Ronald Martin Horn

General Electric Hitachi · Primary Author

Powder bed fusion Direct Metal Laser Melting (DMLM) is an evolving additive manufacturing (AM) fabrication technology that is providing high performance parts to many industries. This technology has significant promise for use in building components for nuclear power plants. Implementation of materials produced using this and similar processes offe...

Powder bed fusion Direct Metal Laser Melting (DMLM) is an evolving additive manufacturing (AM) fabrication technology that is providing high performance parts to many industries. This technology has significant promise for use in building components for nuclear power plants. Implementation of materials produced using this and similar processes offe...

Introduction Previous laboratory studies using stabilized stainless steels Experimental results Discussion of results Conclusions Acknowledgements

Introduction SCC Analysis Data At Constant Load – Disposition Relationship for Low Alloy Steels in BWR Water Conclusions

Introduction Experimental Procedure Results Discussion

The ageing testis is associated with germ loss in the seminiferous epithelium and a decrease in spermatogonia proliferation. In this work, we study whether the stages of the seminiferous epithelium cycle and/or the degree of histological tubular degeneration resulting from ageing is related with this decrease in spermatogonia proliferation. Eleven...

This section is directed at reviewing the control rod structural designs and materials used in light water reactors (LWRs). This chapter provides the background on the design and approaches used in both the boiling water reactors (BWRs) and pressurized water reactors (PWRs). However, given the differences in operation between the reactor designs, t...

This chapter focuses on the environmentally assisted cracking (EAC) and, more specifically, the intergranular stress corrosion cracking (IGSCC) of austenitic stainless steels and nickel base alloys exposed to the recirculating boiling water reactor (BWR) environment. The fundamental factors for IGSCC of BWR piping materials, a discussion of life pr...

NUREG-1801, Rev. 1, Section XI.M.13, states that an ASME Code Section XI VT-3 examination is required to be performed of reactor internal components. In addition, the NUREG report specifies that for the license renewal period, these inspections shall be augmented by an aging management program to assess the synergistic effects of thermal aging and...

The growth kinetics of stress corrosion cracks at the dissimilar weld interface between A533B low alloy steel and alloy 182 cladding under BWR conditions were investigated. The main objective of this study is to determine potential threshold conditions required for a crack initiated in alloy 182 to propagate into the A533B. Tests were conducted usi...

The susceptibility of Light Water Reactor (LWR) components to stress corrosion cracking (SCC) continues to be governed by the operating environment as well as the microstructure of the structural materials used for key components. In operating boiling water reactors (BWRs), significant efforts have been undertaken to proactively address SCC through...

In this study, we examined the age-related changes on morphometric parameters and ultrastructure of seminiferous tubules, and on the expression of extracellular matrix proteins in lamina propria of Syrian hamsters. A significant decrease in the percentage of normal tubules and an increase in the percentage of hypospermatogenic and arrested maturati...

The cellular mechanisms implicated in the atrophy of seminiferous epithelium in ageing are currently under debate, although recent reports suggest that apoptosis may be the primary mechanism implicated in aged germ cell loss. Other investigators have suggested that changes in spermatogonial proliferation are also involved. In the present work, the...

In the hamster, male reproductive quiescence is accomplished via testicular atrophy and the germinal epithelium is regressed to spermatogonia and spermatocytes after 8-14 weeks of short photoperiods. However, the cellular mechanisms involved in this process have not been elucidated. As it is suggested that the regulation of seasonal testicular acti...

The reactor pressure vessel (RPV) to shroud support weld (termed as H9 weld) of a Boiling Water Reactor-2 (BWR-2) was examined during a refueling outage. The ultrasonic (UT) examination was performed from the upper conical support plate surface for all accessible areas of the H9 weld. A fracture mechanics evaluation was conducted to justify continu...

The diagnostic potential of technetium-99m hexamethylpropylene amine oxime (HMPAO) following systemic administration of the cerebral vasodilator acetazolamide (acetazolamide test) was evaluated by regional cerebral blood flow (rCBF) single-photon emission tomography (SPET) in patients with Alzheimer's disease (AD) or vascular dementia (VD). An init...

Zusammenfassung: Zur leichteren Anwendbarkeit des in der Demenzforschung mehrfach und in verschiedener Weise benutzten Uhrzeichen-Tests im Rahmen psychodiagnostischer Verfahren sollten Merkmale gefunden werden, die eine diagnostische Differenzierung zwischen «Alzheimer-Patienten», «Depressiven» und «Gesunden» erlauben. Insgesamt 205 Patienten einer...

