bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of New Composites Nano-Catalysts for Naphtha Reforming Process: Experiments and Process Modeling
Authors: Jarullah Aysar T. , Ahmed Ahmed Nabeel , Ahmed Ban Abdulrahman , Ahmed Abdullah M.
Published: May 2023

The naphtha catalytic reforming process is evaluated by designing new composite nano-catalysts. Three catalysts were prepared for this process. The first catalyst was molybdenum carbide composite with platinum over HY zeolite (Mo2C.Pt/HY zeolite), the second catalyst was molybdenum carbide composite with platinum over modified zeolite by cerium nitrate (Mo2C.Pt/CeY zeolite), and the last catalyst was bimetallic titanium and platinum with a titanium content of 1% and platinum content of 0.11% over HY zeolite (Pt.Ti/HY zeolite). All catalysts were tested with several tests, mainly X-Ray Diffraction (XRD), BET surface area, and pore volume. All these substances were applied as catalysts for the reforming process of Iraqi heavy naphtha at the following operating conditions: reaction temperature (480, 500, and 520 ), reaction pressure (10, 12.5, and 15 bar), liquid hourly space velocity (LHSV) at 2 hr-1, and constant hydrogen to hydrocarbon ratio (H2/ HC) of 4. All the reforming reactions occurred in a packed bed pilot plant reactor to investigate its stability and activity during the reforming process. All the developed catalyst samples showed sensational stability even at operating under difficult circumstances. The best catalyst was Pt.Ti/HY zeolite based on the results obtained with respect to the octane number (86.2) at 520  and 15 bar. Also, a mathematical model to describe the reforming process with high accuracy was built and simulated using gPROMS software. The results were very satisfying since the most significant error with the wt% of reformate was 4.9% (the experimental aromatics content was 23.94 wt.%, while the predicted result was 21.67 wt.%), while Research Octane Number (RON) error was 4.7% (the experimental RON was 81, whereas the predicted value of RON was 85) among all the results meaning that the simulating was valid to describe the process.
Impact of Joint Parameters on Performance of Self-Opening Dual-Matrix Composites
Authors: White Charles , Firth Jordan , Pankow Mark
Published: May 2023

Origami-based structures have expanded in recent years due to new mathematical formulations along with materials that can achieve the bending requirements, often in the form of composites. While current methods of manufacturing can produce complex structures, they lack the ability to scale efficiently. A novel manufacturing technique is discussed in this work that allows for a simpler and lower cost fabrication that can scale to larger structures through robotic deposition. Samples made from this technique are investigated to understand the mechanical bending performance and effect on the tensile properties. Results show an orientation-dependent response for the material with the 45° samples having a direct impact on the tensile response. However, their bending response proved to be stiffer compared to the [Formula: see text] samples, holding more consistent bend radii. Joint stacking was also investigated, where discrete layers were not bonded together and showed an increase in force required to bend compared to the completely bonded samples. The results provide insight into how integrated composite hinges can perform in complex structures. The advancement of composite origami technology additionally works to reduce the overall number or parts and fasteners that are needed to achieve detailed deployable structures.
Methods to Detect Impact-Induced Orbit Perturbations Using Spacecraft Navigation Data
Authors: Bennett Anne Aryadne , Carpenter Russell , Schaub Hanspeter
Published: May 2023

Debris strikes on operational spacecraft are becoming more common due to increasing numbers of space objects. Sample return missions indicate hundreds of minor strikes, but rigorous analysis is often only performed when a strike causes an anomaly in spacecraft performance. Developing techniques to identify and assess minor strikes that do not immediately cause anomalous behavior can help to validate models for debris populations and aid in the attribution of future anomalies. This study develops methods to detect subtle abrupt orbit perturbations indicative of minor debris strikes. An extended Kalman filter with dynamic model compensation is used to estimate a spacecraft’s orbit state based on simulated full-state (i.e., GPS) measurements. The filter is applied to the data forward and backward in time, and then a modified Fraser–Potter smoother is used to produce a fused state estimate. Various test statistics are developed and compared to identify abrupt unexpected changes in spacecraft velocity; techniques include McReynold’s filter-smoother consistency test and the Mahalanobis distance between forward and backward filter states. A trade study is performed to investigate the performance of test statistics as a function of filter parameters, and a Monte Carlo analysis illustrates the filter’s ability to detect and estimate strikes.
Dual-Altitude Band Coverage for Spaceborne Optical Sensor with Field-of-View Constraint
Authors: Sun Yangyuxi , Wen Changxuan , Zhu Zhengfan , Zhang Chen
Published: May 2023

Space-based optical monitoring systems have become promising options for space situational awareness with their advantages of observation range, duration, and quality. The dual-altitude band coverage evaluation of optical sensors is fundamental to designing and optimization of such systems. In this study, the dual-altitude band coverage evaluation of a spaceborne optical sensor with a cone field-of-view (FOV) constraint is addressed. Specifically, the target dual-altitude band region is discretized into crescent-shaped volume cells by introducing equidistant nodes along the radial and azimuth directions. When the size of each cell becomes sufficiently thin, the coverage of this cell can be approximated by the coverage of its centerline. Thus, the original dual-altitude band coverage problem is converted into a one-dimensional zenithal angular coverage problem. Then, considering geometric constraints on Earth’s occlusion and thermal background and the cone FOV constraints, we obtained the effective coverage of the azimuthal and zenithal angles of the target region by performing a comprehensive analysis of all 14 possible geometric cases. Alongside a pure coverage volume scoring method, a weighted coverage scoring method is introduced to take account of the nonuniform density distribution of space objects in altitude. Finally, the accuracy of the proposed method is validated by numerical examples.
Long-Duration Test of Coaxial Low-Energy Surface Flashover Ignitor
Authors: Zhang Yunping , Organski Lee , Shashurin Alexey , Ostrikov Kostya (Ken)
Published: May 2023

