Hole Type Research Articles

Charge pumping in solar cell structure

Modern understanding of the material science of semiconductor silicon allowed the authors to propose a new concept of the so-called “charge pumping” in the structures of photovoltaic converters or solar cells. This paper presents theoretical estimates of the rate of separation and collection of light-generated charge carriers in the structures of conventional silicon solar cells and charge-pumped solar cells. Relatively cheaper so-called “solar silicon” of p-type conductivity is typically used in the industrial production of solar cells. This type of silicon is particularly prone to the formation of thermodonor centers. Partial or, at higher temperatures (about 400 °C), even complete overcompensation of the hole type of conductivity in the base region may occur as a result of prolonged heating. This paper presents an original model describing the local formation of n+ regions in the solar cell structure by the so-called “local photon annealing”. These regions were named “charge pumps”. Experimental data on the formation of n+ regions as a result of Li diffusion are reported as an experimental confirmation of the theoretical estimations made in this work. Comparative volt-ampere characteristics of experimental charge-pumped photovoltaic converters and conventional solar cells are presented, showing an up to 30% increase in the short-circuit current Js.c for the experimental structures under standard illumination (AM1.5). The proposed technological aspects of charge-pumped photovoltaic converter fabrication deliver a cheap process and can be implemented in the industrial production of solar cells with little effort.

Quarks species in a cold genesis theory; theoretic implications of a Vortical quark model

By the author’s cold genesis theory (CGT), based on the Galileian relativity, it was argued the possibility to explain the massic spectrum of the elementary particles by two species of preonic quasi-crystalline quarks: A) preonics –formed by basic preons z0(34 me) which form bosonic preons z2(4z0) and zpi(7z0) , and B) quarkonics – formed by 3n preonic quarks (4≥n≥1) (mainly –v- or/and s-quarks) or as crystalline cluster of 7x5 = 35 preonic or quarkonic quarks: (p+;n−) –nucleonic quarks or l±, s±,v± -preonic quarks, or c- or b- quarkonic quarks, (‚charm’, ‚botton’), in two flavors: f=1-of Standard model’s variant and f = 2 –of Souza/CGT’s variant. Because the basic z0-preons are explained as cluster of paired degenerate electrons, the strong forces between quarks and particles can be naturally explained by the existence of a permanent etherono-quantonic vortex around the super-dense kernel of electron generated by etherono-quantonic winds of the quantum vacuum and by an etheronic centripetal force of Magnus type. As consequence, in CGT can be argued a model of‚ gravistar’ having a shell of dark energy but also of photons vortexed around a rotational hard core (HC) of black hole type which –by matter→energy conversion can obtain periodically an antigravitic (pseudo)charge MA, by the releasing of heavy etherons of the destroyed degenerate electrons’ vortices. The antigravitic field of an enough high value of MA, produced by the friction between the surface of an internal hard core (HCi) of HC, of black hole type, and the interior surface of a crystalline shell of current strange cold quarks, HCe, could be –in this case, a natural equivalent of the‚ dilaton’ field considered in the EMD theories.

Astrophysical and electromagnetic emissivity properties of black holes surrounded by a quintessence type exotic fluid in the scalar–vector–tensor modified gravity

The astrophysical consequences of the presence of a quintessence scalar field on the evolution of the horizon and on the accretion disk surrounding a static black hole, in the scalar–vector–tensor version of modified gravity (MOG), are investigated. The positions of the stable circular orbits of the massive test particles, moving around the central object, are obtained from the extremum of the effective potential. Detailed calculations are also presented to investigate the light deflection, shadow and Shapiro effect for such a black hole. The electromagnetic properties of the accretion disks that form around such black holes are considered in detail. The energy flux and efficiency parameter are estimated analytically and numerically. A comparison with the disk properties in Schwarzschild geometry is also performed. The quantum properties of the black hole are also considered, and the Hawking temperature and the mass loss rate due to the Hawking radiation are considered. The obtained results may lead to the possibility of direct astrophysical tests of black hole type objects in modified gravity theories.

