This document summarizes an experiment that observed a weak gravitational shielding effect using a composite YBa2Cu3O7-x superconductor disk below 70K. When the disk was levitated and rotated at speeds up to 5000 rpm using electromagnetic fields, samples placed above it showed weight losses of up to 0.5% in stationary conditions and up to 2.1% at maximum rotation. Several checks were performed to rule out non-gravitational sources of error, providing evidence that a gravitational effect was observed.
Model Analysis of Cymbal Generator Under Different Working ConditionsIJRES Journal
In order to study the influence for natural frequency under different constraint conditions of Cymbal transducer. Through the use of ANSYS and SIMULATION with finite element method, the Cymbal transducer can be applied on different constraints and load conditions, calculation and analysis to obtain the modal under the specific natural frequencies and mode shapes. Which in the free and non free conditions yield stress limits are in the security domain, the modal analysis results of vibration mode and natural frequency shows that suitable for large load under low frequency vibration of train vibration load, the load in order to study, under low frequency vibration Cymbal transducer can provide simulation support for energy recovery applications.
Characterization of expanded austenite in stainless steels by ion carburizati...Javier García Molleja
Thesis dissertation in order to obtain the degree in Doctor in Physics. Austenitici stainless steel modification by ion carburization and study of its stability under plasma focus irradiation. Developed at Universidad Nacional de Rosario (Argentina) in March 2012
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
Model Analysis of Cymbal Generator Under Different Working ConditionsIJRES Journal
In order to study the influence for natural frequency under different constraint conditions of Cymbal transducer. Through the use of ANSYS and SIMULATION with finite element method, the Cymbal transducer can be applied on different constraints and load conditions, calculation and analysis to obtain the modal under the specific natural frequencies and mode shapes. Which in the free and non free conditions yield stress limits are in the security domain, the modal analysis results of vibration mode and natural frequency shows that suitable for large load under low frequency vibration of train vibration load, the load in order to study, under low frequency vibration Cymbal transducer can provide simulation support for energy recovery applications.
Characterization of expanded austenite in stainless steels by ion carburizati...Javier García Molleja
Thesis dissertation in order to obtain the degree in Doctor in Physics. Austenitici stainless steel modification by ion carburization and study of its stability under plasma focus irradiation. Developed at Universidad Nacional de Rosario (Argentina) in March 2012
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
IJRET-V1I2P1 -Measurement and FEMM Modelling of Experimentally Generated Stro...ISAR Publications
This work presents correlations between experimentally generated magnetic field strengths and computationally modeled field strengths. The experimental set-up comprised a C-shape structure designed to generate strong magnetic field strengths. The sections of the C-structure were individual solenoids made from copper-wound low carbon steel. These sections were connected such that the overall structure formed a continuous conduit for the magnetic flux and concentrated the magnetic field into an air gap. This experimental set-up could be used for magnetic annealing, or alternatively to measure the magnetostrictive strain properties of suitable materials, placed in the air gap. Magnetic field strengths of approximately 1.0 Tesla (T) were measured using a magnetic field strength meter. Finite Element Method Magnetics (FEMM) computational modeling software was used to model the design and predict field strengths. Modeled field strengths fell short of practical measurements. The efficiency of the apparatus in producing high fields is reduced due to effects related to drilling and machining of the steel core. Other reasons for discrepancies include the configuration of the C-shape, the properties of the core material, and skin effects. By building these considerations into the FEMM model, a more accurate representation of the workings of the C-shape set-up was achieved.
Study of Boron Based Superconductivity and Effect of High Temperature Cuprate...IOSR Journals
This paper illustrates the main normal and Boron superconducting state temperature properties of magnesium diboride, a substance known since early 1950's, but lately graded to be superconductive at a remarkably high critical temperature Tc=40K for a binary synthesis. What makes MgB2 so special? Its high Tc, simple crystal construction, large coherence lengths, high serious current densities and fields, lucidity of surface boundaries to current promises that MgB2 will be a good material for both large scale applications and electronic devices. Throughout the last seven month, MgB2 has been fabricated in various shape, bulk, single crystals, thin films, ribbons and wires. The largest critical current densities >10MA/cm2 and critical fields 40T are achieved for thin films. The anisotropy attribution inferred from upper critical field measurements is still to be resolved, a wide range of values being reported, γ = 1.2 ÷ 9. Also there is no consensus about the existence of a single anisotropic or double energy cavity. One central issue is whether or not MgB2 represents a new class of superconductors, being the tip of an iceberg that waits to be discovered. Until now MgB2 holds the record of the highest Tc among simple binary synthesis. However, the discovery of superconductivity in MgB2 revived the interest in non-oxides and initiated a search for superconductivity in related materials, several synthesis being already announced to become superconductive: TaB2, BeB2.75, C-S composites, and the elemental B under pressure.
