bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Heat and Power System For a Carbon Black Manufacturer: System Selection and Speci fication
Authors: Kozman Theodore A. , DaCosta Jesús , Lee Jim
Published: April 2022

This research investigates the use of combined heat and power(CHP) system for a carbon black manufacturer to reduce the energycost. The analysis of the facility energy consumption shows that a steam-turbine-driven CHP system could provide for the electric needs of thecompany. The recuperation of the heat from the low pressure steam canbe injected into the reactor to provide heat, which can substitute forsome of the heat from the natural gas. For the electric needs, our studyindicates that the facility can bene fit from generating a baseline loadto ensure that no excess electricity is produced. The suggested solutionin this research is to be considered as a preliminary solution. Furtherstudies are necessary to be carried out by professional CHP developersto yield more accurate speci fications and costs.
The Past, Present, and Future of Phosphoric Acid Fuel Cells Operating on Anaerobic Digester Gas
Authors: McCord Mr. Kent R.
Published: April 2022

With high efficiency, virtually zero emissions, and 24/7 gen-eration capability, fuel cells represent the cleanest means of generatingcontinuous on-site electrical power of any available technology. Whenfueled by the waste gases (anaerobic digester gas, ADG) from anaero-bic digestion-based wastewater treatment facilities, stationary fuel cellscan turn an emissions liability into a revenue-generating asset, whilesignificantly reducing emissions of both air pollutants and greenhousegases. ADG fuel cell applications often qualify for sizeable governmentincentive programs given the widespread acceptance of ADG as a re-newable fuel. The PureCell™ fuel cell power system from UTC Powerhas accumulated more than 400,000 hours of operation on ADG at 22installations worldwide. This article will describe the capabilities of thePureCell system operating on both natural gas and ADG, as well as theexperience gained from UTC Power’s fleet. Current and future productofferings will be presented with speci fic emphasis on opportunities forADG applications.
Supply-side Strategy Implications on Demand-side Opportunities
Authors: Austin Stephen B.
Published: April 2022

Major changes in the gas and electric markets have created arange of risk management products to support supply-side planning.The supply-side goal is usually to balance a client’s tolerance for costfluctuations with the lowest possible price. There are many implicationsa supply strategy has on demand-side opportunities. They should beconsidered carefully. This integration of supply and demand-side plan-ning often does not take place because they have been thought of as twoindependent disciplines. They require two separate sets of expertise.Historically, demand-side planning has been a responsibility forengineering and operations while supply-side planning was the domainof purchasing and procurement. The integration of supply and demandis critical to control of your total energy picture. The right hand needsto know what the left hand is doing. There are a number of situationsthat illustrate where an integrated supply and demand-side approach isvitally important.This article will examine two situations as examples. We will showhow your supply-side strategy affects your true energy costs and howthat is different than in the past. We will also show how a supply-sidestrategy gives new triggers for demand-side actions.
Thermodynamic Simulation of A Combined Cycle Power Plant At Part-Load Operation
Authors: Srinivas T. , Gupta A.V.S.S. Kumara Swami , Reddy B.V.
Published: April 2022

A 355 MW combined-cycle power plant has been modeled andsimulated at part loads. Results of a sensitivity analysis of the effect ofhigh pressure (HP) on the combined-cycle performance are presented.The best combination of process parameters of steam leaving the steamgenerator that will give optimum performance of the combined-cyclepower plant were determined at part load operation. Results for theoptimum values of thermal efficiency and power output, together withvalues of the decision variables, are presented. At part loads, the plantdemands lower values of HP pressure to get a suitable dry steam at thesteam turbine exit. The combined cycle gives higher power output withhigh efficiency at full load comparatively at partial loads.
Optimal Cogeneration Technology Selection for Residential and Commercial Buildings
Authors: Serrano Miguel Angel Lozano , Saravia José Ramos
Published: April 2022

The energy requirements for most residential and commercialbuildings show both annual or seasonal, and daily variations. In addi-tion, depending on the electrical rate schedule and location, there canbe time-of-use variation in the prices a customer pays for electricity.Such facts make it harder to select (a) the best-fit equipment for the hostbuilding and (b) the best operating strategy for the selected equipment.This article proposes a mixed integer programming (MILP) model tohelp decide the optimal make up of a prospect cogeneration system asapplied to a residential complex located in Zaragoza, Spain. The modelconsiders the possibility of whether to use or not a set of proposed al-ternative technologies within a previously defined superstructure. Suchsuperstructure is defined through binary variables and takes into ac-count the optimal operation of all feasible combinations of technologiesthroughout a typical meteorological year. The model’s objective functionis to minimize the total annual cost, which includes the cost of investedcapital, subject to technical, economic and legal constraints.
Optimal Location and Sizing of Distributed Generation In a Power Distribution System
Authors: Mohanty Amiya , Modi Pawan Kumar
Published: April 2022

