scholarly journals ON THE SQUATTING OF SHIPS IN SHALLOW AND RESTRICTED WATER

1986 ◽  
Vol 1 (20) ◽  
pp. 206
Author(s):  
A.M. Ferguson ◽  
R.C. McGregor

A major feature of the advances in marine technology is the increasing number, size and speed of ships and, consequently, an increased interest in hydrodynamic problems associated with water restricted in depth and/or lateral extent. The transport of dangerous cargoes and their impact on the benefits of resolving the areas of uncertainty. Experience of 1,104 vessels of different flags and trades during 1978, shows that grounding/stranding is the third most frequent cause of damage[1], An examination of the total expenditure of money and time required to repair the resulting damage shows this category to rank highly in both. Indeed, the total repair cost expended as a result of this cause rank top and account for more than l/5th of the total. Although the shipowner bears a large proportion of the cost of lost revenue, grounding represents a significant cost to underwriters, shipowners and port authorities. The continuous increase in size and draught of vessels in relation to water depth ensures that this situation will continue unless there is a radical development in instrumentation. To limit the risk of grounding it is extremely important to be able to predict which of a vessel's extremities will experience the greatest sinkage and ground. Where the underkeel clearance is low, reasonable accuracy is demanded in order to ensure safety and to avoid unduly reducing the earning capacity of the vessel by overcaution. This requires a sound knowledge of a vessel's tendency to 'squat'.

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 29-35 ◽  
Author(s):  
PETER W. HART ◽  
DALE E. NUTTER

During the last several years, the increasing cost and decreasing availability of mixed southern hardwoods have resulted in financial and production difficulties for southern U.S. mills that use a significant percentage of hardwood kraft pulp. Traditionally, in the United States, hardwoods are not plantation grown because of the growth time required to produce a quality tree suitable for pulping. One potential method of mitigating the cost and supply issues associated with the use of native hardwoods is to grow eucalyptus in plantations for the sole purpose of producing hardwood pulp. However, most of the eucalyptus species used in pulping elsewhere in the world are not capable of surviving in the southern U.S. climate. This study examines the potential of seven different cold-tolerant eucalyptus species to be used as replacements for, or supplements to, mixed southern hardwoods. The laboratory pulping and bleaching aspects of these seven species are discussed, along with pertinent mill operational data. Selected mill trial data also are reviewed.


Author(s):  
Temitope Ben-Ajepe ◽  
Ifechukwu Benedict Nwogu ◽  
Damilola Quazeem Olaoye ◽  
Abdulhafeez Ayodele Mustapha ◽  
Theogene Uwizeyimana ◽  
...  

AbstractAfrica as a continent has experienced a continuous increase in the cost of healthcare as its demands increase. With many of these African countries living below the poverty threshold, Africans continue to die from preventable and curable diseases. Population increases have led to an increase in demands for healthcare, which unfortunately have been met with inequitable distribution of drugs. Hence, the outcomes from healthcare interventions are frequently not maximized. These problems notably call for some economic principles and policies to guide medication selection, procurement, or donation for population prioritization or health insurance. Pharmacoeconomics drives efficient use of scarce or limited resources to maximize healthcare benefits and reduce costs. It also brings to play tools that rate therapy choice based on the quality of life added to the patient after a choice of intervention was made over an alternative. In this paper, we commented on the needs, prospect, and challenges of pharmacoeconomics in Africa.


