bluuebunny/crossref_metadata_2025 huggingface dataset:
IDENTIFICATION OF LAND COVER CHANGESFROM LANDSAT 8 OLI SATELLITE IMAGERY USING NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI) METHOD (STUDY CASE: SURABAYA)
Authors: Yusroni Syafira Alif , Kemalasari Vahira Tri , Putra Dhea Pratama Novian
Published: February 2023

Changes in land use in an urban area, such as Surabaya have a major influence on the balance of nature and the environment of its people. Analysis related to changes in land use from time to time is important to maintain the dynamics of development in Surabaya. The land use identification method in this study utilizes the Normalized Difference Vegetation Index (NDVI) to identify the effect of differences in the spectrum due to vegetation and non-vegetation. Satellite image data is analysed based on the spectrum and the results of the land cover classification have been obtained. From six classes of land cover classification results, it was found that the largest decreasing trend in the area was in class 6, one of which contained urban forest around 13% to 9%. For the trend of increasing area, the largest area occurs in class 5, which includes a land cover of undeveloped land which has the potential for building and infrastructure construction to be carried out around 15% to 19%. Surabaya has a development pattern on the use of vacant land for public and private facilities, which has the potential to reduce the area of an urban forest. Given that the function of forests in urban areas is quite necessary for the stability of air temperature and maintaining the beauty of the city.
SELECTION OF DECOMMISSIONING METHODS FOR GAS PLANT FACILITIES USINGANALYTICAL NETWORK PROCESS
Authors: Prayudha Aditya , Buda Artana Ketut , Pratiwi Emmy , C Katon Yoke , Agung P Achmad
Published: February 2023

The high complexity of decommissioning decisions presents a challenging problem for decision-makers due to the various parameters and stakeholders involved. Currently, a Floating Production Unit, BW Joko Tole located at the Lapangan Terang Sirasun Batur field, in East Madura Waters are expected to be decommissioned as gas reserves are running low for the upcoming 9 years. Multi-Criteria Decision Analysis has begun to be implemented by several oil and gas companies and several studies applied various MCDA methods in choosing the best alternatives. Analytical Network Process is a powerful tool to handle the interdependencies of elements involved in decommissioning, as no other MCDA methods can accommodate these relationships between elements. This study aims to simulate the implementation of the Analytical Network Process as one of MCDA methods in choosing decommissioning methods for these facilities, specifically pipelines and umbilicals operated by FPU BW Joko Tole. Regulatory review is carried out to determine the suitable alternatives, criteria, and sub-criteria needed to be considered in choosing decommissioning alternatives and evaluated using the Analytical Network Process (ANP). This study will provide an example of the ANP network model in decommissioning decisions followed by a sensitivity analysis to determine the robustness of the chosen alternatives and the values of each element involved.
ANALYSIS OF FLOOD DISASTER AREAS, JOMBANG REGENCY, EAST JAVA USING ARCGIS REMOTE SENSING
Authors: Iswandaru Yoga Satria Iswandaru , Widodo Amien , Singgih Purwanto Moh.
Published: February 2023

Flood is one of the natural disasters that occur in Indonesia. Each region in Indonesia has a different flood hazard level. Therefore, a study was conducted to map the level of flood hazard in Jombang Regency, East Java. Remote sensing methods are used to map flood-prone areas, ArcMap software is used to map disaster-prone areas and mapping vegetation density. The data required is in the form of flood data index from Inarisk and Landsat 8 imagery data from USGS. From these data, four maps were generated, namely the vegetation density map and the flood hazard map in the Jombang area. From the vegetation density map, it can be seen from the value it determines the level of vegetation density in the area, while the flood hazard map is categorized into three hazard categories, namely low, medium and high. And it was found that the lower the level of vegetation density, the higher the level of flood hazard in the area, and vice versa and it is also known that the Brantas river affects flooding in Jombang. Then seen from the regional geology, the area of North Jombang absorbs air more quickly because it is composed of karst rocks. Judging from the area of the flood hazard level, the Jombang area is more dominant to the moderate hazard level.
STEP FORWARD FOR CFD UNCERTAINTY ANALYSIS OF SHIP RESISTANCE BENCHMARK MODEL LHI-007
Authors: Rina Rina , Purnamasari Dian , Dwi Yulfani Rosi , Johar Alif Rahadi Shinta
Published: February 2023

Computational Fluid Dynamics (CFD) is a tool for solving the basic problems of equations for model flow motion. The CFD application can be used to predict the magnitude of the ship's resistance which is related to the engine power needed to move the ship. Benchmarking is the process of comparing different methods, procedures, and physical models to provide a common basis for the validation of numerical methods. This study simulates the resistance test on the LHI 007 benchmark ship model using FINE™/Marine with speed ranges 1.63 m/s – 2.47 m/s at a temperature of 27°C. The purpose of this research is to complete the simulation approach and numerical uncertainty for the previous study. By adding a time step component to the verification and validation of the uncertainty analysis, the error value gets smaller than the validation value for various speeds 1.63 m/s, 1.8 m/s, 1.91 m/s and 2.02 m/s. It shows that validation was achieved.
To explore the factors that impact on patient concordance with venous leg ulcer management using compression therapy
Authors: Barnes Helen
Published: February 2023

