Geographies of production in 3D: Theoretical and research implications stemming from additive manufacturing

Additive manufacturing (or 3D printing) is a comparatively new and evolving form of production that has the potential to transform the geographies of manufacturing. While this technology has garnered significant hype in the popular media, the topic has been virtually ignored in academic circles outside of business- and industry-specific, technology-oriented journals. Given its prospective impacts on the secondary sector and the potential for geographers to explore these transitions, this article provides a discussion of the possible opportunities for theoretical explorations and research into the place-based facets of additive manufacturing and its impacts on, or integration with, traditional manufacturing. In particular, we examine the spatial ramifications of this technology on supply, demand, innovation, global production networks, and the role of the state juxtaposed against contemporary insights pertaining to advances in additive manufacturing.     

探采结合水井无固相环保冲洗液的研究与应用

探采结合水井需要实现精确获取水文地质参数和解决百姓饮水难题的双重目的,因此要求钻进施工中采用的冲洗液既要具备基本的护壁防塌等功能,还需最大程度地降低对地层渗透性的影响,同时还应具有优良的环保性能。针对这一特殊要求,研发了新型的PA—1型无固相环保冲洗液,采用渗透性实验、电镜扫描、砂球浸泡实验等多种测试手段对冲洗液进行了室内评价与分析,结果表明PA—1型无固相环保冲洗液对地层渗透性影响较小,防塌护壁能力强,综合性能优于常规冲洗液体系;采用中华米虾对其进行急性毒性实验也表明其安全无毒。大量室内实验及现场应用表明,PA—1型无固相环保冲洗液各项性能优良,可为今后在探采结合水井施工中冲洗液的合理选用提供参考。     

西方“地方生产网络”相关研究综述

生产网络是西方经济地理学的研究热点之一。其对全球经济的透彻解析所形成的全球生产网络概念已受到普遍关注,而作为地方经济分析工具的地方生产网络概念却明显受到忽视。本文参阅西方地方生产网络相关研究成果,对地方生产网络概念进行了梳理和界定,从构成与形态、内部关系、影响因素、外部连接、学习与创新、升级和演化等方面进行了评述,认为地方生产网络将会在分析地方经济内部结构、外部关系和创新能力等方面发挥更加重要的作用。     

加拿大马更些冻土区天然气水合物试生产进展与展望

马更些（Mackenzie）冻土区位于加拿大西北地区,是世界上最著名的天然气水合物产地之一,也是加拿大最重要的含油气盆地之一。在Mallik地区已相继钻探了L 38、2L 38、3L 38、4L 38和5L 38共5个钻孔,并进行了地质、地球物理、地球化学、微生物学和试生产等方面的多学科多方法研究,是目前全球天然气水合物研究程度最高、资料最丰富的地区。“Mallik 2002”项目开展了天然气水合物的短期试生产,共对6个水合物层位进行了降压法试生产并在其中的4个层位取得了成功,同时利用注入约80℃的热流体进行了5天多的加热法试生产,共生产出468 m3的天然气。“Mallik 2002”项目的成功实施是天然气水合物开发利用史上的里程碑,为将来的长期试生产和最终开发利用奠定了基础。随着开发利用研究的不断深入,天然气水合物这一规模巨大的潜在能源有可能在不久的将来为人类社会所用。     

Distribution and cycling of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in the sea-surface microlayer of the Yellow Sea, China, in spring