Modern electric power distribution utilities are continuously underpressure for expansion of their networks in order to face the load growthand to properly supply their consumers. To meet these objectives, thereis a need to provide acceptable climate for the entry of distributedresources and innovative operating practices. This article focuses ondetermining the effect of inserting a Distributed Generation (DG) unitin a power distribution system in India. The effect on the system volt-age profile and line losses is evaluated. This has been accomplished bymodeling the connection of a DG unit to different distribution buses andvarying the DG unit size in a 13-bus test feeder. A financial evaluationhas been carried out to examine implementation viability. The resultsshow that the voltage profile is improved, losses are reduced and conse-quently the utility can obtain financial benefits when DG is incorporatedinto the system.
Frequency Control of Microgrid Based on Compressed Air Energy Storage System
Authors: Latha R. , Palanivel S. , Kanakaraj Dr. J.
Published: April 2022

The electrical power system operates under variable load condi-tion, so the load tracking problem will arise which can cause voltageand frequency instabilities. Energy storage devices are able to balancethe fluctuation of power generation and consumption. In this article theuse of Compressed Air Energy Storage (CAES) system for microgrid isproposed. Under variable load conditions, the stored compressed airfrom the CAES system will be utilized to meet the demand. Duringpower generation an excess power is used to compress the air. An airflow controller for CAES is designed to control the air flow from theCAES system, so that the microgrid follows the various load demandsto maintain the stable frequency. The performance of the proposed sys-tem is validated through simulation study for various load conditionsis carried out using MATLAB/Simulink.
Addressing Solar-PV Power Generation: Commercialization Assessment for the US Energy Market
Authors: Yaqub Mahdi , Sarkani Shahram , Mazzuchi Thomas
Published: April 2022

Solar-Photovoltaic (PV) utility power is more expensive to producecompared with conventional sources. Current utility power purchaseagreement policies discourage private investment because far futurecash flow does not add to asset value. This article presents an overviewof a study that assesses the commercialization of PV power generationin the US energy market. Data analysis substantiates that for PV powerto be competitive with conventional power plants, much lower discountrates are required during the first half of the PV utility lifecycle, afterwhich solar PV will have a much lower cost due to a drastic reductionin the cost of capital. Additionally, the levelized cost of energy analysisfor a longer lifecycle indicates that the utility scale solar PV cost gap canbe bridged. Therefore, this article aims to influence policy makers to in-troduce long-term power purchase agreements, taking into account theavoided costs due to the unevaluated quality of long life at anticipatedlow operating costs. Furthermore, simulations reveal that the proposedsolar PV self-financing program may be a viable alternative to the cur-rent government subsidy that lacks an inflow of cash to offset the out-flow of subsidy payments. Finally, we present selective strategies thatcan help drive the commercialization of PV power generation in the USenergy market.
Tidal Energy and Main Resources In the Persian Gulf
Authors: Gorji-Bandpy Mofid , Azimi Mohammadreza , Jouya Mohsen
Published: April 2022

Due to increasing concern over global climate change, manypolicy makers worldwide have accepted the importance of reducinggreenhouse gas emissions, in particular from the electricity industry.Tidal generation has a significant advantage over many other forms ofrenewable generation as it is almost perfectly forecastable over long timehorizons. Thus, incorporating tidal generation into an electricity systemshould be less challenging than other forms of renewable generationwhich are relatively unpredictable. In this article, we discussed aboutthe capacity benefit of tidal generation, especially in Iran.
Effect of Oxygen Enrichment of Intake Air on the Performance and Emission of Single Cylinder CI Engine Fueled with Cardanol Blends
Authors: P. Mr. Dinesha , Mohanan Dr. P.
Published: April 2022

In this study, the effect of intake air enrichment on the performance and emission characteristics of a single-cylinder direct-injection diesel engine fueled with non edible oil namely Cardanol—diesel-methanol blend (B20M10) are investigated. With increase of intake air oxygen concentration, CO and HC decreased while brake thermal efficiency and NOx considerably increased. The maximum Brake Thermal Efficiency of 33.98% is obtained for B20M10 with 7% oxygen enrichment of intake air. Maximum NOx emission 20% is obtained for B20M10 with 7% oxygen enrichment for the full load condition. Decreases of 20% and 14.5% in CO emission are obtained for B20M10, over B20M10 with 7% oxygen enrichment, where as 76.8% and 74% decrease in hydrocarbon emission is obtained over B20M10 without oxygen enrichment.
Optimal Sizing and Siting of Distributed Generators by Exhaustive Search
Authors: H.A Mahmoud Pesaran , Zin Abdullah Asuhaimi Mohd , Khairuddin Azhar , Shariati Omid
Published: April 2022

Dispersed generation generally refers to power generation onthe customer side of a power network. This article demonstrates theimprovement in network parameters which could be achieved by us -ing single and multiple Distributed Generation units in three selectedstandard networks. A reliable multi variable method is used for find -ing optimal installation point and size of distributed generation units.Their sites and sizes are recognized by implementation of a proposedmethod with exhaustive search. Optimization has been applied onnetwork total active and reactive losses together with voltage varia -tion. IEEE 6, 14 and 30 buses standard networks have been selected asstudy cases. The total active and reactive power losses are minimizedwhile voltage profile is improved by installing Distributed Generationunits on recognized optimal points with achieved optimal size.
An integrated Control Approach and Power Management of Stand-alone Hybrid Wind/PV/Battery Power Generation System with Maximum Power Extraction Capability
Authors: N.S. Jayalakshmi , Gaonkar D.N.
Published: April 2022