It is understood that intervention for venous leg ulcer (VLU) management is more successful the sooner compression is applied, yet healing rates of VLUs are falling and recurrence rates increasing. This literature review seeks to explore the factors affecting patient concordance with compression therapy to manage VLU. Of the literature searched, 14 articles were identified and four themes of reasons for non-concordance emerged: education; pain/discomfort; physical limitations; and psychosocial issues. The reasons for non-concordance are vast and complex; district nurses must explore these reasons to help improve the alarming rates of non-concordance. A personalised approach is necessary to meet individual needs. High risks of ulcer recurrence are noted and a greater understanding of the chronic nature of ulceration should be conveyed. Follow-up care and building trust is linked with higher rates of concordance. Further research is needed within district nursing as the majority of venous ulceration is managed within the community.
Can You Minimise Human Error? Yes.
Authors: Wilson Larry
Published: February 2023

By understanding the behavioural patterns around workplace accidents, the safety of your staff on site can be greatly improved
Employment Law SOS
Authors: Giltrap Laura
Published: February 2023

This month, our employment law specialist takes a look at hiring a member of staff - based on gender - to ‘get the numbers up’, temperature issues within the factory and a company worried that its reputation could be damaged after the founder and chairman is accused of historic crimes
Promotion Pressure
Authors: Beck Chris
Published: February 2023

Research has shown a disconnect between management and the rest of the workforce. The secret to this is better training and clearer lines of communication, says Jon Dean, MD of business performance training provider, Impeiius
The Future of Lean
Authors: Beck Chris
Published: February 2023

As automation and Industry 4.0 become increasingly mainstream, is there still a place for ‘traditional’ lean manufacturing methods?
Materials Handling – Keeping it Safe
Authors: McVicar Martin
Published: February 2023

Manufacturers need to ensure that their products are designed to allow the safest possible working environment for operators – and Combilift can help
Natural Frequency Measurement of Modest Dwelling Houses
Authors: Setiawan Bambang , Al-Huda Nafisah , Yulianur Alfiansyah , Abdullah Nora , Juellyan Juellyan , Permana Athalya Khanza , Sawitri Jihan Indria
Published: February 2023

Around 1000 to 4000 units of modest dwelling houses are annually built in Aceh Province. A modest dwelling house is a small type of house with limitations in space planning which is very suitable for small families with middle to lower incomes. This lower middle-class community is a group of people who are very vulnerable and will be very severely affected when a disaster occurs. A modest dwelling house is a one-story building with simple construction and structure in its physical form. On the other hand, Aceh is also one area that is very prone to earthquake disasters from along the subduction zone and Sumatran Fault. Therefore, measuring the frequency of a modest dwelling house is crucial to understanding all house elements' conditions. It is essential to estimate the integrity and safety of the house after an earthquake occurs. The method used in this research is using the field experiment method in the form of measuring the natural response of the building to vibration based on microtremor data. This study uses a seismometer. The data is stored in a data logger. The seismometer is placed on the floor of the house. Data collection is carried out when no major activities are around the house. Measurements were carried out for a minimum of 60 minutes. Computer analysis with specific parameters obtained using Geopsy software. The result of this study indicates that the dominant frequency of modest dwelling houses measured is around 2.99 Hz. The analysis results from the field experiment were validated using pushover analysis of the detailed engineering design data. The modeling results show that in the x-axis direction (parallel to the direction of the building), the frequency obtained is 7.14 Hz. Pushover analysis on the model with the y-axis direction (parallel to the side of the building) obtained a frequency of 7.46 Hz. This validation shows a huge difference between the frequency of field measurement results and computer modeling results. Many factors, including decreasing or degrading the concrete construction quality in the field, can cause this gap.
Ética de los sentimientos, desarrollo de capacidades, memoria histórica y reconciliación: la fragilidad del personal de salud en el conflicto armado colombiano
Authors: Bautista Espinel Gloria Omaira , Gonzalez Escobar Dianne Sofía , Díaz Monsalve Sonia , Bermúdez Bautista Ana María
Published: February 2023

Objetivo: analizar la forma en que los sentimientos y la recuperación de la memoria colectiva, posibilitan la disminución de la fragilidad social y política de los integrantes de la Misión Médica, haciendo factible nuevas maneras de participación, mediante el desarrollo de capacidades deliberativas desde la perspectiva bioética. Metodología: estudio exploratorio con enfoque cualitativo, que toma en cuenta la subjetividad e intersubjetividad de los participantes. Con fuentes de información heterogénea: grupos focales, entrevistas semiestructuradas y cartillas de campo, se constituyó un marco de factores relevantes, que permitieron procesar la información, mediante relaciones y categorizaciones conceptuales, para su posterior triangulación. Resultados: los sentimientos con mayor impacto ético en Misión Médica: incertidumbre, inseguridad ante el trabajo, ansiedad por los hechos de violencia, tristeza, temor, miedo e impotencia; producen efectos emocionales relacionados con el principio de maleficencia. La resiliencia, ha impedido realizar ejercicios de memoria colectiva, a causa del negacionismo y temor a recordar los hechos más significativos, esto les ha impedido el acceso a los mecanismos de Justicia Restaurativa. La ausencia de capacidades para afrontar la situación compromete la autonomía individual, la salud laboral y genera carencias legales no resueltas. Conclusiones: los sentimientos colectivos en el ámbito público del personal sanitario prevalecen sobre los sentimientos individuales basados en vivencias, que afectan la capacidad de deliberación, esto implica promover ejercicios de memoria colectiva, sobre los hechos del conflicto, mediante el desarrollo de capacidades que fortalezcan la legitima defensa de su autonomía y el desarrollo de un ejercicio profesional beneficiente, ante situaciones limítrofes de confrontación.
Aspectos éticos del servicio de telemedicina de una Mutua laboral
Authors: Ballesteros Polo Monica
Published: February 2023

