Mixing Technique Research Articles

Optimal Robust Control of Nonlinear Systems with Unknown Dynamics via NN Learning with Relaxed Excitation.

This paper presents an adaptive learning structure based on neural networks (NNs) to solve the optimal robust control problem for nonlinear continuous-time systems with unknown dynamics and disturbances. First, a system identifier is introduced to approximate the unknown system matrices and disturbances with the help of NNs and parameter estimation techniques. To obtain the optimal solution of the optimal robust control problem, a critic learning control structure is proposed to compute the approximate controller. Unlike existing identifier-critic NNs learning control methods, novel adaptive tuning laws based on Kreisselmeier's regressor extension and mixing technique are designed to estimate the unknown parameters of the two NNs under relaxed persistence of excitation conditions. Furthermore, theoretical analysis is also given to prove the significant relaxation of the proposed convergence conditions. Finally, effectiveness of the proposed learning approach is demonstrated via a simulation study.

Tension evaluation of prestressed strand based on combined features of nonlinear ultrasonic mixing

The estimation of prestressed strand stress levels is of great significance in ensuring the structurally reasonable performance of post-tensioned concrete structures, cable-stayed bridges, and arch bridges. This paper proposes a method to evaluate the remaining tensile stress on the strand through the ultrasonic mixing technique. The relationship between the strand tension and the nonlinear harmonics is established based on the theory of contact acoustic nonlinearity, and the acoustic nonlinear parameters at different tension levels are investigated by finite element analysis and step-loading experiments. The results show that the nonlinear parameters follow a power-law decrease with the increase in the tensile stress. To overcome the shortage of decreasing sensitivity of theoretical nonlinear parameters in monitoring early loosening, support vector regression is introduced to utilize complex high-order nonlinear generations in stress evaluation. With this approach, the accuracy of early-stage stress evaluation based on wave mixing has been remarkably improved.

Succession planning in higher education: A systematic literature review (2012–2022)

This research investigates the dynamic landscape of succession planning (SP) strategies in higher education, with a focus on synthesizing existing literature to guide improvements in presidential succession practices. The intense global competition in higher education has led to imbalances in the quantity and composition of potential successors, hindering institutions’ rapid advancement and affecting their competitiveness on the global stage. The study addresses critical challenges such as attracting, retaining, and nurturing successors in key positions beyond material incentives. Employing a literature analysis methodology, the research comprehensively examines the existing body of literature related to succession planning, offering recommendations to promote stability in leadership, foster continuous talent development, and mitigate talent crises. The study evaluates the current state of succession planning in higher education, identifying issues and their root causes. It provides a summary and analysis of ongoing research efforts related to successor quality, team formation, and cultivation models. Despite advancements through national talent cultivation policies, persistent challenges like talent scarcity, the absence of gender-inclusive succession plans, a lack of originality, and inconsistent staff flow hinder progress. The research attributes these challenges to traditional personnel systems and university administrators. Proactive measures are proposed, including creating awareness of succession planning, advocating for personnel mechanism reform, establishing a comprehensive training system, and developing a scientifically-grounded succession plan. Though the study aims to contribute to leadership development and address pressing issues faced by higher education institutions, with only a limited number utilizing mixed techniques, it restricted the comprehensive inclusion of social context knowledge and evidence regarding the motivations, beliefs, and experiences of individuals in this investigation.

Structural optimization of photoacoustic transducer with PDMS/CSNPs nanocomposite for fatigue crack detection using laser-induced nonlinear surface waves

Laser ultrasonics is a promising non-contact inspection technique but faces challenges of low signal-to-noise and low amplitude under non-destructive thermoelastic regime. In this paper, a laser ultrasonic surface acoustic wave (SAW) modulation method and photoacoustic transducer (PAT) are proposed and combined with nonlinear wave mixing technique to inspect microscale fatigue crack. PATs comprised of candle soot nanoparticles and polydimethylsiloxane are systematically optimized and combined with a line-arrayed laser source to generate desired high-amplitude and pure fundamental SAWs. Two modulated SAWs with frequencies of 2.1 and 2.9 MHz are excited on a fatigued aluminum plate to generate nonlinear mixed components, and the ultrasonic responses over the fatigue crack regions are acquired with a scanning laser Doppler vibrometer. The localization of fatigue crack with microscale is eventually achieved by mapping the nonlinear parameter of the mixed components, which proves it a reliable and non-destructive technique to inspect the fatigue crack.

