bluuebunny/crossref_metadata_2025 huggingface dataset:
A review on the methods to mitigate the challenges in photovoltaic system
Authors: Zulkafli Rina Syazwani , Amin Nasrul Amri Mohd , Hashim Mohd Sani Mohamad , Basha Mohd Hafif , Majid Mohd Shukry Abdul , Daud Ruslizam , Zaman Izzuddin
Published: November 2018

The quantity of electricity produced from the photovoltaic (PV) system is depends on the PV panel’s performance itself. Recently, the challenges in the PV system have been greatly discussed by researchers and environmentalists. The non-uniform PV output power, partial shading conditions and high operating temperature of PV cells are the challenges that always known to reduce the PV system’s performance. This paper provides a literature review on the challenges and methods to mitigate the challenges. The future works involving of modelling and computational techniques also has been proposed to overcome the problems, hence, enhancing the PV system’s performance.
Performance Factors of the Photovoltaic System: A Review
Authors: Hussin Noor Syahirah Mohd , Amin Nasrul Amri Mohd , Safar Muhammad Juhairi Aziz , Zulkafli Rina Syazwani , Majid Mohd Shukry Abdul , Rojan Mohd Afendi , Zaman Izzuddin
Published: November 2018

Photovoltaic (PV) technology is one of the clean sustainable energy technology which sourced from the sun. However, there are many issues that can potentially degrade the system. This paper extensively discusses on the hybrid system power generation for the photovoltaic (PV) system. In addition, this paper also reviews the factor that affecting the photovoltaic system performance including the types of PV cell, the effect of ambient condition, system components, and the power quality characteristics. The performance of the monocrystalline type greater than the polycrystalline type around 5-7%. The usage of an inverter gives an impact with 8-20% of total energy losses. Finally, this paper summarises the future research work needed to overcome the drawback of the available photovoltaic systems.
EFFECT of DG Optimizing on overload Transmission line Stability
Authors: Ali Ali Abdullah , Abdalla Ahmed N , Ishat R.
Published: November 2018

Typical steady state studies always treat the peak power demands as the worst case conditions. Periods of light load are also critical in the assessment of the possible state of a power system. While heavy load conditions are generally associated with overload, low voltage and generation deficiency, light load conditions may give rise to over-voltage and undesirable reactive power requirements at generation side. This paper focus on study the effect of DG Optimizing on overload Transmission line Stability. The system dispatch constraints should be taken into account to compensate or varying DG generation output and to enhance the operational performance of power systems. This dispatching operation depends on the change of DG generation and the dispatching strategy. The impact of DG generation uncertainty is limited with the generation dispatching operation and should not be neglected in system analysis.
Impact of Soiling Rate on Solar Photovoltaic Panel in Malaysia
Authors: Sulaiman Shaharin A. , Razif M. Rosman M. , Han Tan Dei , Atnaw Samson M. , Tamili S. Norazilah A.
Published: November 2018

There are some weaknesses of using solar PV system especially when there is issue of soiling on the surface of solar PV panel. The consequences for absence of this such study can cause unanticipated cost in the operation of solar PV panel. The objective of this project is to study the trend of soiling rate over different time period and its effect on the performance of solar PV panel in Malaysia and to develop a simple prediction model for cleaning interval of solar PV system in Malaysia. The study was conducted on real-time basis on a building’s roof. Measurements of solar irradiance, voltage, current and the mass of dust collected were performed from both clean and dirty panels. It was discovered that the Monthly Test was significant with 4.53% of performance drop. Further analysis was conducted by running prediction model for cleaning interval. Intersection of graph plotting and fixed cleaning cost gives answer of cleaning interval that can be performed. It can be concluded that for every two and half month is the recommended time interval to perform regular cleaning to maximise electrical power generation by solar PV system in Malaysia.
Study on the Performance of a Thermo-Electric Generation Model with Two Different Materials of Heat Pipe-Heat Sink
Authors: Elghool Ali , Basrawi Firdaus , Ibrahim Hassan , Ibrahim Thamir K , Sulaiman Shaharin A. , Ishak M.
Published: November 2018

Heat sink lack of design is one reason that negatively affects the performance of thermoelectric modules. As compared to conventional cooling systems equipped with thermoelectric generators (TEG), heat pipe heat sink has various points of interest. Heat pipe heat sink is the most appropriate heat exchanger for medium temperature range under 300 °C. This paper demonstrates the effect of different materials of heat pipe-heat sink on the TEG performance. Two types of heat sinks were tested with TEG, one made from copper while the other from aluminium. The aim is to improve power output of TEG by an appropriate material of fins and metal block with heat pipes. The prototype was experimentally tested and the TEG cold side temperature, voltage and current were measured in both conditions, natural and forced convection. It was found that highest power output was achieved using copper heat sink in the case of forced convection, being 7.7 W whereas, lowest power output was obtained using aluminium heat sink in the case of natural convection, being 2.67 W. It is evident that copper heat sink is more effective than aluminium heat sink in terms of power output. However, both types of heat sink needs optimisation in terms of power output, cost and economic efficiency, while the results shown in this paper are just in terms of power output.
Investigation of Fuel Characterisation of Waste Sludge from Sewage Treatment Plants (STP)
Authors: Nor M.F.M. , Hassan S. , Said M.A. , Aris M.S.
Published: November 2018

