to be used. The current study looked at the impact of adopting a unique forced convictive air-to-air heat exchanger as a cooling approach to boost the efficiency of PV solar panels, as efficiency of silicon Poly-Crystal PV solar panels would decrease as its temperature increased. The research was carried out experimentally with both an uncooled and cooled PV system. A unique cooling system for PV panels was designed and experimentally investigated in Amman, Jordan included a heat exchanger connected to a blower that drove ambient air over the back-panel surface and a chimney to draw the cooled air outside. This cooling system would improve the PV panel's efficiency. It was found that by directing cooled air over the bottom surface of the PV module at an ideal rate of 0.01020 m3/s, the temperature of the PV module could be reduced from an average of 40 °C (without cooling) to 34 °C. As a result, the efficiency and output power of PV modules increased by roughly 2 % and 12.8 %, respectively.

The repolarization pattern of ARVC patients, healthy gene carriers and controls as analyzed with a 252-leads Body Surface Mapping Vest

Background Repolarization abnormalities have a central role on the diagnosis of ARVC according to recent HRS consensus document from 2019 stating that T wave inversion in the right precordial leads is a major criteria if it appears in V1-V3 or a minor criteria if it appears in only V1-V2. Purpose The aim of our study was to investigate whether repolarization patterns as recorded by a Body Surface Mapping (BSM) system consisting of a vest with 252 ECG leads, could differentiate ARVC patients and even gene carriers from normal individuals. Our hypothesis is that the method can potentially identify repolarization disturbances earlier or better than conventional 12-lead ECG. Method 12 definite ARVC patients, 20 healthy gene carriers and 8 family members who tested negative for the family mutation (controls) were included. All patients underwent 12-lead ECG, including right precordial leads (V4R) and BSM recordings. Repolarization (T-wave polarity and concordance with QRS complex vector) was analyzed qualitatively in all BSM recordings, the results of which were displayed on a color code map (fig.1). Results The mean age was 49.6, 43.6 and 38.8 years in ARVC patients, healthy gene carriers and controls, respectively. The number of males in the three groups were 8/12, 8/20 and 5/8, respectively. All 8 controls had similar repolarization patterns with negative and concordant T waves on the right back panel, and T waves that successively changed from negative concordant (green) to positive disconcordant (red) and finally positive concordant (blue) on the left front panel (pattern 1). All 12 ARVC patients had different repolarization patterns as compared to the controls. Two of these patients had no apparent repolarization changes on conventional 12 lead ECG. The pattern type 2 repolarization, as defined by same pattern as the controls at the right back panel but different pattern at the front left panel was seen in 3/12 ARVC patients. The remaining 9 ARVC patients had different repolarization patterns both on the front and on the back panel (pattern 3). Among gene carriers, 15 had a normal repolarization pattern (pattern 1) and 5 demonstrated an abnormal repolarization pattern (4 had pattern type 2 and one pattern 3) despite normal surface ECG. Conclusions Using BSM recordings, abnormal repolarization patterns can be detected in all ARVC patients, even in those without repolarization changes on conventional surface ECG. The observation that 25% of gene carriers had divergent repolarization patterns, may indicate an early stage of the disease, and be used as an early diagnostic marker of the disease. Further and larger studies are warranted to confirm these observations. Repolarisation patterns recorded by BSM Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Selanders Stiftelse

TERTIARY X-RADIATION—A PROBLEM FOR STAFF PROTECTION?

The influence of tertiary x-radiation on the radiological staff is widely unknown. Tertiary radiation is caused as the scattered radiation of the patient impacts the walls, floor, ceiling and surrounding air. The question that arises is does tertiary x-radiation provide a relevant contribution to the staff doses. The impact of tertiary radiation was investigated by means of measurements of the personal dose equivalent Hp(10) on an anthropomorphic Alderson Rando male phantom and also on operators/assistants staying in clinical practice. Further, the protective effect of lead foils, especially under tertiary radiation was also investigated. Correlations could be derived for clinical angiographic/interventional procedures between dose area products (DAPs) and dose length products (DLPs) vs. dorsal doses of staff persons. Generally, the staff doses that are a result of tertiary radiation depend on the x-ray energy and range from 0.15 to 0.55% of the scattered radiation impact caused by irradiation of the patient. Hence, a back panel with 0.125-mm lead equivalent is sufficient to protect the staff from tertiary radiation created within the room environment.

A New Method to Detect Zeolite Breath Sensor Response Based on Low-Power Square-Wave Sources

Low-power A.C. generators of square-wave or sinusoidal signals can be used in combination with impedimetric sensors to detect stimuli on the basis of the voltage drop taking place at the sensor electrodes. When a.c. generators with a power of only a few µ-Watts are used, this approach becomes extremely sensitive. A very low-power generator is the LCD back panel driving signal, which has a flipping polarity with a voltage of 3-5Vpp, depending on the generator model. This type of square-wave generator is contained in many low-cost handheld digital multimeters, and it is used as signal tracer to test, for example, low-frequency amplifiers. As an example, this method has been used to acquire a human breath rate pattern, by using a zeolite-based water sensor. If the generator I-V characteristics has been measured, the achieved breath pattern can be converted from a voltage drop vs. time graph to an impedance or current intensity vs. time graph.