Amorphous-nano-crystalline silicon composite thin films (a-nc-Si:H) samples were synthesized by
Plasma Enhanced Chemical Vapor Deposition technique. The measurement of DC conductivities was
accomplished using Dielectric spectroscopy (Impedance Spectroscopy) in wide frequency and temperature range.
In analysis of impedance data, two approaches were tested: the Debye type equivalent circuit with two parallel R
and CPEs (constant phase elements) and modified one, with tree parallel R and CPEs including crystal grain
boundary effects. It was found that the later better fits to experimental results properly describes crystal grains
dielectric effect and hydrogen concentration indicating presence of strain. The amorphous matrix showed larger
resistance and lower capacity than nano-crystal phase. Also it was found that composite silicon thin film cannot
be properly described by equivalent circuit only with resistors and constant phase elements in serial relation
Electrical Properties of Thermally Evaporated In40 Se60 Thin Filmsiosrjce
In40 Se60 thin films with different thicknesses (300,500, and 700nm) have been deposited by single
source vacuum thermal evaporation onto glass substrates at ambient temperature to study the effect of thickness
and on its structural morphology, and electrical properties. AFM study revealed that microstructure parameters
such as crystallite size, and roughness found to depend upon deposition conditions. The DC conductivity of the
vacuum evaporated In40 Se60thin films was measured in the temperature range (293-473)K and was found to
increase on order of magnitude with increase of thickness. The plot of conductivity with reciprocal temperature
suggests, there are two activation energies Ea1and Ea2 for In40 Se60 for all thicknesses which decreases with
increasing thickness .Hall effect measurement showed that low thickness In40 Se60 film exhibit p-type
conductance whereas the film exhibit n-type towards the higher thickness. The electric carrier concentration
and mobility show opposite dependence upon thickness.
Sputtering of Ga-doped ZnO nanocoatings on silicon for piezoelectric transducersMariya Aleksandrova
This talk was delivered on the 8TH INTERNATIONAL SCIENTIFIC CONFERENCE “TechSys 2019” – ENGINEERING, TECHNOLOGIES AND SYSTEMS, Technical University of Sofia, Plovdiv Branch, 16-18 May 2019. The research is funded by BNSF’s grant KП06-Н27/1.
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
This to demonstrate the laser ablation of hard materials to form a thin film for optical sensors. The work was done at DIllard University , New Orleans LA by Professor Abdalla Darwish. any comment e-mail adarwish@bellsouth.net.
IJRET-V1I2P1 -Measurement and FEMM Modelling of Experimentally Generated Stro...ISAR Publications
This work presents correlations between experimentally generated magnetic field strengths and computationally modeled field strengths. The experimental set-up comprised a C-shape structure designed to generate strong magnetic field strengths. The sections of the C-structure were individual solenoids made from copper-wound low carbon steel. These sections were connected such that the overall structure formed a continuous conduit for the magnetic flux and concentrated the magnetic field into an air gap. This experimental set-up could be used for magnetic annealing, or alternatively to measure the magnetostrictive strain properties of suitable materials, placed in the air gap. Magnetic field strengths of approximately 1.0 Tesla (T) were measured using a magnetic field strength meter. Finite Element Method Magnetics (FEMM) computational modeling software was used to model the design and predict field strengths. Modeled field strengths fell short of practical measurements. The efficiency of the apparatus in producing high fields is reduced due to effects related to drilling and machining of the steel core. Other reasons for discrepancies include the configuration of the C-shape, the properties of the core material, and skin effects. By building these considerations into the FEMM model, a more accurate representation of the workings of the C-shape set-up was achieved.
Study of Boron Based Superconductivity and Effect of High Temperature Cuprate...IOSR Journals
This paper illustrates the main normal and Boron superconducting state temperature properties of magnesium diboride, a substance known since early 1950's, but lately graded to be superconductive at a remarkably high critical temperature Tc=40K for a binary synthesis. What makes MgB2 so special? Its high Tc, simple crystal construction, large coherence lengths, high serious current densities and fields, lucidity of surface boundaries to current promises that MgB2 will be a good material for both large scale applications and electronic devices. Throughout the last seven month, MgB2 has been fabricated in various shape, bulk, single crystals, thin films, ribbons and wires. The largest critical current densities >10MA/cm2 and critical fields 40T are achieved for thin films. The anisotropy attribution inferred from upper critical field measurements is still to be resolved, a wide range of values being reported, γ = 1.2 ÷ 9. Also there is no consensus about the existence of a single anisotropic or double energy cavity. One central issue is whether or not MgB2 represents a new class of superconductors, being the tip of an iceberg that waits to be discovered. Until now MgB2 holds the record of the highest Tc among simple binary synthesis. However, the discovery of superconductivity in MgB2 revived the interest in non-oxides and initiated a search for superconductivity in related materials, several synthesis being already announced to become superconductive: TaB2, BeB2.75, C-S composites, and the elemental B under pressure.