A coaxial low-energy surface flashover (LESF) ignitor for CubeSat electric propulsion systems was developed and tested. The ignitor features a coaxial geometry with copper electrodes directly bonded to the inner and outer surfaces of the alumina ceramic tubular insulator. The ignitor proved to be operational throughout (and after) an extended duration test of 10 million pulses. Characterization of a single LESF event via intensified charge-coupled device fast photography showed that the initial plasma was generated along the insulator surface, while the later plasma production was governed by the column attached to the copper electrodes. The plasma plume propagated primarily perpendicular to the insulator surface at around [Formula: see text]. Further investigation on the erosion of ceramic insulator and copper electrodes via energy-dispersive x-ray spectroscopy analysis of a witness plate exposed to LESF and scanning electron microscopy observation of the electrodes revealed that the ceramic erosion ([Formula: see text] molecules per pulse) was predominant over electrodes erosion ([Formula: see text] atoms per pulse or [Formula: see text]).
Conceptual Design of a Nonconstant Swept Flying Wing Unmanned Combat Aerial Vehicle
Authors: Aleisa Hassan , Kontis Konstantinos , Pirlepeli Berkay , Nikbay Melike
Published: May 2023

The design of unmanned combat aerial vehicles (UCAVs) is primarily governed by the low-observability requirement for military applications rather than aerodynamic performance. The conceptual design and optimization of UCAV models via size and shape variables for different missions in different flow regimes form a research area for military vehicle design. Flying wing UCAVs experience flow separation during takeoff and landing, and furthermore exhibit stability issues. The aerodynamic performance of these UCAVs can be significantly improved by redesigning their leading-edge sweep angle and wing planform. In the present work, the initial weight determination, aerodynamic sizing, and planform with and without inlet lip integration, and the conceptual design of a nonconstant leading-edge flying wing UCAV configuration are performed. Next, the obtained conceptual design is downscaled 1:20 to be used as a wind-tunnel model and optimized for low-speed conditions using a kriging-based surrogate model with a vortex-lattice method to maximize the lift-to-drag ratio. Later, the optimized design is validated using an open-source computational fluid dynamics code, OpenFOAM 8.0, to verify the accuracy of the surrogate model and to investigate the aerodynamic characteristics. The optimized UCAV design exhibited improved aerodynamic characteristics in terms of the lift-to-drag ratio. Furthermore, the aerodynamic performance and flowfield of the optimized UCAV model with and without inlet lip integration have been evaluated at low and high speeds.
Predicting the Number of Fatalities in Extreme Civil Aviation Accidents
Authors: Huesler Joel , Strobl Eric
Published: May 2023

This study estimates the probability of extreme fatalities from civil airplane accidents in the United States since the early 1980s. To this end, extreme civil airplane accidents were modeled using extreme value statistics, allowing for changes in the distribution due to other factors. The analysis revealed that an extreme aircraft accident causes 18 to 20 fatalities every two years with costs between 111.6 and 124 million U.S. dollars (USD); whereas accidents with (at least) between 70 and 100 fatalities will occur every 20 years, costing between 424 and 620 million USD. The findings also indicate that higher volumes of air traffic increase the return levels of severe aviation accidents, whereas higher ticket prices reduce the likelihood of these. The findings emphasize the serious consequences of airplane accidents with respect to the number of fatalities but also how these depend on market conditions.
Dual-Quaternion-Based Dynamics Modeling for a Rigid–Flexible Coupling Satellite
Authors: Wang Peidong , Wang Tianshu , Sun Jun , Zhang Xianliang , Song Ting
Published: May 2023

Dual quaternions can describe both three-dimensional translation and three-dimensional rotation and have the advantages of a simple form, accurate modeling, and precise physical meaning in terms of dynamic modeling. The traditional rigid-body dynamics modeling theory based on dual quaternions is only applicable to the case of modeling for the center of mass. When modeling appendages, the flexible appendages must be symmetrically configured to reduce the modeling complexity. However, in space operations, flexible appendages are usually not symmetrically installed, which significantly limits the applications of dual-quaternion theory. In this paper, we propose a new dual-quaternion derivative rule and a rigid-body dynamic modeling method suitable for any point. The theory can be applied to model flexible appendages with any configuration without changing the mathematical modeling framework. Finally, we demonstrate the integrated dynamic equation of a rigid–flexible coupling system considering the coupling of position and attitude, and we verify the correctness of the model by numerical simulation.
Deep Space Navigation by Optical Pulsars
Authors: Zoccarato Paolo , Larese Samuele , Naletto Giampiero , Zampieri Luca , Brotto Francesca
Published: May 2023

Nowadays, deep-space navigation strongly depends on ground segments, e.g., ESA’s European Space Tracking and NASA’s Deep Space Network. However, the positioning accuracy of ground-based navigation systems decreases with the distance from the Earth, significantly increasing the positioning uncertainty for interplanetary missions. Furthermore, ground-based navigation systems require extensive ground operations, and their limited bandwidth could lead to a point of full utilization in the future. The aim of this work is to introduce—for the first time—the concept of space navigation by optical pulsars, a novel technology that aims at overcoming the limits of ground-based navigation systems. This paper presents, first, an introduction to satellite navigation by using pulsars, discussing on the physical and timing properties of optical pulsars. Then, it investigates on the timing techniques allowing to reconstruct, process, and make use of a pulsar signal, leading to a position estimation. Finally, it reports the results of a clock error estimation performed on ground with real pulsar data and a first estimation of the achievable positioning accuracy in a simulated highly elliptical orbit around the Earth.
Adaptive Finite Time Intercept Guidance
Authors: Calise Anthony J.
Published: May 2023