Characterisation and energy storage performance of 3D printed-photocurable resin/microencapsulated phase change material composite

The 3D fabrication of microencapsulated phase change material (MEPCM) doped resin polymer composites enables the creation of complex shapes and customized designs, opening doors for many applications in fields. This investigation fabricated a range of resin/MEPCM (20 %, 30 %, and 40 % by volume) composites using a mechanical mixing technique. This study investigates how the addition of MEPCM impacts resin matrix composite's mechanical strength, latent heat storage characteristics, and ability to regulate temperature effectively. With a 40 % MEPCM additive ratio, a pure resin porosity value of approximately 0.4 % increased to around 17 %. Thanks to the production of homogeneously dispersed MEPCM added resins with production with stereolithography (SLA), 40 % MEPCM additive enabled characteristic FTIR peaks of both MEPCM and resin to appear and, melting and solidification enthalpy values reached 87.15 j/g and 86.25 j/g, respectively. MEPCM addition enhanced the thermoregulatory properties of resin by absorbing or releasing heat during temperature fluctuations. On hotter days, 8 mm-thick composites create temperature differences exceeding 11 °C, while this difference exceeds 6 °C in the room center case. The produced 3D printed MEPCM/resin composite can be a potential material to effectively regulate the temperature of electronic devices, food packets, building materials, and electronic devices and automotive components.

Review of Mixing Mechanism and Performance of Natural Rubber with Bituminous Materials

Road degradation is a common problem in Malaysia which caused by weather changes, expanding loads as well as the effects of ageing, moisture and temperature results in high maintenance expenses on conventional bitumen pavement. Therefore, it has been recommended on the modification of bitumen as a substitute technique to address this issue and extend the pavement’s lifespan. This study addresses the inadequacy of existing solutions by focusing on the direct mixing approach and the use of pre-treatment using chemical solvent and some additives specifically on epoxidized natural rubber, natural rubber latex and cup lump natural rubber (CLNR). Additionally, this study intends to give a brief summary of how bitumen performance is improved by the inclusion of additives or modifiers by emphasizing the key attributes of modified bitumen after the addition of modifiers. Further information is also provided on the quantity and application method of each addition in order to determine the ideal value for different applications. This study will examine the use of several additives based on past research, such as polyphosphoric acid, Zychotherm, as well as the use of toluene and xylene to maintain the homogeneity of the rubberized bitumen. Studies on the usage of cup lump natural rubber (CLNR) are not common, thus future study should investigate more closely at CLNR and its mixing technique. This research contributes to the field by providing insights into the practical application of modified bitumen for sustainable road construction, especially in regions with a significant rubber industry.

The application of mixed reality technique in oromaxillo-facial reconstruction with the perforator flap for malignant tumor patients.

The integration of quantitative imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) with mixed reality (MR) technology holds promise for enhancing the diagnosis, prognosis, and treatment monitoring of cancer. This study compares the characteristics and effects of MR and color Doppler ultrasound (CDU) in the localization of perforator blood vessels in the lower extremities. Two techniques were used to locate the perforator vessels in 40 cases of maxillofacial defect repair using perforator flaps from the lower extremities. The number of perforator vessels located in the flap area and the actual number of perforator vessels explored during the surgery were recorded. The recognition rate was calculated and the operation time and blood loss were recorded for each case. The recognition rates of MR technology and CDU in perforating vessels of the lower limbs were 93.9% and 97.2%, respectively (p > 0.05). The operation time was 52-74 minutes, 65-88 minutes (p > 0.05). The average bleeding volumes were 24 and 56ml (p < 0.05), respectively. All perforator flaps were alive. One flap had a crisis and recovered after emergency exploratory treatment. Thirty donor sites of the lower extremities were directly sutured, and wounds were closed by abdominal skin grafting in 10 cases. MR technology for successfully identifying perforator vessels can shorten the operation time, reduce the amount of bleeding in the donor site, and reduce trauma to the donor site.

