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Drilling costs can be 80% of geothermal project investment, so decreasing these deep drilling costs substantially reduces overall project costs, contributing to less expensive geothermal electricity or heat generation. Plasma Pulse Geo Drilling (PPGD) is a contactless drilling technique that uses high-voltage pulses to fracture the rock without mechanical abrasion, which may reduce drilling costs by up to 90% of conventional mechanical rotary drilling costs. However, further development of PPGD requires a better understanding of the underlying fundamental physics, specifically the dielectric breakdown of rocks with pore fluids subjected to high-voltage pulses. This paper presents a numerical model to investigate the effects of the pore characteristics (i.e., pore fluid, shape, size, and pressure) on the occurrence of the local electric breakdown (i.e., plasma formation in the pore fluid) inside the granite pores and thus on PPGD efficiency. Investigated are: (i) two pore fluids, consisting of air (gas) or liquid water; (ii) three pore shapes, i.e., ellipses, circles, and squares; (iii) pore sizes ranging from 10 to 150 μm; (iv) pore pressures ranging from 0.1 to 2.5 MPa. The study shows how the investigated pore characteristics affect the local electric breakdown and, consequently, the PPGD process.

Plasma Pulse Geo Drilling (PPGD) is a contact-less drilling technique, where an electric discharge across a rock sample causes the rock to fracture. Experimental results have shown PPGD drilling operations are successful if certain electrode spacings, pulse voltages, and pulse rise times are given. However, the underlying physics of the electric breakdown within the rock, which cause damage in the process, are still poorly understood. This study presents a novel methodology to numerically study plasma generation for electric pulses between 200 and 500 kV in rock pores with a width between 10 and 100 μm. We further investigate whether the pressure increase, induced by the plasma generation, is sufficient to cause rock fracturing, which is indicative of the onset of drilling success. We find that rock fracturing occurs in simulations with a 100 μm pore size and an imposed pulse voltage of approximately 400 kV. Furthermore, pulses with voltages lower than 400 kV induce damage near the electrodes, which expands from pulse to pulse, and eventually, rock fracturing occurs. Additionally, we find that the likelihood for fracturing increases with increasing pore voltage drop, which increases with pore size, electric pulse voltage, and rock effective relative permittivity while being inversely proportional to the rock porosity and pulse rise time.

UDP-glucose:glycoprotein glucosyltransferase (UGGT) 1 and 2 are central hubs in the chaperone network of the endoplasmic reticulum (ER), acting as gatekeepers to the early secretory pathway, yet little is known about their cellular clients. These two quality control sensors control lectin chaperone binding and glycoprotein egress from the ER. A quantitative glycoproteomics strategy was deployed to identify cellular substrates of the UGGTs at endogenous levels in CRISPR-edited HEK293 cells. The 71 UGGT substrates identified were mainly large multidomain and heavily glycosylated proteins when compared to the general N-glycoproteome. UGGT1 was the dominant glucosyltransferase with a preference toward large plasma membrane proteins whereas UGGT2 favored the modification of smaller, soluble lysosomal proteins. This study sheds light on differential specificities and roles of UGGT1 and UGGT2 and provides insight into the cellular reliance on the carbohydrate-dependent chaperone system to facilitate proper folding and maturation of the cellular N-glycoproteome.

There is a potential for synergy effects in utilizing CO2 for both enhanced gas recovery (EGR) and geothermal energy extraction (CO2-plume geothermal, CPG) from natural gas reservoirs. In this study, we carried out reservoir simulations using TOUGH2 to evaluate the sensitivity of natural gas recovery, pressure buildup, and geothermal power generation performance of the combined CO2-EGR–CPG system to key reservoir and operational parameters. The reservoir parameters included horizontal permeability, permeability anisotropy, reservoir temperature, and pore-size-distribution index; while the operational parameters included wellbore diameter and ambient surface temperature. Using an example of a natural gas reservoir model, we also investigated the effects of different strategies of transitioning from the CO2-EGR stage to the CPG stage on the energy-recovery performance metrics and on the two-phase fluid-flow regime in the production well. The simulation results showed that overlapping the CO2-EGR and CPG stages, and having a relatively brief period of CO2 injection, but no production (which we called the CO2-plume establishment stage) achieved the best overall energy (natural gas and geothermal) recovery performance. Permeability anisotropy and reservoir temperature were the parameters that the natural gas recovery performance of the combined system was most sensitive to. The geothermal power generation performance was most sensitive to the reservoir temperature and the production wellbore diameter. The results of this study pave the way for future CPG-based geothermal power-generation optimization studies. For a CO2-EGR–CPG project, the results can be a guide in terms of the required accuracy of the reservoir parameters during exploration and data acquisition.