2021 ◽  
Vol 17 (1) ◽  
pp. 260-264
Author(s):  
Alexandru VULPE ◽  
Raluca ANDREI ◽  
Alexandru BRUMARU ◽  
Octavian FRATU

Abstract: With the development of mobile devices and the advent of smartphones, the Internet has become part of everyday life. Any category of information about weather, flight schedule, etc. it is just a click away from the keyboard. This availability of data has led to a continuous increase in connectivity between devices, from any corner of the world. Combining device connectivity with systems automation allows the collection of information, its analysis and implicitly decision-making on the basis of information. Their introduction and continued expansion of devices that communicate in networks (including the Internet) have made security issues very important devices as well as for users. One of the main methodologies that ensures data confidentiality is encryption, which protects data from unauthorized access, but at the cost of using extensive mathematical models. Due to the nature of IoT devices, the resources allocated to a device can be constrained by certain factors, some of which are related to costs and others to the physical limitations of the device. Ensuring the confidentiality of data requires the use of encryption algorithms for these interconnected devices, which provide protection while maintaining the operation of that device. The need for these types of algorithms has created conditions for the growth and development of the concept of lightweight encryption, which aim to find encryption systems that can be implemented on these categories of devices, with limited hardware and software requirements. The paper proposes a lightweight cryptographic algorithm implemented on a microcontroller system, comparing its performances with those of the already existing system (based on x86).


2015 ◽  
Vol 4 (6) ◽  
pp. 82 ◽  
Author(s):  
Julie M. Mhlaba ◽  
Emily W. Stockert ◽  
Martin Coronel ◽  
Alexander J. Langerman

Objective: Operating rooms (OR) generate a large portion of hospital revenue and waste. Consequently, improving efficiency and reducing waste is a high priority. Our objective was to quantify waste associated with opened but unused instruments from trays and to compare this with the cost of individually wrapping instruments.Methods: Data was collected from June to November of 2013 in a 550-bed hospital in the United States. We recorded the instrument usage of two commonly-used trays for ten cases each. The time to decontaminate and reassemble instrument trays and peel packs was measured, and the cost to reprocess one instrument was calculated.Results: Average utilization was 14% for the Plastic Soft Tissue Tray and 29% for the Major Laparotomy Tray. Of 98 instruments in the Plastics tray (n = 10), 0% was used in all cases observed and 59% were used in no observed cases. Of 110 instruments in the Major Tray (n = 10), 0% was used in all cases observed and 25% were used in no observed cases. Average cost to reprocess one instrument was $0.34-$0.47 in a tray and $0.81-$0.84 in a peel pack, or individually-wrapped instrument.Conclusions: We estimate that the cost of peel packing an instrument is roughly two times the cost of tray packing. Therefore, it becomes more cost effective from a processing standpoint to package an instrument in a peel pack when there is less than a 42%-56% probability of use depending on instrument type. This study demonstrates an opportunity for reorganization of instrument delivery that could result in a significant cost-savings and waste reduction.


1992 ◽  
Vol 22 (7) ◽  
pp. 980-983 ◽  
Author(s):  
Richard G. Oderwald ◽  
Elizabeth Jones

Formulas are derived for determining the total number of sample points and the number of volume points for a point, double sample with a ratio of means estimator to replace a point sample and achieve the same variance. A minimum ratio of the cost of measuring volume to the cost of measuring basal area at a point is determined for which the point, double sample will be less costly, in terms of time required to measure points, than the point sample.


Author(s):  
Benjamin R. Hubbard ◽  
Joshua M. Pearce

This study provides designs for a low-cost, easily replicable open source lab-grade digital scale that can be used as a precision balance. The design is such that it can be manufactured for use in most labs throughout the world with open source RepRap-class material extrusion-based 3-D printers for the mechanical components and readily available open source electronics including the Arduino Nano. Several versions of the design were fabricated and tested for precision and accuracy for a range of load cells. The results showed the open source scale was found to be repeatable within 0.1g with multiple load cells, with even better precision (0.01g) depending on load cell range and style. The scale tracks linearly with proprietary lab-grade scales, meeting the performance specified in the load cell data sheets, indicating that it is accurate across the range of the load cell installed. The smallest loadcell tested(100g) offers precision on the order of a commercial digital mass balance. The scale can be produced at significant cost savings compared to scales of comparable range and precision when serial capability is present. The cost savings increase significantly as the range of the scale increases and are particularly well-suited for resource-constrained medical and scientific facilities.


Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 78 ◽  
Author(s):  
M. B. Hastings

We give a quantum algorithm to exactly solve certain problems in combinatorial optimization, including weighted MAX-2-SAT as well as problems where the objective function is a weighted sum of products of Ising variables, all terms of the same degree D; this problem is called weighted MAX-ED-LIN2. We require that the optimal solution be unique for odd D and doubly degenerate for even D; however, we expect that the algorithm still works without this condition and we show how to reduce to the case without this assumption at the cost of an additional overhead. While the time required is still exponential, the algorithm provably outperforms Grover's algorithm assuming a mild condition on the number of low energy states of the target Hamiltonian. The detailed analysis of the runtime dependence on a tradeoff between the number of such states and algorithm speed: fewer such states allows a greater speedup. This leads to a natural hybrid algorithm that finds either an exact or approximate solution.


Author(s):  
Suzanne Tsacoumis

High fidelity measures have proven to be powerful tools for measuring a broad range of competencies and their validity is well documented. However, their high-touch nature is often a deterrent to their use due to the cost and time required to develop and implement them. In addition, given the increased reliance on technology to screen and evaluate job candidates, organizations are continuing to search for more efficient ways to gather the information they need about one's capabilities. This chapter describes how innovative, interactive rich-media simulations that incorporate branching technology have been used in several real-world applications. The main focus is on describing the nature of these assessments and highlighting potential solutions to the unique measurement challenges associated with these types of assessments.


1997 ◽  
Vol 6 (2) ◽  
pp. 215-227 ◽  
Author(s):  
Guy Edjlali ◽  
Gagan Guyagrawal ◽  
Alan Sussman ◽  
Jim Humphries ◽  
Joel Saltz

For better utilization of computing resources, it is important to consider parallel programming environments in which the number of available processors varies at run-time. In this article, we discuss run-time support for data-parallel programming in such an adaptive environment. Executing programs in an adaptive environment requires redistributing data when the number of processors changes, and also requires determining new loop bounds and communication patterns for the new set of processors. We have developed a run-time library to provide this support. We discuss how the run-time library can be used by compilers of high-performance Fortran (HPF)-like languages to generate code for an adaptive environment. We present performance results for a Navier-Stokes solver and a multigrid template run on a network of workstations and an IBM SP-2. Our experiments show that if the number of processors is not varied frequently, the cost of data redistribution is not significant compared to the time required for the actual computation. Overall, our work establishes the feasibility of compiling HPF for a network of nondedicated workstations, which are likely to be an important resource for parallel programming in the future.


2015 ◽  
Vol 93 (7) ◽  
pp. 559-565 ◽  
Author(s):  
Carlos Enrique Chávez-Solís ◽  
Guillermina Alcaraz

Hermit crabs respond to predators by hiding in their shells. However, retraction may cause the crab to lose hold of the rock and fall through the water column, and the crab may land with the shell aperture in a different orientation. When the shell is aperture down, hermit crabs return to activity by moving their bodies forward and placing their legs on the ground. In contrast, when the shell is aperture up, crabs need to perform a righting maneuver by extending part of their bodies out of the shell, which makes them more vulnerable to predation. The main goal of this study was to examine the hiding time of the hermit crab Calcinus californiensis Bouvier, 1898 in different shell species under these two different situations to better understand the conflict between the cost of staying in hiding and the risk of predation. The study was conducted in rocky tide pools using seven different shell types that reflect different predator protection and resource value to the crab (based on previous studies). We measured the time required to perform the righting maneuver as a measure of the potential risk incurred when returning to activity. The hiding time with the shell aperture down was not affected by shell species. The requirement to carry out a righting maneuver lengthened the hiding time, which varied in the different shell species according to the time required to recover the natural position. The potential risks associated with the righting time, the protection offered by the shells, and the resource value played an important role in the hiding time of the crabs using different shells. This study shows that hermit crabs are aware of the attributes of the shell and use this information to make decisions about how long to stay hidden after being threatened.


Sign in / Sign up

Export Citation Format

Share Document