The diagnostic potential of 99mTc-HMPAO following systemic administration of the cerebral vasodilator acetazolamide (acetazolamide test) was evaluated using regional-cerebral-blood-flow (rCBF) SPECT in patients with Alzheimer's disease (AD) or with vascular-type of dementia (VD). An initial, high-resolution SPELT study was performed with 99mTc-HMPA...

The Auditory Verbal Learning Test (AVLT) is widely used in scientific research as well as in clinical practice. But there exists little research on the structure of the AVLT. We investigated the structure of a German version of the AVLT and VLMT, in 232 patients of a psychiatric clinic and in 872 patients of an epileptologic clinic. First we stated...

In clinical practice, Alzheimer's disease (AD), multi-infarct Dementia (MID) and depression are often difficult to differentiate and may coexist. This study reports the findings of CT and MRI focused on hippocampal atrophy (HA). Quantitative volumetric MRI measurements of the hippocampus showed a reduced volume in AD patients compared to normal con...

The histological and morphometric features of the aged golden hamster testis were examined and compared with those of adult animals. Three age groups (6, 12 and 18 months) were studied by light microscopy, and testosterone levels were determined. The observations showed a progressive involution of the seminiferous tubules, beginning to be perceptib...

Das gesunde Erwachsenen-EEG ist durch eine topische Differenzierung der corticalen Aktivität gekennzeichet. So wurden faktoren- und cluster-analytisch 3–4 voneinander abgrenzbare Hirnregionen beschrieben: anterior, central und posterior [4] bzw. frontopolar, fronto-zentral, temporal und parieto-okzipital [3]. Psychiatrische Erkrankungen lassen sich...

The glycoconjugates of hamster epididymis were investigated with conventional and lectin histochemistry. A zone of the caput epididymis, with particular histochemical characteristics, has been differentiated. beta-Elimination in combination with lectins was used to establish the presence and distribution of N- and O-linked glycoconjugates. The epit...

The morphology of the spermatozoa in the cauda epididymidis of 6- and 24-month-old (adult and aged) hamster was studied by electron microscopy. Lesions found in the spermatozoa included alterations in the acrosomal matrix and nuclear membranes, abnormal or absent mitochondria, alterations in the axonemes, dense fibres and microtubules, and bent fla...

Zusammenfassung Fünfzehn Patienten mit der DSM-III-R Diagnose einer Panikstorung mit oder ohne Agoraphobie und fünfzehn ihnen nach gleichem Alter und Geschlecht zugeordnete Patienten mit einer chronischen primären Insomnie wurden im Schlaflabor in 3 aufeinanderfolgenden Nächten untersucht. Als Maβ für Angst und Depressivität wurden die Hamilton-Ska...

Description Compiles information from the world's leading experts on how best to meet the needs of designers, consumers and marketers of materials data. 18 comprehensive, peer-reviewed papers from an international body of materials data professionals are divided into the following key areas: Concurrent Engineering, Organization and Process of Mater...

The respiratory submucosal glands are a major source of secretions in the airway. Human submucosal laryngeal glands have been scarcely studied, with no works existing about their ultrastructure and histochemistry. Samples of epiglottis, ventricle, false vocal folds and true vocal folds were fixed in 10% buffered formalin for histochemical study wit...

The development of low cost material processes is essential to the achievement of economical liquid rocket propulsion systems in the next century. This paper will present the results of the evaluation of some promising material processes including powder metallurgy, vacuum plasma spray, metal spray forming, and bulge forming. The physical and mecha...

The aim of the present study was to see whether HMPAO-SPECT may contribute to the differentiation between dementia of the Alzheimer type (DAT) and major depression (MD). The results in 77 patients with memory impairment were evaluated. 48 patients suffered from DAT and 29 from MD. Initially, the defects in SPECT imaging were attributed to a cerebra...

The study herewith represents the conception of the Bonn "anxiety"-ambulance, which was established in the University of Bonn, Department of Psychiatry, in January 1991. Besides we report our experiences from the first four months after opening of our ambulance and present first results.

The differentiation between the Alzheimer and multi-infarct types of dementia may still be equivocal considering clinical criteria, neuropsychological tests, and imaging techniques. Cerebral microangiopathic alterations underlying multi-infarct dementia should allow the characterization of dementia subgroups. Patients with a diagnosis of multi-infa...

In der Differentialdiagnose dementieller Prozesse werden CCT und MRT Untersuchungen in erster Linie zum Ausschluß behandelbarer Ursachen wie z.B. eines Hydrozephalus, subduraler Hämatome und Tumore eingesetzt.

Die differentialdiagnostische Abgrenzung der Demenz von der depressiven Pseudodemenz zählt zu den schwierigsten Aufgaben des in der Gerontopsychiatrie tätigen Klinikers. Seit Kraepelin ist bekannt, daß die Depression die kognitiven Funktionen beeinträchtigen kann. 1952 führte Madden den Begriff der „Pseudodemenz“ein, um damit reversible kognitive S...

Im Rahmen unserer seit einem Jahr bestehenden „Gedächtnissprechstunde“wurde eine psychologische Testbatterie bei 20 Patienten mit der Diagnose „Alzheimer- Erkrankung“(AD) nach den Kriterien des DSM-III-R sowie 13 Patienten mit Multi- infarktdemenz oder anderen zerebrovaskulären Erkrankungen (MID) durchgeführt (Tabelle 1).

Die Demenz vom Alzheimer Typ (DAT) ist durch klinische wie auch bestimmte morphologische, neurophysiologische und neuropsychologische Veränderungen gekennzeichnet. Insbesondere die P300- und Reaktionszeitbefunde sprechen dafür, daß die Qualität und Geschwindigkeit der zentralnervösen Informationsverarbeitung bei dieser Erkrankung reduziert ist (Pol...

Bei Patienten mit einer Demenz vom Alzheimer Typ werden typische EEG Befunde beschrieben [1], die sich unter der Gabe von Nootropika verändern können [2, 5]. Andererseits sind EEG Veränderungen unter der Gabe von cholinergen Substanzen [6] und auch unter anticholinergen Substanzen wie Scopolamin gleichzeitig mit Veränderungen der kognitiven Leistun...

Bisher stand keine Methode zur Verfügung, um ohne großen Aufwand und Belastung für den Patienten Aussagen über die hämodynamischen Veränderungen während und direkt nach einem durch EKT ausgelösten Krampfanfall zu machen. Es konnte gezeigt werden, daß der cerebrale Metabolismus und cerebrale Blutfluß (CBF) während eines generalisierten Anfalls deutl...

Als am häufigsten zu beobachtende EEG-Veränderung im Rahmen einer Elektrokrampftherapie (EKT) beschreibt Weiner [1] eine diffuse Zunahme langsamer Aktivität, die sich im Laufe der EKT allmählich entwickelt und sich in den meisten Fällen bald nach deren Beendigung wieder zurückbildet. Dabei lassen sich im wesentlichen zwei Muster der Verlangsamung b...

Da die klinische Differentialdiagnose dementieller Prozesse speziell in den Frühstadien der Erkrankung schwierig ist, suchen wir nach zusätzlichen Hinweisen aufgrund anderer Untersuchungsverfahren. Aus neuropathologischen Untersuchungen ist bekannt, daß sich die pathologischen Veränderungen beim M. Alzheimer (AD) auf den Hippocampus, hauptsächlich...

Zusammenfassung Ziel der vorliegenden Untersuchung war es, zu prüfen, ob die HMPAO-SPECT zur Differenzierung zwischen der Demenz vom Alzheimer-Typ (DAT) und der Major Depression (MD) beitragen kann. Es wurden ECT-Befunde von 77 Patienten mit Gedächtnisstörungen beurteilt, davon hatten 48 eine DAT und 29 eine MD. Zunächst wurden die Defekte in der S...

Gegenüber Basalwertuntersuchungen versprechen pharmakologische oder physiologische Stimulationsmethoden, wie z. B. der therapeutische Schlafentzug, einen besseren Einblick in die Pathophysiologie depressiver Patienten zu geben. Durch den therapeutischen Schlafentzug (SE) kann bei einem Großteil depressiver Patienten ein rasch einsetzender, jedoch t...

The measurement of regional cerebral blood flow (rCBF) by the mTc-hexamethyl-propylenamineoxime single photon emission computer tomography (HM-PAO-SPECT) and 133Xe inhalation methods is usually described as facilitating the clinical diagnosis of Alzheimer’s disease, which is difficult to diagnose with certainty. In particular, substantial rCBF abno...

