Combination Of Techniques Research Articles

Urinary continence following extraperitoneal radical prostatectomy: impact of surgical technique and pelvic fascial spaces reconstruction

Introduction. Urinary incontinence is a common complication of radical prostatectomy. The development of surgical techniques when performing radical prostatectomy that improve the function of urinary continence after surgery is actual.Objective. To compare urinary continence functions in long-term follow-up after open and laparoscopic radical prostatectomy when only posterior or combined (anterior + posterior) reconstruction of the pelvic fascial spaces is performed.Materials & methods. The study included 130 patients aged 63.0 [59.0; 68.0] years with local prostate cancer (сT1a-2сN0-xM0; 1 – 4 ISUP groups), subjected to non-nerve-sparing retropubic radical prostatectomy with posterior reconstruction and non-nerve-sparing extraperitoneal laparoscopic radical prostatectomy with isolated posterior or combined (anterior + posterior) fascial reconstruction of the pelvic fascial spaces. Postoperative continence function was studied at 1, 3, 6, and 12 months following surgery using a standard pad test.Results. The incidence of urinary continence was higher at all follow-up periods during laparoscopic surgery. From the 6-months follow-up, these patients did not have severe urinary incontinence. At the same time, the rate of growth of some patients who began to retain urine did not depend on the method of reconstruction of the pelvic fascial spaces. The use of combined reconstruction of the pelvic fascial spaces at 12-months follow-up showed an advantage in urinary continence over performing only posterior reconstruction. Such patients achieved urinary continence in 90% of cases compared to 80.0% of cases. At the same time, the restoration of urinary continence at all periods of observation had a relatively uniform linear rate of increase in the indicator.Conclusion. Reconstruction of the pelvic fascial spaces during open and laparoscopic radical prostatectomy allows one to achieve satisfactory continuation in the postoperative period. However, higher efficiency is achieved when using a combined reconstruction technique.

Aerodynamic and Structural Design Procedures Supported by Fabrication and Flight Testing of a Small Unmanned Helicopter

In this work, typical design, production, and testing procedures for a small unmanned helicopter are explained and performed. In doing so, preliminary sizing of the helicopter and three main disciplines are conducted: aerodynamic analytical and numerical simulations, power calculations, and structure analysis assessment. First, a thorough survey is implemented to obtain the trends for the maximum take-off weight versus some design constraints such as rotor diameter, motor power, payload, and empty weight. Performance calculation results are obtained to figure out all aspects that correspond to the specified mission. The designed rotor geometry along with the aerodynamic characteristics and flight performance variables is then validated using the blade element theory and numerical simulations. Second, based on the power curves obtained for different flight regimes, an electric brushless motor is selected. The numerical simulations (Computational Fluid Dynamics) analysis is used to enhance the selection which implies that the motor power should be greater than 5.4 kW to overcome the drag forces. The motor power selection corresponds to a maximum rotor pitch angle of 15∘ and a maximum rotor speed of 1450 RPM. Then, the aerodynamic loads are used as an input for the structural analysis using one-way coupling of fluid–structure interaction (FSI) and consequently designing the internal structure of the blade. Eventually, the internal structure manufactured using carbon fiber-reinforced polymer (CFRP) by applying a combined technique between wet layup and compression molding. The blade is statically tested compared with numerical finite element model results. The fuselage structure along with hub and tail units is manufactured and assembled with the existing on-shelf components to examine the helicopter lift capability with different payloads up to 9 kg. The results show that the detailed design process is significant for manufacturing such blades and the helicopter is capable of lifting off the ground with various payloads depending on the rotor pitch angles (8∘, 12∘, and 15∘) at a constant rotor speed of 1450 RPM.

Preservation of the native urethral plate and corpus spongiosum combined with buccal mucosa graft plus Orandi's penile skin flap as an alternative to staged urethroplasty for narrow penile strictures.

