Tilt Angle Optimality Criteria for Stand Alone PV Systems

The conventional approach to optimizing tilt angles for fixed solar panels aims to maximize energy generation over the entire year. However, in the context of a supply controlled electric grid, where solar energy availability varies, this criterion may not be optimal. This study explores two alternative optimization criteria focused on maximizing baseload supply potential and minimizing required storage capacity to address seasonality in energy generation. The optimal tilt angles determined for these criteria differed significantly from the standard approach. This research highlights additional factors crucial for designing solar power systems beyond gross energy generation, essential for the global transition towards a fully renewable energy-based electric grid in the future.

Optimum Tilt Angle of Flow Guide in Steam Turbine Exhaust Hood Considering the Effect of Last Stage Flow Field

Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional （3D） Reynolds time-aver- aged N-S equations and standard k-e turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30~ to 40~, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effectiveenthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.

Effects of tilt angle of disk plough on some soil physical properties, work rate and wheel slippage under light clay soil

Standard Disk Plough(SDP)is the integral element of traditional farming system in Middle and Northern Sudan.In SDP,the tilt angle between the planes of the cutting edge of the disk which is inclined to a vertical line may be altered according to the field conditions.Tractor drivers usually use an angle close to maximum in order to decrease the tillage depth,consequently decreasing power requirements,without considering the tillage quality and the impact on the soil properties.This experiment was conducted at the College of Agricultural Studies farm of Sudan University of Science and Technology to study the effects of three tilt angles(15°,20°and 25°)on soil bulk density,mean weight diameter,wheel slippage,work rate(or effective field capacity)and soil volume disturbed using mounted disk plough.The nature of soil on the farm found to be light clay.The theoretical forward speed was maintained at 6 km/h.The results showed that increasing tilt angle of the plough significantly(p<0.05)increased the bulk density,mean weight diameter and field capacity while significantly decreasing the tractor wheel slippage and soil volume disturbance.

Effect of tilt angle on the performance and electrical parameters of a PV module:Comparative indoor and outdoor experimental investigation

Photovoltaic(PV)system’s performance is significantly affected by its orientation and tilt angle.Experimental investigation(indoor and outdoor)has been carried out to trace the variation in PV performance and electrical parameters at varying tilt angles in Malaysian conditions.There were two experimental modus:1)varying module tilt under constant irradiation level,2)varying irradiation intensity at the optimum tilt set up.For the former scheme,the irradiation level was maintained at 750 W/m^(2),and for the later arrangement,the module tilt angle was varied from 0 o to 80 o by means of a single-axis tracker.Results show that under constant irradiation of 750 W/m^(2),every 5 o increase in tilt angle causes a power drop of 2.09 W at indoor and 3.45 W at outdoor.In contrast,for the same condition,efficiency decreases by 0.54%for indoor case and by 0.76%at outdoor.On the other hand,for every 100 W/m^(2)increase in irradiation,solar cell temperature rises by 7.52℃at indoor and by 5.67℃at outdoor.As of module electrical parameters,open-circuit voltage,short-circuit current,maximum power point voltage and maximum power point current drops substantially with increasing tilt angle,whereas fill factor drops rather gradually.Outdoor experimental investigation confirms that the optimum tilt angle at Malaysian conditions is 15 o and orienting a PV module this angle will maximize the sun’s energy captured and thereby enhance its performance.

Influence of the inner tilt angle on downwash airflow field of multi-rotor UAV based on wireless wind speed acquisition system

The downwash airflow field is an important factor influencing the spraying performance of plant protection UAV,and the structural design of rotors directly affects the characteristics of the downwash airflow field.Therefore,in this study,three-dimensional models of a six-rotor UAV with various inner tilt angles were established to simulate and analyze the influence of the inner tilt angle on the downwash airflow field based on the Reynolds average NS equation,RNG k-εturbulence model,etc..On this basis,a wireless wind speed acquisition system using the TCP server was developed to carry out the test through the marked points with real-time detection.The simulation results show that,the variation of inner tilt angles of the six-rotor UAV did not cause significant difference in the time dimension of the downwash airflow field,and with the change of the inner tilt angle from 0°to 8°,the distribution of downwash airflow field tended to obliquely shrink towards the central axis direction,and the amplitude of linear attenuation of airflow speed was also increased,which the difference of attenuation amplitude was 1 m/s.Besides,under the different inner tilt angle,the airflow velocity in“lead in area”was significantly greater than that in the“lead out area”,and the difference of air velocity distribution in space would affect the uniformity of droplet deposition.Through the calibration test,the measurement accuracy error of the developed system was lower than 0.3 m/s,and the adjusted R2 of the calibration fitting equation was higher than 0.99.The test and simulation values at test points from 0.2-2.3 m below the rotors exhibit the same variation trend,and the average relative error at the height of 1.1-2.3 m below the rotors and 0.2-0.8 m near the ground was within 10%and 20%,respectively.The simulation and test results were highly reliable,which could provide basis and reference for the design and optimization of plant protection drones.

