Horizontal Cone Research Articles

Quality Assessment of Periapical Radiographs Taken by Dental Assistants Using the Recent Faculty of General Dental Practice (FGDP) Guidelines.

Periapical radiographs play a pivotal role in dentistry, offering invaluable insights essential for various dental procedures. This study aims to systematically assess the quality of intraoral periapical (IOPA) radiographs evaluating adherence to the recent guidelines established by the Faculty of General Dental Practice (FGDP). A cross-sectional study was conducted at the University College of Dentistry (UCD), employing a non-probability consecutive sampling technique to acquire a calculated sample of 300 IOPA radiographs from the operative, oral surgery, and oral radiology departments. Two senior faculty members evaluated the radiographs according to the recent two-tier grading system outlined in the FGDP guidelines. The study revealed that 197 (65.67%) of the assessed radiographs were diagnostically acceptable, while 103 (34.33%) were deemed diagnostically unacceptable. Contrast problems emerged as the most prevalent issue, accounting for 85 (28.3%) of the cases. Other common problems included incorrect film positioning in 66 (22%), incorrect vertical cone angulation in 37 (12.3%), incorrect horizontal cone angulation in 11 (3.7%), and incorrect processing in 15 (5%) of the IOPA radiographs. This study revealed that approximately two-thirds of the IOPA radiographs were deemed diagnostically acceptable. However, contrast issues emerged as the predominant concern affecting image quality. These findings highlight the critical importance of continuous quality improvement initiatives in radiographic practices to enhance diagnostic precision and ensure optimal patient care.

Effects of non-Darcy mixed convection over a horizontal cone with different convective boundary conditions incorporating gyrotactic microorganisms on dispersion

This paper investigates the influence of dispersion impact on mixed convection flow over a horizontal cone within a non-Darcy porous medium. Multiple convective boundary conditions are applied to address the heat, mass and motile microorganism transfer phenomena. This paper incorporates the dispersion effect for gyrotactic microorganisms due to biological and environmental applications. By imposing appropriate similarity transformations, the nonlinear partial differential equations governing flow, temperature, concentration, and microbe fields are reduced to a system of ordinary differential equations & then solved using the MATLAB BVP4C function. The computation of grid independence test is analyzed for different flow profiles to show the precision of the points. In a few instances, our present numerical data is compared with previously published works, leading to excellent agreement. The non-Darcy effect, as well as mixed convection values from 0.1 to 0.9 and buoyancy parameters from 0.2 to 0.8, all significantly affects the velocity profile. The reduction in the microorganism profile is brought on by the increase in the bioconvection Lewis parameter and bio convection peclet number between 0.3 and 1. In the absence of dispersion, the variation of Biot numbers between 0.5 and 2, favor heat, mass, and motile microorganism transfer the most in the range of mixed convection parameter 0.5 to pure forced convection 1. Thermal, solutal and microorganism dispersion coefficients a, b, c that lie between frac{1}{7} and frac{1}{3} and higher values of modified peclet number ranges from 2 to 10 cause increased dispersion effects which lower flow transfer rates mostly in forced convection regime.

Distinguishing craniomorphometric characteristics and severity in metopic synostosis patients

The decision about which metopic synostosis patients should undergo surgery remains controversial. Multiple measures for radiographic severity have been developed in order to determine the optimal criteria for treatment. The aim of this study was to perform an extensive craniomorphometric analysis of patients who underwent surgery for metopic synostosis to validate and compare the various severity scales developed for this non-syndromic craniosynostosis. A comparative morphometric analysis was performed using computed tomography scans of preoperative metopic synostosis patients (n=167) and normal controls (n=44). Measurements included previous and newly developed metopic severity indices. Volumetric and area analyses were used to determine the degree of anterior cranial area and potential volume restrictions. Of the severity indices measured, the frontal angle, endocranial bifrontal angle (EBF), adjusted EBF (aEBF), anterior cranial fossa angle, horizontal cone angle, and bitemporal/biparietal distance ratio were significantly different in the metopic subjects relative to controls overall. However, metopic index, orbital rim angle, foramen ovale distance, and cranial volume exhibited no significant difference from controls. Only the frontal angle and aEBF correlated with the changes in anterior cranial dimensions observed in metopic synostosis. In conclusion, the frontal angle and aEBF provide the most accurate measures of severity in metopic synostosis.