The production of electricity from renewable energy sources likewind and photovoltaic energy has increased in recent years, due to en -vironmental problems and the shortage of traditional energy sources.In this article we present a detailed mathematical model and a controlscheme for hybrid wind and PV based DG system with battery and max-imum power extraction capability for isolated mode of operation. Thewind power generation system uses wind turbine (WT), a permanentmagnet synchronous generator (PMSG), a three-phase diode rectifierbridge, DC/DC boost converter with maximum power point tracking(MPPT) controller. The PV generation system uses PV array, a boostconverter with maximum power point tracking controller. Both sourcesand battery are connected to common dc bus with a dc link capacitorand supply power to load through PWM voltage source inverter. Theoverall control system consists of MPPT controller for both Wind andPV power system, a bi-directional dc-dc converter controller for batteryenergy storage management and load side inverter controller for volt -age and frequency regulation. Control strategies for individual systemcomponents of the proposed system are designed with a view to achievean acceptable level of voltage and frequency regulation while extract -ing the maximum power from wind and PV system. The performanceof the developed hybrid system is investigated in terms of voltage andfrequency regulation capability under changing wind, solar irradiation and variable load conditions.
Wave Energy Converters and Design Considerations for Gulf of Mexico
Authors: Guiberteau Kelly L. , Lee Jim , Liu Yucheng , Dou Yangqing , Kozman Theodore A.
Published: April 2022

This article presents an investigational study on wave energy con-verters (WECs) and the design considerations for possible implementa -tion in the Gulf of Mexico (GOM). The types of WEC available from themarket are studied first. The design considerations for implementinga WEC in GOM are then evaluated. There are several different typesof devices that can be used in the system design. Each device type hasdifferent attributes that may be helpful or hurtful for the area and waveactivity in the GOM. From the evaluation there is a recommendation ofthe optimal device design conditions, and three device types are recom-mended for further pursuit as design candidates. Six different WECprojects that are currently being developed and most are ready for com-mercial testing are examined. Our study evaluates the usefulness of theWECs for the GOM, and provides design factors of both physical andeconomic scaling. The result of this investigation reveals that while noneof the devices can be installed “as is” in the GOM because of wave poweror geometry requirements, there are some that have the potential to bemodified and scaled down to fit the GOM climate.
Feasibility Analysis Model for Mini Hydropower Plant in Tioman Island, Malaysia
Authors: Nithiyananthan K. , Marimuthu Pratap Nair
Published: April 2022

This study focuses on the technical, theoretical and financialanalysis of a hydro power plant, which is considered as dependable andsustainable among all other forms of renewable energy. Hydropowerenergy is broadly used all over the world, whether in the form of mini-hydro for a single village or a massive dam to serve the entire country.Industrialized countries have utilized their hydro potential extensively.However, in the developing world, particularly in the equatorial zone,hydropower remains an option with considerable potential for satisfy -ing energy needs. The study was conducted using the RETScreen CleanEnergy Project Analysis software. Based on hydrology analysis, thedesign of mini hydro is optimized by considering costing, efficiency, ex -pected operating and capacity factor. In addition, plant design and sizeare evaluated by using capacity factor, NPV and payback period. Fromthe financial analysis, a NPV value of RM3.5 million and payback periodof 10.8 years is obtained for the underlying project.
Palm Oil Mill Effluent (POME): Biogas Power Plant
Authors: Firdaus Nofirman , Prasetyo Bambang Teguh , Sofyan Yoesbar , Siregar Fachruddin
Published: April 2022

Indonesia is the largest palm oil producer in the world. The palm oil mills process fresh fruit bunches (FBB) and produce two main products: Crude palm oil (CPO) and palm kernel oil (PKO). The process generates abundant waste water called palm oil mill effluent (POME). The POME is then converted into biogas through a gasification process. The biogas is used to fuel gas engine and generates electricity. This article presents the technical and economic analysis of a biogas power plant in Indonesia. Also, it analyzes waste heat recovery potential from biogas engine.
Social Acceptance of Renewable Ener9y in Developin9 Countries:Challenges and Opportunities
Authors: Aslani Dr. Alireza , Hosseini Ali , Zolfagharzadeh Dr. Mohammad Mahdi , Sadabadi Ali Asghar , Jafari Hoda
Published: April 2022

Utilization of renewable energy technologies has short-term,middle-term and long term interests. Since the portion of renewableenergies have to increase 10% till 2025, legislating relevant policies forincreasing the portion of these energies is essential. This article reportsstudies about the social acceptance level of renewable energies in aselected developing country by using social acceptance pyramid. First,the identified indicators are weighted based on the circumstances ofrenewable energies. After that, the selected renewable sources, wind,solar, and geothermal, are ranked based on the indicators and analyticalhierarchy process. The research results indicate that wind energy hasthe better social acceptance position than solar and geothermal energies.Finally, some polices are suggested for increasing the acceptance level ofall renewable energies in developing countries.
Analysis and Ranking of Barriers in Development of Solar Power Using Interpretive Structural Modeling Method: Ethiopian Outlook
Authors: Mekonnen Tefera , Bhandari Ramchandra , Ancha Venkata Ramayya , Khan Baseem
Published: April 2022