Influence of Tilted Angle on Effective Linear Energy Transfer in Single Event Effect Tests for Integrated Circuits at 130 nm Technology Node

A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130？nm CMOS bulk Si and silicon-on-insulator （SOI） technologies. The effectiveness of linear energy transfer （LET） with a tilted ion beam at the 130？nm technology node is obtained. Tests of tilted angles θ=0 ° , 30 ° and 60 ° with respect to the normal direction are performed under heavy-ion Kr with certain power whose LET is about 40？MeVcm 2 /mg at normal incidence. Error numbers in D flip-flop chains are used to determine their upset sensitivity at different incidence angles. It is indicated that the effective LETs for SOI and bulk Si are not exactly in inverse proportion to cosθ , furthermore the effective LET for SOI is more closely in inverse proportion to cosθ compared to bulk Si, which are also the well known behavior. It is interesting that, if we design the sample in the dual interlocked storage cell approach, the effective LET in bulk Si will look like inversely proportional to cosθ very well, which is also specifically explained.

Coverage Optimization of LTE Networks Based on Antenna Tilt Adjusting Considering Network Load

In this paper,we investigate the coverage optimization for LTE networks considering the network load. The network coverage is defined as the number of served users of evolved Node B(eNB)which is determined by e NBs' antenna tilt angles(ATA). The coverage is optimized by optimizing the number of served users based on the Modified Particle Swarm Optimization(MPSO)algorithm. Simulation results show that both the number of served users by each e NB and the system throughput are significantly increased. As well,the average load and the bandwidth efficiency of the network are improved.

Estimation of Solar Radiation on Horizontal and Tilted Surface over Bangladesh

To estimate the monthly averaged solar radiations (global, diffuse and direct solar radiation) on horizontal surface and tilted surface over 10 stations (districts) in Bangladesh, thirty years monthly averaged data of various meteorological parameters namely the monthly averaged value of maximum temperature, minimum temperature, humidity and sunshine hours were used in this study. Assessment of the solar resources for the solar based renewable energy technologies of Bangladesh may be based upon this kind of measured data analyzed study. This study tried to estimate the monthly averaged solar radiation by presenting data in table and graph and finally analyze through equations and descriptions. Correlation between the measurements of monthly averaged solar radiation and the meteorological parameters was given for the selected 10 stations in Bangladesh. In conclusion, we tried to make a comparison among solar radiation on horizontal surface, fixed 20.83 ° (degree) optimal tilt angle and variable optimal tilt surface at Dhaka station.

Structural Study of the Kakobola Area and Its Surroundings by Detecting the Edges of Gravity Anomaly Sources

The area covered by this study is the county of Kakobola and its surroundings. Previous studies show that those related to the study of depths by the gravity method, using other techniques, are not always carried out until now. The main goal of this article is the gravimetric characterization of our area by other approach. The interest is not only to map the lineaments and to know their dip, but also to estimate the depths of these different anomalies. The methods used for this study are the first total horizontal derivative (FTHDT), tilt angle (TA), analytical signal (AS) and horizontal gradient magnitude (HGM). The processing of the complete Bouguer anomalies (CBA) data was done mainly through software. Data analysis using the semi-finished body depth method shows depths ranging from 7.49 m to 224.6 m. Data analysis using the AS method shows values ranging from 41.7 mGal/m to 510 mGal/m. The fractures and/or geological contacts in our study area show dips ranging from -73.73° to 68.16° and North-South orientation according to the tilt angle method. The FTHDT shows several lineaments, a NE oriented fracture of Kakobola and low dip values which suggest a tabular structure of the subsurface in our study area. According to the HGM, the study area shows several preferential directions of fractures and/or geological contacts whose the most frequent directions are the NNE-SSW and WNW.