Lumped‐parameter‐based electromagnetic transients simulation of non‐uniform single‐phase lines using state variable method

The characteristic impedance of a transmission line, a wire or a conductor changes in a non-uniform manner if the distance to the ground at all points longitudinally is not the same. Vertical conductors, transmission towers and sagging overhead lines are examples for the non-uniform lines. In this study, lumped-parameter-based state variable representation of the single-phase non-uniform line is described. From the lumped-parameter non-uniform line model a linear set of first-order differential equations is obtained in the form of state equations and this analytical expression is solved in closed form using MATLAB to obtain the transient response directly in the time domain. The closed-form solution has the advantage of obtaining the response of the system at an instant without the need for data in the previous states except for the initial conditions. The method also allows attaining the voltage and current profile of the system for any instant. In the illustrative cases presented, the systems with different surge impedance variations are considered and the surge response of a vertical conductor, an exponential line, and a horizontal cone and a vertical cone with constant and also varying propagation velocity are computed. The results are verified by those obtained using s-domain simulations of distributed-parameter transmission line and inverse Laplace transform.

Comprehensive Craniomorphometric Analysis of 167 Patients With Metopic Craniosynostosis

BACKGROUND: Metopic craniosynostosis is the second most common form of single suture synostosis, associated with a trigonocephalic head shape. Due to physiologic closure of the metopic suture in infancy, controversy persists regarding the most accurate method to assess severity. The goal of this study was to compare and validate previously described and newly developed measurements of severity for trigonocephaly. Additionally, a new severity scale was proposed to help guide clinical decision making. METHODS: Morphometric analysis using Materialise-Mimics was performed on preoperative CT scans of infants with metopic synostosis and control age-matched infants. Measurements included endocranial bifrontal angle (EBF), adjusted endocranial bifrontal angle (aEBF), frontal angle, anterior fossa angle, metopic index, horizontal cone angle, temporal depression angle, foramen ovale distance, and bitemporal/biparietal distance ratio. Volumetric and area analyses of the frontal cranium were conducted to determine the degree of restriction in the metopic cohort. Preoperative electroencephalogram (EEG) data were compared for a subset of metopic patients to assess whether the proposed severity scale has neurodevelopmental implications. Results were analyzed using an independent sample t test, Pearson’s correlation coefficient, and receiver operating characteristic curve analysis. RESULTS: Analyses were performed for 167 patients with metopic synostosis (mean age 7.2 ± 4.9 months), and compared with 44 control subjects (mean age 7.6 ± 7.6 months). The EBF, aEBF, frontal angle, anterior fossa angle, horizontal cone angle, and bitemporal/biparietal ratio were all significantly smaller in the metopic cohort compared with the control cohort (P < 0.05).The metopic index, temporal depression angle, and foramen ovale distance were not significantly different from the control cohort. Metopic skulls demonstrated a significantly decreased anterior cranium area (average, 2466.12 mm2; P < 0.001) and significantly increased anterior-posterior (AP) length (average, 4.00 mm; P = 0.003) and craniocaudal length of the anterior cranium (average, 6.41 mm; P = 0.01) compared with control skulls. There was a significant negative correlation between the anterior cranial area and both the vertical length and AP length. The frontal angle significantly correlated with the increases in vertical height and AP length, whereas the aEBF correlated with only the AP length. Other measurements did not significantly correlate with changes in anterior calvarium dimensions. Receiver operating characteristic curve analysis identified a frontal angle of 101.3° as the diagnostic threshold between operated metopic synostosis and normal skulls. Sixteen metopic subjects with existing EEG data were evaluated. Six patients with frontal angles more acute than the diagnostic threshold exhibited significantly attenuated EEG signals compared with controls (P = 0.037). Patients with frontal angles greater than the diagnostic threshold did not exhibit any significant change in their EEG compared with controls. CONCLUSIONS: In the largest radiographic series of metopic synostosis patients to date, this study examined the validity of measurements for severity of metopic craniosynostosis. The frontal angle provides the strongest correlation with growth compensation in the most severe cases of trigonocephaly. Furthermore, a severity classification using the frontal angle correlates with preoperative EEG analysis. The bitemporal/biparietal ratio, metopic index, cranial volumes, cranial base structures, and orbital structures should be reconsidered as measures of metopic severity as they are either nonconcordant with the anterior-cranium compensatory changes or not significantly different from control.