The distributions of dimethylsulfide (DMS) and its precursor, dimethylsulfoniopropionate (DMSP), were examined in the surface microlayer and corresponding subsurface water of the Yellow Sea, China, in April 2006. The average concentrations of DMS and DMSP of dissolved (DMSPd) and particulate (DMSPp) forms were 5.42 (1.78–12.75), 9.22 (2.85–19.73) and 17.50 (4.33–36.09) nmol L⁻¹ in the subsurface water, and those in the surface microlayer were 4.92 (1.69–10.66), 17.08 (3.13–38.82) and 22.54 (4.85–47.24) nmol L⁻¹, respectively. The enrichment factor (EF) of DMS in the microlayer ranged from 0.47 to 2.24 with a mean of 0.98. In contrast, DMSPd and DMSPp appeared to be enriched in the microlayer with average EFs of 1.98 and 1.39, respectively. A close correlation of integrated DMS, DMSPp and chlorophyll a concentrations for compiled data from all stations in the microlayer and the subsurface water indicated that phytoplankton biomass might play an important role in controlling the distributions of biogenic sulfurs in the study area. Moreover, a statistically significant relationship was found between the microlayer concentrations of DMS, DMSP and chlorophyll a and their subsurface water concentrations, suggesting a close linkage between these two water compartments. Interestingly, we observed higher biological production rates and consumption rates of DMS in the microlayer relative to the subsurface water. Furthermore, the DMS production rates were closely correlated both with DMSPd and chlorophyll a concentrations. Our study showed that the major sink of DMS in microlayer was escape into the atmosphere, which greatly exceeded its bacterial consumption. A preliminary estimate for average flux of DMS from the Yellow Sea to the atmosphere was 6.41 μmol m⁻² d⁻¹ during spring.     

Economic valuation for the conservation of marine biodiversity

Policy makers are increasingly recognising the role of environmental valuation to guide and support the management and conservation of biodiversity. This paper presents a goods and services approach to determine the economic value of marine biodiversity in the UK, with the aim of clarifying the role of valuation in the management of marine biodiversity. The goods and services resulting from UK marine biodiversity are detailed, and 8 of the 13 services are valued in monetary terms. It is found that a decline in UK marine biodiversity could result in a varying, and at present unpredictable, change in the provision of goods and services, including reduced resilience and resistance to change, declining marine environmental health, reduced fisheries potential, and loss of recreational opportunities. The results suggest that this approach can facilitate biodiversity management by enabling the optimal allocation of limited management resources and through raising awareness of the importance of marine biodiversity.     

海湾扇贝南部亚种(Argopecten irradians concentricus)选育系F5的生长及SSR分析

采用现场测量和11对微卫星标记引物对海湾扇贝南部亚种选育系F5与普通养殖群体的生产性能、遗传差异及遗传多样性现状进行分析。结果表明:在生产性能上,选育系的壳高、壳长、壳宽、体重、壳重、软体重、肉柱重、肉柱率、成活率和笼产量等性状较对照组分别提高了17.02%、16.67%、15.02%、43.71%、35.86%、58.74%、81.18%、29.46%、17.94%和69.47%。在遗传差异的SSR分析上,选育系和普通群体的平均等位基因数(Na)、平均有效等位基因数(Ne)、平均观测杂合度(Ho)、平均期望杂合度(He)、多态信息含量(PIC)分别为3.2727、3.3636;2.3366、2.3203;0.3152、0.3545;0.5326、0.5441;0.4622、0.4693;群体间遗传距离(Dxy)为0.1161,遗传分化指数(Fst)为0.0465。结果表明,选育系生产性能明显优于普通群体,遗传多样性指数较普通群体有所降低,两群体间出现了显著的遗传分化,选育系F5获得了显著的遗传进展。同时,选育系群体仍具有较高的遗传多样性,为进一步的选育利用提供了空间。     