Ethiopia is quick evolving economy in Sub-Saharan Africa, and its industrialsector is growing faster. However, as a country level there is a significantelectricity shortage. The country needs gigantic increments in capacity tomeet the request of its quickly developing economy and population. Indeedin the event that endeavors are underway for renewable energy expansionin Ethiopia but stills solar oriented energy source are not highly utilizeddue to different problems that ruin its dispersion. On this basis, barriers ofsolar energy implementation in Ethiopia were identified utilizing different literature overview and experts’ view in this investigation. Interpretive Struc-tural Modeling (ISM) technique is adopted to recognize the interrelationshipbetween the distinguished barriers. Matrice d’Impacts Croises-MultipicationApplique’ a Classment (MICMAC) method has too been utilized to sort thebarriers based on dependence power and driving force. The results showedthat four barriers related with economics, environmental and behavioralappear at the upper level in ISM configuration. A policy barrier shows up atthe lowermost of model, and this is considered as the foremost powerful fac-tor. Various solutions for relieving these distinguished barriers have moreoverbeen recommended within the paper. Well understanding of these barrierscan help the concerned stakeholders and policy creators to create proactiveplans and fortification policies to increase the solar powered advancement inEthiopia.
Power Command Optimal Allocation Model of Distributed Energy System Based on Improved Firefly Algorithm
Authors: Xue Xiao , Zheng Yangbing , Lu Chao
Published: April 2022

In order to enhance the power command allocation effect of distributedenergy system, the modified firefly algorithm is established to deal with theoptimal model of the proposed power command allocation. Firstly, the basicfunction and physical structure of power grid system distributed energy sys-tem are analyzed. Secondly, theoretical model of power command allocationmodel distributed energy system is constructed. Thirdly, the improved fireflyalgorithm is established. Finally, a power grid system distributed energysystem with eight units is selected to carry out simulation analysis, resultsillustrate that the model has quickest convergence efficiency, and can obtainoptimal power command allocation effect distributed energy system.
Smart Electricity Meter Prognostics Based on Lithium Battery RUL Prediction
Authors: Chen Ye , Chen Ziyi , Zhu Mengmeng , Liao Yaohua , Luo Fang , Li Xinru
Published: April 2022

Smart Electricity Meters (SEMs) are widely used in distributed generationsystem, and over 67% of its failure are caused by battery low-voltage.Therefore, it is necessary to study the degradation of battery voltage. Thiswork explores the degradation mechanism of lithium battery and proposed touse voltage as degradation index to estimate the health status of the system.Four groups of batteries of the same type and batch are used for the test.The purpose is to use multiple sets of data to train the model parametersand enhance the robustness of the model. The Particle Filtering (PF) basedapproach is used in this study to estimate the degradation state such that theRemaining Useful Life (RUL) can be predicted. An accurate prediction canprovide the proper maintenance/replacement schedule for the SEMs beforethe failure occurs.
Impact of LoRA and 5G on Smart Manufacturing from Automation Perspective
Authors: Kamal Muhammad Ayoub , Alam Muhammad Mansoor , Sajak Aznida binti Abu Bakar , Su’ud Mazliham Mohd
Published: April 2022

The Industrial Internet of Things (IIoT), also known as Industry 4.0, is a forward-thinking industrial era in which numerous developing technologies are combined to produce digital solutions. In industrial enterprises, Industry 4.0 technologies are separated into base and front-end technologies. Cloud computing, IoT, analytics, and big data are all essential technologies. In this article, we evaluate the current landscape of factory automation and the influence of 5G and LoRA communication on smart manufacturing automation, while front-end technologies are split into four categories: smart goods, smart working, smart manufacturing, and smart supply chain. First, we looked at the idea of Industry 4.0, as well as the four front-end dimensions and four basic technological components. Second, we spoke about smart industrial automation and the influence of 5G and LoRA communication. The broad use of front-end technology, of which Smart Manufacturing is a crucial component, is required for Industry 4.0 to succeed. However, the implementation of the foundation technologies is difficult. Current automation standards will serve as a solid foundation for future smart manufacturing systems. The distribution, adoption, and development of relevant morality in a requirement-driven process may result in faster, deeper, and bigger implementation of smart industrial automation.
Lightweight and Secure Authentication Model for Vehicle to Everything (V2X) Communication Based on 5G Networks
Authors: Houmer Meriem , Laqtib Safaa , Eddamiri Siham
Published: April 2022