Abstract 149: Distinguishing Craniomorphometric Characteristics And Severity In 100 Metopic Synostosis Patients

Purpose: Metopic craniosynostosis is the second most common form of single suture synostosis. Controversy persists regarding the most accurate method for assessing severity in trigonocephaly. This study aimed to develop a robust diagnostic measurement system for reproducible severity assessment in trigonocephaly. In addition, it aimed to identify a severity scale to distinguish between mild, moderate, and severe metopic patients. Methods: Morphometric analysis using Materialise Mimics was performed on preoperative CT scans of infants with metopic craniosynostosis. Assessed indices of trigonocephaly were endocranial bifrontal angle, frontal angle, posterior angle of the anterior cranial fossa, brow ridge to eurion ratio, horizontal orbital cone angle, temporal depression angle, orbital rim angle, and interdacryon distance. Inter- and intra-rater reliability were established with two independent reviewers per patient. Results were analyzed using a Pearson’s correlation coefficient. Furthermore, age-based sub group analysis was performed between <6 months (group 1) and >6 months (group 2) using an unpaired T-test. Results: One hundred patients with metopic craniosynostosis were included in the analysis. The majority were male (82%) with a mean age of 6.6 months. The endocranial bifrontal angle ranged from 112.9 to 148.0 with a mean of 127.0. The frontal angle ranged from 83.2 to 109.3 with a mean of 98.3. Strong correlations existed between the frontal angle, posterior angle of anterior cranial fossa, horizontal cone angle, orbital rim angle, metopic index (bitemporal distance/biparietal distance), and upper orbital width (Pearson coefficient > 0.3 for all). Additionally, the posterior angle of anterior cranial fossa strongly correlated with zygomaticofrontal suture distance, interdacryon distance, and lateral orbital width. Changes in the endocranial bifrontal angle were associated with changes in the lateral orbital width, but there were no other correlations found between the endocranial bifrontal angle and the other measurements. Age-based subgroup analysis showed that there was no significant difference between measurements of severity between group 1 and group 2. Conclusion: In the largest radiographic series of metopic synostosis patients to date, concordance of measures was identified between the frontal angle, posterior angle of anterior cranial fossa, horizontal cone angle, orbital rim angle, metopic index, and upper orbital width. These measurements represent reliable measures for trigonocephaly assessment. Furthermore, we found that there is no significant difference in severity based on age.

Strabismus in Unicoronal Craniosynostosis: Effect of Orbital Dysmorphology and Fronto-Orbital Advancement and Remodeling.

The purpose of this study was to determine what craniometric changes occur to both orbits of unicoronal craniosynostosis patients undergoing fronto-orbital advancement and remodeling, and which of these changes are associated with new onset of postoperative strabismus. A retrospective analysis was performed of the preoperative and postoperative orbits of 24 unicoronal craniosynostosis patients and the orbits of 24 control subjects, totaling 144 orbits. Eight parameters were evaluated using multivariate logistic regression analysis. One of the parameters was modified orbital index, an indicator of severity of harlequin deformity. Significant differences in orbital dimensions and angles were present bilaterally in unicoronal craniosynostosis orbits when compared to controls. Fronto-orbital advancement and remodeling increased the ipsilateral unicoronal craniosynostosis orbital volume from 13,184 ± 2003 mm to 16,220 ± 2323 mm (p < 0.001). Ipsilateral horizontal cone angles were increased from 48 ± 5 degrees to 54 ± 7 degrees (p = 0.004). Ipsilateral vertical cone angles were decreased from 73 ± 8 degrees to 66 ± 10 degrees (p = 0.003). Ipsilateral modified orbital index improved from 0.83 ± 0.06 to 0.88 ± 0.06 (p = 0.003). Three of the 19 unicoronal craniosynostosis patients developed transient postoperative strabismus. Logistic regression analysis displayed a strong significant association between new-onset strabismus and a change in modified orbital index with a coefficient of 30.84 ± 14.51 (p < 0.05). The orbital dysmorphology in unicoronal craniosynostosis is bilateral in nature, and it is not wholly treated with conventional fronto-orbital advancement and remodeling. The severity of ipsilateral orbital dysmorphology is correlated with the incidence of postoperative strabismus following conventional fronto-orbital advancement and remodeling. Future research is needed to develop strategies to mitigate the risk of development of strabismus in this group of patients. Risk, III.

