Principal Operation Research Articles

An Electrochemical Aptasensor for the Detection of Freshwater Cyanobacteria.

Aphanizomenon is a genus of cyanobacteria that is filamentous and nitrogen-fixing and inhabits aquatic environments. This genus is known as one of the major producers of cyanotoxins that can affect water quality after the bloom period. In this study, an electrochemical aptasensor is demonstrated using a specific aptamer to detect Aphanizomenon sp. ULC602 for the rapid and sensitive detection of this bacterium. The principal operation of the generated aptasensor is based on the conformational change in the aptamer attached to the electrode surface in the presence of the target bacterium, resulting in a decrease in the current peak, which is measured by square-wave voltammetry (SWV). This aptasensor has a limit of detection (LOD) of OD750~0.3, with an extension to OD750~1.2 and a sensitivity of 456.8 μA·OD750-1·cm-2 without interference from other cyanobacteria. This is the first aptasensor studied that provides rapid detection to monitor the spread of this bacterium quickly in a targeted manner.

Evolution of the supercritical extraction of oilseeds matrix cultivated in brasil: a review

The diversity of oil seeds in in Brazil turns the country into a very important role player in the production of raw material and vegetable plant products such as oil and extracts products. The processes of the extraction of oil with supercritical fluids are potential alternative methods for obtaining vegetable oil as alternative processes for substituting the traditional extraction methods such as manual pressing and extraction with solvent. This method presents advantages such as fast rate of reaction, flexibility of raw material, production efficiency and ecological benefits. This article presents a review covering actual supercritical extraction scenarios of vegetable oil from raw materials found in abundance in Brazil. The review presents a discussion about the influence of the principal operation perimeters on the extraction yield, modes of operation and the proximity with the industrial application, in a huge compilation of works in the period between 2000 - 2016, in other to unravel these indicators and their trends.

SCA-Safe Implementation of Modified SaMAL2R Algorithm in FPGA.

Cryptographic algorithms (RSA, DSA, and ECC) use modular exponentiation as part of the principal operation. However, Non-profiled Side Channel Attacks such as Simple Power Analysis and Differential Power Analysis compromise cryptographic algorithms that use such operation. In this work, we present a modification of a modular exponentiation algorithm implemented in programmable devices, such as the Field Programmable Gate Array, for which we use Virtex-6 and Artix-7 evaluation boards. It is shown that this proposal is not vulnerable to the attacks mentioned previously. Further, a comparison was made with other related works, which use the same family of FPGAs. These comparisons show that this proposal not only defeats physical attack but also reduces the number of resources. For instance, the present work reduces the Look-Up Tables by 3550 and the number of Flip-Flops was decreased by 62,583 compared with other works. Besides, the number of memory blocks used is zero in the present work, in contrast with others that use a large number of blocks. Finally, the clock cycles (latency) are compared in different programmable devices to perform operations.

Optimization-Based High-Frequency Circuit Miniaturization through Implicit and Explicit Constraint Handling: Recent Advances

Miniaturization trends in high-frequency electronics have led to accommodation challenges in the integration of the corresponding components. Size reduction thereof has become a practical necessity. At the same time, the increasing performance demands imposed on electronic systems remain in conflict with component miniaturization. On the practical side, the challenges related to handling design constraints are aggravated by the high cost of system evaluation, normally requiring full-wave electromagnetic (EM) analysis. Some of these issues can be alleviated by implicit constraint handling using the penalty function approach. Yet, its performance depends on the arrangement of the penalty factors, necessitating a costly trial-and-error procedure to identify their optimum setup. A workaround is offered by the recently proposed algorithms with automatic adaptation of the penalty factors using different adjustment schemes. However, these intricate strategies require a continuous problem-dependent adaptation of the penalty function throughout the entire optimization process. Alternative methodologies have been proposed by taking an explicit approach to handle the inequality constraints, along with correction-based control over equality conditions, the combination of which proves to be demonstrably competitive for some miniaturization tasks. Nevertheless, optimization-based miniaturization, whether using implicit or explicit constraint handling, remains a computationally expensive task. A reliable way of reducing the aforementioned costs is the incorporation of multi-resolution EM fidelity models into the miniaturization procedure. Therein, the principal operation is based on the simultaneous monitoring of factors such as quality of the constraint satisfaction, as well as algorithm convergence status. This paper provides an overview of the abovementioned size-reduction algorithms, in which theoretical considerations are illustrated using a number of antenna and microwave circuit case studies.