The Impact of Hole Diameter on the Molded and Drilled Holes in Jute-Fiber-Reinforced Epoxy Composites

Damage caused by the drilling process is the most common reason for the rejection of composite parts and components that include holes. This is especially true in the case of laminated composites. The purpose of the current experimental investigation is to investigate the efficiency of hole formation when the component is in the molding phase. The mechanical properties of molded and drilled holes in jute-fiber-reinforced epoxy composites have been compared in a study that was carried out with the purpose of conducting an examination of these features. It was discovered that the molded holes operate much better than the drilled holes when it comes to jute fiber/epoxy composite materials. This was the conclusion reached after observing both types of holes. The maximum tensile load that was taken by molded hole specimens of composites with hole diameters of 4 mm and 8 mm was reported to be 48.8% and 101.5% greater, respectively, than the maximum tensile load that was taken by drilled hole specimens of composites with the same diameter. In addition, the load-extension curves demonstrate that the specimens that were manufactured with molded holes were able to achieve a larger degree of extension when compared to those that were manufactured with drilled holes.

Reduced Kiselev black hole

The Kiselev model describes a black hole surrounded by a fluid with equations of state p_r/rho =-1 and p_t/rho =(3w+1)/2 respectively in radial and tangential directions. It has been extensively studied in the parameter region -1<w<-1/3. If one rids off the black hole and turns to the region -1/3<w<0, i.e. p_t>0, then a new horizon of black hole type will emerge. This case has been mentioned in Kiselev’s pioneer work but seldom investigated in the literature. Referring to it as reduced Kiselev black hole, we revisit this case with attention to its causal structure, thermodynamics, shadow cast and weak-field limit. An alternative interpretation and extensions of the black hole are also discussed.

Study of the Free Randomly Moving Electron Transport Peculiarities in Metals

In this study, we review some aspects of the application of free randomly moving (RM) electron density and its probability density function distribution to the main free electron transport characteristics of elemental metals. It is shown that metal atom thermal vibrations not only produce free RM electrons, but also produce the same number of electronic defects (weakly shielded ions). The general expressions for the drift mobility, diffusion coefficient, and mean free path of randomly moving electrons are presented. It is shown that the scattering of free RM electrons is mainly due to electronic defects, which cause the distortion of the periodic potential (or the charge density) distribution in the periodic lattice. The resistivity of the elemental metal is caused by electronic defect scattering, taking into account the exchange in the thermal energies between phonons and free RM electrons. Special attention is paid to the analysis of the Hall effect measurement data: the Hall coefficient is presented for two types of RM electrons and holes, taking into account electron-like and hole-like densities of states. The paramagnetism and diamagnetism of the free RM electrons are simply explained using the definition of free RM electron density.

Evaluasi Kerusakan Jalan Berdasarkan Metode Surface Distress Index, Binamarga 1990, Serta Berbasis Software PKRMS

Baturono – Lamongan road is a distrit road that connects the districs of Sukodadi, Made, Lamongan. The road is an alternative road which is the main accesss so that there is a large volume of vehicles passing throught the road. Therefore, resulting in road damage that can interfere with user comfort and safety. This research to determine the type of road handling in accordance with the condition of the road damage. This esearch was carried out by means of primary data surveys in the form of LHR and road damage surveys. The methods used are Bina Marga 1990, Surface Distress Index (SDI), and PKRMS Software. On the Baturono road section ound the types of damage holes, pathces, transverse cracks, longitudinal, ruts, and alligator cracks. By using the Bina Marga method the priority order value is 10 including type of routine maintenance. The SDI methode yielded 37,85 &lt; 50 so that is included of routine maintenance. Meanwhile, software PKRMS output software obtained good results which included routine maintenance. The handling carried out refers to the practical manual of routine maintenance in the form of filling cracks, spreading sand, and closing crack.