The site of protein folding and maturation for the majority of proteins that are secreted, localized to the plasma membrane or targeted to endomembrane compartments is the endoplasmic reticulum (ER). It is essential that proteins targeted to the ER are properly folded in order to carry out their function, as well as maintain protein homeostasis, as accumulation of misfolded proteins could lead to the formation of cytotoxic aggregates. Because protein folding is an error-prone process, the ER contains protein quality control networks that act to optimize proper folding and trafficking of client proteins. If a protein is unable to reach its native state, it is targeted for ER retention and subsequent degradation. The protein quality control networks of the ER that oversee this evaluation or interrogation process that decides the fate of maturing nascent chains is comprised of three general types of families: the classical chaperones, the carbohydrate-dependent system, and the thiol-dependent system. The cooperative action of these families promotes protein quality control and protein homeostasis in the ER. This review will describe the families of the ER protein quality control network and discuss the functions of individual members.

Advanced Geothermal Systems (AGS) may in principle be able to satisfy the global energy demand using standard continental-crust geothermal temperature gradients of 25–35 ∘C/km. However, conventional mechanical rotary drilling is still too expensive to cost-competitively provide the required borehole depths and lengths for AGS. This highlights the need for a new, cheaper drilling technology, such as Plasma-Pulse Geo-Drilling (PPGD), to improve the economic feasibility of AGS. PPGD is a rather new drilling method and is based on nanoseconds-long, high-voltage pulses to fracture the rock without mechanical abrasion. The absence of mechanical abrasion prolongs the bit lifetime, thereby increasing the penetration rate. Laboratory experiments under ambient-air conditions and comparative analyses (which assume drilling at a depth between 3.5 and 4.5 km) have shown that PPGD may reduce drilling costs by approximately 17–23%, compared to the costs of mechanical drilling, while further research and development are expected to reduce PPGD costs further. However, the performance of the PPGD process under deep wellbore conditions, i.e., at elevated temperatures as well as elevated lithostatic and hydrostatic pressures, has yet to be systematically tested. In this paper, we introduce a standard experiment parameter to examine the impact of deep wellbore conditions on PPGD performance, namely the productivity (the excavated rock volume per pulse) and the specific energy (the amount of energy required to drill a unit volume of rock). We employ these parameters to investigate the effect of temperature on PPGD performance, with temperatures increasing up to 80 ∘C, corresponding to a drilling depth of up to approximately 3 km.HighlightsThis study introduces an experiment protocol for studying the impact of deep wellbore conditions on Plasma-Pulse Geo-Drilling performance.When deionized water is used, increasing the temperature decreases Plasma-Pulse Geo-Drilling productivity and increases the specific energy.The effect of increasing temperature on Plasma-Pulse Geo-Drilling depends significantly on the drilling fluid used.Deionized water negatively affects Plasma-Pulse Geo-Drilling, while other studies have shown that the effect of oil-based drilling muds is negligible.

Monitoring a process that has contaminated data with traditional control charts such as Shewhart's X̄ chart and the Range chart results in an excessive number of false alarms. Robust control charts such as the Median and IQR charts are a better alternative to traditional charts for a process with contaminated data because the effects of the outlying data values are eliminated. However, process shifts are not detected as quickly with the robust charts. This paper introduces a diagnostic statistic technique that uses traditional control chart methods augmented by diagnostic tools. Performance measures for traditional, robust, and diagnostic statistic control chart systems for n = 5 are reported. Contour plots for n = 3 and n = 5 are provided to allow for interpolation of parameter values. The diagnostic statistic technique improves work stoppage (comparable to average run length) rates for contaminated data and maintains the ability to identify process shifts.

