bluuebunny/crossref_metadata_2025 huggingface dataset:
Echocardiographic findings in patients with acute pulmonary embolism at Sohag University Hospitals
Authors: Eid Mohamed , Boghdady Ahmed Mohamed , Ahmed Mustafa Mohamed , Dahab Lotfy Hamed Abu
Published: February 2022

Background

Acute pulmonary thromboembolism (PTE) is one of the serious medical issues with higher prevalence and mortality rates. As mentioned in several medical reports, most of the chest pain patients, visiting the emergency departments, are usually diagnosed with either acute PTE, acute coronary syndromes, or acute aortic syndromes. The current study aimed to study the risk factors and explore the echocardiographic findings in patients with PTE.

Results

Forty patients with acute pulmonary embolism were enrolled in the study. Echocardiography and computed tomography pulmonary angiography (CTPA) were evaluated for all participants. The echocardiography showed that 29 patients (72.5%) had echocardiographic findings suggestive of acute PTE. Twenty-four patients (60%) had tricuspid regurge. Twenty-one patients (52.5%) had dilated right ventricle (RV). Also, 13 patients (32.5%) had an echocardiographic finding of pulmonary hypertension. Furthermore, ten patients (25%) had McConnell’s sign, and 21 patients (52.5%) had RV systolic dysfunction where only two (5%) showed RV thrombosis. Echocardiographic data of the eight high-risk patients showed that 6 patients (75%) had TR, 8 patients (100%) had dilated RV, 5 patients (62.5%) had pulmonary hypertension, 8 patients (100%) had McConnell’s sign, one patient (12.5%) had RV thrombus, and 8 patients (100%) had RV systolic dysfunction.

Conclusion

The results revealed that thrombus in the main pulmonary trunk was a high-risk factor for patients with acute pulmonary embolism. The current study suggested that echocardiography is an important bedside imaging tool for the diagnosis of PTE. Echocardiography could detect the tricuspid regurge, pulmonary hypertension, McConnell’s sign, RV dilatation, thrombosis, and dysfunction. Furthermore, echocardiography was considered a non-invasive test for rapid diagnosis of PTE and determining the degree of the risk category (high- or low-risk patients) specially with the presence of McConnell’s sign, dilated RV, and RV systolic dysfunction.
A decade of inflammatory bowel disease: a single center experience in Egypt
Authors: Shamkh Mostafa Abd Alfattah , Sakr Mohamed Amin , Abd Alaty Waleed Hamed , Kamel Shimaa Youssef , Eltabbakh Mohamed Mahmoud , Sherief Ahmed Fouad , Rashad Heba , Askar Safaa
Published: February 2022

Background

Inflammatory bowel disease is a chronic inflammatory disorder of the gastrointestinal tract and includes ulcerative colitis and Crohn’s disease. Inflammatory bowel disease has always seemed to be rare in the Middle East and Northern Africa. In this study, we explored the clinical characteristics of inflammatory bowel disease patients in our center.

Methods

This retrospective study was conducted on patients with an established diagnosis of inflammatory bowel disease over 10 years from September 2009 to September 2019 who were referred to our inflammatory bowel disease center. Clinical information was obtained from medical records and patient interviews. We included all patients in whom the diagnosis of ulcerative colitis or Crohn’s disease was confirmed by clinical, laboratory, endoscopic, and histological examination over a 10-year period from 2009 to 2019.

Results

Our study had one hundred and sixty-nine inflammatory bowel disease patients; one hundred and thirty-six ulcerative colitis patients and the remaining thirty-three patients had Crohn’s disease. The main presenting symptom was bloody diarrhea (78 patients) representing 46.2% of the patients in our study. The majority of ulcerative colitis patients (55.9%) had moderate disease (Truelove & Witts score), while the majority of Crohn’s disease patients (66.7%) had moderate to severe disease (Crohn’s Disease Activity Index).

Conclusions

The prevalence of inflammatory bowel disease is still low in Egypt despite the rising curve of newly diagnosed cases.
Fracture Healing in the Setting of Endocrine Diseases, Aging, and Cellular Senescence
Authors: Saul Dominik , Khosla Sundeep
Published: February 2022

More than 2.1 million age-related fractures occur in the United States annually, resulting in an immense socioeconomic burden. Importantly, the age-related deterioration of bone structure is associated with impaired bone healing. Fracture healing is a dynamic process which can be divided into four stages. While the initial hematoma generates an inflammatory environment in which mesenchymal stem cells and macrophages orchestrate the framework for repair, angiogenesis and cartilage formation mark the second healing period. In the central region, endochondral ossification favors soft callus development while next to the fractured bony ends, intramembranous ossification directly forms woven bone. The third stage is characterized by removal and calcification of the endochondral cartilage. Finally, the chronic remodeling phase concludes the healing process.