This paper summarizes several key issues of importance related to intercept of high-speed maneuvering targets under stratospheric altitude conditions, where it is unlikely that the interceptor will have a significant speed and/or maneuverability advantage. It explains why one cannot rely on traditional proportional navigation guidance and presents simulation results for a recently developed finite time method of guidance. A simplified version of finite time intercept guidance is derived, and a modification required to allow it to be practically implemented is described. Simulation results are presented to illustrate the advantages of the simplified version.
New Viewpoint on the Mechanism of Laminar Separation Flutter
Authors: Lyu Zhen , Lim H. D. , Zhang Weiwei
Published: May 2023

At transitional Reynolds numbers, an elastically supported airfoil oscillating in pitch can undergo laminar separation flutter (LSF), which is characterized by self-sustained small-amplitude oscillations. To gain insight into the mechanism of LSF, we conduct wind tunnel tests for [Formula: see text] to investigate the LSF response of a freely rotating NACA0015 airfoil with various structural natural frequencies and positions of the elastic axis. The experimental results show that the dominant mode of flow around the NACA0015 airfoil abruptly changes at [Formula: see text], resulting in a change in the trend of LSF response. Then, an aeroelastic model is constructed to explain how the instability of LSF arises. This model can accurately predict the LSF frequency of airfoils with various structural natural frequencies. Moreover, based on the aeroelastic model, we perform linear stability analysis on the aeroelastic system and propose the instability criterion for LSF as [Formula: see text]. This instability criterion is identical to that for rotational galloping of square cylinder, indicating that LSF and rotational galloping of square cylinder are essentially the same aeroelastic phenomenon that appears in different aerodynamic profiles. This finding identifies the underlying cause for the remarkable similarities between the two phenomena.
Analysis of Sputtering Yield Measurements for Ion Thruster Grid Materials
Authors: He Zihao , Miao Long , Zhu Zhengxi , Liang Fuwen , Song Jiahui , Wang Ningfei , Hou Xiao
Published: May 2023

Grid assembly is one of the key components of an ion thruster and directly affects the performance and life of the thruster. The measurement of the sputtering yield of the grid assembly under ion beam bombardment is highly significant for predicting the lifetime of the grid assembly and ion thruster. This study systematically summarizes the main methods currently used for sputtering yield measurement of grid materials, analyzes the advantages and disadvantages of different measurement methods, and provides suggestions for sputtering yield measurements in the low-energy ([Formula: see text]) range. In addition, this study compares the sputtering resistance properties of metal- and carbon-based grid materials and summarizes the influence of key core parameters, such as the surface roughness, surface morphology, binding energy, and incident angle, on the sputtering yield. The results can be used to guide the correction of the sputter yield theoretical formula and the numerical simulation of sputtering erosion.
Experimental Analysis of Transonic Buffet Conditions on a Two-Dimensional Supercritical Airfoil
Authors: Schauerte Christopher Julian , Schreyer Anne-Marie
Published: May 2023

The present experimental investigation characterizes the development and decay of transonic buffet on the supercritical airfoil OAT15A, as well as the flow field and shock motion throughout the fully developed buffet cycle. A comprehensive database of high-speed focusing schlieren sequences provides access to the temporal and spectral behavior of the oscillatory shock motion within a broad parameter space, covering Mach numbers 0.68–0.80 and angles of attack 3.3–6.5 deg. From these data, multiple temporal and spectral properties characterizing the distinctness of the shock oscillation are extracted. Combining these indicators enables us to clearly distinguish fully established buffet from pre-buffet, buffet onset, and buffet offset. This criterion helps to interpret the diverse findings in the relevant literature cases. Particle-image velocimetry measurements provide detailed insight into the turbulence structure and behavior throughout a fully established buffet cycle at a Mach number of 0.72 and an angle of attack of 5 deg. Instantaneous and phase-averaged velocity maps indicate massive flow separation for shock positions close to the upstream limit. Velocity profiles illustrate the large intermittent velocity deficit persisting until the trailing edge and corroborate most pronounced separation when induced by an upstream-traveling shock wave. Representative phases of the buffet cycle visualize and quantify the severe modification of the flow topology modulated by the shock and lay the groundwork to improve the understanding of mechanisms governing shock buffet.
Stochastic Framework for Optimal Control of Planetary Reentry Trajectories Under Multilevel Uncertainties
Authors: Wang Zhiheng , Ghanem Roger
Published: May 2023

We present a novel stochastic optimal control framework that accounts for various types of uncertainties, with application to reentry trajectory planning. The formulation of the optimal trajectory control problem is presented in the context of an indirect method where a functional objective associated with the terminal vehicle speed is to be minimized. Uncertain input parameters in the optimal trajectory control model, including aerodynamic parameters and initial and terminal conditions, are modeled as aleatory random variables, while the statistical parameters of these aleatory distributions are themselves random variables. The parametric and model uncertainties are simultaneously propagated through an extended polynomial chaos expansion (EPCE) formalism. Several metrics are described to evaluate response statistics and presented as insightful tools for robust decision making. Specifically, the response probability density function (PDF) reflecting influence of both epistemic and aleatory uncertainties is obtained. By sampling over the random variables representing model error, an ensemble of response PDFs is generated and the associated failure probability is estimated as a random variable with its own polynomial chaos expansion. Besides, the sensitivity index functions of response PDF with respect to the statistical parameters are evaluated. Coupling parametric and model uncertainties within the EPCE framework leads to a robust and efficient paradigm for multilevel uncertainty propagation and PDF characterization in general optimal control problems.
Pneumatic-Probe Measurement Errors Caused by Fluctuating Flow Angles
Authors: Coull John D. , Ng Henry C.-H. , Dickens Tony , Serna José , Cengiz Kenan
Published: May 2023

