A model for the constant-head pumping test conducted in vertically fractured media

An analytical model for the constant-head pumping test is developed for a partially penetrating well that has a finite thickness skin, and intersects a single vertical fracture. In the model, the fracture is fully confined and flow occurs only in the fracture. The model is developed using Laplace transform and finite Fourier transform methods. The model is to be used for analysing well test data from vertically fractured media and for verifying numerical models. Dimensionless curves are used to study the effects of a finite thickness skin and a partially penetrating wellbore. In the presence of a finite thickness skin, or a partially penetrating wellbore, a typical flow response for the constant-head pumping test has three distinct periods of flow corresponding to small-, intermediate- and large-time. Small- and large-time approximations are presented for the model. For tests where the wellbore is fully penetrating, or the partial penetration ratio is known, these approximations can be used to analyse field data.     

BATSE/OSSE rapid burst response

The BATSE and OSSE instrument teams have modified flight software to promptly (within 2 min of trigger) slew the OSSE detectors to burst locations determined on-board by BATSE. This enables OSSE to make sensitive searches for prompt and delayed post-burst line and continuum emission above 50 keV. In the best cases our sensitivity will be more than an order of magnitude better than any other search in this energy range. We expect to slew to 1–2 bursts per month, based on the OSSE FOV and BATSE event rate. Detections or limits from continued operation of this system may provide significant constraints on burst models. As an example of the observations made using this system, we present preliminary limits for post-burst emission from GRB 950223 on several time scales.     

Deterioration Of Quality Of Groundwater From Suani Wellfield,Tripoli, Libya 1976–93

The Suani wellfield, consisting of 52 pumping wells, is located about six kilometers south of Tripoli and its continuously pumped to supply the city of Tripoli with public supplies. In 1976, total disolved-solids content ranged from 265-675 mg/l; however, sea water has moved inland as a result of heavy exploitation of the Miocene-Quaternary aquifer in order to meet the increasing water demand. Dissolved-solids content now exceeds 10,000 mg/l. RÉSUMÉ: Le champ captant de Suani, composé de 52 puits de pompage, est situé à environ 6 km au sud de Tripoli; le pompage continu est destiné à l'adduction d'eau potable de Tripoli. En 1976, la minéralisation de l'eau variait entre 265 et 675 mg/l. La surexploitation de l'aquifère mio-quaternaire a provoqué une intrusion de l'eau de mer, du fait de l'accroissement de la consommation. La minéralisation de l'eau atteint maintenant 10 g/l. RESUMEN: El campo de pozos de Suani, situado a unos 6 kilómetros al sur de Trípoli, presenta 52 pozos de extracción que son bombeados de forma continua para el abastecimiento de dicha ciudad. En 1976, el contenido total de sólidos disueltos oscilaba entre 265-675 mg/l. Sin embargo, se ha producido un proceso de intrusión de agua marina como resultado de la sobreexplotación del acuífero Miocénico-Cuaternario para absorbar la creciente demanda de agua. El contenido de sólidos disueltos alcanza ahora un valor superior a los 10000 mg/l.     

Direct mid-IR images of Gl 2591,W51-IRS2 and S140

We present the results of direct mid-IR images of the luminous young stellar objects GL 2591, S140-IRS1, and W51-IRS2. The sources show an extended mid-IR emission at the limit of our spatial resolution indicating the presence of dense circumstellar dust disks.     

The Relationship of Green-Line Transients to White-Light Coronal Mass Ejections

We report observations by the Large Angle Spectrometric Coronagraph (LASCO) on the SOHO spacecraft of three coronal green-line transients that could be clearly associated with coronal mass ejections (CMEs) detected in Thomson-scattered white light. Two of these events, with speeds >25 km s^-1, may be classified as ‘whip-like’ transients. They are associated with the core of the white-light CMEs, identified with erupting prominence material, rather than with the leading edge of the CMEs. The third green-line transient has a markedly different appearance and is more gradual than the other two, with a projected outward speed <10 km s^-1. This event corresponds to the leading edge of a ‘streamer blowout’ type of CME. A dark void is left behind in the emission-line corona following each of the fast eruptions. Both fast emission-line transients start off as a loop structure rising up from close to the solar surface. We suggest that the driving mechanism for these events may be the emergence of new bipolar magnetic regions on the surface of the Sun, which destabilize the ambient corona and cause an eruption. The possible relationship of these events to recent X-ray observations of CMEs is briefly discussed. Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1004981125702