Noninverting integrators with improved high-frequency response

Two methods are presented for improving the poor high-frequency response of noninverting integrators due to the limited gain-bandwidth product of operational amplifiers (o.a.s). Integrators involving two o.a.s can be upgraded by choosing the inverter's resistance ratio in correspondence with the golden section. Furthermore, a known method for compensating Miller integrators is applied to the DeBoo integrator.     

Experimentelle Untersuchungen zur Barytübersättigung einer Thermalsole

On the basis of thermodynamical modelling it was proves that pressure and temperature variations may induce precipitation of barite, anhydrite/gypsum and celestite in geothermyl power plants. The precipitation dynamics of earth-alkaline sulfates has been investigated in a column experiment simulating in-situ conditions for pressure, temperature, and salinity (216 g/l). In this paper we describe the experimental setup for simulating pressures up to 250 bar and high temperatures in a sandstone core. Additional precipitation experiments confirmed the expected second-orer reaction for the precipitation of barite at a medium rate of 2.5 · 10 ^?4 l · mg ^?1 · h ^?1 . The experiments show that the solubility of barite (2.5 mg/l Ba and 450 mg/ISO ₄ ) is higher than the model forecast. Precipitation of celestite and anhydrite/gypsum was not observed. During the column experiments with a sandstone core under in-situ conditions no precipitation of barite, anhydrite/gypsum and celestite took place.     

Comparative studies of the psychosomatic aspects of liver diseases

Connections between disturbed functions of liver and mental diseases at all times have been generally supposed as existent and have been discussed in the literature; they should be clarified by means of questionnaire-tests: MPI-test and MMQ-test of Eysenck combined with neurotizism-depression-questionnaire of Hoffmann-La Roche allowed to comprehend the dimensions of personality "neurotizism" and "depressivity". Concerning "neurotizism" statistically significant differences could be found between liver-patients and healthy persons in a tendency to a significant increase among liver-patients, but not between liver-patients with other diseases. The tendency to "depressivity" of healthy persons could be statistically evaluated as being much greater than that of liver-patients; there were no differences between liver-patients and patients with other diseases. That is why liver-patients do not differ psychically from patients suffering from other diseases; they share their reaction to the occurrence of disease - in various degrees until a neurotic lack of active realization of the fact of illness. Liver-diseases apparently are not triggered or caused by special pre-morbid alterations.     

A GaAs HEMT MMIC chip set for automotive radar systems fabricatedby optical stepper lithography

A 77 GHz automotive radar system for collision avoidance and intelligent cruise control has recently gained interest because of its huge market potential. The questions of the optimum technological and system approaches leading to both low cost and high performance have not yet been finally answered. The approach to this problem reported here differs mainly in two aspects from the GaAs monolithic microwave integrated circuit (MMIC) solutions described earlier: (1) 0.12 μm gatelength pseudomorphic high electron mobility transistors (PHEMTs) are fabricated by optical stepper lithography, (2) a coplanar design is used. A fully passivated PHEMT MMIC fabrication process is reported with current-gain and power-gain cutoff frequencies exceeding 115 and 220 GHz, respectively. The design and performance of a chip set consisting of four different MMICs [voltage controlled oscillator (VCO), harmonic mixer, transmitter, receiver] are described. The great potential of this MMIC approach to meet all system requirements of an automotive radar sensor in a cost-effective and production-oriented way is shown. To our knowledge, this is the first demonstration of W-band coplanar multifunctional MMICs fabricated by optical stepper lithography     

Determination of Some Beer Flavours by Stir Bar Sorptive Extraction and Solvent Back Extraction

This work presents the development of a simple, rapid and low cost method for the determination of some beer flavours as esters such as isoamyl acetate, ethyl caproate, ethyl caprylate, phenyl acetate, ethyl caprate, phenylethyl acetate, ethyl laurate, ethyl myristate and ethyl palmitate using stir bar sorptive extraction (SBSE). The combination of this extraction technique with solvent back extraction and subsequent gas chromatographic analysis with flame ionisation detection was used for the determination of these compounds. The effects of different mixtures of organic solvents and the influence of sampling time and time of solvent back extraction were studied. An optimum procedure for the SBSE method was developed. The method had high repeatability (RSD 2.1–7.3%), good linearity (the correlation coefficients were higher than 0.9995 for quadratic fit over the concentration range from 0.015 to 30 mg/L) and acceptable recoveries (78–107%) and precision (RSD > 7.3%).     