Amorphous-nano-crystalline silicon composite thin films (a-nc-Si:H) samples were synthesized by
Plasma Enhanced Chemical Vapor Deposition technique. The measurement of DC conductivities was
accomplished using Dielectric spectroscopy (Impedance Spectroscopy) in wide frequency and temperature range.
In analysis of impedance data, two approaches were tested: the Debye type equivalent circuit with two parallel R
and CPEs (constant phase elements) and modified one, with tree parallel R and CPEs including crystal grain
boundary effects. It was found that the later better fits to experimental results properly describes crystal grains
dielectric effect and hydrogen concentration indicating presence of strain. The amorphous matrix showed larger
resistance and lower capacity than nano-crystal phase. Also it was found that composite silicon thin film cannot
be properly described by equivalent circuit only with resistors and constant phase elements in serial relation
Electrical Properties of Thermally Evaporated In40 Se60 Thin Filmsiosrjce
In40 Se60 thin films with different thicknesses (300,500, and 700nm) have been deposited by single
source vacuum thermal evaporation onto glass substrates at ambient temperature to study the effect of thickness
and on its structural morphology, and electrical properties. AFM study revealed that microstructure parameters
such as crystallite size, and roughness found to depend upon deposition conditions. The DC conductivity of the
vacuum evaporated In40 Se60thin films was measured in the temperature range (293-473)K and was found to
increase on order of magnitude with increase of thickness. The plot of conductivity with reciprocal temperature
suggests, there are two activation energies Ea1and Ea2 for In40 Se60 for all thicknesses which decreases with
increasing thickness .Hall effect measurement showed that low thickness In40 Se60 film exhibit p-type
conductance whereas the film exhibit n-type towards the higher thickness. The electric carrier concentration
and mobility show opposite dependence upon thickness.
Sputtering of Ga-doped ZnO nanocoatings on silicon for piezoelectric transducersMariya Aleksandrova
This talk was delivered on the 8TH INTERNATIONAL SCIENTIFIC CONFERENCE “TechSys 2019” – ENGINEERING, TECHNOLOGIES AND SYSTEMS, Technical University of Sofia, Plovdiv Branch, 16-18 May 2019. The research is funded by BNSF’s grant KП06-Н27/1.
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
This to demonstrate the laser ablation of hard materials to form a thin film for optical sensors. The work was done at DIllard University , New Orleans LA by Professor Abdalla Darwish. any comment e-mail adarwish@bellsouth.net.
ANTOINE GAZDA INVENTOR AND OF THE OERLIKON 20 MM AUTO CANNON THAT SAVED MANY SHIPS
N VIENNA I GOT TO SEE THE HOUSE AND HIS WORK SHOP, AND RECENTLY I GOT CONTACTED BY THE OWNER OF THE HOUSE IN RHODE ISLAND IN 2014 THAT WHERE ANTOINE GAZDA LIVED PLEASE GOOGLE SEARCH ANTOINE GAZDA
earthquake detection and x energy oil detection and hutchison effect John Hutchison
george former partner with me along with alik developed the feild stress detector of alex pezaro my other business partner
alex feild stress detector used vacuum tubes and it was known for many decades the new field stress detector was or is a power cell used in reverse george myself and alik we had fun with old germanium diodes with a small meter we would read field stress with buildings , different areas would show variations in microvolts voltage, polarity changing , and energy used with a computer George lisacaze and alik explored ideas in finding earthquakes oil
my company was Axiom General Systems in Canada recognized by the USA DOD SBIR PROGRAM George my self alik and Boeing's Eron Kovacks who funded us we had fun in detection od stuff we had a falling out Big court stuff we went our different ways
George used the technology in detection of the Hutchison effect i gave the technology to Roland Bredow in Germany WHO confirmed the Feild Stress Detector with help of Max Plant ct Alik has his unit TO THIS DAY
in short all one needs is a diode and a computer program and reference points or just a digital meter and a diode germanium type and others
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
1. arXiv:cond-mat/9701074v3[cond-mat.supr-con]16Sep1997
Weak gravitation shielding properties of
composite bulk Y Ba2Cu3O7−x superconductor
below 70 K under e.m. field.
E.E. Podkletnov
Moscow Chemical Scientific Research Centre
113452 Moscow - Russia
Abstract
A high-temperature Y Ba2Cu3O7−x bulk ceramic superconductor with composite struc-
ture has revealed weak shielding properties against gravitational force while in a levitating
state at temperatures below 70 K. A toroidal disk with an outer diameter of 275 mm and
a thickness of 10 mm was prepared using conventional ceramic technology in combination
with melt-texture growth. Two solenoids were placed around the disk in order to initiate
the current inside it and to rotate the disk about its central axis. Samples placed over the
rotating disk initially demonstrated a weight loss of 0.3-0.5%. When the rotation speed
was slowly reduced by changing the current in the solenoids, the shielding effect became
considerably higher and reached 1.9-2.1% at maximum.