Film Cooling Effectiveness on Pressure Surface and Suction Surface of Turbine Guide Vane With Diffusion Slot Holes

Abstract This paper investigated the film-cooling effectiveness of diffusion slot holes in a turbine nozzle guide vane. The pressure-sensitive paint measurement technique was employed to obtain the film-cooling effectiveness at a density ratio of DR = 1.5. The mainstream Reynolds number based on the axial chord length and the exit velocity was 6 × 105. The mainstream turbulence intensity was approximately 3.7%. Three diffusion slot hole geometries with cross-sectional aspect ratios (ASs) of 2.3, 3.4, and 4.9 were tested and compared with a typical fan-shaped hole. The experiments were performed at three typical hole row locations on the pressure surface (PS) and suction surface (SS). The average blowing ratios varied from M = 0.5 to 2.5. The results showed that throughout the blowing ratio range, on the PS, a substantially higher film-cooling effectiveness than the fan-shaped hole is always obtained from the diffusion slot hole with a large aspect ratio (AS = 4.9); on the SS, the diffusion slot hole with a small AS (AS = 2.3). The influence of hole row positioning is inconsistent for diffusion slot holes with different ASs. The diffusion slot hole is less affected by the PS when the AS is moderate and less affected by the SS when the AS is large. The film-cooling effectiveness of the diffusion slot holes is basically the lowest where the PS has a maximum concave curvature and the highest where the SS has a large favorable pressure gradient.

Analysis of disc brake with composite materials

While braking, frictional heat raise temperatures at the disc/pad interface. Due to which rotor's surface may experience early wear, thermally elastic instability, brake fluid vaporization, and thermally stimulated vibrations as a result of an excessive temperature increase brought on by frictional heat. In order to increase braking effectiveness and improve vehicle stability, an investigation on the use of various materials for the disc brake rotors of two different vehicle types, one of which is solid and the other of which is vented is carried out. The disc brake is modelled using modelling software CATIA and Finite element analysis (FEA) is carried out using ANSYS 14.5, the toolis able to analyse the temperature distribution, stress variation, and deformation over the rotor's profile of the disc brake rotor. After considering the impacts of temperature distribution, Vonmises stresses, and deformation. In this work analysis of disc brake is done with three materials (Aluminium Metal matrix composite, Mild steel and cast iron) used for vented with and without holes type disc brakes. Conferring to the results, Aluminium MMC is observed to be the optimum material for disc brakes where the deformation is minimum at mode shape 3 at frequency 597.1 Hz when compared to other mode shapes.

Experimental study on rockburst of surrounding rock in an elliptical tunnel with different axial ratios

The effect of the ratio of long and short axes on the rockburst of an elliptical tunnel structure was investigated by performing a series of true triaxial tests on red sandstone cuboid samples containing seven types of elliptical holes with different long–short axial ratios, using a self-developed true triaxial compression equipment. The entire process of spalling was monitored and recorded using a miniature camera. According to the test results, the failure stress, geometrical characteristics of the rockburst notch, fragment characteristics, and ejection velocity field characteristics of the rockburst are summarized, and the influence of the axial ratios of the elliptical hole on the failure characteristics and stability of the tunnel are discussed in detail. The test results indicate that the rockburst process of elliptical tunnels with different axial ratios experiences four processes; namely, calm period, small particle ejection period, spalling, and rockburst. The shape of the failure area after the rockburst presents a V-shaped feature. With the increase of the axial ratio, the area, angle, and depth of the V-shaped area show a decreasing trend, the initial failure stress of the cavern and the rockburst failure stress exhibit a trend of first decreasing and then increasing; the tangential stress of the cavern shows an increasing trend; the mass percentage of micro, fine, and medium grain decreases; and the average ejection velocity first decreases and then increases. Under the same stress conditions, rockbursts are more likely to occur on circular sections. Under the same section conditions, the ellipse can bear larger loads when its major axis is parallel to the disturbance stress. These conclusions are helpful to the efficient design of the tunnel structure.