Integrating the cellular network infrastructure into Intelligent Transport Systems (ITS) received attention from the research community and standards groups. This technology allows the invention and development of new applications, as well as the development of new vehicle mobility solutions and the enhancement of driver mobility in terms of safety, reliability, capacity, and quality. Cellular communications networks such as LTE-V2X and 5G NR, integrated into the Vehicle to Everything (V2X) architecture designed to support vehicular communications and deployed on a large scale, appear in particular to be a relevant solution. They could indeed guarantee reliable geographic distribution and acceptable performance (latency, bandwidth, packet loss). In this context, we propose a secure authentication scheme for 5G-based V2X communication. To achieve security requirements, our approach aims to provide a high degree of security in different vehicular communication (V2V, V2I, V2N) by using lightweight cryptographic algorithms in order to safely receive all keys and messages from RSU, vehicles, and the network. To validate our approach, we use the Automated Validation of Internet Security Protocols and Applications (AVISPA) tool to achieve the security goals, also evaluate the performance according to the operational cost which demonstrates that our model has a less computational cost.
Numerical study of the thermally adaptive emissivity of VO2–polymer nanostructured coatings
Authors: Péralle Cindy , Charrière Renée , Faucheu Jenny
Published: April 2022

The emissivity of an opal photonic crystal loaded with thermochromic

V
O

2

nanoparticles is studied through optical calculations, highlighting the influence of the structure by comparison with a homogenized model. Parameters are first set to maximize the structure influence on material emissivity. Then, a full study of the influence of the

V
O

2

concentration is made to identify, on one hand, cases with the highest structure impact, and on the other hand, interesting cases for applications such as energy-efficient coatings for buildings, satellites, and camouflage applications.
Impact of the optical parametric amplification phase on laser pulse compression
Authors: Musgrave J. , Bromage J.
Published: April 2022

Optical parametric chirped-pulse amplification (OPCPA) is an effective
way to generate ultrashort pulses that has been used extensively for a
variety of applications requiring high peak intensities. Precise
control and measurement of a system’s spectral and spatial phases are
required for Fourier-transform–limited pulse compression and
diffraction-limited focusing. Phase accumulated during optical
parametric amplification (OPA) can degrade the compressibility and
focusability of the pulse, reducing peak intensity. We used analytic
and numerical analysis of OPA to study the influence of crystal
parameters, the wavefront of the pump and signal, and their relative
optical alignment on the accumulated phase. We show that the
accumulated signal phase is largely independent of amplifier
saturation and, with significant local wavefront gradients in the
signal or pump beam, the quality of the compressed pulses can be
degraded. We use first-order expressions for the pump- and
signal-angle sensitivity to evaluate an OPCPA system consisting of a
highly deuterated potassium dihydrogen phosphate amplifier designed to
support bandwidth for 15 fs pulses centered at 920 nm.
Scanning force sensing at micrometer distances from a conductive surface with nanospheres in an optical lattice
Authors: Montoya Cris , Alejandro Eduardo , Eom William , Grass Daniel , Clarisse Nicolas , Witherspoon Apryl , Geraci Andrew A.
Published: April 2022

The center-of-mass motion of optically trapped dielectric nanoparticles in a vacuum is extremely well decoupled from its environment, making a powerful tool for measurements of feeble subattonewton forces. We demonstrate a method to trap and maneuver nanoparticles in an optical standing wave potential formed by retroreflecting a laser beam from a metallic mirror surface. We can reliably position a

∼

170

n
m

diameter silica nanoparticle at distances of a few hundred nanometers to tens of micrometers from the surface of a gold-coated silicon mirror by transferring it from a single-beam tweezer trap into the standing wave potential. We can further measure forces experienced by the particle while scanning the two-dimensional space parallel to the mirror surface, and we find no significant excess force noise in the vicinity of the surface. This method may enable three-dimensional scanning force sensing near surfaces using optically trapped nanoparticles, promising for high-sensitivity scanning force microscopy, tests of the Casimir effect, and tests of the gravitational inverse square law at micrometer scales.
Measurement of differential mode group delay in few-mode fiber with correlation optical time-domain reflectometer
Authors: Jin Linqi , Wang Yong , Zhang Meiling , Sun Yadong , Hu Guijun
Published: April 2022

A measurement system of differential mode group delay (DMGD) in few-mode fiber with correlation optical time-domain reflection was proposed. A photonic lantern used in the system can be utilized for mode separation and selection and can generate six LP modes:

L
P

01

,

L
P

11
a

,

L
P

11
b

,

L
P

21
a

,

L
P

21
b

, and

L
P

02

. The signal reflected by the end of the fiber is correlated with the data sequence sent, which realizes the single-ended measurement of 5 km few-mode fiber DMGD. This method is not destructive for detecting fiber transmission systems and is simple and easy to implement. It can be used for detecting fiber transmission characteristics in the mode-division multiplexing communication system.
Athermal echelle grating and tunable echelle grating demultiplexers using a Mach-Zehnder interferometer launch structure
Authors: Melati Daniele , Xu Dan-Xia , Cheriton Ross , Wang Shurui , Vachon Martin , Schmid Jens H. , Cheben Pavel , Janz Siegfried
Published: April 2022

We present a comparative experimental study of three silicon photonic echelle grating demultiplexers that are integrated with a Mach-Zehnder interferometer (MZI) launch structure. By appropriate choice of the MZI configuration, the temperature induced shift of the demultiplexer channel wavelengths can be suppressed (athermal) or enhanced (super-thermal) or be controlled by an on-chip micro-heater. The latter two configurations allow the channel wavelengths to be actively tuned using lower power than possible by temperature tuning a conventional echelle demultiplexer. In the athermal configuration, the measured channel spectral shift is reduced to less than 10 pm/°C, compared to the 83 pm/°C shift for an unmodified echelle device. In super-thermal operation an enhanced channel temperature tuning rate of 170 pm/°C is achieved. Finally, by modulating the MZI phase with an on-chip heater, the demultiplexer channels can be actively tuned to correct for ambient temperature fluctuations up to 20 °C, using a drive current of less than 20 mA.
Simultaneous determination of the shape and refractive index of a deformed microjet cavity from its resonances
Authors: Moon Songky , Shin Younghoon , Kim Soyun , Park Kyu-Won , An Kyungwon
Published: April 2022

Measuring the boundary shape of a deformed liquid microjet is of great importance for using it as an optical resonator for various applications. However, there have been technical challenges due to transparency and uncertainty in the refractive index of the liquid. In this study, we have developed a spectroscopic technique that enables simultaneous determination of the boundary shape and the refractive index of a liquid deformed microjet. A detailed procedure of the technique based on imposition of one-to-one correspondence between experimentally observed resonances and numerically calculated ones are presented along with the measurement results including the refractive index of ethanol between a wavelength of 550 nm and 670 nm.
Superachromatic polarization modulator for stable and complete polarization measurement over an ultra-wide spectral range
Authors: Gu Honggang , Jiang Hao , Chen Xiuguo , Zhang Chuanwei , Liu Shiyuan
Published: April 2022

The polarization measurement system deals with polarized light-matter interactions, and has been a kind of powerful optical metrology applied in wide fields of physics and material. In this paper, we address several general theoretical aspects related to the system model and optimization for linear polarization systems from a view of the matrix algebra. Based on these theories, we propose a new framework of superachromatic polarization modulator (PM) by combining a linear polarizer and a sequence of parallel linear retarders (LRs) for a typical kind of linear polarization system based on the rotating compensator (RC) principle. In the proposed PM, the LRs are made of quarter-wave plates and as a whole act as the RC. Compared with conventional achromatic/superachromatic composite waveplates, the LR sequence has general axis orientations and is optimized by the condition number of the instrument matrix of the PM, which thereby provide much more flexibility to achieve uniform, stable and complete polarization modulation over ultra-wide spectral range. The intrinsic mechanisms, including the working principle, optimization strategy and in-situ calibration method of the proposed PM, are presented and revealed mathematically by the matrix algebra. Results on several prototypes of the PM demonstrate the validity and capability of the proposed methods for applications in broadband polarization measurement systems. The fabricated PM is further applied to a home-made dual RC Mueller matrix ellipsometer, and the accuracy and precision in the full Mueller matrix measurement are better than 2‰ and 0.6‰ respectively over the ultra-wide spectral range of 200∼1000 nm. Compared with existing techniques, the proposed PM has advantages due to superachromatic performances over ultra-wide spectral ranges, stable and complete modulation of the polarized light, and convenience for adjustment and calibration.
Imaging-photoplethysmography-guided optical microangiography
Authors: He Qinghua , Wang Ruikang K.
Published: April 2022

We report a method to image facial cutaneous microvascular perfusion using wide-field imaging photoplethysmography (iPPG) and handheld swept-source optical coherence tomography (OCT). The iPPG system employs a 16-bit-depth camera to provide a 2D wide-field blood pulsation map that is then used as a positioning guidance for OCT imaging of cutaneous microvasculature. We show the results from iPPG and OCT to demonstrate the ability of guided imaging of cutaneous microvasculature, which is potentially useful for the assessment of skin conditions in dermatology and cosmetology.
Aesthetic judgment of architecture for Chinese observers
Authors: Dai Anbang , Zou Jiajie , Wang Junru , Ding Nai , Fukuda Hiroatsu
Published: April 2022

Architects should consider the aesthetic experience of potential users when designing architectures. Previous studies have shown that subjective aesthetic judgment of architectures is influenced by structure features, and Western observers prefer structures that have curvilinear contours, high ceilings, and open space. The building styles, however, vary across cultures, and it remains unclear whether the preference for contours, ceiling height, and openness exist across cultures. To investigate this issue, this study analyzes the aesthetic judgment of Chinese observers, and the results demonstrate that Chinese observers also prefer high ceilings and open space. Preference for curvilinear contours, however, interacts with ceiling height and openness. Simple effect analysis reveals that Chinese observers prefer curvilinear contours only when the ceiling is low and the space is closed. In sum, these results suggest that preference for high ceilings and open space is robust for Chinese observers, but the preference for curvilinear contours is less reliable.
Determination of human papillomavirus type in archival tissue specimens of invasive cervical cancer using molecular mapping and E6/E7-based polymerase chain reaction
Authors: Sakamoto Jinichi , Saito Mayumi , Zhang Shitai , Takakura Masahiro , Takagi Hiroaki , Sasagawa Toshiyuki
Published: April 2022