Pneumatic probes such as five-hole probes (5HP) can conveniently measure three-dimensional flow angles, plus total and static pressure. In most applications, transducers are connected using pneumatic tubes, allowing the probe head to be highly miniaturized and robust. However, such “steady” probes are often used in unsteady flows, where they measure a pneumatically averaged flowfield that can differ from the time mean. To better understand these pneumatic averaging effects, an analytical framework is constructed using a quasi-steady model. Total and static pressure coefficients have a symmetric response to both positive and negative incidence. When incidence fluctuates, there is therefore a bias in the pneumatic average. These errors are evident in a shedding wake experiment, where a 5HP overestimates total pressure loss by up to 44% compared to a Kiel probe. These effects can be predicted by coupling an unsteady Reynolds-averaged Navier–Stokes calculation with the quasi-steady model. By predicting pneumatic averaging errors, the quasi-steady model can be used to obtain like-for-like validation of calculations against experimental data. Measurement data can also be corrected, provided that flow angle fluctuations can be measured or estimated. This approach can be readily used to postcorrect the large body of historical data likely to have been corrupted by pneumatic-averaging errors.
Vortex Interaction Characteristics of Multiswept Wings at Subsonic Speeds
Authors: Ghoreyshi Mehdi , Fagley Casey , Seidel Jürgen
Published: May 2023

Despite the sufficient knowledge on the physics of vortices formed over slender delta wings, there is a lack of understanding about how corotating and counter-rotating vortices near the wing leading edge interact with each other. The vortex interaction will depend on the wing planform, leading-edge sweeps, leading-edge shapes, angle of attack, angle of sideslip, and the Reynolds number. In this study, experiments were performed on a range of planform configurations to determine the influence of multisweep wing configurations on the vortex interactions and breakdown thereof. Force/moment measurements were conducted to understand globally the effect of the planform configuration, whereas particle tracking surface oil flow and stereoscopic particle image velocimetry were employed to detect interactions locally in the flowfield. Results were validated against corresponding numerical simulations and past experiments. Comprehensive results indicated a strong correlation between the chord ratios of the initial sweep on the suppression of vortex breakdown. Specifically, two cases with varying chord ratios were identified that exhibited unique vortex breakdown progression (gradual and rapid). Flowfield measurements elucidated key flow features responsible for the differing breakdown progression.
Learning Neural-Network-Based Turbulence Models for External Transonic Flows Using Ensemble Kalman Method
Authors: Liu Yi , Zhang Xin-Lei , He Guowei
Published: May 2023

This paper presents a neural-network-based turbulence modeling approach for transonic flows based on the ensemble Kalman method. The approach adopts a tensor-basis neural network for the Reynolds-stress representation, with modified inputs to consider fluid compressibility. The normalization of input features is also investigated to avoid feature collapsing in the presence of shock waves. Moreover, the turbulent heat flux is accordingly estimated with the neural-network-based turbulence model based on the gradient diffusion hypothesis. The ensemble Kalman method is used to train the neural network with the experimental data in velocity and wall pressure due to its derivative-free nature. The proposed framework is tested in two canonical configurations, that is, two-dimensional transonic flows over the RAE2822 airfoils and three-dimensional transonic flows over the ONERA M6 wings. Numerical results demonstrate the capability of the proposed method in learning accurate turbulence models for external transonic flows.
Two-Temperature Modeling of Nonequilibrium Relaxation and Dissociation in Shock-Heated Oxygen
Authors: Aiken Timothy T. , Boyd Iain D.
Published: May 2023

Two-temperature models for coupled vibrational relaxation and dissociation in shock-heated oxygen are assessed using low-uncertainty measured data from reflected shock tube experiments. A computationally efficient multistep technique is developed to model the unsteady dynamics of shock reflection in a relaxing and dissociating gas. The developed technique is then benchmarked through comparison with unsteady computational fluid dynamic simulations. Results from the benchmarking effort demonstrate that the adopted multistep modeling procedure accurately captures the dominant gas dynamic effects influencing the state of the test gas at the measurement location. A parametric study is then performed to assess several combinations of possible two-temperature modeling approaches for nonequilibrium oxygen dissociation. The current assessment demonstrates that the widely adopted Park model is inconsistent with the measured data, while the recently developed modified Marrone and Treanor (MMT) model demonstrates promising agreement with the data. The results of the present study clearly indicate that the MMT model is more appropriate for two-temperature modeling of nonequilibrium oxygen dissociation than the legacy Park model. Patterns in the parametric comparison also suggest that the approximate treatment of non-Boltzmann vibrational state distributions within the MMT model may require improvement.
Measurements and Modeling of Air Plasma Radiation in the VUV
Authors: McGuire Sean D. , Jacobs Carolyn , Mariotto Pierre B. , Grimaldi Corentin H. C. , Tibère-Inglesse Augustin , Laux Christophe O.
Published: May 2023

