Search

Summary This is the second of a three-part series that charts the history of minimal access surgery from antiquity to current times. Although rapid developments in laparoscopic and robotic surgery have transformed surgical care over the last 30 years, our predecessors made significant advances in their time which set the principles for modern practice. Part I of this series described how ancient medical practitioners developed simple instruments, from metal or wood, for viewing body cavities. Improvements in the use of metal, glass and lighting allowed for inspection of deeper parts of the body. This second part of the series will show how advances in electrical technology allowed the development of improved lighting for endoscopy and laparoscopy along with the use of electrocautery for a wide range of therapeutic procedures.

This paper studies the coordinated use of smart inverters with legacy voltage regulating devices to help increase the energy savings from conservation voltage reduction (CVR) in distribution systems with high photovoltaic penetration. Two voltage optimization algorithms are developed to evaluate the CVR benefit by considering two types of smart inverter functions: aggregated reactive power control and autonomous volt/VAR control. In each algorithm, smart inverters are coordinately controlled with the operation of legacy voltage regulating devices including load tap changers and capacitor banks. Both algorithms are tested on representative utility distribution system models. Simulation results demonstrate that the proposed algorithms can achieve around 1.8-3.6% energy savings when only using legacy voltage regulating devices and an additional 0.3-0.9% when adding smart inverters.

PurposeThis study aims to assess and decompose the sustainable development using the 17 sustainable development goals (SDGs) in Iran in 2018, for proposing agenda-setting of public policy.Design/methodology/approachIt ranks the SDGs not only in Iran but also in the region and the world to reveal the synergetic effects.FindingsBased on the results, subaltern-populace generally suffers from the hegemonic domination of ruling elite-bourgeois, lack of strong institutions, heterogeneous policy networks and lack of advocacy role of non-governmental organizations, due to no transparency, issues in law or no rule of law, no stringent regulation, rent, suppression and Mafia, all leading to corruption and injustice.Practical implicationsTo stop the loop of corruption-injustice, Iran should homogenize the structure of the policy network. Furthermore, the failed SDGs of the three-geographic analysis are the same in a character; all of them propose SDG 3, good health and well-being as a serious failed goal.Social implicationsIn this regard, strong evidence is the pandemic Coronavirus, COVID 19 since 2019, due to its highly-disastrous consequences in early 2020 where the public policymakers could not adopt policies promptly in the glob, particularly in Iran.Originality/valueIn Iran, in addition to this, the malfunction of health is rooted in “subjective well-being” and “traffic deaths,” respectively. Concerning the transportations system in Iran, it is underscored that it is damaging the sustainable development from all the three pillars of sustainable development including, economic, social and environmental.

У статті наведено рівняння для дослідження залежності напруженості електричного поля в біологічно активних точках від параметрів радіоімпульсного випромінювання. Отримані результати дозволили провести аналіз якісних властивостей процесу взаємодії радіоімпульсного випромінювання з біологічно активними точками. Було запропоновано біологічно активні точки розглядати як діелектричний резонатор, поміщений в плоску діелектричне середовище. Тому, якщо частота заповнення радіоімпульсу близька до власної частоти такого резонатора, то можливо резонансне збільшення напруженості електричного поля в біологічно активних точках. При проведенні численних розрахунків було прийнято, що сумарний потенціал на мембрані біологічних клітин не повинен перевищувати величину в 100 мВ. У процесі теоретичного аналізу розробленої моделі було встановлено, що для підвищення життєздатності новонароджених телят хворих диспепсією їх біологічно активні точки слід опромінювати інформаційним радіоімпульсного випромінюванням в діапазоні змін параметрів: тривалість імпульсів 0,5 · 10-7 ... 1,5 · 10-7 с; період проходження імпульсів 0,5 · 10 .... 1,5 · 10-5 с; величина щільності потоку потужності 15 мкВт / см2; частота заповнення імпульсів 50ГГц; час експозиції 15 ... 20 с; напруженість електричного поля E0 = 8,8 В / м, Еср = 5,7 В / м.

Introduction. To represent our national goods at the Western market it is necessary to ensure, first of all, the competitiveness of local products through complex mechanization of technological processes, labour costs reduction, increasing yields and quality of received products. The aim of the research is to provide the comparative analysis of technology and machines for potato harvesting, to determine the main factors that influence the agricultural technical indicators of harvesting equipment, to develop technological process patterns and to examine the strategies for improving the potato root-and-harvest machines. Methods and methodology. The research was carried out on the basis of technological and constructional analysis of technology and machines for potato harvesting. The methods of comparison and mathematical modelling of technological processes were used in the study. The research studies of Ukrainian and foreign scientists on technology and machines for potato harvesting were used as information base of our paper. Results. A comparative analysis of technology and machines for potato harvesting made it possible to determine the main factors that influence the agricultural performance of harvesting machinery and to develop the technological process for a digger, a double-loader digger and a harvester (harvesting machines). A theoretical model of the technological processes of harvesting machines includes both uncontrolled and controlled factors that influence the choice of a potato harvesting technology of a digger, a double-loader digger and a harvester. Nevertheless, the first factors are connected, primarily, with the conditions of potato growth and its biological properties, and the second factors deal with the organizational and technical measures, including the improvement of the working bodies of machines (cutting, dirt digging through, top separation, longitudinal hump with cut roller and other constructive and kinematic parameters), quality of received products, length and terms of potato storage, available farming human resources, free vehicle in the period of harvesting, farm potato storage, farm equipment for potato cleaning and sorting.

