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PubMed2001

Analysis of material and energy flow in sewage treatment facilities in Japan.

Energy consumption in sewage treatment facilities in Japan has increased due to increasing tap water consumption. To reduce the resource/energy consumption in sewage treatment facilities, measures such as the selection of optimum treatment processes and operating conditions should be considered. The objective of this study is to gather information necessary for the determination of optimum sewage treatment processes and optimum operating conditions. The energy consumption and material flow in sewage treatment facilities in Japan are analyzed using statistical data. In 1994, reuse rate of treated sewage outside the treatment facilities in Japan was 18% of the amount of domestic treated water. In this regard, reuse of water outside facilities should be encouraged. Average electric power consumption per unit volume of wastewater in sewage treatment facilities varies widely from facility to facility and closely correlates with the facility scale. For example, the smaller the facility scale, the larger the electric power consumption. Treatment volume of sewage in smaller facilities is much less than their capacity. 3.7 million t year-1 of dehydration cake is incinerated and 0.1 million t year-1 of it is converted by composting. The recycle rate of the cake was low. Developing a new sludge treatment process other than incineration is necessary.

Conservation of Natural Resources↗

PubMedDate not supplied

The "response" in behavior theory.

The term "response" is a basic one in behavior theory, particularly reflex theory, but its definition is not clear. The origin of the term in the common vocabulary has affected its later extensions in the analysis of behavior. Some contemporary theorists accept the existence of two "types" of response, coordinating one with the Pavlovian conditioning procedure, the other with the operant conditioning procedure of the so-called "contingent" variety. Reservations are expressed here about such distinctions between response classes and conditioning paradigms, emphasizing the difficulties that arise from certain conventions and inadequacies in current definitions and conceptions of "response". The critical nature of the problem for behavior theory is illustrated once again by the recent laboratory finding that a familiar and accepted conditional reflex, that of the "conditioned cardiac CR," can be fractionated into "parts" and is therefore perhaps no longer to be treated as a single unitary "response".

Animals↗

PubMed2003

Application of a depolymerization model for predicting thermochemical hydrolysis of hemicellulose.

Literature data were collected and analyzed to guide selection of conditions for pretreatment by dilute acid and water-only hemicellulose hydrolysis, and the severity parameter was used to relate performance of different studies on a consistent basis and define attractive operating conditions. Experiments were then run to confirm performance with corn stover. Although substantially better hemicellulose sugar yields are observed when acid is added, costs would be reduced and processing operations simplified if less acid could be used while maintaining good yields, and understanding the relationship between operating conditions and yields would be invaluable to realizing this goal. However, existing models seldom include the oligomeric intermediates prevalent at lower acid levels, and the few studies that include such species do not account for the distribution of chain lengths during reaction. Therefore, the polymeric nature of hemicellulose was integrated into a kinetic model often used to describe the decomposition of synthetic polymers with the assumption that hemicellulose linkages are randomly broken during hydrolysis. Predictions of monomer yields were generally consistent with our pretreatment data, data reported in the literature, and predictions of other models, but the model tended to overpredict oligomer yields. These differences need to be resolved by gathering additional data and improving the model.

Biomass↗

PubMed2003

Biofouling assessment using an infrared monitor.

The paper details the design of an infrared monitor for detecting biofilm accumulation on surfaces in flowing systems. It is based on the principle that the amount of infrared radiation absorbed by a biofilm, is proportional to the amount of biofilm present. The test surface in the monitor has to be transparent in order to allow the passage of the radiation, so that the radiation absorbed is solely due to the presence of the biofilm. Since the biofilm structure is very dependent upon the conditions under which it was formed, e.g. fluid flow, nutrient and cell concentrations and temperature, it cannot be made to give absolute values of biofilm accumulation. Nevertheless the device is extremely useful for comparison purposes, such as the evaluation of biocide efficacy under different operating conditions. Correlations of biofilm thickness with infrared absorbance can be made, however, for specified operating conditions. The value of the monitor is demonstrated in some typical examples. The infrared absorbance shows a clear distinction between the accumulation of biofilm under two different velocity regimes, three pH values and three chlorine concentrations at two water velocities. It is suggested that in addition to laboratory use, the monitor could be used effectively for biofilm control in cooling water circuits.

Biofilms↗

PubMed1995

Spontaneous respiration versus controlled ventilation anaesthesia with halothane for intra-ocular surgery.