Review of Ethanol Intoxication Sensing Technologies and Techniques.

The field of alcohol intoxication sensing is over 100 years old, spanning the fields of medicine, chemistry, and computer science, aiming to produce the most effective and accurate methods of quantifying intoxication levels. This review presents the development and the current state of alcohol intoxication quantifying devices and techniques, separated into six major categories: estimates, breath alcohol devices, bodily fluid testing, transdermal sensors, mathematical algorithms, and optical techniques. Each of these categories was researched by analyzing their respective performances and drawbacks. We found that the major developments in monitoring ethanol intoxication levels aim at noninvasive transdermal/optical methods for personal monitoring. Many of the “categories” of ethanol intoxication systems overlap with each other with to a varying extent, hence the division of categories is based only on the principal operation of the techniques described in this review. In summary, the gold-standard method for measuring blood ethanol levels is through gas chromatography. Early estimation methods based on mathematical equations are largely popular in forensic fields. Breath alcohol devices are the most common type of alcohol sensors on the market and are generally implemented in law enforcement. Transdermal sensors vary largely in their sensing methodologies, but they mostly follow the principle of electrical sensing or enzymatic reaction rate. Optical devices and methodologies perform well, with some cases outperforming breath alcohol devices in terms of the precision of measurement. Other estimation algorithms consider multimodal approaches and should not be considered alcohol sensing devices, but rather as prospective measurement of the intoxication influence. This review found 38 unique technologies and techniques for measuring alcohol intoxication, which is testament to the acute interest in the innovation of noninvasive technologies for assessing intoxication.

Development of a portable device for preventing injuries due to a loss of grounding and broken neutral

Any discontinuity in the power cords of electrical devices can lead to electric shock, injury, and even death. This article presents a portable device that, when placed in the proximity of handheld tools, prevents such injuries. The principal operation of this device is based on electric and magnetic field meters and display segment LEDs. When the grounding conductor of a portable tool with a metal enclosure is broken, the electric field around it is increased. In the same way, when the neutral conductor is broken, the magnetic field is increased. The device detects any variations in electric or magnetic fields and displays a warning signal for alert.

Fast Approach for SAR Imaging of Ground-Based Moving Targets Based on Range Azimuth Joint Processing

The synthetic aperture radar (SAR) images of a moving target may be out of focus, given the motions of a non-cooperative target. Doppler ambiguities, including the Doppler center blur and spectrum ambiguity, will easily appear due to the limitations of pulse repetition frequency, which causes difficulty in moving-target imaging. Therefore, a robust fast Doppler ambiguity approach for SAR imaging of a ground-based moving target using range azimuth joint processing (RAJP) is presented. Firstly, the use of RAJP, based on a two-dimensional cross-correlation function and linear range cell migration (LRCM) compensation function, is proposed to simultaneously obtain the first- and second-order phase parameters in the fast-time and azimuth-frequency domains. Then, a corresponding azimuth reference function is constructed to image the moving target. Additionally, a principal component analysis-based operation is introduced to solve the mismatch with the LRCM compensation function. The couplings between the range and azimuth and between the first- and second-order parameters can be simultaneously decoupled by the proposed RAJP operation, which simplifies the processing steps. The developed approach can simultaneously obtain the first- and second-order parameters in the fast-time and azimuth-frequency domains, which avoids the propagation error of parameter estimation caused by the stepwise processing operation. The proposed method is relatively fast, given the need for fewer processing steps. The presented approach is robust in terms of Doppler ambiguity and handles the blind speed sidelobe well. In this study, simulated and real data are processed to verify the proposed approach.