Effect of Al alloy back panel on the dynamic penetration and damage characteristics of ceramic composite armors

This paper mainly focuses on the investigation of dynamic penetration and damage characteristics of a hybrid ceramic composite armor normally impacted by 12.7 mm armor piercing incendiary projectiles. The hybrid ceramic composite armor was composed of a ceramic cylinder layer, a Ti–6Al–4V plate, an ultrahigh molecular weight polyethylene (UHMWPE) composite layer, and an Al alloy panel. Three different areal densities of composite laminates with 82, 87, and 92 kg/m2 were tested. 3D finite element model of the ceramic composite armor was generated in ABAQUS, and the simulation results were employed to study the damage evolution. The effect of alumina ceramic cylinders layer on the ballistic performance and the failure mechanisms of Ti–6Al–4V and UHMWPE after ballistic impact were examined by experimental and simulative results. According to the numerical and analytical models, an optimal thickness range of Al alloy back panel was found in minimizing areal density of the ceramic composite armor.

The Effect of Round Flow Path Discharger and Back Panel Open Ratio on a Performance of Open Refrigerating Showcase

Numerical study is conducted to confirm the effect of round flow path control and back panel open ratio on a performance of open refrigerating showcase in this study. The rounding control is applied to flow path of air discharger in various radii and the punched panel with various open ratios is applied to back panel of showcase. These structural changes have a significant impact on its aircurtain performance because both changes can affect flow pattern of showcase. To prove it, the two-dimensional steady simulation is performed using [Formula: see text]–[Formula: see text] turbulent model. The performance of showcase is assessed using entrainment factor which is a ratio between cooled air and ambient air at the suction of refrigerating part. As a result of simulation, the curved path at air discharger reduces the entrainment factor by a maximum 9% less than typical design. The curved flow path removes the dead zone at the honeycomb structure of discharger. In addition, it is found that there is an optimal back panel open ratio at the storage space of the showcase. When the back panel open ratio is 0%, the cooled air from the discharge is attached to the cold storage area because of the Cowanda effect. However, the Cowanda effect is eliminated when back panel open ratio increases. Results address that the entrainment factor remains almost the same at back panel open ratio 3.93% or more. Lastly, the simulation of showcase with product in cold storage area is conducted to confirm the structure changes effect on performance of real use showcase according to KS Standard.

Vibroacoustic Optimization Study for the Volute Casing of a Centrifugal Fan

A numerical optimization is presented to reduce the vibrational noise of a centrifugal fan volute. Minimal vibrational radiated sound power was considered as the aim of the optimization. Three separate parts of volute panel thickness (ST: the side panel thickness; BT: the back panel thickness; FT: the front panel thickness) were taken as the design variables. Then, a vibrational noise optimization control method for the volute casing was proposed that considered the influence of vibroacoustic coupling. The optimization method was mainly divided into three main parts. The first was based on the simulation of unsteady flow to the fan to obtain the vibrational noise source. The second used the design of experiments (DoE) method and a weighted-average surrogate model (radial basis function, or RBF) with three design variables related to the geometries of the three-part volute panel thickness, which was used to provide the basic mathematical model for the optimization of the next part. The third part, implementing the low vibrational noise optimization for the fan volute, applied single-objective (taking volute radiated acoustical power as the objective function) and multi-objective (taking the volute radiated acoustical power and volute total mass as the objective function) methods. In addition, the fan aerodynamic performance, volute casing surface fluctuations, and vibration response were validated by experiments, showing good agreement. The optimization results showed that the vibrational noise optimization method proposed in this study can effectively reduce the vibration noise of the fan, obtaining a maximum value of noise reduction of 7.3 dB. The optimization in this study provides an important technical reference for the design of low vibroacoustic volute centrifugal compressors and fans whose fluids should be strictly kept in the system without any leakage.

The Conservation of a Victorian Taxidermy Display Case

A Victorian taxidermy display case presented conservation challenges and decisions that included ethical and methodological considerations regarding the treatment required. The case was donated to Auckland Museum in 2006 by the Howick Historical Society and contains assorted birds from North and South America. With limited records received from the Howick Society, there was no further information regarding its provenance or history of conservation. Therefore consultation was maintained with the Curator of Applied Arts and Design throughout the process. Firstly, the case contained numerous birds of different species mounted to a tree-like structure, constructed from wire wrapped in natural fibre and foliage. It was completely sealed with access only possible by removing the back panel, and it was not known if any of the components were attached to this. Secondly, the birds were in very poor condition; some had fallen off their branches, many had damaged feathers, and few had either a loose head or missing tail. Lastly, there was also evidence of pest infestation in both the case and its contents, so investigation was required to determine if this was active. This poster will address the three main concerns covering the approaches to techniques in the remedial treatment of taxidermy birds, the preventive conservation treatments chosen to tackle the pest infestation and how conservation can aid research in determining provenance.