Impaired fracture healing due to aging is related to detrimental changes at the cellular level. Macrophages, osteocytes, and chondrocytes express markers of senescence, leading to reduced self-renewal and proliferative capacity. A prolonged phase of “inflammaging” results in an extended remodeling phase, characterized by a senescent microenvironment and deteriorating healing capacity. Although there is evidence that in the setting of injury, at least in some tissues, senescent cells may play a beneficial role in facilitating tissue repair, recent data demonstrate that clearing senescent cells enhances fracture repair. In this review, we summarize the physiological as well as pathological processes during fracture healing in endocrine disease and aging in order to establish a broad understanding of the biomechanical as well as molecular mechanisms involved in bone repair.
Wound healing activity of Tropaeolum tuberosum-based topical formulations in mice
Authors: Silva-Correa Carmen R. , Pazo-Medina Greysi I. , Villarreal-La Torre Víctor E. , Calderón-Peña Abhel A. , Aspajo-Villalaz Cinthya L. , Cruzado-Razco José L. , Rosario-Chávarri Jorge Del , González-Siccha Anabel D. , Guerrero-Espino Luz M. , González-Blas María V. , Sagástegui-Guarniz William A. , Gamarra-Sánchez César D. , Hilario-Vargas Julio
Published: February 2022

Background and Aim: Tropaeolum tuberosum Ruiz and Pavón, a tuber native to South America, is characterized by its antioxidant, antimicrobial, and anti-inflammatory properties that contribute to wound healing. This study aimed to evaluate the healing effect of the topical T. tuberosum formulations (gel and cream) on induced wounds in mice. Materials and Methods: Here, an acidic ethanolic extract (1.5 N hydrochloric acid and 96% ethanol at the ratio of 15:85, v/v) was prepared with the tubers of T. tuberosum ecotype black and incorporated into topical cream and gel formulations at 1%. Thirty-twoBalb/c mice were divided into four experimental groups receiving daily topical treatments for 14 days: Group I (control; no treatment), Group II (a commercial ointment of neomycin, polymyxin B, and bacitracin), Group III (1% T. tuberosum gel), and Group IV (1% T. tuberosum cream). The wound closure in the mice was determined during the treatment; then, they were euthanized to obtain skin samples for histopathological analysis. Results: Groups III and IV showed a higher percentage of wound closure from the 6th day of the treatment. From the 8th day, the effect was greater in Group III. The healing effect was confirmed by the histopathological changes. Conclusion: This study concludes that the topical formulations of T. tuberosum demonstrate wound-healing activity in mice, and the most effective treatment is the 1% gel formulation.
Multi-Agent Model of Multi-Nomenclature Small Batch Production
Authors:   Siberian Federal University, Krasnoyarsk, Russian Federation, Russkikh P.A. , Kapulin D.V.
Published: February 2022

Production planning is a key aspect when optimizing production activities. Simulation is one of the most effective methods available for assessing production problems. The principles of adaptive planning consist of making day-to-day operational decisions at the shop floor, predicting equipment availability, assessing performance, and eliminating bottlenecks. Existing research to eliminate bottlenecks has focused on analyzing data from the physical shop, or vice versa, only on the use of simulated data. Convergence between real and simulated data allows, on the one hand, to obtain more information to predict the availability of each workplace, on the other hand, it allows performance assessment for replanning using a simulation model. Aim. Development of optimization tools for production planning using simulation approaches. Materials and methods. This article presents a multi-agent simulation model for each workplace in the workshop, examines the workload of the workshop, and evaluates the productivity of workplaces. Optimization is proposed for optimal utilization of production facilities. As an example illustrating the efficiency and advantage of the proposed model, we took the production process of electronic equipment in the assembly shop. Results. A planning problem and an approach to optimization are formulated. A multi-agent model of multinomenclature small-scale production has been developed. The model provides for the integration of simulation tools with operational planning systems at the data level. Conclusion. The model proposed in the study allows small-scale production to plan the number of jobs and identify bottlenecks in production. The use of a combination of simulation and planning tools ensures enterprise resource management, taking into account dynamic changes in the system.
To the Question of Determining the Barometric Height by a Mechanical Altimeter and Air Signal System
Authors:   Russian Air Force Military Educational and Scientific Center “Air Force Academy  named after Professor N.E. Zhukovsky and Y.A. Gagarin”, Chelyabinsk branch,  Chelyabinsk, Russian Federation, Panferov V.I. , Panferov S.V. , Hayutin А.М. , Trenin N.A. , Yatsuk K.V. ,   South Ural State University, Chelyabinsk, Russian Federation
Published: February 2022