A frequency divider using interacting self‐sustained pulses in a tunnel‐diode‐oscillator lattice

SummaryAn effective method for frequency division, which uses interacting self‐sustained solitary waves propagating in a one‐dimensional tunnel‐diode oscillator lattice, is discussed. When two pulses are input successively, it is found that there is a threshold separation below which the following pulse is significantly attenuated to disappear on the way, which only slightly influences the leading pulse. This phenomenon results in an efficient frequency divider with a high division ratio, which requires a relatively small number of lattice cells. In this study, we illustrate the fundamental dynamics of the self‐sustained pulse interactions and principal operation of frequency division with several experimental validations.

Multiscale Dual-Branch Residual Spectral–Spatial Network With Attention for Hyperspectral Image Classification

The development of remote sensing images in recent years has made it possible to identify materials in inaccessible environments and study natural materials on a large scale. But hyperspectral images (HSIs) are a rich source of information with their unique features in various applications. However, several problems reduce the accuracy of HSI classification; for example, the extracted features are not effective, noise, the correlation of bands, and most importantly, the limited labeled samples. To improve accuracy in the case of limited training samples, we propose a multiscale dual-branch residual spectral–spatial network with attention to the HSI classification model named MDBRSSN in this article. First, due to the correlation and redundancy between HSI bands, a principal component analysis operation is applied to preprocess the raw HSI data. Then, in MDBRSSN, a dual-branch structure is designed to extract the useful spectral–spatial features of HSI. The advanced feature, multiscale abstract information extracted by the convolution neural network, is applied to image processing, which can improve complex hyperspectral data classification accuracy. In addition, the attention mechanisms applied separately to each branch enable MDBRSSN to optimize and refine the extracted feature maps. Such an MDBRSSN framework can learn and fuse deeper hierarchical spectral–spatial features with fewer training samples. The purpose of designing the MDBRSSN model is to have high classification accuracy compared to state-of-the-art methods when the training samples are limited, which is proved by the results of the experiments in this article on four datasets. In Salinas, Pavia University, Indian Pines, and Houston 2013, the proposed model obtained 99.64%, 98.93%, 98.17%, and 96.57% overall accuracy using only 1%, 1%, 5%, and 5% of labeled data for training, respectively, which are much better compared to the state-of-the-art methods.

On the Development of a Simple and Portable Ground-Based Infrared Imaging System for Lunar and Atmospheric Studies

A small, portable, infrared (wavelength of 7 - 14 μm) system has been designed and developed to study the thermal behavior of the lunar surface and for thermal remote sensing applications. The principal operation of the system depends on collecting large amounts of infrared light, using a modified Newtonian telescope. The light from the object is reflected by the primary mirror and the secondary mirror. This collected light is then focused into a thermal camera by using an intermediate germanium lens as a field lens to provide a real optical image on the camera sensor. Several observations have been obtained out using the developed system, and eliciting some interesting results. These include lunar observations during different phases and during partial lunar eclipse. The thermal behavior of the lunar surface was identified, proving the system’s functionality and performance. The developed system is, also, particularly suitable tool for outreach programs and students projects which can possibly offer useful learning and exploration opportunities for students in different applications. In this paper, a brief description about the developed system is provided. Some of the obtained results are illustrated. The future applications and improvements to the designed system are also summarized.

