Interactions among seedling diameter grade, weed control, and soil cultivation for Pinusradiata in South Africa

1993 ◽  
Vol 23 (10) ◽  
pp. 2078-2082 ◽  
Author(s):  
David B. South ◽  
J. B. Zwolinski ◽  
D. G. M Donald
Keyword(s):  
South Africa ◽  
Weed Control ◽  
Standard Method ◽  
Seedling Survival ◽  
Large Diameter ◽  
Small Diameter ◽  
Diameter Growth ◽  
Low Grade ◽  
Soil Cultivation ◽  
Better Than

A study was established in the southern Cape Province, South Africa, to examine survival and growth in response to seedling grade and various methods of site preparation. Second-year performance was examined in relation to (i) initial groundline diameter, (ii) intensity of weed control, and (iii) method of soil cultivation. Weeds were controlled with (i) manual release 1 year after planting (the standard method used by the Department of Water Affairs and Forestry) or (ii) total weed control for 1 year involving the use of herbicides and additional hoeing. Soil cultivation treatments included (i) pitting by hand, (ii) pitting with a mechanical auger, (iii) ripping, and (iv) ripping plus disking. The influence of initial seedling diameter on survival was significant. Seedlings with a 2-mm groundline diameter averaged 62% survival, whereas 5-mm seedlings averaged 85% survival. Use of large-diameter stock improved survival regardless of soil cultivation or weed control treatments. For survival, there was an interaction between soil cultivation treatments and the use of herbicides. Total weed control with herbicides and hoeing improved survival for plots that received ripping or disking treatments. However, seedling survival was decreased where herbicides were used on plots where pits were used. On average, seedlings with larger diameters grew better than those with smaller diameters. However, small-diameter seedlings with total weed control grew better than large-diameter seedlings with standard weed control. Average seedling volume after 2 years was 33% greater for high-grade seedlings (2.4 dm3) than for low-grade seedlings (1.8 dm3). However, there were interactions between soil cultivation and weed control treatments for height and diameter growth. With the standard method of weed control, ripping improved height and diameter growth. Total weed control with herbicides and hoeing greatly improved growth for all treatments, and as a result, little or no differences in average seedling volume were observed between pitting and ripping treatments.

Integration of nursery practices and vegetation management: economic and biological potential for improving regeneration

1993 ◽  
Vol 23 (10) ◽  
pp. 2083-2092 ◽  
Author(s):  
David B. South ◽  
Robert J. Mitchell ◽  
Bruce R. Zutter ◽  
John M. Balneaves ◽  
Brad L. Barber ◽  
...  
Keyword(s):  
Weed Control ◽  
Management Practices ◽  
Large Diameter ◽  
Small Diameter ◽  
Site Preparation ◽  
Growth Responses ◽  
Biological Potential ◽  
Nursery Practices ◽  
Stock Types ◽  
Returns On Investment

Researchers in New Zealand, Scotland, South Africa, Texas, and Alabama provided data on growth responses owing to nursery management practices and weed control after outplanting. Nursery treatments included nitrogen fertilization (0 vs. 168 kg/ha), seedling grades (small-diameter vs. large-diameter seedlings), and a comparison of stock types. Weed-control treatments varied by study and included broadcast and spot applications. Interactions between nursery practices and weed control were examined. Regardless of location, growth (2–8 years after planting) was increased as seedling diameter increased. Practices that increase average seedling diameter in the nursery are typically less costly than silvicultural practices required to obtain similar growth responses from small-diameter stock. Although interactions were observed among sites, stock size, and intensity of weed control, large-diameter stock consistently grew better than small-diameter stock regardless of site or site-preparation method. Thus, increasing the investment of regeneration expenditures at the nursery, relative to that put into site preparation, will substantially improve financial returns on investment. Further research needs in this area are also discussed.

Assessment of the Remaining Strength of Corroded Small Diameter (Below 6”) Pipelines and Pipework

2012 ◽  
Author(s):  
Troy Swankie ◽  
Vinod Chauhan ◽  
Robert Owen ◽  
Robert Bood ◽  
Geoffrey Gilbert
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Ductile Failure ◽  
Corrosion Damage ◽  
Full Scale ◽  
Alternative Methods ◽  
Low Grade ◽  
Numerical Work ◽  
Line Pipe ◽  
Failure Pressure

Internal and external corrosion damage is a major cause of pipeline failures worldwide. When corrosion features in pipelines are detected by in-line inspection (ILI), a decision whether to replace, repair or accept and monitor must be made. Extensive experimental and numerical work has been undertaken to develop methods for assessing the remaining strength of corroded transmission pipelines. Common methods used by the pipeline industry include ASME B31G, modified ASME B31G and LPC. These methods are semi-empirical and have been developed using a modified version of a toughness independent ductile failure criterion for pressurized pipes containing axially orientated surface breaking defects. The validity range of these models is dominated by large diameter (10 to 48″), thin walled, low grade (API 5L grade A to X65) and low yield to tensile ratio line pipe. Smaller diameter (not greater than 6″), thick walled pipelines and pipework located, for example, at above ground installations, compressor and pressure reduction stations are very common. The use of ASME B31G, modified ASME B31G or LPC may not be appropriate when assessing the remaining strength of small diameter pipelines and pipework. No alternative methods are available in the public domain and hence a program of work was undertaken to derive appropriate defect acceptance limits by conducting a series of full-scale burst tests on small diameter pipe with simulated corrosion defects. It was concluded that the LPC method gave the most accurate prediction of failure pressure when compared with the results of the full-scale tests, and the most conservative predictions of failure pressure were obtained using the ASME B31G method.