One hundred and thirty-seven patients were randomly allocated to receive halothane anaesthesia for intra-ocular surgery either by IPPV (n = 71) or breathing spontaneously (n = 66). Both techniques provided satisfactory operating conditions in 87% and 80% of procedures, respectively. Intra-ocular pressure was reduced in a similar majority of patients, rose in a similar percentage (spontaneous = 11%, controlled = 21%) and remained unchanged in a few. Surgeons' reports of good operative conditions correlated very well with intra-ocular pressure changes whether they rose or fell intra-operatively. The duration of anaesthesia and the time taken to achieve full recovery following the two techniques were similar. Post-operative vomiting, headache, sore throat and confusion occurred with similar frequency, and analgesic and antiemetic requirements were not influenced by the technique. Resumption of ambulation, oral intake and micturation occurred similarly. In both groups, patients with a low normal pre-operative intra-ocular pressure tended to show a rise in intra-ocular pressure during anaesthesia, and those with a high normal pre-operative intra-ocular pressure tended to show a fall.

Anesthesia, Inhalation↗

PubMed1999

Computing operating diagrams of bioreactors.

The operating diagram of a bioreactor is an illustrative way to present the effect that the operating conditions have on its long-term behavior. It can be constructed if a mathematical model of the bioreactor is available. The procedure for constructing the operating diagram consists in analyzing the dynamic behavior of the system of the differential equations of the model. Some methods are described that can be used in computing operating diagrams of bioreactors. They are based on numerical bifurcation techniques for systems of differential equations. Both cases of bioreactors with constant and periodically varying operating conditions are considered.

Bioreactors↗

PubMed2003

Fossil-fueled power plants as a source of atmospheric carbon monoxide.

Elevated carbon monoxide (CO) mixing ratios in excess of those derived from emissions inventories have been observed in plumes from one gas- and coal-fired power plant and three of four lignite coal-fired electric utility power plants observed in east and central Texas. Observations of elevated CO on days characterized by differing wind directions show that CO emissions from the lignite plants were relatively constant over time and cannot be ascribed to separate sources adjacent to the power plants. These three plants were found to be emitting CO at rates 22 to 34 times those tabulated in State and Federal emissions inventories. Elevated CO emissions from the gas- and coal-fired plant were highly variable on time scales of hours to days, in one case changing by a factor of 8 within an hour. Three other fossil-fueled power plants, including one lignite-fired plant observed during this study, did not emit substantial amounts of CO, suggesting that a combination of plant operating conditions and the use of lignite coal may contribute to the enhanced emissions. Observed elevated CO emissions from the three lignite plants, if representative of average operating conditions, represent an additional 30% of the annual total CO emissions from point sources for the state of Texas.

Air Pollutants↗

PubMed1997

Para-umbilical block: a new concept for regional anaesthesia in children.

This preliminary study describes a new technique to provide analgesia in children undergoing umbilical hernia repair. The para-umbilical block consists of infiltrating the anterior cutaneous branches of the two tenth spinal roots over and under the rectus sheath far from the operative field. Intra and postoperative analgesia as well as operative conditions were assessed in 11 children 16.7 +/- 31 months old, weighing 8421 +/- 6941 g, the block being performed before surgery under light general anaesthesia. Intraoperative analgesia, operative conditions and recovery were good in all patients. Analgesia was adequate one h after surgery in ten patients, six h after surgery in eight. The block proved to be safe and on the whole effective in this short series. The study should proceed on a multi-centre basis if possible. Indications can be extended.

Analgesia↗

PubMed2005

Raising and controlling study of dissolved oxygen concentration in closed-type aeration tank.

This study investigated the promotion and control of dissolved oxygen (DO) concentration of the closed-type aeration tank via practical experiments in the wastewater treatment system of a 5-star hotel in Taipei. As with limited and treasured space in Taiwan, before the completion of the sewer system construction in cities, to utilize the mat foundation under large buildings as the space of sewage treatment plant still has been one of the alternatives of those sewage treatments. However, aeration tanks constructed in the mat foundation of buildings have smaller effective water depth, which will cause a lower total transfer amount of DO. Controlling the total exhaust gas flow rate can increase the pressure on such closed-type aeration tanks. The DO concentration thus may increase according to Henry's Law. Furthermore, it may enable operators to adjust the DO concentration of the aeration tank more precisely and thus sustain optimal operating conditions in these treatment facilities. Practical experiments indicated that the DO concentration of aeration tank maintains an average of 3.8 mg l(-1), obtaining the optimum operating conditions. The efficiency of the biological treatment facilities in the mat foundation could be markedly improved.

Bioreactors↗

PubMedDate not supplied

[Indices of detection in integral radiophotographic examinations in rural areas].

Integral radiophotographic detection was carried out in the territories of 5 randomly selected village dispensaries in 5 different counties. The action was performed in strictly operational conditions, without external experimental interferences. Stress was laid on the strict following of the methodological letter concerning radiophotography. The performing of integral radiophotographic detection in strictly operational conditions in the rural environment demonstrated the utility of these examinations in the present stage. The output obtained can be considered as satisfactory; local variations can be noted and this indicates the possibility of differentiating the conduct in various geographical areas.