74.72.-h High-Tc cuprates.
1 Introduction.
The behavior of high-Tc ceramic superconductors under high-frequency magnetic fields is of
great interest for practical applications. Crystal structure seems to be the key factor determin-
ing all physical properties of bulk superconductors, and the interaction of this structure with
2. external and internal e.m. fields might result in quite unusual effects. Despite a large number
of studies [1, 2, 3] the nature of these interactions still remains unresolved.
Our recent experimental work [4] clearly indicated that under certain conditions single-phase
bulk, dense Y Ba2Cu3O7−x revealed a moderate shielding effect against gravitational force. In
order to obtain more information about this unusual phenomenon, a new installation was built,
enabling operation with larger disks (275 mm in diameter), in magnetic fields up to 2 T and
frequencies up to 108
Hz at temperatures from 40 to 70 K. A new experimental technique was
employed to modify the structure of the ceramic superconductor. All these efforts yielded a
larger value of the shielding effect (up to 0.5% in stationary conditions and to 2.1% for shorter
periods), providing good hopes for technological applications.
A gravitational shielding effect of this strength has never been previously observed, and its
implications present serious theoretical difficulties (see [11] for references and an analysis of
some hypotheses). Thus, great attention was devoted to the elimination of any possible source
of systematic errors or of spurious non-gravitational effects. The small disturbances due to air
flows pointed out by some authors [9, 10] were eliminated by weighing the samples in a closed
glass tube (see Section 4). The entire cryostat and the solenoids were enclosed in a stainless
steel box. But probably the best evidence for the true gravitational nature of the effect is that
the observed weight reductions (in %) were independent of the mass or chemical composition
of the tested samples (Section 6).
This work is organized as follows. Sections 2 and 3 describe our experimental setup. Section
2 summarizes the main steps in the sinterization of the composite ceramic disk and contains
information about the final properties of the disk (Tc for the two layers, Jc for the upper layer,
etc.) and about the microscopic structure of the material. Section 3 describes how we obtain
and control the levitation and rotation of the disk, up to an angular speed of about 5000 rpm.
In Section 4 we describe the weight measurement procedure and analyze in detail possible
error sources and parasitic effects. Several checks were performed to exclude any influence of
spurious factors (Section 5). In Section 6 we give the maximum % shielding values obtained
in dependence on the rotation speed of the disk and on the frequency of the applied magnetic
field. Finally, Sections 7 and 8 contain a short discussion and our conclusions.
According to public information, a NASA group in Huntsville, Alabama, is now attempting
to replicate our experiment. This is a difficult task, especially in view of the sophisticated
2
3. technology involved in the construction of the large ceramic disk and in the control of its
rotation. We are also aware, through unofficial channels, that other groups are working on
similar experiments with smaller disks.
2 Construction of the disk.
The shielding superconducting element was made of dense, bulk, almost single-phase Y BCO
and had the shape of a toroidal disk with an outer diameter of 275 mm, an inner diameter of
80 mm, and a thickness of 10 mm. The preparation of the 123-compound and fabrication of
the disk involved mixing the initial oxides, then calcining the powder at 9300
C in air, grinding,
pressing the disk at 120 MPa, and sintering it in oxygen at 9300
C for 12 hours with slow
cooling to room temperature. After that, the disk was put back in the furnace at 6000
C,
and the upper surface was quickly heated to 12000
C using a planar high-frequency inductor
as shown in Figure 1. During this last heating, the gap between the disk and the inductor
was chosen precisely so that heating would occur only in the top 2 mm-thick layer of the
disk, although the material’s high heat conductivity caused some heating below this region.
Finally, the disk was slowly cooled down to room temperature in a flow of oxygen and treated
mechanically in order to obtain good balance during rotation. A thin (1 mm) foil of magnetic
material was attached (without electric contact) to the upper surface of the disk, using hot-melt
adhesive, to facilitate rotating the disk as described below, especially at the initial stages of
rotation.
The phase and crystal structure of the superconductor were studied using X-ray diffraction
analysis (XRD) and a scanning electron microscope (SEM) equipped with an energy dispersive
spectral (EDS) analyzer. The samples were cut layer by layer from the bulk ceramic disk.
The analysis of the cross-section of the ceramic Y Ba2Cu3O7−x disk revealed the existence
of two zones with different crystal structures. The upper part of the disk (6-7 mm thick) had
an orthorhombic structure typical of the quench and melt growth process [5, 6] and consisted
mainly of single-phase orthorhombic 123-compound. This material was dense, with uniformly
fine grain boundaries, i.e. no impurities or secondary phases were found between the grains.
Inter-grain boundaries were barely visible, indicating that there were good electrical contacts
between the particles of the superconducting body and that the sintering of the material had
3
4. produced a nearly perfect polycrystal lattice with no apparent defects.
The grains were less than 2 µm wide and were oriented (about 75%) with c-axis parallel to
the surface of the disk. The transition temperature Tc for this region of the disk was found by
direct measurements to be 94 K, with a width of 1.5-2 K. Tc was determined from the resistive
transition in a variable temperature cryostat, under zero magnetic field, using an AC current
and sputtered golden contacts.
The lower part of the disk, which was in contact with a water-cooled base during the high-
frequency heat treatment, had a markedly different structure: randomly oriented grains, with
typical grain sizes between 5 and 15 µm. The porosity of this zone varied from 5 to 9% and
the material contained about 40% of the tetragonal phase. The transition temperature Tc was
equal to 60 K, with a width of ca. 10 K. EDS analysis showed the presence of small inclusions
of Y2BaCuO5 in the lower layer.
Crystal lattice parameters for these two layers, as calculated from XRD, are listed below.
These are dimensions in nm:
Upper layer: a=0.381; b=0.387; c=1.165;
Lower layer: a=0.384; b=0.388; c=1.170 (orthorhombic phase);
a=0.387; c=1.183 (tetragonal phase).
The critical current density was measured for samples cut from the top of the supercon-
ducting disk. Measurements of Jc were carried out at 75 K using an AC current, four-probe
method, and direct transport measurements. The accuracy for Jc determination was defined
as 1 µV/cm in a zero magnetic field, with the sample immersed in liquid nitrogen. It turned
out that Jc exceeded 15000 A/cm2
. The value of JC for the lower part of the disk was not
measured, since it is not superconducting at the temperature of operation.
We also estimated the current density in the upper part of the disk while subjected to the
magnetic fields usually applied during the measurements. To measure this we made a thin
radial cut through the sample disk and attached electric contacts to an ampermeter, with a
tecnique allowing fast on/off switching. We calibrated the currents in the driving coils that
correspond to the currents inside the disk. These currents are slightly different for each new
disk as the thickness of the SC part is not the same in every new sintered ceramic toroid, but
we estimate their density to range between 5000 and 7000 A/cm2
.
4
5. 3 Operation of the apparatus.
Two identical solenoids were placed around the superconductor using fibreglass supports, as
shown in Figures 2, 4, 5. The gaps between these solenoids and the disk were large enough for
it to move about 20 mm in any lateral direction. The toroidal disk was placed inside a cryostat
equipped with a set of three coils (Fig. 3) that could keep it levitating when it reached the
superconducting state. The angle β was between 5 and 15 degrees. This helped to keep the
rotating disk in a stable position, otherwise it tended to slip aside.
A schematic of the electrical connections is shown in Fig. 6. High-frequency electric current
(105
Hz) was first sent to the two main solenoids around the disk to initiate an internal current
in the ceramics while the disk was still at room temperature. Then the system was slowly
cooled down to 100 K by liquid nitrogen, and then quickly cooled by liquid helium vapors. We
estimate the temperature of the disk to be lower than 70 K in stationary conditions. Thus the
upper layer of the disk is superconducting in these conditions, while the lower layer is not. The
main solenoids were switched off. After this, the high-frequency current was sent to the coils
below the disk, and the superconductor raised up (at least 15 mm; see Section 6).
Then a small current (105
Hz) was sent to the main solenoids, causing the disk to begin
rotating counter-clockwise with increasing speed. The rotation speed was increased up to 5000
rpm. At this point the current in the rotating coils was of the order of 8-10 A. (The diameter
of the wire of these coils is 1.2 mm). This current was supplied by powerful high-frequency
generators usually employed for induction heating and quenching of metals.
Most weight measurements for various objects were taken in these conditions, which can
be maintained in a stable way for quite long periods (10 minutes or more). Next, the disk’s
rotational speed was slowly reduced by changing the current in the main solenoids (Fig. 9).
The speed of rotation was regulated by means of laser beam reflections off a small piece of
plastic light-reflecting foil attached to the disk.
The frequency of the e.m. field was varied from 103
to 108
Hz. Samples made of various
materials were tested, including metals, glass, plastic, wood and so on. All the samples were
hung over the cryostat on a cotton thread connected to a sensitive balance. The distance
between the samples and the cryostat varied from 25 to 3000 mm.
5
6. 4 Weight measurements. Error sources.
To measure the weight loss of the samples, we used a Dupont balance that is a part of the
standard equipment for DTA and TGA (differential thermal analysis, thermo-gravimetric anal-
ysis). One of the two arms of the balance, holding the sample to be weighed, was lying within
the vertical projection of the HTC disk (we call this region the ”shielding cylinder”), while the
other arm was well outside. The arms of the balance were up to 220 cm long. The sensitivity
of the balance for masses of 10-50 g, like those employed in the measurements, is on the order
of 10−6
g, which was sufficient to detect the observed weight loss. Three different balances were
used for verification and are described below (see ”Checks”, Section 5).
The main error sources in the weight measurements were the following.