In narrow anterior urethral strictures, the combined buccal mucosa graft (BMG) with pedicled penile skin flap (PSF) represents a well-known effective alternative to staged urethroplasty. We hypothesized that if the native urethral plate and adjacent corpus spongiosum were preserved, a narrower flap would be needed, and reinforced ventral stability could be achieved without compromising the surgical outcome. Twelve patients with narrow penile urethral strictures underwent single-stage augmentation urethroplasty using a combined technique. A BMG was quilted to the corpora cavernosa in a dorsal onlay approach, and a longitudinal ventral PSF was transposed ventrally and sutured to the scarred native urethral mucosa on one side and to the BMG on the other side to form a neourethra of triangular form. The preserved corpus spongiosum was wrapped and fixed around the flap ventrally. The median age was 47 years (IQR 35-59), and the median stricture length was 5 cm (IQR 3, 8-7). The median surgical time was 205 min (IQR 172-236). The overall success rate (SR) was 91.7% without sacculation or diverticula formation after a median follow-up period of 38 months (IQR 33-40). Three transient fistulas healed through prolonged urinary diversion. Five patients (41.7%) reported postvoid dribbling following urethroplasty. Preservation of the native urethral plate is a valuable adjunct to the combination of graft and flap for single-stage augmentation urethroplasty for narrow urethral strictures, with satisfactory mid-term success and an acceptable complication rate.

A combined technique for power transformer fault diagnosis based on k‐means clustering and support vector machine

AbstractThis contribution presents a two‐step hybrid diagnostic approach, combining k‐means clustering for subset formation, followed by subset analysis conducted by human experts. As the feature input vector has a significant influence on the performance of unsupervised machine learning algorithms, seven feature input vectors derived from traditional methods, including Duval pentagon method, Rogers ratio method, three ratios technique, Denkyoken method, ensemble gas characteristics method, Duval triangle method, and Gouda triangle method were explored for the subset formation stage. The seven proposed individual methods, corresponding to the seven feature input vectors, were implemented using a dataset of 595 DGA samples and tested on an additional 254 DGA samples. Furthermore, a combined technique based on a support vector machine was introduced, utilising the diagnostic results of the individual methods as input features. From training and testing, with diagnostic outcomes of 91.09% and 90.94%, the combined technique demonstrated the highest overall diagnostic accuracies. Using the IEC TC10 database, the diagnosis accuracies of the proposed diagnostic methods were compared to existing methods of literature. From the results obtained, the combined technique outperformed the proposed individual methods and existing methods used for comparison.

Endoscopic treatment of gastric varices: when and how?

Abstract Bleeding from gastric varices is less common than from esophageal varices, but when it occurs, it does so more rapidly and profusely, with higher rates of rebleeding and mortality. Therefore, understanding their complex pathophysiology and vascularization is essential, posing a significant endoscopic and therapeutic challenge. To classify them, the Sarin classification must be used, with fundic varices posing the greatest risk of bleeding and being the focus of this controversy. When there is active bleeding from fundic varices, treatment must be applied; however, high-quality data to choose the optimal strategy remain limited. Nonetheless, clinical practice guidelines strongly recommend treatment with cyanoacrylate via conventional gastroscopy, as it is an effective, relatively easy, and safe technique to apply in an emergency. Special precautions must be taken when applying cyanoacrylate due to its complications, the most feared being systemic embolisms. To minimize or even eliminate complications, the combined technique (cyanoacrylate + coils) guided by endoscopic ultrasound was developed. This treatment modality could be considered the most effective and safe technique, and although it is not yet the preferred choice for acute bleeding, it plays a fundamental role in secondary prophylaxis. It is endorsed by the ESGE guideline and has been included in the research agenda for the upcoming Baveno consensus.