High Sensitivity and Wide Range Refractive Index Sensor Based on Surface Plasmon Resonance Photonic Crystal Fiber.

In order to detect the refractive index (RI) of high refractive index materials such as trichlorobenzene and aniline in the near-infrared and mid-infrared spectra and expand the detection range of the refractive index, a surface plasmon resonance (SPR) photonic crystal fiber (PCF) sensor based on an elliptical sensing channel is proposed for high refractive index detection. The fiber core and the analyte channel are surrounded by two types of air holes with different sizes. When the surface plasmon resonance effect appears at the interface between the fiber core and the elliptical sensing layer, obvious resonance peaks appear in the near-infrared and mid-infrared bands. The full vector finite element method (FEM) is used to study the sensing characteristics of the sensor and the influence of structural parameters on the resonance peak. The results demonstrate that the sensor achieves detection in the refractive index range of 1.41-1.58, in the wavelength range of 1600-3200 nm. The average wavelength sensitivity is 9217.22 nm/RIU, and the refractive index resolution is 10.85 × 10-6 RIU. The proposed sensor realizes high refractive index detection in the near-infrared and mid-infrared bands, and obtains an ultra-wide detection range and higher sensitivity. The sensor has broad application prospects in chemical detection, biomedical sensing and other fields, and provides a theoretical reference for the design of a photonic crystal fiber surface plasmon resonance sensor.

Ideal HTLs May Open the Door for Further Development of Sb2Se3 Solar Cells—A Numerical Approach

Antimony selenide (Sb2Se3) material has been brought into sharp focus in the solar cell field due to its remarkable performance in recent times. Solar cell efficiency increases daily because of the excellent properties of Sb2Se3 material and progressive optimisation of each layer, especially the hole-transporting layer (HTL); it suppresses the recombination of the back surface and increases the built-in potential and efficiency. In this work, we used Sb2Se3 as an absorber layer and compared the behaviour of typical hole transport materials (HTMs) (Spiro-OMeTAD, CuSCN, and CuI) and their influence on device performance. The Sb2Se3 photovoltaic model with different HTMs was studied by SCAPS (version 3.3.10) software. Efficiency is highly influenced by light source and intensity. Thickness and defect density of the Sb2Se3 layer, the work function of the back contact, and series and shunt resistances also play an essential role in the better execution of solar cells. The performance of the device is enhanced when the transmission percentage increases at the front contact. The metalwork function must be 5 eV to attain a highly efficient PV cell, and after optimisation, CuI is the best HTM with a 23.48% efficiency.

Analysis of delamination and its effect on polymer matrix composites

The objective of this work is to evaluate the extension of the delaminated area around the hole obtained by machining and to correlate this damage with the loss of resistance of the material. For this purpose, two batches of specimens obtained from carbon/epoxide plates were tested, in which a hole was drilled at constant cutting speed and three different feed rates, as well as four tool options – helical MD, helical HSS, helical with pre-cutting hole and brad type. The specimens thus obtained were radiographed and from the resulting images it was possible to calculate the extent of the delaminated area. At the end, the specimens were mechanically tested – Pin-Bearing test – to obtain the proper correlation between damage extension and mechanical resistance. The results show that a relationship can be established between the delaminated area and the mechanical strength of the material, and that this decreases with the increase in the area of damage, making it possible to control the cutting variables to reduce the extent of this zone.