Determining the Optimal Parameters of an Advanced Linter Machine

In this article, research was conducted to improve Linter machines that remove short fibers remaining in ginned cotton seeds at cotton ginneries. The study examined the effect of changing the dimensions of the brush drum, guide and mesh surface in the cleaning device proposed for the linting machine on the movement of the peg and the cleaning efficiency, and the highest level of efficiency in separating impurities from the peg was determined. During the study, the main factors influencing the effective operation of the improved linting machine were identified, the limits of their values were determined, and studies were carried out using the mathematical modeling method. As a result, at the values of the given coefficients, efficient operation of the improved linting machine was observed, that is, the lint cleaning efficiency reached 55.1%.

The Use of Edge Enhancement Methods and Euler Deconvolution to Estimate an Ore Deposit Depth from Gravity Data

The Hercynian massif of the central Jebilet (Morocco) is characterized by the outcrop of many gossans with great economic importance. This work focuses on interpreting gravity data of Benslimane gossan, located about thirty kilometres to the North-West of Marrakech. The residual gravity map of the study area highlights several anomalies which coincide with the mining and geological contexts. Applying edge detection methods, for example, tilt angle derivative (TDR), the total horizontal derivative of the tilt angle derivative (HDR_TDR) and the 3D Euler deconvolution, allowed us to estimate the depth of the Benslimane deposit. As a result, the average depth of the ore deposit was estimated to exceed 200 m. The results are promising, and the processing methods must be applied to the other gossan in the Jebilet massif for further exploration studies.

Dependence of single event upsets sensitivity of low energy proton on test factors in 65 nm SRAM

In order to accurately predict the single event upsets （SEU） rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and position of SEU peak of low energy protons （LEP） in 65 nm static random access memory （SRAM） are quantitatively evaluated and analyzed based on LEP testing data and Monte Carlo simulation. The results show that different initial proton energies used to degrade the beam energy will bring about the difference in the energy distribution of average proton energy at the surface and sensitive region of the device under test （DUT）, which further leads to significant differences including the height of SEU peak and the threshold energy of SEU. Using the lowest initial proton energy is extremely important for SEU testing with low energy protons. The proton energy corresponding to the SEU peak shifts to higher average proton energies with the increase of the tilt angle, and the SEU peaks also increase significantly. The reduction of supply voltage lowers the critical charge of SEU, leading to the increase of LEP SEU cross section. For standard 6-transitor SRAM with bit-interleaving technology, SEU peak does not show clear dependence on three test patterns of logical checkerboard 55H, all＂ 1＂, and all ＂0＂. It should be noted that all the SEUs in 65 nm SRAM are single cell upset in LEP testing due to proton＇s low linear energy transfer （LET） value.

Guided transmission of oxygen ions through Al_2O_3 nanocapillaries

The transmissions of oxygen ions through Al2O3 nanocapillaries each 50 nm in diameter and 10 μm in length at a series of different tilt angles are measured, where the ions with energies ranging from 10 to 60 keⅤ and charge states from 1 up to 6 are involved. The angular distribution and the transmission yields of transported ions are investigated. Our results indicate both the existence of a guiding effect when ions pass through the capillary and a significant dependence of the ion transmission on the energy and the charge state of the ions. The guiding effects are observed to be enhanced at lower projectile energies and higher charge states. Meanwhile, the results also exhibit that the transmission yields increase as the tilt angle decreases at a given energy and charge state.

Theoretical Comparative Energy Efficiency Analysis of Dual Axis Solar Tracking Systems

This paper developed a theoretical model substantially based on the principle that only the normal component of solar radiation is actually converted into electrical energy. This theoretical model helped to predict minimum and maximum daily energy gain (compared to static PV system tilted with certain angle) when using dual axis PV solar tracking systems, at any given location on earth without prior experimental data. Based on equations derived from model, minimum and maximum energy gain is computed and summarized in tables of minimum and maximum. Furthermore, the model equations could be used to set up future experimental studies related to the matter.