Placental multimodal MRI prior to spontaneous preterm birth

To utilise combined diffusion-relaxation MRI techniques to interrogate antenatal changes in the placenta prior to extreme preterm birth among both women with PPROM and membranes intact, and compare this to a control group who subsequently delivered at term. Observational study. Tertiary Obstetric Unit, London, UK. Cases: pregnant women who subsequently spontaneously delivered a singleton pregnancy prior to 32 weeks' gestation without any other obstetric complications. pregnant women who delivered an uncomplicated pregnancy at term. All women consented to an MRI examination. A combined diffusion-relaxation MRI of the placenta was undertaken and analysed using fractional anisotropy, a combined T2*-apparent diffusion coefficient model and a combined T2*-intravoxel incoherent motion model, in order to provide a detailed placental phenotype associated with preterm birth. Subgroup analyses based on whether women in the case group had PPROM or intact membranes at time of scan, and on latency to delivery were performed. Fractional anisotropy, apparent diffusion coefficients and T2* placental values, from two models including a combined T2*-IVIM model separating fast- and slow-flowing (perfusing and diffusing) compartments. This study included 23 women who delivered preterm and 52 women who delivered at term. Placental T2* was lower in the T2*-apparent diffusion coefficient model (p < 0.001) and in the fast- and slow-flowing compartments (p = 0.001 and p < 0.001) of the T2*-IVIM model. This reached a higher level of significance in the preterm prelabour rupture of the membranes group than in the membranes intact group. There was a reduced perfusion fraction among the cases with impending delivery. Placental diffusion-relaxation reveals significant changes in the placenta prior to preterm birth with greater effect noted in cases of preterm prelabour rupture of the membranes. Application of this technique may allow clinically valuable interrogation of histopathological changes before preterm birth. In turn, this could facilitate more accurate antenatal prediction of preterm chorioamnionitis and so aid decisions around the safest time of delivery. Furthermore, this technique provides a research tool to improve understanding of the pathological mechanisms associated with preterm birth invivo.

Fixation techniques for periprosthetic femur fractures around total knee arthroplasty: a systematic review

There is no consensus regarding the treatment algorithm for the fixation of periprosthetic femur fractures (PFFs) around a total knee arthroplasty (TKA). Established methods of fracture fixation include locking plate (LP) or retrograde intramedullary nail (RIN) techniques. Newer fixation methods include the dual plate (DP) and the nail-plate combination (NPC) techniques. The purpose of this study is to review the literature on the outcomes of PFF fixation following TKAs over the past two decades. A systematic review was undertaken in the MEDLINE, Embase, and Cochrane databases in accordance with the PRISMA standards. Selection criteria included: patient cohort &gt; 5 cases and minimum follow-up of 12 mo. Risk of bias was assessed with the Joanna Briggs Institute Critical Appraisal Checklists for Cohort Studies and Case Series. Combined data analysis was performed with linear models and linear mixed effect models to compare the post-operative outcomes of the LP, RIN, and DP techniques. Our search identified 1086 studies and 31 were selected for final analysis. The number of the studies for the LP, RIN, DP, and NPC techniques were 23, 15, 4, and 1, respectively. There were no differences in the time to union, Knee Society Knee Score, or range of motion among the LP, RIN, and DP techniques. Although analysis did not demonstrate significant differences, it is limited by the lack of the available studies using the DP technique. Additionally, only one study for the NPC technique was retained after screening and data analysis was therefore not possible.

Unconditional optimal [formula omitted]-norm error estimate and superconvergence analysis of a linearized nonconforming finite element variable-time-step BDF2 method for the nonlinear complex Ginzburg–Landau equation

In this paper, a linearized fully discrete scheme combining the variable-time-step two-step backward differentiation formula (VSBDF2) in time and the nonconforming finite element methods (FEMs) in space is constructed and analyzed for the nonlinear complex Ginzburg–Landau equation. A novel convergence analysis approach is proposed, which shows that the H1-norm error of this scheme can reach optimal order in space and sharp second-order convergence in time. The key ingredients of our analysis are temporal-spatial error splitting approach, a new positive definiteness property of discrete orthogonal convolution (DOC) kernels with respect to complex sequences, an energy projection operator and a discrete Laplace operator Δh related to the nonconforming element space, and a relationship between Δh and classical L2 projection operator in complex space. Furthermore, through a specific treatment of the error equation and the combination technique of interpolating operator and projection operator, we prove that the proposed scheme has the global superconvergence result of order O(τ2+h2) in H1-norm for the first time, which further improves the efficiency of numerical computation. Here τ and h are the maximum time and spatial step sizes, respectively. It should be pointed out that all these error results are rigorously established under mild assumptions of the time step, and get rid of the usual grid ratio constraints between temporal and spatial step sizes in linearized scheme. At last, numerical experiments are provided to verify the theoretical analysis.