Design of a nanoscale gold-coated photonic crystal fiber biosensor

A simple two-layer refractive index sensor based on surface plasmon resonance has been proposed in this work, which evinces high sensitivity for detecting unknown analytes. This sensor design includes hexagonal- and octagonal-shaped air-hole rings, which have been introduced in the first and second layers, respectively. By performing this amalgamation of different types of air holes, this gold-coated plasmonic sensing scheme provides the broad sensing limit of the analyte, which is 1.32–1.40. The sensing performance has been examined by applying the finite element method, which is being used for modeling complex and irregular-shaped geometry. The wavelength interrogation method has demonstrated a maximal wavelength sensitivity of 9,000 nm/RIU (refractive index unit). The maximal amplitude sensitivity of 1902 RIU−1 has been exhibited in the y-polarized mode using the amplitude interrogation method. Moreover, the maximal sensor resolution of 1.11 × 10−5 RIU covers the entire sensing range. Furthermore, by adjusting the air-hole diameter, pitch, and depth of the gold layer coating, many more investigations have been demonstrated in this design. This highly sensitive sensor is very convincing to be used in many applications like chemical, biological, and also in physical sensing analyses.

Stabilization of α‐phase FAPbI3 via Buffering Interfacial Region for Efficient p–i–n Perovskite Solar Cells

AbstractFormamidinium lead triiodide (FAPbI3) with an ideal bandgap and good thermal stability has received wide attention and achieved a record efficiency of 26% in n–i–p (regular) perovskite solar cells (PSCs). However, imperfect FAPbI3 formation on the typical hole transport layer (HTL), high interfacial trap‐state density, and unfavorable energy alignment between the HTL and FAPbI3 result in the inferior photovoltaic performance of p–i–n (inverted) PSCs with FAPbI3 absorber. Herein, the α‐phase FAPbI3 is stabilized by constructing a buffer interface region between the NiOx HTL and FAPbI3, which not only diminishes NiOx/FAPbI3 interfacial reactions and defects but also facilitates carrier transport. Upon the construction of a buffer interface region, FAPbI3 inverted PSC exhibits a high‐power conversion efficiency of 23.56% (certified 22.58%) and excellent stability, retaining 90.7% of its initial efficiency after heating at 80 °C for 1000 h and 84.6% of the initial efficiency after operating at the maximum power point under continuous illumination for 1100 h. Besides, as a light‐emitting diode device, the FAPbI3 inverted PSC can be directly lit with an external quantum efficiency of 1.36%. This study provides a unique and efficient strategy to advance the application of α‐phase FAPbI3 in inverted PSCs.

Physical properties of the full Heusler-type Ru2-Fe NbAl (x = 0.00–0.50) alloys

We report the physical properties of a series of full Heusler-type Ru2-xFexNbAl (x = 0.00–0.50) alloys using magnetization, electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) measurements. Structure and phase analysis via x-ray diffraction and scanning electron microscopy indicate that Fe replaces the Ru in Ru2NbAl, and the antisite disorders reduce. The dc magnetization shows predominantly paramagnetic behavior for all Fe-doped samples, as in the pristine Ru2NbAl sample. Interestingly, the electrical resistivity measurements reveal that the conduction behavior of Ru2NbAl alloy changes from semiconducting-like to metal-like with Fe substitution. In addition, a minimum in resistivity at low temperatures is observed in the Fe-doped samples. It is noted that the minimum shifts to low temperatures with Fe content, presumably due to the weak localization effect. The Seebeck coefficient measurements show that charge carriers of these alloys remain hole type with a maximum S value of ∼27 µV/K at 300 K for x = 0.13, a result of the modification of the electronic band structure. The Fe substitution is found to reduce thermal conductivity significantly. An analysis of the lattice thermal conductivity indicates that the reduction in κ is primarily due to more grain boundaries, Umklapp phonons, and electron scatterings. These observations lead to an increase in the thermoelectric performance, i.e., the figure of merit and power factor, to about 0.007 and 1.7 μW/cm K2 at 300 K for the optimized composition of Fe with x = 0.13.