Reliable information on the altitude and speed parameters of the aircraft (AC) is required for safety and increasing the efficiency of flight missions. In this regard, the task of studying the features and improving the characteristics of existing meters for these parameters is quite urgent. Purpose of the study. The features of determining the barometric altitude of an aircraft by a mechanical indicator and an air signal system (SHS) are considered. Materials and methods. The essence of the baro¬metric method for measuring the altitude of the aircraft is analyzed, it is found that to build a clear theory of the method, it is necessary to know the dependence of the temperature of the atmosphere on the altitude. Moreover, it is known that this temperature usually decreases with increasing altitude. However, the rate of decrease unpredictably changes both at different times of the year and day, and at different points and at different heights. Moreover, in some cases, in a certain range of heights, the temperature may not decrease, but, on the contrary, increase. In this regard, there is some problem with the formalization of this dependence. When constructing a theory of the method for mechanical pointers, one proceeds in such a way that the dependence for the International Stan¬dard Atmosphere (ISA) is used, in which temperature and pressure are uniquely related. When developing algorithmic support for SHS, it is considered that the temperature decreases with height as well as in a standard atmosphere, but its actual value at the level of the reference plane can be anything that is not at all related to pressure and altitude in ISA. For this purpose, a temperature control unit is provided in the SHS at the level of the height reference plane. Results. A formula has been obtained that makes it possible to determine the difference between the readings of a mechanical altimeter and SHS. It was found that this difference is a function of pressure and temperature at the level of the plane of the altitude reference plane, as well as the actual pressure at the flight altitude. Numerical studies have been carried out to assess the discrepancy between the readings. It has been established that the relative difference in readings can reach the order of magnitude under ope¬rating conditions, and it practically does not depend on the aircraft altitude and is, in essence, a constant for the indicated initial values of pressure and temperature (at the level of the plane of the altitude reference). Conclusion. The developed algorithms can be used to improve the algorithmic support of the SHS.
Acoustic Sensor for Assessing the State of Production Equipment
Authors:   South Ural State University, Chelyabinsk, Russian Federation, Nekrasov S.G.
Published: February 2022

An important trend in the development of industry is the development of digital models of industrial facilities, the work of which is based on information coming from sensors. This allows you to optimize functionality, predict the technical condition of objects, which is especially important, for example, in the field of metallurgical production, where forced stops are accompanied by huge losses. The sensors themselves are also modeling objects, because they need to adapt to rigid production conditions in which their own shortcomings are manifested, while the correct introduction of corrections for environmental conditions, diagnostics and self-diagnostics, which are impossible without building various types of sensor models, is important. The purpose of the work is to deve¬lop a universal discrete model of an acoustic sensor suitable for receiving and emitting acoustic signals. Methods. The work used methods of classical mechanics and mathematics, vibration theory, generalized functions, distributed systems, and mathematical programming methods were used to provide calculations. Results. The main result is a universal discrete model of a sensor with a working element in the form of a round plate, which by choosing parameters can be transformed into a model of a unidirectional dynamic microphone with a flat membrane or a radiator with a focusing spherical element. It is shown that on the basis of the model it is possible to synthesize narrow-directional radiation diagrams and thereby obtain the necessary spatial selectivity and noise immunity of measurements. Conclusion. Calculations made using the proposed model correspond to the known results of acoustics. Verification of the discrete model using a natural sample showed a high accuracy in determining the resonant frequencies and forms of oscillation of the sensor.
Numerical Method for Processing the Results of Dynamic Measurements
Authors:   South Ural State University, Chelyabinsk, Russian Federation, Yaparov D.D. , Shestakov A.L.
Published: February 2022

The problem of processing data obtained during dynamic measurements is one of the central problems in measuring technology. Purpose of the study. The article is devoted to the study of the stability of the method for solving the problem of processing the results of dynamic measurements with respect to the error in the initial data. Therefore, an urgent task is the development of algorithms for processing the results of dynamic measurements. Materials and methods. This article proposes an algorithm for processing the data obtained during dynamic measurements based on the finite-difference approach. The main prerequisites of the mathematical model of the problem of dynamic measurements associated with the processes of restoration of the input signal in conditions of incomplete and noisy initial data are as follows. Initially, the function of the noisy output signal is known. The restoration of the input signal is carried out using the transfer function of the sensor. The transfer function of the sensor is presented in the form of a differential equation. This equation describes the state of a dynamic system in real time. The proposed computational scheme of the method is based on finite-difference analogs of partial derivatives and the Tikhonov regularization method was used to construct a numerical model of the sensor. The problem of stability of the method for solving high-order differential equations is also one of the central problems of data processing in automatic control systems. Based on the approach of the generalized quasi-optimal choice of the regularization parameter in the Lavrent'ev method, the dependence of the regularization parameter, the parameters of the dynamic measuring system, the noise index and the required level of accuracy was found. Results. The main goal of the computational experiment was to construct a numerical solution to the problem under consideration. Standard test functions were considered as input signals. Test signals simulating various physical processes were used as an input signal. The function of the output signal was found using the proposed numerical method, the found function was noisy with an additive noise of 5 %. Conclusion. The input signal was restored from the noisy signal. The deviation of the reconstructed signal from the initial one in all experiments was no more than 0.05, which indicates the stability of this method with respect to noisy data.
Method of Ensuring that Deviations from Business Process Requirements Are Controlled in the Operation of the Company's Automated Systems
Authors:   Ufa State Aviation Technical University, Ufa, Russian Federation, Antonov V.V. , Shkarov V.N. , Rodionova L.E. , Kulikov G.G. , Kolesnikov V.A. ,   JSC “Ufa Instrument Engineering Production Association”, Ufa, Russian Federation,   JSC “Ufa Scientific and Production Enterprise “Molniya”, Ufa, Russian Federation,   Ufa Law Institute of the Ministry of Internal Affairs of Russia, Ufa, Russian Federation
Published: February 2022