Partial cycle operation of latent heat storage with finned tubes

This work examines a high temperature latent heat storage system, which could find use in future concentrated solar power and other combined heat and power plants. In contrast to lab-based fully charged or totally discharged states, partial load states will be the principal operation states in real-world applications. Hence, a closer look on the partial load states and the effective power rates are worthwhile for a successful implementation of this storage type. A vertical finned shell and tube heat exchanger pipe with a combination of transversal and longitudinal fins is applied. Sodium nitrate with a melting temperature of 306°C is used as phase change material and thermal oil serves as heat transfer fluid. Temperatures in the storage and the heat transfer fluid as well as the mass flow are measured for data analysis. The state of charge formulation is based on an enthalpy distribution function, where the latent heat of fusion is spread over a specific temperature range.The data show consistently high power rates for all partial load cycles at any state of charge. The mean power rate for charging is 6.78kW with an 95.45% confidence interval of ±1.14kW for all cycles. The discharging power rate is −5.72kW with a 95.45% confidence interval of ±1.36kW for all cycles. The lowest power rate is measured for the full cycle at the end of charging/discharging. It is caused by a narrow volume, which is not penetrated by fins, near the perimeter of the cylindrical heat exchanger. The state of charge formulation correlates with the storage capacity and enables state of charge based cycling. With the energy balance of the storage, the data validity is proven and further storage parameters are determined. The energy density is as high as 110kWhm−3 and a power rate of 2.28kWm−1 for the finned tube is confirmed. These values are highly promising for further development and application of latent heat storage systems.

Wiped film evaporators: Segmental assessment of wetting behavior and heat transfer performance

An analysis of different operating points during the evaporation of a subcooled feed in a wiped film evaporator (WFE) allows a conceptual segmental assessment, distinction and quantification of various wetting behaviors and heat transfer situations during the liquid film flow. In detail, single-phase heating, evaporation from a fully covered surface and evaporation from a partly covered surface may be distinguished. For each section the wetting situation is extracted. This knowledge is essential for operating wiped film evaporators within a suitable and appropriate range to prevent e.g. product damage. The experiments were conducted at a stainless steel and steam-heated wiped film evaporator with a spring-loaded, inclined comb wiper system and monoethylene glycole as evaporation fluid. Process pressure, wiper type and rotational velocity were kept constant. Variations of feed rate and driving temperature difference mark out the characteristic operating points. In case of sufficient wetting of the evaporation surface, overall heat transfer coefficients of 1800 W/(m²·K) are reached. By decreasing feed rate and assessing the achieved distillate rate minimum sump loads can be derived for a given driving temperature difference. This quantifies the position of film break-up leading to a partly covered heat transfer surface. Active heat transfer areas are extracted from the experimental data and quantified to get a more precise view on suitable process conditions of WFE and its principal operation.

Soft-Switching Bridgeless Buck–Boost PFC Converter Using Single Magnetic Core

In this article, a new bridgeless single-phase buck-boost power factor correction (PFC) converter with one magnetic core is introduced. The proposed converter is designed to operate in discontinuous capacitor voltage mode (DCVM) to achieve low total harmonic distortion (THD) and continuous input current with a simple structure. The DCVM operation gives additional advantages, such as inherent PFC, low turn-off losses, and reduced complexity of the control circuitry. Unlike the buck converter, the proposed converter eliminates the dead angle of input current without adding any extra circuits. Also, by eliminating two input diodes in power flowing path, the efficiency is further improved. Due to achieved almost zero current switching at the turn-on and almost zero voltage switching at the turn-off, the switching losses are eliminated. In this article, theoretical analysis and principal operation of the converter are discussed. An experimental prototype is implemented to verify the performance of the proposed converter. Experimental results are presented for a 120-W prototype at 110-V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> input and 48-V output.

A SPWM Controlled Input in Dual Buck DC-DC Converter – Full Bridge for Single-Phase Five-Level Inverter

The inverter is very important to be implemented on a power plant system, the principal operation of inverter is a power conversion from DC to AC output. A five-level inverter produces a high-quality total harmonic distortion output side. This paper presents a single-phase five-level inverter using a sinusoidal pulse width modulation (SPWM) controlled in dual buck DC-DC converter and full bridge inverter. The proposed topology is a hybrid converter: dual buck DC-DC converters to generate SPWM voltage level with high frequency and full bridge inverter to generate polarity. This method is very effective to predict the high frequency power semiconductor in dual buck DC-DC converters. The other side the full bridge inverter just need a low frequency. By this method, the gating signals for power semiconductor switches are generated by employing simple pulse width modulation. The fist verification of this topology is by simulation using PSIM software. Finally, a microcontroller dsPIC30F4012 is used in laboratory experiment for the last verification.

