bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Combustion Gas Turbine - Historical Development and Present Day Applications to Natural Gas Pipelines
Authors: Park Tracy S. 
Published: May 2009

Introduction
The gas turbine has attained commercial significance as a competitive prime mover only in recent years. Few other mechanisms have had as much time and effort devoted to their development, and with such limited success prior to the present combustion type. Apparently misled by its simplicity, countless inventors have experienced repeated failures in their attempt to achieve a successful machine. It is logical to inquire why a practical design was not evolved during these hundreds of years of experimentation. The plaything of Hero, Newton, comic strip artists, dreamers, jet propulsion enthusiasts, and many sane, capable engineers, has only recently reached its present stage of development. Only a handful of industrial gas turbines are now in service, and the principles of operation are not widely known
The successful development of the gas turbine is closely associated with the utilization of elevated temperatures and a highly efficient air compressor. Most of the progress realized is therefore directly attributable to efforts of metallurgists and aerodynamicists. The main difficulty has been in building a turbine that can develop more power than is consumed by its own air compressors. The superior materials available today permit operation at elevated temperatures, and progress in fluid research has resulted in a highly efficient axial flow compressor. The inherent simplicity of the gas turbine, and its independence of water facilities and complex auxiliaries, ideally adapts it for certain classes of service. Examples are rail locomotives, electric power generators, gas compressor units, and marine applications.

Historical Outline
Current publicity appears to have created the impression among the general public that the gas turbine is an invention of recent origin. To dispel an erroneous conception, it is worthwhile to delve into the general background of this prime mover and observe the antiquity associated with the art.
Strength Of Oil Well Cements And Additives Under High Temperature Well Conditions
Authors: Saunders Calvin D. , Walker Wayne A. 
Published: May 2009

Abstract
Recent tests have shown that the strengths of cement will decrease with increase in temperature and age above a critical temperature. The critical temperature appeared to be approximately 220 degrees to 240 degrees F.
This paper presents results of tests which were designed to determine, if possible, the cause and means for overcoming this strength loss. Various types of cements and additives were evaluated in this investigation. These data are the results of tests made to date in this investigation.
No definite conclusions are drawn at this time, but it appears that by the proper selection of additives for cement, strength loss with age at high temperatures can be either eliminated or considerably lessened.

Introduction
The strength of oil well cement is usually considered to increase with increasing temperature under the normal conditions prevailing in an oil well. Only recently the fact that the strength of the cement decreases rapidly with high temperature and age was brought to the attention of the industry. The data presented in a paper, prepared by the API Mid-Continent District Study Committee on Cementing Practices and Testing of Oil Well Cements, given at the 1954 Spring Meeting of the Mid-Continent District showed that all types of Portland and oil well cements tested had much less strength when cured at 320degrees F than when cured at 200 degrees F. Also this paper contained data showing some cements had a retrogression of strength with time as the cement was cured at 320 degrees F, with some cements losing more than 50 per cent of their one-day strength after 14 days. This paper offered no explanation as to what remedies might be taken to alleviate or eliminate this strength retrogression.
An Analysis of the Linear Displacement of Oil by Gas-Driven Solvent
Authors: Johnson Edward F. , Welge Henry J. 
Published: May 2009

Abstract
A method of calculation is presented for predicting the performance of a solvent extraction process. The process proposed involves the displacement of oil by a liquid solvent which is moved through the reservoir by a driving gas. The gas evaporates solvent at the point of first contact, and condenses the solvent vapor farther downstream. This condensation swells the oil and decreases its viscosity, thus making displacement of the oil easier. It has been predicted theoretically that 100 per cent recovery of oil is possible.
A formula is derived which permits calculation of the minimum solvent requirement to secure complete oil recovery. Also derived are formulas for calculating the average residual oil saturation left when less solvent is used, and the flowing gas-liquid ratios emerging from the porous body. Appropriate material balance equations are presented to provide a check on the correctness of the derivations and the precision of the calculations. The solution of a typical gas-driven solvent problem requires a few hours' time on a medium-speed computing machine.
Curves are given in the paper which illustrate the results obtained in the calculations. The theoretical results compare very favorably with experimental studies made on long cores. For a given quantity of injected solvent and a given throughput of gas in pore volumes, the displacement of oil is not very sensitive either to the pressure level employed, or to the type of sandstone.

