An Early Version of the Bulgarian Copper Dinars of the 13th Century

The author considers copper coins of the so-called “archaic” type minted in Bulgar. According to the author, they were issued in the mid – late 1230s. The main feature of these coins is a kind of legend handwriting and great weight. The work is the Corpus – the publication of all copies of the “archaic” dinars known to date. In addition to weight and diameter, the article provides photo images of most of the coins presented in the table. Materials are presented from the funds of the National Museum of the Republic of Tatarstan, State Historical Museum (Moscow), ZENO database. Coins from the Bolgar State Historical and Architectural Museum-Reserve are first presented. After analyzing the weight histogram compiled from materials of weight 84 dinars, the author calculates the average weight – 6.01 g. Later, in the 1240s, copper coins with a weight of 3.1–3.3 g began to be issued in the Bulgar region. The article also provides rare versions of heavy-weight dinars minted, according to the author, immediately after the “archaic” type.

Upscaling Float-over Installation

This paper presents the latest developments in Transport and Installation methods for Topsides up to 38,500mt. For such heavy-weight structures Boskalis introduces a solution by combining the beneficial features of a Heavy Transport Vessel dry-transportation with the advantages of a DP2 Barge float-over installation. This unique Transport and Installation approach, a so called "Piggyback T&I", may be characterized as follows:

Caged

There I stood, in the middle of a moment that uttered assumptions of me, of my people. It was so subtle but hardly dismissible. It turned my insides and left a heavy weight in my chest. I felt like I couldn’t speak, like a puppet controlled by my environment, ruled by what others had been brainwashed to believe, what I had believed, dominated and bound to this cage.

Research on a New Type of Lattice Roller Frame

In view of the structural defects of the current belt conveyor roller frame, such as heavy weight and high labor intensity of disassembly and assembly, a new lattice roller frame was designed by changing the structure and profile. On the premise of meeting the work conditions, the weight of the roller frame was reduced by more than 45%, which not only reduced the labor intensity of disassembly and assembly, but also reduced the tonnage and cost of consumables of the belt conveyor, and it has a broad market prospect.

Heavy Weight Cement System for Corrosive Environment: Preventing Strength Retrogression and H2S Corrosion

Well cementing in high temperature and hydrogen sulfide (H2S) corrosive environment presents challenges in preventing cement compressive strength retrogression and selecting weighting agents inert to H2S. This paper presents the development of a cementing system for high pressure high temperature (HPHT) well with bottom hole static temperature in excess of 165°C, a drilling fluid density of 2.19 SG and a high concentration of H2S. A major operator in the Caspian Sea region accepted the cement design and successfully used it on the production liner section of the HPHT well. Cementing of the production liner was complex due to the requirement for a high-density cement system, narrow margin between the pore pressure and frac gradient, HPHT conditions and 18% H2S concentration in the formation fluid. Comprehensive laboratory testing was performed to evaluate the properties of the cement system including measurements of thickening time and compressive strength evaluation using a UCA and destructive method using ultra-HPHT curing chamber for cube sample curing. The presence of H2S limited the use of conventional weighting agents such as hematite and hausmannite, and the high temperature environment dictated the need for quartz silica. These factors required a nonstandard approach to cement blend formulation and flowability assessment. During cement system optimization, the target slurry density was achieved using barite which has a lower density compared to other common weighting agents and significantly reduces cement content in the blend but also is inert to H2S corrosion. A further challenge encountered during cement system optimization was strength retrogression that could not be prevented by the conventional approach of adding 30-40% quartz silica by weight of cement into the system. To overcome strength retrogression, much higher concentrations of silica were required. As a result, the low cement content led to insufficient compressive strength development at liner hanger depth. A solution was found by adding a Vinylamide/Vinylsulfonated polymer (VA/VS) polymer in a certain proportion to the slurry design. Thus, at elevated temperatures, it was observed that the VA/VS polymer tended not to delay compressive strength development while still extending the slurry thickening time. The developed heavy weight cement system was successfully implemented to isolate the 7-in liner on HPHT well. All the stages of job planning, design and execution, along with the slurry optimization process are presented.

Assessing Biodegradable Mulch Duration and Nutsedge Suppression during Late Summer Cucumber Production in Mississippi and Louisiana

Environmental concerns as well as labor costs associated with the use of polyethylene plastic mulch have turned producers’ focus to alternative mulch treatments. A preliminary study was conducted to evaluate nutsedge control, mulch degradation, and cucumber yields on biodegradable mulches at two locations (Louisiana and Mississippi). Mulch treatments included two paper-based mulch products, two biodegradable plastic mulches, the industry standard non-biodegradable black plastic mulch, and an unmulched control. The heavy weight paper-based mulch and light weight paper mulches in the Louisiana location were reduced to 50% or less coverage at the end of the study. Similarly, the paper-based mulches both degraded below 40% at the conclusion of the study at the Mississippi location. The heavy weight paper mulch was able to hold back nutsedge (p ≤ 0.05) at similar rates as the two biodegradable plastic mulches and industry standard plastic mulch, while the light weight paper mulch and unmulched plots were ineffective at reducing emerged sedges. There were no statistical differences in nutsedge control (averaging < 14 emerged plants per 1.5 m subplots) between all mulch materials at the conclusion of the study in the Mississippi location. Combining both states yield data, the heavyweight mulch (8.7 fruit, 5.3 lb) performed comparably to the industry standard plastic mulch (5.8 fruit, 3.5 lb) in terms of both average fruit number and average weights harvested off 9.1 m rows at each harvest date.