Tree fruit architecture results from combination of the training system and pruning and thinning processes across multiple growth and development years. Further, the tree fruit architecture contributes to the light interception and improves tree growth, fruit quality, and fruit yield, in addition to easing the process of orchard management and harvest. Currently tree architectural traits are measured manually by researchers or growers, which is labor-intensive and time-consuming. In this study, the remote sensing techniques were evaluated to phenotype critical architectural traits with the final goal to assist tree fruit breeders, physiologists and growers in collecting architectural traits efficiently and in a standardized manner. For this, a consumer-grade red–green–blue (RGB) camera was used to collect apple tree side-images, while an unmanned aerial vehicle (UAV) integrated RGB camera was programmed to image tree canopy at 15 m above ground level to evaluate multiple tree fruit architectures. The sensing data were compared to ground reference data associated with tree orchard blocks within three training systems (Spindle, V-trellis, Bi-axis), two rootstocks (‘WA 38 trees grafted on G41 and M9-Nic29) and two pruning methods (referred as bending and click pruning). The data were processed to extract architectural features from ground-based 2D images and UAV-based 3D digital surface model. The traits extracted from sensing data included box-counting fractal dimension (DBs), middle branch angle, number of branches, trunk basal diameter, and tree row volume (TRV). The results from ground-based sensing data indicated that there was a significant (P

In an effort for further improvement of LSCF hollow fiber membrane properties in oxygen purification application, this work studied the use of polyethylene glycol (PEG) with different molecular weight of 2000, 3400 and 6000 Da as a pore former. A well-prepared hollow fiber membrane was successfully fabricated via extrusion followed by a sintering method. The results showed that the addition of PEG increased the viscosity of the dope suspension and formed a constant asymmetric pore configuration of the membrane after sintering at 1250 °C. The increasing molecular weight of PEG also leads to a decrease in the mechanical strength of the membranes, indicating that finger-like pores were sacrificed by forming irregular pores. The gas tightness was also examined under room temperature which showed that membrane with PEG 3400 achieved the best tightness with the nitrogen permeability of 3.55 × 10−5 mol·m−2·s−1·Pa−1. The oxygen permeation of the membranes was also influenced by the addition of PEG, where the highest oxygen permeation flux of 6.07 × 10−8 mol·cm−2·s−1 was obtained using a hollow fiber membrane with PEG 3400 due to the existence of the lowest dense layer thickness.

Results of fourteen two-span continuous deep beams those made from ordinary reinforced concrete (ORC) as a reference and rubberized reinforced concrete (RRC) are presented and discussed in this research. The main parameters are the rubber ratios as a replacement with coarse and fine aggregate and shear span/depth ratio (a/h) is 1.33 and 1.66. Chip and crumb rubbers were used to replace coarse and fine aggregate respectively in four different amounts by volume (5%, 10%, 15%, and 20%). The proposed mix shows an ability to replace 20% of the aggregate (coarse or fine), and the production is still structural concrete. All beams design to fail in shear. The main crack is formatted between the intermediate support and the applied load diagonally. In spite of the inclusion of waste tire rubber in concrete has specific apparent degradations, the potential benefit seems to overlook the adverse effects and also provides the primary significant value of resolution for rubber waste problems. The results show that 20% volumetric substitution of natural coarse or fine aggregates with tier rubber reduced the ultimate load of continuous deep beams by 32.06% and 32.65% but significantly increases the ultimate deflection by 83.07% and 106.28% respectively. The ductility of rubberized continuous deep beams increases up to 36.95% when the replacement ratio of crumb rubber is 20%.

Amidst a world of never-ending waste production and waste disposal crises, scientists have been working their ways to come up with solutions to serve the earth better. Two such commonly found trashes deteriorating the environment are glass and tin can waste. This study aims to investigate the comparative suitability of response surface methodology (RSM) and artificial neural network (ANN) in predicting the mechanical strength of concrete prepared with fine glass aggregate (GFA) and condensed milk can (tin) fibers (CMCF). An experimental scheme has been designed in this study with two input variables as GFA and CMCF, and two output variables as compressive and splitting tensile strength. The results show that both variables influenced the compressive and splitting tensile strength of concrete at 7, 28, and 56 days (p

A novel Log periodic patch with circular slot antenna has been presented here, the perturbation of shape of antenna has been done by combining a triangular shape with a semicircular shape. The antenna proposed here is with a DGS structure on its ground plane and its effects on band width and gain enhancement of the antenna is analyzed. The substrate of FR-epoxy material with length, breadth and height 170 mm, 50 mm and 1.6 mm, respectively is taken for implementation of the antenna on it. This proposed antenna operates at 12 GHz to 18 GHz that includes Ku-band with return loss below-10 dB. The parameters of antenna like S-parameters, antenna gain, directivity, VSWR, surface current distribution and radiation efficiency are determined one by one to ascertain its better performance. The simulation as well as the measurement results are comparatively analyzed.

The compatibility problems become main concern in the utilization of biodiesel especially regarding to degradation and corrosion. The present study is conducted to describe the corrosion behaviour that occurs in steel tanks after contact with palm-based biodiesel for a period of 7 months. The storage tank used is respectively made of galvanised steel (GS), carbon steel (CS) and stainless steel (SS). It is performed in vertical cylinders with a floating-roof model. In every 30 days of storage time, the profile changes in the wall, roof and base surface of each tank were observed. The oil fuel properties were monitored in the parameter of viscosity, acid numbers, water content and oil colour. The topographic profiles on the surface of the walls and bottom of each tank wetted by biodiesel were examined over three zones inside the tanks using an endoscope imager. The main results of this study indicate that the tank steel with different protective layers exhibits different types of corrosion. The corrosion was localized in SS tanks but generalized in GS and CS tanks. The oil contamination in SS tanks was relatively lower than that in CS and GS tanks. The type of corrosion performed differently in different zones on the inside of the tank. The potential for leaks is greater at the base than on the walls and roof of the storage tank.

Monitoring the degradation of induction motors is an essential concern for industries, especially when there are high costs related to maintenance and their stops. Nowadays, there are many non-invasive ways to monitor the health status of induction motors, including sensors to measure temperature, magnetic field, vibration, current, and power. However, installing these sensors may not be a simple task since intrusive procedures such as engine disassembling, wire separation, and engine interruption are commonly observed. Thus, we propose MUCLA (Multiphase Clamp and Tracking - patent pending) as a new device and methodology for monitoring motor degradation by analyzing its stator current. MUCLA introduces a non-invasive current sensors array on a proposed clamp in the hardware perspective, while a spectral tracking methodology refers to our novelty in the software viewpoint. For end-users, the main MUCLA contribution relies on the combination of the simplicity of installation and the possibility of using the proposed device even when considering Variable-Frequency Drive powered engines. The results obtained with both simulation and practical tests show encouraging results over different input workloads and emulated degradation. Compared to the current initiatives, we can classify MUCLA as a better solution for industrial plants in terms of installation time, installation complexity, and cost.