Types and State-of-art Detection Paradigms of Black Holes

Contemporarily, mankind has been exploring the universe for a long time, as early as 1609 when Galileo started to observe the closer planets with telescopes. The universe has an indispensable and extremely important object of study, which is the black hole, a celestial body whose curvature of space-time reaches the point where light cannot escape. The paper selects black holes as the investigation target discussing from the following aspects. Primarily, the basic description of black holes will be given. Then, we present several characteristics and several types of black holes and explain their importance in the universe Subsequently, detection paradigms for the black holes will be discussed and analyzed. The significance of our study is to reflect the efforts and efforts of human beings in exploring the universe, and to study the mysterious object of black holes. According to the analysis, it is believed that in the future, after several generations of efforts and exploration, and the upgrade of technology, human beings will have a deeper understanding of the universe and the secrets of black holes will no longer exist. These results shed light on guiding further exploration regarding to black holes.

Astrophysical observables for regular black holes with sub-Planckian curvature* *Supported in part by the Natural Science Foundation of China (11875053, 12035016). It is also supported by the Beijing Natural Science Foundation (1222031), and the Sichuan Youth Science and Technology Innovation Research Team with (21CXTD0038), Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province with (2021ZYD0032)

We investigate the photon sphere and marginally stable circular orbit of massive particles over the recently proposed regular black holes with sub-Planckian curvature and a Minkowskian core. We derive the effective potential for geodesic orbits and determine the radius of circular photon orbits, with an analysis of the stability of these orbits. We extend our analysis to the background of a compact massive object (CMO) without a horizon, whose mass is below the lowest bound for the formation of a black hole. For massive particles, marginally stable circular orbits become double-valued in the CMO phase. Through a comparison with Bardeen and Hayward black holes, we also find that the locations of the photon sphere and marginally stable circular orbit in the CMO phase with a Minkowskian core are evidently different from those in the CMO phase with a dS core, which potentially provides a way to distinguish between these two types of black holes by astronomical observation. Finally, we present the observational constraint on the deviation parameter for such regular black holes using observed data from the black hole M87*.

The Covariation of Color and Orange Fluorescence Instabilities in Yellow Sapphires

In recent years, some sapphires were found to fade in sunlight and to increase their color after UV irradiation. This unstable color phenomenon is attributed to the photochromism of corundum. The photochromic effect seriously affects the grading and evaluation of sapphires, although its mechanism is still uncertain. Here, we performed a set of photochromic experiments on sapphire specimens using a 254 nm shortwave UV light source and a D65 light source (which simulates sunlight) to generate different color states exhibiting characteristic absorption, emission, and excitation spectra. We observed that, for different color states, variation in the intensity of the absorption band at ~460 nm was consistent with that of orange fluorescence at 500–800 nm. This observation indicates a relationship between color instability and orange fluorescence. Peaks in excitation spectra at 320, 420, 490, 560, and 637 nm provide insight into the source(s) of excited orange fluorescence, which are related to different types of F-centers and Mg-trapped holes. We propose an explanation for the photochromic phenomenon: the color of photochromic yellow sapphire is the result of a variety of defects that release orange fluorescence simultaneously. Further, we hypothesize that the mechanism of photochromism in yellow sapphires is linked to electron transfer between F-centers and Mg-trapped holes.

Characteristics of Butane Combustion in Mesoscale–Combustor Due to Stainless Steel Flame Holder Type

Mesoscale–combustor is one component of the micropower generator. The mesoscale–combustor function is to produce heat energy from the combustion of chemical hydrocarbon compounds. The small dimensions of the meso-combustor cause large losses and short residence times for the reactants. These two factors lead to narrow flame flammability limits. This study aims to increase flammability limits by lengthening the reactant residence time and increasing reactant mixing with inserts of flow retardants called flame holders. There are two kinds of flame holders used in this study, namely holes and lines. Lines type produces flames at an equivalent ratio of Φ0.83–1.76 and speeds of 17.01 cm/s to 72.93 cm/s, while holes type produces flames at an equivalent ratio of Φ0.91–1.71 and a flow rate of 24.94 cm/s to 54.95 cm/s. This phenomenon shows that the line type flame holder is able to inhibit flow better and form vortices better, thereby increasing heat recirculation, flame stability, and widening flammability limits.