Shopping Center Saved by Short Aggregate Piers

We were faced with an extraordinary geotechnical challenge; our client wanted to support large tilt wa11 buildings and pavements for a 32 acre Commercial Shopping Center on 5 to 8 feet of saturated, I lo 3 blow/foot hydraulically placed fill. To make matters more difficult, the site was in the seismically active Napa Valley. We offered 3 solutions; 2 conventional, and 1 unconventional. Our conventional solutions consisted of: 1) piers founded in the normally consolidated clay below the hydraulic fill, or, 2) over-excavation and replacement of the upper 5 to 8 feet of highly unstable soil. Our unconventional solution consisted of Short Aggregate Piers (Geopier or SAP) to mitigate settlement for moderate building loads. Because of economics, speed and fear of the unknown over-excavation costs, our client chose Geopiers to support the large buildings

Measurement of Vibration and Noise During the Installation of Rammed Aggregate Piers

The objective of the study was to record and evaluate ground vibration and noise generated during the installation of rammed aggregate piers (RAPs). Summarized are ground vibration and noise induced by the ramming equipment (i.e. the hydraulic break hammer and rammer) during the installation of forty-five RAPs at a single site. Data were collected during the entire installation process for each pier, which allowed for the measurement of ground vibration and noise levels for periods when the ramming equipment was positioned at different depths within the RAP. Measurements were also taken at different horizontal distances from the ramming equipment and RAP being installed. The entire data set consists of over 160 ground vibration measurements and over 260 noise measurements. Peak ground velocities measured during the study ranged between approximately 0.5 and 15 millimeters per second for horizontal distances ranging between 1.5 and 10.5 meters. Corresponding vibration frequencies ranged between approximately 20 and 60 Hz. Measured noise levels ranged between approximately 82 and 111 dBA for measurement locations between approximately 1.5 and 10.5 meters from the hammer. Overall, these measured ground vibrations and noise levels are moderate in nature and below those typically generated during pile driving

Liquefaction Mitigation of Three Projects in California

Ground displacements resulting from earthquake-induced soil liquefaction and dynamic densification can cause moderate to severe structural damage during and after an earthquake. Geotechnical construction methods of mitigating these potential ground displacements include mass excavation and replacement with engineered fill, ground improvement such as soil mixing, jet grouting, compaction piers, vibro compaction, vibro stone columns, and deep dynamic compaction, or deep foundations such as driven piles. The ground improvement methods rely on altering the soil properties to resist the seismically-induced shear stresses and soil grain redistribution while deep foundation methods bypass liquefiable soil deposits to found in deeper competent soil or rock. This paper presents an advancement in displacement ground improvement methods used to control soil liquefaction potential by driving highly compacted aggregate into the soil deposit. The ground improvement is accomplished by driving a pipe mandrel to displace the soil mass, backfilling the cavity with select aggregate, and compacting the aggregate in controlled lifts utilizing vertical, vibratory driven methods to further displace and densify the soil deposit while creating a dense Rammed Aggregate Pier®. Specifically the ground improvement method 1) reinforces the soil deposit to resist and re-distribute seismic shear stresses, 2) increases the density and horizontal stress of the surrounding soil, and 3) provides a gravel drain to enhance dissipation of seismicallyinduced excess pore water pressure in the soil. Several projects performed in California, in areas of high seismic activity, have been tested for the resulting shear reinforcement effects and increased density effects manifested by this advanced method of construction. These projects and their resulting field test results are presented and discussed

Characterization of frequency drift of sampled-grating DBR laser module under direct modulation

The authors demonstrate the drift in frequency of a static sampled-grating distributed Bragg reflector (SG DBR) laser module when it is subjected to direct modulation. The magnitude of drift and its settling time is characterized as a function of the index of modulation. Results show that when the directly modulated SG DBR is optically filtered, as in a dense wavelength- division- multiplexed system, a power penalty of 6.7 dB is incurred in comparison to the unfiltered case

Debt income and mental disorder in the general population

Background The association between poor mental health and poverty is well known but its mechanism is not fully understood. This study tests the hypothesis that the association between low income and mental disorder is mediated by debt and its attendant financial hardship. Method The study is a cross-sectional nationally representative survey of private households in England, Scotland and Wales, which assessed 8580 participants aged 16–74 years living in general households. Psychosis, neurosis, alcohol abuse and drug abuse were identified by the Clinical Interview Schedule – Revised, the Schedule for Assessment in Neuropsychiatry (SCAN), the Alcohol Use Disorder Identification Test (AUDIT) and other measures. Detailed questions were asked about income, debt and financial hardship. Results Those with low income were more likely to have mental disorder [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.68–2.59] but this relationship was attenuated after adjustment for debt (OR 1.58, 95% CI 1.25–1.97) and vanished when other sociodemographic variables were also controlled (OR 1.07, 95% CI 0.77–1.48). Of those with mental disorder, 23% were in debt (compared with 8% of those without disorder), and 10% had had a utility disconnected (compared with 3%). The more debts people had, the more likely they were to have some form of mental disorder, even after adjustment for income and other sociodemographic variables. People with six or more separate debts had a six-fold increase in mental disorder after adjustment for income (OR 6.0, 95% CI 3.5–10.3). Conclusions Both low income and debt are associated with mental illness, but the effect of income appears to be mediated largely by debt