ENVIRONMENTAL IMPACT OF URBANIZATION ON LAND USE COMPATIBILITY AND ENVIRONMENTAL QUALITY IN PORT HARCOURT, RIVERS STATE

This study examined the environmental impact of urbanization on land use compatibility and environmental quality in Port Harcourt Metropolis. The study adopted the multi-method research, integrating both qualitative and quantitative approaches through the convergent mixed method technique, where 399 household heads were selected from 189,317 household heads using the Taro Yamane formula. Questionnaires and checklists were administered to the household heads and ten (10) key informants respectively. Descriptive statistics, critical informant content analysis, and Geographical Information System (GIS) techniques were employed for data presentation and analysis for the study. Multiple Regression Analysis (MRA) was employed to test stated hypothesis for the study. The findings revealed numerous environmental changes resulting from land use/land cover change activities in the area to include deforestation, which accounted for 20.5%, degradation, which represented 19.7%, forest degradation corresponding to 19.7%, generation of waste causing pollution, accounting for 20% and decrease in environmental quality corresponding to 20.1% of the total sampled population of the study. Additionally, the impact of urbanization on environmental quality were revealed as flooding, which accounted for 11% of the sampled respondents as well as air pollution, representing 10.8%. Others ecological disaster (8.7%), waste disposal damping (8.9%), land use incompatibility (7.4%), slum developments and urban heat island (9.6%), land use conflict (8.1%), reduced wetland (8.4%), environmental degradation (7.4%), land use conversion (6.8%), overcrowding of buildings (7.1%) and habitat contamination (7.9%). The study concludes that rapid urbanization has significantly impacted land use compatibility and environmental sustainability in Port Harcourt metropolis. It is therefore recommended amongst others that the government should implement stringent urban development control measures to regulate land use and ensure sustainable urban growth as well as establish policies that limit haphazard expansion and promote planned development.

Cultural Context as the Basis for Developing Reading Game Applications

This research aimed to determine the outcomes of concept analysis and to create and assess the viability of game applications for enhancing reading skills. This is R&amp;D (Research and Development) utilizing the MLDC (Multimedia Development Life Cycle) model. This study was conducted in several elementary schools in Palopo City. The data for the needs analysis was collected from 10 students and two teachers in fourth grade. The number of participants in the effectiveness test phase was 268 students. Observation sheets, documentation, interview guidelines, product validation questionnaires, practicality, and product efficacy were among the data collection instruments. The method of analysis employed is the mixed sequential exploratory technique. The results of the concept analysis determine the type of game application to be developed using contextual media based on local culture and android-based interactivity that promotes independent reading achievement indicator learning. The development of a video game included character introduction features, learning features based on curriculum-based reading, and playing features based on adopting ethnic characters, skin color, clothing, and local genre instrumental music. Through Blackbox testing, the product's feasibility is determined. Practicality test results obtained on average are convenient. The effectiveness test results showed an increase in reading ability by using the developed game product. Keywords: educational game, media development, reading skills, cultural context, elementary school

Boko Haram Terrorism and Development Challenges in the Northeastern Nigeria

The study examines the challenges that hinder development in the Northeast, of Nigeria as a result of the activities of the Boko Haram insurgency. Mixed methods techniques of data collection were adopted to elicit both quantitative and qualitative data using (structured questionnaires) and qualitative (in-depth interviews. A total of 470 respondents were sampled using the Morgan and Krejcie (1970) sample size table. The quantitative data obtained were analysed using both descriptive and inferential statistics while Interpretive Phenomenological Analysis (IPA) was employed for the analysis of the qualitative data. The study found that the Boko Haram violence had adversely affected the development and commercial activities of the areas studied. The destruction of markets, and government buildings, killings and abductions of business owners led to dire developmental challenges. Also, the study found that there was mismanagement of relief materials/assistance for the affected persons, lack of access to food, healthcare services and hygienic facilities in the affected communities and recurrent attacks by the Boko Haram members have hampered any development to take place in the study areas. This study suggests that the reopening of markets, provision of security, pro-poor social investment programs, introduction of surveillance technology, protection of farmers and exploration of natural resources endowed in the areas will rejuvenate the economic and social fortunes of the areas surveyed in this study.

State of art for hybrid mixed finite element formulation in non-linear analysis of structures

Since the late 80’s the Structural Analysis Research Group of the Instituto Superior Técnico (IST) has been involved in the development of non-conventional finite element formulations in order to overcome some of the limitations associated with the use of the CFE method and to develop high performance numerical tools for the analysis of structural engineering problems. Several alternative models for the linear and non-linear structural analysis have been developed using hybrid and mixed models techniques. These works are summarized in this paper, in which their past and future applications of this formulation in non-linear analysis of structures are fully detailed.

Teachers’ Utilization of Bloom’s Cognitive Taxonomy in Examination in Public Secondary Schools in Nandi County, Kenya

Stakeholders are generally concerned in how public secondary schools perform academically in contrast to private schools. The optimal application of Bloom’s Taxonomy should foster increased performance. Thus, the purpose of the study was to ascertain how students’ academic achievement in public secondary schools in Nandi County, Kenya, related to teachers’ application of Bloom’s Cognitive Taxonomy in teaching and examination. The study’s goal was to find out how instructors used Bloom’s Taxonomy when creating internal exams. A pragmatic paradigm was used in the investigation. The foundation of this study was Bloom’s Cognitive Taxonomy. This study used an explanatory sequential design in conjunction with a mixed method research technique. The research population consisted of 2055 teachers from 137 public secondary schools. The sample size was 360 teachers from 30 county schools. 30 county schools were selected using simple random sampling, from which 12 Form 3 teachers teaching 6 selected subjects were identified. Questionnaires and document analysis were used to collect data from examination. Data was analyzed using frequencies, and means. The results showed that 86 % of the teachers utilized Bloom’s Taxonomy when setting exams. The overall percentages for using Bloom’s Cognitive Taxonomy in examination papers were as follows: remembering 29.4%, understanding 28.5%, applying 14.5%, analyzing 9.9%, evaluating 8.7%, and creating 8.8%. The study therefore concluded that, most teachers used Bloom’s Taxonomy when developing internal tests, and recommended that all teachers should utilize Bloom’s Taxonomy and maximize all the levels of it in exams so as to promote an insightful approach to learning and critical thinking experience that will enhance academic performance for the students.

Application of the mixed integer nonlinear programming technique for the economic planning of transmission networks in new manner

Application of the mixed integer nonlinear programming technique for the economic planning of transmission networks in new manner

The optimal placement model for electric vehicle charging stations using bayesian networks

As costs rise and fossil fuels have harmful environ- mental effects more and more people choose electric cars or electric cars this change shows how electric cars are becoming more and more popular in the transportation industry as their fleet grows it becomes clear that more infrastructure is required for charging the first step in the optimization method of this study which aims to identify ideal locations for stations considering user accessibility and investment costs is to identify potential charging locations and places are carefully studied using mixed integer linear programming MLP techniques to identify optimal locations based on historical EV paths the study examines this complex urban environment.

Impacts of Living Conditions on Health Status of Slum Dwellers: A Study of District Gujrat, Punjab, Pakistan

One of the most enduring physical manifestations of the rapid urbanization seen in developing countries has been the development of slum and squatter settlements. Slums and squatter settlements continually grow for a variety of reasons, such as socio-economic, environmental, and living conditions, among many others. Lacking the means of basic facilities, people from these settlements experience the most deplorable living and health conditions. The absence of basic infrastructure, such as unsafe sanitary and hygienic environment, inadequate drinking water, hazardous locations, insecurity and vulnerability, overcrowded and dilapidated habitation, and the nonexistence of waste disposal arrangements creates serious health risks. This study accounts for understanding the living impacts on dwellers by applying mixed research methods and techniques. The primary data was collected from the slums of district Gujrat, Punjab, Pakistan. Collected data was statistically analyzed and also presented through thematic discussion. The results of the study highlighted that most of the slum residents live in pathetic living conditions and suffer from various health issues, especially women and children.

The synergistic effect of greenhouse gas CO2 and silica fume on the properties of 3D printed mortar

To fulfil the requirements of pumpability and buildability, the rheological properties of mortar/concrete for 3D printing should follow much stricter requirements than traditional-cast mortar/concrete. This study proposed to use a secondary CO2 mixing technique coupled with the addition of silica fume (SF) to achieve in-situ rheology control of 3D printed mortar. The influences of CO2 mixing on the properties of the cast mortar and the 3D printed mortar prepared with SF were systematically studied. The pH, conductivity and ion concentration were tested to revel the essential chemical reactions and phase evolutions during CO2 mixing. It was found that the CO2 mixing effectively enhanced the early-age penetration resistance and yield stress of mortar incorporated with SF, and thus significantly improved the buildability of 3D printed mortar, while the maximum printing layer increased higher than 33 layers. Meanwhile, the mechanical properties of the SF-incorporated mortar were improved by this process. It was revealed that during the CO2 mixing process, the injected CO2 rapidly reacted with calcium ions to form CaCO3, which further reacted with C3A to form monocarboaluminate (Mc). The fast precipitation of calcium ions during CO2 mixing accelerated the hydration of C3A and C3S, contributing to the rapid development of strength at early ages and the improved performance of hardened mortar. The addition of SF in mortar greatly amplified the beneficial effect of CO2 mixing, which due to SF as nucleation sites promoted the formation of CaCO3 and Mc during CO2 mixing.

THE ROLE OF ASTRONOMY TOURISM IN PROMOTING EGYPT

This study aims to increase the awareness about the astronomy tourism in Egypt which can be considered as a new and niche branch of tourism, as well as highlighting the potential resources of astronomy tourism in Egypt. The research used mixed methodology technique quantitative and qualitative methods, upon 535 questionnaire forms was distributed along with in-depth interviews with astronomy tourism participants’ then primary data was collected and analyze. The results confirmed that astronomy can be considered as a new type of tourism that have a positive and significant effect on promoting Egypt around the world, in addition results confirm that Egypt is one of the best destinations to go stargazing. This study investigates the importance of taking astronomy tourism into consideration by the ministries and companies and increase awareness about this special interest tourism.

Integration of a web application in Osakidetza Basque Health Service information system to optimize and adapt pharmacy therapeutic of multimorbid patients.

Background: Due to population aging and advances in medical science, people with chronic diseases and polypharmacy are living longer. Challenges are how healthcare systems can cope with the cost burden of chronic disease, sustain a quality independent living for patients; and ensure sustainable healthcare and social care systems. Innovative solutions as well as sustainable integrated workforce solutions are emerging as an alternative to tackle this challenge.&#x0D; Methods: Within Gatekeeper, the Basque Country region is carrying out a “management of people with chronic diseases and polypharmacy"" quasi-experimental study (non-randomized, concurrent and controlled study). The aim is to assess the effectiveness and experience of using a mobile application (My Treatment) to improve adherence of patients with polypharmacy and boost the optimization of pharmacological prescriptions by using a web platform (CheckTheMeds). This study plans to advance as well in the enhancement of Primary Care teamwork, coordination, and communication to acquire new roles to support each other, and offer holistic care to patients.&#x0D; The intervention has been deployed in 11 Integrated Health Organizations of Osakidetza Basque Health Service, Basque Country (Spain). More than 275 healthcare professionals (doctors, nurses, and pharmacy staff) from Primary Care (PC) centers are participating in the intervention. Trained PC healthcare professionals have started the piloting. They have recruited 690 patients who meet the inclusion criteria (65 years of age or older, with 2 or more chronic diseases and 9 or more chronic or on-demand medicines prescribed). The piloting will last until June 2023.&#x0D; Results: 690 patients (intervention and control group) have been included in the study. After signing the informed consent, their health status (Barthel test), prescribed drugs (CheckTheMeds platform), and adherence to treatment (Morisky Green test) are completed at baseline and after a 6-month follow-up. Preliminary data extracted from OAS (Oracle Analytics Services) of Osakidetza reflected that the average age of the recruited patients is 77.9 years, and 58% are male. The average prescription of these patients is 13.10 medicines. 51% of the users are independent (Barthel Test) and 80% of the patients are compliant (Morinsky Green test).&#x0D; The evaluation is being conducted with a mixed methods approach, integrating quantitative and qualitative techniques, by organizing a workshop (November 2022) and a focus group. &#x0D; Discussion and Conclusions: Improved appropriate polypharmacy, together with adherence to prescribed medication, will result in more effective treatments with fewer PRMs and health complications, and therefore, in improved efficiency in the use of healthcare resources. As a consequence, a better use of resources, increasing coordination, and teamwork among primary care healthcare professionals,s and introduction of new roles can improve the efficiency of health systems. Thus, the coordinated action of healthcare professionals, in close collaboration with the patient, is postulated as a common denominator in strategies aimed at improving adherence to treatment and offering new caring skills. This integrated care model is flexible and can be replicated at large scales in different environments.&#x0D;