Forecast-based monitoring schemes have been researched extensively in regards to applying traditional control charts to forecast errors arising from various autocorrelated processes. The dynamic response and behavior of forecast errors after experiencing a shift in the process mean make it difficult to choose a suitable control chart. In this paper we propose the reverse moving average control chart as a new forecast-based monitoring scheme, compare the new control chart to traditional methods applied to various ARMA(1,1), AR(1), and MA(1) processes, and make recommendations concerning the most appropriate control chart to use in a variety of situations when charting autocorrelated processes.

ABSTRACT UDP-glucose: glycoprotein glucosyltransferase (UGGT) 1 and 2 are central hubs in the chaperone network of the endoplasmic reticulum (ER), acting as gatekeepers to the early secretory pathway yet little is known about their cellular clients. These two quality control sensors control lectin chaperone binding and glycoprotein egress from ER. A quantitative glycoproteomics strategy was deployed to identify cellular substrates of the UGGTs at endogenous levels in CRISPR-edited HEK293 cells. The seventy-one UGGT substrates identified were mainly large multidomain and heavily glycosylated proteins when compared to the general N-glycome. UGGT1 was the dominant glucosyltransferase with a preference towards large plasma membrane proteins whereas UGGT2 favored the modification of smaller, soluble lysosomal proteins. This study sheds light on differential specificities and roles of UGGT1 and UGGT2 and provides insight into the cellular reliance on carbohydrate-dependent chaperone intervention by UGGT1 and UGGT2 to facilitate proper folding and maturation of the cellular N-glycome. Competing Interest Statement The authors have declared no competing interest.

CO2 Plume Geothermal (CPG) energy is a method for producing electricity from heat extracted from hot rock layers or reservoirs deep within the earth's crust. CPG is differentiated from other geothermal technologies by several factors: 1) CPG uses CO2 as the primary geologic working fluid instead of brine, 2) CPG utilizes naturally permeable porous reservoirs to extract heat, such as saline aquifers or depleted hydrocarbon reservoirs, 3) CPG is deep—a CPG reservoir must have a depth of 1 km to maintain CO2 in its supercritical state; though depths of 2 to 5 km are more common, and 4) CPG utilizes reservoirs at common geologic temperature gradients, unlike traditional hydrothermal which utilizes shallow reservoirs of unusually high temperature. Thus, CPG is intended to be integrated into an existing CO2 sequestration site affording an economic return on CO2 capture expenses by providing carbon-neutral, dispatchable electricity. Even when CPG is used as a base-load power source, it correlates well with electrical demand, unlike wind and solar (Chapter 5). Typically, CPG configurations consist of one or more injection and production wells. These wells link the surface plant with the porous reservoir to create a fluid circuit. Cooled fluid is injected at the surface, heated within the reservoir, and then returned to the surface at higher temperature and pressure which can then be used to create electricity. The variation in CO2 density between injection and production wells creates a thermosiphon which can drive circulation of CO2 without the use of pumps (Chapter 2). The geologic CO2 can be passed directly through a turbine, called a direct system, or heat can be extracted and used to power an Organic Rankine Cycle, called an indirect system. Either system may be used to generate electricity, although a direct system will nearly always produce more electricity than the indirect system. With reservoirs at moderate depth and temperature, these direct systems will also produce more electricity than comparable brine hydrothermal systems (Chapter 3). The reservoir well spacing and diameter affect the average power and longevity of a CPG system. For every combination of well diameter and reservoir depth, temperature, permeability, and thickness, an optimum spacing between the central injection well and a circumferential collection well will provide the greatest power output over time; placing the collection well too close to the injection well depletes the reservoir too quickly while spacing it too far away increases pressure losses, decreasing the overall power (Chapter 4). Likewise, the selection of too small a well diameter will limit mass flowrate, and thus power, while an oversized well diameter may quickly deplete the reservoir and provide no additional benefit (Chapters 3 & 4). This research has provided a significantly deeper understanding of CPG power systems and their operation. The impact of this work is to establish a basis of CPG research to be used in several ways. It can directly inform industrial developments, such as a green-field implementation of CPG or the long-term planning of a CPG-ready Carbon Capture and Storage site. This work may also be the basis for future economic or policy analyses that can further argue for the development of CPG. Thus, this work will help enable CPG as part of the 21st century energy portfolio.