MC Mutual es una Mutua Laboral que en 2021 inició un proyecto de telemedicina (TM), con el propósito de crear un modelo asistencial más sostenible y eficiente. Objetivo: Revisar los aspectos éticos y fortalezas del proyecto. Metodología: Revisión de la documentación existente en MC Mutual relativa a TM, entrevistas con el Director del proyecto y con dos profesionales del equipo de TM, sesión formativa y taller de simulación en el uso de la herramienta de TM. Resultados: Es un proyecto que desde su implementación contempló aspectos éticos esenciales: relación médico-paciente basada en un examen personal y conocimiento suficiente del historial médico del paciente, en la confianza y respeto mutuo; elaboración de consentimientos informados específicos; autonomía profesional para decidir el tipo de consulta más apropiado; disposición de los sistemas de telecomunicación con los requisitos necesarios; medidas de evaluación que preserven la calidad de la atención, seguridad del paciente, el mejor diagnóstico y prácticas de tratamiento posibles. Conclusiones: El proyecto de TM representa una oportunidad de mejora en la atención de los pacientes localizados en los centros asistenciales, haciendo que personal altamente capacitado esté disponible para pacientes y profesionales sanitarios que así lo requieran manteniendo condiciones óptimas de seguridad y calidad en la atención del paciente. Adicionalmente facilita el trabajo colaborativo entre profesionales sanitarios de centros asistenciales y centros de referencia.
Deformation prediction of functionally graded materials in laser directional energy deposition using forward-inverse calibration of the inherent strain in multi-scanning directions
Authors: Ye Chao , Chen Yun , Hou Liang , Xu Yang , Li Yuan , Guo Jing
Published: February 2023

This paper presents the study of the residual deformation of functional gradient materials (FGMs) constructed by laser directed energy deposition (L-DED) and proposes a forward and reverse framework for inherent strain calibration, considering the effect of scan directions. First, the inherent strain and the corresponding residual deformation in the scanning strategies with the 0°, 45°, and 90° directions are calculated from the multi-scale model of the forward process, respectively. Then the inherent strain is calibrated inversely using the pattern search method based on the residual deformation of experiments by L-DED. The final inherent strain calibrated in the direction of 0° can be achieved through the rotation matrix and averaging. Finally, the final calibrated inherent strain is applied to the model of the rotational scanning strategy. The predicted trend of the residual deformation is highly consistent with the experiments in the verification stage. This work can provide a reference for the prediction of the residual deformation of FGMs.
Wideband multiwavelength Brillouin fiber laser with switchable channel spacing
Authors: Shi Yang , Wang Ting , Hao You-Zeng , Bai Hua-Yu , Yang Yue-De , Xiao Jin-Long , Chen You-Ling , Huang Yong-Zhen
Published: February 2023

A multiwavelength Brillouin fiber laser (MBFL) with a switchable channel spacing is demonstrated using a 1.55-µm single-mode AlGaInAs/InP hybrid square–rectangular laser as a seeding source. The scheme employs a highly nonlinear fiber loop with a feedback path to generate a 10-GHz-spacing MBFL. Then, assisted by a tunable optical bandpass filter, MBFLs with spacing from 20 GHz to 100 GHz at a step of 10 GHz are generated in another highly nonlinear fiber loop based on the cavity-enhanced four-wave mixing. More than 60 lasing lines with an optical signal-to-noise ratio over 10 dB are obtained successfully in all the switchable spacings. The total output power and the channel spacing of the MBFLs are proved to be stable.
Spectral shaping of an ultrafast ytterbium fiber laser via a passive intracavity optical filter: a simple and reliable route to sub-45  fs pulses
Authors: Cooper Nicholas D. , Ta Uyen M. , Reber Melanie A. R.
Published: February 2023

We investigate the use of passive intracavity optical filters for
controlling the laser output spectrum of a polarization-mode-locked,
ultrafast ytterbium fiber laser. The overall lasing bandwidth is
increased or extended by strategic choice of the filter cutoff
frequency. Overall laser performance, including pulse compression and
intensity noise, is investigated for both shortpass and longpass
filters with a range of cutoff frequencies. The intracavity filter not
only shapes the output spectra, but also provides a route for overall
broader bandwidths and shorter pulses in ytterbium fiber lasers. These
results demonstrate that spectral shaping with a passive filter is a
useful tool to routinely achieve sub-45 fs pulse durations in
ytterbium fiber lasers.
Applications of Diffractive Optics to Semiconductor Laser Arrays
Authors: Leger J. R.
Published: February 2023