A Combination Technique for Optimal Control Problems Constrained by Random PDEs

A Combination Technique for Optimal Control Problems Constrained by Random PDEs

Guided Bone Regeneration for the Treatment of Peri-Implantitis: Clinical Case Report

Periodontal disease is characterized as an inflammatory process that damages the periodontal lining and/or support tissues. Peri-implantitis is among the periodontal alterations, being caused by bacterial biofilm causing loss of underlying bone insertion, leading to modifications in its architecture that form intraosseous defects of various types. For the treatment of peri-implantitis there are non-surgical, surgical, resective, regenerative, combined techniques and the decision-making will depend on the degree of the bone defect. Therefore, guided bone regeneration (GBR) is an efficient and simple technique for bone augmentation, which is widely used to restructure bone defects that occur in the alveolar ridge and in the peri-implant region. Biomaterials are alternatives to be used in guided bone regeneration due to their excellent biocompatibility, osteoinductive properties, low degradation rate and their hydrophilicity, which collaborates with the absorption of blood cells and proteins that will help in osseointegration. Female, 58-year-old normosistemic patient, attended a private dental office complaining of pain, bad smell, bleeding and bad taste in the peri-implant region referring to element 25, on its distal face to the mesial face of the element tooth 26. After imaging exams, periodontal probing and the patient's past history, extraction of element 26 was performed, decontamination protocol of the implant surface of 25 through mechanical, chemical and physical means performing antimicrobial photodynamic therapy and finally, a guided bone regeneration was performed, using the allogeneic bone grafting technique associated with a polytetrafluoroethylene membrane in its expanded form (e-PTFE) for recovery of the bone defect and alveolar preservation. Thus, guided bone regeneration has shown high success rates and greater predictability when well indicated and performed, making it important for the maintenance of periodontal and peri-implant health.

CLIMATE AND ENVIRONMENTAL BACKGROUNDS OF FUEL UTILIZATION, INFLUENCING UPON ALTERATION THE EUROPEAN AND UKRAINIAN TRENDS OF GAS SUPPLY. PART 2. PROVIDING THE EFFICIENCY OF FUEL USE IN CONDITIONS OF DECARBONIZATION OF ENVIRONMENT

The paper is dedicated to power and environmental aspects of option the most appropriate types of fuel for supplying the economics of European countries and Ukraine. Accordingly notions about influence of C-containing fuels on greenhouse effect and on warming of environment, the existing tendency of substitution the fossil fuels — generally — and the natural gas — particularly — for methane-hydrogen mixtures is discussed as a controversial point. The problem of advancement the national fuel complexes is under consideration and has been studied with approach based upon the example of Ukrainian pre-war state of economics. An attention has been paid up on reduction of production and consumption of all types of the fossil fuels in the last decades, mainly due lowering the industrial using constituent. An enhancement of fuel using efficiency due improvement of furnace equipment basis provides an successive solution the fuel problems. The thermodynamic background for evaluation the efficiency of fuel using with account of the furnace’s non-ideality has been developed. The problem of “wet combustion” takes of special significance by the reason of weather and climate conditions’ account, on the one hand, and an opportunity to control the efficiency of fuel using, on the other hand, with new combined technique. The contemporary approach consists in combination the direct method of decrease the CO2 emission due exclusion of using the C-containing fuels (firstly — the fossil fuels) and with enhancement the efficiency of using the fossil fuels, for example due erection the recuperative heat recovery facilities with preliminary preheating of combustion air, in some advanced cases by combination with an air, humidification. The perspective ways of provision the decarbonization of environment consists in substitution the fossil fuels (mainly the natural gas NG) for hydrogen or H2-containing gas mixtures. The thermodynamic analysis of relevant technique has been carried out to estimate the opportunities of control the efficiency of hydrogen admixture to NG. Taking into account the variety of technologies of hydrogen production, the engineering method with giving of conditional coloration of hydrogen as a fuel has been considered. The “green” H2 makes the most valuable type of fuel (compared with “blue”, “turquoise”, “yellow”, “rose” colored and especially to the “grey” H2) as a substituting fuel from the standpoint of H2 fitness to process and plant. Particularly for high-temperature melting furnaces a provision of maximum emissivity of flame requires an using of carbon containing fuels to organize thermal pyrolysis of gas and soot formation within the combustion zone. Ref. 44, Fig. 5, Tab. 3.

Source apportionment of fine particulate matter in middle Indo-Gangetic Plain by coupled radiocarbon –molecular organic tracer method

Despite significant emissions of fine particulate matter (FPM) from the Indo-Gangetic Plain (IGP) that affect the climate and air quality in the region, the sources of these emissions are not adequately addressed. This research uses a combined radiocarbon-molecular organic tracer technique to investigate the degree of contamination, seasonal fluctuations, and contribution of FPM in the middle IGP (Patna), India. The findings indicated levoglucosan (L) as the single primary BB tracer chemical, ranging from 149 ng/m3 to 490 ng/m3 (median 282 ng/m3). Winter (median 462 ng/m3) showed a 2–3 times higher level of L than the monsoon season (median 180 ng/m3). A significant association of L with other organic tracers such as galactosan (G), mannosan (M), vallinic acid, syringic acid, p-hydroxybenzoic acid (pHA) and dehydroabietic acid (DHAA)(r = 0.53 to 0.89, p < 0.05), and moderate connection with Cl− (r = 0.21, p < 0.05), SO42− (r = 0.29, p < 0.05), and NO3- (r = 0.22, p < 0.05) indicated significant BB contribution. However, non-sea salt (nss-K+) was not related to L. Based on seven days of air mass back trajectories and MODIS active fire counts analysis, we conclude that OAs composition is not the local origin but is also impacted by long-range atmospheric transport from Pakistan/Afghanistan, followed by the Bay of Bengal and the Arabian Sea. Chemical analysis of organic tracers and positive matrix factorization (PMF) modeling study identified three unique sources, i.e., biomass burning, secondary aerosols formation, and mixed type (fossil fuels and construction dust) as the primary source of FPM in Patna, accounted for 46.1 %, 28.9 %, and 24.9 %, of total emissions, respectively. The radiocarbon (14 C) analysis of total carbon (TC) samples further supported this conclusion. The results of the 14 C study indicated that emissions from BB, such as wood and stubble, were responsible for 57% of the TC concentration.

Nonlinear radiative thermal analysis of magneto-micropolar fluid over a bidirectionally extending sheet with varied thermal conditions

Thermal fluid flow analysis occasioned by stretching surfaces offers practical industrial and engineering applications, such as extrusion and drawing processes and materials experiencing heating and cooling conditions. Thus, this study explores magnetohydrodynamic micropolar fluid flow under varied thermal conditions and nonlinear thermal radiation over a dually stretched sheet subject to surface mass flux and an internal heat source. The study thus provides insight into the dynamics of heat transfer mechanisms for improving material processing techniques in many engineering processes. The flow dynamics with the thermal analysis are evaluated by applying two thermal conditions in the heat equation: the prescribed surface temperature (PST) and the prescribed heat flux (PHF). The formulated partial derivative equations that describe the current problem are changed into ordinary derivatives using some similarity quantities, while the converted equations are tackled with the combined techniques of shooting and Runge–Kutta Fehlberg. Consequently, diverse tables and figures are displayed to deliberate on the impacts of the physical terms on the dynamics of flow and heat transmission processes. The consequence of the analysis reveals a higher heat gradient in the prescribed surface temperature case than the uniform temperature distribution, as the Prandtl number magnifies. The micropolar material term reduces the surface frictional factor and depletes heat transmission, but the magnetic field term raises the skin friction coefficient.

A case report on the use of combined spinal epidural technique in the anaesthetic care of a patient with a large ASD and severe pulmonary hypertension

A defect in the septum between the left and right atrium is known as atrial septal defect which is a congenital heart disease. The defect causes shunting of blood from left to right side of the heart, increasing the blood flow through the lungs. Small atrial septal defects may be found incidentally and never cause a major concern. Larger defects may damage the heart and also the lungs. The use of combined spinal and epidural technique in a patient with ASD can maintain hemodynamic stability, provide perioperative analgesia and also avoid the hemodynamic perturbations associated with general anaesthesia in a patient with severe pulmonary hypertension.

Ultra-small cesium silver bismuth bromide quantum dots fabricated by modified hot-injection method for highly efficient degradation of contaminants in organic solvent

Lead-free halide perovskite material has drawn fast-growing interest due to its superior solar-conversion efficiency and nontoxic nature. In this work, we have successfully fabricated cesium silver bismuth bromide (Cs2AgBiBr6) quantum dots utilizing the hot injection method. The as-synthesized quantum dots were characterized by combined techniques, which showed remarkable visible-light photocatalytic activity for organic dyes and antibiotic degradation in ethanol. Specifically, about 97% of rhodamine B and methyl orange may be removed within 10 min and 30 min, respectively. Additionally, 60% of antibiotic residue of tetracycline hydrochloride is degraded in 30 min which is 7 times more than that on commercial titania (P25). The reactive species for the photodegradation are determined through capture experiments, and a reaction mechanism is proposed accordingly. This work provides a novel photocatalyst for the selective removal of diverse organic contaminants in ethanol and an alternative for the potential application of lead-free halide perovskites.

Labouring on a journey in conceptualising a needs-based induction (NBI) programme: An Autoethnographic reflections and experiences

This autoethnographic (AE) paper draws directly from a national collaborative project called the New Academics Transitioning into Higher Education Project (NATHEP), which is funded by the University Capacity Development Grant (UCDG). We adopted evocative and narrative AE methodology to confront, interrogate, and uncover our own biases, assumptions, and preconceptions of induction before NATHEP, how it is now, and how it should be understood and conducted after being part of the NATHEP project. Our AE showcases our critical and reflective thoughts on the learning acquired throughout the journey, consciously and intentionally asking ourselves whether the NATHEP journey was worth it and how it benefitted the induction programme we conceptualised and implemented. Through a combined autoethnography study design and technique, we were able to gather qualitative data from the two of us and present it as written reflective narratives. Together, we developed an open-ended questionnaire in which we asked questions that sought to elicit our experiences throughout the journey as a way of reflecting on the overall learning acquired by being part of the NATHEP project. Our responses and narratives are reflectively and thematically analysed to make sense of how we interpret our eventful NATHEP journey thus far. We conclude and submit that this paper has implications for academic development practice and academic developers who aspire to be reflective practitioners, constantly reflecting on their practices to dismantle and disrupt cultural tendencies in their quest to transform their context of work and induction practices.

Genetic analysis of two families with abnormal findings upon prenatal diagnosis

To carry out genetic analysis on two families with carriers of small terminal translocations using karyotyping analysis and genomic copy number variation sequencing (CNV-seq). Two couples undergoing prenatal diagnosis at the Tianjin Central Hospital of Obstetrics and Gynecology respectively on April 12, 2020 and December 17, 2021 were selected as the study subjects. With informed consent, amniotic fluid and peripheral blood samples were collected and subjected to conventional karyotyping and CNV-seq analysis for the detection of chromosomal microdeletion/duplications. Both couples had given births to children with chromosomal aberrations previously, and both fetuses were found to have abnormal karyotypes. CNV-seq showed that they had harbored microdeletion/duplications, and their mothers had both carried balanced translocations involving terminal fragments of chromosomes. For fetuses with small chromosomal segmental abnormalities, their parental origin should be traced, and the diagnosis should be confirmed with combined genetic techniques.