Given the multifaceted nature of the concept of business process, we will limit ourselves to defining business process as a set of interrelated activities or works aimed at creating a certain product or service for customers. From the perspective of the BPM concept, business processes are valuable resources of an enterprise and their management is part of the system of organizational activities, i.e. the organizational system of automated enterprise business process management. Research Objective. Automation, then, is also a business process whose objectives are: the development (acquisition), implementation and operation of software and hardware designed to implement new business process capabilities (which simply were not in the manual loop), optimize and increase the speed of the existing business process, improve working conditions, reduce labor requirements, etc. There is a new direction – computer integration of information. Materials and methods. It is suggested that monitoring deviations from business process requirements be used to organise regular information-technology feedback in the of automated business process management systems of an enterprise. Results. Automation of a business process endows a business process with a new feature – the abi-lity to obtain operational data on all prescribed activities and to integrate all interacting objects of the business process in the implementation of the prescribed set of target functions. In some cases, business process automation is performed to streamline IT-related activities inside the organization. This includes the management of internal resources of the organization – financial, material, human resources, etc. Conclusion. Due to the presence of a sufficiently large number of “legacy systems”, the constantly increasing dynamics of changes in the external environment and the business proces-ses themselves, the task of ensuring the correctness of systems functioning in the absence of the current information model and the current documentation of the automated system seems relevant.
Optimum ECG Signal Filtering Based on Wavelet Transformation
Authors:   South Ural State University, Chelyabinsk, Russian Federation, Saidov B.B. , Telezhkin V.F. ,   Tajik Technical University named after academician M.S. Osimi, Dushanbe, Republic of Tajikistan
Published: February 2022

The development of digital signal processing and microprocessor technology creates conditions for improving methods for diagnosing the functional state of organs. Wavelet analysis is a modern and promising method of information processing. In order to determine the effective optimal filtering of the electrocardiography signal based on the wavelet transform, wavelet filtering was performed using wavelets of different families, the efficiency of using different levels of decomposition, me¬thods for calculating the threshold and types of the threshold function was investigated. Aim. Determination of effective optimal filtering of electrocardiography signal based on wavelet transform. Materials and methods. Cardiograms were taken for analysis. Then they were digitized and entered into a computer for processing. A program was written in the Matlab environment that implements continuous and discrete wavelet transform. Results. As a result of the research, 56 combinations of noise reduction parameters were tested for three noise levels. It was found that the maximum degree of signal purification from noise was obtained using the Coiflets 5 wavelet using a rigid thresholding method, with a heuristic method for calculating the threshold value. Wavelet Simlet 8 has lower correlation coefficient values than Coiflets 5, at 35 dB the best result is 97%, the noise level is 40 dB the best result is 98.7%, the noise level is 45 dB the best result is 99.3%, which is generally negligible differs from the correlation coefficients of the wavelet Coiflets 5. Conclusion. As a result of the study, the first and the present work, the following conclusions were made: the optimal level of the wavelet decomposition of the ECG signal N = 2; the maximum degree of signal cleaning from noise was obtained using the Coiflets 5 wavelet using a rigid thresholding method, with a heuristic method for calculating the threshold value; Simlet 8 wavelet using a soft thresholding method with a minimax thresholding method also shows noteworthy results, slightly inferior to Coiflets 5 wavelet results.
A Local Wisdom in East Flores and the Shift: The Transition of the Lamaholot Religion to the Catholic Religion
Authors: Kebingin Benedikta Yosefina , Martasudjita Emanuel
Published: February 2022

This study aims, firstly, to determine the factors that led to the conversion of the Lamaholot religion to the Larantuka Catholic religion. Second, to find out the social impact upon  religious conversion of Lamaholot to Catholicism on the daily life of the people in Larantuka. And how this will gave us the basic understanding upon the history of the transition and how Catholic religion still thriving till nowadays. This study uses a qualitative method with an ethnographic approach. The research locations are spread across three sub-districts, namely Larantuka, Lewolema, and Ilemandiri. Sources of data obtained through document analysis, interviews focused on key informants, direct involvement, observation and introspection. The research results were analyzed using domain, taxonomy, and componential techniques. The theology paradigm used on this writing is the Theology of the Incarnation. How God humanizes and enters the local culture, illuminates it with divine light so that the adherents of the culture can see into the depths of themselves the truth that comes from that light.
School Information Management System (SIMS/EMIS) in Lebanon through the Lens of K-12 Public School Leaders: A Burden or an Opportunity?
Authors: Shal Tarek
Published: February 2022

The purpose of this paper was to investigate the importance of the Education Management Information System (EMIS) “known as School Information Management System (SIMS)” for the Lebanese public k-12 schools.  It is a quantitative study that surveyed the whole population of the K-12 public schools in Lebanon (N=1237[1]). It aimed to determine if SIMS was considered an efficient tool for school principals to improve the quality of learning in their schools.  It addressed the multiple technical, human, financial and managerial aspects of SIMS, the different challenges that Lebanese school principals confront while using SIMS. Additionally, it aimed to investigate the improvements school principals suggested and the alternatives they proposed.  The study provides recommendations for the Lebanese Ministry of Education and Higher Education on how to improve this application to develop the education sector in Lebanon.
Expanding Lattice Ordered Abelian Groups to Riesz Spaces
Authors: Di Nola Antonio , Lenzi Giacomo , Vitale Gaetano
Published: February 2022

First we give a necessary and sufficient condition for an abelian lattice ordered group to admit an expansion to a Riesz space (or vector lattice). Then we construct a totally ordered abelian group with two non-isomorphic Riesz space structures, thus improving a previous paper where the example was a non-totally ordered lattice ordered abelian group. This answers a question raised by Conrad in 1975. We give also a partial solution to another problem considered in the same paper. Finally, we apply our results to MV-algebras and Riesz MV-algebras.
Ordinary Generating Functions of Binary Products of Third-Order Recurrence Relations and 2-Orthogonal Polynomials
Authors: Merzouk Hind , Boussayoud Ali , Abderrezzak Abdelhamid
Published: February 2022

In this paper, we introduce the new generating functions for the product of some numbers and 2-orthogonal polynomials by making use of the symmetrizing endomorphism operators π

e
2
e
3

π

e
1
e
2
to the series

∑

n
=
0

+
∞

S
n

(

A
3

)

e
1
n

z
n

.
Joint Approximation by Dirichlet L-Functions
Authors: Laurinčikas Antanas , Šiaučiūnas Darius
Published: February 2022

In the paper, collections of analytic functions are simultaneously approximated by collections of shifts of Dirichlet L-functions (L(s + iγ
1(τ), χ
1),…, L(s + iγ

r
(τ), χr
)), with arbitrary Dirichlet characters χ
1,…, χr
. The differentiable functions γ
1(τ), …, γ

r
(τ) and their derivatives satisfy certain growth conditions. The obtained results extend those of [PAŃKOWSKI, Ł.: Joint universality for dependent L-functions, Ramanujan J. 45 (2018), 181–195].
Generalizations of Hardy Type Inequalities by Taylor’s Formula
Authors: Krulić Himmelreich Kristina
Published: February 2022

In this paper, we use Taylor’s formula to prove new Hardy-type inequalities involving convex functions. We give new results that involve the Hardy–Hilbert inequality, Pólya–Knopp inequality and bounds for the identity related to the Hardy-type functional. At the end, mean value theorems of Cauchy type are given.
Oscillation of Second Order Delay Differential Equations with Nonlinear Nonpositive Neutral Term
Authors: Baculíková Blanka , Sudha B. , Thangavelu K. , Thandapani E.
Published: February 2022

This paper deals with oscillation of a second order delay differential equations with a nonlinear nonpositive neutral term. Some new oscillation criteria and three examples are presented which improve and generalize the results reported in the literature.
Existence and Asymptotic Periodicity of Solutions for Neutral Integro-Differential Evolution Equations with Infinite Delay
Authors: Zhu Jianbo , Fu Xianlong
Published: February 2022

In this work, making use of the theory of resolvent operators and Banach fixed point theorem, we first discuss the existence and regularity of mild solutions for neutral partial functional integro-differential equations with infinite delay. We assume that the linear part of the considered equation generates a resolvent operator and the nonlinear function satisfies Lipschitz conditions. Then we investigate the asymptotic periodicity of mild solutions under asymptotic periodic assumption on the nonlinear function. The obtained results extend somewhat the related conclusions in literature. In the end, an example is presented to illustrate the obtained results.
A Korovkin Type Approximation Theorem For Balázs Type Bleimann, Butzer and Hahn Operators via Power Series Statistical Convergence
Authors: Söylemez Dilek
Published: February 2022

In this paper, we obtain a Korovkin type approximation theorem for power series statistical convergence of functions belonging to the class produced by multivariable modulus of continuity function. As an application of this theorem, we construct a non-tensor product Balázs type BBH operator which does not converge in ordinary sense. Moreover, we study promised approximation properties of this operator and compute the rate of convergence. Finally, we prove that our new approximation result works but its classical case fails.
Hyperbolic Geometry For Non-Differential Topologists
Authors: Niemiec Piotr , Pikul Piotr
Published: February 2022

A soft presentation of hyperbolic spaces (as metric spaces), free of differential apparatus, is offered. Fifth Euclid’s postulate in such spaces is overthrown and, among other things, it is proved that spheres (equipped with great-circle distances) and hyperbolic and Euclidean spaces are the only locally compact geodesic (i.e., convex) metric spaces that are three-point homogeneous.
Set Star-Menger and Set Strongly Star-Menger Spaces
Authors: Kočinac Ljubiša D. R. , Konca Şukran , Singh Sumit
Published: February 2022

Motivated by the Arhangel’skii “s-Lindelöf cardinal function” definition, Kočinac and Konca defined and studied set covering properties and set star covering properties. In this paper, we present results on the star covering properties called set star-Menger and set strongly star-Menger. We investigate the relationship among set star-Menger, set strongly star-Menger and other related properties and study the topological properties of set star-Menger and set strongly star-Menger properties.
The U Family of Distributions: Properties and Applications
Authors: Jamal Farrukh , Chesneau Christophe , Saboor Abdus , Aslam Muhammad , Tahir Muhammad H. , Mashwani Wali Khan
Published: February 2022

In this article, we develop a new general family of distributions aimed at unifying some well-established lifetime distributions and offering new work perspectives. A special family member based on the so-called modified Weibull distribution is highlighted and studied. It differs from the competition with a very flexible hazard rate function exhibiting increasing, decreasing, constant, upside-down bathtub and bathtub shapes. This panel of shapes remains rare and particularly desirable for modeling purposes. We provide the main mathematical properties of the special distribution, such as a tractable infinite series expansion of the probability density function, moments of several kinds (raw, incomplete, probability weighted…) with discussions on the skewness and kurtosis. The stochastic ordering structure and stress-strength parameter are also considered, as well as the basics of the order statistics. Then, an emphasis is put on the inferential features of the related model. In particular, the estimation of the model parameters is employed by the maximum likelihood method, with a simulation study to confirm the suitability of the approach. Three practical data sets are then analyzed. It is observed that the proposed model gives better fits than other well-known lifetime models derived from the Weibull model.
A New Method for Generalizing Burr and Related Distributions
Authors: Chakraborty Tanujit , Das Suchismita , Chattopadhyay Swarup
Published: February 2022

A new method has been proposed to generalize Burr-XII distribution, also called Burr distribution, by adding an extra parameter to an existing Burr distribution for more flexibility. In this method, the exponent of the Burr distribution is modeled using a nonlinear function of the data and one additional parameter. The models of this newly introduced generalized Burr family can significantly increase the flexibility of the former Burr distribution with respect to the density and hazard rate shapes. Families expanded using the method proposed here is heavy-tailed and belongs to the maximum domain of attractions of the Frechet distribution. The method is further applied to yield three-parameter classical Pareto and generalized exponentiated distributions which shows the broader application of the proposed idea of generalization. A relevant model of the new generalized Burr family has been considered in detail, with particular emphasis on the hazard functions, stochastic orders, estimation procedures, and testing methods are derived. Finally, as empirical evidence, the new distribution is applied to the analysis of large-scale heavy-tailed network data and compared with other commonly used distributions available for fitting degree distributions of networks. Experimental results suggest that the proposed Burr distribution with nonlinear exponent better fits the large-scale heavy-tailed networks better than the popularly used Marhsall-Olkin generalization of Burr and exponentiated Burr distributions.
Integrating Lean and Sustainable Manufacturing Principles for Sustainable Total Productive Maintenance (Sus-TPM)
Authors: Crosby Brett , Badurdeen Fazleena
Published: February 2022

Total productive maintenance (TPM) is a systematic method to ensure equipment can function at the required performance to meet customer demand. The benefits of TPM are well known in lean manufacturing environments, and the technique is widely used to ensure no waste is created by defective equipment. Lean manufacturing principles and practices provide a solid basis to build upon to create more sustainable products, processes, and systems. TPM practices, therefore, can serve as a useful tool for more sustainable maintenance practices, leading to more sustainable manufacturing when additional criteria are incorporated into the existing foundation of the practice. This paper introduces a framework to integrate sustainability criteria and develop Sustainable TPM (Sus-TPM) as a complement to TPM practices. The approach to visually present the temporal sustainability performance variation of equipment by developing impact assessment trees using the Sus-TPM technique is presented. The application of the approach to an example is provided to demonstrate its benefits. Potential future expansions are also discussed to highlight how the Sus-TPM methodology could become an important tool for more sustainable manufacturing.
Performance Analysis of Electro-chemical Machining of Ti-48Al-2Nb-2Cr Produced by Electron Beam Melting
Authors: Galati Manuela , Defanti Silvio , Denti Lucia
Published: February 2022

Ti-48Al-2Nb-2Cr is a challenging and difficult-to-cut titanium aluminide (TiAl) alloy with several manufacturing issues because of the high sensitivity to crack formation and oxygen picking up. Electron beam powder bed fusion (EB-PBF) made feasible TiAl near net shape components, but the surfaces are particularly rough and present complex surface topographies. In this present investigation, experimental analysis and optimization are proposed for electro-chemical machining (ECM) on as-built Ti-48Al-2Nb-2Cr surfaces manufactured using EB-PBF. Experimental runs are performed under pulsed machining conditions and varying specific process metrics to understand the machining effects on the process efficiency and removal phenomena. In particular, the morphology and isotropy of the surface are studied before and after the machining by scanning electron and confocal microscopies. The results establish the optimal machining conditions and a range for the active machining time that produce, compared to the as-built surface, an extremely smooth and isotropy surface without any detrimental effect on the surface integrity and microstructure.
The Roles of Long Non-coding RNAs in Osteogenic Differentiation and Bone Diseases
Authors: Qin Sen , Liu Da , Zhou Zimo , Chen Senxiang
Published: February 2022

Bone marrow mesenchymal stem cells play an important role in osteogenic differentiation, and they complete this important biological process through the coordination of various transcription factors and signal pathways. In recent years, studies have clearly confirmed that long non-coding RNAs (lncRNAs) are involved in osteogenic differentiation, which plays an important biological role in the occurrence and development of osteogenesis-related bone disease. This article reviews the roles and related mechanisms of lncRNAs in osteogenic differentiation, as well as their potential effects on a variety of bone diseases. This understanding may help researchers identify potential therapeutic targets and biological markers in the future.
impact of the pandemic on communication between local government and citizens in a small village in Tuscany
Authors: Farinosi Manuela , Cirulli Adriano , Fortunati Leopoldina
Published: February 2022

The COVID-19 pandemic has fostered the increasing use of digitally-mediated communication, which has substituted a large part of the face-to-face encounters, work, political, social, and leisure activities, made impossible during the long period of lockdown. What did this entail in small villages, in respect to both citizens and local government, where face-to-face communication has been more resistant to digital mediation? This study aimed to explore the changes seen in institutional communication, and more generally, in the everyday life of citizens and their relationship with local administrators during the first lockdown in Italy. The context explored was the small-scale local community of Peccioli (Tuscany), a village where face-to face communication usually played a pivotal role in the interaction between local government and citizens. This small village represents a good point of observation to understand whether, in contexts such as this, there has been a change in the balance between different modes of communication similar to that seen in more urban environments.
More specifically, the paper presents the main findings emerging from a study exploring on the one hand, the attitudes and opinions of local administrators regarding institutional communication, and, on the other, the evaluations by citizens of the initiatives and the communication by local government and an analysis of their information behaviors. In the first case, a qualitative approach was used, based on 10 semi-structured interviews with local administrators; in the second case, a quantitative approach was adopted based on a survey conducted with a representative sample of Peccioli’s citizens. The main finding of the study revealed the crucial role of word of mouth, thus indicating that, contrary to what is generally believed, not all communication has become automatically digital during COVID-19.
Parameter optimization study based on co-briquetting tests of corn straw and potato residue
Authors: Guo Wenbin , Wang Zhipeng , Hu Fan , Hou Zhibo , De Xuehong
Published: February 2022

Corn straw and potato residue are common agricultural biomass. Although they have a wide range of applications, the disadvantages of low bulk density and high storage and transportation cost hinder their utilization. The densification of these biomass into briquettes facilitates their storage, transportation, and reuse. The rheological properties of corn straw and potato residue during co-briquetting were investigated in creep tests. The Four-element Burgers Model accurately and intuitively fit the creep curves of the mixed materials, with fitting coefficients above 0.99. The experiment used the relaxation ratio as an indicator, and the influence of compression speed, dwell time, feeding amount, loading force, mass ratio, and temperature were obtained. The response surface analysis indicated that all factors except compression speed had an effect on the relaxation ratio. The results suggested that compressing corn straw and potato residue in a feeding amount of 28 g with a mass ratio of 1:5 at 101 °C under 35 KN loading force and 918 s dwell time produces cost-effective agricultural biomass briquettes. This study provides a reference for improving the co-briquetting process of corn straw and potato residue.
Viscoelastic and dynamic characteristics of wood-melamine-urea-formaldehyde composites prepared by in situ polymerization
Authors: Lang Qian , Zhang Chao , Liu Chuanhao , Zhang Huimin , Zhang Shengming , Li Longhai , Chen Haitao
Published: February 2022

The viscoelastic behavior and the dynamic mechanical properties were studied for wood-melamine-urea-formaldehyde composites prepared from fast-growing poplars using in situ polymerization. The changes in stress relaxation (SR), storage modulus (E′), and damping parameter (tan δ) were considered. The relationship between the dynamic mechanical properties and the modifier concentration was also studied. The SR value decreased as the modifier content increased in all the samples examined. The urea content had a greater impact than the melamine-urea-formaldehyde mixture content on the SR value of the wood samples. A similar trend was observed for E′. The modified wood samples exhibited a higher tan δ. The results confirmed that a better interfacial interaction between melamine-urea-formaldehyde and wood fiber contributed to the improvement of mechanical properties in the fast-growing poplar wood.
Determination of mechano-sorptive coefficients in Eucalyptus nitens wood under isothermal conditions
Authors: Salinas Carlos , Chávez Cristian , Cárdenas Francisco , Torres José , Ananias Rubén
Published: February 2022

New experimental data is presented for the mechano-sorptive coefficient of Eucalyptus nitens wood analyzed in the longitudinal direction through the principle of total deformation superposition. The procedure was based on the determination of the partial strain components: elastic strain, free shrinkage strain, and mechano-sorptive strain. The methodology included the design of cantilever flexion tests of a wooden beam in an air-conditioned environment with variable relative humidity. These conditions made it possible to estimate each of the deformation components separately and then to determine the mechano-sorptive coefficient using the rheological stress-strain model. Deformations and displacements were evaluated with extensometers and displacement sensors, respectively, in conditions of 0 to 30% of the breaking load applied perpendicularly to beams oriented in the longitudinal direction. The cross-section was positioned according to the relation between the action line of the load applied and the growth rings orientation. The variation of moisture content was considered, decreasing from 22 to 12%. The results exposed a direct proportionality between the intensity of the applied load and the mechano-sorptive strains. The values determined for mechano-sorptive coefficients were 0.1224 and 0.1746 GPa-1 for loads applied to radial and tangential directions, respectively.
Efficient lignin depolymerization with Ru- and W- modified bi-functional solid acid catalyst
Authors: An Shengxin , Wang Jindong , Zhou Zean , Zhang Baikai , Xue Fengyang , Wang Huizhen , Li Wenzhi
Published: February 2022

A novel Ru-modified composite catalyst, Ru-W/Sn-AlOx, was prepared, and the effects of the catalyst on lignin depolymerization were investigated in this study. The catalyst converted approximately 95% lignin into liquid product at 300 °C in 12 h and 2/3 of the liquid product could be soluble in petroleum ether. The petroleum ether (PE) soluble product was mainly composed of monomers, dimers and some trimmers. This indeed indicated that the catalyst could effectively depolymerize lignin into small-molecule products. 7.22% of monomers was obtained at 310 C for 12 h. Meanwhile, the catalyst effectively reduced the char formation to 2%. After the catalytic depolymerization, the higher heating value (HHV) of the liquid product increased from 25.7 to 32.4 MJ/kg. The product could be utilized as fuel additive or converted to biofuels. This catalysis system showed great potential in the conversion of lignin into biofuels.
Anatomical and physical properties of three lesser-known timber species from Malaysia
Authors: Siam Nordahlia Abdullah , Lipeh Shahlinney , Uyup Mohd Khairun Anwar , Juhari Muhammad Amirul Aiman Ahmad , Talip Noraini , Amri Che Nurul Aini Che , Abdullah Nor Azahana
Published: February 2022

The purpose of this study was to determine the anatomical and physical properties of three lesser-known Malaysian timber species, i.e., mahang (Macaranga hosei), medang (Litsea costalis), and terap (Artocarpus scortechinii). Correlation factors that influenced the density and shrinkage were also discussed. From the results obtained, terap wood had the longest fibre (1421 µm), followed by medang (1309 µm), and mahang (1161 µm). Terap, medang, and mahang were categorized as having very thin fibres. The density of terap, medang, and mahang had average values of 504 kg/m3, 485 kg/m3, and 474 kg/m3, respectively. In addition, terap wood also showed the highest tangential shrinkage (3.8%), followed by mahang (2.2%) and medang (1.5%) wood. This present study showed that the density was significantly influenced by the fibre length, fibre wall thickness, vessel diameter, and number of vessels. In addition, the shrinkage was highly correlated with the density. Based on the conducted research, mahang, medang, and terap show potential as alternative raw material to fulfill demand in wood-based industries.
Modulus of rupture prediction in Pinus sylvestris with multivariate models constructed with resonance, ultrasound, and wood heterogeneity variables
Authors: Fernández-Serrano Álvaro , Villasante Antonio
Published: February 2022

Multivariate models with multiple linear regression (MLR), artificial neural network (ANN), and k-nearest neighbors (KNN) were developed to predict the modulus of rupture of Pinus sylvestris structural timber. The aim of this study was to develop and compare these models obtained from resonance and ultrasound tests, static modulus of elasticity tests, and different measured wood feature. Resonance tests were performed in the three vibration modes (edgewise, flatwise, and longitudinal) to obtain the fundamental resonant frequencies. To compare the goodness-of-fit of the different models, the 10-fold cross-validation method was used, which proved to be an adequate strategy to avoid overfitting. The variable with the best predictive capacity of the modulus of rupture was knottiness. The error was notably lower in the multivariate than the univariate models. The ANN and KNN algorithms showed no improvement over the MLR. The most suitable MLR for prediction of the modulus of rupture was the model with four variables: knottiness, edgewise dynamic modulus of elasticity, velocity of ultrasounds, and longitudinal resonant frequency.
Fabrication of eco-friendly time indicator using cellulose-based materials
Authors: Jo Hae Min , Lee Yeon Hui , Lee Ji Young
Published: February 2022

An eco-friendly time indicator (TI) was developed using cellulose-based materials. The TI comprises a dye, copy paper, nanofibrillated cellulose (NFC) film, and filter papers coated with NFC slurry and/or paraffin-free biowax. A suitable dye and its conditions were determined by observing the dye solutions and the migration pattern at the different concentrations. Commercial filter papers were prepared, and the dye migration rate, depending on physical properties, was evaluated. NFC was coated to control the dye migration rate of filter paper. In addition, biowax was used to impart hydrophobicity to filter papers used for supporting NFC films, storing the dye, and allowing the migration of dye. Finally, a TI was fabricated using those components. Methylene blue was selected as a dye for the TI due to its deep color and high solubility. The results showed that the key property of filter paper affecting the dye migration rate was the pore size. The migration rate could be reduced when NFC was coated on both sides of the filter paper. Since biowax modified the hydrophobicity of filter paper surface, it was used to make the NFC film-supporting paper, location for dye storage, and bottom-layer. In conclusion, a multilayered TI could be assembled using cellulose-based materials.