Experimental Research on Ice Accretion Characteristic of Energy-Saving Conductor

2014 ◽  
Vol 986-987 ◽  
pp. 919-922
Author(s):  
Han Jie Huang ◽  
Hua Jin ◽  
Zhi Xiang Huang ◽  
Xin Min Li
Keyword(s):  
Energy Saving ◽  
Large Diameter ◽  
Small Diameter ◽  
Wind Tunnel Test ◽  
Ice Accretion ◽  
Transmission Losses ◽  
New Type ◽  
Power Project ◽  
Test Result ◽  
Better Than

New type of energy-saving conductor which can obviously reduce the transmission losses was recently developed in power project. However, considering ice-coating and galloping in winter, it is necessary to investigate its ice accretion characteristic compared with conventional conductor. Research was conducted by icing wind tunnel test. Ice mass and ice shape of conductor with different diameter were examined. There is no clear advantage on the ice-coating resistance capability of energy-saving conductor with small diameter, while for conductor with larger diameter, energy-saving conductor’s ice-coating resistance capability is better than conventional conductor. The test result is helpful for choosing suitable type of large diameter conductor in high and ultra-high voltage transmission project.

Study on Lateral Pressure of Bulk Materials in Silos

2011 ◽  
Vol 201-203 ◽  
pp. 2653-2656
Author(s):  
Chang Bing Chen
Keyword(s):  
Static Pressure ◽  
Lateral Pressure ◽  
Large Diameter ◽  
Small Diameter ◽  
Present Calculation ◽  
Calculation Methods ◽  
Bulk Materials ◽  
New Formula ◽  
Current Code ◽  
Better Than

With the development of modern industry, silo diameters are bigger and bigger. Lateral pressure of bulk materials in silos is one important parameter for designing silos, which is related to the economy and safety of the structure. However, present calculation methods of the lateral pressure are mostly based on small diameter silos. For now, in the Chinese code the wall pressure computation methods are based on Rankine theory to be calculated. It is shown that the calculated results of Rankine theory may overestimate the pressure. In this paper, the lateral pressure of large diameter silos is studied. A new formula for calculating lateral static pressure on shallow silo wall is derived by static equilibrium method. The formula of this paper is simple of calculation and can be used for large diameter silos with a circular con top pile. The results agree with that of the full-sized silo experiment better than the current code.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

Improvement of environmental health and hygiene practices - case study in the Northern Province

2001 ◽  
Vol 44 (6) ◽  
pp. 109-117 ◽  
Author(s):  
M. A. Mathegana ◽  
L. K. Chauke ◽  
F. A.O. Otieno
Keyword(s):  
South Africa ◽  
Environmental Health ◽  
Northern Province ◽  
Active Involvement ◽  
Sustainable Improvement ◽  
Hygiene Practices ◽  
Proper Training ◽  
The Government ◽  
Better Than

The primary purpose of an improved water supply and sanitation is the achievement of acceptable health and hygiene standards as well as the sustainable improvement of the environment. Many governments recognize this and so they budget for large sums of money to improve these services to the communities. The purpose of this study was to investigate the different gaps in environmental health and hygiene practices with the aim of suggesting a strategy of improving this in the Northern Province of South Africa. To do this, 231 households and 30 schools were surveyed. Workshops and visits to different government departments were also used. This paper reports the results from this study which indicate that the situation in schools was not any better than that in households, with more than 90% of the villages still dependent on the unimproved pit latrines and 56,6% relying on standpipes which were (70% of the time) non-operational. The main problems identified seem to those associated with implementation and maintenance. The study concludes that with proper training of the water committees and their active involvement with the government and NGOs, environmental health and hygiene problems can be minimized or eliminated.

Analysis Influence of Pile Embedded Depth and Diameter on Pile Tip Resistance

2013 ◽  
Vol 353-356 ◽  
pp. 459-462
Author(s):  
Ying Jie Zheng ◽  
Bin Fang ◽  
Lian Xiang Li
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Stiffness Ratio ◽  
Initial Stiffness ◽  
Tip Resistance

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.

scholarly journals Low-Grade Gliomas: Six-month Tumor Growth Predicts Patient Outcome Better than Admission Tumor Volume, Relative Cerebral Blood Volume, and Apparent Diffusion Coefficient

Radiology ◽  
2009 ◽  
Vol 253 (2) ◽  
pp. 505-512 ◽  
Author(s):  
Gisele Brasil Caseiras ◽  
Olga Ciccarelli ◽  
Daniel R. Altmann ◽  
Christopher E. Benton ◽  
Daniel J. Tozer ◽  
...  
Keyword(s):  
Patient Outcome ◽  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Tumor Growth ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Tumor Volume ◽  
Low Grade ◽  
Apparent Diffusion ◽  
Better Than
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