Humans↗

PubMed1988

Midazolam sedation for outpatient fibreoptic endoscopy: evaluation of alfentanil supplementation.

Alfentanil, a short-acting opioid, was used as an adjuvant to midazolam for sedation of 30 outpatients undergoing upper gastrointestinal endoscopy. The operating conditions and recovery times were compared with those of a similar group of 30 patients sedated with midazolam only. The use of alfentanil resulted in improved operating conditions and a more rapid recovery. Patient acceptance was high.

Adult↗

PubMedDate not supplied

Bioprocess equipment: characterization of energy dissipation rate and its potential to damage cells.

A study was conducted in which analytical, computational, and experimental measurements combined with analysis were made to characterize the local energy dissipation rate in a variety of conditions, vessels, and geometries that animal cells would encounter in typical bioprocessing situations. With no gas-liquid interfaces present, as expected, the local energy dissipation rate is typically orders of magnitude lower than what has been experimentally demonstrated to catastrophically damage typically used, suspended animal cells. However, local energy dissipation rates shown to remove animal cells from microcarriers are achievable under some normal operating conditions and geometries. Whether local energy dissipation rates created under typical operating conditions can have nonlethal effects is still an open question and currently under investigation. Whether the sensitivity of other, nontypical, suspended animal cells such as cells obtained directly from tissue (primary cells) and clusters of cells, such as islets, are more sensitive than the typically used cells is also still under investigation.

Animals↗

PubMed1996

Cadmium analysis in soil by microwave acid digestion and graphite furnace atomic absorption spectrometry.

The need to determine micronutrients and toxic elements in soils has grown in recent years and cadmium is of special interest. A method has been developed for the determination of cadmium in soils based on a prior acid digestion of the samples with nitric acid in closed Teflon vessels, into a microwave over. The cadmium determination was carried out by graphite furnace atomic absorption spectrometry (GFAAS) with L'vov platform. Optimum operating conditions, analyte modifiers and matrix interferences have been investigated. The best matrix modifier was found to be ammonium dihydrogen phosphate. The interferences are greatly reduced under these operating conditions and calibration can be performed with simple aqueous solutions of the metal standard. The method is rapid and provides accurate and precise results that agree with certified values for two reference materials: BCR 141 (calcareous loam soil) and BCR 277 (estuarine sediment).

Journal Article↗

PubMed2006

Equilibria and dynamics of liquid-phase trinitrotoluene adsorption on granular activated carbon: effect of temperature and pH.

Environmental regulations for removal of trinitrotoluene (TNT) from wastewater have steadily become more stringent. This study focuses on the adsorption equilibrium, kinetics, and column dynamics of TNT on heterogeneous activated carbon. Adsorption equilibrium data obtained in terms of temperature (298.15, 313.15 and 323.15K) and pH (3, 8 and 10) were correlated by the Langmuir equation. In addition, the adsorption energy distribution functions which describe heterogeneous characteristics of porous solid sorbents were calculated by using the generalized nonlinear regularization method. Adsorption breakthrough curves were studied in activated column under various operating conditions such as temperature, pH, concentration, flow rate, and column length. We found that the effect of pH on adsorption breakthrough curves was considerably higher than other operating conditions. An adsorption model was formulated by employing the surface diffusion model inside the activated carbon particles. The model equation that was solved numerically by an orthogonal collocation method successfully simulated the adsorption breakthrough curves.

Adsorption↗

PubMed1993

Aortic pressure estimation with electro-mechanical circulatory assist devices.

An adaptive technique for the estimation of the time history of aortic pressure (from applied voltage and position feedback) has been designed, implemented, and bench tested using the Penn State Electric Ventricular Assist Device (EVAD). This method, known in the field of automatic control as a dynamic observer, utilizes gains which were determined using experimental data collected while the EVAD was running on a mock circulatory system. An adaptive scheme provides the observer with a method of changing its initial conditions on a stroke-by-stroke basis which improves observer performance. In both determining the feedback gains and developing the adaptation scheme, a range of beat rates and pressure loads was taken into account to yield satisfactory observer performance over a range of operating conditions. The observer was implemented, its performance was verified in vitro and results are reported. In the six experimental operating conditions, the beat rate ranged from 56-104 beats per minute (bpm) and the span of the mean systolic aortic pressure was 10.7-18.7 kPa (80-140 mmHg). For these cases, the mean deviation between the actual and estimated aortic pressure during the latter two-thirds of systole was 0.41 kPa (3.1 mmHg).