Sewage treatment plants (STP’s) throughout Malaysia are facing escalating issues on sewage disposable and environmental impact. Investigation on the sewage sludge for possible fuel formulation as renewable energy is being considered. The characterization of waste sludge on its volatility, High Heating Value and Energy output value will provide a preliminary finding for usage as potential biomass fuel. Co-combustion of sewage sludge and coal provide another formulation for potential biomass fuel depend on its technical viability and economical input.
Development of Solar Powered Buggy Charging Station
Authors: Sakidin Hamzah , Nor Mohd Faizairi M. , Hassan Suhaimi , Basrawi Firdaus , Ahmad Asmala , Rahman Imran
Published: November 2018

The renewable energy became an essential demand for today’s world life for all its importance in decreasing pollution and keeping our environment clean. The solar car is a step in saving our environment and energy resources. The New project under Universiti Teknologi PETRONAS (UTP) - URIF grant is targeted to run the university Buggy using solar photovoltaic. The 48V Buggy Car Charging Station has been developed and installed at Property Management and Maintenance Office (PMMO), UTP. A new solar-powered buggy car is assembled in innovative manner with state-of-art material and component. The maximum solar voltage allowed for the system is 150V at 45Acharging rate and the maximum efficiency of MPPT/CHARGER could be as high as 98%.
Experimental Study on the Mechanical Properties of Biomass Briquettes from Different Agricultural Residues Combination
Authors: Law H.C. , Gan L.M. , Gan H.L.
Published: November 2018

Biomass has received tremendous attention as it is one of the best alternatives to replace the use of fossil fuels for energy generation. However, there are problems associated with the utilization of raw biomass which could be resolved through densification process. Besides, mixing between residues could produce a quality briquette, at the same time making good use on the biomass residues. Rice husk, sugarcane bagasse and spent coffee ground were selected as the biomass feedstocks for briquettes formation. The mixing ratios of 100:0, 80:20, 60:40, 20:80, 40:60 and 0:100 were used for three different combinations. The briquettes were then compacted at 300 bars and 150°C for 30 s. The mechanical properties of the briquettes were measured with respects to their shatter resistance, abrasive resistance as well as water resistance. The mechanical properties of the briquettes could be effectively improved by mixing between the residues as compared to the pure materials. The result showed that briquettes formed with 40: 60 of RH to SB; 20: 80 of RH to SCG and 20: 80 of SB to SCG were among the optimum mixing ratio for the respective combination fulfilling the specifications of the mechanical strength and durability.
A Review on Power Plant Maintenance and Operational Performance
Authors: Velayutham Puvanesan , Ismail Firas Basim
Published: November 2018

This paper presents the power plant maintenance scheduling and particle swarm optimization (PSO) technique to ensure economical and reliable operation of power system. Initially problems related to the power plant maintenance scheduling in modern power systems are briefed, also explaining the need and importance of an optimum and reliable power plant maintenance system. It briefly describes the maintenance scheduling of power plant by application of PSO technique. This paper proposes power plant maintenance scheduling of a power system based on minimization of the objective function considering the economical and reliable operation of a power system while satisfying the crew/manpower and the load demand.
Permittivity and Permeability Characterization of SiC and Ferro Metals for Structural Health Monitoring Utilization
Authors: Hussein Alaa Raad , Albarody Thar M. Badri , Yousf Puteri Sri Melor Bt M. , Abdullah Monis Abdulmanan , Al-Jothery Husam Kareem Mohsin
Published: November 2018

The need for wireless sensing technology has rapidly increased recently, specifically the usage of electromagnetic waves which becoming more required as a source of information. Silicon carbide (SiC) Nano particles has been used in this study, the material under test (MUT) was exposed directly to a microwave field to examine the electromagnetic behavior. The permittivity and permeability were investigated with different filler materials to approach best and optimal electromagnetic absorbing characteristics to assist engineers to monitor structure-based composite for defects evaluation that may occur during operation conditions or through manufacturing process. XRD, FESEM and both complex permittivity and permeability were measured for the pure materials that candidate for this study. The results showed that all the selected nanostructure material exhibit a good purity with proper electromagnetic properties in the X- band, this can lead to absorbing and transmission properties that can be used in monitoring structures or manufactured part during fabrication process.
Mechanical Fault Detection on Electrical Machine: Thermal Analysis of Small Brushed DC Motor with Faulty Bearing
Authors: Wahab Abbas A. , Abdullah N. Fatimah , Rasid M.A.H.
Published: November 2018

Direct current motors (DC motor) are used in the small electric devices commonly. DC motor are cheap and easy to install, thus their popularity. Despite the popularity, faults occur which make diagnosis and detection of faults very important. It avoids financial loss and unexpected shutdown operation causes by these faults. This paper presents an analysis of temperature profile of the much famous small Brushed DC motor with a faulty bearing. The temperature data of healthy DC motor and DC motor with faulty bearing were measured by thermocouple and recorded using data logger in real time until steady state temperature, under different load. The analysis on the steady state temperature allow to conclude that bearing fault can clearly be recognised through characteristics temperature difference with a healthy motor.
Study the Effects of Photon Radiation on Power MOSFET for Harsh Environment Application
Authors: Azwan Erman , Kannan Ramani , Lee Lini , Krishnamurthy Saranya
Published: November 2018