1. Buoyancy and air flow. The presence of the cryostat perturbs the air and causes weak
local flows. Moreover, a much larger ascending flux is caused by the weight loss of the air
in all the shielding cylinder; this also produces a pressure drop in the shielding cylinder
(see Section 6). The error introduced by this effect in the weight measurements has been
substantially reduced by enclosing the samples to be weighed in a long glass tube, closed
at the bottom. The samples had the form of elongated objects (like big pencils). In order
to set an upper limit on the buoyancy effect, some flat samples were weighed too, without
enclosing them in the glass tube, in vertical and horizontal positions, and the results for
the two cases were compared. It turned out that the weight loss in horizontal position
was larger (by approx. 10% of the total loss) than in vertical position.
2. Hydrostatic force. This introduces a slight dependence of the weight loss on the density
of the sample. For a material with density 1 Kg/dm3
, the Archimede pull amounts to
about the 0.1% of the weight. Since the air density is slightly lower in the shielding
cylinder (see above and Section 6), the Archimede pull is lower itself, but this effect can
be disregarded, being of the order of 0.001% of the total weight or less.
3. Diamagnetism. It is known that molecular diamagnetism produces a small levitating force
on samples placed in a magnetic field gradient. For a large class of materials, this force is
essentially independent on the chemical composition of the material and is proportional
to its weight. For instance, a standard value for the diamagnetic levitating force is the
6
7. following: in a field gradient of 0.17 T/cm the force exerted on a 1 g sample of NaCl,
SiO2, S or diamond is ca. equal to 16 dyne (about 0.016 g, or 1.6% of the weight).
Since the force is proportional to the square of the field gradient, one easily finds that the
value of the field gradient corresponding to a percentage weight loss of 0.1% is about 0.04
T/cm (for comparison, we recall that the maximum weight loss we observed in stationary
conditions was 0.5%). A mapping of the static field produced by our apparatus yelded in
all cases smaller values of the field gradient near the disk, and much smaller values at a
height of 50 cm or more above the disk, where the observed weight loss stays the same
(compare Section 6). We thus conclude that the effect of molecular diamagnetism can be
completely disregarded.
4. RF fields. The possibility of a slight levitating effect from an RF magnetic field cannot
be excluded completely. However, such disturbance was attenuated, if not eliminated, by
placing thick metal screens between the cryostat and the samples. Copper, aluminum, and
steel screens were tested separately and in many different combinations. The individual
screens had a diameter of 300 mm and a thickness of 50 mm. The presence of the screens
never altered the effect.
5 Checks.
We did several checks in order to correlate more clearly the appearence of the effect to specific
experimental conditions.
1. Substituting a metal disk or a disk made totally from superconducting ceramic. In all
these cases, the shielding effect was not observed. This confirms, in our opinion, that the
origin of the effect resides in the interaction between the upper (superconducting) part
of the disk and the lower part, where considerable resistive phenomena take place.
2. Measurements in vacuum, or in different gases, or in a fluid. These measurements show
that the effect exists in these conditions, too, and has the same magnitude as in air. For
these cases, however, we cannot furnish data as precise as the measurements taken in air
yet, because the experimental conditions are more difficult and the necessary statistics
7
8. are still being accumulated. Measurements in vacuum or in gases other than air (N2, Ar)
are hampered by the fact that the samples and the analytical balance must be enclosed
in a sealed container. For the measurements in fluids (H2O, C2H5OH) Archimede pull is
more relevant and thus complicates measurements.
3. An AC field is indispensable. The shielding effect was completely absent when only static
magnetic fields were employed.
4. Other weighing techniques. Although the most accurate measurements have been taken
with the Dupont balance for precision differential thermogravimetric analysis, we em-
ployed for verification three other balances. In the latest runs, using heavier samples with
weights varying from 100 g to 250 g, a standard analytical balance was used. Given these
masses and the balance’s accuracy (0.01 g), weight losses of 0.01% were easy to detect.
In addition, we used two other types of balances, sketched in Fig. 8. The first one is
a torsion balance, whose oscillation period depends on the tension of the wire and thus
on the weight of a suspended sample. This period can be measured with high accuracy
through a laser beam reflected by a mirror attached to the wire. Finally, we employed a
spring balance whose movements are detected by an induction transducer.
6 Results.
The levitating disk revealed a clearly measurable shielding effect against the gravitational force
even without rotation. In this situation, the weight-loss values for various samples ranged from
0.05 to 0.07%. As soon as the main solenoids were switched on and the disk began to rotate
in the vapors of liquid helium, the shielding effect increased, and at 5000 rpm, the air over the
cryostat began to rise slowly toward the ceiling. Particles of dust and smoke in the air made
the effect clearly visible. The boundaries of the flow could be seen clearly and corresponded
exactly to the shape of the toroid.
The weight of various samples decreased no matter what they were made from. Samples
made from the same material and of comparable size, but with different masses, lost the same
fraction of their weight. The best measurement gave a weight loss of 0.5% while the disk was
spinning at 5000 rpm, with typical values ranging from 0.3 to 0.5%. Samples placed above the
8
9. inner edge of the toroid (5-7 mm from the edge) were least affected, losing only 0.1 to 0.25%
of their weight. The external boundary of the shielding cylinder was quite clear (no more than
2 cm). The maximum values of weight loss were obtained when the levitation height of the
disk was at its maximum value, about 30-35 mm over the magnets. This condition cannot be
reached above 70 K, although the disk had become superconducting already at 94 K.
During the time when the rotation speed was being decreased from 5000 to 3500 rpm, using
the solenoids as braking tools, the shielding effect reached maximum values: the weight loss
of the samples was from 1.9 to 2.1%, depending on the position of the sample with respect to
the outer edge of the disk. These peak values were measured during a 25-30 seconds interval,
when the rotational speed was decreasing to 3300 rpm. Because of considerable disk vibration
at 3000-3300 rpm, the disk had to be rapidly braked in order to avoid unbalanced rotation,
and further weight measurements could not be carried out.
The samples’ maximum weight loss was observed only when the magnetic field was operating
at high frequencies, on the order of 3.2 to 3.8 MHz. The following tables show how the shielding
effect varied in response to changes in the disk’s rotation speed or the current frequency.
9
10. At constant frequency of 2 MHz:
Rotation speed (rpm) Weight loss (%)
4000 0.17
4200 0.19
4400 0.20
4600 0.21
4800 0.22
5000 0.23
At constant rotation speed of 4300 rpm:
Frequency (MHz) Weight loss (%)
3.1 0.22
3.2 0.23
3.3 0.24
3.4 0.26
3.5 0.29
3.6 0.32
Remarkably, the effective weight loss was the same even when the samples, together with
the balance, were moved upward to a distance of 3 m, but still within the vertical projection
of the toroidal disk. No weight loss at all was observed below the cryostat.
We also observed a slight diminution of the air pressure inside the shielding cylinder. The
difference between the external and the internal pressure was up to 5 mm of mercury in sta-
tionary conditions (disk rotating at 4000-5000 rpm) and increased up to 8 mm of mercury
during the ”braking” phase. Pressures were measured through a vacuum chamber barometer.
We believe that the diminution of the pressure inside the shielding cylinder is originated by
the pseudo-convective motion of the air, which being lighter tends to raise. This phenomenon
is favoured by the fact that an entire cylinder of air get lighter at the same time and thus the
ascending motion is amplified.
10
11. 7 Discussion.
The interaction of a superconducting ceramic body with the gravitational field is a complicated
process and cannot be characterized by one single law or physical phenomenon. Also, a compre-
hensive explanation of the mechanism responsible for high-temperature superconductivity has
not yet been found. Still, these facts do not make the observed phenomenon less interesting.
In our previous work [4] the weight loss of samples over the levitating superconductor was
smaller, varying from 0.05 to 0.3%. At that time it was difficult to exclude entirely any influence
from the radio-frequency field because the sample was separated from the disk and the magnets
by a thin plastic film. Now, the superconductor is situated in a stainless steel cryostat, so this
influence should be negligible (see also Section 5).
The modification of the superconductor’s crystalline structure produced a composite body
with a dense and highly oriented upper layer and a porous lower layer with random grain
orientation. The upper layer is superconducting at the operation temperature and is able to
carry high Jc current under considerable magnetic field, while the lower layer cannot conduct
high currents. The boundary between the two layers is likely to constitute a ”transition” region
in which the supercurrents, that are completely free to move in the upper layer, begin to feel
some resistance.
It is also expected that a complex interaction between the composite ceramic body and
the external magnetic field takes place. This interaction depends on the coherence length, the
flux pinning, the field frequency and the field force, the penetration depth, and the parameters
of the crystal lattice. These characteristics are interrelated in a complex way. According to
the experimental data (compare also [10], where only a static field was applied), a levitating
superconductor does not reveal any unusual shielding if it has no contact with the high frequency
AC magnetic field.
As analyzed in [7, 8], pinning centers with different origins may exist inside the supercon-
ducting disk, and fluxes will be trapped at some of them. Fluxes trapped at weak centers will
begin to move first, while those trapped at strong centers will not move until the Lorentz force
exceeds the pinning force. The overall current will be composed of the superposition of flux
motions with different speeds.
There are no grounds to claim that the rotation momentum of the disk interacts with
11
12. gravitation force, but it seems that fast rotation is favorable for stabilization of the shielding
effect.
Finally, it is worth noting that the experimental equipment described above has much in
common with magneto-hydro-dynamic (MHD) generators.
The first attempt at a theoretical explanation of the effect has been offered by G. Modanese
[11, 12]. Further investigations now in progress may help to prove, change, or complete the
present understanding of the observed phenomenon.