Optical interfacing to modern photonic devices presents several complex
design challenges. Semiconductor arrays, for example, require optics
that have high numerical apertures, low aberrations, and are
efficient.
Optical optimization of binary phase diffractive optical elements
Authors: Weible K.J. , Herzig H.P.
Published: February 2023

The application of simulated annealing to the optimization of phase diffractive optical elements has been investigated using large mainframe computers to perform the time consuming iterations.
Efficient, broad-band holographic axilens doublets for IR sources
Authors: Amitai Y. , Aharoni A. , Goodman J.W.
Published: February 2023

Recently, there has been rapid progress in developing semiconductor lasers as lowcost and compact monochromatic light sources for many applications.
Production of High Damage Threshold Diffractive Optics for Beam Smoothing
Authors: Lawson J. K. , Dixit S. N. , Morgan A. , Thomas I. M. , Woods B. W. , Powell H. T.
Published: February 2023

Diffractive optics based on binary phase patterns have proven valuable in homogenizing the focal plane intensity profiles of high energy laser systems used in Inertial Confinement Fusion (ICF).
Diffractive Optical Elements within a Matrix-Matrix Crossbar
Authors: Blair P. , Taghizadeh M.R. , Turunen J. , Robertson B.
Published: February 2023

The Optically Connected Parallel Machine (OCPM) is a matrix-matrix crossbar interconnect designed to provide high speed links between electronic processors.
Dynamic Study of Amorphous Tb-Fe Film for Magneto-Optic Memory Applications
Authors: Chen Tu , Treves David
Published: February 2023

Erasable optical storage techniques using thermo-magnetic writing and magneto-optic reading for high density digital recording have been a subject of recent interest. In this work, the magneto-optic (M-O) storage characteristics of the amorphous Tb-Fe thin films were investigated under dynamic conditions using a 76.2 mm diameter disk substrate and optical system.
Cover Sheets for Dust Protection
Authors: Marchant Alan B.
Published: February 2023

The problems of dust contamination of an initially clean optical disk can be alleviated by sealing the recording surface beneath a transparent protective layer. Overcoats, transparent substrates, and air-spaced cover sheets can be used to keep small particles out of the focal range of the objective lens and minimize their optical effects. The intrinsic optical properties required by such cover-sheet layers have been described.1 The purpose of this study is to determine the minimum layer thickness (or cover-sheet spacing) necessary to provide reliable optical isolation of dust on the surface of an optical disk.
Stability of 3M Draw Optical Recording Media
Authors: Chung C. H. , Alexander M. , Evanicky D. , Harrison C. W.
Published: February 2023

The 3M Optical Recording media consists of four essential layers. This quadri-layer structure is shown to be fundamentally stable in severe temperature and humidity environments. The impact of pregrooved plastic substrate materials on the stability of this structure is discussed.
Reversible Cycling Studies of Te-Alloy Films
Authors: Chen M. , Rubin K. , Marrello V. , Gerber U.G.
Published: February 2023

Tellurium-based alloys, which can undergo reversible amorphous-to-crystalline phase transitions, have been studied as potential reversible optical recording media candidates1. However, no Te-alloy has been reported to possess sufficient reversibility, data retention time, and adequate signal-to-noise ratio. Furthermore, the mechanisms responsible for reversibility failure are not understood or even identified.
Disk Drive Optical System Operation Under Environmental Stress
Authors: Deutschbein J. S. , Earman A. M.
Published: February 2023

A high-performance, field-ready Optical Disk System(1), currently under development at RCA, is designed to meet or exceed the performance capabilities currently required for most remote data collection applications. The system, contained in a single-console unit (Figure 1), includes all disk drive optics and mechanisms, data processing electronics(2), and on-board micro-controller unit. Data is transferred at 20 Mbps continuously or at 40 Mbps in bursts and the user data capacity is 5 x 1010 bits per disk side with no more than 1 in 108 bits in error. Data is recorded (in two parallel channels) using a dual-element CDH-LOC diode laser array. Two-channel operation affords closer track juxtapositioning than is possible with single element devices thus increasing data capacity by as much as fifty percent. A single HeNe laser beam is split into multiple beams by cascaded transmission phase gratings for dual-track readout and radial tracking control. The optical footprint at the recording plane is illustrated in Figure 2.
Reduction of Media Noise in Optical Disks
Authors: Nakajima M. , Hamada M. , Moribe M. , Hirano H. , Itoh K. , Ogawa S.
Published: February 2023

Improvement of carrier to noise ratio (C/N) is one of the most important problems of optical disk media.
Performance of an Erasable Organic Dye-Binder Optical Disk Medium
Authors: Gupta Mool C. , Strome Forrest
Published: February 2023

Write-once optical disks are emerging as an important medium for information storage. They provide high performance (in terms of carrier-to-noise ratio and bit error rates) and long life (~10 years). Extensive work has been published on write-once optical disk media based on organic dye-binder systems. Here we present some performance data for an erasable organic dye-binder optical disk medium.
A Compact Optical Head using Holographic Optical Element for CD Players
Authors: Kimura Y. , Sugama S. , Ono Y.
Published: February 2023