Measurements of high-temperature air emission spectra between 150 and 250 nm (VUV/UV) are presented. These measurements are calibrated in absolute intensity. The high-temperature air was produced using an atmospheric pressure plasma torch facility. The centerline temperature of the plasma jet is approximately 6700 K. A VUV emission spectroscopy system was adapted to the plasma torch facility to acquire spectra from 150 to 250 nm. Absolute intensity spectra were obtained in this wavelength range. They were compared with numerical predictions of the line-by-line spectroscopy code SPECAIR. The overall agreement between the SPECAIR predictions and measurements is good, particularly above 180 nm. Several modifications to the SPECAIR radiation code were carried out in order to improve agreement with experiments. These modifications significantly improved agreement though, at lower wavelengths, the data indicate that a source of emission remains unaccounted for by SPECAIR. Several possibilities for this missing source of emission are discussed, including photodissociation of the nitric oxide molecule.
Petrol Fiyatlarındaki Dalgalanmaların Türkiye Ekonomisi Üzerine Etkileri: Asimetrik Testlerden Kanıtlar
Authors: ŞENGÜL Oğuzhan
Published: May 2023

Gelişmekte olan ekonomilerde enerji ihtiyacı büyüme ile birlikte artarak devam etmektedir. Bu bağlamda petrol fiyatlarındaki değişim bu ülkelerin makro ekonomik göstergeleri üzerinde farklı etkiler bırakmaktadır. Bu durum enerji bağımlı ekonomilerde daha da önemli hale gelirken, petrol ihracatçısı ülkeler için farklı senaryolar ortaya çıkabilmektedir.

Bu çalışmada gelişmekte olan bir ekonomilerden biri olan Türkiye ekonomisinde 2000 – 2021 yılları arasında kalan dönemde petrol fiyatlarında yaşanan şokların Türkiye’nin ekonomik büyüme performansı üzerindeki etkisi incelenmektedir. Çalışmada, petrol fiyatlarındaki pozitif ve negatif şokların etkilerinin tam olarak anlaşılabilmesi için asimetrik sınır ve nedensellik testleri kullanılmaktadır. Sonuçlar göstermektedir ki, petrol fiyatları ile ekonomik büyüme arasında asimetrik bir ilişki bulunmaktadır. Petrol fiyatlarındaki artışlar Türkiye ekonomisini petrol fiyatlarındaki düşüşten daha fazla etkilemektedir.
2008 Küresel Ekonomik Krizi ve Türkiye’de Sektör Karlılığı
Authors: ÇAKMAK İsmail , ÖZTÜRK Selcen
Published: May 2023

2008 küresel ekonomik krizi, Dünya’nın son dönemde yüzleştiği en büyük ekonomik olaylardan birisidir. Finansal kesimde başlayan kriz, yayılmacı ve bulaşıcı etkisi ile kısa sürede az gelişmiş, gelişmekte olan ve gelişmiş ekonomilerin reel sektörlerine de sıçrayarak bütüncül bir ekonomik kriz halini almıştır. Bu çalışmanın amacı, 2008 krizinin Türkiye’de faaliyet gösteren sektörlerin kârlılıklarına olan etkisini analiz etmektir. Çalışmada ayrıca, kriz döneminde kârlılığa hangi faktörlerin etki ettiği ve yapılan forecasting (tahmin) analizi ile kriz olmasa idi sektör kârlılıkları nasıl seyrederdi sorularına da cevap aranmıştır. Çalışmanın sonucunda 2006-2014 arası dönemde faktör maliyet ile katma değer, ihracat, yurt içi satışlar ve kambiyo kârının sektör kârlılıklarını anlamlı ve pozitif etkilediği, bunun yanında başta imalat sanayi olmak üzere inşaat ve ulaştırma sektörlerinin ise krizden anlamlı derecede etkilendiği tespit edilmiştir. Kriz etkilerinin minimize edilmeye çalışıldığı sonraki yıllarda ise uygulanan politikalar ile sektör kârlılıklarının toparlanma eğilimine girdiği ve hatta beklenen kârlılığın üzerine çıktığı görülmüştür.
Remittances and Life Satisfaction of Immigrants Living in Istanbul
Authors: GÜL Songül , GÖKDEMİR DUMLUBAĞ Özge
Published: May 2023

The immigrant remittances emerged due to the international migration occupy an important place especially in the economies of developed and underdeveloped countries along with their serious contributions. In addition to their macro level importance these remittances sent to family members for various reasons cause also important transformations in the socio-economic structure of society. This study aims to analyse the effect of sending remittance on immigrants’ life satisfaction. The surveys were conducted face-to-face with 1006 immigrants living in Istanbul and the responses were analysed using the OLS analysis method. The questions in the survey were prepared in English and in Turkish. Immigrants who are a part of the study are people who have legally obtained a residence permit in Turkey. The dependent variable in this study was “All things considered, how satisfied are you with your life as a whole these days?” It is life satisfaction, which consists of individual answers to the question. Participants were asked to rate on a ranking scale ranging from 0 (not at all satisfied) to 10 (completely satisfied. People from 89 different countries took part in the study. Results indicate that sending remittance reduces people’s happiness. People who have left their country due to economic conditions are observed to be more unhappy. On the other hand savings make people happier. In addition people who think that their financial status is better after the migration are happier than others.
DAMPAK IMPLIKASI SISTEM INFORMASI MANAJEMEN BAZNAS (SIMBA) PADA AKUNTABILITAS PENGELOLAAN ZAKAT DI KABUPATEN PROBOLINGGO
Authors: Mukarromah Lailatul , Widya Prasetyandari Cici
Published: May 2023