The rapid growth of the advanced technologies in power electronics system gives a challenge to the electronic device to sustain with the modern technologies nowadays. The challenges are also including the place where the system was installed for example the application in the harsh environment. Harsh environment application requires an electronic device deals with radiation pollution. Hence, the electronic device will suffer from this phenomenon and make the whole system to malfunction and break down. Power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is one type of electronic device that is the most broadly for high voltage and high switching speed application. The aim of this paper is to studies the photon radiation effect toward the Power MOSFET performance. The study focus on the changing of the electrical characteristics of the device after radiated with photon radiation. Process simulation and Device simulation tools in Sentaurus Synopsys Software used for the research to validate all the theory.
Effective Renewable Source Integration using Unified Power Quality Conditioner with Power Quality Enhancement in Three Phase System
Authors: Suresh P. , Gowri Manohar T.
Published: November 2018

This paper proposes a modified control strategy for unified Power Quality conditioner to alleviate voltage and current abnormalities in three phase system. Renewable source integration and nonlinear loads depreciates Power Quality of the system. Active Power Filters play a paramount role in alleviating PQ disturbances. To deal with current imperfections and reactive power compensation, modified dq controller is proposed for shunt controller. ANFIS-dq control strategy is proposed for Series Controller to suppress voltage imperfections Photovoltaic unit is optimally connected at DC link of UPQC for supporting controlling action and to deliver real power Proposed optimal renewable source integrated UPQC performance is studied with traditional PI and ANFIS controller. MATLAB / SIMULINK platform is used for analyzing proposed system performance.
A Simulated Model for Assesing the Line Condition of Onshore Pipelines
Authors: Basha Shaik Nagoor , Rao Pedapati Srinivasa
Published: November 2018

Pipelines are considered safest mode of transport because of their limited number of facilities. It is therefore very important to monitor and optimize their operation and reduce their facilities to acceptable limits. Hence, it is an immediate requirement to assess and predict condition of existing oil and gas pipelines and to prioritize the planning of their inspection on a timely basis. Therefore, this study presents the development of models based on specific factors, that can predict the condition of onshore oil and gas pipelines. The model was developed using BPN (Back Propagation Network) techniques based on historical inspection data collected from the oil and gas fields. The model is expected to help pipeline operators to assess the condition of existing oil and gas pipelines and hence prioritize their inspection and rehabilitation operations.
Design and Analysis of 24 Hours Solar Panel
Authors: Francis John , Jawahar Denie Sam , Paul Antony John , Lydia M
Published: November 2018

The design of a 24/7 solar panel using artificial method of producing Infra-Red (IR) has been proposed in this paper. This arrangement ensures that the solar panel can produce energy even during night time. The major disadvantage of a solar panel is that it cannot be used during night time and when the panel is shaded. Our project aims to eliminate these disadvantages of solar panel. In this work, a Light Dependent Resistor (LDR) resistor is used to sense day or night conditions and the analog sensed value is sent to the PIC microcontroller. During night hours, only specified load will be on, so that the battery works without getting discharged fully even in the midnight. The IR Light Emitting Diodes (LEDs) that are used in night are placed in inner side of the shutter which is placed on top of the panel. The shutter is opened and closed using a motor which is controlled by using relay. The charge and discharge conditions of the battery are monitored by a Global System for Mobile Communications (GSM) module. The efficiency and economic analysis of the system has been presented.
Professioneller Informationsaustausch
Authors: Beese Florian
Published: November 2018

Auf Intensivstationen ist die Weitergabe von Informationen besonders wichtig. Ob
Dienstwechsel oder Verlegung von Patienten – alle betreuenden Pflegenden sind
auf eine angemessene Übergabe und die Kenntnis sicherheitsrelevanter Aspekte im
Umgang mit den Patienten angewiesen. Dennoch sind übermittelte Informationen oft
falsch oder unzureichend. Wie es dazu kommt und was man dagegen tun kann,
beleuchtet der folgende Beitrag und fokussiert dabei auf das spezielle Setting
der Respiratory Care Unit.
Sinnvoll für den Patienten, hilfreich fürs
Personal
Authors: Bräunig Jochen , Gottschalk Antje
Published: November 2018

Frühmobilisation wirkt sich erwiesenermaßen auf Intensivpatienten positiv aus.
Dabei ist auch die richtige Positionierung des Patienten wichtig, die sich mit
geeignetem Lagerungsmaterial erreichen lässt. Herkömmliches Material ist dabei
oft ungeeignet, wird falsch oder gar nicht benutzt und kann zu gefährlichen
Situationen für den Patienten führen. An der Uniklinik Münster haben die beiden
Autoren daher anhand eines eigens entwickelten und an die Betten der
Intensivstation angepassten Lagerungswürfel-Sets versucht herauszufinden, wie
sich dieses Hilfsmittel bei den Pflegekräften im täglichen Umgang bewährt.
Levothyroxine Therapy Achieves Physiological FT3/FT4 Ratios at Higher than Normal TSH Levels: A Novel Justification for T3 Supplementation?
Authors: Strich David , Chay Cherut , Karavani Gilad , Edri Shalom , Gillis David
Published: November 2018