Sustained Total All-Region (STAR) Perfusion for Norwood Reconstruction

The acute phase of recovery following the Norwood procedure can be complicated by considerable instability due in part to bleeding, acute kidney injury, systemic inflammatory response, and low cardiac function. The traditional conduct of cardiopulmonary bypass with cooling, re-warming, myocardial ischemia, and upper or lower body ischemia likely exacerbates these problems. Total body perfusion during Norwood reconstruction, without significant cooling or ischemic time to any organs, may improve postoperative recovery by reducing coagulopathy and end-organ injury. Here, we introduce a novel technique for sustained total all-region perfusion of the heart, upper body, and lower body throughout the Norwood operation.

Revision thoracic slide tracheoplasty: Outcomes following unsuccessful tracheal reconstruction.

Over the past decade, thoracic slide tracheoplasty (TST) has become the principal operation in the management of congenital tracheal stenosis. The purpose of this report was to describe our experience with revision TST following unsuccessful prior tracheal reconstruction. Retrospective analysis at an academic children's hospital. Patients undergoing TST on cardiopulmonary bypass between January 2005 and May 2014 were reviewed. Patients with a history of prior airway surgery were extracted for further analysis. Preoperative patient variables and postoperative outcomes were evaluated and compared between patients undergoing revision slide tracheoplasty (RTST) and a control group of 26 matched patients undergoing primary surgery TST. Twenty-six revision patients (25 referrals, one primary patient) of 162 patients reviewed over the study period met inclusion criteria. Twenty-three patients had a history of complete tracheal rings, and three patients had cartilaginous deficiency. A total of 41 airway reconstruction procedures had been performed prior to RTST. When compared to primary TST, patients undergoing RTST required fewer cardiac procedures intraoperatively, and fewer mean ventilator hours (P = .01) postoperatively. There was no significant difference in the median length of stay, requirement of >48 hours ventilation, or postoperative complications between groups. There was one nonsurgical postoperative mortality following RTST. Despite some differences in the postoperative management when compared to nonrevision cases, revision TST can be successfully performed after prior tracheal reconstruction with good postoperative outcomes. 4. Laryngoscope, 128:2181-2186, 2018.

Hardware Implementation of Iterative Method With Adaptive Thresholding for Random Sampling Recovery of Sparse Signals

Sparse recovery methods find extensive applications in various fields such as image and audio processing, wireless communication, and spectral estimation. In this paper, a hardware architecture of iterative method with adaptive thresholding (IMAT) is presented to recover a sparse signal from its random samples. To demonstrate the effectiveness of IMAT, a comparison is performed between the IMAT algorithm and the compressive sensing recovery method, orthogonal matching pursuit, in terms of complexity and reconstruction quality. In the context of image reconstruction, as a practical case, simulation results show the advantages of IMAT in improving the performance of the signal reconstruction via peak signal-to-noise ratio and structural similarity index metrics. Since IMAT employs discrete transform as a principal operation in each iteration, using fast or fast approximate algorithms allows more efficient implementation. In this paper, two multiplication-free transforms, Walsh–Hadamard transform (WHT) and approximate discrete cosine transform (ADCT), are used to reduce computational complexity of IMAT implementation. The IMAT recovery algorithm is implemented on Virtex6 FPGA using two above transforms, and the results are compared with respect to the hardware resource utilization, power consumption, and recovery time. The results demonstrate that using WHT for IMAT implementation is more efficient than using ADCT in terms of hardware resources. Also, the comparison implies that the performance of the hardware implementation is very close to its floating point simulated counterpart. For a block size of $32 \times 32$ , the IMAT implementation using WHT provides the reconstruction time of $185~\mu \text{s}$ and the dynamic power of 123 mW.