S6A-07 SESSION 6A: CORONAL SYNOSTOSIS SEVERITY OF ORBITAL DYSMORPHOLOGY CORRELATES WITH STRABISMUS IN UNICORONAL CRANIOSYNOSTOSIS PATIENTS UNDERGOING FRONTAL ORBITAL ADVANCEMENT

Introduction: The purpose of this study is to determine what craniometric changes occur to both orbits of unicoronal craniosynostosis (UCS) undergoing frontal orbital advancement and remodeling (FOAR) and which of these changes are associated with new onset of postoperative strabismus. Methods: A retrospective analysis of pre and postoperative 24 UCS orbits and 24 control orbits were analyzed, totaling 144 orbits. Eight parameters were evaluated utilizing multivariate logistic regression analysis: orbital volume, horizontal and vertical cone angles, orbital depth, corneal projection, orbital rim height and width, as well as modified orbital index (MOI). MOI is an indicator of severity of Harlequin deformity. Results: Significant differences in orbital dimensions and angles were present bilaterally in UCS orbits when compared to controls. FOAR increased the ipsilateral UCS orbital volume from 13,183.93 ± 2,003.45mm to 16,220.43 ± 2,322.54mm (p<0.001). Ipsilateral horizontal cone angles were increased from 48.49 ± 5.24° to 53.50 ± 6.51° (p=0.004). Ipsilateral vertical cone angles were decreased from 73.27 ± 8.00° to 66.23 ± 9.62° (p=0.003). Ipsilateral MOI improved from 0.83 ± 0.06 to 0.88 ± 0.06 (p=0.003). Contralaterally, orbital volume also improved to 15,670.33 ± 1,988.17mm (p<0.001), a 13.4% increase. Three of the nineteen UCS patients (15%) developed transient postoperative strabismus, which resolved with eye patching. The majority of patients developed postoperative strabismus with an MOI change of greater than 20%. Logistic regression analysis displayed a significant association between new-onset strabismus and a change in MOI with a coefficient of 30.84 ±14.51 (p<0.05). Conclusion: This is the first craniometric study evaluating the association between three dimensional changes incurred by UCS orbits undergoing FOAR and strabismus. The orbital dysmorphology in UCS is bilateral in nature, and it is not wholly treated with conventional FOAR. Severity of ipsilateral orbital dysmorphology is correlated with incidence of postoperative strabismus following conventional FOAR. An ipsilateral MIO change of greater than 20% would seem to suggest that the greater the correction of Harlequin deformity may be associated with FOAR-induced strabismus. We can hypothesize those who require more radical correction, i.e. had a more severe preoperative orbital dysmorphology, are at increased risk for developing strabismus. Our methodology precludes determination of causality, but the correlation is strong. Future research is needed to develop strategies to mitigate risk of development of strabismus in this group of patients.

Extended Shearlet-Based Image Watermarking Algorithm Using Selective Coefficients in Horizontal Cone

In this paper, a novel image watermarking method in extended shearlet domain is proposed. Since extended discrete shearlet transform is an effective multi-scale and multi-direction analysis method, it can not only provide nearly optimal description of image content, but also explicitly decompose a given image into directional components. In the presented scheme, the extended discrete shearlet transform is first applied on the host image and extended discrete shearlet transformed subimages are studied. Then, the optimum subimages are selected using the information entropy; subsequently, the watermark bits are embedded by modifying the selective shearlet coefficients of selected subbands in horizontal cone, and scrambling and spread spectrum technique are also used in the embedding process. The experimental results demonstrate that our scheme has good imperceptibility and good robustness against common attacks, such as cropping, JPEG compression and rotation attacks.

Repetition of Examination Due to Motion Artifacts in Horizontal Cone Beam CT: Comparison among Three Different Kinds of Head Support.