Blunted perception of breathlessness in three cases of low grade insular-glioma

Better understanding of breathlessness perception addresses an unmet clinical need for more effective treatments for intractable dyspnoea, a prevalent symptom of multiple medical conditions. The insular-cortex is predominantly activated in brain-imaging studies of dyspnoea, but its precise role remains unclear. We measured experimentally-induced hypercapnic air-hunger in three insular-glioma patients before and after surgical resection. Tests involved one-minute increments in inspired CO2, raising end-tidal PCO2 to 7.5 mmHg above baseline (38.5 ± 5.7 mmHg), whilst ventilation was constrained (10.7 ± 2.3 L/min). Patients rated air-hunger on a visual analogue scale (VAS). Patients had lower stimulus–response (2.8 ± 2 vs. 11 ± 4 %VAS/mmHg; p = 0.004), but similar threshold (40.5 ± 3.9 vs. 43.2 ± 5.1 mmHg), compared to healthy individuals. Volunteered comments implicated diminished affective valence. After surgical resection; sensitivity increased in one patient, decreased in another, and other was unable to tolerate the ventilatory limit before any increase in inspired CO2.We suggest that functional insular-cortex is essential to register breathlessness unpleasantness and could be targeted with neuromodulation in chronically-breathless patients. Neurological patients with insula involvement should be monitored for blunted breathlessness to inform clinical management

Opening the Woods: Towards a Quantification of Neolithic Clearance Around the Somerset Levels and Moors

Environmental reconstructions from pollen records collected within archaeological landscapes have traditionally taken a broadly narrative approach, with few attempts made at hypothesis testing or formal assessment of uncertainty. This disjuncture between the traditional interpretive approach to palynological data and the requirement for detailed, locally specific reconstructions of the landscapes in which people lived has arguably hindered closer integration of palaeoecological and archaeological datasets in recent decades. Here we implement a fundamentally different method for reconstructing past land cover from pollen records to the landscapes of and around the Somerset Levels and Moors — the Multiple Scenario Approach (MSA) — to reconstruct land cover for a series of 200-year timeslices covering the period 4200–2000 cal BC. Modelling of both archaeological and sediment chronologies enables integration of reconstructed changes in land cover with archaeological evidence of contemporary Neolithic human activity. The MSA reconstructions are presented as a series of land cover maps and as graphs of quantitative measures of woodland clearance tracked over time. Our reconstructions provide a more nuanced understanding of the scale and timing of Neolithic clearance than has previously been available from narrative based interpretations of pollen data. While the archaeological record tends to promote a view of long-term continuity in terms of the persistent building of wooden structures in the wetlands, our new interpretation of the palynological data contributes a more dynamic and varying narrative. Our case study demonstrates the potential for further integration of archaeological and palynological datasets, enabling us to get closer to the landscapes in which people lived

A 10Gbps optical burst switching network incorporating ultra-fast (5ns) wavelength switched tunable laser sources

This paper outlines the development of a prototype optical burst mode switching network based upon a star topology, the ultimate application of which could be as a transparent payload processor onboard satellite repeaters. The network architecture incorporates multiple tunable laser sources, burst mode receivers and a passive optical router (Arrayed Waveguide Grating). Each tunable optical signal should carry ≥10Gbps and be capable of wavelength switching in c. 5ns timescales. Two monolithic tunable laser types, based upon different technologies, will be utilised: a Slotted Fabry Perot laser (a Fabry Perot laser with slots added in order to introduce controlled cavity perturbations); and a Modulated Grating Y-Branch Laser (MGY: a widely tunable, multi-section device similar to the DBR laser). While the Slotted Fabry Perot laser is expected to achieve the required switching times, it is an immature technology not yet capable of achieving tunability over 80 ITU channels from a single chip. The MGY device is a more mature technology and has full C-band ITU channel coverage, but is not capable of the required short switching times. Hence, in order to facilitate the integration of this more mature technology into the prototype breadboard with the requisite switching time capabilities, a system of ‘dual laser’ transmitters is being developed to enable data transmission from one MGY laser while the other switches and vice-versa. This work is being performed under ESA contract AO 1-5025/06/NL/PM, Optical Technologies for Ultra - fast Processing

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes