Modified dispersion relations and the response of the rotating Unruh-DeWitt detector

We study the response of a rotating monopole detector that is coupled to a massless scalar field which is described by a non-linear dispersion relation in flat spacetime. Since it does not seem to be possible to evaluate the response of the rotating detector analytically, we resort to numerical computations. Interestingly, unlike the case of the uniformly accelerated detector that has been considered recently, we find that defining the transition probability rate of the rotating detector poses no difficulties. Further, we show that the response of the rotating detector can be computed {\it exactly}\vee (albeit, numerically) even when it is coupled to a field that is governed by a non-linear dispersion relation. We also discuss the response of the rotating detector in the presence of a cylindrical boundary on which the scalar field is constrained to vanish. While super-luminal dispersion relations hardly affect the standard results, we find that sub-luminal dispersion relations can lead to relatively large modifications.Comment: V1: 11 pages, 3 figures; V2: 12 pages, 3 figures, considerably revised, we now calculate the detector response exactly; V3: 14 pages, 3 figures, minor changes, to appear in Phys. Rev.

Naked Singularity Formation In f(R) Gravity

We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scalar as $f({\mathcal R})=\alpha{\mathcal R}^{m}$, we show that for an appropriate initial value of the energy density, if $\alpha$ and $m$ satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the time behavior of the Kretschmann scalar. Also, as long as parameter $\alpha$ obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration.Comment: 15 pages, 4 figures, to appear in GR

Performance of the CMS High Granularity Calorimeter prototype to charged pion beams of 20−-300 GeV/c

The upgrade of the CMS experiment for the high luminosity operation of the LHC comprises the replacement of the current endcap calorimeter by a high granularity sampling calorimeter (HGCAL). The electromagnetic section of the HGCAL is based on silicon sensors interspersed between lead and copper (or copper tungsten) absorbers. The hadronic section uses layers of stainless steel as an absorbing medium and silicon sensors as an active medium in the regions of high radiation exposure, and scintillator tiles directly readout by silicon photomultipliers in the remaining regions. As part of the development of the detector and its readout electronic components, a section of a silicon-based HGCAL prototype detector along with a section of the CALICE AHCAL prototype was exposed to muons, electrons and charged pions in beam test experiments at the H2 beamline at the CERN SPS in October 2018. The AHCAL uses the same technology as foreseen for the HGCAL but with much finer longitudinal segmentation. The performance of the calorimeters in terms of energy response and resolution, longitudinal and transverse shower profiles is studied using negatively charged pions, and is compared to GEANT4 predictions. This is the first report summarizing results of hadronic showers measured by the HGCAL prototype using beam test data.Comment: To be submitted to JINS

Evaluation of dum palm kernel activated carbon in chromium and lead adsorption from synthetic waste water

This study aimed at the co-current removal of chromium and lead ions from synthetic waste water using dum palm kernel activated carbon. The adsorption experiment was conducted by varying time, pH and concentrations of the simulated solution. The data obtained were analyzed, and the best conditions for the uptake were at pH of 6, equilibrium time of 40 minutes. The two best isotherms models for the adsorption system were Sip, and Dubinin–Radushkevich, models respectively. Based on the Temkin adsorption energy calculated as 9.5793 and 0.4997 J/mol, the uptake of lead and chromium were chemisorption and physico-sorption, respectively. The maximum uptake calculated from Dubinin–Radushkevich plots were 14.1696 and 7.7191 mg/g, for lead and chromium, respectively.International Journal of Environment Vol.5(3) 2016, pp.104-118</p

Recovery of Proteins and Chromium Complexes from Chromium – Containing Leather Waste (CCLW)

Chromium – Containing Leather Waste (CCLW) constitutes an environmental pollution problem to leather industries disposing the waste by landfill. The waste mainly consists of collagen and chromium III complexes. This work is a design of reactors to recover gelatin, polypeptides and chromium from CCLW. The results of the experiment shows that 68% of protein, based on dry weight of leather scraps, could be recovered. Three reactors with a total volume of 18 m3 was designed to handle 10,431 kg of waste generated from the tanning industries