Exploring the potential of StyleGAN for modeling high-quality and diverse digital wood textures: Towards advancements in the wood industry

Wood texture is pivotal in maximizing the value of trees and timber resources. Consequently, digital modeling and simulation of wood texture have become essential in wood science and industry. Therefore, researching simulation modeling techniques for digital wood texture has significant implications for advancing wood science and industry. This paper introduces a novel approach to modeling and simulating wood texture, focusing on the perspective of deep learning. The proposed method explored the viability of utilizing the StyleGAN model to generate digital wood texture. Fréchet Inception Distance(FID), visual Turing tests, and 1/f fluctuation spectrum analysis were used to evaluate the effectiveness of the digital wood texture models. Additionally, various control techniques were discussed for generating digital wood texture using StyleGAN models. The experimental results strongly indicated that the StyleGAN model exhibits robust capabilities in generating digital wood texture, as evidenced by an FID index of 13. Moreover, the visual Turing tests revealed that professional identification was similar to random guessing, while the fluctuation spectrum analysis demonstrated pixel distribution frequencies similar to those observed in real wood textures. Furthermore, in terms of controlling the simulation of digital wood texture, the StyleGAN model demonstrated remarkable abilities surpassing any previous models based on physical modeling. By fine-tuning truncation parameters and employing network layer mixing techniques, the model could generate the wood texture of various tree species, demonstrating outstanding generalization capabilities.

Solubility Enhancement of Poorly Water-Soluble Drug Ritonavir using Polyvinylpyrrolidone and Chitosan-based Platform Technique

The antiviral medication ritonavir (RTV) belongs to the biopharmaceutics classification system (BCS) class II drug category and is known for its high permeability and poor solubility. Therefore, the prime objective of this research was to increase the rate of dissolution and improve the solubility of RTV using a polymer system. Solid dispersions consisting of binary polymer components i.e., chitosan (CH) and polyvinylpyrrolidone (PVP) were prepared using microwave microwave-assisted physical mixing technique and optimization of solid dispersion was performed with 32 factorial designs. Dispersions were analyzed for their physicochemical characteristics by the use of X-ray diffraction (XRD), differential scanning calorimetry (DSC), and fourier transform infrared spectroscopy (FTIR). The polymeric dispersions prepared were evaluated for the release of RTV throughout 1 h in 0.1N sodium chloride in a USP class II dissolving device. The phase solubility study demonstrated a considerable improvement in the saturation solubility of RTV when CH and PVP K30 were present either individually or in combination. Virtual interaction studies between the drug and polymers revealed physical interactions driven by van der Waals and hydrophobic forces between RTV and excipients. Carbonyl, amine, and hydroxyl groups, among others, were probably present in both RTV and CH, which allowed for these interactions to take place. There was no discernible interaction between the RTV and the polymers included in the FTIR research. The dispersion strategies have improved the dissolving rate, according to the in-vitro drug release investigation. A formulation including a polymeric dispersion of the optimal concentration of PVP and chitosan may efficiently boost the release of RTV, according to the in-vitro release profile.