An optical head for optical disk system has three optical functions, in addition to light beam focusing on a disk. These are splitting the reflected beam from the optical axis, focusing error detection optics, and tracking error detection optics. Conventional optical heads have employed several bulky optical elements to realize these three optical functions, for example, a half mirror, a cylindrical lens and a spherical lens pair, and a grating, respectively. This complicated optics set up has prevented realizing a small size and light weight optical head.
Real Time Video Recording on Magneto-optic Disk
Authors: Nomura Tatsuo , Yokoyama Katsuya
Published: February 2023

In the past few years, with so much active work on magneto-optic memories, significant progress in both recording media and system performance has been made. In fact, magneto-optic memories are now at the practical stage for application to digital audio, and digital data file memories including still video file memories, where the recording bit rate is comparatively low.
Design of a Fiber Optic Read/Write Head for a Military Optical Disk System
Authors: Wilson Mark L. , Fritz Bernard S.
Published: February 2023

As the speed and capacity of advanced military computers increase, there is a growing need for fast high density memory systems. This report will detail work done at Sperry to develop a novel read/write head which will be used in a Write Once Read Many (WORM) optical disk memory system. The disk system will be used in a digital mapping unit for a tactical fighter aircraft which has extreme operating conditions.
Optical Data Storage with High Accessibility
Authors: Itao Kiyoshi , Yamada Ichiro
Published: February 2023

Because of the recent development of a rewritable magneto­optical disk, [1] optical disk memories are expected to be used as image database files and high-speed backup files for magnetic disk memories. However, currently, the accessibility of optical disks is still poor and needs urgent improvement.
Magneto-Optical Disk by Contact Printing Method
Authors: Inui Tetsuya , Hirokane Junji , Ohta Kenji , Yamaoka Hideyoshi , Ishikawa Toshio
Published: February 2023

A glass substrate has many advantages as an optical disk substrate. On a glass substrate, pits and grooves can be formed directly by a laser cutting machine and reactive etching.1) A highly reliable glass substrate can be obtained by this method, however, there is a problem of low productivity. It takes more than 30 minutes for patterning by laser cutting machine. This paper describes a contact printing method which can improve the productivity of conventional patterning, and discusses the signal performance of magneto-optical disks using a substrate prepared by the contact printing method.
Kerr rotation spectra for Fe/Cu, Fe/TiN, and Fe/Ag bilayer and multilayer media
Authors: Balasubramanian K. , Macleod H. A. , Marathay A. S.
Published: February 2023

Calculated Kerr rotation spectra for bilayer and multilayer media with Fe are presented. Kerr rotation enhancement, and the effect of the plasma reflection edge of adjacent metal reflector layers are studied.
Extremely Durable Cd-Rom With A Novel Structure
Authors: Yamaguchi H. , Tsukamoto Y. , Watanabe F. , Sato A. , Saito M. , Honda H. , Murahata M. , Yanagisawa M. , Tsuno T.
Published: February 2023

Commercially available read only optical disks, such as compact disks(CD) and CDROM, are susceptible to degrading corrosion of Al reflective films and their peeling-off from polycarbonate substrates1), and they lapse into a state of playback impossibility when the worst comes to the worst. Taking into consideration of the above serious problem, the authors succeeded in developing an extremely durable CDROM with a novel structure. This paper describes the structure and reliability on the extremely durable CDROM.
A Development of Non Compressed NTSC Digital Video Disk Recorder (2)
Authors: Katagiri T. , Nakamura K. , Itoi S. , Araki S.
Published: February 2023

Technologies for 32 minuetes digital recording of noncompressed video and 4 channel audio signals in a 300mm magneto-optical disk are reported.
Modeling and Design of Tracking Servo Signals for 2x and 4x Substrates
Authors: Arnett P. C.
Published: February 2023

With each new optical media product generation come rapid improvements in recording performance and density that require a reoptimization of disk parameters. One area of concern is optimization of the geometric design of tracking grooves and pre-formatted data on the disk substrate to support good seek performance in the drive. Guidance of design by scalar diffraction modeling supplemented with experimentally measured geometrical information has proven to be essential to the development of the highest quality optical disks.
Dual Focus Optical Head For 0.6mm and 1.2mm Disks
Authors: Komma Yoshiaki , Kasazumi Kenichi , Kanda Yoshihiro , Hayashi Hideki , Nishino Seiji , Mizuno Sadao
Published: February 2023

It is preferable to use thin (0.6mm) substrate to read a high density optical disk with a large numerical aperture (NA) lens1), because of allowance to disk tilt. Spherical aberration which is caused by disk thickness differences must be corrected to read conventional (1.2mm) disks. We propose a dual focus optical head with a holographic optical element (HOE) which corrects the aberration to read both 0.6mm and 1.2mm disks. It was confirmed that 0.6mm and 1.2mm disks can be read by the dual focus optical head.
Magnetic domain expansion readout of 0.16μm packed domains without crosstalk from adjacent track for a 0.60μm Tp L/G MAMMOS disk with RF readout field
Authors: Awano H. , Watanabe H. , Shirai H. , Shimazaki K. , Ohta N. , Yamaguchi A. , Takagi N. , Sumi S.
Published: February 2023