BAZNAS merupakan suatu lembaga badan amil zakat  nasional yang bertugas untuk menghimpun serta menyalurkan dana zakat kepada masyarakat yang berhak menerima. Penelitian ini bertujuan untuk mengetahui bagaimana pengaruh Sistem Informasi Manajemen BAZNAS (SIMBA) terhadap pengelolaan zakat di BAZNAS Kabupaten Probolinggo. Karena dalam penelitian ini hanya terdapat dua variabel terikat dan satu variabel bebas, maka strategi yang digunakan dalam penelitian ini  adalah analisis regresi linier sederhana dan menggunakan analisis koefisien korelasi sederhana untuk memastikan seberapa besar hubungan antara kedua variabel tersebut. dan instrumen dalam program Statistical for the Social Sciences (SPSS). Sistem Informasi Manajemen BAZNAS (SIMBA), dari rancangan penelitian ini dapat menghasilkan bahwa dampak Implikasi Sistem Informasi Manajemen BAZNAS (SIMBA) terhadap pengelolaan zakat di BAZNAS Kabupaten Probolinggo belum sepenuhnya berpengaruh. Hal ini terlihat dari hasil penelitian yang menunjukkan bahwa implikasi SIMBA berdampak pada penghimpunan zakat sebesar 21,1% dan pendisdistribusian zakat sebesar 16,2%, sedangkan sisanya berdampak pada variabel lain sebesar 62,7%.
The natural lift of the fixed centrode of a non-null curve in Minkowski 3-space
Authors: Mustafa Çalişkan  , Evren Ergün
Published: May 2023

In this study, we dealt with the natural lift curves of the fixed centrode of a non-null curve.Furthermore, some interesting result about the original curve were obtained, depending on the assumption that the natural lift curves should be the integral curve of the geodesic spray on the tangent bundle $T\left(S_1^2\right)$ and $T\left(H_0^2\right)$.
Certain properties of a subclass of harmonic convex functions of complex order defined by multiplier transformations
Authors: K. Thilagavathi  , K. Vijaya  , N. Magesh
Published: May 2023

In this paper, we investigate some properties of harmonic univalent functions of complex order using multiplier transformation.Such as Coefficient bounds, extreme points, distortion bounds, convolution conditions and convex combination are determined for functions in this family. Further, we obtain the closure property of this class under integral operator. Consequently, many of our results are either extensions or new approaches to those corresponding to previously known results.
Existence of solutions of q-functional integral equations with deviated argument
Authors: A. M. A. El-Sayed  , Fatma. M. Gaafar  , R. O. Abd-El-Rahman  , M. M. El-Haddad
Published: May 2023

In this paper, we study the existence of solutions for $q$-functional integral equations in Banach space $C[0, T]$. The existence and uniqueness of solutions for the problems are proved by means of the Banach contraction principle.
Reciprocal graphs
Authors: G. Indulal  , A.Vijayakumar
Published: May 2023

Eigenvalue of a graph is the eigenvalue of its adjacency matrix. A graph $G$ is reciprocal if the reciprocal of each of its eigenvalue is also an eigenvalue of $G$. The Wiener index $W(G)$ of a graph $G$ is defined by $W(G)=\frac{1}{2} \sum_{d \in D} d$ where $D$ is the distance matrix of $G$. In this paper some new classes of reciprocal graphs and an upperbound for their energy are discussed. Pairs of equienergetic reciprocal graphs on every $n \equiv$ $0 \bmod (12)$ and $n \equiv 0 \bmod (16)$ are constructed. The Wiener indices of some classes of reciprocal graphs are also obtained.
A generalization of natural density
Authors: R. Vembu  , A. Bowrna
Published: May 2023

The concept of natural density is generalized. It is proved that the new theory is consistent with the existing theory in the literature. Many new results were obtained. A theorem analogous to the Riemann’s theorem on rearrangement of non-absolutely convergent series is proved in the sense of generalized natural density. Some more possible generalizations are suggested.
Existence results for nonlinear fractional differential equation with nonlocal integral boundary conditions
Authors: Renu Chaudhary  , Dwijendra N Pandey
Published: May 2023

In this paper, we shall study a nonlinear fractional differential equation with nonlocal integral boundary conditions. We have used fixed point theorems and Laray-Schauder nonlinear alternative to study the existence and uniqueness of solutions to the given equation. In the last, we have given examples to illustrate the applications of the abstract results.
Interval criteria for oscillation of second-order impulsive delay differential equation with mixed nonlinearities
Authors: V. Muthulakshmi  , R. Manjuram
Published: May 2023

We obtain interval oscillation criteria for the second-order impulsive delay differential equation$$\begin{gathered}\left(r(t) \Phi_\alpha\left(x^{\prime}(t)\right)\right)^{\prime}+p(t) \Phi_\alpha(x(t-\tau))+\sum_{i=1}^n q_i(t) \Phi_{\beta_i}(x(t-\tau))=e(t), t \geq t_0, t \neq t_k \\x\left(t_k^{+}\right)=a_k x\left(t_k\right), \quad x^{\prime}\left(t_k^{+}\right)=b_k x^{\prime}\left(t_k\right), k=1,2,3, \ldots\end{gathered}$$The results obtained in this paper extend some of the existing results. We have given some examples to illustrate our results.
Semi-invariant submanifolds of a Kenmotsu manifold with a generalized almost r-contact structure admitting a semi-symmetric metric connection
Authors: Mobin Ahmad  , Abdul Haseeb  , Sheeba Rizvi
Published: May 2023

We consider an almost r-contact Kenmotsu manifold admitting a semi-symmetric metric connection and study semi-invariant submanifolds of an almost r-contact Kenmotsu manifold endowed with a semi-symmetric meric connection. We obtain Gauss and Weingarten formuale for such a connection and also discuss the integrability conditions of the distributions on a generalized Kenmotsu manifold.
Riemann-Liouville fractional Hermite-Hadamard inequalities for differentiable λϕ-preinvex functions
Authors: Sümeyye ERMEYDAN  , Hüseyin YILDIRIM
Published: May 2023