The reliability of the result significantly affects the use of the Coefficient of Variation (within the test variation), which reflects the variability of the concrete properties rather than the standard deviation. For the estimation of reliability and precision, comprehensive statistical analysis (within test variation) is conducted on 534 test samples using a rebound hammer. Different standards, like BIS, EN, ACI, and ASTM, are used in this study to compare the test results. Empirical research revealed that there are contradictions in literature as well as the standards used in many countries. The present paper focuses on detailed investigations of uncertainty measurements of the surface hardness test by statistical parameters (range of rebound index, standard deviation, and Coefficient of Variation). The unbiased estimate of the variability parameters from the published results has been verified concerning to the European standard. Concrete parameters namely cement type, water to cement ratio, compaction deficiency, curing condition, and elevated temperature have an impact on the output of the rebound hardness in terms of the variability of the compressive strength. Based on the results, the authors are willing to propose amendments to the Indian code graciously in compliance with the variability of the rebound hammer.

Using oil futures, we examine expectation formation and how it alters the macroeconomic transmission of shocks. Our empirical framework, where investors learn about the persistence of oil-price movements, successfully replicates the fluctuations in oil-price futures since the Late 1990s. By embedding this learning mechanism in an estimated model, we document that an increase in the persistence of TFP-driven fluctuations in oil demand largely accounts for investors' perceptions that oil-price movements became increasingly permanent during the 2000s. Learning alters the macroeconomic impact of shocks, making the responses time dependent and conditional on perceptions of shocks' likely persistence.

Today there is a rapid development taking place in phenotyping of plants using non-destructive image based machine vision techniques. Machine vision based plant phenotyping ranges from single plant trait estimation to broad assessment of crop canopy for thousands of plants in the field. Plant phenotyping systems either use single imaging method or integrative approach signifying simultaneous use of some of the imaging techniques like visible red, green and blue (RGB) imaging, thermal imaging, chlorophyll fluorescence imaging (CFIM), hyperspectral imaging, 3-dimensional (3-D) imaging or high resolution volumetric imaging. This paper provides an overview of imaging techniques and their applications in the field of plant phenotyping. This paper presents a comprehensive survey on recent machine vision methods for plant trait estimation and classification. In this paper, information about publicly available datasets is provided for uniform comparison among the state-of-the-art phenotyping methods. This paper also presents future research directions related to the use of deep learning based machine vision algorithms for structural (2-D and 3-D), physiological and temporal trait estimation, and classification studies in plants.

In regions such as hawai'i, south australia, Tasmania, Texas, and Ireland, power systems are commonly experiencing instantaneous penetration levels of inverter-based power sources (IBPSs) such as wind, solar photovoltaics (PV), and battery storage in excess of 50n60% relative to system demands.

Secure, Clean, and Efficient Energy is one of the great societal challenges of our time. Electricity as a sustainable energy carrier plays a central role in the most effective transition scenarios toward sustainability. To harness this potential, the current electricity infrastructure needs to be rigorously re-engineered into an integrated and intelligent electricity system: the smart grid. Key elements of the smart grid vision are the coordination mechanisms. In such a system, vast numbers of devices, currently just passively connected to the grid, will become actively involved in system-wide and local coordination tasks. In this light, transactive energy (TE ) is emerging as a strong contender for orchestrating the coordinated operation of so many devices.

Battery energy storage effectively staBIlizes the electric grid and aids renewable integration by balancing supply and demand in real time. The importance of such storage is especially crucial in densely populated urban areas, where traditional storage techniques such as pumped hydroelectric energy storage and compressed-air energy storage are often not feasible.

In this study, CO₂ conversion to acetate and CH₄ was achieved in a flow-through laboratory-scale microbial electrosynthesis (MES) cell composed of a 3D conductive polylactic acid (cPLA) lattice cathode with electrodeposited metal electrocatalyst coatings. The MES cell with a bare cPLA cathode showed the poorest performance with the lowest H₂ and CH₄ production rates and low Coulombic efficiency. This was ascribed to a poor electrocatalytic activity of cPLA towards H₂ production and high electrode resistivity. When the cPLA electrode was modified with metal coatings, the CH₄, acetate and H₂ production rate increased significantly, with the following trend: cPLA < Ni < NiFe < NiFeMn. The better performance of the metal-coated cPLA in terms of CH₄ production was attributed to the lower electrical resistance, enhanced H₂ production and enhanced electron transfer between the cathode and the biofilm. At the cell potential of 2.8 V, the best-performing NiFeMn cPLA cathode showed stable production of CH₄ (50 ± 6 mL d⁻¹), acetate (185 ± 27 mg d⁻¹), and H₂ (545 ± 175 mL d⁻¹) at close to 100% Coulombic efficiency.

Determining the properties of mine waste dump material is very difficult, it is caused by the difference of dimension between the laboratory equipment and field material size distribution. This study aims to determine the material properties from mine waste dump material using back analysis method after failure was occurred. The back analysis method is based on a trial and error concept which focuses on failure geometry and it is conducted by varying the cohesion and friction angle until the safety factor was less than 1.0. The laboratory results showed a 66.2 kPa change as well as a 48.8°friction angle deviation in mine waste dump material properties, while the back analysis indicated 33.7 kPa and 27.4°. It means, there is a reduction in the value. Therefore, the increasing in these properties are expected to allow the redesign of heap stability.