Magneto-Optical disk possesses very high advantage to record small domain compared to non magnetic optical disk, since MO recording is one kind of magnetic recording. Therefore, very small domain less than 0.1 μm on the MO disk can be recorded stable by using a laser pumped magnetic field modulation. However, the key issue is the readout because it is very small signal. In order to amplify the small signal, a small recorded domain is expanded by using readout magnetic field. This technique is called as Magnetic AMplifying MO System (MAMMOS) and reported that the readout signal of 0.08μm domain was 5 times larger than that of a conventional one, even if a conventional optical pick up of 680nm wavelength laser diode and numerical aperture of 0.55 was used. Thus, from previous papers, it is found that a bit density can be increased by MAMMOS. As a next step, a track density for MAMMOS readout field must be investigated. In this paper, magnetic domain expansion readout for L/G recording is reported by using a conventional optical pick up.
Artifacts Sources In Interferometry
Authors: Eastman D. R. , Martin C. A.
Published: February 2023

Spurious interference effects in interferograms are investigated. These artifacts are caused by ghost reflections, dirt, and diffraction effects. Diagnosis and cures are discussed.
A Simple Normal Incidence Micro-Reflectance Spectrophotometer
Authors: Kathuria Y.P.
Published: February 2023

With the growing interest in the investigation of the optical properties of semiconductors, thin- films and ionic crystals, it has become imperative to measure accurately the micro-reflectance of such miniature materials. Tubbs (1966), Esposito et al (1967), Collins (1966) and Peisner et al (1974) have reported different techniques for measuring the reflectance near normal incidence of very small areas of crystals. As in usual practise, the reflectivity of the micro-sample is determined irr comparison to the absolute reflectivity of the reference sample. Most of the authors have not met all of the following conditions required for precise measurement of absolute reflectivity.
Optical Testing Using Moire Deflectometry
Authors: Kafri O. , Livnat A.
Published: February 2023

We have recently suggested a method for measuring the deflection of rays of collimated light beams(1). The method is based on change in moire pattern due to ray deflection. It is diffraction-limited, so that, it obeys the uncertainty principle(2) expressed by :

Where Δy is the spatial resolution in the y direction and Δϕ is the minimun measurable deflection angle. Ray deflections can be obtained quantitatively and in a straight forward fashion from the distorted fringes of the moire pattern. For example, with λ= 0.6μm and spatial resolution of 1mm one can measure Δϕ = 6.10-5 rad.
High Speed Polishing of Glass Lenses
Authors: Hed P. Paul
Published: February 2023

High speed polishing is a polishing process which, unlike conventional polishing, requires neither tool adjustment during the polishing cycle nor frequent tool and machine-stroke corrections. Such a process should be very consistent. In order to achieve this consistency several conditions should be met: the lens blocker must run true, the curvature ground on the lens must be correct, the spindle speed, arm stroke, lap load and lap aperture must be maintained constant and tuned to each other and to the ground curve; the polishing slurry density, pH value and temperature must be controlled, etc. Now, no one should expect to receive an absolute recipe on how to do all these things, considering the fact that there are so many variants, such as blocker size, lens size, lens radius, material and tolerances, etc., etc. There are many years of investigations ahead of us. In the meantime, it is mandatory to run a pilot run for each job, in order to establish all the parameters before giving the production tools to the operator.
Using Calculators and Computers in the Shop
Authors: Brown Norman J.
Published: February 2023

About five years ago I began working on wear programs for use with calculators sufficiently inexpensive that they could be accounted as tooling and set up for small shop use. As recently as the 1980 OSA Spring Conference I was publishing techniques for programmable hand calculators as most suitable under these restrictions. In the short interval since, the small personal computer has come of age and become big business. Today there are small units at least a thousand times faster than the hand calculator and usually with at least CRT graphics capability sufficiently inexpensive for this application. They are interactive and have sufficient memory and flexibility to give almost immediately answers that were previously unasked because of the time involved. These new machines have obvious uses in the managerial area where computers have been used for some time in larger companies. An example of this is the statistical quality assurance program discussed at this meeting. However, their low cost and flexibility now brings them to a new group of users, the opticians themselves, giving them tools that were once only in the province of engineers. Another paper at this meeting brings this point home with a listing of a broad variety of problems, most of them simple, but of daily concern in the shop. These could all be stored on a single tape to be called up as needed. This paper will exemplify a more complex problem, but one as simply handled, the planning of an aspheric figuring process. Since the calculations are treated .in the literature, it will concentrate on the flow logic, a simplified block diagram necessary to make these practically available on a routine basis to an optician on the shop floor. Since these people are seldom trained in computer usage, the interactive sequence must be simple. It is reduced to the following. At each decision point, the computer asks a simple question so phrased that it may be answered by a simple yes or no, by typing Y or N on the teletype. Once this decision has been made, the computer can request the data necessary in a rather specific form such as "type in the clear aperture in millimeters." Where the question needs further explanation, this can be provided by graphics. For example, as the optician specifies zones to be worked, pad sizes etc., each can be plotted on a CRT screen with the next range of options superimposed so that he can see what he must next choose.
Optical Coatings From the Users' Point of View
Authors: Mott Leonard , Baumeister Philip
Published: February 2023