How to park freight trains on rail–rail transshipment yards: the train location problem

In modern rail–rail transshipment yards huge gantry cranes spanning all railway tracks allow for an efficient transshipment of containers between different freight trains. This way, multiple trains loaded with cargo for varying destinations can be consolidated to a reduced number of homogeneous trains, which is an essential requirement of hub-and-spoke railway systems. An important problem during the daily operations of such a transshipment yard is the train location problem, which assigns each train of a given pulse to a railway track (vertical position) and decides on each train’s parking position on the track (horizontal position), so that the distances of container movements are minimized and the overall workload is equally shared among cranes. For this problem a mathematical model is presented; different heuristic solution procedures are described and tested in a comprehensive computational study. The results show that our procedures allow for a remarkable reduction of train processing time compared with typical real-world train location policies.     

Fourier Transform Infrared Microscopy—a Tool for Speciation of Impactor-Sampled Single Particles or Particle Clusters

With the recent advent of Fourier transform infrared (FTIR) microscopy, a powerful new tool has been added to the methods available for integrated dust analysis (IDA). While the intrinsic molecular specificity of infrared spectroscopy was applied in the 1970s with the IDA strategy of impactor-sampled aerosol analysis, at that time only average information from at least two impactor spots (1–10 μg range) could be obtained after sample preparation by grinding with KBr. This preparation step for heavily loaded samples, which may induce secondary reactions within the particles and destroy part of the reactive (acidic) species originally present, is no longer required with the new technique. FTIR microscopy allows the direct observation of isolated particles (>5 μm diameter) or particle clusters (<5 μm diameter) impacted on KBr or ZnSe (by the transmission technique) after a typical sampling duration of 5 minutes in an urban environment. This technique not only shows significant superiority in the quality of the spectra obtained but also is the key to preservation of original particle acidity. By this technique inhomogeneities within one impactor spot could be shown clearly (compound mapping). Several source, city, and background aerosols have been analyzed in the micro domain for the first time for NH₄ ⁺ compounds, nitrates, sulfates, silicates, carbonates, and organics (aliphatic esters and aromatics). Acidic sulfates have been found in garage samples but not in city aerosols so far. By comparing samples at room temperature and heated up to 150°C, further information on the NH₄ ⁺ compounds and the volatility of the species could be obtained. The adaptation of millisecond-time resolution of the new rapid-scan FTIR spectrometer in our laboratory for molecular specific thermal analysis research (MOSTAR) has been started, extending the capabilities of previous work.     

3-dimensional MR coronary angiography with navigator technique: imaging of the proximal course of a coronary artery anomaly

Severe congestive heart failure (CHF) is associated with Cheyne-Stokes (C-S) respiration, which may be an index of poorer prognosis. The mechanisms linking C-S respiration to poorer functional status and prognosis in patients with CHF are unknown. We tested the hypothesis that C-S respiration increases muscle sympathetic nerve activity (MSNA) in 9 patients with CHF. Oxygen saturation was 96 +/- 1% during normal breathing and 91 +/- 1% after the apneic episodes (p < 0.05). Mean blood pressure was 79 +/- 8 mm Hg during normal breathing and 85 +/- 8 mm Hg during C-S respiration (p = 0.001). C-S respiration increased MSNA burst frequency (from 45 +/- 5 bursts/min during normal breathing to 50 +/- 5 bursts/min during C-S respiration; p < 0.05) and total integrated nerve activity (to 117 +/- 7%; p < 0.05). We also studied an additional 5 patients in whom C-S breathing was constant, without any periods of spontaneous normal breathing. In these patients, MSNA was higher (65 +/- 5 bursts/min) than MSNA in patients in whom C-S breathing was only intermittent (45 +/- 5 bursts/min; p < 0.05). In all 14 patients, the effects of different phases of C-S respiration were examined. MSNA was highest during the second half of each apnea (increasing to 152 +/- 14%; p < 0.01) and blood pressure was highest during mild hyperventilation occurring after termination of apnea (p < 0.0001). We conclude that C-S respiration decreases oxygen saturation, increases MSNA, and induces transient elevations in blood pressure in patients with CHF.     

Just-in-sequence material supply—a simulation based solution in electronics production

Just-in-time and just-in-sequence (JIS) concepts have been presented by the automotive industries in the past years. Today, where customer-oriented manufacturing is more and more demanded, electronics production is in a similar situation. The integral organizational means at Diehl AKO Nuremberg have been realized to achieve JIS material supply in the electronics sector. The right cooperation of software solutions from SAP (ERP), LES (logistics) to BOFOS (manufacturing planning) results in a set of improvements in material flow, scheduling, and document flow. The following paper shows the concepts, realizations, and achievements of the partners Diehl AKO and ETL. The main interest lies on the general approach, not on a particular detail.