太湖：过去、现在和将来

The presence of roads, farm house foundations, wells and Liangzhu period cultural relics in the bottom of Lake Taihu attest to the fact that this shallow depression was probably dry between 4 and 5 thousand years ago. This interpretation is corroborated by the sudden disappearance of algal pigments at sediment depths carbon-14 dated at 4-5 thousand years before present.In winter, the stronger winds are predominantly from the northeast. These winds result in a powerful counterclockwise current that transports lake sediments and has altered the very shape of the lake over the last 300 years. Winds produce a complex mixing pattern in Lake Taihu with storm induced sediment deposition occurring near the lake''s center.During approximately 240 days of the year, the wind blows across Lake Taihu with sufficient force to mix it to its bottom. As a result, this polymictic lake rarely becomes anoxic and dissolved oxygen at the mud water interface is maintained at or above 4 mg·l^-1. The consequences of this high dissolved oxygen are quite impressive as high organic loading to the lake would otherwise render its bottom waters anaerobic killing many of its natural inhabitants.Because suspended solids reduce (attenuate) light penetration, the major primary production takes place in the top metre of the lake (mean Secchi Transparency-0.25 m). Suspended clays are slow to settle and wind mixing keeps fine-grained suspended solids in suspension in all but the most quiet backwaters of the lake.In the recent past about 23 000 metric tonnes of phytoplankton were produced in Lake Taihu. This large production represents only about 5% of the total influx of organic material entering the lake. In summer and fall, cyanobacteria such as Microcystis spp. and Anabaena spp. dominate most of the lake. Recently, however, mixotrophic flagellates displaced cyanobacteria as the dominant algae in parts of Lake Taihu with high bacteria and high suspended solids (e.g. Wuli and Meiliang Bay). In the future, facultative heterotrophs may come to dominate an ever larger portion of the lake waterc column.     

Production rate calculations for cosmic-ray-muon-produced 10Be and 26Al benchmarked against geological calibration data

First, I benchmark existing methods of calculating subsurface ²⁶Al, ¹⁰Be, and ¹⁴C production rates due to cosmic-ray muons against published calibration data from bedrock cores and mine excavations. This shows that methods based on downward propagation of the surface muon energy spectrum fit calibration data adequately. Of these methods, one that uses a simpler geographic scaling method based on energy-dependent attenuation of muons in the atmosphere appears to fit calibration data better than a more complicated one that uses the results of a global particle transport model to estimate geographic variation in the surface muon energy spectrum. Second, I show that although highly simplified and computationally much cheaper exponential function approximations for subsurface production rates are not globally adequate for accurate production rate estimates at arbitrary location and depth, they can be used with acceptable accuracy for many exposure-dating and erosion-rate-estimation applications.     

Toward the feldspar alternative for cosmogenic 10Be applications

The possibility of quantifying surface processes in mafic or volcanic environment using the potentialities offered by the in situ-produced cosmogenic nuclides, and more specifically by the in situ-produced ¹⁰Be, is often hampered by the rarity of quartz minerals in the available lithologies. As an alternative to overcome this difficulty, we explore in this work the possibility of relying on feldspar minerals rather that on quartz to perform in situ-produced ¹⁰Be measurements in such environments. Our strategy was to cross-calibrate the total production rate of ¹⁰Be in feldspar (P_10fsp) against the total production rate of ³He in pyroxene (P_3px) by measuring ³He and ¹⁰Be in cogenetic pyroxene (³He_px) and feldspar (¹⁰Be_fsp). The samples were collected from eight ignimbritic boulders, exposed from ca 120 to 600 ka at elevations ranging from 800 to 2500 m, along the preserved rock-avalanche deposits of the giant Caquilluco landslide (18°S, 70°W), Southern Peru. Along with data recently published by Blard et al. (2013a) at a close latitude (22°S) but higher elevation (ca. 4000 m), the samples yield a remarkably tight cluster of ³He_px - ¹⁰Be_fsp total production ratios whose weighted-mean is 35.6 ± 0.5 (1σ). The obtained weighted-mean ³He_px - ¹⁰Be_fsp total production ratio combined with the local ³He_py total production rate in the high tropical Andes published by Martin et al. (2017) allows to establish a total SLHL ¹⁰Be in situ-production rate in feldspar mineral (P_10fsp) of 3.57 ± 0.21 at.g⁻¹.yr⁻¹ (scaled for the LSD scaling scheme, the ERA40 atm model and the VDM of Lifton, 2016).Despite the large elevation range covered by the whole dataset (800–4300 m), no significant variation of the ³He_px - ¹⁰Be_fsp total production ratios in pyroxene and feldspar was evidenced. As an attempt to investigate the effect of the chemical composition of feldspar on the total ¹⁰Be production rate, major and trace element concentrations of the studied feldspar samples were analyzed. Unfortunately, giving the low compositional variability of our dataset, this issue is still pending.