A common assumption in the design of optical systems is that coatings do not influence certain optical characteristics, such as image quality. Is it not true that, in most cases, the functional performance and quality of an optical component are measured before coatings are applied? The tacit assumption is that after application of the coating, the optical and mechanical properties are unaltered. Such assumptions are often unwarranted.
Columnar and Nodular Growth of Thin Films
Authors: Guenther Karl H.
Published: February 2023

It is meanwhile common knowledge that most PVD thin films usually reveal a columnar microstructure, with a few exceptions only. The microstructure depends on the deposition method, the substrate temperature and film thickness, to name only a few out of various determining parameters.
Plotting Errors Measurement in CGH Using an Improved Interferometric Method
Authors: Ono Akira , Wyant James C.
Published: February 2023

Computer generated holograms1 (CGH) are very useful to test aspherical lenses or mirrors. Accurately drawn CGH's are required to test precisely. J.C. Wyant et al presented an interferometric method2 that can measure plotting errors of equispace straight lines or dots in CGH's. In the interferometric method, an original pattern drawn by the plotter has to be reduced to a small photo-film. The measured plotting error must then include an error caused by a photo lens aberration.
Visible Light Diffraction Image Evaluation of Grazing Incidence Optical Systems
Authors: Takacs P. Z. , Colbert J.
Published: February 2023

Optical systems designed to utilize extreme ultraviolet (EUV) and x-ray photons from synchrotron radiation (SR) light sources with grazing incidence optics generally have entrance apertures that are long in the horizontal plane and narrow in the vertical plane. Apertures that are 1 mrad high by several milliradians wide at a distance of 10 meters from the source are typical. A point source illuminated by a red He-Ne laser beam imaged through a system with this aperture and focal length results in a 1.2 mm high image that is severely broadened by diffraction. Component alignment with visible light is difficult when the diffraction limit is so severe. The use of visible light for system alignment is, however, a necessity, because alignment under actual operating conditions and at operating wavelengths in ultra high vacuum chambers is totally impractical. Except for rare instances, components are not accessible for alignment adjustments. How, then, can we make use of the information available in the severely diffraction-limited visible image to assess the performance of our system at x-ray wavelengths?
Micro-Optical Components for Fiber Optic Connectors
Authors: Bowen Terry , Garner Mike
Published: February 2023

Micro-Optical components play an important role in many fiber optics systems. Design considerations, design options, and applications in a variety of specialized system components are reviewed.
From angstroms to microns: Extending the measurement range of optical profilers
Authors: Creath Katherine , Wyant James C.
Published: February 2023

Optical profilers are very good for looking at the microstructure of a surface; however, they do not provide a very large dynamic range. They are limited to slopes which don't change the optical path difference between adjacent pixels by more than a half of the measurement wavelength (this corresponds to height changes of one-quarter wave). Many possible applications of optical profilers call for measuring the height of a step which is greater than a quarter of a wavelength, or for looking at structures of rough surfaces. Using the techniques of two-wavelength phase-shifting interferometry,1-4 the dynamic range of an optical profiler can be extended without sacrificing its high measurement precision.
Extending the Measurement Limits of an Optical Surface Profiler: Combining Subaperture and Two-Wavelength Techniques
Authors: Cochran Eugene R. , Creath Katherine
Published: February 2023

One of the more favorable candidates for determining the microtopography of optical surfaces is the interference microscope. This instrument combines the basic functions of a microscope with those of an interferometer. The microscope, which provides a high numerical aperture and thus excellent resolving power, is modified to operate as an interferometer enabling the acquisition of phase information about the surface under examination. This phase information can easily be translated into surface height information. Using phase-modulated interferometric techniques, it becomes possible to obtain very good vertical height resolution along with an excellent lateral resolution, which is provided by the microscope objective. Interference microscopes provide a quick, non-contact, and very repeatable way of measuring optical surface profiles.
Mechanical Fatigue of Silica Glass
Authors: Tomozawa Minoru
Published: February 2023

Mechanical strength of glass decreases with time when stressed in an atmosphere containing water. Also, the greater the tensile stress on the glass, the shorter the time to failure if the stress is held constant. This can limit the service life of various glass products such as optical wave guides made of silica glass fibers. Often this mechanical fatigue is explained by slow crack growth [1]. Namely, it is postulated that a small crack exists on the glass surface and that this crack propagates slowly under an applied stress leading eventually to a failure. The failure time, then, is the time required for a crack to grow to a critical length. The role of the water in the environment is believed to be the acceleration of the crack growth rate. According to this explanation, one can estimate the service life-time of a glass under stress using data on slow crack growth rate. Thus there have been numerous measurements of the crack growth rate of glass under varied stress and environment. In this explanation of mechanical fatigue based upon slow crack growth, it is tacitly assumed that the crack tip geometry of the specimen which shows mechanical fatigue is the same as that of the propagating crack observed in the crack growth measurement. If this assumption is not valid and the crack tip geometry of the sample is different from that of the propagating crack, then the explanation of the mechanical fatigue based upon the slow crack growth would not be valid. In this paper, therefore, first, the crack tip geometry of silica glass (and high silica glass) after various thermal and chemical treatment will be discussed. Subsequently, the fatigue characteristics of these treated glass will be described and will be related to the crack tip geometry.
Inorganic-Organic Polymers as Materials for Optical Applications
Authors: Schmidt H.
Published: February 2023