In this work, we demonstrate Hermite-Hadamard type inequalities for Riemann-Liouville fractional integrals via once differentiable and twice differentiable defined using λϕ-preinvex functions.
A note on global bipartite domination in graphs
Authors: A.R. Latheesh Kumar  , V. Anil Kumar
Published: May 2023

In this paper we introduce the concept of the global bipartite domination number $\gamma_{g b}(G)$ of a connected bipartite graph $G$ and study some of its general properties. Moreover we determine the global bipartite domination number of certain classes of graphs.
Erratum: Certain properties of a subclass of harmonic convex functions of complex order defined by multiplier transformations-Malaya J. Mat. 4(3)2016, 362-372
Authors: K. Thilagavathi  , K. Vijaya  , N. Magesh
Published: May 2023

In the paper entitled Certain properties of a subclass of harmonic convex functions of complex order defined by Multiplier transformations- Malaya J. Mat. 4(3)2016, 362-372, the presentation of definition of modified Multiplier transformation of harmonic function $f=h+\bar{g}$ as given below.$$\begin{gathered}I_\gamma^0 f(z)=D^0 f(z)=h(z)+\overline{g(z)} \\I_\gamma^1 f(z)=\frac{\gamma D^0 f(z)+D^1 f(z)}{\gamma+1} \\I_\gamma^n f(z)=I_\gamma^1\left(I_\gamma^{n-1} f(z)\right),\left(n \in N_0\right) \\I_\gamma^n f(z)=z+\sum_{k=2}^{\infty}\left(\frac{k+\gamma}{1+\gamma}\right)^n a_k z^k+(-1)^n \sum_{k=1}^{\infty}\left(\frac{k-\gamma}{1+\gamma}\right)^n b_k z^k\end{gathered}$$Also if $f$ is given, then,$$I_\gamma^n f(z)=f \widetilde{*} \underbrace{\left(\phi_1(z)+\overline{\phi_2(z)}\right) \widetilde{\ldots \ldots *}\left(\phi_1(z)+\overline{\left.\phi_2(z)\right)}\right.}_{n-\text { times }}=h * \underbrace{\left(\phi _ { 1 } ( z ) * \ldots \left(\phi_1(z)\right.\right.}_{n-\text { times }}+\overline{g+\underbrace{\left(\phi_2(z) * \ldots\left(\phi_2(z)\right)\right)}_{n-\text { times }}},$$where $*$ denotes the usual Hadamard product or convolution of power series and$$\phi_1(z)=\frac{(1+\gamma) z-\gamma z^2}{(1+\gamma)(1-z)^2}, \phi_2(z)=\frac{(\gamma-1) z-\gamma z^2}{(1+\gamma)(1-z)^2}$$is taken from the article by Yasar and S. Yalçin [1].
Caratheodory's theorem for \mathbb{B}^{-1}-convex sets
Authors: G. Adilov  , I. Yesilce
Published: May 2023

In this article, our main concept is $\mathbb{B}^{-1}$-convexity that is a new abstract convexity type. For the $\mathbb{B}^{-1}$-convex sets, Caratheodory's Theorem which is one of the most important results in convexity theory is proved and its corollary is given.
Fractional integral Chebyshev inequality without synchronous functions condition
Authors: Zoubir DAHMANI  , , Amina KHAMELI  , Karima FREHA
Published: May 2023

In this paper, we use the Riemann-Liouville fractional integrals to establish some new integral inequalities related to the Chebyshev inequality in the case where the synchronicity of the given functions is replaced by another condition. This paper generalises some recent results in the paper of [C.P. Niculescu and I. Roventa: An extension of Chebyshev’s algebraic inequality, Math. Reports, 2013].
An efficient modification of PIM by using Chebyshev polynomials
Authors: Mohamed M. Khader  , Amr M. S. Mahdy
Published: May 2023

In this article, an efficient modification of the Picard iteration method (PIM) is presented by using Chebyshev polynomials. Special attention is given to study the convergence of the proposed method. The proposed modification is tested for some examples to demonstrate reliability and efficiency of the introduced method. A comparison between our numerical results against the conventional numerical method, fourth-order Runge-Kutta method (RK4) is given. From the presented examples, we found that the proposedmethod can be applied to wide class of non-linear ordinary differential equations.
On the biordered set of rings
Authors: P. G. Romeo  , R. Akhila
Published: May 2023

In [4] K.S.S. Nambooripad introduced biordered sets as a partial algebra $\left(E, \omega^r, \omega^l\right)$ where $\omega^r$ and $\omega^l$ are two quasiorders on the set $E$ satisfying biorder axioms; to study the structure of a regular semigroup. Later in [2] David Esdown showed that the set of idempotents of a regular semigroup forms a regular biordered set. Here we extend the idea of biordered sets into rings and discussed some of its properties.
Zagreb indices of a graph and its common neighborhood graph
Authors: Dae-Won Lee  , Shaban Sedghi  , Nabi Shobe
Published: May 2023

A complete set of relations is established between the first and second Zagreb index of a graph and of its congraph. Formulas for the Zagreb indices of several derived graphs are also obtained.
$\theta $-local function and $ \psi_\theta$-operator
Authors: M. Anandhi  , C. Janaki
Published: May 2023

In this paper, we introduce the notion of a $\theta$-local function and investigate some of their properties. Also, we define two operators ()$^{* \theta}$ and $\psi_\theta$ in an ideal topological space.
Continuous dependence of the solution of a stochastic differential equation with nonlocal conditions
Authors: A. M. A. El-Sayed  , R. O. Abd-El-Rahman  , M. El-Gendy
Published: May 2023