In euthyroidism, as thyroid Stimulating hormone (TSH) levels increase, the free triiodothyronine (FT3) to free thyroxine (FT4) ratio increases. The aim of this study was to assess if beyond the euthyroid range of TSH levels FT3/FT4 ratio continues to increase and if levothyroxine treatment reduces this ratio, possibly through TSH suppression. This cross sectional retrospective study included a total of 77 832 patients [age 22.76±15.17 years (4 days to 112 years)] evaluated and treated in community clinics between January 2009 and September 2013. Blood samples drawn in community clinics for which TSH, FT4, FT3, age, and gender were available were included. Tests with TSH below 0.5 IU/l were excluded as were samples taken during pregnancy. The FT3/FT4 ratio continued to increase significantly even with TSH above 50 mIU/l (p for trend<0.001) with an increase of more than 50% over the entire TSH range. With increasing age and female gender, the phenomenon was less prominent (p<0.001). Levothyroxine treated patients had significantly lower FT3/FT4 ratios in comparison to untreated patients up to TSH levels of 5.0 mIU/l. In conclusion, increasing TSH increases FT3/FT4 ratio even with severe hypothyroidism, less so with aging. With levothyroxine therapy, a ratio similar to untreated patients is achieved at TSH of above 5.0 mIU/l. Since T3 suppresses TSH better than T4, administration of T3 would likely normalize the FT3/FT4 ratio at a lower, ostensibly more physiological, TSH level. This could be seen as a rationale for add-on T3 therapy.
Jens Spahn und die Selbstverwaltung: Zuckerbrot und Peitsche
Authors: Mau Jens
Published: November 2018

Bundesgesundheitsminister Jens Spahn feuert genüsslich Giftpfeile gegen DKG, GKV und KBV. Doch eine Demontage der Selbstverwaltung hat der Minister nicht im Sinn, wie man zum Beispiel beim Thema Telematikinfrastruktur (TI) sieht.
Rechtskolumne: BSG-Entscheidung zu NUB wirft erhebliche Fragen auf
Authors: Rybak Christian
Published: November 2018

Kliniken dürfen neue Untersuchungs- und Behandlungsformen (NUB) zu Lasten der GKV erbringen, solange diese Erbringung nicht durch den G-BA verboten wurde. Voraussetzung ist jedoch, dass die NUB das Potenzial für eine erforderliche Behandlungsalternative bieten.
Klinikunternehmen: Auf-/Absteiger des Monats
Authors: Schmidt Hartmut
Published: November 2018

Börsenexperte, analysiert für kma die Jahresabschlüsse* ausgewählter Kliniken

* Quelle: elektronischer Bundesanzeige, Geschäftsberichte
Cloud-Computing: eHealth aus der Wolke
Authors: Krolop Sebastian , Benthin Florian , Knahl Constanze
Published: November 2018

Cloud-Computing gewinnt auch in Kliniken zunehmend an Bedeutung. Über das Internet bereitgestellte Lösungen verändern nicht nur Verwaltung und Logistik – im klinischen Bereich geht es zum Beispiel um die Nutzung elektronischer Patientenakten am Point-of-Care.
Virusdiagnostik: Erlanger Transfusionsmedizin führt neues Prüfverfahren ein
Authors: Männel Franziska
Published: November 2018

Urlauber, die in einem Risikogebiet für Virusinfektionen wie Malaria und auch dem West-Nil-Virus unterwegs waren, dürfen im Anschluss aus Sicherheitsgründen vier Wochen kein Blut spenden.
Krankenhaushygiene: Mit Trockennebel gegen MRSA
Authors: Kucera Martin
Published: November 2018

Im täglichen Kampf gegen Viren, Bakterien und Keime setzt die BDH-Klinik Greifswald ein spezielles Wasserstoffperoxid-Verneblungsgerät ein. Es besitzt ein sehr breites Wirkungsspektrum, desinfiziert auch schwer zu erreichende Flächen in Funktionsbereichen und Patientenzimmern und kommt dabei ganz ohne Feuchtigkeit aus.
Elektrofischkatheter: Ein Fisch revolutioniert die Therapie von Herzrhythmusstörungen
Authors: Wakili Reza
Published: November 2018

Herz-Kreislauf-Erkrankungen zählen mit jährlich rund 350 000 Sterbefällen zu den häufigsten Todesursachen. Angesichts der älter werdenden Bevölkerung sind neue Technologien in der Kardiologie unverzichtbar. Intelligente Lösungen wie der in Deutschland mitentwickelte Elektrofischkatheter machen die Therapien für Patienten schneller und sicherer.
Angiografiesysteme: Das Navi für den Operationssaal
Authors: Kucera Martin
Published: November 2018

Nachdem Anfang des Jahres der erste Hybrid-OP des Uniklinikums Dresden den Betrieb aufgenommen hat, folgte im August ein zweiter Saal dieses Typs. Die Besonderheit ist das darin installierte robotergeführte Röntgengerät. Die Klinik für Viszeral-, Thorax- und Gefäßchirurgie will damit die Entwicklung navigierter Operationen vorantreiben.
Qualitätsmanagement und Agilität: Spannende Verschmelzung
Authors: Holtel Markus , Pilz Stefan , Sommerhoff Benedikt
Published: November 2018

Viele Praktiker im Gesundheitswesen fremdeln bis heute mit dem Qualitätsmanagement. Etwas Agilität gibt dem Bereich frische Impulse und kann sie mit der ungeliebten Materie versöhnen. Einige Beispiele lassen aufhorchen.
ÖVKT-Tagung 2018: Klimawandel im Gesundheitswesen
Authors: Thalmayr Maria
Published: November 2018

Um schneller und angemessen auf sich ändernde Bedingungen reagieren zu können, brauchen Gesundheitseinrichtungen einen Klimawandel: von relativ starren, konservativen Strukturen hin zu einem proaktiven Innovationsklima.
Sprechstunde in der PR-Ambulanz: Müssen Journalisten einen Beitrag zur Freigabe vorlegen?
Authors: Endele Kerstin
Published: November 2018

Kerstin Endele ist zur Hälfte Journalistin und zur Hälfte Biochemikerin. Seit mehr als 15 Jahren ist sie Expertin für Gesundheitskommunikation und war fünf Jahre Kommunikationschefin und Pressesprecherin der Charité. Wenn sie nicht Klinikvorstände aus Krisen rettet und Pressesprechern diverser Krankenhäuser dabei hilft, ein bisschen Strategie ins übliche Chaos zu bringen, betreibt sie mit der PR-Ambulanz (www.pr-ambulanz.com) einen der größten Blogs zur Klinikkommunikation in Deutschland.
Percutaneous Cement Injection for the Palliative Treatment of Osseous Metastases: A Technical Review
Authors: Tselikas Lambros , Gravel Guillaume , de Baère Thierry , Deschamps Frederic , Yevich Steven
Published: November 2018

The technical art to percutaneous injection of polymethyl methacrylate (PMMA) cement for the palliative treatment of osseous metastases is not without pitfalls. Pathologic fracture, cortical bone erosion, large lytic tumor, aggressive tumor biology, and tumor vascularity may increase the risk of cement leakage or limit complete consolidation. A calculated and determined approach is often necessary to achieve satisfactory patient-tailored results. This article reviews the challenges and potential complications during the consolidation of osseous metastases. Case examples are presented to facilitate early detection of impending cement leakage, minimize procedural risks, and provide management suggestions for complications. Technical pearls are provided to refine consolidative techniques and improve the comprehensive treatment of painful osseous metastases.
Giovanni Alfonso Borelli: The Precursor of Medial Pivot Concept in Knee Biomechanics
Authors: Piolanti Nicola , Polloni Simone , Bonicoli Enrico , Giuntoli Michele , Scaglione Michelangelo , Indelli Pier
Published: November 2018

A new philosophy of science and medicine had spread throughout the 17th-century Italy: the “Scientific Revolution.” Giovanni Alfonso Borelli (1608–1679) was one of the most charismatic and brilliant scientists of his generation in Europe. He extended to biology the rigorous analytic methods developed by his indirect mentor Galileo in the field of mechanics. In his masterpiece “De Motu Animalium,” Borelli analyzed structure, motion, balance, and forces concerning almost all the principal joints of the human body, in static and dynamic situations. In particular, he accurately studied the anatomy and biomechanics of the knee joint. He sustained that femoral condyles shift backward during flexion, allowing a wider range of movement. Furthermore, he observed that, when the knee flexes, the lateral condyle moves backward more than the medial condyle: this concept is nowadays known as medial pivoting. The aim of this article is to describe the life and work of this important Italian scientist and to present his unrecognized contribution to modern knee biomechanics.
Estabilización de la luxación inveterada de la quinta articulación carpo-metacarpiana mediante tenosuspensión con banda de extensor cubital del carpo
Authors: Hernández-Cortés Pedro , Rodríguez Laura , Gil María Isabel
Published: November 2018

Las fracturas luxaciones de la articulación carpometacarpiana (CMC) del 5° dedo pasan desapercibidas con frecuencia. El diagnóstico y tratamiento tardíos conlleva con frecuencia malos resultados funcionales por dolor, pérdida de fuerza de prensión y el desarrollo de artrosis CMC. El tratamiento de las luxaciones inveteradas es un reto. Se han propuesto numerosas técnicas quirúrgicas al respecto. Presentamos una modificación de una tenoplastia de supensión, utilizando una banda del tendón del Extensor Carpi Ulnaris. Creemos que esa técnica tiene varias ventajas sobre otros procedimientos paliativos. En primer lugar, se preserva la movilidad del 5° metacarpiano que se estabiliza sólo por ligamentoplastia al 4° metacarpiano. En segundo lugar, mantiene la longitud del 5° radio. En tercer lugar, admite una variante en la que la realización de túneles óseos en 4° y 5° metacarpiano favorece una mejor alineación, evitando la disrotación del 5° dedo. Pensamos que esa técnica es el mejor tratamiento en las luxaciones inveteradas de la 5ª articulación CMC.
Pyroelectric waste heat energy harvesting using the Olsen cycle on Pb(Zr, Ti)O3-Pb(Ni, Nb)O3 ceramics
Authors: Siao An-Shen , McKinley Ian M. , Chao Ching-Kong , Hsiao Chun-Ching , Pilon Laurent
Published: November 2018

This paper is concerned with direct energy conversion of waste heat into electrical energy by performing the Olsen cycle on lead nickel niobate zirconate titanate (PNNZT) pyroelectric ceramics undergoing a relaxor-ferroelectric phase transition. First, isothermal bipolar displacement vs. electric field hysteresis loops were measured for different temperatures and electric field spans. The Curie temperature varied between 150 °C and 240 °C as the electric field increased from zero up to 3 MV/m. The energy and power densities of the Olsen cycle on PNNZT were measured by cycling the specimens over a wide range of temperatures, electric fields, and frequencies. A maximum energy density of 1417 J/L/cycle was recorded with 200 μm thick PNNZT cycled at 0.033 Hz between temperatures 20 °C and 240 °C and electric fields 0.3 MV/m and 9.0 MV/m. To the best of our knowledge, this is the largest energy density ever obtained experimentally for any pyroelectric material. In addition, a maximum power density of 78 W/L was measured by cycling the material temperature between 20 °C and 220 °C and applying the electric field between 0.3 MV/m and 9.0 MV/m at 0.09 Hz.
Identification and compensation of quadratic terms of a space electrostatic accelerometer
Authors: Ma Yun , Bai Yan-Zheng , Li Hong-Yin , Zhou Ze-Bing , Zhou Zheng
Published: November 2018

The ultra-sensitive space electrostatic accelerometers have been successfully employed in the Earth’s gravity field recovery missions and the space gravitational experiments. Since the accelerometer output in the measurement bandwidth can be influenced by the orbital high-frequency disturbances due to the second-order nonlinearity effects, the relevant quadratic term must be accurately compensated to guarantee the accuracy of the electrostatic accelerometer. In this paper, three sources of the quadratic term are studied and formulated. They are the offset of the test mass in the housing due to the bias of the capacitive position transducer, the asymmetry of the electrode area, and the asymmetry of the actuation electronics. Two feasible compensation methods and an identification means are proposed. Compensation is achieved by adjusting the test mass actual working position or the asymmetry factor of the feedback actuation voltage. Identification is conducted by applying a periodic high frequency signal on the electrodes. Finally, the proposed methods are demonstrated, in view of future space applications, by suspending the accelerometer test mass on a torsion pendulum.
Meaningful improvements on structural-thermal-electronic properties of copper based on 3D nitrogen (N) doped-carbon nanotubes (CNTs) interface fabricated by nano-self-assembly-sintering-modification
Authors: Ye Xianzhu , Li Ming , Li Daoru , Li Bin , Zhang Yafei
Published: November 2018

The development of a material with high ampacity to allow current to flow through narrow channels is one of the most promising ways to address the progressive miniaturization and light weight of electronic devices. The efficient synergistic electron transmission by compounding 1D/2D carbon materials with a metal matrix via various methods in recent years has attracted great research interest due to their potential utilization in electronics. In this study, a copper (Cu) matrix with a 3D nitrogen (N) doped-multi-walled carbon nanotubes (MCNTs) interface with prominent physical features is reported and fabricated, involving the use of nano-self-assembly-heat-modification by adopting polyethyleneimine-nano-Cu and carboxyl MCNTs. Young's modulus was enhanced from 28.8 to 92.2 GPa due to a higher efficiency of stress transfer and interfacial adhesion, and the hardness fitted by Gauss distribution was increased by ∼69% (∼39.7 HRC). Toward the stability after a modification of vacuum reduction sintering, the initial oxidation temperature (Td) was increased largely from 232 °C to 286 °C, and thermal conductivity was enhanced eminently from 358 to 548 W/(m K) due to more efficient electron/phonon motion. Moreover, synergistic electron transmission endowed the final Cu-N-CNTs with a higher ampacity (7.23–16.98 × 104 A cm−2), which could be further observed by the time-evolution of electrical resistivity under a constant current density. The improved physical features state that the assembled 3D N-CNTs interface possesses prominent characteristics and potential for directing the deep applications of 1D or 2D carbon materials in electronic science.
The energy distribution of the electron beams in z-pinches with different load geometries
Authors: Wallace M. S. , Hammel B. D. , Haque S. , Neill P. , Presura R.
Published: November 2018

A wide variety of z-pinches are host to energetic electron beams whose energies and origins have yet to be sufficiently characterized. Knowing the electron energies and currents of these electron beams can give insight into the mechanism responsible for the acceleration of the electrons to such high energies. Measurements with a magnetic analyzer have been carried out to determine the energy distribution of electron beams on a variety of aluminum wire array z-pinch geometries at the Nevada Terawatt Facility at the University of Nevada, Reno. These measurements show that as the geometry of the wire array is changed so that the initial angle of inclination, or necking shape, is enhanced, there is an increase in electron beam activity and electron energies. Measurements such as these can be useful to benchmark spectroscopic techniques used to characterize these energetic beams and give insight into the mechanisms responsible for the generation of such energetic beams in z-pinch plasmas.
Lewis-Riesenfeld quantization and SU(1, 1) coherent states for 2D damped harmonic oscillator
Authors: Lawson Latévi M. , Avossevou Gabriel Y. H. , Gouba Laure
Published: November 2018

In this paper, we study a two-dimensional rotationally symmetric harmonic oscillator with time-dependent frictional force. At the classical level, we solve the equations of motion for a particular case of the time-dependent coefficient of friction. At the quantum level, we use the Lewis-Riesenfeld procedure of invariants to construct exact solutions for the corresponding time-dependent Schrödinger equations. The eigenfunctions obtained are in terms of the generalized Laguerre polynomials. By means of the solutions, we verify a generalization version of Heisenberg’s uncertainty relation and derive the generators of the su(1, 1) Lie algebra. Based on these generators, we construct the coherent states à la Barut-Girardello and à la Perelomov and respectively study their properties.
Note: An automatic liquid nitrogen refilling system for small (detector) Dewar vessels
Authors: Deniz E. , Eberl K. B. , Bredenbeck J.
Published: November 2018

Many infrared spectroscopy setups are in principle stable enough to run overnight or longer, but the detector’s Dewar vessel must be refilled manually with liquid nitrogen (LN2) every couple of hours. Commercial automatic LN2 refilling systems work reliably only for large Dewars. Here, we present a refilling system which can non-invasively be applied to already installed small Dewars. The system reliably refills LN2 once it has dropped below an adjustable level, with quick refilling (<3 min) for a 0.6 l Dewar. Our design protects the setup and the detector from overflowing or running without LN2.
Strong angular dependence of resonant states in 2D dielectric cylinder rings
Authors: Andueza Ángel , Pérez-Conde Jesús , Sevilla Joaquín
Published: November 2018

We investigate collective resonators made of dielectric cylinders assembled as two-dimensional regular octagons and decagons. These structures exhibit collective resonance states that change their intensity with the incident radiation angle. While most parts of the spectra present small or even null variation, one of these resonances presents high-sensitivity to the incidence angle. This strong variation is well characterized in terms of the electric field intensity distribution of a resonant state where all the cylinders show the lowest order Mie resonance and the neighbors alternate their polarities. The collective state is optimally excited when radiation impinges on a vertex of the polygonal arrangement of cylinders, while the response decreases to its minimum when the incident field hits an edge (two cylinders at the same time). The resonant state and its high dependence on the excitation incidence angle have been found in both octagonal and decagonal configurations for different dielectric permittivity values. In addition, the scalability of Maxwell equations warranties the same behavior if the whole system is downscaled to terahertz or optic frequencies. The study was performed by finite integration time domain calculations of scattering and transmission for different incidence angles. Experimental measures in the microwave range were taken from photonic molecule prototypes made of centimeter-scale glass cylinders (ɛ = 4.5). We find an overall excellent agreement between measurements and simulations. We propose that photonic molecules made of polygonal rings of dielectric cylinders are an ideal structure to build angle sensors using the strongly varying state that they present.
Study of the oxidation at the Al2O3/GaSb interface after NH4OH and HCl/(NH4)2S passivations and O2 plasma post atomic layer deposition process
Authors: Lechaux Y. , Fadjie-Djomkam A. B. , Pastorek M. , Wallart X. , Bollaert S. , Wichmann N.
Published: November 2018

In this work, the Al2O3/GaSb interface has been studied by x-ray photoelectron spectroscopy in order to improve interfacial and electrical properties of metal–oxide–semiconductor structures based on GaSb. First, different passivations using NH4OH or (NH4)2S were studied with a dilution of 4% and 5%, respectively, in order to reduce native oxides on the GaSb surface. Then, we considered the oxidation of the Al2O3 and GaSb surface after treatments with an oxygen (O2) plasma post atomic layer deposition (ALD) process and with post deposition annealing at different temperatures. We found that (NH4)2S passivation leads to a lower quantity of native oxides on the GaSb surface and that the O2 plasma post ALD process enables the formation of an oxygen-rich layer within the Al2O3 at the interface reducing the GaSb surface oxidation after post deposition annealing of the oxide.
Mechanism of large tunable thermal transport in graphene with oxygen functional groups
Authors: Wang Jian , Wang Lei , Xing Yu-heng , Liu Tian-xing , Zhang Shi-tian
Published: November 2018

Tuning thermal transport in low-dimensional systems such as nanowires and graphene is crucial for both conventional electronic device cooling and nanoscale energy conversion. Here, we explore a connection between surface functionalization and heat transport in functionalized graphene by oxygen functional groups from the first-principles approach. Compared to the high thermal conductivity of pristine graphene, our calculation demonstrates that the thermal conductivity of functionalized graphene has remarkably decreased by more than one order of magnitude, which is consistent with the experimental observations. Our analysis of phonon modes confirms that highly suppressed phonon lifetimes are responsible for this great reduction of thermal conductivity in functionalized graphene. We elucidate that the greatly shortened phonon lifetimes mainly result from the expanded phase space for phonon scatterings, while contributions from lattice anharmonicity may be negligible. Our findings shed light on the mechanism of thermal transport in oxygen-functionalized graphene and offer some valuable insights into a new strategy for tuning thermal conductivity and the exploration of new thermoelectric devices.
Effects of ultraviolet photon irradiation and subsequent thermal treatments on solution-processed amorphous indium gallium zinc oxide thin films
Authors: Takamori Yuki , Morimoto Takaaki , Fukuda Nobuko , Ohki Yoshimichi
Published: November 2018

Effects of exposure to ultraviolet (UV) photons and thermal treatments on solution-processed amorphous indium gallium zinc oxide (a-IGZO) films were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. As a result, oxygen vacancies obviously become more abundant in the films sintered at 250 or 300 °C by the exposure to 7.21 eV photons and less abundant by the subsequent thermal treatment at 250 °C in air. The drain current also clearly becomes smaller in a thin film transistor fabricated using the IGZO film in a manner opposite to the abundance of oxygen vacancies. That is, the drain current becomes smaller by the UV irradiation and returns to the original high value by the subsequent thermal treatment. This indicates that oxygen vacancies act as trapping centers or scattering centers of electrons. In addition, the reversible change of the drain current with the cycle of UV irradiation and the thermal treatment opens the possibility of the use of the IGZO films as a UV sensor.
Subwavelength acoustic topological edge states realized by zone folding and the role of boundaries selection
Authors: Dai Hongqing , Qian Muyan , Jiao Junrui , Xia Baizhan , Yu Dejie
Published: November 2018

This article reports a realization of subwavelength acoustic topological edge states realized by a triangular array of hexagonal columns with Helmholtz resonators. Using the strategy of zone folding, Dirac cones can be folded into double Dirac cones to construct pseudo-spin states. By adjusting the length of both the center and corner units, topological phase transition as well as the common bulk bandgap can be achieved. The calculated results show that the acoustic metamaterials with different boundaries exhibit different bulk transmission properties. Topological acoustic metamaterials can be combined with different boundaries to construct nine different interfaces, and the simulation results show that nine different interfaces can exhibit robust, weak, and even disappearing topological edge states. We manufacture the samples and carry out experiments to test the transmission spectra of nine different interfaces. Experimental results demonstrate that a sound wave can transmit well along the topological interface 1 path compared with the other eight interface paths. This study provides a simple approach to create acoustic topological edge states at the subwavelength scale and experimentally confirms the influence of boundaries selection on acoustic topological insulators.
Adiabatic population transfer between electronic states of LiH molecule in two picosecond laser pulses
Authors: Niu Ying-Yu , Wang Rong
Published: November 2018

The population transfer of stimulated Raman adiabatic passage (STIRAP) is investigated using a time-dependent quantum wave packet method. The population is transferred from an initial state to a target state through the interaction of the external laser field with the permanent dipole moment and the transition dipole moment. The laser field is composed of an infrared pulse and a near ultraviolet pulse. The two pulses with small detunings are more efficient to achieve the STIRAP transition. The process of STIRAP is sensitive to the detunings of the two pulses. When the two detunings are the same in a Λ transition or the positive detuning of the pump pulse is equal to the negative detuning of the Stokes pulse in a ladder transition, the final population in the intermediate state can be eliminated and the target population is increased.
Non-invasive low charge electron beam time-of-arrival diagnostic using a plasmonics-enhanced photoconductive antenna
Authors: Snively E. C. , Yardimci N. T. , Jacobson B. T. , Jarrahi M. , Musumeci P. , Murokh A.
Published: November 2018

The use of a plasmonics-enhanced photoconductive antenna (PCA) optically gated by a near infrared (NIR) pulse enables non-invasive time-of-arrival measurements of a low charge electron beam with respect to the NIR reference, achieving picosecond resolution. The measured signal values show the expected scaling with the beam charge and distance from PCA to the beam axis, as the PCA samples the electric field of the passing electron beam. We operate the device with an NIR spot size much larger than the PCA active-area, resulting in a very simple optical setup and alignment procedure, making the plasmonics-enhanced PCA a preferred alternative to more complex timing diagnostics for applications requiring non-invasive picosecond or sub-picosecond timestamping.
Open-channel microfluidic diodes based on two-tier junctions
Authors: Hyun Woo Jin , Kumar Satish , Francis Lorraine F. , Frisbie C. Daniel
Published: November 2018

Precise control of capillary flow is of great importance in open-channel microfluidic technology. We report a compelling strategy to achieve unidirectional liquid flow in open capillary channels. The key flow-rectifying feature is a microfluidic junction between two open channels: a small cross-section, shallower channel, and a large cross-section, deeper channel. Liquids flow from the large channel to the small channel, but flow in the opposite direction is blocked at the junction. Experiments and computational analysis show that rectification follows directly from the Gibbs criterion for flow over step edges. The unidirectional flow behavior is independent of the liquid contact angle and surface tension and also of changes in channel dimensions, suggesting broad applicability for controlling flow. Specifically, we show that the junction structure can be utilized to facilitate the fabrication of electronic devices from functional inks delivered to open capillaries.
“Phase diagram” for viscoelastic Poiseuille flow over a wavy surface
Authors: Haward Simon J. , Page Jacob , Zaki Tamer A. , Shen Amy Q.
Published: November 2018

We experimentally examine the Poiseuille flow of viscoelastic fluids over wavy surfaces. Five precision microfabricated flow channels are utilized, each of depth 2d = 400 μm, spanwise width w = 10d and with a sinusoidal undulation of amplitude A = d/20 on one of the spanwise walls. The undulation wavelength λ is varied between each of the channels, providing dimensionless channel depths α in the range 0.2π ≤ α = 2πd/λ ≤ 3.2π. Nine viscoelastic polymer solutions are formulated, spanning more than four orders in elasticity number El and are tested in the wavy channels over a wide range of Reynolds and Weissenberg numbers. Flow velocimetry is used to observe and measure the resulting flow patterns. Perturbations to the Poiseuille base flow caused by the wavy surfaces are quantified by the depth of their penetration P into the flow domain. Consistent with theoretical predictions made for wavy plane-Couette flow [J. Page and T. A. Zaki, “Viscoelastic shear flow over a wavy surface,” J. Fluid Mech. 801, 392–429 (2016)], we observe three distinct flow regimes (“shallow elastic,” “deep elastic” and “transcritical”) that can be assembled into a “phase diagram” spanned by two dimensionless parameters: α and the depth of the theoretically predicted critical layer Σ∼El. Our results provide the first experimental verification of this phase diagram and thus constitute strong evidence for the existence of the predicted critical layer. In the inertio-elastic transcritical regime, a surprising amplification of the perturbation occurs at the critical layer, strongly influencing P. These effects are of likely importance in widespread inertio-elastic flows in pipes and channels, such as in polymer turbulent drag reduction.