Algorithms↗

PubMed2001

Short-Term and medium-term effects of spinal cord tract transections on soleus H-reflex in freely moving rats.

Spinal cord function is normally influenced by descending activity from supraspinal structures. When injury removes or distorts this influence, function changes and spasticity and other disabling problems eventually appear. Understanding how descending activity affects spinal cord function could lead to new means for inducing, guiding, and assessing recovery after injury. In this study, we investigated the short-term and medium-term effects of spinal cord bilateral dorsal column (DC), unilateral (ipsilateral) lateral column (LC), bilateral dorsal column ascending tract (DA), or bilateral dorsal column corticospinal tract (CST) transection at vertebral level T8-T9 on the soleus H-reflex in freely moving rats. Data were collected continuously for 10-20 days before and for 20-155 days after bilateral DC (13 rats), DA (10 rats), CST (eight rats), or ipsilateral LC (seven rats) transection. Histological examination showed that transections were 98(+/- 3 SD)% complete for DC rats, 80(+/- 20)% complete for LC rats, 91(+/- 13 SD)% complete for DA rats, and 95(+/-13)% complete for CST rats. LC, CST, and DA transections produced an immediate (i.e., first-day) increase in H-reflex amplitude. LC transection also produced a small decrease in background activity in the first few posttransection days. Other than this small decrease, none of the transections produced evidence for the phenomenon of spinal shock. For all transections, all measures returned to or neared pretransection values within 2 weeks. DA and LC transections were associated with modest increase in H-reflex amplitude 1-3 months after transection. These medium-term effects must be taken into account when assessing transection effects on operant conditioning of the H-reflex. At the same time, the results are consistent with other evidence that, while H-reflex rate dependence and H-reflex operant conditioning are sensitive measures of spinal cord injury, the H-reflex itself is not.

Animals↗

PubMedDate not supplied

[Cooperative activity of motor and frontal cortex neurons in trained cats systemically administered M-cholinoreceptor blockers].

It was shown previously that peripherally administered antagonists of the central 1 M-cholinoreceptors led to a selective impairment of bar-pressing response in a food-reinforced operant conditioned task but did not alter contextual behavior and functions such as motivation, perception, and locomotion. To obtain information about the central mechanisms of the conditioning impairment, we recorded simultaneously the extracellular multiunit activity from the frontal and motor neocortical areas of five cats trained to acquisition criteria in a food-reinforced operant conditioning task. Multiunit recordings were performed drur 1) normal conditioning; 2) conditioning during subcutaneous administration of muscarinic antagonists scopolamine (0.03 mg/kg), trihexyphenidyl (1 mg/kg), and methylscopolamine (0.03 mg/kg). Autocorrelation analysis showed that scopolamine and trihexyphenidyl but not methylscopolamine led to a significant increase in the tendency of cortical cells to fire in a cyclic way (i.e., the shift of the firing pattern from a single-spike discharge to burst, rhythmic, or rhythmic-burst discharge) both in the motor and frontal areas. Cross-correlation analysis showed that the bursting and rhythmic-bursting cells synchronized their activity within and (in a number of cases) between the cortical areas. These changes in the neuronal activity within the motor cortex and frontal cortex were accompanied by a significant decrease in the functional connectivity both inside and between the cortical areas in parallel with selective impairment of the conditioned response.

Animals↗

PubMed2003

The fate of chlorine and organic materials in swimming pools.

The fate of organic nitrogen and carbon introduced into a swimming pool by pool users has been studied using a 2.2 m(3) model pool. The study made use of a body fluid analogue (BFA), containing the primary endogenous organic amino compounds, and a soiling analogue represented by humic acid (HA). The system was used to examine the effect of organic loading and organic carbon (OC) sources (i.e. amino or HA) on the levels and speciation of the key chlorinated disinfection by-products of trihalomethanes (THMs) and chloramines under operating conditions representative of those employed on a full-scale pool. Results revealed OC, chloramines and THMs to all attain steady-state levels after 200-500 h of operation, reflecting mineralisation of the dosed OC. Steady-state levels of OC were roughly linearly dependent on dose rate over the range of operational conditions investigated and, as with the chloramine levels recorded, were in reasonable agreement with those reported for full-scale pools. THM levels recorded were somewhat lower than those found in real pools, and were dependent on both on pH carbon source: the THM formation propensity for the soling analogue was around eight times than of the BFA. Of the assayed by-products, only nitrate was found to accumulate, accounting for 4-28% of the dosed amino nitrogen. Contrary to previous postulations based on the application of Henry's Law, only insignificant amounts of the volatile by-products were found to be lost to the atmosphere.

Chlorine Compounds↗