In this paper we are concerned with a nonlocal problem of a stochastic differential equation that contains a Brownian motion. The solution contains both of mean square Riemann and mean square Riemann-Steltjes integrals, so we study an existence theorem for unique mean square continuous solution and its continuous dependence of the random data X 0 and the (non-random data) coefficients of the
On the maximal and minimal solutions of a nonlocal problem of a delay stochastic differential equation
Authors: A. M. A. El-Sayed  , F. Gaafar  , M. El-Gendy
Published: May 2023

In this paper we are concerned with a problem of of a delay stochastic differential equation with nonlocal condition, the solution is represented as stochastic integral equation that contain mean square Riemann integral. We study the existence of at least mean square continuous solution for this problem. The existence of the maximal and minimal solutions will be proved.
Coefficient estimates for Bazileviˇc Ma-Minda functions in the space of sigmoid function
Authors: Sunday Oluwafemi Olatunji  , Emmanuel Jesuyon Dansu
Published: May 2023

In this work, the authors investigated the coefficient estimates for Bazilevič Ma-Minda Functions for the class $T_n^\alpha(\lambda, \beta, l, \Phi)$. The first few coefficient bounds for this class were obtained and also the relevant connection to Fekete-Szegö theorem and were briefly discussed. Our results serve as a new generalization in this direction and gives birth to many corollaries.
Donoho-Stark uncertainty principle for the generalized Bessel transform
Authors: N. Safouane  , A. Abouleaz  , R. Daher
Published: May 2023

The generalized Bessel transform satisfies some uncertainty principles similar to the Euclidean Fourier transform. A generalization of Donoho-Stark uncertainty principle is obtained for the generalized Bessel transform.
Pseudo asymptotically periodic integral solution of partial neutral functional differential equations
Authors: Zhinan Xia
Published: May 2023

In this paper, we propose a new class of functions called $\mu$-pseudo $\mathcal{S}$-asymptotically periodic function on $\mathbb{R}$ by the measure theory. Furthermore, the existence, uniqueness of $\mu$-pseudo $\mathcal{S}$-asymptotically periodic integral solution to partial neutral functional differential equations with finite delay are investigated. Here we assume that the undelayed part is not necessarily densely defined and satisfies the Hille-Yosida condition.
Nondifferentiable augmented Lagrangian, ε-proximal penalty methods and applications
Authors: Noureddine Daili  , K. Saadi
Published: May 2023

The purpose of this work is to prove results concerning the duality theory and to give detailed study on the augmented Lagrangian algorithms and $\varepsilon$-proximal penalty method which are considered, today, as the most strong algorithms to solve nonlinear differentiable and nondifferentiable problems of optimization. We give an algorithm of primal-dual type, where we show that sequences $\left\{\lambda^k\right\}_k$ and $\left\{x^k\right\}_k$ generated by this algorithm converge globally, with at least the Slater condition, to $\bar{\lambda}$ and $\bar{x}$. Numerical simulations are given.
On the Cohen p-nuclear positive sublinear operators
Authors: A. Belacel
Published: May 2023

In the present paper, we will introduce the concept of Cohen p-nuclear positive sublinear operators. We give an analogue to “Pietsch’s domination theorem” and we study some properties concerning this notion.
Third Hankel determinant for certain subclass of analytic functions
Authors: M. A. Ganiyu  , K.O. Babalola
Published: May 2023

The third Hankel determinant, $H_3(1)$ for subclass of analytic functions satisfying geometric condition$$\operatorname{Re} \frac{z f^{\prime}(z)}{f(z)} \frac{f(z)^{\alpha-1} f^{\prime}(z)}{z^{\alpha-1}}>0$$for nonnegative real number $\alpha$, in the open unit disk $U=\{z \in \mathbb{C}:|z|<1\}$ is derived in line with a method of classical analysis devised by Libera and Zlotkiewicz [9].
Oscillation theorems for higher order neutral nonlinear dynamic equations on time scales
Authors: A. Benaissa Cherif  , F. Z. Ladrani  , A. Hammoudi
Published: May 2023

In this paper, we will establish some oscillation criteria for the even-order nonlinear dynamic equation$$\left(a\left(x^{\Delta^{n-2}}\right)^\gamma\right)^{\Delta^2}(t)+f\left(t, x^\alpha(t)\right)=0, \quad t \in\left[t_0, \infty\right)_{\mathbb{T}}$$on a time scales $\mathbb{T}$ with $n$ is an even integer $\geq 3$, where $\gamma$ and $\alpha$ are the ratios of positive odd integer and $a$ is areal valued rd-continuous function defined on $\mathbb{T}$.
Existence results for non-autonomous neutral integro-differential systems with impulsive and nonlocal conditions
Authors: M. Abinaya  , V. Mohana
Published: May 2023

In accordance with semigroup theory, fractional powers of operators, approximation techniques and Banach contraction principle fixed point theorem, this manuscript is primarily involved with the existence results for an impulsive non-autonomous neutral integro-differential systems with nonlocal conditions in Banach space E.
Exact soliton solutions of the generalized combined and the generalized double combined sinh-cosh-Gordon equations
Authors: Nasir Taghizadeh  , Seyedeh Roodabeh Moosavi Noori  , Seyedeh Bahareh Moosavi Noori
Published: May 2023

In this paper, the extended tanh method is used to construct exact solutions of the generalized combined sinh-cosh-Gordon equations and the generalized double combined sinh-cosh-Gordon equations which arises in mathematical physics and has a wide range of scientific applications that range from chemical reactions to water surface gravity waves. The extended tanh method is an efficient method for obtaining exact solutions of nonlinear partial differential equations. This method can be applied to nonintegrable equations as well as to integrable ones.