Aims and Objectives:The aim of this study was to evaluate the repetition rate of examination due to motion artifacts in horizontal cone beam computed tomography, using three different kinds of head support, with reference to the patient's age. Further purpose was to evaluate how comfortable head supports were.Materials and Methods:Seven hundred and fifty patients underwent a maxillofacial/dental arches volumetric imaging scan. They were divided into three groups depending on the head support used: foam headrest, foam headrest with head strap, and head restraint helmet. Each group was subdivided into three age groups: ≤18-year-old, 19–65-year-old, and ≥66-year-old patients. A severity index of motion artifacts, divided into four tiers from absence to remarkable artifacts, was adopted. Finally, each patient gave their judgment about the head support comfort by a questionnaire including ten yes/no questions. A three-score scale (insufficient, sufficient, and good) was used to judge the comfort. Collected data were analyzed using the SPSS® version 23.0 statistical analysis software.Results:Forty-one patients (5.4%) repeated the examination. In 16 (2.1%), 15 (2.0%), and 10 (1.3%) of them, foam headrest, foam headrest with head strap, and head restraint helmet were used, respectively. Examination was repeated in 5.3%, 3.8%, and 10.6% in ≤18-year-old, 19–65-year-old, and ≥66-year-old patients, respectively. Patients almost always judged good the comfort for each kind of support. The lowest percentage of satisfaction was observed for the headrest with head strap and was judged good in 78% of the cases.Conclusions:The repetition rate of examination showed similar values among the foam headrest, foam headrest with head strap, and head restraint helmet in under 66-year-old patients. In over 65-year-old patients, the head restraint helmet obviously decreased the repetition rate of examination. All three head supports were good comfort, especially the foam headrest.

Image Watermark Based on Extended Shearlet and Insertion Using the Largest Information Entropy on Horizontal Cone

Extended discrete shearlet provides a directional multiresolution decomposition. It has been mathematically shown that extended discrete shearlet is a more efficient representation for the signals containing distributed discontinuities such as edges, compared to discrete wavelet. Multiresolution analyses such as curvelet and ridgelet share similar properties, yet their directional representations are significantly different from that of extended discrete shearlet. Taking advantage of the unique properties of directional representation of extended discrete shearlet, we develop an image watermark algorithm based on the largest information entropy. In proposed algorithm, firstly, 1-level extended discrete shearlet transform decomposes the test image into directional components on horizontal cone; each directional component reflects directional features and textured features differently. Next, the directional component whose information entropy is the highest is selected to carry watermark. Compared with related algorithms based on DWT and DCT, the proposed algorithm tends to obtain preferable invisibility when it is robust against common attacks.

An Evaluation of Ramp Control Signal Head Placement Based on Motorist's Cone of Visions

Roadside mounted ramp control signals have one upper head, and one lower head in California. The upper head is intended for use by the approaching motorists, while the lower one for use by the stopped motorists. Complaints have been received regarding the visibility of these signal heads. The evaluation presented in this paper is to mathematically analyze the visibility of these signal heads on a tangent roadway alignment based on satisfactory motorists' cones of vision. Roadway design, signal placement, and driver characteristics are integrated into one analytic framework. The results indicated that the horizontal satisfactory cone of vision controls the placement design. To meet the 20 degree satisfactory horizontal cone of vision as specified by the Manual on Uniform Traffic Control Devices (MUTCD), a ramp control signal head has to be placed a minimum of 13.3 m downstream of the limit line.

Review on Domestic and International Flammability Test Methods of Textile

Domestic and international testing methods of flammability property of textile, such as oxygen index method, vertical test method, 45 degree test method, horizontal test method and cone calorimeter method, were analyzed via comparing the principles, as well as their requirements of different acts and standards. To comprehensively evaluate the burning behavior of textiles, appropriate combination of methods should be chosen according to the practical application.

The development of fine-grained sensitivity to eye contact after 6 years of age

Adults use eye contact as a cue to the mental and emotional states of others. Here, we examined developmental changes in the ability to discriminate between eye contact and averted gaze. Children (6-, 8-, 10-, and 14-year-olds) and adults (n=18/age) viewed photographs of a model fixating the center of a camera lens and a series of positions to the left/right or upward/downward and judged whether the model’s gaze was direct or averted to the left/right or upward/downward. The horizontal range of fixation positions leading to the perception of direct gaze (the cone of gaze) was more than 50% larger in 6-year-olds than in adults, but it was adult-like and smaller than the vertical cone of gaze by 8years of age. The vertical cone of gaze was large and statistically adult-like by age 6, with only a small linear reduction thereafter. In all age groups, the horizontal cone of gaze was centered on the bridge of the participant’s nose and the vertical cone was centered slightly below the participant’s eye height. These findings indicate that until after age 6, relatively poor sensitivity to direct versus averted gaze limits children’s ability to use gaze cues to make social judgments.

Natural Convection on a Horizontal Cone in a Porous Medium with Non-Uniform Wall Temperature/Concentration or Heat/Mass Flux and Suction/Injection

The steady natural convection flow on a horizontal cone embedded in a saturated porous medium with non-uniform wall temperature/concentration or heat/mass flux and suction/injection has been investigated. Non-similar solutions have been obtained. The nonlinear coupled differential equations under boundary layer approximations governing the flow have been numerically solved. The Nusselt and Sherwood numbers are found to depend on the buoyancy forces, suction/injection rates, variation of wall temperature/concentration or heat/mass flux, Lewis number and the non-Darcy parameter.