8 Conclusions.
A levitating superconducting ceramic disk of Y Ba2Cu3O7−x with composite structure demon-
strated a stable and clearly measurable weak shielding effect against gravitational force, but
only below 70 K and under high-frequency e.m. field. The combination of a high-frequency
current inside the rotating toroidal disk and an external high-frequency magnetic field, together
with electronic pairing state and superconducting crystal lattice structure, apparently changed
the interaction of the solid body with the gravitational field. This resulted in the ability of the
superconductor to attenuate the energy of the gravitational force and yielded a weight loss in
various samples of as much as 2.1%.
Samples made of metals, plastic, ceramic, wood, etc. were situated over the disk, and
their weight was measured with high precision. All the samples showed the same partial loss
of weight, no matter what material they were made of. Obtaining the maximum weight loss
required that the samples be oriented with their flat surface parallel to the surface of the disk.
The overall maximum shielding effect (2.1%) was obtained when the disk’s rotational speed
and the corresponding centrifugal force were slightly decreased by the magnetic field.
It was found that the shielding effect depended on the temperature, the rotation speed,
the frequency and the intensity of the magnetic field. At present it seems early to discuss the
mechanisms or to offer a detailed analysis of the observed phenomenon, as further investiga-
tion is necessary. The experimentally obtained shielding values may eventually prove to have
fundamental importance for technological applications as well as scientific study.
12
13. 8.1 Acknowledgments.
The author is grateful to the Institute for High Temperatures at the Russian Academy of
Sciences for their help in preparing the unique superconducting ceramic disks and for being
permitted to use their laboratory equipment. The effect was first observed and studied at
Tampere University of Technology. The author would like to thank G. Modanese, F. Pavese
and O. Port for advice and support.
References
[1] Riise A.B., Johansen T.H., Bratsberg H. and Yang Z.J., Appl. Phys. Lett. 60 (1992) 2294.
[2] Brand E.H., Am. J. Phys. 58 (1990) 43.
[3] Lofland S., Huang M.X. and Bhagat S.M., Physica C 203 (1992) 271.
[4] Podkletnov E. and Nieminen R., Physica C 203 (1992) 441.
[5] Murakami M., Morita M., Doi K., Miyamoto K. and Hamada H., Jpn. J. Appl. Phys. 28
(1989) 399.
[6] Murakami M., Morita M. and Koyama N., Jpn. J. Appl. Phys. 28 (1989) 1125.
[7] Takizawa T., Kanbara K., Morita M. and Hashimoto M., Jpn. J. Appl. Phys. 32 (1993)
774.
[8] Xu J.H., Miller J.H. Jr. and C.S. Ting, Phys. Rev. B 51 (1995) 424.
[9] Bull M., De Podesta M., Physica C 253 (1995) 199.
[10] Unnikrishnan, C.S., Physica C 266 (1996) 133.
[11] Modanese G., Europhys. Lett. 35 (1996) 413.
[12] Modanese G., Phys. Rev. D 54 (1996) 5002; Modanese G. and Schnurer J., Possible
quantum gravity effects in a charged Bose condensate under variable e.m. field, report
UTF-391/96, November 1996, Los Alamos database nr. gr-qc/9612022.
13
14. FIGURE CAPTIONS.
1. Schematic cross-section of the furnace for high-temperature treatment of the ceramic disk
with planar hig-frequency inductors.
2. General magnets and cryostat setup.
3. Typical geometry and position of the disk over supporting solenoids.
4. Schematic design of rotating solenoids. a, b: various configurations.
5. Typical configuration of the tested set-up for the rotating solenoids.
6. Block scheme of the electrical connections.
7. Schematic design of the cryogenic system for the refrigeration of the superconducting
disk.
8. General configuration of the equipment for the weight loss measurements.
9. Typical design of the three-point disk-braking system.
14
15. High T materials, fabrication
stabilized
zirkonia
superconductor
|general, fig. 21/3|c
O2 O2
O2
O2
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Fig. 1
20. rotating solenoids
supporting solenoids
braking system
fuses
fuses
h.f. generator
h.f. generator
Ac regulator
Ac regulator
Ac regulator
power supply
power supply
Electric circuits |general, fig. 41/3|
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Fig. 6
21. electric cables
inlet - outlet
optical
fibers
liquid nitrogen
inlet - outlet
liquid helium
inlet - outlet
to atmosphere and
to rotary pump
rubber
o - ring
thermocouples as
gas level meter
|general, fig. 51/5|Cryogenic system
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Fig. 7
22. sample
glass cylinder
balance
projection
of the disk
sensor
solenoid
mirror
light
source
|general, fig. 61/4|Weight & pressure measurements
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Fig. 8
23. |general, fig. 71/3|Disk braking system
Created using Super. Tech. Top Draw 1/25/97 7:37:17 PM
Fig. 9