Application of a screw conveyor with axial tilt blades on a shearer drum and investigation of conveying performance based on DEM

Screw conveyors are widely employed in industrial fields for conveying bulk materials.The shearer drum which uses the screw conveying principle is responsible for excavation and conveying coal particles onto the chain conveyor.Screw conveyor performance is affected by potential factors,such as the blade axial tilt angle and style,core shaft form and diameter.The effect of blade axial tilt angle on the conveying performance was investigated with the help of DEM.In the case of the screw conveyor,the mass flow rate,and particle axial velocity increased with increasing positive axial tilt angle,and declined with increasing negative axial tilt angle.In the case of the drum,the mass flow rate,particle axial velocity,and loading rate first increased and then decreased with increasing positive axial tilt angle,and decreased with increasing negative axial tilt angle.These results can be considered as a benchmark for screw conveyor and drum structural designs with axial tilt screw blades.

SEDIMENTATION OF CYLINDRICAL PARTICLES IN A VISCOELASTIC LIQUID:SHAPE-TILTING

Aluminum and Teflon cylindrical particles with flat ends are dropped in aqueous Polyox solutions. The terminal equilibrium orientation of the particles is characterized by the tilt angle, a, formed by the major axis of the cyl-inder with the horizontal. It is observed that a is a function of the aspect ratio L=L/d, where L is the length and d is the diameter of the cylinder, and that it varies continuously from a certain angle, a0, to 90, as L increases toward a value L0. For a given shape, both a0 and L0 depend on the density of the cylinder and the properties of the liquid used. For the particles we have considered the value of L0 is of the order of 2. This 搕ilt-angle phenomenon?disappears as soon as the ends of the cylinder are round. Specifically, cylinders of the same density and with the same aspect ratio but with round ends, when dropped in the same polymeric solution will reach a final orientation with a=90. Therefore, this tilt-angle phenomenon seems to be tightly related to the shape of the particle.

Application of the multi-planar reconstruction in endovascular treatment of type B aortic dissection

Background Although Multi-planar reconstruction （MPR） has been considered a diagnostic imaging technique that observes more perspectives for diseases,few people have applied it surgically.In fact,MPR is also very useful to clinical operation,especially for patients with type B aortic dissection.It helps the surgeon to locate accurately with more information about aortic dissection,so that the safety and effectiveness of operation can be improved.This study examined the application of the MPR in intraoperative DSA imaging for precise positioning by accurately obtaining a crosssection,a spin angle of the coronal plane,and a tilt angle of the sagittal plane in treatment of type B aortic dissection.Methods The conventional and the MPR approaches were compared on positioning the aortic arch for surgery.A group of 40 patients （group A） and another group of 42 patients （group B） was sampled.About the comparison of baseline characteristics,a fourfold table X2 test was conducted on gender,and two independent samples t-test was applied to age between group A and group B.Spin as well as tilt angles for group A were obtained from the patients using both approaches,and their effectiveness was compared with pair t-tests; The MPR data guided stent-grafting in this group.Stent graft placement of group B was based on the conventional approach.Percentages of proximal distributed markers as well as incidences of complications were collected from both groups after stent graft placement.They were also compared with a fourfold table X2 test.Results Gender difference was not found between group A and group B （X2=0.80,P ＞0.05）,and age difference was not statistically significant （F=2.55,homogeneity of variance,t=-1.46,P ＞0.05）.A significant difference was found between the conventional and the MPR approaches for spin angle （t=9.17） as well as tilt angle （t=-2.07）,P ＜0.05.Percentage of proximal distributed markers （5.0％） of group A was significantly lower than that of group B （42.9％）,X2=15.92,P ＜0.05;and incidence of complications （5.0％） of group A was also significant lower than that of group B （21.4％）,X2=4.76,P ＜0.05.Conclusions Application of the MPR facilitated intraoperative angle adaption and led to satisfactory DSA.It is feasible in endovascular treatment of type B aortic dissection,and can effectively and safely guide surgical operations.

Investigation on the stability and anti-eccentric load margin of a novel structure bearing lubricated by low viscosity medium

The paper studies the anti-eccentric load margin of a novel structure bearing lubricated by low viscosity medium. The lubrication dynamic model considering journal inclination angle is established. The effects of different speeds, loads, and tilted angles on the interface attributes of the bearing under typical working conditions are studied. The results show that the special structure bearing has self-stability margin of anti-tilted and anti-eccentric load. Particularly under different speed conditions, analyses show that the eccentric load has little influence on the static/dynamic characteristics of the bearing. Under the same conditions, the stability margin of the bearing is higher than that of traditional bearings. The research provides a theoretical basis for the application of such kinds of special structure bearings.