Exploring Human Emotions: A Virtual Reality-Based Experimental Approach Integrating Physiological and Facial Analysis

This paper researches the classification of human emotions in a virtual reality (VR) context by analysing psychophysiological signals and facial expressions. Key objectives include exploring emotion categorisation models, identifying critical human signals for assessing emotions, and evaluating the accuracy of these signals in VR environments. A systematic literature review was performed through peer-reviewed articles, forming the basis for our methodologies. The integration of various emotion classifiers employs a ‘late fusion’ technique due to varying accuracies among classifiers. Notably, facial expression analysis faces challenges from VR equipment occluding crucial facial regions like the eyes, which significantly impacts emotion recognition accuracy. A weighted averaging system prioritises the psychophysiological classifier over the facial recognition classifiers due to its higher accuracy. Findings suggest that while combined techniques are promising, they struggle with mixed emotional states as well as with fear and trust emotions. The research underscores the potential and limitations of current technologies, recommending enhanced algorithms for effective interpretation of complex emotional expressions in VR. The study provides a groundwork for future advancements, aiming to refine emotion recognition systems through systematic data collection and algorithm optimisation.

A REVIEW OF AQUATIC PLANT BIOMASS PRETREATMENT METHODS FOR BIOGAS PRODUCTION

The increasing global demand for renewable energy sources has led to interest in generating biogas from aquatic plant biomass. This research examines the pretreatment methods of biomass, aiming to enhance the efficiency of biogas production processes. The analysis presents mechanical, chemical, biological, or combined pretreatment techniques, assessing their respective advantages, limitations, and potential synergies. The review extends beyond individual methodologies to identify potential synergies or sequential applications that could maximize biogas production efficiency. This study ultimately facilitates moving the field forward, contributes to the transition to more sustainable energy solutions, identifies gaps in existing researches, paving the way for future investigations and combat to solve upcoming energy problems.

Use of Optical and Radar Imagery for Crop Type Classification in Africa: A Review.

Multi-source remote sensing-derived information on crops contributes significantly to agricultural monitoring, assessment, and management. In Africa, some challenges (i.e., small-scale farming practices associated with diverse crop types and agricultural system complexity, and cloud coverage during the growing season) can imped agricultural monitoring using multi-source remote sensing. The combination of optical remote sensing and synthetic aperture radar (SAR) data has emerged as an opportune strategy for improving the precision and reliability of crop type mapping and monitoring. This work aims to conduct an extensive review of the challenges of agricultural monitoring and mapping in Africa in great detail as well as the current research progress of agricultural monitoring based on optical and Radar satellites. In this context optical data may provide high spatial resolution and detailed spectral information, which allows for the differentiation of different crop types based on their spectral signatures. However, synthetic aperture radar (SAR) satellites can provide important contributions given the ability of this technology to penetrate cloud cover, particularly in African tropical regions, as opposed to optical data. This review explores various combination techniques employed to integrate optical and SAR data for crop type classification and their applicability and limitations in the context of African countries. Furthermore, challenges are discussed in this review as well as and the limitations associated with optical and SAR data combination, such as the data availability, sensor compatibility, and the need for accurate ground truth data for model training and validation. This study also highlights the potential of advanced modelling (i.e., machine learning algorithms, such as support vector machines, random forests, and convolutional neural networks) in improving the accuracy and automation of crop type classification using combined data. Finally, this review concludes with future research directions and recommendations for utilizing optical and SAR data combination techniques in crop type classification for African agricultural systems. Furthermore, it emphasizes the importance of developing robust and scalable classification models that can accommodate the diversity of crop types, farming practices, and environmental conditions prevalent in Africa. Through the utilization of combined remote sensing technologies, informed decisions can be made to support sustainable agricultural practices, strengthen nutritional security, and contribute to the socioeconomic development of the continent.