336 Civilian Penetrating Craniocerebral Gunshot Injuries

Abstract INTRODUCTION Civillian cranial gunshot wounds (GSWs) remain a frequently lethal and highly morbid injury uncommon to many civilian trauma centers. The vast majority of these patients die prior to reaching medical care. Of those who do survive their initial injury, recent series have shown that over 50% will succumb to their injuries or in-the-hospital complications. Furthermore, experience from wartime theaters has taught us that these patients are vulnerable to a multitude of complications (i.e. CSF leak, wound breakdown, hydrocephalus, vascular injury). Thus, the need and potential for improvement in care and understanding of these patients is large. Here, we present our institution's series of cranial GSWs with an emphasis on detailing our complications. METHODS We retrospectively performed a chart review from 2015–2017. RESULTS &gt;We identified 9 patients that underwent operative intervention in the form of decompressive craniectomy following a craniocerebral gunshot injury at a level 1 trauma center in Washington, D.C. The average age of patients was 31 years (3 females, 6 males) and time to operative intervention from initial presentation was less than 4 hours in 7 out of 9 patients and less than 12 hours in all patients. All patients underwent further operation for a multitude of reasons of which wound breakdown and CSF leak were the most common. These complications extended the hospital initial hospitalization for the majority of patients beyond 2 weeks and were invariably the cause of readmission of these patients. CONCLUSION Not only is aggressive and early intervention critical in caring for patients with cranial GSWs, but also it is important to be vigilant in looking for and preventing further secondary injury from subsequent complications such as wound infections/breakdown, CSF leaks, hydrocephalus and vasospasm. These almost inevitable complications must be anticipated in the treatment planning from the principal operation.

Optimization of the Microwave Properties of the Kinetic-Inductance Bolometer (KIBO)

Silicon nitride membrane based cryogenic bolometers exhibit high sensitivity and enable ultra-sensitive detector applications. Multi-pixel instruments were already introduced as devices for submillimeter-wave imaging. Nevertheless, the numbers of pixels are limited by the readout process which is typically a time-division multiplexing or code-division multiplexing technique. To overcome this challenge, a replacement of the transition-edge sensor as thermometer by a lumped-element resonance circuit seems to be a promising solution. Therefore, one can benefit from the intrinsic capability of frequency-division multiplexing that allows the readout of large detector arrays simultaneously and in real-time. The number of pixels is then limited by the available readout bandwidth and the quality factors of each individual resonance circuit. We successfully demonstrated, based on our feasibility study, the principal operation of such a device, what we call kinetic-inductance bolometer (KIBO). But the overall performance of the achievable noise-equivalent power (NEP) was limited by implementation and operation temperature of KIBO. Therefore, improved KIBO designs were developed and fabricated with niobium thin-film technology. In this paper, we describe the improvement procedure and estimate the expected NEP value.

Revisit of Sin (n = 21–29) Clusters by Ab Initio Global Search

Using our improved genetic algorithm combined with density functional theory calculations, we perform unbiased global search for the most stable structures of Sin clusters with n = 21–29. A new principal direction crossover operation is introduced to search the prolate structures on the potential energy surface. We confirmed previous results for most sized Sin clusters and find more stable structure at n = 23 and 26. In particular, we find a new endohedral cage structure at Si23, which is 0.4 eV lower in energy than previously reported prolate structure and exhibit a distinct peak on the second order difference of total cluster energy. We discuss the competition between prolate and spherical motifs in the medium-sized Sin clusters in light of binding energy and HOMO–LUMO gap. The transition of structural motif from prolate to near spherical in Sin clusters occurs at n = 26. The outer cages are composed of pentagon, hexagon, quadrangle and heptagon, with one to three interior atoms filled inside the cage. These results establish a more complete picture for the structural evolution of the medium-sized silicon clusters. Average bond lengths and Mayer bond order are also discussed.