In our previous study, an L1-based human papillomavirus (HPV) test using liquid-based cytology revealed that some invasive cervical cancers (ICC) exhibited multiple HPV types or harbored no HPV DNA. Here, molecular mapping of formalin-fixed paraffin-embedded cancer tissue specimens from the same patients were conducted to confirm these observations. Among 377 ICC cases, 73 eligible specimens (9 positive for multiple HPV types, 16 negative for HPV, and 48 positive for a single HPV type from the previous study) were reexamined by manual microdissection of cancer lesions, then subjected to HPV genotyping using the uniplex E6/E7 polymerase-chain-reaction method to detect all high-risk and potentially high-risk HPV types. The HPV typing results were confirmed in 52 of 73 cancer cases; among the 21 remaining cases, 15 were discordant and 6 were partially concordant. In total, 8 of 16 (50%) HPV-negative samples became positive; 6 were positive for HPV16 and 2 were positive for HPV67. Moreover, two samples previously positive for HPV6 and HPV53 were negative for HPV. All nine cancers with multiple HPV types were found to harbor only a single HPV type. In total, 63 cancer tissues exhibited a single HPV type. HPV16 and HPV18 were detected in squamous cell carcinoma (SCC) and adenocarcinoma (ADC). Alpha-5 (HPV82), -6 (HPV56), and -9 (HPV31/52/67) HPV types were detected in SCC, whereas Alpha-7 (HPV59/68) types were detected in ADC and adenosquamous carcinoma (ADSCC). These findings suggested that the different HPV types induced different histological cancers. Furthermore, all SCCs and 10 of 11 usual-type ADCs were positive for high-risk HPV types, supporting the use of HPV screening for the detection of these cancers and associated premalignant lesions. HPV16 is likely to remain undetected in some cervical cancer tissues because of low viral-copy-numbers. Putative high-risk HPV types (e.g., HPV67 and HPV82) might be high risk in Japan.
Teacher-student approach for lung tumor segmentation from mixed-supervised datasets
Authors: Fredriksen Vemund , Sevle Svein Ole M. , Pedersen André , Langø Thomas , Kiss Gabriel , Lindseth Frank
Published: April 2022

Purpose

Cancer is among the leading causes of death in the developed world, and lung cancer is the most lethal type. Early detection is crucial for better prognosis, but can be resource intensive to achieve. Automating tasks such as lung tumor localization and segmentation in radiological images can free valuable time for radiologists and other clinical personnel. Convolutional neural networks may be suited for such tasks, but require substantial amounts of labeled data to train. Obtaining labeled data is a challenge, especially in the medical domain.

Methods

This paper investigates the use of a teacher-student design to utilize datasets with different types of supervision to train an automatic model performing pulmonary tumor segmentation on computed tomography images. The framework consists of two models: the student that performs end-to-end automatic tumor segmentation and the teacher that supplies the student additional pseudo-annotated data during training.

Results

Using only a small proportion of semantically labeled data and a large number of bounding box annotated data, we achieved competitive performance using a teacher-student design. Models trained on larger amounts of semantic annotations did not perform better than those trained on teacher-annotated data. Our model trained on a small number of semantically labeled data achieved a mean dice similarity coefficient of 71.0 on the MSD Lung dataset.

Conclusions

Our results demonstrate the potential of utilizing teacher-student designs to reduce the annotation load, as less supervised annotation schemes may be performed, without any real degradation in segmentation accuracy.
Pre-exposure prophylaxis (PrEP) uptake and service delivery adaptations during the first wave of the COVID-19 pandemic in 21 PEPFAR-funded countries
Authors: Kerzner Michael , De Anindya K. , Yee Randy , Keating Ryan , Djomand Gaston , Stash Sharon , Rana Sangeeta , Kimmel Allison , Eakle Robyn , Klucking Sara , Patel Pragna ,   on behalf of the PEPFAR HIV Pre-exposure Prophylaxis Collaborators
Published: April 2022

Background

Mitigation measures for the first wave of the COVID-19 pandemic and burden on health systems created challenges for pre-exposure prophylaxis (PrEP) service delivery. We examined PrEP uptake in PEPFAR programs before and after the start of the COVID-19 pandemic.

Methods

We studied two PEPFAR program monitoring indicators, using routine Monitoring, Evaluation, Reporting (MER) indicators capturing uptake of PrEP (PrEP_NEW) and overall use of PrEP (PrEP_CURR). We also analyzed descriptive program narratives to understand successes and challenges field teams encountered after the start of the COVID-19 pandemic. To assess changes in coverage of PrEP across 21 countries, we calculated the “PrEP to need ratio” (PnR) using a published methodology. We defined the pre-COVID time period as April 1, 2019 –March 31, 2020 and the COVID time period as April 1, 2020 –March 31, 2021.