Retinal Regulation

The horizontal cells in the outer plexiform layer of the retina generate the surround inhibition for the bipolar cells, but the underlying mechanism has remained elusive. Kamermans et al. show that there are gap junction hemichannels at synapses between horizontal cells and cone photoreceptors. Blockade of these hemichannels by carbenoxolone causes horizontal-cell hyperpolarization and disrupts feedback responses in cones and horizontal cells. This finding suggests the existence under physiological conditions of a negative-feedback mechanism from horizontal cells to cones through an electrical or ephatic mechanism. M. Kamermans, I. Fahrenfort, K. Schultz, U. Janssen-Bienhold, T. Sjoerdsma, R. Weiler, Hemichannel-mediated inhibition in the outer retina. Science 292 , 1178-1180 (2001). [Abstract] [Full Text]

Inaccuracies Associated with Estimating Random Measurement Errors

This paper examines a commonly used procedure, proposed by Baecher, for separating the random measurement error associated with a particular test from the inherent spatial variability of the geological material. By comparing the two techniques of random field theory and geostatistics it is shown that the method, while well founded, requires a number of factors to be investigated before conclusions can be made regarding the random measurement error of a particular test. These factors include the nugget effect, the sample spacing, and the stationarity of the data. Two case studies are presented that are based on closely spaced data derived from a series of vertical and horizontal cone penetration tests performed in a relatively homogeneous, overconsolidated clay. The sensitivity of the results obtained from the procedure of Baecher is tested with regard to the degree of trend removed from the data and the spacing of the samples in the data set.

Measurement accuracy: a comparison of two intra-oral digital radiographic systems, RadioVisiography-S and FlashDent, with analog film.

To compare the accuracy of measurement algorithms incorporated into the software provided with two CCD-based digital radiographic systems and compare assessments using intra-oral film. A test object with three radiopaque reference points was imaged using Ektaspeed intra-oral film, both with and without an overlaid 1 mm reference grid, the RVG-S, the measurement software of which overlays a 2 mm grid, and the FlashDent, which uses a mouse-driven cursor to estimate distances. Geometric factors, including source-to-object and receptor-to-object distances, vertical and horizontal cone angulation, and vertical angulation of receptor, were successively altered. Six viewers estimated vertical, horizontal and diagonal distances for each image. Increased source-to-object distance resulted in a 5-10% reduction in image dimensions, whereas increased receptor-to-object distance produced a magnification of 15-20% with all techniques. Increased vertical and horizontal cone angulation resulted in slight increases in magnification (0-5%) whereas greater receptor angulation resulted in noticeable magnification under all test conditions (10-15%). Estimated values for vertical, horizontal and diagonal measurements were approximately 5-10% higher than the actual dimensions, irrespective of the technique used. The FlashDent mouse-driven cursor system and direct measurement of distances from conventional film were more accurate in horizontal and diagonal dimension estimates than using an overlaid grid. Intra-observer and inter-observer differences were found for specific situations. The mouse-driven computerized measurement cursor and intra-oral film assessment using a ruler provided the most accurate, reliable and consistent dimensional measurements.

Fish-protecting functions of water treatment machines in water supply systems of thermal and nuclear power plants

1. More than a decade of operation of water-cleaning machines with a conical net has demonstrated their good technical and economic characteristics as regards failure-free operation and water-cleaning performance. 2. After a simple modification, the existing water-cleaning machines with a vertical axis of cone rotation can perform a fish-protecting function. 3. For larger water consumers (such as water supply systems of thermal and nuclear power plants) machines with a horizontal cone rotation axis are recommended (so-called directflow water-cleaning machines). With some modernization of the flowthrough component, water offtake facilities can ensure bypass and survival of over 90% of young fish without building any expensive fish guard structures. 4. Instead of fish guard facilities planned to be built at operating thermal and nuclear power plants, one should consider the possibility of removing the existing water-cleaning machines with flat nets and installing machines with conical nets.

Production From Horizontal Wells After 5 Years

The first of four horizontal wells drilled by Elf Aquitaine during the last years produced its first barrel of oil in Aug. 1980. The others followed between 1981 and 1983. There is now enough production history to draw conclusions, some of which are surprising.