Introduction
The recovery of oil by solvent extraction is currently receiving much attention. Part of this interest is no doubt due to the fact that oil recoveries up to 100 per cent may be obtainable in the contacted or swept portions of the reservoir.
The Riemann zeta-function and moment conjectures from Random Matrix Theory
Authors: Steuding Jörn 
Published: May 2009

Abstract
On the basis of the Random Matrix Theory-model several interesting conjectures for the Riemann zeta-function were made during the recent past, in particular, asymptotic formulae for the 2kth continuous and discrete moments of the zeta-function on the critical line, $$
\frac{1}
{T}\int\limits_0^T {|\zeta (\tfrac{1}
{2} + it)|^{2k} dt} and \frac{1}
{{N(T)}}\sum\limits_{0 < \gamma \leqslant {\rm T}} {|\zeta (\tfrac{1}
{2} + i(\gamma + \tfrac{\alpha }
{L}))|^{2k} }
$$, by Conrey, Keating et al. and Hughes, respectively. These conjectures are known to be true only for a few values of k and, even under assumption of the Riemann hypothesis, estimates of the expected order of magnitude are only proved for a limited range of k. We put the discrete moment for k = 1, 2 in relation with the corresponding continuous moment for the derivative of Hardy’s Z-function. This leads to upper bounds for the discrete moments which are off the predicted order by a factor of log T.
Chosen Problems of Road Accidents Analyses in Poland
Authors: Kisilowski Jerzy , Zalewski Jarosław 
Published: May 2009

Chosen Problems of Road Accidents Analyses in Poland
This article offers classification of car collisions from the point of view of the most frequent accidents and crash tests. The most important problems are the consequences of incomplete control of a car. The article focuses on the safety of road traffic in Poland and presents an attempt to analyze the causes of most frequent collisions and their consequences. It gives statistical data and attempts to analyze the level of road traffic safety. Some important indicators are shown here to compare the situation in France and Poland, which enabled verification of some opinions about road traffic safety in Poland.
Preventive Maintenance with Imperfect Repairs of a System with Redundant Objects
Authors: Okulewicz Józef , Salamonowicz Tadeusz 
Published: May 2009

Preventive Maintenance with Imperfect Repairs of a System with Redundant ObjectsAn object ability to realise tasks may be restored by repairing only failed components. This is called imperfect repair, as the object is not as good as new after such a repair. Preventive replacement is an example of imperfect repair as well. The advantage of such maintenance is that it enables controlling a reliability level of a system. Sets of objects' components that should be replaced are derived on a basis of statistical diagnosing with use of data about components failures. The acceptable level of a failure risk while executing transportation tasks has been taken as a criterion of choosing elements to be replaced. An algorithm of selecting components for preventive replacement has been developed. It was shown that a level of system reliability could be controlled by changing an order of a quintile function in coordination and a number of redundant objects. A computer simulation model of the system was used to illustrate derived dependencies.
The Man - Machine Type Systems Modeling Approach
Authors: Smalko Zbigniew , Szpytko Janusz 
Published: May 2009

The Man - Machine Type Systems Modeling ApproachThe subject of this paper deals with selected usable characteristics of man - machine systems described by the selected basic attributes. The paper is describing also major objectives of safety engineering, based on the system approach, understanding the structure of safety management system, including the human factor, and all interrelationships between the system components. The part of the paper is example of safety engineering implementations in practice.
Rbf Neural Networks for Function Approximation in Dynamic Modelling
Authors: Nedbalek Jakub 
Published: May 2009

Rbf Neural Networks for Function Approximation in Dynamic ModellingThe paper demonstrates the comparison of Monte Carlo simulation algorithm with neural network enhancement in the reliability case study. With regard to process dynamics, we attempt to evaluate the tank system unreliability related to the initiative input parameters setting. The neural network is used in equation coefficients calculation, which is executed in each transient state. Due to the neural networks, for some of the initial component settings we can achieve the results of computation faster than in classical way of coefficients calculating and substituting into the equation.
Aging Processes as a Primary Aspect of Predicting Reliability and Life of Aeronautical Hardware
Authors: Żurek Józef , Niezgoda Tadeusz , Zieja Mariusz 
Published: May 2009

Aging Processes as a Primary Aspect of Predicting Reliability and Life of Aeronautical Hardware
The forecasting of reliability and life of aeronautical hardware requires recognition of many and various destructive processes that deteriorate the health/maintenance status thereof. The aging of technical components of aircraft as an armament system proves of outstanding significance to reliability and safety of the whole system. The aging process is usually induced by many and various factors, just to mention mechanical, biological, climatic, or chemical ones. The aging is an irreversible process and considerably affects (i.e. Reduces) reliability and life of aeronautical equipment.
Assessment of the Level of Undesirable Actions of People Involved in Road Transport Systems and their Environments.
Authors: Woropay Maciej , Bojar Piotr , Szubartowski Mirosław 
Published: May 2009

Assessment of the Level of Undesirable Actions of People Involved in Road Transport Systems and their Environments.
Road transport systems are socio-technical systems of the type Human - Technical object- Environment <H-TO-E>. In these systems hazards can be caused by: the man C, the technical object OT, and influence of the environment on the technical object and people who are present in the system and its environment. The authors of the paper make an attempt to evaluate the level of threats resulting from intended or not intended actions of people situated in this environment.
Fetal nondopaminergic neural implants in parkinsonian primates
Authors: Bankiewicz Krzysztof S. , Plunkett Robert J. , Jacobowitz David M. , Kopin Irwin J. , Oldfield Edward H. 
Published: May 2009

✓ Implantation of fetal dopamine-containing tissue into preformed cavities in the caudate nucleus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian monkeys leads to behavioral recovery. Recovery may be related to two sources of dopamine: the grafted cells and/or the sprouted fibers from host dopaminergic neurons. The authors undertook this study to determine whether behavioral recovery requires release of dopamine by the implanted tissue, and to establish if nondopaminergic fetal central nervous system implants can induce sprouting of dopamine fibers in the primate brain and cause behavioral recovery.
Rhesus monkeys with MPTP-induced hemiparkinsonism or full parkinsonism and a stable neurological deficit were used for this study. Cavities were created in the caudate nuclei anterior to the foramen of Monro via an open microsurgical approach. Fetal cerebellum or spinal cord was implanted into the preformed cavities of three monkeys. Control parkinsonian monkeys showed no recovery. However, implant-induced improvement was stable for up to 6 months after implantation. Sprouted dopaminergic fibers oriented from the ventral striatum and nucleus accumbens were found in the area of the tissue implant in the animals that received fetal grafts but were not present in the control monkeys.
It is concluded that brain implants do not need to contain dopamine to induce functional recovery in MPTP-induced parkinsonian primates. Implant-induced and trophic factor-mediated dopaminergic sprouting by the host brain plays a role in the behavioral recovery and may well be responsible for the clinical improvement seen in parkinsonian patients after brain implants.
Dorsal root ganglionectomy for failed back surgery syndrome: a 5-year follow-up study
Authors: North Richard B. , Kidd David H. , Campbell James N. , Long Donlin M. 
Published: May 2009

✓ Dorsal root ganglionectomy has been suggested as a method for the treatment of chronic intractable radicular pain, with theoretical advantages over dorsal rhizotomy, which does not interrupt ventral root afferents. The indications for these procedures in patients with persistent pain following lumbosacral spine surgery are not well established. Long-term results have been reported infrequently, and no published series has a mean follow-up period of more than 30 months.
The authors have reviewed their experience with a series of 13 patients with failed back surgery syndrome, in whom dorsal root ganglionectomy was performed. Patients were selected on the basis of clinical presentation and diagnostic root blocks suggesting a monoradicular pain syndrome. Follow-up data were obtained at a mean of 5.5 years following dorsal root ganglionectomy. Follow-up interviews to assess outcome were conducted by a disinterested third party. Treatment “success” (at least 50% sustained relief of pain and patient satisfaction with the result) was recorded in two patients at 2 years after surgery and in none at 5.5 years. Equivocal success (at least 50% relief, without clearcut patient satisfaction) was recorded in one patient at 2 and at 5.5 years postoperatively. Improvements in activities of daily living were recorded in a minority of patients. Loss of sensory and motor function was reported frequently by patients. A minority of patients had reduced or eliminated analgesic intake. These results suggest that dorsal root ganglionectomy has a limited role in the management of failed back surgery syndrome, and that methods to select patients to receive this procedure should be refined or alternative approaches should be considered.
Benign spinal nerve sheath tumors: their occurrence sporadically and in neurofibromatosis types 1 and 2
Authors: Halliday Andrea L. , Sobel Raymond A. , Martuza Robert L. 
Published: May 2009

✓ Benign spinal nerve sheath tumors (neurofibromas and schwannomas) often occur on dorsal nerve roots sporadically or in neurofibromatosis types 1 and 2. These are histologically benign tumors, and distinction between them is frequently not made by clinicians. To determine if there is a correlation between the histological pattern of benign spinal nerve sheath tumors and the type of neurofibromatosis, the clinical and pathological features of these tumors (86 surgical specimens and five autopsies) in 68 patients were reviewed. The patients were classified into one of four categories: neurofibromatosis type 1, neurofibromatosis type 2, uncertain, or sporadic.
The diagnostic criteria used for neurofibromatosis types 1 and 2 were established by the National Institutes of Health. Patients who did not fulfill criteria for either neurofibromatosis type 1 or 2 but who had multiple nervous system tumors or other stigmata of neurofibromatosis were designated “uncertain.” Spinal nerve sheath tumors were considered sporadic in 42 cases (40 schwannomas and two neurofibromas). In the 14 patients with neurofibromatosis type 1, all spinal nerve sheath tumors were neurofibromas. In six of the seven patients with neurofibromatosis type 2, all spinal nerve sheath tumors were schwannomas. One patient with neurofibromatosis type 2 had a spinal nerve sheath schwannoma and a tumor with features of both tumor types.
The authors conclude that spinal nerve sheath tumors in patients with neurofibromatosis type 1 are neurofibromas. In contrast, spinal nerve sheath tumors occurring in neurofibromatosis type 2 or sporadically are most frequently schwannomas. The distinct histological features of these tumors may reflect different pathogenetic mechanisms even though they arise at identical sites in neurofibromatosis types 1 and 2.
Biological significance of tissue plasminogen activator content in brain tumors
Authors: Sawaya Raymond , Rämö O. Juhani , Shi Mei Lin , Mandybur George 
Published: May 2009

✓ Fresh brain-tumor samples were obtained at operation and analyzed for their content of tissue type plasminogen activator (tPA) using an activity assay (gel chromatography zymogram) and an enzyme-linked immunospecific assay. The specimens were taken from 23 glioblastomas, 35 metastatic tumors, 42 meningiomas, 16 low-grade gliomas, and seven acoustic neurinomas; seven specimens were from normal brain.
A strong correlation was found between the results of the two assays (r = 0.77, p < 0.0001). There was a threefold difference in the tPA content of the benign tumors as compared to malignant tumors (p = 0.0006), the latter having less tPA. Histologically benign meningiomas contained higher tPA than malignant meningiomas (p = 0.01); however, the difference between low-grade gliomas and high-grade gliomas was less evident. Overall regression analysis data have shown an inverse relationship between the tissue content in tPA and the presence and degree of tumor necrosis and peritumoral brain edema (p = 0.004 and p = 0.0004, respectively). This finding was most consistent in the glioblastoma group where the correlation coefficient values were r = 0.53 and r = −0.55, respectively. There was no significant correlation between the tissue tPA content and the age and sex, steroid use, or plasma tPA of the patients or the duration of symptoms.
In summary, this is the first demonstration of tPA in a large series of human brain tumors and in normal brain. The differences observed have clear biological significance and, although the source of tPA in tumor tissue is still unknown, a relative reduction in tPA in tumor tissue may play an integral role in the development of tissue necrosis and tissue edema. The lack of tPA in tumor necrosis was not due to tissue destruction and cell death since urokinase was readily detectable in that tissue.
Giant carotid-ophthalmic artery aneurysms: direct clipping utilizing the “trapping-evacuation” technique
Authors: Tamaki Norihiko , Kim Shigekuni , Ehara Kazumasa , Asada Masahiro , Fujita Katsuzo , Taomoto Katsushi , Matsumoto Satoshi 
Published: May 2009

✓ The authors have devised a “trapping-evacuation” technique to facilitate direct clipping of giant aneurysms in the paraophthalmic region of the internal carotid artery (ICA). The giant aneurysm is collapsed by first trapping the aneurysm by temporary occlusion of the cervical common carotid and external carotid arteries, along with temporary clipping of the intracranial ICA distal to the aneurysm. Thereafter, intra-aneurysmal blood is simultaneously aspirated through a catheter placed in the cervical ICA. Exposure of the proximal end of the aneurysm neck is mandatory for successful clipping. This is accomplished by extensive unroofing of the optic canal, removal of the anterior clinoid process, opening of the anterior part of the cavernous sinus, and exposure of the most proximal intradural (C2) and genu (C3) portions of the ICA.
Four cases of giant aneuryms of the paraophthalmic ICA were successfully treated by this technique and the postoperative outcome was good in all cases. Preoperative magnetic resonance imaging for evaluation of the anatomical details, balloon occlusion test of the ICA, and intraoperative measurement of cortical blood flow were important to the success of the operation. Intraoperative digital subtraction angiography via the catheter placed in the cervical ICA was useful in confirming successful clipping.
Sequential magnetic resonance imaging following stereotactic radiofrequency ventralis lateralis thalamotomy
Authors: Tomlinson Frank H. , Jack Clifford R. , Kelly Patrick J. 
Published: May 2009

✓ Serial postoperative magnetic resonance (MR) studies were obtained in 21 patients who underwent somatotopically placed stereotactic radiofrequency (rf) ventralis lateralis thalamotomy for the control of movement disorders. The MR studies were reviewed to determine the MR characteristics of early-phase (≤ 7 days) and late-phase (8 days to 5 months) lesions. Surgery was performed for the control of parkinsonian tremor (14 cases), intention tremor (six cases), and essential tremor (one case). Single rf lesions were made with an electrode (1.6 mm in diameter, 3 mm in tip length) heated to 78°C for 60 seconds. On MR images of the lesions, three distinct concentric zones were identified, described as follows (from the center outward). Zone 1 gives increased signal on long-relaxation time (TR) (T2-weighted) MR images in early- and late-phase lesions and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. Zone 2 gives decreased signal on long-TR (T2-weighted) images in early- and late-phase lesions; it gives isointense signal on short-TR (T1-weighted) images in early-phase lesions only. Zone 3 gives increased signal on long-TR (T2-weighted) images in early-phase lesions only and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. It is considered that in early-phase lesions, Zone 2, with a mean diameter of 7.3 mm on axial long-TR (T2-weighted) imaging, represents an area of hemorrhagic coagulation necrosis. In late-phase lesions, Zone 2, with a mean diameter of 5.0 mm on axial long-TR (T2-weighted) imaging, represents hemosiderin deposition. Zone 3 likely represents edema, and this zone disappears between the early and late periods.
From regression analysis, lesion size began to stabilize at approximately 7 months with a mature lesion diameter of 3.3 mm. Long-term follow-up monitoring (median 16 months) showed good tremor control. Based on clinical and radiological findings, the authors conclude that forms of hemoglobin are suitable markers to assess the size of rf lesions. Serial MR imaging provides a noninvasive means of studying the evolution of rf thalamotomy lesions.