Findings

The total number of persons who initiated PrEP increased by 157% from 233,250 in the pre-COVID-19 period compared with 599,935 in the COVID-19 period. All countries, except five, noted significant increases in PrEP uptake. PrEP uptake among adolescent girls and young women (AGYW) increased by 159% from 80,452 AGYW in the pre-COVID-19 period to 208,607 AGYW in the COVID-19 period. There were 77,430 key populations (KP) initiated on PrEP in the pre-COVID-19 period and 209,114 KP initiated in the COVID-19 period (a 170% increase). The PnR increased 214% in the COVID-19 period across all PEPFAR-supported countries. Adaptations, such as multi-month dispensing (MMD) of PrEP; virtual demand creation activities; decentralized, community-based and virtual service delivery, were implemented to maintain PrEP services.

Conclusions

PEPFAR programs continued to maintain and initiate new clients on PrEP despite the challenges posed by the COVID-19 pandemic. Adaptations such as MMD of PrEP and use of technology were vital in expanding service delivery and increasing PrEP coverage.

Funding

This project has been supported by the U.S. President’s Emergency Plan for AIDS Relief.
Mycobacterium avium subsp. paratuberculosis and microbiome profile of patients in a referral gastrointestinal diseases centre in the Sudan
Authors: Elmagzoub Wisal A. , Idris Sanaa M. , Isameldin Maha , Arabi Nassir , Abdo Abdelmonem , Ibrahim Mustafa , Khan Md Anik Ashfaq , Tanneberger Franziska , Bakhiet Sahar M. , Okuni Julius B. , Ojok Lonzy , Gameel Ahmed A. , Abd El Wahed Ahmed , Bekaert Michaël , Mukhtar Mohamed E. , Amanzada Ahmad , Eltom Kamal H. , Eltayeb ElSagad
Published: April 2022

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne’s disease in animals with zoonotic potential; it has been linked to many chronic diseases in humans, especially gastrointestinal diseases (GID). MAP has been extensively studied in Europe and America, but little reports were published from Africa. Sudan is a unique country with close contact between humans and livestock. Despite such interaction, the one health concept is neglected in dealing with cases of humans with GID. In this study, patients admitted to the reference GID hospital in the Sudan over a period of 8 months were screened for presence of MAP in their faeces or colonic biopsies. A total of 86 patients were recruited for this study, but only 67 were screened for MAP, as 19 did not provide the necessary samples for analysis. Both real-time PCR and culture were used to detect MAP in the collected samples and the microbial diversity in patients´ faecal samples was investigated using 16S rDNA nanopore sequencing. In total, 27 (40.3%) patients were MAP positive: they were 15 males and 12 females, of ages between 21 and 80 years. Logistic regression analysis revealed no statistical significance for all tested variables in MAP positive patients (occupation, gender, contact with animal, milk consumption, chronic disease, etc.). A unique microbiome profile of MAP-positive patients in comparison to MAP-negative was found. These findings suggest that a considerable proportion of the population could be MAP infected or carriers. Therefore, increase awareness at community level is urgently needed to decrease the risk of MAP at human/animal interface. This study represents the first report of MAP in humans in the Sudan; nevertheless, a better view of the situation of MAP in humans in the country requires a larger study including patients with other conditions.
Intracellular Salmonella Paratyphi A is motile and differs in the expression of flagella-chemotaxis, SPI-1 and carbon utilization pathways in comparison to intracellular S. Typhimurium
Authors: Cohen Helit , Hoede Claire , Scharte Felix , Coluzzi Charles , Cohen Emiliano , Shomer Inna , Mallet Ludovic , Holbert Sébastien , Serre Remy Felix , Schiex Thomas , Virlogeux-Payant Isabelle , Grassl Guntram A. , Hensel Michael , Chiapello Hélène , Gal-Mor Ohad
Published: April 2022

Although Salmonella Typhimurium (STM) and Salmonella Paratyphi A (SPA) belong to the same phylogenetic species, share large portions of their genome and express many common virulence factors, they differ vastly in their host specificity, the immune response they elicit, and the clinical manifestations they cause. In this work, we compared their intracellular transcriptomic architecture and cellular phenotypes during human epithelial cell infection. While transcription induction of many metal transport systems, purines, biotin, PhoPQ and SPI-2 regulons was similar in both intracellular SPA and STM, we identified 234 differentially expressed genes that showed distinct expression patterns in intracellular SPA vs. STM. Surprisingly, clear expression differences were found in SPI-1, motility and chemotaxis, and carbon (mainly citrate, galactonate and ethanolamine) utilization pathways, indicating that these pathways are regulated differently during their intracellular phase. Concurring, on the cellular level, we show that while the majority of STM are non-motile and reside within Salmonella-Containing Vacuoles (SCV), a significant proportion of intracellular SPA cells are motile and compartmentalized in the cytosol. Moreover, we found that the elevated expression of SPI-1 and motility genes by intracellular SPA results in increased invasiveness of SPA, following exit from host cells. These findings demonstrate unexpected flagellum-dependent intracellular motility of a typhoidal Salmonella serovar and intriguing differences in intracellular localization between typhoidal and non-typhoidal salmonellae. We propose that these differences facilitate new cycles of host cell infection by SPA and may contribute to the ability of SPA to disseminate beyond the intestinal lamina propria of the human host during enteric fever.