Development of Rating Curve for River Ngadda

Accurate river discharge estimation is critical for sustainable water resource management and infrastructure design, especially in areas where data scarcity is a major concern. This study addresses this issue by developing a rating curve for the Ngadda River in Borno State, Nigeria. The lack of continuous discharge data and reliable rating curves has historically hindered water resource project planning in the region. Leveraging stage-discharge rating curves and utilizing an optimization-based technique with Excel solver, curve parameters were calibrated to accurately depict the hydraulic relationship between river stage and discharge. The analysis of discharge data at Logojeri and Maiduguri gauging stations revealed seasonal changes in river flow, emphasizing the importance of continuous monitoring for effective water resource management. Correlation analysis between actual and predicted discharge confirmed the reliability of the developed rating curve, while uncertainty analysis revealed insights into potential errors associated with the discharge estimation. The developed rating curve which is for the two specific gauging stations (Maiduguri and Logojeri), provides a useful tool for converting stage data into discharge values, thereby assisting with water resource planning and decision-making. It is therefore urged for ongoing monitoring efforts and the installation of monitoring tools to modify and improve the developed rating curve's ability to capture the dynamic hydrological behavior of the Ngadda River

The influence of admixtures on the strength and linear expansion of cement-stabilized phosphogypsum

The effect of admixture content, dry density and curing condition on linear expansion of cement-stabilized phosphogypsum (CSPG) was studied over a ninety-day period. The phosphogypsum was stabilized using 8% Type I portland cement. Cylindrical CSPG specimens (51mm × 102 mm) were fabricated by static compaction (ASTM D 698) at three density levels: standard Proctor maximum dry density (13.7 kN/m ) and 5% on either side of this density with a moisture content (20%) corresponding to the maximum standard Proctor dry density. CaCl (1% and 2%) and Daraset (0.05% and 0.15%) as a percentage of the amount of cement, were added to CSPG. Curing conditions were (at ambient temperature): open to air, moisture-controlled and soaked. Selected specimens were analyzed by derivative thermogravimetry and scanning electron microscopy. When cured under moisture-controlled environment, CSPG had a short initial period of expansion irrespective of the dry density or admixture content. Increasing dry density led to a period of contraction following expansion. At the same dry density, the additon of CaCl led to a period of no length change while the addition of Daraset led to more initial expansion. The length change, over time, of air-cured CSPG specimens was negligible. The correlation between ettringite content and expansion was crude. For soaked specimens, ettringite growth was widespread and unusually high. Compacted at the lowest density (13.0 kN/m ) and cured in moisture-rich environments, CSPG deteriorated significantly. 3 3 2

Outcome of Cerebral Venous Thrombosis Requiring Mechanical Ventilation

Background: Patients with cerebral venous thrombosis (CVT) requiring mechanical ventilation (MV) may have a severe procoagulant state, extensive venous sinus thrombosis, and a worse outcome, but there is a paucity of studies on this topic. We compare the clinical risk factors, radiological findings, and outcomes between CVT patients requiring MV and the non-MV group. Methods: Consecutive CVT patients admitted to our service were included. Their clinical details, prothrombotic states and MRI and MRV findings were noted. The patients were admitted to the intensive care unit (ICU) if the Glasgow Coma Scale (GCS) score was below 14 and intubated if arterial blood gas analysis was abnormal. All the patients received heparin followed by an oral anticoagulant. In-hospital death was noted, and functional outcomes at 3 months were assessed using the modified Rankin Scale (mRS). Results: Ninety-eight patients with CVT were admitted during the study period; 45 (45.9%) required ICU care, and 18 of them required MV for a median of 6.5 (1&ndash;15) days. The MV patients had a shorter duration of illness, a lower GCS score, and protein C deficiency. Twelve (12.2%) patients died: five (27.8%) in the MV, four (14.8%) in the non-MV ICU, and three (5.7%) in the non-MV non-ICU groups. Poor outcomes were 5.5%, 14.8%, and 5.7%, respectively. On Cox regression analysis, the MV had an association with death [adjusted hazard ratio (AHR) 0.40, 95% confidence interval 0.21&ndash;0.77; p = 0.007] and poor outcome at 3 months (AHR 0.45, 95% CI 0.27&ndash;0.76; p = 0.003). Conclusions: About 18.4% of CVT patients require MV with a mortality of 27.8%. Amongst the survivors, 90.7% of patients have a good outcome at 3 months