Cooling enhances the energy conversion efficiency and output of photovoltaic (PV) panels. In this work, the effects of natural convection, forced convection, and evaporative cooling on the performance of polycrystalline PV panels were investigated. The output and efficiency of a cooled PV panel were monitored and compared to those of an uncooled PV panel under the same conditions. The cooling was conducted using an insulated channel installed below a PV panel. Natural convection cooling was investigated for various channel air gaps (H = 30, 60, 90, and 120 mm). Natural convection currents in the cooling channels were capable of cooling the panel with wide air gaps. In forced convection cooling, the air was introduced by fans installed at the bottom opening of the cooling channel with various air velocities (ua = 1, 2, and 3 m/s). Evaporative natural convection cooling was performed by a wetted fabric along the lower surface of the cooling channel, whereas evaporative forced convection cooling by pushing air along the wetted lower surface of the channel. The experimental data showed that the panel efficiency and output increased due to cooling. The experimental results of natural convection cooling revealed that the use of an air gap of 120 mm to cool the solar panel contributed to an increase in the panel daily energy production and efficiency by 1.7% and 1.2%, respectively. For forced convection cooling, using air at a speed of 3 m/s increased the daily energy production by 4.4% and the efficiency by 4%. Natural convection evaporative cooling increased the daily energy production and the efficiency by 3.6% and 2.7%, respectively. Forced convection evaporative cooling contributed, at a speed of 2 m/s, to an increase in the daily energy production by 3.8% and an increase in efficiency of 3.8%.

Energy management strategy is gaining much popularity due to the involvement of conventional/non-conventional power sources with an efficient energy storing solution to offer un-interruptible power demand. Thus, in this work a simpler logic control circuit based nonisolated bi-directional DC-DC converter with both battery and super capacitor topology is proposed. For the proposed topology, first its mathematical modelling in ideal-case with parasitic in every mode of actions is presented. To control the bidirectional DC-DC converter topology, its small signal model for individual buck and boost operation is obtained by using averaging and linearization technique. Then, a unified logic circuit-based controller is designed for the obtained systems to analyze the performance of the converter in the buck and boost mode operation. The performance of the proposed topology is verified through MATLAB/Simulink environment.

Superplasticiser (SP) is widely used in foam concrete industry to improve rheological properties since compaction and vibration adversely affect the stability of foam bubbles. This study aims to investigate the effect of polycarboxylate SP contents on the properties of foam concrete. Different water-cement ratios (w/c) were used, and the SP added to the mixture to adjust the spreadability. The density of 1500 kg/m3 was chosen for the production of foam concrete for semi-structural applications. Fresh, mechanical, transport and microstructure properties were analysed in this study. The results of this study showed that the content of w/c and SP had a significant impact on the performance of the foam concrete. Increasing the SP content enhanced the foam concrete’s mechanical and transport properties, but the best behaviour was through the use of 1.35% of SP. Smaller pore diameter, better pore distribution and higher portlandite peak intensity were achieved through the use of the SP. Overall, the superior behaviour of the foam concrete was achieved by the use of 1.35% polycarboxylate SP.

A new dc-dc converter with high voltage gain is proposed in this study. The proposed converter consists of two switches which are turned on and off simultaneously. Additionally, two Switched-Capacitor (SC) cells and one Energy Storage (ES) cell are utilized in the structure of the proposed converter. These result in high voltage gains at low values of the duty cycle. Besides, the voltage stress across the power devices is low and below half of the output voltage. Therefore, the MOSFET switches with low RDS-on and devices with reduced nominal voltage can be used in the proposed converter which in turn reduces the conduction and turn-on losses. The analysis of the voltage and current stresses of the devices is accomplished. The circuit performance is compared with other solutions in the literature in terms of voltage gain and normalized voltage stress of switches and diodes. Eventually, in order to verify the theoretical analysis, the experimental results are provided.

According to scientific studies dealing with the statistics of ICE (internal combustion engine) failures, most of them are registered in the ignition system (25%) and the power system (35%). The operable state of the ICE fuel system can be maintained by developing effective testing methods. For the purpose of theoretical research, a DBD-4 testing device was designed in the methodological part of the research. The use of the developed methodologies and instrumentation allowed carrying out experimental studies to diagnose the operability of the fuel supply system. Analyzing the obtained experimental data, it can be affirmed that: there is a stable relationship between the change in the ICE crankshaft speed and the change in the injection duration of the electromagnetic injector; the degree of wear of the electric fuel pump (EFP) is determined by the shift of the stable value of the crankshaft speed to the zone of low speed values at the same injection durations. The data obtained after testing the EFP allows planning a further algorithm of actions to maintain the operability of the fuel supply system.

This paper describes a statistical and mathematical approach to optimize the mechanical properties of a wood plastic composite with Polyethylene Terephthalate (PET) as polymeric matrix. Wood plastic composite are materials that consist of a primary continuous polymer phase, where a secondary filler dispersed phase is embedded, the filler generally is wood fibers or sawdust. The slack variable approach in mixture experiments, consist in selecting a component of the mixture as slack variable, to subsequently design and analyze the experiment in terms of the remaining components. With the experimental design information three slack variable model were fit. Using response surface graphs, we show how different compositions modify the mechanical properties of wood plastic composite. Besides, by the desirability function, the optimal formulation of the compound that simultaneously maximizing the mechanical properties of wood plastic composite, was obtained. Finally, the components proportions that provides the best tensile, flexural and compression strength are presented.

This paper explores the potential of water jet eductor to replace large condensers and vacuum pump in the thermal desalination systems, with heat source temperatures below 95 °C. The operational limit of eductor has been investigated for active vapor transport and condensation to produce permeate. Combined system and its operational principle have been proposed with critical examination based on suction performance of Eductor. Experimental and computational study are the primary methodology of this work. The computational analysis of single-phase flow in Eductor, is in proper agreement with the experimental data. The result showed primary pressure & area ratio has positive impact and swirl ratio has negative impact on suction. The extended thermal analysis summarizes strength of Eductor while working with lower temperature sources and optimum cooling capacity of proposed system. Considering the simplicity and reduction in footprint, proposed application has been highlighted. The research disseminates knowledge on maximum vacuum generation capacity of Eductor and operational limit of thermal desalination system.

Waste management has become a new challenge for the construction industries since rapid urbanization is taking place worldwide. Ceramic waste is one such material which is being originated from construction sites and industries, imposing a significant risk to the environment due to its non-biodegradable nature. With the goal of waste utilization, this study aims to predict the compressive and splitting tensile strength of concrete made with waste Coarse Ceramic aggregate (CCA) and Nylon Fiber (NF) by using two distinct machine learning algorithms, namely, Support Vector Machine (SVM) and Gradient Boosting Machine (GBM). A comprehensive data set for testing and training the models containing 162 records of compressive and splitting tensile strength test results were considered from nine mix proportions. For training the dataset, parameters like cement content, sand content, stone content, ceramic content, nylon fiber content, curing duration, and concrete strength were taken as input variables. The predicted strengths obtained from the SVM and GBM based models are found to be in close agreement with the experimental results. In terms of coefficient of determination (R2), GBM showed significantly better result for both compressive strength (e.g., SVM Overall R2 = 0.879 & GBM Overall R2 = 0.981) and tensile strength (e.g., SVM Overall R2 = 0.706 & GBM Overall R2 = 0.923) prediction. Furthermore, based on the statistical accuracy measures like the mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE), it has been observed that GBM has yielded much better performance compared to SVM in predicting the mechanical strength of concrete.

Smart materials have played significant contribution towards the development of buildings. There are various smart materials which can change their properties and behavior under the influence of external catalyst or stimulus. Such materials are changing the face of traditional engineering materials. Smart materials can be utilized individually as well as it can be incorporated with existing materials to enhance their desirable properties. Smart materials are widespread across all the domains of human inventions due to its multidisciplinary applications. Some of these materials are relatively new while some are being used from a very long time. Hence it suffices to say that the recently developed smart materials still require research. The general classification of smart material is illustrated in this review paper. The paper intends to identify the various types of available smart materials and also illustrated the application of such materials in the various fields of civil engineering. Further, the potential benefits and downsides are also discussed along with their applicability under different conditions. Some innovative materials are also discussed which can bring potential revolution in the construction industry. The impact or the benefits related to sustainability also discussed in this review paper.

One-level optimization methods have been proposed to optimize a single user’s load profile or a cluster of users in the smart grids. In this work, two two-level optimization methods are studied, one case considering technical requirements (case 1) and another considering economic criterion (case 2). In the upper level, the supplier optimizes the objective function. Meanwhile, at the lower level, users optimize their electrical costs. The proposed methods are based on Genetic Algorithm methods. In this sense, an indirect control is established in which users react to a price signal. Simulation results illustrate that both cases improve the demand profile and increase the retailer profit concerning an unscheduled case. However, when the supplier tries to maximize the profit, some users receive benefits to detriment of others, concluding that the technical approach is preferable to the economic one.

A case study of the steel–concrete composite structure in the Pidie Jaya Regency Multipurpose Hall which experienced substantial permanent lateral deformation due to the effect of an earthquake is presented in this study. Therefore, it is important to assess the response of the structure to earthquake load and propose the strengthening strategies to make the buildings useful again. The purpose was to evaluate the causes of large deformations and the behavior of structure in resisting earthquake loads. The building structure model used in this study is a space frame with two-column base support conditions which are fixed and hinged supports after which a non-linear time history analysis was conducted. The time history analysis was conducted using five ground motion acceleration data recorded during earthquakes to determine the deformation and it was found that the large structure permanent deformation was due to the small structure stiffness in the direction of the deformation due to the use of only one column row in front of the building. Moreover, hinged support was observed to have caused a greater deformation than fixed support but was found not to be the main cause of large permanent deformation of the structure. The building structure was further strengthened by adding 4 columns while the oblique columns remained in a sloping condition. Meanwhile, the response spectrum analysis showed the strengthening structure was able to withstand earthquake loads with less deformation than the required standard.

A cost-effective stereolithography for medium-scale components is developed to fabricate 3D components with high build speed and resolution from photo-curable resin. The developed SLA utilizes a focused light beam of wavelength range (300 nm–700 nm) coming from the DLP projector and passes through the objective lens and finally imposed on the platform containing a layer of photo-curable resin. After focusing the light beam on the liquid resin layer, the photo-polymerization reaction occurs and the liquid resin becomes solid. Thus, the 3D object is fabricated layer by layer curing of liquid resin. The photopolymer used in this experimentation is polyethylene glycol di-acrylate and Irgacure 784 as photo-initiator. The Creo 3.0 software is used for modelling of 3D objects. A special MATLAB code is developed for slicing of the 3D model and displaying the sliced image one by one through DLP projector. The Arduino microcontroller with stepper motor and ball screw is used to control the motion of Z-stage platform. The Creation workshop software is also used to control motion of the Z-stage and period to display the sliced images through DLP projector. The medium-scale 3D objects with rectangular, square, and circular cross-sections are obtained by curing the aforementioned photo-curable resin. It is observed that the 3D objects are best cured for two seconds curing time with 0.1 mm curing depth along Z-axis.

Agriculture waste such as sugarcane bagasse (SCB) is composed mostly of cellulose, a very versatile natural biopolymer with well-established applications in many industries. The purpose of this study was to use combination treatment methods which include alkaline treatment and mild acid hydrolysis assisted with ultrasonication to extract cellulose nanofibers (CNFs) from sugarcane bagasse. Initially, the SCB fibers were treated with sodium hydroxide and aqueous hydrogen peroxide, a bleaching agent before subjected to mild acid hydrolysis followed by ultrasonication at 70% amplitude to defibrillate and disperse the fibers. The study focused on acid hydrolysis using mild sulfuric acid to the alkaline treated cellulose fibers extracted from SCB. The FESEM images of isolated CNFs exhibited diameter in the range 20–30 nm and length of up to several micrometers. This observation suggests that the combined treatment methods are highly effective in isolating CNFs from the plant biomass. Moreover, XRD analysis reveals the presence of peaks at 2θ of 15.2° and 22°, indicating cellulose type I with the crystallinity of 42%. Meanwhile, the FTIR spectra prove that individual CNF was successfully isolated due to the removal of non-cellulosic constituents. This result verifies that amorphous portions such as lignin and hemicellulose were completely removed. CNFs with long entangled network fibrils were successfully extracted from SCB through the combination of alkaline treatment and mild acid hydrolysis assisted with ultrasonication. The CNFs are expected to have high strength and aspect ratio that can be used as reinforced material in manufacturing nanocomposites.

This paper presents a practical optimum design solution of prismatic simply supported prestressed concrete girders that are subjected to uniformly distributed static loads. While assuming linear elastic behaviour and employing working stresses method, the optimum values of two design variables, namely the cross-sectional dimensions and the prestressing force, are formulated as a nonlinear optimization model. Optimum values of the design variables are computed to satisfy either a minimum weight or a minimum cost objective function. To solve the nonlinear programming models, a program named Non-Linear Programming Prestressed Concrete Optimizer (NLPRECO) was coded in MATLAB® programming environment. Some illustrative design problems were solved using NLPRECO and their results are demonstrated herein. Sensitivity analysis of the optimized design variables, to variations in design parameters, was also investigated and the results are presented. Results show substantial improvement over the regular un-optimized solutions and moderate improvement over a linear programming optimization solutions.

Nanoindentation derived mechanical properties and strain rate sensitivity assessment of a set of stir cast metallic reinforced Aluminium-based composites, with an antecedence of anomalous stress oscillations and strain rate insensitivity during hot compression, was investigated in this study. For the evaluation, Al6063 based composites reinforced with 6 wt% CuZnAl, steel, nickel, and SiC particles were subjected to nanoindentation, and their strain rate sensitivity was assessed using strain rate jump test. The results show that the AMCs reinforced with the metallic particles, presented better mechanical properties than those reinforced with SiC. The CuZnAl reinforced AMC had the best hardness (1.25 ± 0.25 GPa) and elastic modulus (∼83GPa), which is opined to be on account of thermoelastic contributions to the basic strengthening mechanisms. The large scatter observed in the mechanical response of the AMCs is largely due to the inhomogeneous particle distribution. The higher indentation resistance with an increase in strain rate, coupled with the absence of displacement bursts, indicated that the composites largely exhibit positive strain rate sensitivity.

The job sequencing and tool switching (SSP) is a well-known combinatorial optimization problem that aims to minimize the number of tool switches. The problem mainly arises in a flexible manufacturing system, in which machines can be configured with various tools to process different jobs and tool switches will correspond to a reduction of productivity. While the general studies assume uniform setup time for tool switching, applications on the industries indicate that the setup time of a tool might depend on the previously installed tool of the same slot. Therefore, this article proposes two integer linear programming models for the sequence-dependent SSP, namely the five-index formulation and the multicommodity flow formulation. Experimental tests are executed to compare the sequence-dependent SSP with the uniform SSP and the results show the effectiveness of multicommodity flow formulation. Finally, several managerial discussions are derived from the results.

Due to rapid movement of rural population to new regions and countries in order to find work and for better living conditions, population growth and economic development, there is gradual increase in production of waste and demand of electricity worldwide. According to World Bank statistics, the global Municipal Solid Waste generated was 1.3 billion tons in year 2012 and this is expected to increase above 2.2 billion tons per year by 2025. Due to lack of sites for waste disposal, it has become a serious environmental as well as health issue. Now various methods have been adopted for waste disposal. Among this, energy accessed from municipal solid waste is the most common practice adopted by developing countries. In addition, Waste to Energy and Energy from Waste technologies are used which include thermal and biological technologies. Gasification, pyrolysis and incineration are thermal technologies used in conversion of waste to energy. During these processes, syngas is produced which is used in combustion engine or turbines to generate electricity. Apart from this, biomethanation is also used in which biogas is produced. In this review article, we have discussed all the environmental and green methods used for the generation of energy from Municipal Solid Waste their advantages and drawbacks.

This study addresses performances and behaviors of the multi-cross-section HAWT blade design with and without fences. The FX66-S-196 V, FX63-137 S and SG6043, supercritical airfoils were used and distributed along the blade radius; further, the NACA4412 single-cross-section HAWT blade having the same dimensions was used to compare the behaviors and overall performances of all the blades. Analyses were then performed numerically using blade elements momentum BEM theory with a self-code (F.90) and CFD as well as experimentally with three multi-cross-section blades designed using SOLIDWORKS and 3D- printed with polylactic acid. the multi-cross-section HAWT blades show good performance compared with the single- cross-section blade, with an approximately 8% increase in power coefficient, i.e., 40 W, for a miniature wind turbine (127 cm diameter 500 W output power) and greater improvements for wind turbines with large diameters. The fences were designed using boundary layer theory and installed on multi-cross-section blades in experimentally determined positions. The fences showed high performance, with a 16% increase in total power coefficient and high flutter stability.

Reports show that 40% of global carbon emissions come from energy consumed in buildings, so organizations around the world continuously seek ways to reduce their buildings energy consumption. Research identifies three main approaches; Retrofitting, the use of Low Carbon Buildings (LCB), and implementing Energy Management Systems (EMS). However, other factors could affect the success of these approaches; climate and local weather, building types, social acceptance, and implementation. This paper reviews and evaluates 50 reports on these implementations, and uses that evaluation to identify the most effective approach to reduce buildings carbon footprint. In this evaluation, authors used the reported success rate (in reducing carbon footprint) as key parameter, they then cross-checked this with origin of reports (country, climate region), building type, and implementation thoroughness. This allowed the authors to identify not only the best approach, but also understand the impact of these other factors on the reported success rate. Retrofitting was implemented the most (58%) but with varying success (2% to 49% reductions), this variation is attributed to the current state of the buildings and the level/method of retrofitting applied. LCB showed the highest reductions as energy saving measures were preplanned before building construction, this however limits LCB to new and planned buildings. Even though EMS showed results comparable to Retrofitting and required a fraction of the costs/effort, only 14% implemented it, this is an indication of the level of social awareness in the region on the need to reduce carbon footprint and its impact on the world’s climate.

The purpose of this study was to determine the strength of hollow concrete block masonry walls, beams, and columns, and compare their values with brick masonry walls and ordinary reinforced concrete beams and columns. The specimens for the hollow concrete block and brick masonry walls were prepared and tested for compressive and flexural strengths as well as horizontal and diagonal shear strengths. Moreover, two hollow concrete blocks and two ordinary reinforced concrete beams were designed to experience flexural and shear failure and loaded under a two-point bending load. Meanwhile, a hollow concrete block and an ordinary reinforced concrete column were also constructed and subjected to centric axial loads until they collapsed. The results showed the hollow concrete block masonry walls have greater strength than those made with bricks while both flexural and shear capacity as well as the flexural ductility of reinforced hollow concrete block beams were higher than ordinary reinforced concrete beams. Meanwhile, the centric compressive axial strength of the reinforced hollow concrete block column was smaller due to the inefficient bond it has with the infilled concrete which leads to their separation under the compressive axial load.

Initial wettability of rock surfaces plays a crucial role in displacement efficiency during core flooding experiments. In this study, linear alkylbenzene sulfonic acid (LABSA) and silica nanoparticles (NPs) were utilized as enhanced oil recovery (EOR) agents to improve oil recovery from carbonate rock samples. Prior to the core flooding experiments, effects of the presence of LABSA and SiO2 NPs on oil-water interfacial tension (IFT), wettability alteration, and surfactant adsorption on the rock surfaces were evaluated. The results of IFT/contact angle measurements showed that by adding 0.03 wt% LABSA, the IFT, and contact angle reduced from the initial values of 36.9 mN/m and 115.6° ± 0.2° to 8.3 mN/m and 100.3° ± 0.4°, respectively. Furthermore, incorporating SiO2 NPs (0.1 wt %) into the system causes a further decrease in IFT value (dropped to 2.2 mN/m), along with a substantial reduction in contact angle (final contact angle after 6 h soaking into the solution was measured as 64.8° ± 0.3°). In addition, surfactant loss due to the adsorption on the rock surfaces decreased up to 35% in the presence of SiO2 NPs (0.1 wt %). Moreover, various core flooding scenarios in carbonate plugs with different initial wettability conditions were conducted, and the performance of the EOR agents in enhancing oil recovery from oil-wet and water-wet core samples in the secondary and tertiary mode of flooding was evaluated. The outcomes revealed that the injection of a combination of chemicals, containing LABSA (0.03 wt %) and SiO2 (0.1 wt %) in the secondary mode leads to the highest ultimate oil recovery from sister carbonate core samples.

Gum Ghatti (Anogeissus latifolia) is being widely used as an emulsifier, thickener, stabilizer in food, pharmaceutical, and allied industries due to its shelf life, tolerance of heat, and pH stability. Considering the oil & gas industry application, it is ideal for a hydraulic fracturing fluid additive as a direct replacement for Guar Gum. Basically, unlike Guar Gum, it contains less residual hull and it is suitable for low permeability unconventional reservoir; mainly shale gas reservoir, where permeability counts trivial in amount. The polymer of Ghatti aid exceptional rheological properties and help to produce higher molecular weight polymer; which has excellent proppant carrying capacity and fracture propagation. In this paper, the experimental study has been carried out in two different phases. This was achieved through optimization and characterization of hydraulic fracturing fluid which was embedded with gum matrices. In Phase-I, the study was carried out by using Response Surface Methodology (RSM). Wherein, the relation between several explanatory and response variables have been measured. In Phase-II, the characterization was done by using a Scanning Electron Microscope (SEM), Differential Scanning Calorimeter (DSC), Thermo-Gravimetric Analysis (TGA) and also, Fourier-Transform Infrared Spectroscopy (FT-IR). This experimental study will potentially benefit for development of a new hydraulic fracturing fluid. Where Gum Ghatti observed as a satisfactory alternative agent for Guar Gum.

Oil and gas industry continues to the increasing demand of more cost-effective well design and operations. Thus, team successfully eliminated intermediate casing string from the design thereby achieving not only a 33% reduction in dry hole cost/meter, but also delivering wells and producing oil 25% faster than before. Removing an intermediate casing string resulted in a longer open hole (more than 2000 mMD) which by default created new challenges which had to be dealt with and solved without compromising the targeted cost saving. The challenges can be summarized as follow: • Combining loss of circulation zone with unstable shale formations in one section. • PPFG uncertainties. • Bit selection and design optimization. • BHA selection and drive optimization. • Running wireline logging through a long open hole. • Running casing and having good quality cement. • Hole cleaning and displacement efficiency when changing mud systems. • Proper contingencies in place to meet the required completion strategy. Risk assessment, feasibility studies, workshops, and co-operation among all involved personnel has been conducted to ensure that this design optimization would result in positive outcome. Since the first implementation in 2019, more than 17 wells have been successfully delivered and completed in Best in Class performance based on latest update of Rushmore data tracking. The longest open hole section of 2790 m measured depth (MD) with total depth (TD) of 3910 mMD has been achieved generating above 800 Kusd saving per well, thus setting new benchmarks for the field and opening up new opportunities for the future. All this ensure Process Safety and compliance with Well Delivery process. This paper not only describes how two string design was successfully engineered and executed but also serves as a guide for selecting proper candidates for this design and an operational guide for two section wells design to ensure that these challenging long open hole will be successfully drilled while minimizing risks.

Meta-analysis is a statistical analysis of the data obtained from multiple studies and provides a quantitative synthesis of research results. It can be a key tool for facilitating rapid progress in aquaculture by quantifying what is known and identifying what is not yet known. However, due to the complexity of the environment and problems associated with the use of model in aquaculture, it remain few guidelines for the design, implementation or interpretation of meta-analysis in the field of aquaculture. Here, we first briefly reviewed the history of meta-analysis, then summarized the applications of meta-analysis in terms of major procedures, standards, and methods. Next, we critically reviewed the results of meta-analysis studies in the production chain of aquaculture and identified the potentials for improving yield in both quantity and quality. Overall, there is a large room for improving yield along the production chain. Large contributions can be found in breeding, feed, and farm management. For example, improving breeding can increase yield by 5.6% to 49%, depending on fish species and type of improvements. This study revealed large potentials for improving yield in the production chain of aquaculture and summarized the application of meta-analysis in aquaculture. Some recommendations of standardizing and improving meta-analysis in aquaculture were proposed.

In the present paper, a neural network (NN) is proposed for detecting the human-manipulator collisions. Because of that purpose, three types of NNs are designed and trained named as; multilayer feedforward, cascaded forward, and recurrent NNs. The NN is designed based on the joints’ dynamics of the manipulator. In addition, the NN is trained using a dataset with and without the collisions using the algorithm of Levenberg-Marquardt to detect the collisions happened with the manipulator. During the design of the NN, only the intrinsic joint position sensor of the robot is used which enable the proposed method to be applied to any robot. The three designed neural networks are compared quantitatively and qualitatively to each other. Furthermore, the proposed method was evaluated with the KUKA LWR manipulator using one joint motion. The results of the designed systems achieve high effectiveness in detecting the collisions between human and robot.

A hybrid enhanced oil recovery (EOR) method by combining low salinity water (LSW) and low salinity surfactant (LSS) flooding techniques was designed. Different experiments were done to screen the Caspian seawater (SW) with altered ionic composition and surfactant, for the optimized performance in Kazakhstani carbonate oil fields. Changing to a more water-wet state and creating the middle phase were studied as the main criteria to select the best-engineered brine and anionic surfactant. The largest alteration towards the water-wet condition was recorded at 10 times dilution of the SW with 3- and 6- times spiked calcium and sulfate ions, respectively (10xSW-6SO4, Mg, 3Ca). This combination of anionic surfactants with carbonate formations is considered as a new approach in hybrid EOR methods. Among the anionic surfactants screened, Soloterra-113H (Alkyl Benzenesulfonic acid) showed the best solubilization ratio, aqueous stability, and Winsor type 3 microemulsions. The wettability alteration by the combination of optimized brine and screened surfactant was greater compared to the standalone LSW, which was confirmed by the 10° difference in contact angle measurement. The microemulsion phase constituted nearly 40% of the total height of the oil/brine column by the hybrid method. The recovery factor after injecting formation water was 52%, and it increased to 61% after optimized LSW injection. After switching to the engineered brine/surfactant, the recovery factor reached 70%, which proves the effectiveness of the hybrid method. The proposed combined method works better than either standalone EOR method due to the higher alteration in capillary number by changing wettability and reducing IFT, which leads to higher oil recovery.

A discontinuous conduction mode (DCM) high frequency high step up SEPIC-based converter with extended ZVS range is presented in this paper. With the incorporation of some components on conventional SEPIC, the proposed converter achieves better performances such as high voltage gain, low voltage stress and zero voltage switching (ZVS). The additional components form a resonant cell which enables the switches to work in ZVS and switching loss is reduced accordingly. In order to achieve ZVS, the converter is designed to work in DCM. Due to inclusion of the resonance stage, traditional PWM or PFM control method is unable to regulate the output characteristics and maintain ZVS of the power switches at the same time. Therefore, a hybrid control method is proposed in this paper to guarantee ZVS within a specific load range. According to this hybrid control method, the ZVS range is extended effectively. GaN switches and planar magnetic components are also used. Working principles and steady-state analysis are presented in detail. A 1MHz 36W prototype with 10 voltage gain has been designed to demonstrate theoretical analysis. Efficiency obtained is up to 91.8% at full load. Experimental results show good agreement with theoretical analysis.

Drilling muds play an important role in drilling and production operations so that the degree of success in such operations is determined by the proper design of these fluids. To optimize drilling operations and avoid excessive expenditure, it is essential to prepare a drilling mud that is both cheap and efficient. Fluid additives are typically used in drilling systems to improve these fluids' capabilities in terms of hole cleaning capacity, filtration control, viscosity, yield point, heat transfer, etc. However, environmental concerns, cost of production, and availability are always considered challenging factors. This study introduces an eco-friendly herbal fiber in powder and regular forms as a potential alternative to other chemical additives. To do so, Alyssum homolocarpum seed mucilage was added with different concentrations to the water-based drilling muds, and its rheological behavior, filtration control, and the induced formation damage were examined and the optimum concentration was introduced. The results of this study revealed the advantages of the drilling muds formulated with Alyssum in terms of filtration control, rheology, formation damage, and greenness.

A mechanistic model has been applied for the prediction of corrosion rate in multiphase (water–oil-gas) flow regimes. This is due to inadequacies of existing models to adequately address a wide variety of corrosion dependent parameters with special emphasis on multiphase flow parameters. This model takes into account; water cut, volumetric phase fraction of oil and gas, temperature, pressure, other data collected relating to the pipe age, sand particle deposit, CO2 partial pressure, flow velocity, pH, chloride contents, mass transfer coefficients, and hydrogen sulfide. The applied model results show well above 91 percent prediction accuracy, while the prediction error ranges between 0.022 and 0.045 percent. When predicted results compared actual value (experimental data) with DeWaard and Milliams’ model; used in the oil and gas industries, it showed good agreement. It is seen that the resulting model produced an R2 value of 0.91 in comparison to 0.53, the value for Dewaard and Milliams’. It is obvious from numerical simulation that the multiphase flow parameters have major effects on the entire rate of corrosion of oil and gas multiphase flow pipelines. Finally, this research concluded by showing the developed model performance and comparison was made with numerical results. It is expected that the outcome of this research will be of significant help for the strengthening of the application of mechanistic models for predicting corrosion rate. This model will be useful for oil and gas industries worldwide for accurate prediction of corrosion rate.

Foam diversion acidizing can effectively solve the problem of acid distribution with severe heterogeneity between and within layers. Based on the foam diversion principle, the gas trap theory, and volume conservation principle, the foam slug diversion acidizing model was established and solved considering the change of bottomhole temperature and deviation factor of foam. The simulation results show that the change of temperature has a great influence on the diversion effect at the initial stage of injection, but a small influence at the middle and late stage. The effect of temperature on the highly permeable layer is greater than that of temperature on the low permeability layer. The deviation factor of foam is mainly controlled by temperature at the initial stage, and by pressure at the middle and late stage, and the whole process shows a downward trend, which has little influence on the diversion effect. The quasi-skin factor of gas trap is the most important parameter that influences the effect of foam diversion. The water saturation of the low permeability layer rises faster than that of the high permeability layer, and the effect of diversion is obvious. The research results have a strong guiding significance for foam diversion acidizing.