The use of organic polymers for optical purposes requires special properties: The refractive index should be high or able to be adapted, light scattering should be extremely low, low thermal expansion and high surface hardness are advantageous. Temperature stability should be as high as 100 to 120 °C. Only a few organic polymeric materials have been used for optical purposes in the past e.g. PMMA, polycarbonate, polystyrene and CR 39 for eye glass lenses. Materials for contact lenses are a speciality, since additional requirements such as non-toxicity, oxygen permeability or surface hydrophilicity exist.
Inspection of Large Area and Large Volume Optics by Raster Scanning
Authors: Stover John C. , McGary Douglas E. , Rifkin Jeff
Published: February 2023

Scattered light is a problem in many optical systems. Increasingly, scatter is becoming recognized as the real issue with component specifications written in terms of the BSDF (bidirectional scatter distribution function) instead of the often less appropriate surface finish parameters (rms roughness, etc)[1,2]. Additionally, the presence of light scatter from a local area, on an otherwise uniform optic, indicates the presence of a defect or a contamination site. Unfortunately, complete sample coverage by full angle BSDF inspection is often impractical due to time and cost limitations imposed by sample size and/or sample numbers. For these situations a raster scanning technique which rapidly covers the required area may be the best solution. Raster data provides valuable insights into sample non-uniformity caused by production processes and contamination.
Polarization Filtering in Real-Time Speckle Metrology
Authors: Collicott Steven H. , Hesselink Lambertus
Published: February 2023

The polarization properties of multiple exposure speckle patterns recorded in a photorefractive crystal (Bi12SiO20) are exploited to improve the signal-to-noise ratio in real-time speckle metrology and velocimetry. Previous work1 demonstrates the feasibility of real-time photorefractive recording and optical processing of multiple-exposure speckle patterns for metrology and velocimetry applications. The speckle patterns are produced by a coherent imaging system, a scattering object, and a Q-switched Nd:YAG laser. The multiple-exposure is immediately interrogated with a CW laser and processed optically. The resulting fringe pattern contains two-dimensional displacement or velocity information in real-time. The effects of speckle recording on the polarization properties of the photorefractive crystal shows that polarization filtering separates a portion of the signal from the background noise in the optical processor. This produces an increase in the contrast of the fringe pattern in the output plane of the optical processor. Polarization filtering may also reduce the energy density incident on the crystal necessary to produce a signal of given strength. Experimental results demonstrating the improved signal in real-time speckle velocimetry are shown.
Spherical Grinding Wheel Use and Fabrication
Authors: Ketelsen Dean , Parks Robert E.
Published: February 2023

Contour grinding of fast aspheric surfaces is a method of achieving the final polished surface more rapidly than trying to polish in the asphere from a sphere. The most efficient method is to do a good enough job with the contour grinding that it is possible to go directly to polishing. This requires that the surface be accurately ground, that it be largely free of ripple due to the tool feed marks and that the subsurface damage be small enough that it will polish out rapidly. The first requirement depends on the N/C contour grinding machine but the other two requirements are a function of the grinding wheel.
Mechanics of Material Removal in Single-Point Diamond Turning of Brittle and Amorphous Optical Materials
Authors: Scattergood Ronald O.
Published: February 2023

Optical materials such as ceramics and glass are not usually amenable to machining operations because of their poor fracture toughness and attendant brittleness. However, production of optical surfaces using machine tools has the advantage that a complex form can be deterministically generated, for example, an aspherical surface. Consequently, considerable interest exists in developing single-point diamond turning and diamond grinding technologies for brittle materials. Very high stiffness, precision machine tools must be used to control the process and, in particular, avoid surface fracture damage. Under appropriate conditions, "ductile-regime" machining conditions can be achieved wherein the material removal appears to take place by ductile shear rather than brittle fracture. However, material removal mechanisms underlying ductile-regime machining processes are not well understood. The work reported here is aimed at gaining a better understanding of the mechanisms that underlie these processes. The development and verification of models for single-point diamond turning will be addressed.
High accuracy interferometric radius of curvature measurement
Authors: Selberg Lars A. , Hunter George C.
Published: February 2023

The primary sources of error for interferometric radius measurement (Fizeau and distance measuring interferometers) are tooling stability and air turbulence. Secondary error sources are also discussed.
The Ross null test for conic mirrors.
Authors: Stoltzmann David E. , Ceravolo Peter
Published: February 2023

Various null-testing arrangements have been used over the years, for testing concave non-spherical mirrors. We have researched a method for null testing which uses a single plano-convex lens to compensate for the spherical aberration of a concave mirror, when tested at its center of curvature. This testing method, called the Ross test, requires a high-quality null lens and a standard Foucault tester. In this article, we present graphical and numerical data which provides the necessary parameters for implementing the Ross null test, for mirrors having focal ratios ranging from f/3.5 to f/10.0, and for conic deformations ranging from eccentricities of 0.70 to 1.50.