After supratentorial infarction crossed cerebellar diaschisis has been described. This report concerns the rare phenomenon of crossed cerebral diaschisis in cerebellar infarction. Relative distribution of cerebral and cerebellar blood flow was measured using three-dimensional, qualitative single-photon-emission-computed-tomography (SPECT) with a ro...

This paper presents the results of a research program conducted to evaluate the behavior of stress corrosion cracks in sensitized austenitic piping exposed to high temperature, high purity oxygenated water. The program was directed toward the development of a predictive method which included a design margin assessment and an evaluation of crack gro...

This report presents the results of a research program conducted to evaluate the behavior of hypothetical stress corrosion cracks in large diameter austenitic piping. The program included major tasks, a design margin assessment, an evaluation of crack growth and crack arrest, and development of a predictive model. As part of the margin assessment,...

This report presents the results of a research program conducted to evaluate the behavior of hypothetical stress corrosion cracks in large diameter austenitic piping. The program included major tasks, a design margin assessment, an evaluation of crack growth and crack arrest, and development of a predictive model. As part of the margin assessment,...

We have studied the effect of N-bromoacetamide (NBA) on the behavior of single sodium channel currents in excised patches of rat myotube membrane at 10 degree C. Inward sodium currents were activated by voltage steps from holding potentials of about -100 mV to test potentials of -40 mV. The cytoplasmic-face solution was isotonic CsF. Application of...

Voltage-dependent Na conductance of rat myotubes was studied by patch recordings of single-channels. The patches were excised from the cell with the patch electrode, and the cytoplasmic surface was bathed in either CsF or tetramethylammonium (TMA)-F. Inward currents were examined from -20 to -50 mV. In this range Cs and TMA both appeared to be near...

Most, if not all, types of voltage-gated channels inactivate. Channels that have been driven open by a depolarization will enter a non-conducting, inactivated state if the depolarization is maintained long enough. This inactivated state is different from the resting closed state because inactivated channels cannot be forced open by depolarization....

The currents through single acetylcholine-activated channels were measured on membrane fragments that had been torn from rat muscle myotubes with patch pipettes. The membrane fragments were sealed into the pipette by using the "gigohm-seal" technique of Neher, which also permitted voltage clamp of the membrane via the patch electrode. Membrane patc...

Investigations of austenite decomposition have been undertaken in (1) Fe-0.5Mn-1V-0.2C and (2) Fe-0.5Mn-3Ni-1V-0.2C alloys. Isothermal transformation characteristics were determined using dilatometric and thermo-electric potential techniques. Also, micro-structural features were observed using optical and transmission electron microscopy for treatm...

An investigation was carried out to study the microstructure and mechanical properties of isothermally transformed AISI E 52100 steel. Heal treatments consisting of single and two cycle austenitization followed by isothermal holding resulted in duplex structures of martensite and bainite. In addition, high temperature austenitization led to large a...

The National Energy Plan calls for a doubling of the use of coal in the next decade. Toward the end of the coming decade, it is anticipated that a new large scale technology will be developed that will convert much of this coal into oil and gas. A key component of the new technology is the thick wall pressure vessel used for the gasification of the...

An investigation into the mechanisms of tempered martensite embrittlement (TME), also know as “500°F” or “350°C” or one-step temper embrittlement, has been made in commercial, ultra-high strength 4340 and Si-modified 4340 (300-M) alloy steels, with particular focus given to the role of interlath films of retained austenite. Studies were performed o...

A study has been made of the influence of austenitizing temperature on the ambient temperature toughness of commercial AISI 4340 ultrahigh strength steel in the as-quenched (untempered) and quenched and tempered at 200°C conditions. As suggested in previous work, a systematic trend ofincreasing plane strain fracture toughness(K) Ic anddecreasing Ch...

The relationships between microstructure and fatigue crack propagation behavior were studied in a 5Mo-0.3C steel. Microstructural differences were achieved by varying the tempering treatment. The amounts, distribution, and types of carbides present were influenced by the tempering temperature. Optical metallography and transmission electron microsc...

A summary is presented of progress during the first year of a program to modify current ferrous alloys and develop new low-alloy steels that can be field-fabricated into large-diameter, thick-walled pressure vessels for commercial coal gasifiers. Determination of design criteria for the pressure vessel steels, incorporating information gained throu...

The strength of stainless steel weldments in nuclear piping systems is typically chosen larger than that of the base piping material to address welding uncertainties. Associated with this higher strength one often finds a degradation in fracture toughness and reduced ability to support load in the presence of a weldment crack. In this research, typ...